JP2008148377A - Sr motor drive and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an SR motor drive control method for driving a plurality of motors by a small number of inverters. <P>SOLUTION: The SR motor drive connecting a first power supply (vdc1) and a second power supply (vdc2) with a first SR motor (SRM1) and a second SR motor (SRM2) is connected with a power supply side joint (CP1) connecting the first and second power supplies in series, and a motor side joint (CP2) connecting the coils (LU1, LV1, LW1) of the first SR motor in series with the coils (LU2, LV2, LW2) of the second SR motor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an SR motor driving device and a control method thereof.

In recent years, motorization of automobiles has progressed. Advantages include diversification of vehicle control in addition to improved fuel consumption. For example, in the event of an eccentric imbalance of a tire, in order to suppress vibrations of the body, suspension, etc., the vehicle is stabilized by motor drive control on the premise of a system that can independently drive the four wheels of the vehicle by a motor. A method (see Patent Document 1) has been proposed. Specifically, the proposed technique estimates the eccentric amount of each wheel based on at least one of the current value and the voltage value of the current flowing through each motor in the vehicle system shown in FIG. The unbalance force generated in each wheel is estimated based on the amount of eccentricity and the rotational speed of each wheel, and the vibration of the vehicle is suppressed by canceling the difference in unbalance force.
Japanese Unexamined Patent Publication No. 2006-60913

  However, since the conventional system described above requires four motors, it is difficult to spread from the viewpoint of cost. By the way, although one inverter is normally connected with respect to one motor, since an inverter is comprised with an electronic component, it is weak to a mechanical vibration and an installation place is restricted. Further, the switching elements (power conversion elements) constituting the inverter need to be cooled, and some kind of cooling device (cooling equipment, piping, etc.) is also required. Therefore, if the cost can be reduced by reducing the number of inverters, it should contribute to the spread of automobiles incorporating new controls.

  The objective of this invention is providing the SR motor drive control apparatus which can drive a several motor with few inverters (power converter device), and its method. That is, an object is to reduce the cost of an electric vehicle that requires a plurality of motors, for example, by reducing the number of inverters.

In order to solve the above-described problems, an SR (switched reluctance) motor driving device according to the first invention is provided.
An SR motor driving device (circuit or the like) that connects a first power source, a second power source, a first SR (switched reluctance) motor, and a second SR motor,
A power supply side connection point in which the first power supply and the second power supply are connected in series, and a motor side connection point in which the coil (stator coil) of the first SR motor and the coil of the second SR motor are connected in series. And are connected,
It is characterized by that.

The SR motor driving device according to the second invention is
Of the first and second SR motors, all the coils in at least one SR motor are connected to be excited by the first power supply and demagnetized by the second power supply.
It is characterized by that.

The SR motor driving device according to the second invention is
The voltage of the first power supply and the voltage of the second power supply are set to different voltage values.
It is characterized by that.

An SR motor driving apparatus according to the fourth invention is
A plurality of switching elements;
At least one power storage device provided between any one of the plurality of switching elements and any one of the first power source and the second power source (that is, connected to the switching element and the power source). Capacitors)
Is further provided.

An SR motor driving apparatus according to the fifth invention is
In the SR motor drive device according to claim 1,
Among the first and second SR motors, a part of the coils in at least one SR motor is excited or demagnetized by another coil in the SR motor (that is, a coil other than the part of the coils). Connected to be excited or demagnetized by a power source different from the power source to be
It is characterized by that.

An SR motor driving apparatus according to the sixth invention is
A power supply voltage measuring unit for measuring a power supply voltage of the first and second power supplies;
A power supply voltage control unit that controls at least one of the first and second SR motors so that the power supply voltage measured by the power supply voltage measurement unit matches a target value (for example, a power supply voltage measurement value and a target value The deviation is given to a (voltage / current) command value generator in the SR motor driving device, that is, feedback control is performed),
Is further provided.

An SR motor driving apparatus according to the seventh invention is
The power supply voltage control unit performs a control operation during a period in which the stator teeth and the rotor teeth of the first or second SR motor are not opposed to each other.
It is characterized by that.

An SR motor driving device according to the eighth invention is
(In this case, each of the first and second SR motors includes a rotor.)
The power supply voltage control unit performs a control operation when the rotor of the first or second SR motor is stopped.
It is characterized by that.

An SR motor driving device according to the ninth invention is
The first and second SR motors have different numbers of phases,
It is characterized by that.

An SR motor driving device according to the tenth invention is
The SR motor driving device further includes at least a third SR motor,
(The first and second SR motors and the at least third SR motor are three or more independent SR motors) one end of each coil of the at least third SR motor; The motor side connection point is connected.
It is characterized by that.

As described above, the solution of the present invention has been described as an apparatus. However, the present invention can be realized as a method, a program, and a storage medium that stores the program substantially corresponding to these, and the scope of the present invention. It should be understood that these are also included.
For example, a method according to an eleventh aspect of the present invention that realizes the present invention as a method is:
A power supply side connection point in which the first power supply and the second power supply are connected in series, and a motor side connection point in which the coil of the first SR motor (stator coil) and the coil of the second SR motor are connected in series are connected. A method of controlling an SR motor driving device (circuit, etc.),
A power supply voltage measuring step of measuring a power supply voltage of the first and second power supplies with a voltmeter;
A power supply voltage control step of controlling at least one of the first and second SR motors so that the measured power supply voltage matches a target value;
It is characterized by having.

The SR motor drive device control method according to the twelfth aspect of the present invention comprises:
The power supply voltage control step performs a control operation during a period in which the stator teeth and the rotor teeth of the first or second SR motor are not opposed to each other.
It is characterized by that.

Further, a control method of the SR motor driving device according to the thirteenth invention is as follows:
The power supply voltage control step performs a control operation when the rotor of the first or second SR motor is stopped at the time.
It is characterized by that.

  According to the first invention, in the SR motor drive circuit that connects the first power source, the second power source, and the first SR motor and the second SR motor, the first power source and the second power source. Are connected in series to the power supply side connection point and the motor side connection point in which the coil of the first SR motor and the coil of the second SR motor are connected in series. Two SR motors can be driven with almost no change, and the number of inverters can be reduced. As a result, the cost of an automobile system that requires a plurality of motors can be reduced.

  According to the second invention, among the SR motors, all the coils in at least one SR motor are connected by being excited by the first power supply and demagnetized by the second power supply. Therefore, in addition to the first effect, the excitation voltage and the demagnetization voltage are unified in all the coils, so that driving with less torque ripple is possible.

  According to the third invention, since the voltage of the first power supply and the voltage of the second power supply have different voltage values, optimum voltage conditions are set even when the two motors are used for different applications. can do. Specifically, when one is used as a generator and the other is used as a drive motor, the generator side can be a fixed voltage power source, and the drive motor side can be a variable voltage power source. A cost SR motor drive circuit can be provided.

  According to the fourth invention, the SR motor drive circuit is an SR motor drive circuit composed of a plurality of switching elements, and includes a power storage device (a capacitor or the like) between the power source and the switching elements. If the power storage means is a capacitor, the regenerative power of the motor can be stored instantaneously, and the current response can be improved. As a result, the operating range of the motor can be expanded.

  According to the fifth invention, among the SR motors, a part of the coils in at least one SR motor is connected to be excited or demagnetized by the power source different from the other coils. For example, when the motor is applied to a left and right independently driven electric vehicle, it is difficult to cause voltage imbalance between the two power supplies, and an effect of enabling stable driving is obtained.

  According to the sixth invention, the SR motor drive circuit is an SR motor drive circuit provided with a power supply voltage measuring device, and controls the drive of the SR motor so that the power supply voltage matches the target value. When it is desired to change the power supply voltage in order to widen the operating range, or since it is not necessary to add a new voltage stabilizing device to balance the two power supply voltages, an increase in cost can be suppressed.

  According to the seventh invention, since the SR motor drive control is performed during a period in which the stator teeth and the rotor teeth of the SR motor are not opposed to each other, in addition to the sixth effect, the voltage control is performed while suppressing the fluctuation of torque. can do.

  According to the eighth invention, since the SR motor drive control is performed when the SR motor rotor is stopped, in addition to the sixth effect, the voltage imbalance is corrected without causing any trouble in the draft. And you can prepare for the next run.

  According to the ninth invention, since the two SR motors have different numbers of phases, for example, even a two-phase motor whose starting direction is not fixed is used for a purpose such as a generator. The system is established. Since the two-phase motor can be driven with a smaller number of switching elements than the three-phase motor, the cost can be further reduced.

  According to the tenth invention, the SR motor is three or more independent SR motors, and connects the connection point and one end of each coil of the SR motor, so that the effect of the present invention is not impaired. Three or more motors can be driven at low cost.

  In order to contribute to an understanding of the present invention, the configuration and operation of a conventional SR motor drive circuit will be described prior to the description of the embodiments according to the present invention. FIG. 9 is a drive circuit diagram of a generally well-known SR motor (three-phase) according to the prior art. As shown in the figure, the drive circuit includes a power supply Vdc, a smoothing capacitor C1, U-phase switching elements SW1 and SW2, and diodes D1 and D2, V-phase switching elements SW3 and SW4, and diodes D3, D4, and W-phase. Switching elements SW5 and SW6 and diodes D5 and D6 are provided. Furthermore, the U-phase, V-phase, and W-phase terminals are connected to coils LU, LV, and LW in the SR motor SRM.

  As an example of a conventional SR motor, FIG. 10A shows a cross-sectional view of an SR motor having 12 pole teeth in the stator and 8 pole teeth in the rotor. In this SR motor SRM, one coil is wound around each tooth of the stator St, and there are 12 coils in total. Since it is a three-phase motor, there are four coils per phase. For convenience of drawing and explanation, although omitted in FIG. 9, for example, focusing on the U phase, the four coils LU1-LU4 are connected in series or in parallel to each other, and the collective coil representing the whole of these coils LU1-LU4 The LU is connected to the circuit of FIG. Similarly for the other phases, the V phase includes four coils LV1 to LV4 and a collective coil LV representing the whole of these four coils, and has the same connection relationship. In the W phase, there are four coils LW1 to LW4 and a collective coil LW representing the whole of these four coils, which have the same connection relationship. A rotor angle θ is an angle formed by a line segment X (phase start angle) extending in the horizontal direction from the center CTR of the rotor Rt and a line segment Y extending from the center CTR of the rotor Rt through the center of the target tooth Te. In order to simplify the drawing and explanation, the illustration and explanation will be given focusing on one target tooth Te, but the same applies to other teeth.

  Next, the power running operation of the motor will be described. Here, the description will be given focusing on the U phase. FIG. 10B is an enlarged view showing a part of the teeth of the coil LU1 and the rotor Rt in an enlarged manner. At the excitation start angle θon illustrated in FIG. 10B, the switching elements SW1 and SW2 of the circuit of FIG. 9 are turned on. As a result, a current flows through the coil LU1, and the teeth of the stator St and the teeth of the rotor Rt are attracted to each other by the magnetic flux generated by the coil LU1, so that reluctance torque is generated. Further, as shown in FIG. 10 (c), when the target teeth Te of the stator St and the rotor Rt are substantially opposed, that is, at the excitation stop angle θoff, the switching elements SW1 and SW2 are turned off. Thereby, the magnetic flux generated in the target tooth Te is demagnetized.

  In this case, the current during excitation and the current during demagnetization are in the same direction. However, since it is necessary to change the polarity of the coil voltage, the switching elements SW1 and SW2 are turned on at the time of excitation to set the upper end of the coil in FIG. 9 to “+”, and the switching elements SW1 and SW2 are turned off at the time of demagnetization. The upper end of the coil in FIG. 9 is set to “−” by D2. That is, in this example, since it is necessary to flow the excitation and demagnetization currents to the same power source, a circuit configuration as shown in FIG. 9 is required. The other phases have the same configuration. A total of six wires are required, two for each phase coil.

  Next, another conventional circuit will be described. FIG. 11 is a drive circuit diagram of an SR motor (four phases) according to another conventional technique. However, this circuit configuration is applicable when the number of phases of the SR motor is an even number phase such as two phases or four phases. As shown in the figure, the SR motor driving circuit according to the prior art is provided with a first power supply Vdc1, a second power supply Vdc1, smoothing capacitors C1, C2, switching elements SW1-SW4, and diodes D1-D4. Further, the SR motor SRM is provided with a-phase, b-phase, c-phase, and d-phase coils La, Lb, Lc, and Ld.

  In this conventional circuit configuration, two power supplies are provided and connected in series, and the connection point and one end of each phase coil are connected. Accordingly, for example, when the positional relationship between the a-phase stator teeth and the rotor teeth is as shown in FIG. 10B, when the a-phase is excited, the switching element SW1 is turned on and the first power supply Vdc1 and the other end of the coil When degaussing, the switching element SW1 is turned off and the second power supply Vdc2 and the other end of the coil are connected by the diode D2. Since one end of the coil is already fixedly connected, only the other end of the coil needs to be switched. Therefore, in the configuration of FIG. 9, two wires are required for each phase coil, and a total of eight wires are required for four phases. On the other hand, 5 is enough.

  By the way, as described above, an electric vehicle often uses a plurality of motors. Therefore, assuming that the conventional example is used for a series hybrid vehicle that generates electric power by rotating the engine as shown in FIG. 12 and drives the motor by this electric power, the problems of the prior art will be described again in detail. . FIG. 12 is a configuration diagram of an electric vehicle equipped with two conventional SR motors. The motor / generator uses the four-phase SR motors SRM1 and SRM2 shown in FIG. 11, and these motors are driven by an inverter (drive circuit) INV. The rotor shaft of the SR motor SRM1 is mechanically connected to the output shaft of the engine ENG. The other SR motor SMR2 is a drive motor whose rotor shaft is mechanically connected to the wheel shaft via a gear. In order to perform efficient operation with this system, it is desirable to generate power by controlling the SR motor SRM1 as a generator so as to maintain the engine ENG at an efficient rotational speed. One of the wheel shafts needs to change its rotation speed every moment according to a driver's request. The power supply voltage of the SR motor SRM2 as a drive motor for changing the number of revolutions, for example, is relatively easy to obtain a torque compared to a high rotation even if the current response is poor at a low rotation, and the voltage of the inverter is unnecessarily high. Power conversion efficiency is reduced. Therefore, it is better to drive the motor with the minimum necessary power supply voltage during low rotation. However, torque cannot be obtained unless the current response is improved at high speeds. Therefore, a high voltage is required. When the configuration of FIG. 11 is viewed in consideration of the above, the voltage values cannot be changed from each other even though there are two power supplies BAT1 and BAT2. In other words, even if the voltage of one power supply is fixed and the other is changed, not only the excitation voltage of each phase coil varies in one motor and torque ripple occurs, but also the effect of answering the above requirements Cannot be obtained. It is out of the question to prepare another power source for changing the voltage value because the cost becomes very high.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, similar elements / members are denoted by the same reference numerals. FIG. 1 is a circuit diagram of an SR motor drive circuit according to Embodiment 1 of the present invention. As shown in the figure, in the SR motor driving circuit according to the present embodiment, the power supply side connection point CP1 in which the first power supply Vdc1 and the second power supply Vdc2 are connected in series, and the first and second SR motors SRM1 and SRM2 are connected. A motor-side connection point CP2 in which one end of each coil is connected is connected. The SR motors SRM1 and SRM2 are provided with position sensors PS and PS2, respectively, for detecting the position of the rotor (that is, the salient pole / tooth phase angle) constituting each motor.

  In this way, by directly connecting the power supply side connection point CP1 and the motor side connection point CP2, the number of wirings can be reduced as compared with preparing the circuit of FIG. 9 as the conventional example for two motors, The number of switching elements and the number of diodes can be halved. Further, the excitation power supply and the demagnetization power supply are configured to be unified in all coils of one motor.

  Next, the operation will be described. The coils LU1, LV1, and LW1 of the first SR motor SRM1 are excited by being connected to the first power supply Vdc1 by the switching elements SW1, SW3, and SW5, and the second power supply Vdc2 by the diodes D2, D4, and D6. Connect and degauss. On the other hand, the coils LU2, LV2, and LW2 of the second SR motor SRM2 are excited by being connected to the second power source Vdc2 by the switching elements SW2, SW4, and SW6, and the first power source by the diodes D1, D3, and D5. Demagnetization is performed by connecting to Vdc1. Further, smoothing capacitors C1 and C2 are provided in parallel with the first and second power sources Vdc, respectively. The U-phase driving circuit includes switching elements SW1 and SW2 and diodes D2 and D2. The V-phase drive circuit includes switching elements SW3 and SW4 and diodes D3 and D4. Further, the W-phase drive circuit includes switching elements SW5 and SW6 and diodes D5 and D6.

  An improvement point is demonstrated supposing that this invention was used for the series hybrid similar to description of a prior art. It is assumed that the first SR motor SRM is used as a generator and the second SR motor SRM2 is used as a drive motor. The voltage of the first power supply Vdc1 connected to the first SR motor SRM1 is fixed at a convenient voltage value at a rotational speed that matches the maximum efficiency point of the engine. The second power supply Vdc2 connected to the other SR motor SRM2 makes the voltage variable in order to change the rotational speed of the SR motor SRM2. Even in such a case, in the circuit according to the present embodiment, the excitation voltage and the demagnetization voltage of each phase coil are uniform for all the coils in one motor, so that the torque ripple is kept low and the switching element is easily controlled. It is. Therefore, cost reduction can be realized by reducing the number of wirings, the number of switching elements, and the number of diodes without degrading quality.

  As described above, in this embodiment, since the two SR motors SRM1 and SRM2 can be driven with almost no change in the configuration of the conventional SR motor drive circuit, the number of inverters (such as switching elements and diodes) can be reduced. And cost can be reduced. In addition, since the voltage of the first power supply Vdc1 and the voltage of the second power supply Vdc2 are different from each other, optimum voltage conditions can be set even if the two motors are used for different applications. It is possible to provide a low-cost SR motor drive circuit applicable to a hybrid vehicle or the like. Further, all the coils LU1, LV1, and LW1 in the first SR motor SRM1 are connected so that they are excited by the first power supply Vdc1 and demagnetized by the second power supply Vdc2. On the other hand, in the second SR motor SRM2, the relationship between excitation and demagnetization is reversed. Therefore, in addition to the effect of the first invention, the excitation voltage and the demagnetization voltage are unified in all coils, so that it is possible to drive with less torque ripple.

  FIG. 2 is a circuit diagram of an SR motor drive circuit according to the second embodiment. In the present embodiment, the SR motor drive circuit of the first embodiment is improved. 2, the same reference numerals as those in FIG. 1 denote the same components as those in FIG. In the SR motor drive circuit according to the present embodiment, the first SR motor SRM1 in the circuit of FIG. 1 is used as a generator and the second SR motor SRM2 is used as a drive motor as in the first embodiment. In this system, when the second SR motor SRM2 is used at a high rotational speed, the voltage of the first power supply Vdc1 is increased, but the voltage of the second power supply Vdc2 operates as a generator. Since the voltage is set to be convenient for the SRM1, the demagnetizing voltage is too low for the second SR motor SRM2 operating as the drive motor, and the current responsiveness may be deteriorated and the torque may be reduced.

  As a countermeasure, in this embodiment, as shown in FIG. 2, a relatively small-capacity smoothing capacitor C3 connected in parallel with the smoothing capacitor C1 is provided. Further, a switching element SW7 provided in the middle of wiring connecting the smoothing capacitors C1 and C3, that is, the common positive electrode bus Pb, for switching charge accumulation / discharge to the smoothing capacitor C3, and the switching element SW7 Is provided with a control circuit 3 for controlling on / off. The demagnetizing current of the second SR motor SRM2 flows through the smoothing capacitor C3. If the switching element SW7 is turned off, the voltage of the smoothing capacitor C3 rises according to the amount of current flowing in, and the demagnetizing current can be extinguished quickly. However, if this is repeated, the voltage of the smoothing capacitor C3 will rise without limit. In order to prevent this, the following control is performed in this embodiment.

  FIG. 3 is a timing chart showing the operation timing of the switching element used in Embodiment 2 of the present invention. FIG. 3 shows the operation timing of each switching element for shortening the current falling time of the second SR motor SRM2 when the first SR motor SRM1 is used at a low rotation and the SRM2 is used at a high rotation. It is. First, regarding the inductance of the U-phase coil LU2 of the second SR motor SRM2, the peak of the inductance appears in a short cycle due to high rotation. On the other hand, the inductance peaks of the U-phase and V-phase coils LU1 and LV1 of the first SR motor SRM1 appear in a longer cycle than LU2.

  By the way, in the SR motor, when the stator teeth and the rotor teeth are not opposed to each other, the inductance becomes low, and becomes a flat portion in each inductance curve shown in FIG. When the stator teeth and the rotor teeth are in such a positional relationship, torque is not effectively generated even if the coil is energized. A characteristic of this control is that the charge of the smoothing capacitor C3 is returned to the second power supply Vdc2 during this period. Specifically, when the stator teeth and the rotor teeth of the first SR motor SRM1 operating as a generator are in the non-opposing positions, the switching elements SW1 and SW3 that are not used are turned on to turn on the smoothing capacitor C3. The charge is returned to the second power supply Vdc2. As shown in FIG. 3, charges are accumulated in the smoothing capacitor C3 during the time interval t1, and switching is performed by applying an ON signal to the gate (not shown) of the switching element SW1 during the time interval t2. The element SW1 is turned on, and the stored charge of the smoothing capacitor C3 flows to the second power supply Vdc2. If the above method is used, in addition to the effects described in the first embodiment, the current response can be improved, so that torque can be effectively generated at high rotation. As described above, the smoothing capacitor C3 functions not only for smoothing but also as a power storage means for moving charges between a plurality of power sources.

  The switching element SW7 may be a diode that is cheaper than a semiconductor element such as an IGBT that is generally expensive. In the case of a diode, since the control is unnecessary (that is, the control circuit 3 is not required), the above effect can be realized more easily. As described above, according to the present embodiment, the SR motor drive circuit is an SR motor drive circuit composed of a plurality of switching elements, and includes a power storage device between the power source and the switching elements. If a capacitor is used, the regenerative power of the motor can be temporarily stored and the current response can be improved. Therefore, an effect that the operating range of the motor can be expanded is obtained. Furthermore, since voltage control can be performed by switching of the motor drive circuit, it is not necessary to use another device for preventing the voltage of the smoothing capacitor C3 from being raised excessively.

  In the first and second embodiments, examples in which two motors are used for different applications have been described. FIG. 4 is a configuration diagram of a left and right independent drive system suitable for mounting a motor drive device according to the present invention. As shown in the figure, the case where the present invention is applied to a left and right independent drive system will be described. The basic circuit configuration is the same as in FIG. In the case of left and right independent drive, the voltages of both power sources Vdc1 and Vdc2 should be equal, but two SRs can be obtained depending on whether the friction coefficient on the road is different between right and left, road surface unevenness, or one-way turning. It is conceivable that the power supply voltage supplied to the motors SRM1 and SRM2 becomes uneven. Here, a method for equalizing both power supply voltages according to the present invention will be described.

  FIG. 5 is a diagram showing an example of a phase current waveform used in Example 3 according to the present invention. FIG. 5A shows an example of the inductance of one coil by the SR motor driving circuit, and FIG. 5B shows an example of the phase current of the coil. Further, as shown in FIG. 1, voltmeters V1 and V2 are connected to the first and second power sources Vdc1 and Vdc2, and the potential difference between the measured voltages v1 and v2 is monitored by the control devices 1 and 2. . If there is no voltage difference between the two power supplies, the SR motor is driven under operating conditions that provide maximum efficiency. However, if there is a voltage difference, the excitation start angle, excitation stop angle, maximum current value, etc. of one motor are shifted from the maximum efficiency operating point so as to correct the voltage difference between the power supplies. Specifically, in FIG. 5, when the excitation start angle, the excitation stop angle, and the maximum current value are θon0, θoff0, and Ip0, respectively, as operating conditions for obtaining the maximum efficiency, the operating point is set to increase the current from the coil. Change to θon1, θoff1, and Ip1. In FIG. 5, in addition to the degaussing current of the coil, current is supplied in a region where the time change dL / dt of the inductance is negative to obtain a generated current. As a result, negative torque is generated, but the energizing current is increased and the positive torque is increased in the region where dL / dt is positive, so that the average torque remains the same as before the operating point is changed.

  For example, when the circuit of FIG. 1 is applied to the left and right independent drive, if v1> v2, the control circuit 1 changes the operating point of the first SR motor SRM1 and the second control is performed. A large amount of current is allowed to flow through the power supply Vdc2. Conversely, if v1 <v2, the control circuit 2 changes the operating point of the second SR motor SRM2 so that a large amount of current flows through the first power supply Vdc1.

  Further, as a method of changing the operating point, there is a method of energizing positively during a period in which the stator teeth and the rotor teeth are not opposed to each other and torque is difficult to generate. This will be described with reference to FIG. FIG. 6 is a diagram showing another phase current waveform example used in the third embodiment of the present invention. FIG. 6A shows an example of the inductance of one coil by the SR motor driving circuit, and FIG. 6B shows an example of the phase current of the coil. In FIG. 6, without changing the excitation stop angle θoff0, the excitation start angle is advanced to θon1. To further increase the current, the maximum current value is increased to Ip1. This balances the two power supply voltages.

  As described above, according to the present invention, since it is not necessary to newly add a voltage stabilizing device in order to balance the two power supply voltages, the operating range can be expanded without increasing the cost. Further, if voltage stabilization control is performed during a period in which the stator teeth and rotor teeth of the SR motor are not opposed to each other, the torque is not affected, and therefore voltage control can be performed without causing torque ripple. Note that voltage stabilization control may be performed when the vehicle is parked or when the brake is operated as long as the potential difference between the two power supplies does not significantly affect traveling.

  Next, another embodiment according to the present invention will be described. FIG. 7 is a circuit diagram of an SR motor drive circuit according to Embodiment 4 of the present invention. FIG. 7 shows wiring in which only the V phase of the coils of the first SR motor SRM1 and the second SR motor SRM2 is exchanged. That is, in the V phase, the switching element SW3 of the upper arm controls the conduction of the coil LV2 of the second SR motor SRM2, and the switching element SW4 of the lower arm controls the conduction of the coil LV1 of the first SR motor SRM1. . In the circuit as shown in FIG. 7, for example, when the road surface is bad and the load is reduced only on one wheel, the rotation of the motor on the light load side may increase and current may not flow as expected. At this time, since the coils are interchanged between the two motors as shown in FIG. 7, surplus power can be injected into the motor having a large load on the opposite side. This makes it easier to balance the power supply voltages. Further, even if one of the power supplies fails, the configuration shown in FIG. 7 can energize both motors, so that the running is more stable than when one wheel is completely unusable. As described above, according to the present embodiment, when applied to a left and right independently driven electric vehicle, it is difficult to cause voltage imbalance between the two power supplies, and an effect of enabling stable driving is obtained.

  Next, another embodiment according to the present invention will be described. FIG. 8 is a circuit diagram of an SR motor drive circuit according to Embodiment 5 of the present invention. FIG. 8 illustrates an example in which the number of phases differs between two motors. Although the operation and the like are the same as those of the system described so far, the two-phase motor has a merit that the number of switching elements of the inverter is reduced, but there is a problem that the starting direction is not determined. However, if the SRM2, which is a two-phase motor, is used not as a drive motor but as an auxiliary motor driven by a generator or another drive motor, there is no need to determine the starting direction with a two-phase motor. Therefore, this embodiment is one measure for reducing the cost. As described above, in the present embodiment, the two SR motors SRM1 and SRM2 have different numbers of phases, so that the cost can be further reduced by reducing the number of phases of one of the motors.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each part, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of parts, means, steps, etc. can be combined or divided into one. Is possible. Although the embodiments have been described with respect to two motors, it should be noted that the present invention is applicable to more than two motors.

It is a circuit diagram of the SR motor drive circuit by Example 1 of this invention. It is a circuit diagram of the SR motor drive circuit by Example 2 of this invention. It is a timing chart which shows the operation timing of the switching element used for Example 2 of the present invention. It is a block diagram of the left-right independent drive system suitable for mounting of the motor drive device by this invention. It is a figure which shows the example of a phase current waveform used in Example 3 by this invention. It is a figure which shows another example of a phase current waveform used in Example 3 by this invention. It is a circuit diagram of the SR motor drive circuit by Example 4 of this invention. It is a circuit diagram of the SR motor drive circuit by Example 5 of this invention. It is a drive circuit diagram of SR motor (three phases) by a prior art. It is sectional drawing of the SR motor by a prior art. It is a drive circuit diagram of SR motor (4 phases) by another prior art. It is a block diagram of the electric vehicle carrying two SR motors by a prior art.

Explanation of symbols

1, 2, 3, 4 Control device BAT1, BAT2 Power supply C1, C2, C3 Smoothing capacitor CP1 Power supply side connection point CP2 Motor side connection point D1-D6 Diode ENG Engine INV Inverter La, Lb, Lc, Ld Coil SRM1 First SR motor SMR2 Second SR motor LU1-LU4 Coil LV1-LV4 Coil LW1-LW4 Coil LU, LV, LW Collective coil PS1, PS2 Position sensor Rt Rotor CTR Center St Stator Te Target teeth SW1-SW7 Switching element Pb Positive electrode bus V1 , V2 Voltmeter Vdc power supply Vdc1 first power supply Vdc2 second power supply X, Y line segment θ rotor angle θon excitation start angle θoff excitation stop angle θ _OFF excitation stop angle θoff0 excitation stop angle

Claims (13)

An SR motor driving device for connecting a first power source, a second power source, a first SR motor, and a second SR motor,
A power supply side connection point in which the first power supply and the second power supply are connected in series, and a motor side connection point in which the coil of the first SR motor and the coil of the second SR motor are connected in series are connected. ing,
SR motor drive device characterized by that. In the SR motor drive device according to claim 1,
Of the first and second SR motors, all the coils in at least one SR motor are connected to be excited by the first power supply and demagnetized by the second power supply.
SR motor drive device characterized by that. In the switched reluctance motor drive device according to claim 1 or 2,
The voltage of the first power supply and the voltage of the second power supply are set to different voltage values.
SR motor drive device characterized by that. In the SR motor drive device according to any one of claims 1 to 3,
A plurality of switching elements;
At least one power storage device provided between any one of the plurality of switching elements and any one of the first power source and the second power source;
An SR motor drive device further comprising: In the SR motor drive device according to claim 1,
Among the first and second SR motors, some coils in at least one SR motor are excited or demagnetized by a power source different from a power source in which other coils in the SR motor are excited or demagnetized. Connected to be
SR motor drive device characterized by that. In the SR motor drive device according to any one of claims 1 to 5,
A power supply voltage measuring unit for measuring a power supply voltage of the first and second power supplies;
A power supply voltage control unit that controls at least one of the first and second SR motors so that the power supply voltage measured by the power supply voltage measurement unit matches a target value;
An SR motor drive device further comprising: In the SR motor drive device according to claim 6,
The power supply voltage control unit performs a control operation during a period in which the stator teeth and the rotor teeth of the first or second SR motor are not opposed to each other.
SR motor drive device characterized by that. In the SR motor drive device according to claim 6,
The power supply voltage control unit performs a control operation when the rotor of the first or second SR motor is stopped.
SR motor drive device characterized by that. In the SR motor drive device according to any one of claims 1 to 3,
The first and second SR motors have different numbers of phases,
SR motor drive device characterized by that. In the SR motor drive device according to any one of claims 1 to 3,
The SR motor driving device further includes at least a third SR motor,
One end of each coil of the at least third SR motor and the motor side connection point are connected,
SR motor drive device characterized by that. An SR motor to which a power supply side connection point in which a first power supply and a second power supply are connected in series, and a motor side connection point in which a coil of a first SR motor and a coil of a second SR motor are connected in series are connected A method for controlling a drive device, comprising:
A power supply voltage measuring step of measuring a power supply voltage of the first and second power supplies with a voltmeter;
A power supply voltage control step of controlling at least one of the first and second SR motors so that the measured power supply voltage matches a target value;
A control method for an SR motor drive device, comprising: In the control method of the SR motor drive device according to claim 11,
The power supply voltage control step performs a control operation during a period in which the stator teeth and the rotor teeth of the first or second SR motor are not opposed to each other.
A control method for an SR motor driving device. In the control method of the SR motor drive device according to claim 11,
The power supply voltage control step performs a control operation when the rotor of the first or second SR motor is stopped at the time.
A control method for an SR motor driving device.

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