JP2016202594A - Motor control device for washing machine - Google Patents

Abstract

In a motor control device for a washing machine, an inverter circuit can be efficiently configured without being limited to components for high voltage and high current, and a motor control device for a washing machine with low cost and good performance is realized.
Control means 6 is a speed control for generating a current command value from a motor rotational speed calculated from an output signal of a rotor position detecting means 4a so that the rotational speed of a brushless motor 4 becomes a desired command rotational speed. Then, the motor current of the brushless motor 4 is divided into a current component corresponding to the magnetic flux and a current component corresponding to the torque, and vector control is performed so as to control each to a desired value. The control means 6 distributes the current command value generated by the speed control in preference to the current command value of the current component corresponding to the magnetic flux when the power supply voltage detection means 7 detects an increase in voltage. By 68, it is made to become below a predetermined maximum current value.
[Selection] Figure 1

Description

  The present invention relates to a motor control device for a washing machine that drives a motor by an inverter circuit.

  In a motor control device that drives a washing and dewatering tub or a pulsator of a washing machine, repeated operations such as stirring are often performed in a short time, and deceleration control that stops the motor in a short time is important. In a motor of a washing machine having a large winding resistance, a so-called short-circuit brake, which is stopped by short-circuiting the motor terminal via the resistor, is not effective, so the frequency is controlled to gradually reduce the rotational speed to obtain a stopped state. At this time, if a sudden stop is performed, a regenerative phenomenon occurs in which the voltage increases due to the back electromotive force of the motor, but the washing machine does not send the generated power to other loads or the power supply side. In the worst case due to voltage boosting by electric power, there is a risk of the inverter circuit being damaged. Therefore, it is necessary to perform rotation control so that an abnormal high voltage state due to regeneration does not occur.

  In view of this problem, a washing machine is disclosed that includes means for controlling the phase angle according to a change in the number of revolutions during deceleration, and suppressing the boosting by consuming the generated regenerative voltage as thermal energy ( For example, Patent Document 1).

JP 2001-46777 A

  In the conventional technology described above, a change in the number of revolutions during deceleration is used to suppress an increase in the regenerative voltage. However, since the regenerative voltage is affected by fluctuations in the power supply voltage, if the regenerative voltage fluctuates, It is difficult to control the voltage below a desired voltage only by detecting a typical change in the rotational speed.

  Therefore, it is conceivable to provide means for detecting the power supply voltage. When the power supply voltage fluctuates, assigning a current value proportional to the amount of voltage fluctuation (deviation) to the current component corresponding to the magnetic flux effectively suppresses regeneration even when the boosted voltage due to regeneration increases because the power supply voltage is high. be able to.

  In order to avoid regeneration in this way, it is sufficient to take a large current component corresponding to the magnetic flux. However, as described above, if the allocation is proportional to the amount of voltage fluctuation, an overcurrent state is caused for a large fluctuation, and the inverter circuit or rotating system There is a risk of placing a heavy burden on the mechanism.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and to provide a motor control device for a washing machine that can reduce a load on an inverter circuit and a circuit system mechanism.

In order to solve the above problems, a motor control device for a washing machine according to the present invention includes a rectifier circuit connected to an AC power source, an inverter circuit that converts DC power rectified by the rectifier circuit into AC power again, and A brushless motor driven by electric power from the inverter circuit, a rotor position detecting means for detecting a rotor position of the brushless motor, a current detecting means for detecting a current of the brushless motor, and a voltage input to the inverter circuit are detected. Power supply voltage detecting means and control means for controlling the inverter circuit, the control means calculating from the output signal of the rotor position detecting means so that the rotation speed of the brushless motor becomes a desired command rotation speed Speed control for generating a current command value from the motor rotation speed, and motor power of the brushless motor. A current control unit for controlling rotation by decomposing the current component corresponding to the magnetic flux and the current component corresponding to the torque, and providing an upper limit to the current value for each current component. When the brushless motor is braked, the control means prioritizes the current command value generated by the speed control over the current command value of the current component corresponding to the magnetic flux when the power supply voltage detection means detects an increase in voltage. However, the current limiting means makes the current value equal to or less than a predetermined maximum current value.

  With the above configuration, the regenerative energy generated during deceleration during brush operation of the brushless motor is consumed as thermal energy in the brushless motor and inverter circuit by preferentially flowing current to the component corresponding to the magnetic flux. Thus, the boost of the voltage input to the inverter circuit due to the regenerative voltage is suppressed, and an upper limit is imposed on the current command value by the current limiting means so that an excessive current is not generated in the inverter circuit.

  Therefore, even if the regenerative voltage fluctuates due to the power supply voltage or other factors, a current command value to be consumed as thermal energy is generated according to the rate of increase, and current limitation is performed. The brushless motor can be decelerated without generating it.

  Further, the current limiting means may be configured not to exceed a predetermined maximum value with respect to a sum of a current command value of a current component corresponding to the magnetic flux and a current command value of a current component corresponding to the torque. With this configuration, it is possible to prevent overcurrent from occurring while braking by applying a current command value of a component corresponding to torque.

  The motor control device for a washing machine of the present invention allows heat energy to be generated in the brushless motor and the inverter circuit by causing the regenerative energy generated at the time of deceleration in the brake operation of the brushless motor to flow preferentially to the component corresponding to the magnetic flux. As a result, it is possible to prevent an excessive current from being generated in the inverter circuit by imposing an upper limit on the current command value by the current limiting means while performing the brake control within a desired voltage range. Accordingly, the inverter circuit can be efficiently configured without being limited to the components for high voltage and high current, and a motor control device for a washing machine with good performance can be provided at low cost.

1 is a block circuit diagram of a motor control device for a washing machine according to Embodiment 1 of the present invention. Motor control flowchart of the motor control device of the washing machine Current limit flowchart of motor control device of the washing machine Flowchart for limiting current of motor control device for washing machine according to embodiment 2 of the present invention

A first invention includes a rectifier circuit connected to an AC power supply, an inverter circuit that converts DC power rectified by the rectifier circuit into AC power again, a brushless motor that is driven by power from the inverter circuit, Rotor position detecting means for detecting the rotor position of the brushless motor, current detecting means for detecting the current of the brushless motor, power supply voltage detecting means for detecting the voltage input to the inverter circuit, and controlling the inverter circuit Control means, and the control means generates a current command value from the motor rotational speed calculated from the output signal of the rotor position detecting means so that the rotational speed of the brushless motor becomes a desired command rotational speed. Control and the motor current of the brushless motor, the current component corresponding to the magnetic flux and the power corresponding to the torque. It implements vector control for controlling rotation by decomposing into components, and further includes current limiting means for giving an upper limit to the current value for each current component, and at the time of braking of the brushless motor, the control means When the power supply voltage detection means detects a voltage increase, the current command value generated by the speed control is distributed with priority over the current command value of the current component corresponding to the magnetic flux, but is predetermined by the current limiting means. This is a motor control device for a washing machine that is set to be equal to or less than a maximum current value.

  As a result, the regenerative energy generated at the time of deceleration in the brake operation of the brushless motor is consumed as thermal energy in the brushless motor and the inverter circuit by flowing current preferentially to the component corresponding to the magnetic flux, and within the desired voltage range. Thus, it is possible to suppress the occurrence of overcurrent mainly to the inverter circuit during braking while performing brake control. In addition, the inverter circuit can be efficiently configured without being limited to components for high voltage and high current, and a motor control device for a washing machine with good performance can be provided at low cost.

  In a second aspect based on the first aspect, the current limiting means is configured to obtain a current component command value corresponding to the magnetic flux and a current component command value corresponding to the torque and a current component command value corresponding to the torque. By assigning the command value as much as necessary to prevent regeneration and limiting the sum so that it does not exceed the predetermined upper limit, the current corresponding to the torque does not exceed the current upper limit value allowed by the circuit. Since components can be assigned, effective braking operation can be continued and the stop time can be shortened while suppressing the generation of excessive current to the inverter circuit due to regeneration.

  According to a third invention, in the first or second invention, the control means changes a setting of a maximum current value based on a driving state of the brushless motor controlled via the inverter circuit, thereby reducing the brushless It is possible to set the margin for overcurrent appropriately for each operation mode by increasing or decreasing the current limit according to the operation mode such as motor start (acceleration), constant speed, braking (deceleration). In addition, it is possible to continue the effective operation of the brushless motor while suppressing the generation of an excessive current to the inverter circuit due to regeneration. In addition, it is possible to provide a function of temporarily lifting the upper limit to enable overload operation and exiting the locked state, such as when restarting due to motor start failure.

  According to a fourth invention, in any one of the first to third inventions, the control means sets a maximum current value based on a driving time and a rotation speed of the brushless motor controlled via the inverter circuit. By changing, it is possible to prevent pressure increase and overcurrent by using a setting with a margin at high rotation, and to set a higher limit value at low rotation to perform quicker braking.

  According to a fifth invention, in any one of the first to fourth inventions, the control means includes a cloth amount detection means for detecting the amount of clothes at the time of washing, and is based on the amount of clothes detected by the cloth amount detection means. By changing the setting of the maximum current value, a setting with a margin can be used to prevent boosting and overcurrent when the load is high and the variation in regenerative voltage and current increases. When the load is low and the load is low, the braking can be performed more quickly by setting a higher limit value.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
As shown in FIG. 1, the AC power source 1 applies an AC voltage to the rectifier circuit 2, and the rectifier circuit 2 converts the AC voltage into a DC voltage by a rectifier 20 and a capacitor 21 and applies the DC voltage to the inverter circuit 3. The inverter circuit 3 is constituted by a three-phase full-bridge inverter circuit composed of six power switching semiconductors and an antiparallel diode, and incorporates an insulated gate bipolar transistor (hereinafter referred to as IGBT), an antiparallel diode, its driving circuit and a protection circuit. The intelligent power module (hereinafter referred to as IPM). The power switching semiconductor may be composed of a metal oxide semiconductor field effect transistor (MOSFET) or the like in addition to the IGBT.

  A brushless motor 4 is connected to the output terminal of the inverter circuit 3. The brushless motor 4 transmits power to a washing and dewatering tub or a pulsator, which is an element constituting the washing machine, via a clutch or the like (not shown), and is driven to rotate. The brushless motor 4 detects the relative position between the permanent magnet constituting the rotor (rotor) and the stator (stator) by the rotor position detecting means 4a. The rotor position detection means 4a is normally composed of three Hall elements and detects a position output reference signal for every electrical angle of 60 degrees. The current detection means 5 detects motor currents Iu, Iv, and Iw of the brushless motor 4, and normally uses a shunt resistor. Further, the motor currents Iu, Iv, and Iw of the brushless motor 4 can be detected by a DC current transformer or an AC current transformer that can be measured from a low frequency including a DC current.

  The control means 6 controls the rotation of the brushless motor 4 by vector control of the inverter circuit 3 by the rotor position detection means 4a and the current detection means 5. The control means 6 comprises a microcomputer and an inverter control timer (PWM timer) built in the microcomputer, a high-speed A / D conversion circuit, a memory circuit (ROM, RAM), etc., and is electrically controlled by an output signal from the rotor position detection means 4a. An electrical angle detection means 60 for detecting the angle, and a three-phase / 2-phase that is decomposed into a current component Id corresponding to the magnetic flux and a current component Iq corresponding to the torque from the output signal of the current detection means 5 and the signal of the electrical angle detection means 60. dq conversion means 61, storage means 62 for storing sine wave data (sin, cos data) necessary for conversion from the stationary coordinate system to the rotation coordinate system or inverse conversion, and voltage component Vd and torque corresponding to the magnetic flux. 2-phase / 3-phase dq reverse conversion means 63 for converting the corresponding voltage component Vq into 3-phase motor drive control voltages Vu, Vv, Vw, and 3-phase motor drive Your voltage Vu, Vv, and a like PWM control means 64 for controlling the IGBT switching of the inverter circuit 3 according to Vw.

  In general, a current component corresponding to the magnetic flux is called a d-axis current Id, and the torque is zero because the permanent magnet magnetic flux and the field magnetic flux are coaxially attracted to the field magnet. Further, the axis where the induced voltage phase is the same as the induced voltage phase at an electrical angle of 90 degrees from the d-axis and the torque is maximum is called the q-axis, and since it is a current component corresponding to the torque, it is called the q-axis current Iq. Furthermore, increasing the d-axis current in the negative direction is equivalent to weakening the field magnetic flux on the d-axis, and is called field weakening control or weakening magnetic flux control (or magnetic flux weakening control). Also, since the motor current is decomposed into d-axis current and q-axis current and controlled independently, it is called vector control.

  The control means 6 includes a setting change means 65 for controlling the activation, maintenance of the number of revolutions, and braking of the brushless motor 4 according to the washing process, and a number of revolutions detecting means 66 for detecting the number of revolutions from the output signal of the rotor position detecting means 4a. The motor current setting means 67 for determining the current setting value Iqs for Iq and the current setting value Ids for Id, and the limiter for Ids and Iqs so that the motor current setting means 67 does not give Ids and Iqs that are not less than a predetermined upper limit value. Current limiting means 68 for generating values Ids' and Iqs' multiplied by Ids and Iqs' generated by the current limiting means 68, Id and Iq calculated by the three-phase / 2-phase dq conversion means 61, And a motor voltage control means 69 for calculating a voltage component Vd corresponding to the magnetic flux for controlling the brushless motor 4 and a voltage component Vq corresponding to the torque. It is equipped with a.

The power supply voltage detection means 7 detects the voltage of the rectifier circuit 2 and outputs the minimum voltage Vmin during acceleration or constant speed rotation of the brushless motor 4 and the current voltage Vp, and is constituted by, for example, two resistors. The voltage doubled from the rectifier circuit 2 is detected as a divided voltage.

  By performing feedback control so that the q-axis current Iq matches the current set value Iqs, motor operation with a constant torque becomes possible. However, since the motor induced voltage increases and the q-axis current Iq does not increase as the rotational speed increases, so-called weakening magnetic flux control is performed to increase the d-axis current Id according to the rotational speed, and the q-axis current Iq is reduced. Increase the torque. In this embodiment, the current set value input to the motor voltage control means 69 is via the current limiting means 68, and thus refers to the limited current set value Iqs ′. The current set value for which 69 is instructed is not particularly described as a limited current set value.

  The electrical angle detector 60 can detect the electrical angle θ every 60 degrees from the output reference signals H1, H2, and H3 obtained from the three Hall elements of the rotor position detector 4a. If it is in any other position, the electrical angle θ is updated by estimation from the electrical angle detected immediately before (within 60 degrees) and the current rotational speed. Specifically, an interrupt is generated at a period synchronized with the PWM carrier wave, and the current rotation speed is calculated by measuring the period at which the electrical angle changes by 60 degrees by the number of carrier interrupts. An electrical angle Δθ per carrier signal period is obtained. The latest electrical angle θ = θold + k · Δθ can be calculated from the immediately preceding electrical angle θold, the carrier interrupt count k generated after obtaining θold, and the electrical angle Δθ per cycle of the carrier signal.

  The three-phase / two-phase dq conversion means 61 converts the three-phase motor currents Iu, Iv, and Iw into two coordinate axis currents (d-axis current Id and q-axis current Iq), and is estimated by the electrical angle detection means 60. Id and Iq are calculated from the electrical angle θ and the instantaneous motor current value detected by the current detection means 5. If the current value of the two phases of the three-phase current is known from Kirchhoff's law, the remaining one-phase current can be obtained, so in this embodiment, only Iu and Iv are used. A current value may be used.

  Since the storage unit 62 stores the data of sin θ and cos θ, it can be decomposed into the d-axis current Id and the q-axis current Iq by calling the data corresponding to the electrical angle data and performing the product-sum operation. In the present embodiment, the calculation is performed by software using the sine wave data preset in the storage means 62 and the dq conversion is performed. It may be calculated and dq converted without preparing data in the storage means.

  The rotation speed detection means 66 detects the motor rotation speed from the output reference signal of the rotor position detection means 4 a and transmits the rotation speed signal to the setting change means 65 and the motor current setting means 67. In this embodiment, the rotation speed is detected using the H3 input as an output reference signal. However, any one of the Hall element signals H1 to H3 may be used as the output reference signal, and the rotation speed is set for each of the three elements. You may ask and average.

  The setting change means 65 sets the target rotational speed Ns of the brushless motor 4 according to the requested washing operation content. The flow of processing when the motor is started will be described with reference to the flowchart of FIG.

  In step 201, since the brushless motor 4 starts from a stopped state, the motor current cannot be detected and vector control cannot be performed. Although not shown in FIG. 1, an initial voltage is given to the PWM control means 64 instead of the 2-phase / 3-phase dq inverse conversion means 63 (step 201).

As a result, the brushless motor 4 is activated (step 202), and when the rotation is more than a predetermined angle, if the activation of the brushless motor 4 can be detected by the electrical angle detection means 60 (step 203), the process proceeds to the next step. Since the rotational speed detection accuracy cannot be obtained, the motor current setting means 67 starts the initial vector control independent of the rotational speed by giving the d-axis current initial value Id0 and the q-axis current initial value Iq0 from the setting changing means 65. (Step 204). If rotation cannot be detected, the modulation degree is gradually increased as time passes (step 205), and the voltage control in step 202 is continued.

  Thereafter, as shown in FIG. 2, the setting change means 65 gives the initial current setting values Iq0 and Id0 to the motor current setting means 67 (step 204), and acquires the rotation speed from the rotation speed detection means 66 ( Step 206) and the initial vector control / feedback switching are sent to the control switching unit 67d (step 207), the initial vector control is shifted to the normal vector control, and the desired rotation speed is performed while performing feedback until the rotation stops thereafter. Is obtained (step 208).

  The motor current setting means 67 compares the set rotational speed Ns of the brushless motor 4 instructed by the setting changing means 65 with the current rotational speed N obtained from the rotational speed detecting means 66 to obtain a rotational speed error ΔN. PI control is performed in accordance with the number comparison means 67a, the rotation speed error ΔN and the change rate (acceleration) of the rotation speed, and the q-axis current set value Iqs is controlled so that the current rotation speed N approaches the set rotation speed Ns q Iqs and Ids are respectively generated by the shaft current setting unit 67b and the d-axis current setting unit 67c that similarly controls the d-axis current set value Ids.

  This will be described below with reference to the flowchart shown in FIG.

  The power supply voltage detection means 7 acquires the voltage (hereinafter referred to as P voltage Vp) input to the inverter circuit 3 in accordance with the PWM carrier interrupt cycle (step 302). The current P voltage Vp and the minimum value of the P voltage during acceleration and constant speed (hereinafter referred to as P voltage command value Vmin) are sent to the d-axis current setting means 67c for motor control. When braking (when Yes in step 303), the d-axis current setting unit 67c increases the P voltage command value Vmin to suppress an increase in the P voltage Vp when the P voltage Vp increases due to a regenerative phenomenon (step 304). A deviation ΔVp from the P voltage Vp is obtained (step 305), and a d-axis current value Ids proportional to ΔVp is set (step 306).

  As a result, when the voltage increases due to fluctuations in the power supply voltage and regeneration increases, more current is distributed in the d-axis direction according to the rate of increase, and the current in the q-axis direction is further reduced to further increase the current. By preventing the regeneration and consuming the generated regenerative energy as the thermal energy of the d-axis current by the brushless motor 4 and the inverter circuit 3, an increase in the P voltage Vp can be suppressed.

  During acceleration or constant speed (No in step 303), the P voltage command value Vmin and Vp are compared (step 310), and if Vp is small, Vmin is updated (step 311). If no increase in the P voltage Vp is observed during acceleration, constant speed, or deceleration, setting Ids = 0 allows the motor current to be used to the maximum in the q-axis direction, that is, for torque control. Thus, effective acceleration / deceleration control can be performed (step 312).

  The d-axis current limiting means 68a included in the current limiting means 68 compares the d-axis current set value Ids set by the d-axis current setting means 67c with a d-axis current limit value Idmax prepared in advance in the storage means 62 ( Step 307) When Ids exceeds Idmax, the d-axis current set value Ids is limited to Idmax (Step 308).

The motor voltage control means 69 compares the output signals Iq and Id of the three-phase / two-phase dq conversion means 61 with the set values Iqs and Ids, and outputs control voltage signals Vq and Vd. It comprises means 69a, q-axis voltage setting means 69b, d-axis current comparison means 69c, and d-axis voltage setting means 69d, and generates voltage signals Vq and Vd for controlling the q-axis current and the d-axis current, respectively.

  The two-phase / three-phase dq inverse conversion means 63 calculates the three-phase motor drive control voltages Vu, Vv, Vw from the voltage signals Vq, Vd, and the electric angle detected by the electric angle detection means 60 in synchronization with the carrier signal. A sinusoidal signal corresponding to the angle θ is output to the PWM control means 64. The method of product-sum calculation of sin θ and cos θ stored in the storage means 62 is almost the same as the calculation of the three-phase / 2-phase dq conversion means 61.

  As described above, in the first embodiment of the present invention, the regenerative energy generated during deceleration is determined by determining the d-axis current command value (d-axis current set value) according to the rate of increase in the P voltage during deceleration. Is consumed as thermal energy in the brushless motor and the inverter circuit, and boosting due to the regenerative voltage can be suppressed. At the same time, by limiting the d-axis current command value, it is possible to suppress the overcurrent and protect the inverter circuit.

(Embodiment 2)
In the motor control device for a washing machine according to Embodiment 2 of the present invention, the d-axis current set value Ids and the q-axis current set value Iqs are allocated to the current in the d-axis direction as much as necessary for preventing regeneration, and d By setting the q-axis current so that the sum of the axis current set value Ids and the q-axis current set value Iqs does not exceed the predetermined current upper limit value, the d-axis current is within a range not exceeding the current upper limit allowed by the circuit. Can be used for regenerative energy consumption, and q-axis current can be used for rotation control (brake). This method will be described with reference to the flowcharts of FIGS.

  In FIG. 3, as in the first embodiment, the d-axis current limiting means 68a outputs a d-axis current set value Ids ′ that is limited so as not to exceed a predetermined d-axis current limit value Idmax (step 308). ).

  When the q-axis current limit unit 68b receives the d-axis current set value Ids ′ and the q-axis current set value Iqs set by the q-axis current set unit 67b, the sum exceeds the current limit value Imax allowed by the device. In the case (step 401), the q-axis current set value Iqs is reset so as to be equal to or less than Imax (step 402).

Here, since the sum of the d-axis current setting value Ids ′ and the q-axis current setting value Iqs ′ (the q-axis current setting value Iqs to which the restriction is applied) is represented by vector synthesis,
(Iqs ′) 2+ (Ids ′) 2 ≦ (Imax) 2
Q-axis current set value Iqs ′ is set so that When Ids = 0, Iqs = Imax, and the maximum current allowed by the device can be used for torque control.

  Imax may be the same as the maximum current value Idmax allowed by the inverter circuit 3 described above, or may be determined separately from Idmax in consideration of the torque direction, that is, the load applied to the drive component.

  As described above, in the second embodiment of the present invention, the effect of the first embodiment, that is, the allocation of d-axis current, the inverter circuit from the overcurrent due to the suppression of the boost due to consumption of regenerative energy and the limitation of the d-axis current If the d-axis current alone does not exceed the maximum current value allowed for the entire circuit, the remaining is assigned as the q-axis current, and effective braking can be performed while suppressing the occurrence of overcurrent. .

(Embodiment 3)
In the motor control device for a washing machine according to the third embodiment of the present invention, the setting change means 65 is determined in advance based on the driving state of the brushless motor 4, for example, a state such as starting, constant speed, or decelerating. The shaft current limit value Idmax and the current limit value Imax allowed by the device are changed.

  With this configuration, for example, at the time of restart due to motor start failure, the upper limit can be temporarily raised to enable overload operation, and a function of exiting the locked state can be provided.

(Embodiment 4)
In the motor control device for a washing machine according to the fourth embodiment of the present invention, the setting changing unit 65 determines the d-axis current limit value Idmax and the current limit allowed by the device according to the drive time of the brushless motor 4 and the desired rotation speed. Change the value Imax.

  Since the state of regeneration and overcurrent varies depending on the load on the brushless motor 4, for example, in the case of stirring where the influence of the load is greater, this configuration ensures a large margin for overcurrent generation. It becomes possible to set the upper limit value lower.

(Embodiment 5)
In the motor control device for a washing machine according to Embodiment 5 of the present invention, the control means 6 is provided with a cloth amount detection means (not shown in FIG. 1) for detecting the amount of clothes during washing, and is detected by the cloth amount detection means. The setting changing means 65 changes the d-axis current limit value Idmax and the current limit value Imax allowed by the device according to the drive time of the brushless motor 4 and the desired number of rotations according to the amount of load (clothing). As the cloth amount detection means, for example, a weight sensor, a light sensor, or a total amount or an average of the amount of current required when a stirring operation is performed at the start of operation can be applied.

  If the amount of cloth is large, the variation of the cloth state increases and the influence of resistance fluctuation due to the load increases. However, according to the configuration of the present embodiment, the setting change means 65 generates overcurrent when the amount of cloth is large. It is possible to set the above-mentioned limit value low so as to ensure a large margin for the above.

  The motor control device for a washing machine according to the present invention can suppress boosting due to the regenerative voltage by determining the d-axis current command value according to the rate of increase of the P voltage during deceleration, and at the same time, d By setting a limit on the shaft current command value, it is possible to protect the inverter circuit by suppressing overcurrent, so washing that takes a very long time to stop with a short-circuit brake with a motor with high winding resistance etc. It can utilize suitably for motor control apparatuses, such as a machine.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier circuit 3 Inverter circuit 4 Brushless motor 4a Rotor position detection means 5 Current detection means 6 Control means 7 Power supply voltage detection means 60 Electrical angle detection means 61 Three-phase / two-phase dq conversion means 62 Storage means 63 Two-phase / Three-phase dq reverse conversion means 64 PWM control means 65 Setting change means 66 Rotational speed detection means 67 Motor current setting means 68 Current limiting means 69 Motor voltage control means

Claims (5)

A rectifier circuit connected to an AC power source; an inverter circuit that converts DC power rectified by the rectifier circuit into AC power again; a brushless motor that is driven by power from the inverter circuit; and a rotor position of the brushless motor. Rotor position detection means for detecting; current detection means for detecting the current of the brushless motor; power supply voltage detection means for detecting a voltage input to the inverter circuit; and control means for controlling the inverter circuit; The control means includes a speed control for generating a current command value from a motor rotation speed calculated from an output signal of the rotor position detection means so that a rotation speed of the brushless motor becomes a desired command rotation speed, and the brushless motor. The motor current is decomposed into a current component corresponding to the magnetic flux and a current component corresponding to the torque. And vector control for controlling rotation by giving, and current limiting means for giving an upper limit to the current value for each current component, and at the time of braking of the brushless motor, the control means detects the power supply voltage When the means detects an increase in voltage, the current command value generated by the speed control is distributed with priority over the current command value of the current component corresponding to the magnetic flux, and the current limiting means determines the maximum current The motor control device of the washing machine that makes it below the value. 2. The current limiting unit is configured so that a sum of a current command value of a current component corresponding to the magnetic flux and a current command value of a current component corresponding to the torque is equal to or less than a predetermined maximum current value. Washing machine motor control device. The motor control device for a washing machine according to claim 1 or 2, wherein the control means changes a setting of a maximum current value based on a driving state of the brushless motor controlled via the inverter circuit. The motor control of the washing machine according to any one of claims 1 to 3, wherein the control means changes a setting of a maximum current value based on a driving time and a rotation speed of the brushless motor controlled via the inverter circuit. apparatus. The said control means is provided with the cloth amount detection means which detects the clothing amount at the time of washing, and the setting of the maximum electric current value is changed based on the clothing amount detected by the said cloth amount detection means. The motor control device of the washing machine as described.

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