JPH05207782A - Driver for variable reluctance motor - Google Patents

Abstract

PURPOSE:To improve high speed rotation characteristics through simple constitution by interconnecting the phase windings of a variable reluctance motor in star, connecting the neutral point thereof with the neutral voltage point of a DC power supply circuit, sequentially connecting each phase winding with the positive or negative pole of the DC power supply in predetermined combination, and then conducting them. CONSTITUTION:Phase Windings La, Lb, Lc of a variable reluctance motor SRM are interconnected in star and the neutral N thereof is connected with the neutral voltage point M of a power supply circuit 13. A conducting circuit 15 is arranged in six arm bridge. At the time of conduction/interruption through transistors TR1a-Tr1c in the conducting circuit 15, one of capacitors C1, C2 in the power supply circuit 13 functions as a power supply capacitor while the other functions as a regenerated charge storing capacitor. Since the wire harness for the motor SRM and a driving section 10 requires only four lead wires la, lb, lc, ln, the driving section 10 can be downsized and since the phase winding current rises steeply, output characteristics are improved at the time of high speed rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a variable reluctance motor.

[0002]

2. Description of the Related Art A variable reluctance motor (hereinafter referred to as an SR motor) has an advantage that a large torque can be obtained because a stator and a rotor are made of iron and a high magnetic flux density can be obtained. Is large and it is difficult to rapidly increase or decrease the exciting current. In particular, since it is not excellent in output characteristics (rotation speed-torque characteristic) at high speed rotation, it is often not used for high speed rotation but used as a motor for medium to low speed rotation.

In the SR motor having such characteristics, each phase winding is energized by a driving device from a DC power supply circuit in a predetermined circulation order to be rotationally driven. When the energization is cut off, magnetic energy [J] of 1/2 × H × i ² (i: phase winding current at the moment when the energization is stopped, H: phase winding inductance) is applied to the phase winding. Has been accumulated. The drive device is provided with a regeneration / storage circuit that regenerates the magnetic energy as an electric charge and stores it in a capacitor so that the magnetic energy can be quickly recovered and a negative torque is not generated with respect to the rotation of the SR motor.

For example, as shown in the column (A) of FIG. 8, main components are energization control circuits 110a, 110b, 110c for controlling energization from the DC power supply 102 to the phase windings La, Lb, Lc. Driving device 100 for three-phase SR motor
It has been known. In this type of drive device 100,
The rotor is continuously rotated by energizing the phase windings La to Lc in a predetermined circulation order to excite the magnetic poles (not shown) of the stator. For example, in the circulation order of A phase → B phase → C phase → A phase, two transistors (11
2a · 114a), (112b · 114b), (112
The driving device 100 rotationally drives the SR motor by sequentially turning on and off (c · 114c) simultaneously. Each of the transistors (112a / 114a) to (112c /
114c) is turned off, the magnetic energy accumulated in the excited phase windings La to Lc is used as electric charge to convert the commutation diodes (116a / 118a) and (116b / 1).
DC power supply 1 via 18b) and (116c / 118c)
02 by regenerating the capacitor 104 and supplying the regenerative electric charge to the phase windings La to Lc to be energized next, generation of negative torque is suppressed and power loss is reduced. In this case, a capacitor having a large capacity is used to prevent an overvoltage when the power supply is cut off.

Further, as shown in the column (B) of FIG. 8, a driving device 200 for a three-phase SR motor which employs a step-down chopper circuit 210 is also known, and the step-down chopper circuit 210 allows the capacitor of the DC power supply 202 to be connected. By preventing the overvoltage from being applied to the 204 and the regenerative capacitor 212, a capacitor having a relatively small capacity can be adopted.

In this driving device 200, when the energizing transistors 214a, 214b, 214c are turned off,
The magnetic energy stored in the phase windings La to Lb is stored in the regenerative capacitor 212 as electric charge via the commutation diodes 216a, 216b, 216c. As a result, the voltage of the regenerative capacitor 212 increases. When the voltage exceeds a predetermined limit voltage, the switching transistor 220 is turned on by a command from the chopper control circuit 218.
Then, a current flows from the regenerative capacitor 212 to the power supply side capacitor 204 via the DC reactor 222. When a current flows and the voltage of the regenerative capacitor 212 falls below the limit voltage, the switching transistor 220 turns off.
By this step-down chopper operation, the regenerative capacitor 212
Voltage of the regenerative capacitor 212 is kept constant.
Magnetic energy that cannot be absorbed by the DC reactor 222
Is temporarily stored in the capacitor 204 to prevent overvoltage of the capacitor 204 on the power supply side.

[0007]

However, in the former drive device 100, two transistors (112a.114a) to (114a.114c) and commutation diodes (116a.118a) to (116c.) Are included in one phase.
Since 118c) is used and the number of elements is large, the device becomes large and complicated, and the number of wiring lines from the phase windings La to Lc of the SR motor to the drive device 100 is a multiple of the phase. Also, there is a problem that the number of connection terminals increases.

In the latter drive device 200, the number of switching elements and commutation diodes is half that of the former drive device, but since the step-down chopper circuit 210 is required,
There is a problem that the circuit configuration becomes complicated. Further, as described above, the SR motor has a characteristic that the output characteristic at the time of high speed rotation is inferior because the inductance of the phase winding is large.

Of course, it is conceivable to improve the characteristics by increasing the DC power supply voltage, but an element having a large withstand voltage or the like is required, and there is a problem that the manufacturing cost becomes high, so that it cannot be easily adopted. Alternatively, when it is difficult to increase the voltage because the DC power source is a battery and there are restrictions on the loading size and weight, as in an electric vehicle, the characteristics can be reduced by reducing the number of windings of the phase winding. It may be improved. However, a larger current is required to generate the same amount of torque, and power −
Since there is a problem that the conversion efficiency of torque deteriorates and there is a limit to the current capacity of the switching element and there is also a limit to increasing the energization amount, it is not possible to improve the high speed rotation characteristic, so it is also adopted It is difficult.

Therefore, the present invention has been made for the purpose of providing a drive device for a variable reluctance motor having a simple and simple structure and excellent high-speed rotation characteristics.

[0011]

SUMMARY OF THE INVENTION The gist of the present invention is a drive unit for a variable reluctance motor that energizes each phase winding of the variable reluctance motor from a DC power supply circuit to drive the variable reluctance motor to rotate. Each of the phase windings is star-connected to each other, and the neutral point of the star connection and the voltage midpoint of the DC power supply circuit are connected together, and each of the star-connected phase windings and the positive electrode of the DC power supply circuit are connected. Alternatively, the variable reluctance motor drive device is provided with an energizing unit that sequentially connects and disconnects the negative electrode and a negative electrode in a predetermined combination to energize the respective phase windings in a predetermined circulation order.

[0012]

According to the apparatus of the present invention constructed as described above, the respective phase windings are star-connected to each other and the neutral point of the star connection is connected to the voltage midpoint of the power supply circuit. Therefore, energization is performed by connecting each of the star windings of the phase windings to the drive device. The energizing means sequentially connects and disconnects the respective phase windings and the positive electrode or the negative electrode of the DC power supply circuit in a predetermined combination. In the energization, the direction from the positive pole of the DC power supply to the neutral point (and the voltage middle point) via the phase winding is the positive direction, while on the other hand, from the neutral point to the voltage middle point and through the phase winding. Since the direction of reaching the negative electrode of the DC power source is the negative direction, the current flowing from the phase winding to the neutral point is the positive direction, and the reverse flow is the negative direction. For example, in the case of a three-phase variable reluctance motor of A phase, B phase, and C phase, the A phase winding is connected to the positive electrode of the DC power supply circuit,
B phase winding to the same negative pole, C phase winding to the same positive pole, A phase winding to the same negative pole, B phase winding to the same positive pole, C phase winding to the same negative pole,
By sequentially connecting and disconnecting, A phase (positive direction) → B phase (negative direction)
→ C phase (positive direction) → A phase (negative direction) → B phase (positive direction) →
Excitation is performed in the cyclic order of C phase (negative direction) → A phase (positive direction). In this way, the variable reluctance motor is rotationally driven.

The variable reluctance motor does not use a permanent magnet for its rotor and attracts the rotor by the electromagnetic force generated by exciting only the stator to rotate the rotor, so that the energization timing is the same. Even if the directions are reversed, the rotational torque is always in the same direction.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is an electric circuit diagram showing a drive unit of a variable reluctance motor to which the present invention is applied, FIG. 2 is an explanatory diagram schematically showing a circuit operation of the drive unit, FIG. 3 is a block diagram of a variable reluctance motor control system, FIG. 4 is an explanatory diagram showing the structure of the variable reluctance motor.

As shown in FIG. 1, a drive unit 10 of a variable reluctance motor (hereinafter referred to as an SR motor) having a three-phase configuration (A phase, B phase and C phase) includes a power supply circuit 13 and a power supply circuit 13. Each phase winding La, Lb, Lc of the SR motor SRM
An energizing circuit 15 for intermittently energizing and deenergizing is configured as a main part and constitutes a part of the SR motor SRM control system.

The power supply circuit 13 includes two rectifying diodes D.
R1 and DR2 and two capacitors C1 and C2 having the same capacity
And a double voltage rectifier circuit configured to rectify a single-phase alternating current AC into a double voltage 2V. The midpoint of connection between the capacitors C1 and C2 connected in series is the midpoint of voltage M, and the single-phase AC AC
Phase winding La, which is connected to one end of
˜Lc is connected to a neutral point N (described later) by a lead line ln.

The energizing circuit 15 has a 6-arm bridge structure and is the same circuit as a so-called inverter. That is, SR
Six transistors (PNP transistors TR1a, TR1) for connecting and disconnecting energization to each phase winding La to Lc of the motor SRM.
1b, TR1c and NPN transistors TR2a, TR2b, T
R2c) and six commutation diodes D1a, D1b, D1 respectively provided to regenerate charges from the phase windings La to Lc.
c, D2a, D2b, D2c. In the energizing circuit 15, commutation diodes D1a to D1c provided on the PNP transistors TR1a to TR1c side and commutation diodes D2a to DNP provided on the NPN transistors TR2a to TR2c side.
D2c is connected in series and the former commutation diode D1a-
The cathode of D1c is connected to the power source bus DCBus (+) on the positive electrode side, and the latter commutation diodes D2a to D2c are connected to the power source bus DCBus (−) on the negative electrode side of the latter.

Further, the connection point between the transistors TR1a and TR2a is provided at one end of the phase winding La with the transistors TR1b and TR1b.
The connection point with 2b is the transistor T at one end of the phase winding Lb.
The connection point of R1c and TR2c is connected to one end of the phase winding Lc by lead lines la, lb, lc, respectively.

As the energizing circuit 15, an inverter made as a general-purpose module may be diverted. In the energizing circuit 15 configured as described above, one of the transistors TR1a to TR2c is turned on in a predetermined circulation order to energize one of the phase windings La to Lc. For example,
TR1a → TR2b → TR1c → TR2a → TR1b → TR2c → T
The transistors TR1a to TR2c are switched in the circulation order of R1a and excited in the circulation order of A phase → B phase → C phase → A phase. The energization period has passed and the transistors TR1a to TR2c are turned off.
When FF is performed, the magnetic energy stored in the phase windings La to Lc is regenerated as electric charge in the capacitor C1 or C2 via the commutation diodes D1a to D1c or D2a to D2c.
The energizing and regenerating paths are PNP transistor TR1a.
.About.TR1c is different from the switching of NPN transistors TR2a to TR2c.

That is, as shown in FIG.
When one of R1a to TR1c (represented by a reference symbol of TR1 in the figure) is turned on, a current flows through a path of a transistor TR1 → the phase winding (represented by a reference symbol L in the figure) → neutral point N, When the transistor TR1 is turned off, the phase winding L → neutral point N → capacitor C2 → commutation diode D2
→ The current i in the loop of the phase winding L (indicated by the dashed line in the figure)
1 flows to charge the capacitor C2. On the other hand, when one of the transistors TR2a to TR2c (indicated by the reference symbol of TR2 in the figure) is turned on, a current flows through the route of the neutral point N → the phase winding L → transistor TR2, and the transistor TR2
When 2 is turned off, the phase winding L → commutation diode D1
→ Capacitor C1 → Neutral point N → Current i2 flows through the loop of the phase winding L (shown by the chain double-dashed line in the figure) to charge the capacitor C1. That is, the transistors TR1a to TR
At the time of energization / interruption by 1c, one of the capacitors C1 and C2 functions as a power supply and the other functions as a regenerative charge storage.

Further, as described above, the NPN transistor T
When switching R2, PNP transistor TR1
The current flows in the opposite direction to that of. However, the SR motor SRM does not use a permanent magnet for the rotor, and attracts the rotor by the electromagnetic force generated by exciting only the stator to rotate the rotor. Therefore, if the energization timing is the same, the rotational torque is always in the same direction even if the energization direction is different.

As shown in FIG. 3, the variable reluctance motor control system (hereinafter, simply referred to as a control system) includes a drive unit 10,
The main control unit 20 and the energization control unit 30 are included. The main controller 20 detects the detection signal S from the magnetic pole sensor (not shown).
S based on the detection signal idet (phase winding current value) from the MP or the current sensor CS, the speed command signal SP from the outside, etc.
The energization cycle and energization period (energization timing) of the R motor SRM are determined. The energization control unit 30 selects a phase to be energized based on the energization timing signals SA, SB, and SC from the main control unit 20 and determines the energization polarity of the phase windings La to Lc, and the forward rotation sequence or the reverse rotation is performed. In order to energize each phase winding La to Lc in sequence, each transistor TR1a is energized.
~ Switching pulse PA, PB, P on the base of TR2c
C, Pa, Pb, Pc are output to output each transistor TR1a.
~ Control switching of TR2c.

Further, the energization control unit 30 executes the well-known chopper control during energization to control the phase winding currents ia, ib, ic to a desired level, and adjust the magnitude of the output torque. Specifically, the duty ratio of chopping is controlled according to the deviation between the target current value and the detected phase winding current value.

Since the structure of each part of the control system is well known, its details are omitted. As shown in FIG. 4, the SR motor SRM operated by the control system is a well-known three-phase motor having a stator ST having a 6-pole structure and a roller RO having a 4- salient pole structure. The stator magnetic poles Pa1 and Pa2 form opposite poles to form an A phase, the stator magnetic poles Pb1 and Pb2 form opposite poles to form a B phase, and the stator magnetic poles Pc1 and Pc2 form opposite poles to form a C phase.
Form a phase. In such a magnetic pole structure, in the section where the rotor salient poles approach the stator magnetic poles (Pa1 · Pa2) to (Pc1 · Pc2), the inductances of the phase windings La to Lc increase and the rotor salient poles become the stator magnetic poles (Pa1).・ Pa2) 〜
When facing (Pc1 · Pc2), the inductance becomes maximum. On the other hand, in the section where the rotor salient poles are separated from the stator magnetic poles Pa1 to Pc2, the inductances of the phase windings La to Lc decrease, and the rotor salient poles become the mechanical angle (60
In the center position (30 degrees, that is, the center of two adjacent magnetic poles), the inductance of the phase windings La to Lc becomes the minimum.

Further, one ends of the phase windings La to Lc of the respective phases A, B and C are star-connected to each other, and the other ends are connected to the terminal block T.
Are connected to the drive unit 10 via lead lines la, lb, lc, and ln. Furthermore, the neutral point N of the star connection
Are connected to the voltage midpoint M of the power supply circuit 13. Therefore, the wire harness between the SR motor SRM and the drive unit 10 has four lead wires la, lb, l from the terminal block T.
Only c and ln.

Next, the SR motor SRM by the drive unit 10
The rotational drive of the above will be described. As shown in FIG. 5, the energization timing of the drive unit 10 is such that the energization control unit 30 sends to the bases of the transistors TR1a to TR2c the switching pulses PA to P whose timings are deviated from each other by an electrical angle of π.
It is determined by inputting C and Pa to Pc.
For example, the transistors TR1a to TR2c are
Switching in the circulation order of 2b → TR1c → TR2a → TR1b → TR2c → TR1a, A phase {phase winding current ia (positive direction)} → B phase {phase winding current ib (negative direction)} → C phase { Phase winding current ic (positive direction)} → A phase {phase winding current ia (negative direction)} → B {phase winding current ib (positive direction)} → C {phase winding current ic (negative direction)} → Bi-directional energization of each phase is performed in the circulation order of the A-phase winding current ia (forward direction)} and the A-phase →
It is excited in the circulation sequence of B phase → C phase → A phase. Furthermore, if current is applied in a region where the inductances of the phase windings La to Lc increase, a positive torque is generated, so the SR motor SR
At the time of driving M, energization is performed in the region where the inductance increases (if energization occurs in the region where the inductance decreases,
Since negative torque is generated, current is applied in the area of reduced inductance during braking).

As described above, since the bidirectional energization of each phase is performed and each phase is excited to drive the SR motor SRM to rotate, the SR motor SRM is operated with smooth rotation with little fluctuation in output torque. .. Then, when the drive unit 10 is energized and de-energized, the two capacitors C1 and C2 of the power supply circuit 13 alternately function as a power supply source or for regenerative charge storage. That is, one capacitor C1 or C2 regenerates the magnetic energy stored in the phase windings La to Lc, and the other capacitor C2 or C1
Since power is supplied to the phase windings La to Lc, magnetic energy is quickly regenerated and a voltage higher than the power supply voltage 2V is applied to the phase windings La to Lc. Therefore, the phase winding current ia
The rising and falling edges of ic become steep.

In the present embodiment, the current is started in the area where the inductance decreases, but this is because the inductance is small and can be ignored. In the area where the inductance changes from decrease to increase, the inductance is small and the current rises sharply. Because.

As described above, in this embodiment, the phase windings La to Lb are star-connected to each other, and the neutral point N of the star connection and the voltage midpoint M of the power supply circuit 13 are connected.
The wire harness between the SR motor SRM and the drive unit 10,
It is possible to use only four lead lines la to lc and ln. Therefore, the drive unit 10 can be downsized and the configuration can be simplified, and the reliability can be increased.

Further, since the energizing circuit 15 has a 6-arm bridge structure, an inverter manufactured as a general-purpose module can be adopted, and the manufacturing of the device is extremely easy. Furthermore, when the drive unit 10 is energized and de-energized,
Since the two capacitors C1 and C2 of the power supply circuit 13 alternately work for power supply or for regenerative charge storage, the phase winding currents ia-ic can be made to rise and fall sharply. Therefore, the output characteristic (rotation speed-torque characteristic) at the time of high speed rotation can be improved.

As described above, in the present embodiment, the two capacitors C1 and C2 are alternately charged and discharged repeatedly, and when the capacitances of the two capacitors are not exactly equal to each other, the capacitance voltage error causes the terminal voltages of the both capacitors to be different from each other. It may expand due to a difference in size. Therefore, stable operation of the SR motor SRM may be realized by detecting the voltage imbalance and changing the energization sequence based on the detection result.

Here, an example of the voltage imbalance detection determination circuit will be described. As shown in column (A) of FIG.
The voltage imbalance detection determination circuit 50 includes a capacitor C1.
Circuit 52 for detecting voltage imbalance between C2 and C2
And a logic circuit 54 including comparators 54a and 54b for comparing and judging the output of the detection circuit 52 with a predetermined threshold value.

The detection circuit 52 includes voltage dividing resistors R1 and R for detecting the terminal voltages VC1 and VC2 of the capacitors C1 and C2.
3 and R2, R4 (where R1 = R2 >> R3 = R4)
And a well-known adder AD. In the adder AD, assuming that the resistance R5 = R6, the output of the adder AD is the sum VC1 + VC2 (hereinafter referred to as the sum voltage) of the voltage across the terminals of the capacitors C1 and C2. However, since the non-inverting terminal (+) is connected to the voltage midpoint M and the neutral point N and the inter-terminal voltage VC2 of the capacitor C2 is detected as a negative potential, the output VAD of the adder AD is [| VC2 |-|
VC1 |] appears, and the output VAD is capacitors C1 and C2.
It is proportional to the magnitude of the voltage imbalance between and.

Comparators 54a and 54b are adders A
The output VAD of D and the positive threshold value R or the output VAD and the negative threshold value S are compared and determined, and the determination signals SJ and SK are output.
These comparison results reflect the magnitude of the potential difference between the capacitors C1 and C2. That is, as shown in the column (B) of the figure, when the output VAD is between the positive threshold value R and the negative threshold value S (R>VAD> S), the sum voltage VC1 + VC2 is also a positive reference value Q. And a negative reference value P. That is, the terminal voltage VC1 of the capacitor C1 and the terminal voltage V2 of the capacitor C2
The voltage imbalance with C2 is small and the comparator 54a
The determination signals of 54 and 54b are both positive (SJ> 0, S
K> 0).

When the output VAD is greater than the positive threshold value R (in the figure, it is in the area shown by the diagonal line rising to the right,
(When VAD >> 0), the sum voltage VC1 + VC2 is
It is smaller than the negative reference value P. That is, the terminal voltage VC2 of the capacitor C2 is considerably higher than the terminal voltage VC1 of the capacitor C1 (VC2 >> VC1), and the comparators 54a and 5a.
The determination signal of 4b is negative and positive (SJ <0, SK>
0).

On the other hand, when the output VAD is smaller than the negative threshold value S (in the area shown by the diagonal line rising to the left in the drawing and VAD << 0), the total voltage VC1 + V
C2 is larger than the positive reference value Q. That is, the capacitor C
The terminal voltage VC1 of 1 is considerably larger than the terminal voltage VC2 of the capacitor C2 (VC1 >> VC2), and the determination signals of the comparators 54a and 54b are positive and negative (SJ> 0, SK).
<0).

The judgment signals SK and SJ are input to the logic circuit 70 provided in the energization control section 30. The logic circuit 70 includes a well-known JK flip-flop FF and a logical product circuit AND, and is included in the energization control unit 30 and energization timing signals SA to SC from the main control unit 20 and determination signals from the comparators 54a and 54b. Based on SJ and SK, a selection signal CH1 or CH2 (both are high) for selecting energization by the PNP transistors TR1a to TR1c or energization by the NPN transistors TR2a to TR2c.
Output). That is, in the energization control unit 30,
When energizing each phase in a predetermined circulation order based on the selection signal CH1 or CH2, PNP transistors TR1a to TR1
Energized by 1c (when CH1 is active), or N
Energization by PN transistors TR2a to TR2c (CH
2 is active).

The figure shows the case of the A phase, but the same applies to the B phase and the C phase. First, when the terminal voltage VC1 of the capacitor C1 and the terminal voltage VC2 of the capacitor C2 are approximate and balanced, the logic circuit 70 alternately outputs the selection signals CH1 and CH2. That is, JK
Since both the J and K inputs of the flip-flop FF are positive, the output (Q and inversion Q) of the JK flip-flop FF is inverted at the rising timing each time the pulse of the energization timing signal SA is input. The product circuit AND alternately outputs the selection signals CH1 and CH2. As a result, the transistors TR1a and TR2a switch in the normal circulation order.

When the terminal voltage VC2 of the capacitor C2 becomes considerably higher than the terminal voltage VC1 of the capacitor C1, the logic circuit 70 outputs only the selection signal CH2. That is, JK
The output of the flip-flop FF is [Q = Low, inversion Q = H
ig], the AND circuit AND selects the selection signal C.
Only H2 is output. As a result, the PNP transistor T
Instead of turning on R1a, the NPN transistor TR2a turns on.
N, the capacitor C2 is discharged and the terminal voltage V
C2 drops and the voltage imbalance is eliminated.

When the terminal voltage VC1 of the capacitor C1 becomes considerably higher than the terminal voltage VC2 of the capacitor C2, the logic circuit 70 outputs only the selection signal CH1. That is, JK
The output of the flip-flop FF is [Q = Hig, inversion Q = L
ow], the AND circuit AND selects the selection signal C
Only H1 is output. As a result, the NPN transistor T
Instead of turning on R2a, TR1a of the PNP transistor turns on, the capacitor C1 is discharged, the terminal voltage VC1 drops, and the voltage imbalance is eliminated.

Further, in the present embodiment, the voltage doubler rectifier circuit is used for the power supply circuit 13, but the power supply circuit may be constituted by a battery in addition to this. For example, as shown in the column (A) of FIG. 7, the power supply circuit 72 is composed of a series circuit of batteries B1 and B2 and a series circuit of capacitors C1 and C2.
The midpoint of connection between the capacitors 1 and B2 is connected to the midpoint of connection of the capacitors C1 and C2 to form a voltage midpoint M. Further, as shown in the column (B) of FIG. 7, the power supply circuit 82 includes one battery BT and two capacitors C1 and C2, and the positive electrode of the battery is connected to the midpoint of connection between the capacitors C1 and C2. The connection point becomes the voltage midpoint M after the capacitor C1 is charged after the SR motor SRM is started.

Even when these batteries B1, B2 and BT are used, the two capacitors C1 and C2 are alternately charged and discharged in the same manner as in the above embodiment. Therefore, the rise and fall of the phase winding currents ia to ic can be made steep to improve the output characteristics (rotation speed-torque characteristics) during high speed rotation.

Therefore, the SR motor can be adopted as the drive motor of the electric vehicle using the battery as the drive power source. Conventionally, since the number of batteries cannot be increased and the output voltage cannot be made high due to the limitation of the loading size and weight of the battery, it is difficult to adopt the SR motor, which has inferior output characteristics at the time of high speed rotation. However, such a problem is overcome in this embodiment.

[0044]

As described above in detail, according to the present invention, the respective phase windings are star-connected to each other, and the neutral point of the star connection and the voltage midpoint of the power supply circuit are connected to each other, and at the same time, the star is connected. Since each of the connected phase windings and the positive electrode or the negative electrode of the DC power supply circuit are sequentially turned on and off in a predetermined combination to energize the respective phase windings in a predetermined circulation order, a variable reluctance and a drive device are provided. The number of lead lines can be reduced.

Therefore, the drive device can be made compact and the structure can be simplified, and the reliability of the device can be increased.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram illustrating a drive unit of a variable reluctance motor according to an embodiment.

FIG. 2 is an operation explanatory diagram of a drive unit.

FIG. 3 is a block diagram of a variable reluctance motor control system.

FIG. 4 is an explanatory diagram of a structure of a variable reluctance motor.

FIG. 5 is an explanatory diagram showing the inductance of the phase winding, the current change characteristic, and the like.

FIG. 6 is an electric circuit diagram of a voltage imbalance detection determination circuit and an explanatory diagram of a voltage imbalance determination operation.

FIG. 7 is an electric circuit diagram showing a drive unit using a power supply circuit having another configuration.

FIG. 8 is an electric circuit diagram showing a drive device of a conventional variable reluctance motor.

[Explanation of symbols]

10 ... Driving part 13 ... Power supply circuit 15 ... Energizing circuit TR1a, TR1b, TR1c ... PNP transistor TR2a, TR2b, TR2c ... NPN transistor C1, C2 ... Capacitor M ... Voltage midpoint N ... Neutral point La, Lb, Lc ... Phase Winding SRM ... Variable reluctance motor

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[Procedure amendment]

[Submission date] February 3, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

[Claims] 1. A drive unit for a variable reluctance motor, which energizes each phase winding of a variable reluctance motor from a DC power supply circuit to rotationally drive the variable reluctance motor, wherein the respective phase windings are star-connected to each other. The neutral point of the star connection and the voltage center of the DC power supply circuit are connected, and each of the star connection phase windings and the positive electrode or the negative electrode of the DC power supply circuit are predetermined. A drive device for a variable reluctance motor, characterized by comprising energizing means for energizing the respective phase windings in a predetermined circulation sequence by intermittently combining them.