JP7549157B2 - Power control device, power control method, and power control program - Google Patents

Description

The present invention relates to power control technology in construction machinery.

Known construction machines (hereinafter also referred to as construction machines) used at construction sites include electric construction machines driven by electric motors (hereinafter also referred to as electric motors or motors) and hybrid construction machines that use hydraulic equipment and electric motors together (hereinafter collectively referred to as electric construction machines). An actuator that directly drives each joint component of an electric construction machine with a mechanical element such as a ball screw driven by the rotational power of a motor is called an electro-mechanical actuator (EMA), and an actuator that indirectly drives each joint component of an electric construction machine with hydraulic equipment such as a hydraulic pump driven by the rotational power of a motor is called an electro-hydraulic actuator (EHA).

JP 2008-88660 A

The electric construction machine of Patent Document 1 is provided with a generator that generates electricity to drive each joint component, such as the lower traveling body, upper rotating body, boom, arm, bucket, etc. The amount of electricity generated by the generator fluctuates, and the electricity required by each joint component also fluctuates significantly depending on the operation of the electric construction machine. For this reason, there is a possibility that the electricity required by each joint component may not be appropriately supplied from the generator.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a power control device that can appropriately allocate power in construction machinery.

In order to solve the above problems, one aspect of the power control device of the present invention is a power control device for a construction machine that includes a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components, and includes a drive information acquisition unit that acquires drive information for the plurality of drive units, an identification unit that identifies an operation performed by the construction machine by the plurality of joint components based on the drive information, and a determination unit that determines the power to be supplied to the plurality of drive units in accordance with the identified operation of the construction machine. According to this aspect, the amount of power supplied to each drive unit is determined in accordance with the operation of the construction machine recognized based on the drive information of each drive unit, thereby achieving appropriate power distribution between each drive unit.

Another aspect of the present invention is a power control method. This method is a power control method for a construction machine that includes a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components, and includes a drive information acquisition step of acquiring drive information for the plurality of drive units, an identification step of identifying operations performed by the construction machine by the plurality of joint components based on the drive information, and a determination step of determining power to be supplied to the plurality of drive units in accordance with the identified operation of the construction machine.

In addition, any combination of the above components, and any conversion of the expression of the present invention between a method, device, system, recording medium, computer program, etc., are also valid aspects of the present invention.

According to the present invention, power can be appropriately allocated in construction machinery.

FIG. 1 is a schematic configuration diagram of an electric construction machine. FIG. 1 shows a first configuration example of a drive device for an electric construction machine. 2 shows an example of the configuration of a charge/discharge circuit. 2 shows a second configuration example of a drive device for an electric construction machine. 13 shows a third configuration example of a drive device for an electric construction machine. 1 shows a schematic diagram of the change over time t of the voltage V supplied by the charge/discharge converter to the DC/AC voltage bus. 1 shows an example of the configuration of a power control device for electric construction machinery. The motor current command value in each actuator is shown in the dq coordinate system. 4 is a flowchart illustrating an example of a power control process performed by a power control device. 10A to 10C are schematic diagrams illustrating examples of a determination process, a power allocation amount determination process, and a power supply process. 10 is a flowchart illustrating an example of a power supply amount determination process performed by a determination unit. 4 shows an example of power allocation to each actuator according to the operation of the working unit.

The technical idea of the drive device described in this embodiment can be applied to any electric machine equipped with a joint component. In this embodiment, an example of a construction machine or electric construction machine equipped with a lower traveling body, an upper rotating body, a boom, an arm, and a bucket as joint components is described, but this does not prevent the technical idea of the drive device of this embodiment from being applied to other electric machines. For example, the technical idea of the drive device of this embodiment may be applied to an industrial robot equipped with a joint or joint as a joint component. In addition, the technical idea of the drive device and/or power control device described in this embodiment can be applied to any construction machine equipped with a lower traveling body, an upper rotating body, a boom, an arm, and a bucket as joint components. In addition, in this embodiment, an EMA that directly drives each joint component of an electric construction machine by a mechanical element driven by the rotational power of a motor is exemplified as an actuator, but the technical idea of this embodiment can also be applied to an EHA that indirectly drives each joint component of an electric construction machine by a hydraulic device driven by the rotational power of a motor.

Figure 1 is a schematic diagram of the electric construction machine 100. Figure 2 is a top view of the electric construction machine 100. In the following description, the directions of front, back, up, down, left and right, etc. are the same as the directions of the electric construction machine 100. That is, in the following description, the front of the electric construction machine 100 in the traveling direction is simply referred to as the front, the rear of the electric construction machine 100 in the traveling direction is simply referred to as the rear, the upper side in the direction of gravity is simply referred to as the upper side, the lower side in the direction of gravity is simply referred to as the lower side, the right side in the vehicle width direction facing forward is simply referred to as the right side, and the left side in the vehicle width direction is simply referred to as the left side.

In the electric construction machine 100, which is a construction machine, an upper rotating body 102 is rotatably attached to a lower traveling body 101 that can travel forward and backward on the ground. A cab 103 is provided on the front left side of the upper rotating body 102, and a boom 104 is attached to the front center part so that it can be raised and lowered. An arm 105 is attached to the tip of the boom 104 so that it can be bent up and down. A bucket 106 is attached to the tip of the arm 105 so that it can be bent up and down.

A gyro sensor 110 is attached to the front left side of the cab 103. In other words, the gyro sensor 110 is attached to the upper rotating body 102 at a position that is as far away as possible from the center of rotation C1. The gyro sensor 110 is a sensor that can detect the tilt angle, tilt direction, rotation position, and rotation angular velocity of the cab 103 (lower traveling body 101, upper rotating body 102). The tilt direction refers to the upward or downward direction of the tilt.

Hereinafter, the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106 will be collectively referred to as the joint components of the electric construction machine 100. Therefore, the electric construction machine 100 in Figures 1 and 2 is a construction machine having five joint components. Note that the lower traveling body 101 constitutes a traveling part that can travel on the ground, the upper rotating body 102 constitutes a rotating part that can rotate relative to the traveling part, and the boom 104, the arm 105, and the bucket 106 are attached to the rotating part and constitute a working part that performs work.

Strictly speaking, the joint components are the parts that rotate when the lower running body 101, upper rotating body 102, boom 104, arm 105, and bucket 106 are driven, and are indicated by 101A, 102A, 104A, 105A, and 106A in FIG. 1, respectively. The joint component 101A of the lower running body 101 is the front and rear wheels that form the endless track, the joint component 102A of the upper rotating body 102 is a rotating shaft attached to the lower running body 101, the joint component 104A of the boom 104 is a hoisting shaft attached to the upper rotating body 102, the joint component 105A of the arm 105 is a bending shaft attached to the tip of the boom 104, and the joint component 106A of the bucket 106 is a bending shaft attached to the tip of the arm 105. Hereinafter, unless otherwise specified, the reference numerals 101A, 102A, 104A, 105A, and 106A will not be used, but 101, 102, 104, 105, and 106 will be used. For example, the expressions "lower running body 101" and/or "articulated component 101" will refer to articulated component 101A depending on the context.

3 shows a first configuration example of the driving device 1 of the electric construction machine 100. The driving device 1 drives the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106, which are joint components of the electric construction machine 100, based on the DC voltage or DC power generated by the battery 10 as a DC power source. Note that an AC power source that generates AC power may be provided instead of the battery 10 as a DC power source that generates DC power. Each joint component of the electric construction machine 100 is provided with an actuator as a drive unit that drives each of them. Hereinafter, the pair of traveling body actuators 21A and 21B that drive the lower traveling body 101 to travel, the rotating body actuator 22 that drives the upper rotating body 102 to rotate, the boom actuator 24 that drives the boom 104 to rise and fall, the arm actuator 25 that drives the arm 105 to bend, and the bucket actuator 26 that drives the bucket 106 to bend are collectively referred to as actuator 2.

Each actuator 2 includes a converter, an inverter, and a motor. The pair of traveling body actuators 21A and 21B includes converters 211A and 211B, inverters 221A and 221B, and motors 231A and 231B. The rotating body actuator 22 includes a converter 212, an inverter 222, and a motor 232. The boom actuator 24 includes a converter 214, an inverter 224, and a motor 234. The arm actuator 25 includes a converter 215, an inverter 225, and a motor 235. The bucket actuator 26 includes a converter 216, an inverter 226, and a motor 236. Hereinafter, converters 211A, 211B, 212, 214, 215, and 216 are collectively referred to as converter 210, inverters 221A, 221B, 222, 224, 225, and 226 are collectively referred to as inverter 220, and motors 231A, 231B, 232, 234, 235, and 236 are collectively referred to as motor 230.

The converter 210 receives AC power converted from DC power from the battery 10 as described below, except for the converter 212 of the rotating body actuator 22 that is provided on the upper rotating body 102 together with the battery 10. The converter 212 of the rotating body actuator 22 receives DC power from the battery 10 without being converted by the DC/AC converter 121 or DC/AC converter 131 described below. Each converter 210 converts the input AC or DC power into DC power that can operate each inverter 220 in the subsequent stage. The inverter 220 generates three-phase AC power that rotates the motor 230 in the subsequent stage based on the DC power input from the converter 210. The motor 230 generates rotational power based on the three-phase AC power input from the inverter 220 to drive the corresponding joint component.

The battery 10 is connected to the DC voltage bus 31 via the charge/discharge converter 11. The charge/discharge converter 11 is a bidirectional DC/DC converter that controls the charging and discharging of the battery 10 and converts the DC voltage. When the battery 10 is discharged, the DC voltage resulting from the discharge of the battery 10 is converted by the charge/discharge converter 11 into a predetermined DC voltage on the DC voltage bus 31. When the battery 10 is charged, the predetermined DC voltage on the DC voltage bus 31 is converted by the charge/discharge converter 11 into a DC voltage that can charge the battery 10. The predetermined DC voltage on the DC voltage bus 31 can be set arbitrarily, but is preferably set to a high voltage of, for example, about 200V to 400V.

Of the above components, the battery 10, charge/discharge converter 11, DC voltage bus 31, and rotating body actuator 22 are provided in the upper rotating body 102, which is the main body of the electric construction machine 100 (the components above the dashed line in FIG. 3 are included in the upper rotating body 102). Since the above-mentioned rotating body actuator 22 is connected to the DC voltage bus 31, power for driving the upper rotating body 102 to rotate is supplied from the DC voltage bus 31. In addition, a working unit power supply mechanism 12 that supplies power to a working unit composed of a boom 104, an arm 105, and a bucket 106, and a traveling body power supply mechanism 13 that supplies power to the lower traveling body 101 are provided so as to branch off from the DC voltage bus 31.

The working unit power supply mechanism 12 includes a DC/AC converter 121, a boom transmission unit 122, an arm transmission unit 123, and a bucket transmission unit 124. The DC/AC converter 121 constitutes a (DC-AC) conversion unit that converts the DC power generated by the battery 10 into AC power. Specifically, the DC/AC converter 121 connected to the DC voltage bus 31 in the upper rotating body 102 converts the DC voltage supplied from the DC voltage bus 31 into an AC voltage with a frequency of 1 kHz or more. The frequency of AC power from a commercial power source is generally less than 100 Hz, but at such a low frequency, the coil constituting the non-contact transmission unit described below becomes large. Therefore, in this embodiment, a frequency of 1 kHz or more, which is higher than the commercial power source, is adopted to reduce the size of the coil and form a compact non-contact transmission unit in each joint component of the electric construction machine 100 with limited space. In addition, when an AC power supply that generates AC power is provided instead of battery 10 that generates DC power, an AC/AC converter that converts the AC power (e.g., less than 100 Hz) generated by the AC power supply into AC power having a higher frequency (e.g., 1 kHz or higher) is provided as a conversion unit instead of DC/AC converter 121.

The boom transmission unit 122, the arm transmission unit 123, and the bucket transmission unit 124 constitute a non-contact transmission unit that transmits AC power converted by the DC/AC converter 121 in a non-contact manner to the boom 104, the arm 105, and the bucket 106, which are joint components of the electric construction machine 100. Specifically, the boom transmission unit 122 transmits power in a non-contact manner to the boom actuator 24 and the arm transmission unit 123, the arm transmission unit 123 transmits power in a non-contact manner to the arm actuator 25 and the bucket transmission unit 124, and the bucket transmission unit 124 transmits power in a non-contact manner to the bucket actuator 26. The boom transmission unit 122, the arm transmission unit 123, and the bucket transmission unit 124 are connected in series by an AC voltage bus 32 that transmits AC power supplied from the DC/AC converter 121. In this way, by connecting the boom transmission unit 122, the arm transmission unit 123, and the bucket transmission unit 124 in series, there is no need to provide a separate DC/AC converter 121 for each transmission unit, thereby simplifying the configuration of the drive unit 1.

The boom transmission unit 122 is composed of multiple coils stored inside a connecting part such as a swivel that connects the boom 104 and the upper rotating body 102 to be relatively rotatable around a rotation axis (104A in FIG. 1) in the left-right direction. Specifically, the boom transmission unit 122 is composed of a primary coil 1221 connected to the DC/AC converter 121 on the upper rotating body 102 side, a secondary coil 1222 connected to the AC voltage bus 32 on the arm 105 side, and a tertiary coil 1223 connected to the boom actuator 24. Note that all or some of the coils of the boom transmission unit 122 and the DC/AC converter 121 in the front stage and/or the converter 214 in the rear stage (and further the inverter 224) may be configured as an integrated transformer unit or non-contact transmission unit.

The primary coil 1221, the secondary coil 1222, and the tertiary coil 1223 are magnetically coupled to each other. The AC power supplied from the DC/AC converter 121 to the primary coil 1221 is transmitted contactlessly to the arm 105 side and/or the boom actuator 24 by the secondary coil 1222 and/or the tertiary coil 1223 magnetically coupled to the primary coil 1221. In this manner, the boom actuator 24 as the drive unit of the boom 104 drives the boom 104 based on the AC power transmitted contactlessly by the primary coil 1221 and the tertiary coil 1223 in the boom transmission unit 122 as the contactless transmission unit. Note that a magnetic material or the like may be inserted into the gaps between the primary coil 1221, the secondary coil 1222, and the tertiary coil 1223 to increase the power transmission efficiency.

In addition, regenerative power generated during deceleration of the motor 234 of the boom actuator 24 is supplied to the tertiary coil 1223 via the inverter 224 and the converter 214, and is transmitted in a non-contact manner to the upper rotating body 102 side and/or the arm 105 side by the primary coil 1221 and/or the secondary coil 1222 magnetically coupled thereto. As described below, regenerative power generated during deceleration of the motor 235 of the arm actuator 25 and/or the motor 236 of the bucket actuator 26 is supplied to the secondary coil 1222 via the AC voltage bus 32, and is transmitted in a non-contact manner to the upper rotating body 102 side and/or the boom actuator 24 by the primary coil 1221 and/or the tertiary coil 1223 magnetically coupled thereto. In addition, the magnetic coupling between each coil 1221, 1222, 1223 may be such that the magnitude of the AC voltage transmitted non-contactingly is kept constant, or it may be such as a transformer or transformer that changes the magnitude of the AC voltage transmitted non-contactingly.

The arm transmission unit 123 is composed of multiple coils stored inside a connecting part such as a swivel that connects the arm 105 and the boom 104 to be relatively rotatable around a rotation axis (105A in FIG. 1) in the left-right direction. Specifically, the arm transmission unit 123 is composed of a primary coil 1231 connected to the AC voltage bus 32 on the boom 104 side, a secondary coil 1232 connected to the AC voltage bus 32 on the bucket 106 side, and a tertiary coil 1233 connected to the arm actuator 25.

The primary coil 1231, the secondary coil 1232, and the tertiary coil 1233 are magnetically coupled to each other. The AC power supplied from the secondary coil 1222 of the boom transmission unit 122 to the primary coil 1231 via the AC voltage bus 32 is transmitted contactlessly to the bucket 106 side and/or the arm actuator 25 by the secondary coil 1232 and/or the tertiary coil 1233 magnetically coupled to the primary coil 1231. In this way, the arm actuator 25 as the drive unit of the arm 105 drives the arm 105 based on the AC power transmitted contactlessly by the primary coil 1231 and the tertiary coil 1233 in the arm transmission unit 123 as the contactless transmission unit. Note that a magnetic material or the like may be inserted into the gaps between the primary coil 1231, the secondary coil 1232, and the tertiary coil 1233 to increase the power transmission efficiency.

In addition, the regenerative power generated during deceleration of the motor 235 of the arm actuator 25 is supplied to the tertiary coil 1233 via the inverter 225 and the converter 215, and is transmitted in a non-contact manner to the boom 104 side and/or the bucket 106 side by the primary coil 1231 and/or the secondary coil 1232 magnetically coupled thereto. As described later, the regenerative power generated during deceleration of the motor 236 of the bucket actuator 26 is supplied to the secondary coil 1232 via the AC voltage bus 32, and is transmitted in a non-contact manner to the boom 104 side and/or the arm actuator 25 by the primary coil 1231 and/or the tertiary coil 1233 magnetically coupled thereto. The magnetic coupling between the coils 1231, 1232, and 1233 may be such that the magnitude of the AC voltage transmitted in a non-contact manner is kept constant, or may be such as a transformer or a transformer that changes the magnitude of the AC voltage transmitted in a non-contact manner.

The bucket transmission unit 124 is composed of multiple coils stored inside a connecting part such as a swivel that connects the bucket 106 and the arm 105 to be relatively rotatable around a rotation axis (106A in FIG. 1) in the left-right direction. Specifically, the bucket transmission unit 124 is composed of a primary coil 1241 connected to the AC voltage bus 32 on the arm 105 side, and a secondary coil 1242 connected to the bucket actuator 26.

The primary coil 1241 and the secondary coil 1242 are magnetically coupled to each other. The AC power supplied from the secondary coil 1232 of the arm transmission unit 123 to the primary coil 1241 via the AC voltage bus 32 is transmitted contactlessly to the bucket actuator 26 by the secondary coil 1242 magnetically coupled to the primary coil 1241. In this way, the bucket actuator 26 as the drive unit of the bucket 106 drives the bucket 106 based on the AC power transmitted contactlessly by the primary coil 1241 and the secondary coil 1242 in the bucket transmission unit 124 as the contactless transmission unit. Note that a magnetic material or the like may be inserted into the gap between the primary coil 1241 and the secondary coil 1242 to increase the power transmission efficiency.

In addition, regenerative power generated when the motor 236 of the bucket actuator 26 is decelerated is supplied to the secondary coil 1242 via the inverter 226 and the converter 216, and is transmitted in a non-contact manner to the arm 105 side by the primary coil 1241 magnetically coupled thereto. The magnetic coupling between the coils 1241, 1242 may be such that the magnitude of the AC voltage transmitted in a non-contact manner is kept constant, or may be such as a transformer or a transformer that changes the magnitude of the AC voltage transmitted in a non-contact manner.

The traveling body power supply mechanism 13 includes a DC/AC converter 131, a step-down transmission unit 132, and a pair of step-up transmission units 133A and 133B. The DC/AC converter 131 constitutes a (DC-AC) conversion unit that converts the DC power generated by the battery 10 into AC power. Specifically, the DC/AC converter 131 connected to the DC voltage bus 31 in the upper rotating body 102 converts the DC voltage supplied from the DC voltage bus 31 into an AC voltage with a frequency of 1 kHz or more. When an AC power source that generates AC power is provided instead of the battery 10 that generates DC power, an AC/AC converter that converts the AC power (e.g., less than 100 Hz) generated by the AC power source into AC power having a higher frequency (e.g., 1 kHz or more) is provided as a conversion unit instead of the DC/AC converter 131. The step-down transmission unit 132 and the pair of step-up transmission units 133A and 133B constitute a non-contact transmission unit that transmits AC power converted by the DC/AC converter 131 in the lower running body 101, which is a joint component of the electric construction machine 100, and a lower running body transmission unit that transmits power non-contactly to the running body actuators 21A and 21B, which are the drive units of the lower running body 101.

The step-down transmission unit 132 is composed of multiple coils stored inside a connecting part such as a swivel that connects the lower traveling body 101 and the upper rotating body 102 so that they can rotate relatively around a vertical rotation axis (rotation axis 102A in FIG. 1). Specifically, the step-down transmission unit 132 is composed of a primary coil 1321 connected to the DC/AC converter 131 on the upper rotating body 102 side, and a secondary coil 1322 connected in parallel to a pair of step-up transmission units 133A and 133B on the lower traveling body 101 side. Note that all or some of the coils of the step-down transmission unit 132 and the DC/AC converter 131 at the previous stage may be configured as an integrated transformer unit or non-contact transmission unit.

The primary coil 1321 and the secondary coil 1322 are magnetically coupled to each other. The AC power supplied from the DC/AC converter 131 to the primary coil 1321 is transmitted to the lower traveling body 101 side in a non-contact manner by the secondary coil 1322 magnetically coupled to the primary coil 1321. As described later, regenerative power generated during deceleration of the motors 231A and/or 231B of the traveling body actuators 21A and/or 21B is supplied to the secondary coil 1322 via the boost transmission unit 133A and/or 133B, and transmitted to the upper rotating body 102 side in a non-contact manner by the primary coil 1321 magnetically coupled thereto. A magnetic material or the like may be inserted into the gap between the primary coil 1321 and the secondary coil 1322 to increase the power transmission efficiency.

The step-down transmission unit 132 is configured as a transformer or transformer that changes the magnitude of the AC voltage transmitted contactlessly depending on the difference in the number of turns of the primary coil 1321 and the secondary coil 1322, and steps down the AC voltage supplied from the DC/AC converter 131 on the upper rotating body 102 side and transmits it contactlessly to the lower traveling body 101 side. As described above, the DC voltage of the DC voltage bus 31 to which the DC/AC converter 131 is connected is, for example, about 200V to 400V, but is converted to a low-voltage AC voltage of about 40V to 60V by the step-down transmission unit 132. The step-down transmission unit 132 is installed in the rotating part (rotating part) between the upper rotating body 102 and the lower traveling body 101, and safety can be ensured even if a leakage current occurs due to the adhesion of soil containing moisture or water, because the voltage is lowered by the step-down transmission unit 132. It should be noted that the boom transmission unit 122 in the working unit power supply mechanism 12, which is less likely to come into contact with a person than the step-down transmission unit 132, does not need to perform a significant step-down like the step-down transmission unit 132. For this reason, the AC voltage of the AC voltage bus 32 in the working unit power supply mechanism 12 becomes higher than the AC voltage stepped down by the step-down transmission unit 132.

The pair of boost transmission units 133A and 133B are provided in parallel corresponding to a pair of left and right lower traveling bodies 101 such as crawlers. Hereinafter, they will be collectively referred to as boost transmission unit 133. Similarly, the pair of traveling body actuators 21A and 21B will be collectively referred to as traveling body actuator 21, the pair of converters 211A and 211B will be collectively referred to as converter 211, the pair of inverters 221A and 221B will be collectively referred to as inverter 221, and the pair of motors 231A and 231B will be collectively referred to as motor 231.

The boost transmission unit 133 is composed of multiple coils stored inside the left and right lower running bodies 101. Specifically, the boost transmission unit 133 is composed of a primary coil 1331 connected to the secondary coil 1322 of the step-down transmission unit 132, and a secondary coil 1332 connected to the running body actuator 21. Note that all or some of the coils of the boost transmission unit 133 and the downstream converter 211 (and further inverter 221) may be configured as an integrated transformer unit or non-contact transmission unit.

The primary coil 1331 and the secondary coil 1332 are magnetically coupled to each other. The AC power supplied from the secondary coil 1322 of the step-down transmission unit 132 to the primary coil 1331 is transmitted to the traveling body actuator 21 in a non-contact manner by the secondary coil 1332 magnetically coupled to the primary coil 1331. In addition, regenerative power generated during deceleration of the motor 231 of the traveling body actuator 21 is supplied to the secondary coil 1332 via the inverter 221 and the converter 211, and is transmitted in a non-contact manner to the secondary coil 1322 of the step-down transmission unit 132 and/or the primary coil 1331 of the other step-up transmission unit 133 by the primary coil 1331 magnetically coupled thereto. A magnetic material or the like may be inserted into the gap between the primary coil 1331 and the secondary coil 1332 to increase the power transmission efficiency.

The step-up transmission unit 133 is configured as a transformer or transformer that changes the magnitude of the AC voltage transmitted contactlessly depending on the difference in the number of turns of the primary coil 1331 and the secondary coil 1332, and steps up the AC voltage supplied from the secondary coil 1322 of the step-down transmission unit 132 and transmits it contactlessly to the running body actuator 21. As described above, the AC voltage stepped down to about 40V to 60V by the step-down transmission unit 132 is stepped up by the step-up transmission unit 133 to a level at which the converter 211 of the running body actuator 21 can operate. As described above, the running body actuator 21 as the drive unit of the lower running body 101 drives the lower running body 101 based on the AC power transmitted contactlessly by the step-down transmission unit 132 and the step-up transmission unit 133 as contactless transmission units.

The regenerative power recovered by the actuators 2 of each joint component is used to drive the other joint components by the actuators 2, and is also charged to a capacitor 14 serving as a regenerative power charging unit, which is composed of an electric double-layer capacitor (EDLC) or the like connected to the DC voltage bus 31. As will be described later with respect to the power control device of this embodiment, the regenerative power recovered by the boom actuator 24, arm actuator 25, and bucket actuator 26, which are interconnected by the AC voltage bus 32, is preferentially consumed by these actuator groups, and is returned to the upper rotating body 102 side only if there is a surplus.

Specifically, the surplus of the regenerative power recovered by the bucket actuator 26 that is not consumed by either the boom actuator 24 or the arm actuator 25 is converted to AC power by the converter 216 and then non-contact-transmitted to the DC/AC converter 121 of the upper rotating body 102 via the bucket transmission unit 124, the arm transmission unit 123, and the boom transmission unit 122. The surplus of the regenerative power recovered by the arm actuator 25 that is not consumed by either the boom actuator 24 or the bucket actuator 26 is converted to AC power by the converter 215 and then non-contact-transmitted to the DC/AC converter 121 of the upper rotating body 102 via the arm transmission unit 123 and the boom transmission unit 122. The surplus of the regenerative power recovered by the boom actuator 24 that is not consumed by either the arm actuator 25 or the bucket actuator 26 is converted to AC power by the converter 214 and then non-contact-transmitted to the DC/AC converter 121 of the upper rotating body 102 via the boom transmission unit 122.

The DC/AC converter 121 that receives the surplus regenerative power from at least one of the boom actuator 24, the arm actuator 25, and the bucket actuator 26 converts the AC power into DC power and supplies it to the charge/discharge circuit 141 that charges the capacitor 14. FIG. 4 shows an example of the configuration of the charge/discharge circuit 141. The charge/discharge circuit 141 includes a high-potential transistor 142H connected to the high-potential line 31H of the DC voltage bus 31, a low-potential transistor 142L connected to the low-potential line 31L of the DC voltage bus 31, and a step-up/step-down reactor 144 connected in series with the capacitor 14 between the connection point 143 of the high-potential transistor 142H and the low-potential transistor 142L and the low-potential line 31L. The charge/discharge circuit 141 controls the charging and discharging of the capacitor 14 and converts the DC voltage by the switching operation of the high-potential transistor 142H and the low-potential transistor 142L.

The regenerative power converted to DC power by the DC/AC converter 121 may be used to charge the battery 10 via the charge/discharge converter 11, or may be supplied to other actuators (the rotating body actuator 22 and/or the running body actuator 21) without being charged. The power stored in the capacitor 14 can be discharged by the charge/discharge circuit 141 and supplied to each actuator 2.

Similarly, the regenerative power recovered by the pair of running body actuators 21A, 21B is preferentially consumed by these actuator groups, and is returned to the upper rotating body 102 only if there is a surplus. Specifically, the surplus of the regenerative power recovered by one running body actuator 21 that is not consumed by the other running body actuator 21 is converted to AC power by the converter 211 and then transmitted non-contact to the DC/AC converter 131 of the upper rotating body 102 via the step-up transmission unit 133 and the step-down transmission unit 132.

The DC/AC converter 131, which receives the surplus regenerative power from at least one of the pair of traveling body actuators 21A and 21B, converts the AC power into DC power and supplies it to the charge/discharge circuit 141 that charges the capacitor 14. The regenerative power converted into DC power by the DC/AC converter 131 may be used to charge the battery 10 via the charge/discharge converter 11, or may be supplied to other actuators (the rotating body actuator 22, the boom actuator 24, the arm actuator 25, the bucket actuator 26, etc.) without being charged. The regenerative power recovered by the rotating body actuator 22 is converted into DC power by the converter 212 and then supplied to the charge/discharge circuit 141 that charges the capacitor 14, the charge/discharge converter 11 that charges the battery 10, and other actuators (the traveling body actuator 21, the boom actuator 24, the arm actuator 25, the bucket actuator 26, etc.).

According to the above drive device 1, the step-down transmission unit 132, boom transmission unit 122, arm transmission unit 123, and bucket transmission unit 124 are provided as non-contact transmission units in the lower traveling body 101, boom 104, arm 105, and bucket 106 among the joint components of the electric construction machine 100, so that AC power can be transmitted non-contact without interfering with the smooth operation of these joint components. In addition, since each non-contact transmission unit can be simply configured with multiple coils, it is possible to prevent the joint components from becoming complicated and large in size compared to a configuration in which wiring for transmitting DC power is stored in the joint components as in Patent Document 1.

Figure 5 shows a second configuration example of the drive unit 1 of the electric construction machine 100. Components similar to those in the first configuration example of Figure 3 are given the same reference numerals and duplicated explanations are omitted. In the second configuration example, a DC/AC converter 15 is provided in association with the battery 10 as a DC/AC conversion unit that converts the DC power generated by the battery 10 into AC power.

When the battery 10 is discharged, the DC power discharged from the battery 10 is converted by the DC/AC converter 15 into AC power with a frequency of 1 kHz or more and supplied to the AC voltage bus 33. When the battery 10 is charged, the AC power in the AC voltage bus 33 is converted by the DC/AC converter 15 into DC power to charge the battery 10. The AC voltage bus 33, to which AC power is supplied from the DC/AC converter 15, supplies AC power with a frequency of 1 kHz or more to the rotating body actuator 22, the working unit power supply mechanism 12, and the traveling body power supply mechanism 13.

In the first configuration example of Fig. 3, DC power is input from the DC voltage bus 31 to the converter 212 of the rotating body actuator 22, but in the second configuration example of Fig. 5, AC power is input from the AC voltage bus 33 to the converter 212 of the rotating body actuator 22. The converter 212 of the rotating body actuator 22 converts the input AC power into DC power that can operate the inverter 222 in the downstream stage.

The working unit power supply mechanism 12 is similar to the first configuration example, except that the DC/AC converter 121 in Fig. 3 is not provided. The function of the DC/AC converter 121 in Fig. 3 is performed by the DC/AC converter 15 in Fig. 5. That is, the DC/AC converter 15 supplies AC power to the primary coil of the boom transmission unit 122 via the AC voltage bus 33.

The traveling body power supply mechanism 13 is the same as the first configuration example, except that the DC/AC converter 131 in Fig. 3 is not provided. The function of the DC/AC converter 131 in Fig. 3 is performed by the DC/AC converter 15 in Fig. 5. That is, the DC/AC converter 15 supplies AC power to the primary coil of the step-down transmission unit 132 via the AC voltage bus 33.

In the second configuration example of Figure 5, an AC/DC converter 16 is provided in front of the capacitor 14 and charge/discharge circuit 141 that constitute the regenerative power charging unit. The AC/DC converter 16 converts the AC power of the AC voltage bus 33 into DC power that the charge/discharge circuit 141 uses to charge the capacitor 14. When discharging the capacitor 14, the DC power output by the charge/discharge circuit 141 is converted into AC power by the AC/DC converter 16 and supplied to the AC voltage bus 33.

Figure 6 shows a third configuration example of the drive device 1 of the electric construction machine 100. Components similar to those in the first configuration example of Figure 3 are given the same reference numerals and duplicated explanations are omitted. In the third configuration example, the charge/discharge converter 11 functions as an AC superposition unit that superimposes AC power with a frequency of 1 kHz or more on the DC power generated by the battery 10. Figure 7 shows a schematic diagram of the change over time t in the voltage V supplied by the charge/discharge converter 11 to the DC/AC voltage bus 34. "DC" indicates the DC voltage generated by the battery 10, and the voltage V obtained by superimposing the AC voltage indicated by "AC" on this by the charge/discharge converter 11 is supplied to the DC/AC voltage bus 34.

The converter 212 and the charge/discharge circuit 141 of the rotating body actuator 22, which are directly connected to the DC/AC voltage bus 34, operate in the same manner as the first configuration example of Figure 3, based mainly on the DC component of the voltage V supplied from the DC/AC voltage bus 34.

In place of the DC/AC converter 121 in Fig. 3, the working unit power supply mechanism 12 includes a DC removal filter 125 as a DC removal filter and an AC/AC converter 126 as an AC conversion unit. The DC removal filter 125 is connected to the output of the charge/discharge converter 11 as an AC superposition unit, and performs a function equivalent to that of the DC/AC converter 121 as a DC/AC conversion unit by removing DC power and passing AC power. In the example of Fig. 7, the DC component "DC" is removed by the DC removal filter 125, and the AC component "AC" passes through the DC removal filter 125.

The AC power that has passed through the DC removal filter 125 may be supplied directly to the primary coil of the boom transmission unit 122, but in the example of FIG. 6, an AC/AC converter 126 for increasing the efficiency of non-contact transmission in the boom transmission unit 122 is provided together with a resonant circuit (not shown). The AC/AC converter 126 converts the frequency of the AC power that has passed through the DC removal filter 125 and supplies it to the boom transmission unit 122 as a non-contact transmission unit. Specifically, the AC/AC converter 126 increases the frequency of the AC power, and transitions the AC power to a high frequency band where the efficiency of non-contact transmission in the boom transmission unit 122 is increased. The AC power whose frequency has been increased by the AC/AC converter 126 is supplied to the primary coil of the boom transmission unit 122. The AC/AC converter 126 for increasing the efficiency of non-contact transmission in the boom transmission unit 122 may be provided in the first configuration example of FIG. 3 or the second configuration example of FIG. 5.

The traveling body power supply mechanism 13 includes a DC removal filter 134 as a DC removal filter and an AC/AC converter 135 as an AC conversion unit, instead of the DC/AC converter 131 in Fig. 3. The DC removal filter 134 is connected to the output of the charge/discharge converter 11 as an AC superposition unit, and performs a function equivalent to that of the DC/AC converter 131 as a DC/AC conversion unit by removing DC power and passing AC power. In the example of Fig. 7, the DC component "DC" is removed by the DC removal filter 134, and the AC component "AC" passes through the DC removal filter 134.

The AC power that has passed through the DC removal filter 134 may be supplied directly to the primary coil of the step-down transmission unit 132, but in the example of FIG. 6, an AC/AC converter 135 for increasing the efficiency of non-contact transmission in the step-down transmission unit 132 is provided together with a resonant circuit (not shown). The AC/AC converter 135 converts the frequency of the AC power that has passed through the DC removal filter 134 and supplies it to the step-down transmission unit 132 as a non-contact transmission unit. Specifically, the AC/AC converter 135 increases the frequency of the AC power, and transitions the AC power to a high frequency band where the efficiency of non-contact transmission in the step-down transmission unit 132 is increased. The AC power whose frequency has been increased by the AC/AC converter 135 is supplied to the primary coil of the step-down transmission unit 132. The AC/AC converter 135 for increasing the efficiency of non-contact transmission in the step-down transmission unit 132 may be provided in the first configuration example of FIG. 3 or the second configuration example of FIG. 5.

Figure 8 shows an example configuration of the power control device 4 of the electric construction machine 100. The power control device 4 includes a power demand acquisition unit 41, a supplyable power acquisition unit 42, a power comparison unit 43, a determination unit 44, an identification unit 45, and a drive information acquisition unit 47.

The power demand acquisition unit 41 acquires the motor rotation speed N and current command values iq and id of each actuator 2 as information indicating the power demand of each actuator 2 of the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106. This information may be transmitted to the power demand acquisition unit 41 by a communication device (not shown) built into each actuator 2 using short-range wireless communication technology or the like, or the AC power supplied to each actuator 2 may be modulated as a carrier wave and transmitted to the power demand acquisition unit 41 via the non-contact transmission units 122, 123, 124, 132, and 133. FIG. 9 shows the motor current command value in each actuator 2 in the dq coordinate system. In the dq coordinate system, the d-axis current id does not contribute to the generation of torque in the motor, and when id=0, iq·N, which is the q-axis current iq multiplied by the rotation speed N, becomes the power demand of each actuator 2. On the other hand, since it is necessary to flow a negative d-axis current id when performing field weakening control to reduce the back electromotive force caused by the field magnet when the motor rotates at high speed, the power demand acquisition unit 41 calculates the power demand of each actuator 2 taking into consideration not only the q-axis current iq but also the d-axis current id. Note that the power demand acquisition unit 41 may estimate the power demand of each actuator 2 based on the operation by the operator of the operation unit 40 of the electric construction machine 100, i.e., the operation command for each actuator 2.

The available power acquisition unit 42 acquires the power that the power control device 4 can supply to each actuator 2. The available power of the power control device 4 is the sum of the charge amount or dischargeable amount of the battery 10, the charge amount or dischargeable amount of the capacitor 14, and the regenerative power recovered by each actuator 2. As information indicating the charge amount or dischargeable amount of the battery 10, the available power acquisition unit 42 acquires the SOC (State Of Charge), which is the charging rate of the battery 10, and the dischargeable amount. As information indicating the charge amount or dischargeable amount of the capacitor 14, the available power acquisition unit 42 acquires the SOC, which is the charging rate of the capacitor 14. The regenerative power recovered by each actuator 2 is roughly divided into working unit regenerative power recovered by actuators 24, 25, 26 of the working unit (boom 104, arm 105, bucket 106), traveling body regenerative power recovered by traveling body actuators 21A, 21B of the lower traveling body 101, and rotating body regenerative power recovered by actuator 22 of the upper rotating body 102. As will be described later, the working unit regenerative power is preferentially consumed by the working unit actuators 24, 25, 26, and the traveling body regenerative power is preferentially consumed by the traveling body actuators 21A, 21B of the lower traveling body 101.

The power comparison unit 43 compares the total power demand of each actuator 2 acquired by the power demand acquisition unit 41 with the power supplyable power of the power control device 4 acquired by the power supplyable power acquisition unit 42. When the total power demand of each actuator 2 is greater than the power supplyable power of the power control device 4, the determination unit 44 determines the actuator 2 to which power less than the demand power is supplied according to the operation of the electric construction machine 100 identified by the identification unit 45 and/or the moment of inertia of the working part acquired by the moment of inertia acquisition unit 46. The determination unit 44 may determine the power to be supplied to each actuator 2 according to the operation of the electric construction machine 100 identified by the identification unit 45, regardless of the magnitude relationship between the total power demand of each actuator 2 and the power supplyable power of the power control device 4. In addition, when the total power demand of each actuator 2 is greater than the power supplyable power of the power control device 4, the determination unit 44 determines to supply power less than the demand power to the actuator 2 that requires less power according to the operation of the electric construction machine 100 identified by the identification unit 45 among the multiple actuators 2. A specific example of the power supply amount determination process performed by the determination unit 44 will be described later.

The available power of the power control device 4 acquired by the available power acquisition unit 42 is supplied to each actuator 2 according to the distribution determined by the determination unit 44. At this time, the surplus regenerative power recovered by each actuator 2 is charged to the battery 10 and/or the capacitor 14 by the charge/discharge converter 11 and/or the charge/discharge circuit 141. In addition, the DC/AC converter 121, which is responsible for bidirectional power transmission between the upper rotating body 102 and the working unit, converts DC power from the upper rotating body 102 side, such as the battery 10 and the capacitor 14, into AC power and supplies it to the actuators 24, 25, and 26 of the working unit, and converts the surplus regenerative power recovered by the actuators 24, 25, and 26 of the working unit from AC to DC and supplies or charges the battery 10 and the capacitor 14 of the upper rotating body 102. Similarly, the DC/AC converter 131, which is responsible for bidirectional power transmission between the upper rotating body 102 and the lower traveling body 101, converts DC power from the upper rotating body 102 side, such as the battery 10 and the capacitor 14, into AC power and supplies it to the actuators 21A and 21B of the lower traveling body 101, and also converts surplus regenerative power recovered by the actuators 21A and 21B of the lower traveling body 101 from AC to DC and supplies or charges the battery 10 and the capacitor 14 of the upper rotating body 102. In addition, the determination unit 44 determines the allocation of power (including regenerative power) between the boom transmission unit 122, the arm transmission unit 123, and the bucket transmission unit 124, which are connected in series. Similarly, the determination unit 44 determines the allocation of power (including regenerative power) between the two step-up transmission units 133A and 133B connected in series.

The drive information acquisition unit 47 acquires drive information for each actuator 2 of each joint component of the electric construction machine 100, i.e., the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106. Examples of drive information for each actuator 2 include an operation command by an operator received by the operation unit 40 of the electric construction machine 100, operation commands such as a voltage command value and a current command value applied to the motor in each actuator 2 generated based on the operation command, measurement data of operation parameters such as the rotation speed, current, and torque of the motor in each actuator 2, and measurement data of an acceleration sensor provided in each joint component. The identification unit 45 identifies the operation performed by each joint component of the electric construction machine 100 based on the drive information acquired by the drive information acquisition unit 47 and the correspondence between the operation and the drive information stored in a storage unit (not shown) such as a memory. The identification unit 45 may identify the operation of the electric construction machine 100 by referring to a table in which the driving information acquired by the driving information acquisition unit 47 is associated with the operation of the electric construction machine 100, or may identify the operation of the electric construction machine 100 through artificial intelligence that has been subjected to machine learning using comprehensive teacher data corresponding to such a table. The inertia moment acquisition unit 46 provided in the identification unit 45 includes a weight acquisition unit 461 that acquires the weight of the transported object transported by the bucket 106 and a distance acquisition unit 462 that acquires the distance of the bucket 106 from the rotation axis of the upper rotating body 102, and acquires the inertia moment around the rotation axis of the working unit including the transported object. Note that the weight or mass of the working unit (boom 104, arm 105, bucket 106) itself required for calculating the inertia moment of the working unit is stored in advance in the inertia moment acquisition unit 46.

Figure 10 is a flowchart showing an example of power control processing by the power control device 4. In the explanation of the flowchart, "S" means a step or process. In S1, the power demand acquisition unit 41 acquires or calculates the power demand of each actuator 2 of the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106. In S2, the power supply acquisition unit 42 acquires the power that the power control device 4 can supply to each actuator 2. In S3, the power comparison unit 43 compares the total power demand of each actuator 2 acquired in S1 with the power supplyable power of the power control device 4 acquired in S2. If the result of the power comparison in S3 shows that the total power demand of each actuator 2 is greater than the power supplyable power of the power control device 4 (Yes in S4), the process proceeds to S5, and if the total power demand of each actuator 2 is equal to or less than the power supplyable power of the power control device 4 (No in S4), the process proceeds to S8.

In S5, the drive information acquisition unit 47 acquires drive information of the actuators 2 of each joint component of the electric construction machine 100, and the identification unit 45 identifies the operation of the electric construction machine 100 by the lower traveling body 101, the upper rotating body 102, the boom 104, the arm 105, and the bucket 106 based on the acquired drive information. In S6, the inertia moment acquisition unit 46 acquires the inertia moment around the rotation axis of the working unit including the transported object based on the weight of the transported object of the bucket 106 acquired by the weight acquisition unit 461 and the distance of the bucket 106 from the rotation axis acquired by the distance acquisition unit 462. In S7, the determination unit 44 determines the power to be supplied to each actuator 2 according to the operation of the electric construction machine 100 identified in S5 and/or the inertia moment of the working unit acquired in S6. For example, the determination unit 44 determines, in accordance with the weight of the transported load acquired in S6, that the power to be supplied to the actuator 2 of the upper rotating body 102, the boom 104, the arm 105, and the bucket 106 that bears a smaller weight or load is smaller than the power to be supplied to the actuator 2 that bears a larger weight or load. Also, the determination unit 44 increases the power to be supplied to the rotating body actuator 22 as the distance acquired in S6 increases.

In S8, the available power of the power control device 4 obtained in S2 is supplied or allocated to each actuator 2 via the charge/discharge converter 11, charge/discharge circuit 141, DC/AC converters 121, 131, etc. If the answer to S4 is No, in principle, power is supplied to each actuator 2 according to the power demand obtained in S1. If the answer to S4 is Yes, power is supplied to each actuator 2 according to the allocation determined in S7. Note that if surplus regenerative power is generated in S8 that exceeds the power demand of each actuator 2, it is charged to the battery 10 and/or capacitor 14 by the charge/discharge converter 11 and/or charge/discharge circuit 141.

Figure 11 shows a schematic example of the judgment process of S4, the power allocation amount determination process of S7, and the power supply process of S8. The vertical axis represents power, and the horizontal axis represents time. The curves represent the power that can be supplied by the power control device 4 at each time. As described above, the power that can be supplied by the power control device 4 is the sum of the charge amount of the battery 10, the charge amount of the capacitor 14, and the regenerative power recovered by each actuator 2, and varies greatly depending on time. The stacked bar graphs shown at times T1 and T2 represent the power demand of each actuator 2 at each time. Note that, for the sake of simplicity of illustration and explanation, only the power demand of the actuators 24, 25, and 26 of the working unit is shown. Therefore, the power that can be supplied in the figure includes only the power that can be supplied to the actuators 24, 25, and 26 of the working unit, and does not include the power that can be supplied to the traveling body actuators 21A, 21B and the rotating body actuator 22.

At time T1, the total power demand of each actuator 2 is equal to or less than the power supplyable by the power control device 4, so S4 is judged as No, and in S8, power is supplied to each actuator 2 according to the power demand shown in the figure. At time T2, the total initial power demand of each actuator 2 is assumed to be that shown by the dotted line. In this case, the total power demand of each actuator 2 is greater than the power supplyable by the power control device 4, so S4 is judged as Yes. In S7, the determination unit 44 determines the power to be supplied to each actuator 2 so that the total power demand of each actuator 2 is equal to or less than the power supplyable by the power control device 4. As a result, in S8, power is supplied to each actuator 2 within the range of the power supplyable by the power control device 4. In this way, when the total power demand of each actuator 2 is greater than the power supplyable by the power control device 4, the power allocation to at least one of the actuators 2 is reduced based on the decision of the determination unit 44, so that an appropriate power allocation can be realized within the range of the power supplyable by the power control device 4.

Figure 12 is a flowchart showing an example of the power supply amount determination process of S7 by the determination unit 44. In S11, it is determined whether the main operation of the electric construction machine 100 identified in S5 is a traveling operation by the lower running body 101. If it is determined as Yes in S11, the process proceeds to S12, and the power allocation to the lower running body 101 that performs the main operation is left as it is, and the power allocation to the upper rotating body 102 or the working unit that requires less power is reduced. If it is determined as No in S11, the process proceeds to S13, and it is determined whether the main operation of the electric construction machine 100 identified in S5 is a rotating operation by the upper rotating body 102. If it is determined as Yes in S13, the process proceeds to S14, and the power allocation to the upper rotating body 102 that performs the main operation is left as it is, and the power allocation to the lower running body 101 or the working unit that requires less power is reduced. If the answer is No in S13, the process proceeds to S15, where power is allocated to each actuator 2 according to the operation of the work unit identified in S5 (e.g., excavation operation, swing and loading operation, trench digging operation, ground leveling operation).

Figure 13 shows an example of power allocation to each actuator 2 according to the operation of the working unit. The stacked bar graph of "demanded power" represents the demanded power of each actuator 2, and the stacked bar graphs of "digging operation" and "90-degree rotation loading operation" represent the power allocated to each actuator 2 according to each operation in S15. As shown in the figure, "demanded power" exceeds the power that can be supplied by the power control device 4, but in the "digging operation" and "90-degree rotation loading operation", appropriate power allocation for each operation is realized within the range of the power that can be supplied by the power control device 4. In the "digging operation", more power is allocated to the actuators 24, 25, and 26 of the working unit that are responsible for the excavation operation, while the power required for the traveling body actuators 21A, 21B and the revolving body actuator 22, which require less power, is suppressed or reduced. In the "90-degree rotation loading operation", not only the working unit but also the upper revolving body 102 requires a large amount of power, so the revolving body actuator 22 is allocated power according to the demanded power. On the other hand, in the "90 degree turn loading operation", since the lower traveling body 101 is stopped, the distribution or supply of power to the traveling body actuators 21A, 21B requiring less power is stopped.

In S16, it is determined whether the moment of inertia around the rotation axis of the working unit obtained in S6 is equal to or greater than a predetermined value. If the determination in S16 is Yes, the process proceeds to S17, where the power allocation to the upper rotating body 102 is increased from S15. This is because as the moment of inertia of the working unit increases, the power consumption of the upper rotating body 102 that rotates it increases. The additional power allocated to the upper rotating body 102 is generated by reducing the power allocation to the lower traveling body 101 or the working unit, which require less power. In S18, the amount of power allocated to each actuator 2 is determined through the above processes S11 to S17. As explained in Figures 11 and 13, the total amount of power allocated to each actuator 2 is equal to or less than the power that can be supplied by the power control device 4.

The processing from S19 onwards relates to the allocation of regenerative power recovered by each actuator 2. In S19, the working unit regenerative power (detectable in S2) recovered by the actuators 24, 25, 26 of the working unit is preferentially allocated to the working unit actuator group. In S20, it is determined whether the sum of the working unit regenerative power detected in S2 is greater than the sum of the power allocated to the actuators 24, 25, 26 of the working unit determined in S18. If the answer in S20 is Yes, the process proceeds to S21, where the excess working unit regenerative power is returned to the upper rotating body 102 side or the battery 10/capacitor 14 side via the DC/AC converter 121.

In S22, the running body regenerative power (detectable in S2) recovered by the running body actuators 21A, 21B of the lower running body 101 is preferentially allocated to the running body actuator group. In S23, it is determined whether the total running body regenerative power detected in S2 is greater than the total power allocated to the running body actuators 21A, 21B of the lower running body 101 determined in S18. If the determination in S23 is Yes, the process proceeds to S24, and the excess running body regenerative power is returned to the upper rotating body 102 side or the battery 10/capacitor 14 side via the DC/AC converter 131.

According to the above embodiment, when the total power demand of the multiple actuators 2 is greater than the power supplyable by the power source, the power allocation to at least one of the actuators 2 is reduced based on the decision of the decision unit 44, so that an appropriate power allocation can be achieved within the range of the power supplyable. In particular, when the power source is constituted by a battery 10, the continuous operating time of the power control device 4 and therefore the electric construction machine 100 can be extended by efficiently utilizing the limited charge amount.

The present invention has been described above based on an embodiment. The embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention.

In the configuration example of the power control device 4 in Figure 8, the AC power supplied to each actuator 2 is transmitted non-contact via non-contact transmission units 122, 123, 124, 132, and 133, but the power control device 4 of the present invention can also be applied to electric construction machinery in which DC power generated by the battery 10 is supplied to each actuator 2 via wiring.

In the embodiment, an example of an EMA in which the actuator 2 directly drives each joint component of the electric construction machine 100 has been described, but each joint component of the electric construction machine 100 may be indirectly driven by the actuator 2. For example, if each joint component is directly driven by hydraulic equipment such as a hydraulic motor or hydraulic cylinder, the actuator 2 may be configured as an EHA by using the motor 230 to control a hydraulic valve that controls the hydraulic pressure to each hydraulic equipment.

In the embodiment, the construction machine or electric construction machine is exemplified as having a lower traveling body 101, an upper rotating body 102, a boom 104, an arm 105, and a bucket 106 as joint components, but the present invention can be applied to any construction machine having other joint components. Examples include bulldozers, scrapers, excavators, shovels, transport machines, dump trucks, trailers, shovel loaders, fork loaders, belt conveyors, cranes, construction lifts, forklifts, pile drivers, drilling machines, boring machines, rock drills, road rollers, truck mixers, compressors, pumps, winches, etc.

The functional configuration of each device described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware and software resources. Processors, ROM, RAM, and other LSIs can be used as hardware resources. Programs such as operating systems and applications can be used as software resources.

Among the embodiments disclosed in this specification, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions aggregated, and conversely, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions aggregated. Regardless of whether the functions are aggregated or distributed, it is sufficient that the configuration is such that the object of the invention can be achieved.

The present invention relates to power control technology in construction machinery.

1 Drive unit, 2 Actuator, 4 Power control device, 10 Battery, 11 Charge/discharge converter, 12 Working unit power supply mechanism, 13 Traveling unit power supply mechanism, 14 Capacitor, 15 DC/AC converter, 16 AC/DC converter, 21 Traveling unit actuator, 22 Swinging unit actuator, 24 Boom actuator, 25 Arm actuator, 26 Bucket actuator, 31 DC voltage bus, 32 AC voltage bus, 33 AC voltage bus, 34 DC/AC voltage bus, 40 Operation unit, 41 Demand power acquisition unit, 42 Available power acquisition unit, 43 Power comparison unit, 44 Determination unit, 45 Identification unit, 46 Moment of inertia acquisition unit, 100 Electric construction machine, 101 Lower traveling unit, 102 Upper rotating unit, 104 Boom, 105 Arm, 106 Bucket, 121 DC/AC converter, 122 Boom transmission unit, 123 arm transmission unit, 124 bucket transmission unit, 125 DC removal filter, 126 AC/AC converter, 131 DC/AC converter, 132 step-down transmission unit, 133 step-up transmission unit, 134 DC removal filter, 135 AC/AC converter, 141 charge/discharge circuit, 230 motor, 461 weight acquisition unit, 462 distance acquisition unit.

Claims (11)

A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The operation of the construction machine is a traveling operation,
The determination unit is a power control device that makes the power supplied to a drive unit that drives the lower traveling body greater than the power supplied to a drive unit that drives the upper rotating body, the boom, the arm, and the bucket . The drive information is at least one of an operation command received by an operation unit of the construction machine and an operation command for each of the plurality of drive units,
The identification unit identifies the operation performed by the construction machine based on the correspondence relationship between the operation and the drive information stored in the storage unit and the acquired drive information.
The power control device according to claim 1 . A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The movement of the construction machine is a turning movement,
The determination unit is a power control device that makes the power supplied to a drive unit that drives the upper rotating body greater than the power supplied to drive units that drive the lower traveling body, the boom, the arm, and the bucket. A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The operation of the construction machine is at least one of an excavation operation, a swing loading operation, a trench digging operation, and a ground leveling operation using the boom, the arm, and the bucket,
The determination unit is a power control device that makes the power supplied to a drive unit that drives the boom, the arm, and the bucket greater than the power supplied to a drive unit that drives the lower traveling structure. A weight acquisition unit that acquires information indicating a weight of an object to be transported by the bucket,
the determination unit sets the power supplied to a drive unit having a large load corresponding to the weight of the transported object acquired by the weight acquisition unit, among the drive units of the upper rotating body, the boom, the arm, and the bucket, to be greater than the power supplied to a drive unit having a small load.
The power control device according to claim 4 . A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
A distance acquisition unit that acquires a distance of the bucket from a rotation axis of the upper rotating body,
The power control device wherein the determination unit determines to increase the power to be supplied to the drive unit of the upper rotating body as the distance acquired by the distance acquisition unit increases. A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The decision unit is a power control device that allocates regenerative power recovered by each of the drive units of the boom, the arm, and the bucket among the drive units and decides to return surplus regenerative power that exceeds the total power demand of each of the drive units to the power source. Each of the driving units includes a motor that generates rotational power,
The drive information includes at least one of a rotation speed of each of the motors and a current command value of the motor.
The power control device according to any one of claims 1 to 7 . A power control device for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition unit that acquires drive information of the plurality of drive units;
an identification unit that identifies actions performed by the construction machine through the plurality of joint components based on the drive information;
A determination unit that determines electric power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
a power demand acquisition unit that acquires a power demand for each of the plurality of driving units;
a supplyable power acquisition unit that acquires at least one of a charging rate and a dischargeable amount of the battery as a supplyable power,
The determination unit is a power control device that determines the power to be supplied to the multiple drive units in accordance with the operation of the identified construction machines when the sum of the demanded power exceeds the supplyable power. A power control method for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition step of acquiring drive information of the plurality of drive units;
an identification step of identifying actions performed by the construction machine by the plurality of joint components based on the drive information;
A determination step of determining power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
Equipped with
the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The operation of the construction machine is a traveling operation,
The power control method includes making the power supplied to the drive unit that drives the lower traveling body greater than the power supplied to the drive units that drive the upper rotating body, the boom, the arm, and the bucket in the determining step . A power control program for a construction machine including a plurality of joint components and a power source that supplies power to a plurality of drive units that drive the plurality of joint components,
a drive information acquisition step of acquiring drive information of the plurality of drive units;
an identification step of identifying actions performed by the construction machine by the plurality of joint components based on the drive information;
A determination step of determining power to be supplied to the plurality of driving units in accordance with the identified operation of the construction machine;
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the joint component is at least one of a lower traveling body capable of traveling on the ground, an upper rotating body rotatably attached to the lower traveling body, a boom attached to the upper rotating body so as to be able to be raised and lowered, an arm bendably attached to the boom, and a bucket bendably attached to the arm,
The operation of the construction machine is a traveling operation,
The determination step is a power control program that makes the power supplied to the drive unit that drives the lower traveling body greater than the power supplied to the drive units that drive the upper rotating body, the boom, the arm, and the bucket .

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