JP6682926B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device.

  The motor control device is required to continue the motor control even when there is an abnormality. Therefore, the motor control device is configured to have redundancy. For example, in Patent Document 1, two 3-phase windings form a total of 6-phase stator windings, a drive circuit is provided for each 3-phase winding, and usually 6-phase driving is performed. When the winding has a short-circuit break, driving of the three-phase winding having the break is stopped, and the remaining normal three-phase winding is driven.

  Further, Patent Document 2 proposes a motor drive system for a five-phase motor. In Patent Document 2, normally, when a 5-phase motor is driven by a 5-phase inverter and one or more phases become abnormal, the power supply of the phase having the abnormality is stopped and the remaining normal phase Of these, three or more phases are driven.

  Further, in Patent Document 3, when an abnormality occurs in one of the phase arms of a three-phase inverter that drives a three-phase motor, the drive of the abnormal phase arm is stopped and the motor winding of the three-phase electric motor is wound. The current path to and is cut off, and the phase arm that has stopped driving is replaced by the redundant arm section.

JP, 2006-203957, A JP, 2013-141335, A JP, 2005-2634, A, 0054

  In Patent Document 1, since a drive circuit and a power supply are provided for each three-phase winding to form two systems, there is an advantage that the motor can be driven even when there is an abnormality in one power supply. However, the drive circuit (inverter) If a part of the motor fails, the motor will have half the output because it is driven from 6-phase to 3-phase.

  In Patent Document 2, a drive circuit (inverter) is configured. For example, if there is an abnormality in the switching element of one phase arm, the motor can output more than half of the normal output because it can be driven by the other phase arm, but it drives the 5-phase inverter. No countermeasure is disclosed when there is an abnormality in the drive circuit.

Patent Document 3 does not disclose a case in which there is an abnormality in the gate drive circuit that drives the three-phase inverter that controls the phase arm and the redundant arm unit.
It is an object of the present invention to provide a motor control device that produces a constant torque regardless of the phase so that torque fluctuation does not occur .

In order to solve the above problems, a motor control device of the present invention is a motor control device that drives a multi-phase motor having six or more phases by a plurality of drive systems, each drive system being a motor of the multi-phase motor. An inverter that supplies AC power to a coil, a motor control device that includes a control unit that includes a gate drive circuit that drives the inverter and that controls the inverter of the drive system, and a power supply unit that supplies power to the inverter, The inverter has a phase arm that supplies AC power to at least three-phase motor coils of each phase, and the control unit controls a phase of an inverter of a part of the drive systems among the inverters of the plurality of drive systems. If the switching elements constituting the arms of the short-circuit failure, remaining so as to cancel the torque generated by the motor coils corresponding to the phase arms of the short-circuiting failure With using a normal phase arms in inverter drive system of the other, but intends line to continue the motor control by using other normal phase arm in inverters of the remaining other drive system.

According to the present invention, it is possible to prevent a torque fluctuation by generating a constant torque regardless of the phase .

(A) is a circuit diagram of the motor control device of the first embodiment, (b) is a waveform diagram of the motor current of each phase in the normal state of the first embodiment. The abnormality determination flowchart which a control part performs. The circuit diagram of the motor control device when the gate drive circuit of one drive system fails. (A) is a circuit diagram of a motor control device showing a time when an upper switching element has an open failure in a phase arm of an inverter in one drive system, and (b) is a waveform diagram of a phase current of each phase at that time. FIG. 6 is a waveform diagram of a phase current of each phase when the upper switching element is short-circuited in the phase arm of the inverter in one drive system. (A) is a circuit diagram of a motor control device showing a case where a lower switching element has failed in a phase arm of an inverter in one drive system, and (b) is a waveform of a phase current of each phase when the lower switching element has an open failure. Fig. FIG. 6 is a waveform diagram of a phase current of each phase when a lower switching element has a short circuit failure in a phase arm of an inverter in one drive system. (A) is a circuit diagram of the motor control device in the second embodiment, and (b) is a circuit diagram of the motor control device when one drive system or the control circuit fails. The circuit diagram of the motor control device of a 3rd embodiment. The circuit diagram of the motor control device of a 4th embodiment.

(First embodiment)
A first embodiment embodying a motor control device of the present invention will be described below with reference to FIGS. Although the use of the motor control device is not limited, for example, the motor control device is used as an electric power steering device that is installed in a vehicle and assists a steering operation, or a rear wheel drive device that generates a driving force on rear wheels. .

  As shown in FIG. 1A, the motor control device includes a motor 10, an inverter unit 20 that supplies AC power to the motor 10, a gate drive circuit unit 30, a control unit 40, and batteries Ba and Bb as power sources. Is equipped with.

  The batteries Ba and Bb are high-voltage (for example, 100 V or more) or low-voltage (for example, 12 V) direct-current power supplies, which are rechargeable nickel-hydrogen or lithium-ion secondary batteries, for example. The batteries Ba and Bb correspond to a power supply unit.

  In the present embodiment, the motor 10 is a 6-phase brushless motor, and has star-connected a to f phase motor coils La to Lf, and the gate drive circuit unit 30 and the inverter unit 20 are in a normal state. In this case, the number of magnetic poles of the motor is set so that the phase currents flowing through the motor coils La to Lf have a phase difference of 60 degrees. The motor coils La to Lf correspond to windings.

The inverter unit 20 includes an inverter 20A that drives the motor coils La to Lc and an inverter 20B that drives the motor coils Ld to Lf.
The inverter 20A includes phase arms a to c. The phase arm a is composed of a series circuit of switching elements 21a and 21b, the phase arm b is composed of a series circuit of switching elements 22a and 22b, and the phase arm c is composed of a series circuit of switching elements 23a and 23b. ing.

  The inverter 20B includes phase arms d to f. The phase arm d is composed of a series circuit of switching elements 24a and 24b, the phase arm e is composed of a series circuit of switching elements 25a and 25b, and the phase arm f is composed of a series circuit of switching elements 26a and 26b. ing.

  In the present embodiment, the switching element is an N-channel type MOS (Metal Oxide Semiconductor) FET, but it may be a P-channel type. Although not shown, each N-channel MOSFET has a built-in PN junction diode. The anode of this built-in diode is electrically connected to the source of the corresponding switching element, and the cathode is electrically connected to the drain of the corresponding switching element. ing.

  The phase arms a to c of the inverter 20A are provided in parallel between the power supply line L1 connected to the battery Ba and the ground (earth) line L2. A relay switch Ra is provided between the battery Ba and the phase arm a in the power supply line L1. The connection point a1 of the switching elements 21a and 21b, the connection point b1 of the switching elements 22a and 22b, and the connection point c1 of the switching elements 23a and 23b are connected to one ends of the motor coils La, Lb, and Lc, respectively.

  The phase arms d to f of the inverter 20B are provided in parallel between the power supply line L3 connected to the battery Bb and the ground (earth) line L4. In the power supply line L3, a relay switch Rb is provided between the battery Bb and the phase arm d. The connection point d1 of the switching elements 24a and 24b, the connection point e1 of the switching elements 25a and 25b, and the connection point f1 of the switching elements 26a and 26b are connected to one ends of the motor coils Ld, Le, and Lf, respectively.

  Connection point a1 and motor coil La, connection point b1 and motor coil Lb, connection point c1 and motor coil Lc, connection point d1 and motor coil Ld, connection point e1 and motor coil Le, and connection point f1. Current sensors Sa to Sf are provided between the motor coils Lf. The current sensors Sa to Sf output the detected phase current to the control unit 40.

The gate drive circuit unit 30 includes a gate drive circuit 30A that drives the inverter 20A and a gate drive circuit 30B that drives the inverter 20B.
The control unit 40 is composed of a microcomputer, and controls the inverters 20A and 20B by outputting control command signals to the gate drive circuits 30A and 30B based on various parameters.

  For example, in the motor control device of the electric power steering device, the control unit 40 inputs the steering torque signal from the torque sensor and the steering angle signal from the steering angle sensor provided on the column shaft (not shown) as parameters. Then, the control unit 40 calculates the target phase current so as to assist the steering by the steering according to the vehicle speed, and based on the calculated target phase current, the control command signal matched with the rotational position signal is supplied to the gate drive circuit 30A. , 30B to control the inverters 20A, 20B.

  Specifically, the control unit 40 switches ON / OFF of the switching elements 21a, 21b, 22a, 22b, 23a, 23b, 24a, 24b, 25a, 25b, 26a, 26b via the gate drive circuits 30A, 30B. Thus, the inverters 20A and 20B are controlled. That is, since the gates of the respective switching elements are connected to the output terminals of the gate drive circuits 30A and 30B, the gate drive circuits 30A and 30B change the gate voltage to switch ON / OFF of the switching elements.

Further, the control unit 40 performs feedback control so that there is no deviation between the target phase current and the phase current of the motor 10 input from the current sensors Sa to Sf.
As described above, the motor control device according to the present embodiment includes the drive system including the gate drive circuit 30A, the inverter 20A, and the motor coils La to Lc, and the drive system including the gate drive circuit 30B, the inverter 20B, and the motor coils Ld to Lf. Two drive systems are provided, and both drive systems are controlled by a single control unit 40.

(Operation of the embodiment)
Next, the operation of this embodiment will be described.
FIG. 2 is a flowchart relating to a drive system abnormality determination program executed by the control unit 40 in each predetermined control cycle.

(S10)
In S10, the control unit 40 performs the following determination process.
<State judgment of gate drive circuit>
Although not shown, the gate drive circuits 30A and 30B are provided with a gate drive circuit state detection unit that detects a voltage on the output side from the gate drive circuits 30A and 30B and outputs the detection signal to the control unit 40. There is.

  When the control unit 40 outputs a control command signal to the gate drive circuits 30A and 30B to drive the phase arms of each phase, whether the gate drive circuits 30A and 30B are normally operating according to the control command signal. Whether or not the state is judged is performed based on the detection signal from the gate drive circuit state detector. For example, the control unit 40 outputs a control command signal for driving the switching element of the phase arm of the inverter to the gate drive circuit, but the gate voltage (detection) applied from the gate drive circuit to the switching element of the phase arm is detected. Signal) does not satisfy the normal condition, it is judged as an abnormal state. For example, the normal condition includes that the gate voltage for turning on or off the switching element is not output based on the control command signal.

  Further, the control unit 40 determines that the gate voltage from the corresponding gate drive circuit with respect to the switching element of the phase arm satisfies the normal condition as a normal state. The abnormality determination is not limited to the above determination.

The determination here is called state determination of the gate drive circuit.
<Determination of state of gate drive circuit section>
The result of the state determination of the gate drive circuit section here is one of the following.

<1> The gate drive circuit unit 30 (gate drive circuits 30A and 30B) is normal <2-1> The gate drive circuit 30A is normal and the gate drive circuit 30B is abnormal <2-2> The gate drive circuit 30A is abnormal and gate drive Circuit 30B is normal <3> Both gate drive circuits 30A and 30B are abnormal <Inverter state determination>
Further, the control unit 40 continues the phase current to a constant value (constant) based on the phase current (the detection signal input from the current sensors Sa to Sf) regarding the inverter of the drive system belonging to the gate drive circuit in the normal state. Whether or not the switching element of each phase arm has an open failure or a short circuit failure is determined depending on whether or not the value is described later). When the switching element of the phase arm has either an open failure or a short failure, the control unit 40 determines that it is abnormal, and when neither of the failures is normal, it determines that it is normal.

  In addition, in the case of <2-1>, <2-2>, and <3>, the control unit 40 controls the phase arm switching element for the inverter of the drive system to which the gate drive circuit determined to be in the abnormal state belongs. Whether or not there is an open failure or a short failure is not determined.

Here, the determination of the open failure and the short failure will be described.
(Failure judgment of upper switching element)
In the case where the upper switching element has an open failure, the phase current does not continue to flow in the motor coil connected to the upper switching element even when the gate voltage for turning on the upper switching element is applied. 0 which is a constant value is detected. Therefore, based on the detection signal of the current sensor that detects the phase current of the phase arm, if the control unit 40 continues to have a constant value of 0, the upper switching element of the phase arm has an open failure. It is determined that

  In addition, when the upper switching element has a short-circuit fault, the phase current (peak current) of the motor coil connected to the upper switching element is also short because it is short-circuited even when the upper switching element has an off gate voltage. The value (> 0) continues to flow.

  Therefore, if the peak value continues as a constant value based on the detection signal from the current sensor that detects the phase current of the phase arm, the control unit 40 causes the upper switching element of the phase arm to have a short circuit failure. It is determined that

(Fault determination of lower switching element)
If the lower switching element has an open failure, the phase current will not flow in the motor coil connected to the lower switching element even if a gate voltage for turning on the lower switching element is applied. A constant value of 0 is continuously detected. Therefore, based on the detection signal of the current sensor detecting the phase current of the phase arm, if the control unit 40 continues to have a constant value of 0, the lower switching element of the phase arm has an open failure. It is determined that

  When the lower switching element has a short circuit failure, the phase current (bottom value <0) is constant from the motor coil connected to the lower switching element even when the lower switching element has an off gate voltage. As it continues to flow. Therefore, based on the detection signal of the current sensor that detects the phase current of the phase arm, if the bottom value continues as a constant value, the control unit 40 determines that the lower switching element of the phase arm has a short circuit failure. judge.

The state determination of the inverter unit 20 is not limited to the above method, and other methods may be used.
The control unit 40 determines whether all of the phase arms of the inverter are normal, some of them are normal, or all of them are abnormal, based on the individual judgment results obtained as described above.

The result of the state determination of the inverter unit 20 here is one of the following.
<4> Inverter unit 20 (inverters 20A, 20B) is normal <5-1> All phase arms of inverter 20A are normal and all phase arms of inverter 20B are abnormal <5-2> All phases of inverter 20A The arm is normal, and part of the phase arm of the inverter 20B (that is, one phase arm) is abnormal. <5-3> All phase arms of the inverter 20A are normal and part of the inverter 20B (that is, two phase arms). <6-1> All phase arms of the inverter 20A are abnormal and all phase arms of the inverter 20B are normal <6-2> Part of the inverter 20A (that is, one phase arm) Is abnormal, and all the phase arms of the inverter 20B are normal. <6-3> Some of the phase arms of the inverter 20A (that is, two phase arms) are Normally, all phase arms of the inverter 20B are normal. <7-1> All phase arms of the inverters 20A and 20B are abnormal. <7-2> Each of the inverters 20A and 20B has one or two abnormal phase arms. However, the number n of abnormal phase arms of both inverters is 1 ≦ n ≦ 4.
<8-1> In the case of <2-1> above, all the phase arms of the inverter 20A are normal. <8-2> In the case of <2-2> above, all the phase arms of the inverter 20B are normal (S20).
When the above <1> and <4>, the control section 40 performs normal 6-phase motor control in S20. When the control unit 40 controls the gate drive circuits 30A and 30B in the normal state and the inverters 20A and 20B in the normal state, the phase currents flowing through the motor coils La to Lf are currents having a phase difference of 60 degrees. (See FIG. 1 (b)).

(S30)
The control unit 40, when <8-1>, <8-2>, <1>, and <5-1>, or <1>, <6-1. If>, the following processing is performed in S30.

  The control unit 40 opens the relay switch of the drive system that is determined to have the failure. For example, when the gate drive circuit 30A fails, the relay switch Ra is opened as shown in FIG. In this case, the power supply from the battery Ba to the gate drive circuit 30A and the inverter 20A is cut off.

  Further, the control unit 40 performs normal motor control for the drive system to which the gate drive circuit determined to be normal, that is, drives the three-phase motor coils of the normal drive system. The driving of this three-phase motor coil is performed by the same method as the driving method of the six-phase motor coil, assuming that both drive systems are normal.

  As a result, although the output of the motor 10 decreases, the motor control can be continued. When the motor control device is an electric power steering device, when it is normal, smooth assist can be executed by the multi-phase motor, and even if the gate drive circuit of one drive system fails, power is supplied to the failed drive system. It can be stopped and eliminated, and motor control can be continued with the remaining normal drive system.

(S40)
When <1> and <5-2>, or <1> and <6-2>, the control unit 40 performs the following process in S40.

The control unit 40 uses the normal phase arm for the gate drive circuits 30A and 30B to perform 5-phase or 4-phase cooperative control.
(Five-phase coordinated control)
When the upper switching element forming the phase arm has an open failure, the control unit 40 performs cooperative control of five phases. In the present embodiment, the control unit 40 controls the phase current in each phase with respect to the switching elements of the normal 5-phase phase arm so that a constant torque is obtained regardless of the phase. In this method, torque fluctuation is prevented regardless of the phase, but the present invention is not limited to this method.

  The example of FIG. 4A shows a case where the switching element 26a, which is the upper switching element of the phase arm f of the inverter 20B, has failed, and the other phase arms are normal. In this case, when the control unit 40 controls the phase current in each phase so that a constant torque is obtained for the switching element of the normal 5-phase phase arm regardless of the phase as described above, the motor coil Lf , The phase currents of the other motor coils La to Le are as shown in FIG. 4B.

  Further, as shown in FIG. 6A, when the lower switching element forming the phase arm has an open failure, the control unit 40 performs the 5-phase cooperative control. In the present embodiment, the control unit 40 controls the phase current in each phase with respect to the switching elements of the normal 5-phase phase arm so that a constant torque is obtained regardless of the phase. In this method, torque fluctuation is prevented regardless of the phase, but the present invention is not limited to this method.

  The example of FIG. 6A shows a case where the switching element 26b, which is the lower switching element of the phase arm f of the inverter 20B, has failed and the other phase arms are normal. In this case, when the control unit 40 controls the phase current in each phase so that a constant torque is obtained for the switching element of the normal 5-phase phase arm regardless of the phase as described above, the motor coil Lf , The phase currents of the other motor coils La to Le are as shown in FIG. 6B.

(Four-phase coordinated control)
When the switching element forming the phase arm has a short circuit failure, the control unit 40 controls the phase having the short circuit failure and the phase having a difference of 180 deg so as to have the same potential. As a result, the torque generated by the phase of the short circuit failure is canceled by the torque generated by the phase of 180 deg difference. Further, the control unit 40 drives the remaining normal phase arms in four phases.

  In FIG. 4A, when the switching element 26a, which is the upper switching element of the phase arm f of the inverter 20B, has a short circuit failure and the other phase arms are normal, the phase current of the motor coil Lf is short circuited. Since it is out of order, the peak value of the phase current of the motor coil Lf flows constantly.

  In such a case, the control unit 40 causes the switching element so that the same phase current as the phase current of the motor coil Lf flows through the motor coil La having a phase difference of 180 degrees from the motor coil Lf, that is, the same potential. 24a is controlled. Then, for the other normal switching elements of the four-phase arm, the phase current in each phase is controlled so that a constant torque is generated regardless of the phase so that torque fluctuation does not occur. (See Figure 5). Note that, in FIG. 5, the phase current of the motor coil La is the same as the phase current of the motor coil Lf, and therefore, for convenience of description, the phase current is shown by a bold single-dot chain line indicating the phase current of the motor coil Lf.

  Further, in FIG. 6A, when the switching element 26b, which is the lower switching element of the phase arm f of the inverter 20B, has a short circuit failure and the other phase arms are normal, the phase current of the motor coil Lf is Since there is a short circuit failure, the phase current of the motor coil Lf has a bottom value and flows constantly.

  In such a case, the control unit 40 causes the switching element so that the same phase current as the phase current of the motor coil Lf flows through the motor coil La having a phase difference of 180 degrees from the motor coil Lf, that is, the same potential. 24a is controlled. Then, for the other normal switching elements of the four-phase arm, the phase current in each phase is controlled so that a constant torque is generated regardless of the phase so that torque fluctuation does not occur. (See Figure 7). Note that, in FIG. 7, the phase current of the motor coil La is the same as the phase current of the motor coil Lf, and therefore, for convenience of description, the phase current is shown by a bold single-dot chain line indicating the phase current of the motor coil Lf.

The 5-phase cooperative control and the 4-phase cooperative control as described above can be controlled by a preset program.
(S50)
Further, in the determination process of S10, the control unit 40, when <3>, is <1>, and when <7-1>, is <1>, and <7-2>, <5. If -3> or <6-3>, the entire drive system is abnormal, or it is determined that sufficient motor drive cannot be performed even if the motor is controlled by controlling the entire drive system, and the process proceeds to S50. In S50, the control unit 40 opens the relay switches Ra and Rb, and stops the motor control by each drive system by the control unit 40.

The present embodiment has the following features.
(1) In the motor control device of the present embodiment, the control unit 40, when the phase arms of the inverters 20A, 20B of one of the drive systems among the inverters 20A, 20B of the plurality of drive systems are abnormal, the phase of the abnormality is detected. The driving of the arms a to f is stopped. Then, the control unit 40 continues the motor control for the gate drive circuits 30A and 30B of the one drive system by using the remaining normal phase arms a to f. Further, when the gate drive circuit of one drive system among the gate drive circuits 30A and 30B of the plurality of drive systems is abnormal, the gate drive circuit of the abnormal state is stopped and the remaining drive systems are operated normally. Continue motor control using the gate drive circuit.

  As a result, according to the present embodiment, when some of the phase arms of the inverter are abnormal, the drive output can be continuously controlled without halving the output of the motor, and the gate drive circuit of one system is abnormal. In this case, the motor can be continuously driven and controlled.

  (2) In this embodiment, when the gate drive circuits 30A and 30B of one drive system are abnormal, the control unit 40 continues the control of the second motor by the normal gate drive circuits 30A and 30B. The relay switches Ra and Rb provided between the power supply unit and the inverters 20A and 20B of the drive system to which the abnormal gate drive circuits 30A and 30B belong are controlled to be cut off.

As a result, according to the present embodiment, it is possible to cut off the power supply to the inverter of the drive system belonging to the abnormal gate drive circuit.
(3) In the motor control device of the present embodiment, the batteries Ba and Bb are provided for each of the inverters 20A and 20B, and the inverters 20A and 20B and the power supply of the drive system to which the inverters 20A and 20B belong are relay switches Ra. , Rb are provided. As a result, according to the present embodiment, in each drive system, the power supply to the inverter of the drive system belonging to the abnormal gate drive circuit can be cut off.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 8 (a) and 8 (b). In each of the following embodiments including the present embodiment, the same components as those in the first embodiment will be designated by the same reference numerals, detailed description thereof will be omitted, and different components will be described.

  In the first embodiment, the control unit 40 controls both the gate drive circuits 30A and 30B, but in the present embodiment, the control circuits 40A and 40B are different for each drive system. Further, the control circuits 40A and 40B include gate drive circuits 30A and 30B, respectively. The control circuits 40A and 40B correspond to the control unit 40.

  Further, the detection signals of the current sensors Sa to Sf are input to the control circuits 40A and 40B, and the control circuits 40A and 40B respectively perform the determination processing performed by the control unit 40 in the first embodiment. . In addition, the control circuits 40A and 40B are configured to perform mutual communication and determine whether or not the results of the respective determination processes match. Then, when the determination results match, and when the control unit 40 of the first embodiment opens the relay switches Ra and Rb with respect to the drive system and there is a failure determination in one drive system, other The control circuit of the drive system opens the relay switches Ra and Rb of the drive system for which the failure determination has been made. Further, when the determination results match, when performing the 5-phase cooperative control or the 4-phase cooperative control, each control circuit 40A, 40B causes the 5-phase cooperative control or the 4-phase cooperative control based on a preset program. Coordinated control of phases is performed.

  Further, in the present embodiment, the control command signals output from the control circuits 40A and 40B to the gate drive circuits 30A and 30B are monitored by the control circuits of other drive systems. Then, the control circuit of the other drive system determines whether the control command signal is within a predetermined threshold range. In this case, the control command signal is determined to be a normal value if it is within the predetermined threshold range, and is an abnormal value if it is out of the range.

  When the control command signal has an abnormal value, the control circuit on the side determined to be abnormal opens the relay switches Ra and Rb of the other drive system. FIG. 8B shows a state where the control circuit 40B opens the relay switch Ra when the control command signal of the control circuit 40A is abnormal.

  In the present embodiment, by being configured as described above, when each of the control circuits 40A and 40B has an abnormality in a part of the phase arm of the inverter of the drive system to which it belongs, the control circuit 40A, 40B is normal to the drive system to which it belongs. The remaining phase arms are used to continue the first motor control.

  Further, when the gate drive circuits 30A and 30B of the drive system other than the drive system to which the self belongs are abnormal, the second motor control is continued using the normal gate drive circuit of the drive system to which the self belongs.

The motor control device according to the present embodiment, which is configured as described above, has the following effects.
(1) In the motor control device of the present embodiment, when some of the phase arms a to f of the inverters 20A and 20B of the drive system to which the control circuit 40A and 40B belong are abnormal, the drive system to which the motor control device belongs is normal. The remaining phase arms can be used to continue the first motor control.

  When the control circuit 40A, 40B causes an abnormality in a gate drive circuit of a drive system other than the drive system to which the control circuit 40A or 40B belongs, a normal gate drive circuit of the drive system to which the control circuit 40A or 40B belongs is used to control the second motor. You can continue.

  (2) In the motor control device of the present embodiment, each control circuit 40A, 40B uses the normal gate drive circuit of the drive system to which the control circuit of the other drive system belongs if the control circuit of the other drive system is abnormal. The motor control can be continued.

(Third Embodiment)
Next, the motor control device of the third embodiment will be described with reference to FIG. The present embodiment differs from the first embodiment in that the battery Bb is omitted in the configuration of the first embodiment and the power supply unit is configured by the battery Ba. According to the present embodiment, since the battery Ba is the power supply unit of both drive systems, the number of batteries can be reduced and the cost can be reduced as compared to the first and second embodiments.

(Fourth Embodiment)
Next, a motor control device of the fourth embodiment will be described with reference to FIG.
The motor 10 of the present embodiment is a 9-phase brushless motor, and differs from the first embodiment in that it has star-connected a to i-phase motor coils La to Li.

  Further, the motor control device includes a drive system including a gate drive circuit 30A, an inverter 20A, and motor coils La to Lc, a gate drive circuit 30B, an inverter 20B, a drive system including motor coils Ld to Lf, and a gate drive circuit 30C. It is provided with three systems, an inverter 20C and a drive system including motor coils Lg to Li. Then, the motor control device controls each drive system by the single control unit 40. The motor coils La to Li correspond to windings.

  The inverter 20C includes phase arms g to i. The phase arm g is composed of a series circuit of switching elements 27a and 27b, the phase arm h is composed of a series circuit of switching elements 28a and 28b, and the phase arm i is composed of a series circuit of switching elements 29a and 29b. ing.

  The phase arms g to i of the inverter 20C are provided in parallel between the power supply line L5 connected to the battery Bc and the ground (earth) line L6. In the power supply line L5, a relay switch Rc is provided between the battery Bc and the phase arm g.

  The connection point g1 of the switching elements 27a and 27b, the connection point h1 of the switching elements 28a and 28b, and the connection point i1 of the switching elements 29a and 29b are connected to one ends of the motor coils Lg, Lh, and Li, respectively. Current sensors Sg to Si are provided between the connection point g1 and the motor coil Lg, between the connection point h1 and the motor coil Lh, and between the connection point i1 and the motor coil Li. The current sensors Sa to Si output the detected phase current to the control unit 40. The gate drive circuit unit 30 includes a gate drive circuit 30A that drives the inverter 20A, a gate drive circuit 30B that drives the inverter 20B, and a gate drive circuit 30C that drives the inverter 20C.

  The controller 40 is composed of a microcomputer, and controls the inverters 20A, 20B, 20C by outputting control command signals to the gate drive circuits 30A, 30B, 30C based on various parameters. The power supply unit of this embodiment is composed of batteries Ba, Bb, and Bc.

  In the present embodiment, of the inverters 20A, 20B, and 20C belonging to each drive system, if the phase arm of the inverter of a part of the drive system is abnormal, the drive of the abnormal phase arm is stopped and the part of the relevant phase arm is stopped. The first motor control is continued for the gate drive circuit section of the drive system using the remaining normal phase arm. Since the motor of the present embodiment is a 9-phase brushless motor, even if the 3-phase arm is abnormal, the control unit 40 drives the remaining 6-phase arm by cooperative control.

  In addition, in the present embodiment, the control unit 40 stops the abnormal gate drive circuit when any one of the three drive systems has an abnormal gate drive circuit, and the remaining normal gate drive circuits are stopped. The drive circuit is used to continue the second motor control.

  That is, when any one of the gate drive circuits 30A to 30C is abnormal, the control unit 40 continues to control the second motor by the remaining normal gate drive circuits of the two drive systems, and the batteries Ba, Bb, The relay switches Rb, Rb, and Rc provided between Bc and the inverter of the drive system to which the abnormal gate drive circuit belongs are controlled to be cut off.

As described above, even if the gate drive circuit of one drive system becomes abnormal, the torque drops, but the motor can be continuously controlled by the other two drive systems.
In the case where the motor control device of the present embodiment is an electric power steering device, smooth assistance can be provided by the multi-phase motor, and assistance can be continued even in the event of a failure, and motor output drop can be suppressed in response to the failure location. it can.

It should be noted that the embodiment of the present invention is not limited to the above embodiment, and may be modified as follows.
The six-phase brushless motor is used in the first and second embodiments and the nine-phase brushless motor is used in the fourth embodiment, but the number of phases of the motor may be six or more. In particular, when continuing the first motor control, it is preferable that the number of normal phase arms is a number at which the output of the motor is half or more.

The motor is not limited to the brushless motor, but may be another type of motor such as an induction motor.
The switching element is not limited to the MOSFET, but may be a power MOS (Metal Oxide Semiconductor) transistor, an IGBT (Insulated Gate Bipolar Transistor), a power bipolar transistor, or the like.

The power supply unit is not limited to the battery, but may be composed of an AC power supply and a converter that converts the power of the AC power supply into DC.
-In 1st Embodiment, when the upper switching element which comprises a phase arm has an open failure, the control part 40 performs 5 phase cooperative control. In this embodiment, the control unit 40 generates the constant torque regardless of the phase so that the torque fluctuation does not occur. However, if there is no problem even if the motor torque fluctuation occurs, the torque fluctuation may occur. May occur.

-In 4th Embodiment, although the power supply part was comprised with three batteries Ba, Bb, Bc, you may comprise with one or two batteries.
-In 3rd Embodiment and 4th Embodiment, you may provide a control circuit for every drive system.

In the fourth embodiment, the 9-phase brushless motor is used, but it may be embodied in a motor control device for a multi-phase brushless motor.
In the above-described embodiment, the inverter of each drive system is configured to drive the motor coils of three phases, but the motor coil driven by one inverter is not limited to a unit of three phases, but a motor coil of two phases. A motor coil or four or more phases may be used as a unit.

10 ... Motor, 20 ... Inverter part,
20A, 20B ... Inverter,
21a, 21b, 22a, 22b, 23a, 23b ... Switching elements,
24a, 24b, 25a, 25b, 26a, 26b ... Switching elements,
27a, 27b, 28a, 28b, 29a, 29b ... Switching element,
30 ... Gate drive circuit unit, 30A, 30B ... Gate drive circuit,
40 ... Control unit, 40A, 40B ... Control circuit,
a to f ... Phase arm, a1 to f1 ... Connection point,
Ba, Bb ... Battery (power source, power source section),
L1, L3, L5 ... Power line, L2, L4, L6 ... Ground line,
La to Li ... Motor coil (winding),
Ra, Rb ... Relay switch.

Claims (3)

A motor control device for driving a multi-phase motor of 6 phases or more by a plurality of drive systems, each drive system supplying AC power to a motor coil of the multi-phase motor, and a gate drive circuit for driving the inverter. In a motor control device including a control unit that controls the inverter of the drive system, and a power supply unit that supplies power to the inverter,
The inverter has a phase arm that supplies AC power to motor coils of at least three phases or more,
The control unit is
When a switching element forming a phase arm of some drive system inverters among the plurality of drive system inverters has a short circuit failure, the torque generated in the motor coil corresponding to the short circuit failure phase arm is offset. the remaining other with using a normal phase arms in inverter drive system, the line cormorants motor controller to continue the motor control by using other normal phase arm in inverters of the remaining other drive system to. The polyphase motor is a 6-phase motor,
  The control unit is
  When a switching element forming a phase arm of some drive system inverters among the plurality of drive system inverters has a short circuit failure, a phase current flowing through a motor coil corresponding to the short circuit phase arm and the short circuit The normal phase arm in the other inverter of the other drive system is used so that the motor coil corresponding to the failed phase arm and the phase current flowing in the motor coil having a phase difference of 180 deg become the same, and the remaining normal phase arm is used. The motor control device according to claim 1, wherein the motor control is continued by using another normal phase arm in the inverter of another drive system. When a gate drive circuit of a part of the drive systems among the gate drive circuits of the plurality of drive systems is abnormal, the control unit stops the gate drive circuit of the abnormality, and the other drive system of the other drive systems is stopped. The motor control device according to claim 1, wherein the motor control is continued by using a normal gate drive circuit .

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