JP2019146383A - Motor control device - Google Patents

Abstract

To improve performance of a four-phase SR motor.SOLUTION: The motor control device, which rotationally drives a four-phase SR motor by switching energization to winding corresponding to respective phases of the four-phase SR motor from a power supply part, comprises: a pair of three-phase inverters connected to two-phase winding of an A-phase and a B-phase and two-phase winding of a C-phase and a D-phase respectively; and a control part that controls phase currents flowing into the winding by controlling a plurality of switching elements in each three-phase inverter into an on-state or an off-state. The control part makes the power supply part to regenerate phase currents without refluxing phase currents flowing into a non-energizing phase.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device for a four-phase switched reluctance motor.

  When a switched reluctance motor (hereinafter referred to as “SR motor”) having a frictionless characteristic is multi-phase, the driving circuit of the SR motor is generally phase-independent driving. The cost of parts increases. Therefore, in the case of a four-phase SR motor, a configuration has been devised in which a pair of three-phase inverters having versatility such as driving for a three-phase brushless motor is used (see Patent Document 1).

JP 2002-369580 A

  By the way, in the case of a four-phase SR motor, the characteristic is improved by setting the basic energization angle to 90 ° energization and setting an appropriate energization angle according to each rotation speed and torque. Therefore, when two-phase energization is performed, the phase current of the other phase becomes unstable due to the influence of the magnetic flux of one phase in the energized phase, and as a result, the performance may deteriorate.

  This invention is made | formed in view of such a situation, The objective is to provide the motor control apparatus which can improve the performance of a four-phase SR motor.

  One aspect of the present invention is a motor control device that rotationally drives an SR motor by switching energization from a power supply unit to a winding corresponding to each phase of a four-phase SR motor, and includes an A phase and a B phase. A pair of three-phase inverters connected to each of the two-phase windings of C phase and D-phase, and a plurality of switching elements in each of the three-phase inverters in an on state or an off state A control unit that controls the phase current flowing in the winding by controlling, and the control unit regenerates the power source unit without recirculating the phase current flowing in the non-conduction phase. This is a motor control device.

  One aspect of the present invention is the above-described motor control device, in which the control unit performs PWM control of energization of at least one of the two phases that is an energized phase, and the PWM control off period The phase current flowing in the other phase which is a non-energized phase is regenerated in the power supply unit.

  One aspect of the present invention is the above-described motor control device, wherein the control unit performs PWM control of the switching element of the lower arm and controls the switching element of the upper arm to the on state among the plurality of switching elements. Thus, the phase current flowing in the energized phase is PWM controlled, and the phase current flowing in the non-energized phase is regenerated in the power supply unit.

  One aspect of the present invention is the above-described motor control device, wherein the switching element of the lower arm that performs PWM control is a switching element of the lower arm that is connected to a connection point of the two-phase winding.

  As described above, according to the present invention, the performance of a four-phase SR motor can be improved.

It is a figure which shows an example of schematic structure of the motor system 1 provided with the motor control apparatus 2 which concerns on one Embodiment of this invention. It is a figure which shows an example of schematic structure of SR motor M which is the control object of the motor control apparatus 2 which concerns on one Embodiment of this invention. It is a figure explaining the electricity supply pattern with respect to the switching element of the three-phase inverter 4-1 which concerns on this embodiment. It is a figure explaining energization pattern # 1 concerning one embodiment of the present invention. It is a figure explaining energization pattern # 2 concerning one embodiment of the present invention. It is a figure explaining energization pattern # 3 concerning one embodiment of the present invention. It is a figure explaining energization pattern # 4 concerning one embodiment of the present invention. It is a figure explaining the electricity supply pattern with respect to the switching element of the three-phase inverter 4-1 and 4-2 which concerns on one Embodiment of this invention.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention. In the drawings, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted. In addition, the shape and size of elements in the drawings may be exaggerated for a clearer description.

  Hereinafter, a motor control device 2 according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a schematic configuration of a motor system 1 including a motor control device 2 according to an embodiment of the present invention. As shown in FIG. 1, the motor system 1 includes a motor control device 2, an SR motor M, and a rotation angle sensor K. The motor control device 2 rotationally drives a four-phase switched reluctance motor (SR motor) M. The SR motor M is used, for example, as a motor that drives a vehicle wheel.

FIG. 2 is a diagram illustrating an example of a schematic configuration of the SR motor M that is a control target of the motor control device 2 according to the embodiment of the present invention.
As shown in FIG. 2, the SR motor M includes a rotor R and a stator S.

The rotor R includes six salient pole portions RP1 to RP6 arranged at equal intervals on the circumference.
The stator S is provided so as to surround the rotor R. Further, the stator S has eight salient pole portions SP1 to SP8 toward the inner rotor R.

  Windings are wound around the eight salient pole portions SP1 to SP8. Specifically, an A-phase winding (hereinafter referred to as “A-phase winding”) La is wound around the salient pole part SP1 and the salient pole part SP5. A B-phase winding (hereinafter referred to as “B-phase winding”) Lb is wound around the salient pole part SP3 and the salient pole part SP7. A C-phase winding (hereinafter referred to as “C-phase winding”) Lc is wound around the salient pole part SP2 and the salient pole part SP6. A D-phase winding (hereinafter referred to as “D-phase winding”) Ld is wound around the salient pole part SP4 and the salient pole part SP8.

The motor control device 2 selectively energizes the A-phase winding La, the B-phase winding Lb, the C-phase winding Lc, and the D-phase winding Ld, whereby salient pole portions SP1 to SP8 of the stator S. Magnetically attracts the salient pole portions RP1 to RP6 of the rotor R to generate a driving torque and a braking torque in the rotor R. Thereby, the SR motor M is rotationally driven.
Returning to FIG. 1, a specific configuration of the motor control device 2 will be described below.

  The motor control device 2 includes a power supply unit 3, a pair of three-phase inverters 4-1 and 4-2, a current sensor 5, and a control unit 6.

  The power supply unit 3 is, for example, a battery mounted on the vehicle. The power supply unit 3 can use a secondary battery such as a nickel metal hydride battery or a lithium ion battery. Moreover, an electric double layer capacitor (capacitor) can be used instead of the secondary battery.

  The pair of three-phase inverters 4-1 and 4-2 are connected to the A-phase winding La and the B-phase winding Lb, and the C-phase winding Lc and the D-phase winding Ld, respectively.

The three-phase inverter 4-1 includes six switching elements AH, AL, N _AB H, N _AB L, BH, and BL connected in a three-phase bridge. In the present embodiment, the case where the switching elements AH, AL, N _AB H, N _AB L, BH, and BL are n-type channel FETs (Field Effective Transistors) will be described. However, the present invention is not limited to this. (Insulated gate bipolar transistor) and BJT (bipolar junction transistor) may be used.

  The switching elements AH and AL are connected in series to each other and constitute one switching leg. The switching element AH is an upper arm switching element (hereinafter referred to as “upper arm switching element”). On the other hand, the switching element AL is a lower arm switching element (hereinafter referred to as “lower arm switching element”).

  Switching element AH has a drain connected to the positive electrode of power supply unit 3 and a source connected to the drain of switching element AL. The source of the switching element AL is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements AH and AL is connected to the control unit 6. Further, a neutral point that is a connection point between the source of the switching element AH and the drain of the switching element AL is connected to one end of the A-phase winding La.

  The switching elements BH and BL are connected in series to each other and constitute one switching leg. The switching element BH is an upper arm switching element. On the other hand, the switching element BL is a lower arm switching element.

  The switching element BH has a drain connected to the positive electrode of the power supply unit 3 and a source connected to the drain of the switching element BL. The source of the switching element BL is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements BH and BL is connected to the control unit 6. A neutral point that is a connection point between the source of the switching element BH and the drain of the switching element BL is connected to one end of the B-phase winding Lb.

The switching elements N _AB H and N _AB L are connected in series to each other and constitute one switching leg. The switching element N _AB H is an upper arm switching element. On the other hand, the switching element N _AB L is a lower arm switching element.

The switching element N _AB H has a drain connected to the positive electrode of the power supply unit 3 and a source connected to the drain of the switching element N _AB L. The source of the switching element N _AB L is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements N _AB H and N _AB L is connected to the control unit 6. The neutral point that is the connection point between the source of the switching element N _AB H and the drain of the switching element N _AB L is the connection point between the other end of the A-phase winding La and the other end of the B-phase winding Lb. It is connected.

The three-phase inverter 4-2 includes six switching elements CH, CL, N _CD H, N _CD L, DH, and DL connected in a three-phase bridge. In the present embodiment, the case where the switching elements CH, CL, N _CD H, N _CD L, DH, and DL are n-type channel FETs will be described. However, the present invention is not limited to this, and is, for example, IGBT or BJT. May be.

  The switching elements CH and CL are connected in series to each other and constitute one switching leg. The switching element CH is an upper arm switching element. On the other hand, the switching element CL is a lower arm switching element.

  The switching element CH has a drain connected to the positive electrode of the power supply unit 3 and a source connected to the drain of the switching element CL. The source of the switching element CL is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements CH and CL is connected to the control unit 6. Further, a neutral point that is a connection point between the source of the switching element CH and the drain of the switching element CL is connected to one end of the C-phase winding Lc.

  The switching elements DH and DL are connected in series with each other and constitute one switching leg. The switching element DH is an upper arm switching element. On the other hand, the switching element DL is a lower arm switching element.

  The switching element DH has a drain connected to the positive electrode of the power supply unit 3 and a source connected to the drain of the switching element DL. The source of the switching element DL is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements DH and DL is connected to the control unit 6. Further, a neutral point that is a connection point between the source of the switching element DH and the drain of the switching element DL is connected to one end of the D-phase winding Ld.

The switching elements N _CD H and N _CD L are connected in series to each other and constitute one switching leg. The switching element N _CD H is an upper arm switching element. On the other hand, the switching element N _CD L is a lower arm switching element.

The switching element N _CD H has a drain connected to the positive electrode of the power supply unit 3 and a source connected to the drain of the switching element N _CD L. The source of the switching element N _CD L is connected to the negative electrode of the power supply unit 3. Each gate of the switching elements N _CD H and N _CD L is connected to the control unit 6. The neutral point that is the connection point between the source of the switching element N _CD H and the drain of the switching element N _CD L is the connection point between the other end of the C-phase winding Lc and the other end of the D-phase winding Ld. It is connected.

  The current sensor 5 includes currents (hereinafter referred to as “phase currents”) flowing through the A phase winding La, B phase winding Lb, C phase winding Lc, and D phase winding Ld of the SR motor M, respectively. Detect and output to the control unit 6.

The control unit 6 includes switching elements AH, AL, N _AB H, N _AB L, BH, BL of the three-phase inverter 4-1, and switching elements CH, CL, N _CD H, N _{CD of the} three-phase inverter 4-2. Control signals are transmitted to the gates of the switching elements L, DH, and DL. Thereby, each switching element of the three-phase inverters 4-1 and 4-2 is switched between an on state and an off state. Thereby, the current from the power supply unit 3 is energized to each of the A-phase winding La and B-phase winding Lb, and the C-phase winding Lc and D-phase winding Ld. That is, the control unit 6 rotationally drives the SR motor M by switching energization of the windings corresponding to each phase of the SR motor M.
Below, the structure of the control part 6 which concerns on one Embodiment of this invention is demonstrated.

  The control unit 6 includes a current command value generation unit 7, a current detection unit 8, a position detection unit 9, a rotation speed detection unit 10, an advance / energization angle setting unit 11, an energization timing output unit 12, a current control unit 13, and a drive. A control unit 14 is provided.

  The current command value generation unit 7, for example, responds to an accelerator signal indicating the operation amount (depression force amount) of the accelerator pedal of the vehicle, and the A phase winding La, B phase winding Lb, and C phase winding Lc of the SR motor M. , A target value (hereinafter referred to as “current command value”) of a current flowing through each of the D-phase windings Ld is acquired. Then, the current command value generation unit 7 outputs the acquired current command value to the advance / energization angle setting unit 11 and the current control unit 13. For example, the current command value generation unit 7 includes a table in which an accelerator pedal operation amount and a current command value are associated with each other, and acquires a current command value corresponding to the accelerator pedal operation amount indicated by the accelerator signal from the table. Thus, the current command value is calculated. Further, the current command value generation unit 7 may experimentally determine the current command value from the operation amount of the accelerator pedal indicated by the accelerator signal.

  The current detector 8 detects the phase current value flowing through each of the A phase winding La, B phase winding Lb, C phase winding Lc, and D phase winding Ld of the SR motor M output from the current sensor 5. To do. Then, the current detection unit 8 outputs the detected phase current value of each phase to the current control unit 13. For example, the current detection unit 8 detects the phase current that is energized in the SR motor M based on the detection signal of each phase current output from each current sensor 5, and outputs this phase current value to the current control unit 13. To do.

  The position detection unit 9 detects the rotation angle of the rotor R (rotation position of the rotor R) based on the signal output from the rotation angle sensor K, and uses the detection result as the rotation speed detection unit 10 and the energization timing output unit 12. Output to.

  The rotation speed detection unit 10 detects the amount of change per unit time of the signal indicating the rotation angle of the rotor R output from the position detection unit 9, and calculates the rotation speed (number of rotations) of the rotor R from the detected change amount. . Then, the rotation speed detection unit 10 outputs the calculated rotation speed to the advance / energization angle setting unit 11.

  The advance angle / energization angle setting unit 11 outputs an advance angle and an energization angle according to the current command value output from the current command value generation unit 7 and the rotation speed output from the rotation speed detection unit 10. To the unit 12. For example, the advance / energization angle setting unit 11 includes an advance angle map unit 11a and an energization angle map unit 11b.

  The advance angle map unit 11a determines the advance angle based on the current command value output from the current command value generation unit 7 and the rotation speed output from the rotation speed detection unit 10. Then, the advance angle map unit 11 a outputs the determined advance angle to the energization timing output unit 12. For example, the advance angle map unit 11a is a map in which the advance value is associated with each combination of the current command value and the rotation speed of the rotor R. Here, the advance angle refers to the energization start phase and the energization end phase for each winding of each phase of the SR motor M at predetermined positions (for example, an inductance increase start phase and a decrease start phase) according to the inductance change of each phase. Represents the angle at which the energization angle is changed to the advance side. Note that the advance angle tends to increase with increasing current command value and rotation speed. For example, the advance angle map unit 11a is set from a simulation, a measurement result by an actual machine, or the like.

  The energization angle map unit 11b determines the energization angle based on the current command value output by the current command value generation unit 7 and the rotation speed output by the rotation speed detection unit 10. Then, the energization angle map unit 11 b outputs the determined energization angle to the energization timing output unit 12. For example, the conduction angle map unit 11b is a map in which the value of the conduction angle is associated with each combination of the current command value and the rotation speed of the rotor R. Here, the energization angle is associated with each of the A-phase winding La, the B-phase winding Lb, the C-phase winding Lc, and the D-phase winding Ld of the SR motor M. The conduction angle map unit 11b is set from a simulation or a measurement result by an actual machine.

  The energization timing output unit 12 acquires the rotational position of the rotor R output from the position detection unit 9 and the advance angle and energization angle output from the advance / energization angle setting unit 11. Then, the energization timing output unit 12 generates the A-phase winding La, the B-phase winding Lb, the C-phase winding Lc, and the D-phase winding based on the acquired rotational position of the rotor R, the advance angle, and the energization angle. The energization timing for energizing Ld is determined. And the energization timing output part 12 outputs the timing signal which shows the energization timing to the determined winding of each phase to a PWM output part.

  The current control unit 13 calculates a deviation between the current command value supplied from the current command value generation unit 7 and the phase current value supplied from the current detection unit 8 (hereinafter referred to as “current difference value”). The current control unit 13 outputs the calculated current difference value to the drive control unit 14.

The drive control unit 14 calculates the duty ratio based on the difference between the current values using generally known PI (Proportional Integral) control or PID (Proportional Integral Derivative) control.
Then, the drive control unit 14 generates a control signal based on the calculated duty ratio and the timing signal output from the energization timing output unit 12. Then, the drive control unit 14 transmits the generated control signal to the gates of the switching elements of the three-phase inverter 4-1 and the three-phase inverter 4-2 according to a plurality of preset energization patterns.

  The energization pattern is a switching pattern for turning on or off the switching elements in the three-phase inverters 4-1 and 4-2, and is continuously turned on (“ON”) or continuously turned off. Either "OFF" state (period other than "ON" or "PWM (Pulse Width Modulation)") or a state controlled to be turned on or off at a constant cycle (PWM controlled state) ("PWM") It is a combination.

  Therefore, in other words, the drive control unit 14 controls the ON state and the OFF state of the switching elements in the three-phase inverters 4-1 and 4-2, so that the A-phase winding La and the B-phase winding Lb The energization pattern for energizing the C-phase winding Lc and the D-phase winding Ld is switched.

  Accordingly, the drive control unit 14 controls each of the plurality of switching elements in each of the three-phase inverters 4-1 and 4-2 to be in an on state or an off state with a plurality of energization patterns, thereby winding each phase winding (A The phase current flowing in the phase winding La, the B phase winding Lb, the C phase winding Lc, and the D phase winding Ld) is controlled.

Here, one of the features of the present embodiment is that when the A phase and the B phase are alternately excited by sequentially switching the energization pattern, the phase is flowing in the non-energized phase that is not the energized phase (energized phase). The current is regenerated in the power supply unit 3 without refluxing the current. For example, when the B phase is an energized phase, the drive control unit 14 causes the power source unit 3 to regenerate a phase current (residual current) flowing in the A phase that is a non-energized phase.
Similarly, the drive control unit 14 recirculates the phase current flowing in the non-energized phase that is not the energized phase (energized phase) when the C phase and the D phase are alternately excited by sequentially switching the energization pattern. The power supply unit 3 is regenerated without any trouble. For example, when the D phase is the energized phase, the drive control unit 14 causes the power source unit 3 to regenerate the phase current (residual current) flowing in the C phase that is the non-energized phase.

  Below, the energization pattern with respect to the switching element of the three-phase inverter 4-1 is demonstrated using FIGS. FIG. 3 is a diagram for explaining energization patterns for the switching elements of the three-phase inverter 4-1 according to the present embodiment. FIG. 4 is a diagram illustrating the energization pattern # 1 according to the present embodiment. FIG. 5 is a diagram illustrating the energization pattern # 2 according to the present embodiment. FIG. 6 is a diagram illustrating the energization pattern # 3 according to the present embodiment. FIG. 7 is a diagram illustrating the energization pattern # 4 according to the present embodiment.

  As shown in FIG. 3, the drive control unit 14 according to this embodiment includes four energization patterns (energization patterns) that alternately excite the A-phase winding La and the B-phase winding Lb in the three-phase inverter 4-1. The drive control unit 14 repeatedly switches the energization patterns in the order of the energization patterns # 1, # 2, # 3, and # 4 in the three-phase inverter 4-1.

(Energization pattern # 1)
In the energization pattern # 1, the drive control unit 14 controls the switching element BH (upper arm switching element) to be in an ON state, and performs PWM control of the switching element N _AB L (lower arm switching element). Thus, the phase current I _B flows as an excitation current in the negative direction with respect to the B phase winding Lb. That is, in energization pattern # 1, the energized phase is the B phase and the non-energized phase is the A phase. The negative direction is a direction in which a phase current flows from one end side of the A-phase winding La or B-phase winding Lb to the other end side (neutral point side). On the other hand, the positive direction is a direction in which a phase current flows from the other end side (neutral point side) of the A phase winding La or the B phase winding Lb to one end side.

Therefore, as shown in FIG. 4, when both the switching element BH and the switching element N _AB L are in the on state, the switching element BH, the B-phase winding Lb, and the switching element N _AB L are sequentially supplied from the power supply unit 3. A current flows and the B-phase winding Lb is excited (FIG. 4 (a): supply mode).

When the switching element N _AB L is in the OFF state during PWM control, the phase current I _B flowing through the B-phase winding Lb passes through the switching element N _AB H and the switching element BL and passes through the B-phase winding Lb. Reflux in the negative direction. That is, a closed loop is formed by the B-phase winding Lb, the switching element N _AB H, and the switching element BL (FIG. 4B: reflux mode). Thereby, the excitation of the B-phase winding Lb is continued. On the other hand, the phase current I _A flowing through the A-phase winding La is regenerated to the power supply unit 3 via the freewheeling diode of the switching element N _AB H. That is, the drive control unit 14 forms a circuit including the switching element AL, the A-phase winding La, the freewheeling diode of the switching element N _AB H, and the power supply unit 3 during the PWM control of the switching element N _AB L. , is regenerated to the power supply unit 3 without recirculating phase current I _a flowing through the a-phase winding La in the three-phase inverter within 4-1. Phase current I _A regenerated to the power supply unit 3 remains in the A-phase when switching the current supply phase to the B phase from the A-phase, a so-called residual current.

When the drive control unit 14 switches from the energization pattern # 1 to the energization pattern # 2, both the switching element BH and the switching element N _AB L are turned off. Thus, the phase current I _B generated by the counter electromotive force of the B phase winding Lb is regenerated as power source 3 to the reflux diode of the switching element N _{AB H} (FIG. 4 (c): regeneration mode).

(Energization pattern # 2)
In the energization pattern # 2, the drive control unit 14 controls the switching element AL (lower arm switching element) to be in an ON state, and performs PWM control of the switching element N _AB H (upper arm switching element). Thereby, the phase current I _A flows in the positive direction with respect to the A-phase winding La. That is, in energization pattern # 2, the energized phase is the A phase and the non-energized phase is the B phase.

Therefore, as shown in FIG. 5, when both the switching element AL and the switching element N _AB H are in the ON state, the switching element N _AB H, the A-phase winding La, and the switching element AL are sequentially supplied from the power supply unit 3. Current flows and the A-phase winding La is excited (FIG. 5A: supply mode).

Further, when the switching element N _AB H is under PWM control, when the switching element AL is in the on state and the switching element N _AB H is in the off state, the phase current I _A flowing through the A phase winding La is , Through the return diodes of the switching element AL and switching element N _AB L, and return to the A-phase winding La in the positive direction. That is, a closed loop is formed by the A-phase winding La, the switching element AH, and the return diode of the switching element N _AB L (FIG. 5B: return mode). Thereby, the excitation of the A-phase winding La is continued. On the other hand, the phase current I _B flowing through the B-phase winding Lb is regenerated to the power supply unit 3 via the freewheeling diode of the switching element N _AB H. That is, the drive control unit 14, during the PWM control of the switching element _{N AB} H, the switching element BL, B phase winding Lb, by forming a freewheeling diode of the switching element _{N AB} H, and the circuit composed of the power supply unit 3 , it is regenerated to the power supply unit 3 without the phase current I _B flowing through the B-phase winding Lb refluxed in a three-phase inverter within 4-1. The power supply unit phase current I _B which is regenerated in 3 remains in phase B when switch the energized phase to A phase from the B phase, the so-called residual current.

When switching from the energization pattern # 2 to the energization pattern # 3, the drive control unit 14 turns off both the switching element AL and the switching element N _AB H. Thereby, the phase current I _A generated by the back electromotive force of the A-phase winding La is regenerated to the power supply unit 3 through the free wheel diode of the switching element AH (FIG. 5 (c): regeneration mode).

(Energization pattern # 3)
In the energization pattern # 3, the drive control unit 14 controls the switching element BL (lower arm switching element) to be in an ON state, and performs PWM control of the switching element N _AB H (upper arm switching element). Thus, through the phase current I _B as an excitation current in the positive direction with respect to the B phase winding Lb. That is, in energization pattern # 3, the energized phase is the B phase and the non-energized phase is the A phase.

Therefore, as shown in FIG. 6, when both the switching element BL and the switching element N _AB H are in the ON state, the switching element N _AB H, the B-phase winding Lb, and the switching element BL are sequentially supplied from the power supply unit 3. flow phase current _{I B,} B phase winding Lb is excited (Fig. 6 (a): supply mode).

Further, when the switching element N _AB H performs PWM control, when the switching element BL is in the on state and the switching element N _AB H is in the off state, the phase current I _B flowing through the B phase winding Lb is , Through the return diodes of the switching element BL and the switching element N _AB L, and return to the B-phase winding Lb in the positive direction. That is, a closed loop is formed by the B-phase winding Lb, the switching element BL, and the return diode of the switching element N _AB L (FIG. 6B: return mode). Thereby, the excitation of the B-phase winding Lb is continued. On the other hand, the phase current I _A flowing through the A-phase winding La is regenerated to the power supply unit 3 via the free wheel diode of the switching element AH. That is, the drive control unit 14 forms a circuit including the free wheel diode of the switching device N _AB L, the A phase winding La, the free wheel diode of the switching device AH, and the power supply unit 3 during the PWM control of the switching device N _AB H. by, it is regenerated to the power supply unit 3 without recirculating phase current I _a flowing through the a-phase winding La in the three-phase inverter within 4-1. Phase current I _A regenerated to the power supply unit 3 remains in the A-phase when switching the current supply phase to the B phase from the A-phase, a so-called residual current.

When switching from the energization pattern # 3 to the energization pattern # 4, the drive control unit 14 turns off both the switching element BL and the switching element N _AB H. Thus, the phase current I _B generated by the counter electromotive force of the B phase winding Lb is regenerated as power source 3 a reflux diode of switch BH (regeneration mode).

(Energization pattern # 4)
In the energization pattern # 4, the drive control unit 14 performs PWM control of the switching element AH (upper arm switching element) and controls the switching element N _AB L (lower arm switching element) to be in the ON state. Thus, the phase current I _A as an excitation current in the negative direction flows to the A phase winding La. That is, in energization pattern # 4, the energized phase is the A phase and the non-energized phase is the B phase.

Therefore, as shown in FIG. 7, when both the switching element AH and the switching element N _AB L are in the ON state, the switching element AH, the A-phase winding La, and the switching element N _AB L are sequentially supplied from the power supply unit 3. flow phase current _{I A,} A-phase winding La is excited (Fig. 7 (a): supply mode).

Further, when the switching element AH is under PWM control, when the switching element AH is in the off state and the switching element N _AB L is in the on state, the phase current I _A flowing through the A-phase winding La is It passes through the return diode of the element N _AB L and the switching element AL and returns in the negative direction with respect to the A-phase winding La. That is, a closed loop is formed by the A-phase winding La, the return diode of the switching element AL, and the switching element N _AB L (FIG. 7B: return mode). Thereby, the excitation of the A-phase winding La is continued. On the other hand, the phase current I _B flowing through the B-phase winding Lb is regenerated to the power source 3 through the reflux diode of the switching element BL. That is, the drive control unit 14 includes a circuit composed of the return diode of the switching element AL, the A-phase wire La, the B-phase winding Lb, the return diode of the switching element BH, and the power supply unit 3 during PWM control of the switching element AH. by forming, it is regenerated to the power supply unit 3 without the phase current I _B flowing through the B-phase winding Lb refluxed in a three-phase inverter within 4-1. The power supply unit phase current I _B which is regenerated in 3 remains in phase B when switch the energized phase to A phase from the B phase, the so-called residual current.

When the drive control unit 14 switches from the energization pattern # 4 to the energization pattern # 1, both the switching element AH and the switching element N _AB L are turned off. Thereby, the phase current I _A generated by the back electromotive force of the A-phase winding La passes through the free wheel diode of the switching element N _AB H and is regenerated to the power supply unit 3 (FIG. 7 (c): regeneration mode).

  As described above, the drive control unit 14 causes the power supply unit 3 to regenerate the three-phase inverter 4-1 without causing the phase current flowing in the non-energized phase to flow back. Thereby, the drive control unit 14 can reduce the phase current flowing in the non-energized phase in the reflux mode. Therefore, the output can be improved by widening the conduction angle, and the braking torque due to the phase current in the regeneration section can be reduced, and the performance of the four-phase SR motor can be improved.

More specifically, in the conventional method, as the energization pattern corresponding to the energization pattern # 1, the switching element BH (upper arm switching element) is PWM-controlled and the switching element N _AB L (lower arm switching element) is turned on. Control to the state. For this reason, in the return mode, the A phase current (phase current I _a flowing through the A phase winding La) that is _a non-energized phase passes through the switching element N _AB L, the return diode of the switching element AL, and the A phase winding. Reflux to line La. Accordingly, in the non-energized section in which no current flows from the power supply unit 3 to the A-phase winding La and the B-phase winding Lb, the A-phase phase current that is a non-energized phase recirculates. A braking torque is generated, and the output of the SR motor M decreases.

  On the other hand, in the present embodiment, the drive control unit 14 causes the power source unit 3 to regenerate the phase current flowing in the non-energized phase without refluxing in the non-energized section. More specifically, when the drive control unit 14 performs PWM control of energization of one of the two phases (A phase and B phase, or C phase and D phase) that is the energized phase, the drive control unit 14 performs the PWM control. In the off period (non-energized period), the phase current flowing in the other phase that is the non-energized phase is regenerated in the power supply unit 3.

  For example, in the energization pattern # 1, the drive control unit 14 performs PWM control of the switching element of the lower arm and controls the switching element of the upper arm to the on state. Thereby, in the reflux mode, the phase current flowing in the non-energized phase is regenerated in the power supply unit 3 without being refluxed. Accordingly, the phase current of the A phase that is a non-energized phase is reduced, and the generation of braking torque is suppressed. Therefore, a decrease in the output of the SR motor M can be suppressed.

  In addition, although the case where energization pattern # 1-4 shown in FIGS. 3-7 was performed with respect to the switching element of the three-phase inverter 4-1 was demonstrated, it is the same also about the switching element of the three-phase inverter 4-2. You may control. That is, as shown in FIG. 8, the drive control unit 14 may regenerate the non-energized phase current to the power supply unit 3 in the non-energized section also in the three-phase inverter 4-2.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

For example, in the energization pattern # 2 of the above embodiment, the drive control unit 14 performs PWM control of the switching element AL (lower arm switching element) and controls the switching element N _AB H (upper arm switching element) to be in the on state. Also good. Thus, in the reflux mode, more efficiently, thereby regenerating the phase current I _B flowing through the B-phase winding Lb in the power supply unit 3. That is, in the return mode, the switching element AL is turned off, so that the component that returns to the B phase winding Lb via the switching element AL is eliminated from the phase current I _B flowing through the B phase winding Lb. be able to. Accordingly, the drive control unit 14 forms a circuit including the switching element BL, the B-phase winding Lb, the A-phase winding La, the free-wheeling diode of the switching element AH, and the power supply unit 3 during the PWM control of the switching element AL. by, it can be regenerated to the power supply unit 3 without recirculating phase current I _B flowing through the B-phase winding Lb.

DESCRIPTION OF SYMBOLS 1 Motor system 2 Motor control apparatus 4 Three-phase inverter 6 Control part 14 Drive control part M SR motor La A phase winding Lb B phase winding Lc C phase winding Ld D phase winding AH, AL, N _AB H, N _AB L, BH, BL Switching element CH, CL, N _CD H, N _CD L, DH, DL Switching element

Claims (4)

A motor control device that rotationally drives the SR motor by switching energization from the power source to the windings corresponding to each phase of the four-phase SR motor,
A pair of three-phase inverters connected to the A-phase and B-phase two-phase windings and the C-phase and D-phase two-phase windings;
A control unit for controlling a phase current flowing in the winding by controlling a plurality of switching elements in each of the three-phase inverters in an on state or an off state;
With
The said control part makes the said power supply part regenerate without recirculating the phase current which is flowing into the non-energized phase.   In the PWM control of energization of at least one of the two phases that is the energized phase, the control unit supplies the phase current that flows to the other phase that is the non-energized phase during the off period of the PWM control. The motor control device according to claim 1, wherein the motor control device is regenerated by a power supply unit.   The control unit performs PWM control of the switching element of the lower arm among the plurality of switching elements and controls the switching element of the upper arm to be in the ON state, thereby performing PWM control of the phase current flowing in the energized phase and de-energizing. The motor control device according to claim 1, wherein a phase current flowing in a phase is regenerated in the power supply unit.   The motor control device according to claim 3, wherein the switching element of the lower arm that performs PWM control is a switching element of the lower arm that is connected to a connection point of the two-phase winding.

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