JP2000166292A - Switched reluctance motor and its driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress vibration and noise and to improve the efficiency of power in a large load and at a low speed by gently decreasing the excitation current of a phase where the excitation current flows when it is switched. SOLUTION: When a signal being inputted to the base of a chopping transistor Q1 and a rectification transistor Q2 is at high and low levels, the transistors Q1 and Q2 are turned on and off, respectively. When the duty ratio of a pulse width is gradually decreased for each unit angle of an angular detection signal that is detected by a means for detecting the electrical angle of a rotor while the transistor Q2 is kept ON during a period 50, a supply voltage continuously decreases and a current that flows to coil winding L gently decreases, thus reducing the rapid release of force enabling a stator to suck the rotor and hence decreasing the vibration sound of a motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a switch type reluctance motor.

[0002]

2. Description of the Related Art In a switch type reluctance motor, salient poles are provided on both a rotor and a stator, and an exciting current is caused to flow through a winding wound around the salient poles of the stator to excite the salient poles of the stator. The salient poles of the rotor are attracted to the salient poles of the rotor to generate rotational force, and the windings to be excited are sequentially switched by a switch to rotate the rotor at a predetermined speed.

FIG. 11 is a diagram for explaining a method of rotating a three-phase switch type reluctance motor. When the A-phase winding is excited in the positional relationship between the rotor 21 and the stator 20 as shown in FIG. 11A, the salient poles 21a of the rotor 21 near the A-phase are attracted to the A-phase salient poles, The rotor 21 starts rotating counterclockwise. Next, as shown in FIG. 11B, when the B-phase winding is excited in a positional relationship in which the A-phase salient pole and the rotor salient pole 21a are completely opposed, another rotor near the B-phase is excited. The salient pole 21b is attracted to the B-phase salient pole, and the rotor 21 rotates counterclockwise.

Further, as shown in FIG. 11 (c), when the C-phase winding is excited in a positional relationship where the B-phase salient pole and the rotor salient pole 21b are completely opposed, the rotor near the C-phase is excited. The salient pole 21a is drawn to the C-phase salient pole, and the rotor 21 rotates counterclockwise. Thus, the rotor 21 rotates at a predetermined speed by sequentially switching the windings to be excited by the switch.

When the B-phase winding is excited in the positional relationship between the rotor 21 and the stator 20 shown in FIG. 11A, the rotor salient poles 21a are drawn to the B-phase salient poles,
1 rotates clockwise. Then, the A-phase winding is excited according to the positional relationship between the rotor 21 and the stator 20 shown in FIG. 11C, and the rotor 21 and the stator 2 shown in FIG.
When the C-phase winding is excited with a positional relationship of 0, the rotor 21 rotates clockwise. Therefore, regardless of the direction of the exciting current flowing through the winding of the stator 20, the phase of the winding to be energized may be determined based on the positional relationship between the rotor 21 and the stator 20, that is, according to the electrical angle of the rotor 21.

FIG. 12 is a view for explaining the torque of the switch type reluctance motor. As can be seen from FIG.
If an exciting current is applied to the A-phase winding wound around the salient pole 20A from the position where the rotor salient pole 21a starts to face the stator salient pole 20A, the A-phase salient pole 20A of the stator 20 becomes the rotor salient pole 21a. To generate a torque for rotating the rotor 21 counterclockwise in FIG. Then, as shown in FIG. 12B, if an exciting current is applied to the A-phase winding until the A-phase salient pole 20A of the stator 20 and the rotor salient pole 21a completely oppose, a counterclockwise torque is generated. I do.

However, the rotor 21 shown in FIG.
When an exciting current is applied to the A-phase winding to a position where the rotor 21 is further rotated counterclockwise from the position (1), a clockwise torque is generated. As described above, generally, if an exciting current is applied to the winding between the position where the stator salient poles and the rotor salient poles start to be opposed to each other completely, torque in the rotor rotation direction is generated. That is, the torque is always generated in a direction to decrease the magnetic resistance.

Therefore, as shown in FIG. 12A, even if an A-phase stator salient pole 20A and one salient pole of the rotor 21 do not face each other at all and an exciting current flows through the winding of the stator salient pole 20A. A position where no rotational force is generated at the rotor salient pole 21a is defined as an electrical angle of 0 degrees. Then, as shown in FIG. 12B, a position where the stator salient pole 20A and the rotor salient pole 21a completely face each other is defined as an electrical angle of 180 degrees.

In FIG. 12A, the rotor salient poles 21
The rotor position at which the rotor salient pole 21b adjacent to the rotor salient pole a in the counterclockwise direction does not face the stator salient pole 20A at all is an electrical angle
0 degrees. At this time, if a current is applied between the electrical angle of 0 degrees and 180 degrees, a counterclockwise torque is generated, and the electrical angle of 180 degrees
When power is supplied between 360 degrees and 360 degrees, a clockwise torque is generated.

[0010]

FIG. 13 shows the current waveform when the excitation start angle is θ ₀ and the excitation end angle is θc, and the magnitude of the attraction force acting between the stator and the rotor. Thus, in the switch type reluctance motor,
The excitation of the stator phase generates not only a rotational force but also an attractive force on the rotor. The magnitude of the attraction force is proportional to the magnitude of the exciting current, and increases as the position of the rotor salient pole is closer to the position of the stator salient pole.

Attention is now paid to the behavior at the excitation end angle θc, and the electrical angle θq after the excitation is completed at the excitation end angle θc.
In a short period of time, the exciting current suddenly decreases to 0, and a sharp decrease in the attraction force is observed. As a result, the radially opened acceleration is generated in the stator that has been attracted toward the center of the motor. Then, vibration occurs in the stator. This is a problem due to the vibration noise of the motor.

Further, when the motor is running at a low speed and a large load, the exciting current increases as shown in FIG. 14 and a magnetic flux saturation phenomenon occurs in the magnetic path of the motor. It is known that this appears particularly remarkably as the stator salient pole and the rotor salient pole approach the angle θc at which they completely oppose each other. Under such conditions, as shown in FIG.
The exciting current once rises sharply at the exciting end angle θc and then suddenly drops to zero. In this case, the degree of decrease in the attractive force at the excitation end angle θc becomes more remarkable, and the vibration also increases. Also, a large exciting current flows, which is disadvantageous in terms of power consumption efficiency.

FIG. 15 is a waveform diagram showing the relationship between the exciting current supplied to the windings of each phase and the torque generated in the rotor by the switching type reluctance motor shown in FIG. As described above, the excitation current of the phase to which the excitation current was supplied at the excitation end angle θc sharply decreases, and in another phase, the excitation starts and the excitation current increases. For example, at the excitation end angle θc indicated by the dotted line 99, the excitation of the A-phase is suddenly reduced because the excitation of the A-phase is ended, and the excitation current of the B-phase is started and the excitation current starts to increase.

At this time, the torque generated by the A-phase and B-phase excitation currents decreases sharply immediately after the excitation end angle θc, as shown in FIG. It recovers as the B-phase exciting current becomes stable. Thus, a large decrease in the generated torque is seen for each excitation end angle θc. For this reason, a problem such as abnormal noise peculiar to torque fluctuation occurs.

As described above, the conventional switch type reluctance motor has a problem that vibration and noise are generated due to various causes.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a switch type reluctance motor in which vibration and noise are suppressed. It is another object of the present invention to provide a switch type reluctance motor having high power efficiency even at a large load and a low speed.

[0017]

In order to achieve the above object, according to the present invention, a rotor having salient poles, a stator having a plurality of salient poles having windings wound thereon, and An exciting circuit for applying an exciting current to the wire, and a circuit for driving a switch-type reluctance motor in which the rotor rotates by switching the phase for applying the exciting current in a predetermined order, wherein the exciting current is switched when the exciting current is switched. The excitation current of the winding of the phase through which the current has flowed is gradually reduced.

According to such a configuration, the drive circuit of the switch type reluctance motor switches the exciting current by gradually reducing the exciting current flowing through the winding when the exciting current is switched. As a result, when the exciting current is switched, the release of the force by which the stator attracts the rotor becomes gentle, so that the vibration of the stator is reduced.

According to a second aspect of the present invention, in the first aspect, the exciting current is a PWM (Pulse Width Modulati).
on) The excitation current is applied to the winding in response to the signal, and the excitation current is gradually reduced by gradually reducing the duty ratio of PWM when the excitation current is switched.

According to such a configuration, the excitation circuit has a PW
An exciting current is supplied to the winding according to the M signal. When the exciting current is switched, the exciting current supplied to the winding is gradually reduced by gradually reducing the duty ratio of the PWM.

According to a third aspect of the present invention, in the first aspect, the exciting current is detected to match the exciting current with a current command value determined according to the position of the rotor. When switching, the current command value is gradually reduced.

According to such a configuration, since the exciting circuit detects the exciting current by the current detector, the exciting current according to the current command value can be supplied to the winding. Then, at the time of switching the exciting current, the exciting current is gradually reduced by the current command value.

According to a fourth aspect of the present invention, in the second aspect, the duty ratio is gradually reduced before the electrical angle of the rotor reaches the excitation start angle (excitation switching angle) of the next phase. .

When the operation is performed under a large load and a low speed condition, a phenomenon that the exciting current rapidly increases due to the saturation phenomenon of the magnetic flux near the excitation switching angle easily occurs. An abnormal jump of the excitation current is suppressed by gradually reducing the duty ratio before the excitation switching angle.

According to a fifth aspect of the present invention, there is provided a rotor having salient poles, a stator having a plurality of salient poles wound with windings, and an exciting circuit for applying an exciting current to the windings. In a switch-type reluctance motor in which the rotor rotates by switching the phase to which the exciting current is applied in a predetermined order, the exciting circuit simultaneously applies the exciting current to the windings of at least two phases when the exciting current is switched.

According to such a configuration, the drive circuit of the switch-type reluctance motor simultaneously applies the torque that suddenly decreases with the end of the excitation in the phase in which the excitation current is flowing when the excitation current is switched to the winding of another phase. Since the excitation current is compensated by flowing the excitation current, the fluctuation of the torque is reduced as a whole.

According to a sixth aspect of the present invention, there is provided a rotor having salient poles, a stator having an odd number of phases around which windings are wound and having twice the number of phases, and An exciting circuit that applies an exciting current to the wire, and in a switch-type reluctance motor in which the rotor rotates by switching the phase that applies the exciting current in a fixed order, the winding direction of adjacent windings of the stator is The directions are opposite to each other.

According to such a configuration, when the number of phases of the switch type reluctance motor is odd and the number of stator salient poles is twice the number of phases, the winding directions of the stator windings are adjacent. Since the winding directions of the windings are opposite to each other, each winding has the same electromagnetic relationship with the winding wound on the adjacent salient pole. Therefore, the interaction between the phases becomes equal. As a result, torque fluctuations caused by the phases can be reduced.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> Hereinafter, an embodiment of the present invention will be described in detail. FIG. 1 is a circuit diagram of a switch type reluctance motor and a circuit for driving the switch type reluctance motor according to the first embodiment. In the first embodiment, a three-phase single pulse operation, which is the most typical control method for a switch type reluctance motor, is performed. Single pulse operation is PWM as described later.
This is a method of controlling a voltage applied to both ends of a winding of a switch type reluctance motor according to a signal. The mechanical structures of the rotor and the stator are the same as those shown in FIGS.

In FIG. 1, a positive DC power supply is input to an input terminal 1. The input terminal 2 has a ground level GND
Is entered. The capacitor 3 has one pole connected to the input terminal 1 and the other pole connected to the input terminal 2. The first-phase excitation circuit 4, the second-phase excitation circuit 5, and the third-phase excitation circuit 6 have a DC voltage + V smoothed by the capacitor 3.
It operates in response to it.

In the first-phase excitation circuit 4, the NPN-type chopping transistor 7 has a collector connected to the input terminal 1 and an emitter connected to one terminal 32 of the first-phase winding 9. A high-level or low-level signal is input to the base of the transistor 7, and the transistor 7 is on / off controlled.

The NPN rectifier transistor 8 has a collector connected to the other terminal 33 of the winding 9 and an emitter connected to the input terminal 2. A high-level or low-level signal is input to the base of the transistor 8, and the transistor 8 is turned on / off. The rectifier diode 10 has an anode connected to the terminal 33 of the winding 9 and a cathode connected to the input terminal 1. Chopping diode 11
Has an anode connected to the input terminal 2 and a cathode connected to the winding 9
Terminal 32.

In the second phase excitation circuit 5, the NPN type chopping transistor 12 has a collector connected to the input terminal 1 and an emitter connected to one terminal 34 of the second phase winding 14.
It is connected to the. A high-level signal is input to the base of the transistor 12 and the transistor 1
2 is on / off controlled.

The NPN rectifying transistor 13 has a collector connected to the other terminal 35 of the winding 14 and an emitter connected to the input terminal 2. A high-level or low-level signal is input to the base of the transistor 13, and the transistor 13 is on / off controlled. The rectifier diode 15 has an anode connected to the terminal 35 of the winding 14 and a cathode connected to the input terminal 1. The chopping diode 16 has an anode connected to the input terminal 2 and a cathode connected to the terminal 34 of the winding 14.

In the third phase excitation circuit 6, the NPN chopping transistor 17 has a collector connected to the input terminal 1 and an emitter connected to one terminal 36 of the third phase winding 19.
It is connected to the. A high-level or low-level signal is input to the base of the transistor 17 so that the transistor 1
7 is on / off controlled.

The NPN rectifier transistor 18 has a collector connected to the other terminal 37 of the winding 19 and an emitter connected to the input terminal 2. A high-level or low-level signal is input to the base of the transistor 18 so that the transistor 18 is turned on / off. The rectifier diode 30 has an anode connected to the terminal 37 of the winding 19 and a cathode connected to the input terminal 1. The chopping diode 31 has an anode connected to the input terminal 2 and a cathode connected to the terminal 36 of the winding 19. As described above, the internal configurations of the excitation circuits 4, 5, and 6 match.

The microcomputer 38 outputs a 6-bit signal to turn on / off the six transistors 7, 8, 12, 13, 17, and 18, respectively. The driver circuit 39 amplifies the 6-bit signal output from the microcomputer 38 with an amplifier, and supplies the amplified signal to each base of the transistors 7, 8, 12, 13, 17, and 18. Microcomputer 38 and driver circuit 39
Is a circuit for driving a switch type reluctance motor.

Focusing on one phase of the excitation circuits 4, 5, and 6, there are four current conduction modes due to differences in current paths. FIG. 2 shows the four current conduction modes. FIG. 2 focuses on a one-phase excitation circuit, and the one-phase excitation circuit includes a chopping transistor Q1, a winding L, a rectifying transistor Q2, a rectifying diode D1, and a chopping diode D2.

In the first current conduction mode shown in FIG. 2A, both the transistors Q1 and Q2 are on. At this time, as shown by an arrow 40, a current flows from the DC voltage + V to the ground level GND through the transistor Q1, the winding L, and the transistor Q2. In the second current conduction mode shown in FIG. 2B, the transistor Q1 is turned off,
The transistor Q2 is on. At this time, arrow 41
As shown in FIG.
And returns to the winding L again through the diode D2.

In the third current conduction mode shown in FIG. 2C, both the transistors Q1 and Q2 are off. At this time, as indicated by the arrow 42, the current is changed to the ground level G.
ND is regenerated to a DC voltage + V through the diode D2, the winding L, and the diode D1. The fourth part shown in FIG.
In the current conduction mode, the transistor Q1 is on and the transistor Q2 is off. At this time, as shown by the arrow 43, the current flowing through the winding L returns to the winding L again through the diode D1 and the transistor Q1.

Here, the single pulse operation of the conventional switch type reluctance motor will be described. FIG. 3 is a waveform diagram showing a PWM waveform, a supply voltage, and an excitation current by the excitation circuit of each phase (FIG. 2). FIG. 3A shows a signal input to the base of the chopping transistor Q1 (see FIG. 2). When this signal is at a high level, the transistor Q1 is turned on, and when it is at a low level, the transistor Q1 is turned off.

FIG. 3B shows a signal input to the base of the rectifier transistor Q2 (see FIG. 2). When this signal is at a high level, the transistor Q2 turns on, and when it is at a low level, the transistor Q2 turns off. FIG. 3C shows a supply voltage which is artificially applied to both ends of the winding L (see FIG. 2) by turning on / off the transistors Q1 and Q2. FIG. 3D shows an exciting current flowing through the winding L.

When the position of the rotor is between the excitation start angle θ ₀ and the excitation switching angle θc, the transistor Q 1 is chopped with a PWM signal having an appropriate constant pulse width by the signal shown in FIG. Level. Thus, the transistor Q1 is repeatedly turned on and off at a constant cycle, and the transistor Q2 is turned on. Therefore, in this period, the first current conduction mode shown in FIG. 2A and the second current conduction mode shown in FIG. 2B are switched, and an appropriate constant voltage Vs is applied to the winding L. Applied. The exciting current flowing through the winding L starts to increase from the exciting start angle θ ₀ and becomes stable at a constant current value.

After the excitation switching angle θc, both the signal shown in FIG. 3A and the signal shown in FIG. 3B become low level, and both the transistors Q1 and Q2 are turned off. As a result, a third current conduction mode shown in FIG. 2C is established, and the exciting current is regenerated to the DC voltage + V. As a result, FIG.
As shown in (d), when the current flowing through the winding L rapidly attenuates and the rotor position reaches the electrical angle Qq, it becomes zero. Also,
During the period from the electric angle θc to θq, the supply voltage is negative as shown in FIG.

On the other hand, the first embodiment of the present invention operates as shown in FIG. FIG. 4A shows a signal input to the base of the chopping transistor Q1 (see FIG. 2). When this signal is at a high level, the transistor Q1 is turned on, and when it is at a low level, the transistor Q1 is turned off. FIG. 4B shows a signal input to the base of the rectifier transistor Q2 (see FIG. 2). When this signal is at a high level, the transistor Q2 is turned on. When the signal is at a low level, the transistor Q2 is turned on.
2 turns off. FIG. 4C shows transistors Q1 and Q2.
Of the winding L (see FIG. 2) by ON / OFF of the power supply. FIG. 4D shows the winding L
This is the exciting current flowing through.

The operation of the rotor during the period from the excitation start angle θ ₀ to the excitation switching angle θc is the same as that of the conventional switch type reluctance motor shown in FIG. In the present embodiment, after the excitation switching angle θc, both the transistors Q1 and Q2 are not immediately turned off to enter the third current conduction mode as shown in FIG. ), The signal shown in (b) is set to the high level and the transistor Q2 is kept on, and the unit of the angle detection signal detected by the means for detecting the electrical angle of the rotor (not shown) is performed for each unit angle. The duty ratio of the pulse width of the signal shown in FIG. As a result, the supply voltage continuously decreases to a negative value as shown in FIG. 4 (c), and the current flowing through the winding L gradually decreases as shown in FIG. 4 (d).

Then, after the pulse width of the signal shown in FIG. 4A becomes 0, the signal shown in FIG. Control is performed to gradually reduce the pulse width of the signal shown in a) from the duty ratio of 100%. Thereby, the transistor Q
1 repeatedly turns on and off, so that the period during which it is turned on gradually becomes shorter, while the transistor Q2 turns off. Therefore, the switching between the fourth current conduction mode and the third current conduction mode is controlled.

In the period 51, the fourth current conduction mode and the third
Is switched, the current change is smoothly and quickly attenuated. Thus, a phenomenon in which a large amount of the exciting current remains in a region where the current generates a torque opposite to the rotation direction can be avoided. Period 5
In No. 1, the use of the fourth current conduction mode shown in FIG. 2D makes it possible to control the supply voltage to a negative region. Then, the transistors Q1 and Q2 are both turned off, and when the rotor position reaches the electrical angle θq, the exciting current becomes 0, and at this time, the supply voltage also becomes 0.

As described above, in this embodiment, the single-pulse operation as shown in FIG. 4 is performed in each phase, so that the excitation current gradually decreases near the excitation switching angle θc, and the force by which the stator attracts the rotor sharply. Openness is reduced.
Therefore, vibration of the motor is reduced, and vibration noise is reduced. In the embodiment, a three-phase switch-type reluctance motor is used. However, the present invention does not particularly limit the number of phases to three phases.

<Second Embodiment> Next, a second embodiment of the present invention will be described. In the single pulse operation described in the first embodiment, in the case of a large load and a low speed condition, when chopping is performed with a constant pulse width from the excitation start angle θ ₀ to the excitation switching angle θc as shown in FIG.
As shown in FIG. 14, there is a problem that the exciting current rapidly increases near the exciting switching angle θc, resulting in an increase in vibration and an increase in power consumption.

Therefore, in the second embodiment, when the operation is performed under a low load condition with a large load, the pulse width per unit angle is gradually narrowed as the stator and the rotor approach each other before reaching the excitation switching angle θc. The first embodiment further has a control for lowering the supply voltage between the windings. This is shown in FIG. The other parts are the same as in the first embodiment, and a description thereof will be omitted.

From the excitation start angle θ ₀ to the electrical angle θp (however,
In a period 55 until θ ₀ <θp <θc), the transistor Q1 is chopped with a PWM signal having an appropriate constant pulse width by the signal shown in (a), and the signal shown in (b) is set to a high level. As a result, the transistor Q2 is turned on, and the transistor Q1 is repeatedly turned on and off at the cycle of the signal input to the base.

Therefore, in this period 55, the first current conduction mode and the second current conduction mode are repeated. As a result, the supply voltage Vs becomes a constant voltage Vs as shown in (c), but the excitation current increases as shown in (d) under the condition of large load and low-speed operation.

Next, during a period 56 in which the rotor position is between the electric angle θp and the excitation switching angle θc, the signal shown in FIG. For each unit angle of the detected angle detection signal, the duty ratio of the pulse width of the signal shown in FIG. As a result, the supply voltage continuously decreases to a negative value as shown in FIG.
As shown in (1), the exciting current gradually decreases.

Next, when the excitation switching angle θc is reached, the signal shown in FIG. 5B is set to the low level as in the waveform in the period 57, and the pulse width of the signal shown in FIG. Control to gradually decrease from 100% is performed. As a result, while the transistor Q1 is repeatedly turned on and off, the period during which the transistor Q1 is gradually turned on becomes shorter, while the transistor Q2 is turned off. As a result, the exciting current is smoothly and rapidly attenuated as shown in FIG. When the rotor position reaches the electrical angle θq, the supply voltage and the excitation current become zero.

Therefore, at the time of a heavy load and low speed operation, an abnormal jump of the exciting current generated near the excitation switching angle θc as shown in FIG. 14 is suppressed in the present embodiment because the control is performed to attenuate the exciting current. Will be. As a result, the exciting current that has become unnecessarily large at the exciting switching angle θc can be reduced, and the vibration acceleration due to the sudden release of the attractive force can be suppressed. Thereby, the noise of the switch type reluctance motor is reduced. Further, the current consumption of the motor can be reduced, so that the efficiency is improved.

<Third Embodiment> FIG. 6 is a waveform diagram illustrating the operation of a switch type reluctance motor according to a third embodiment. In the single-pulse operation of the conventional switch type reluctance motor, each phase is switched as shown in FIG. 15A, so that the generated torque fluctuates greatly as shown in FIG. However, there are problems such as the generation of abnormal noise peculiar to.

Therefore, in the third embodiment, the chopping pulse width of the phase to which the exciting current is supplied is not changed for several degrees of Δθ from the excitation switching angle θc at which the excitation is started in a new phase in the single pulse operation. Excitation switching angle θ
c Keep the exciting current as before. Thereafter, the exciting current of the original phase is gradually reduced by the PWM control shown in FIG. 4 described in the first embodiment. Thus, in the vicinity of the excitation switching angle θc, two adjacent phases are excited at the same time. The excitation switching angle θc is at a position before the salient pole of the stator and the salient pole of the rotor completely oppose each other.

As shown in FIG. 6B, when the two phases are simultaneously excited, the generated torque for the two phases is the sum of the torques generated when each phase is independently excited. Is known, and the torque generated by the conventional switch type reluctance motor has a smaller fluctuation in the generated torque as compared with FIG. Thus, abnormal noise due to torque fluctuation is reduced, and noise is reduced.

<Fourth Embodiment> Next, a switch type reluctance motor according to a fourth embodiment of the present invention will be described. FIG. 7A shows a three-phase six-pole stator 8 of the present embodiment.
FIG. 7B is a diagram illustrating the direction of winding of the excitation winding of No. 0, and FIG. 7B is a diagram illustrating a comparative example of the present embodiment.

In FIG. 7A, for example, the exciting current supplied by the exciting circuit
The winding is wound so as to flow to 2, 63. Thus, when the exciting current flows in the salient pole 60, the side facing the rotor becomes the N pole. B-phase salient pole 64 adjacent to salient pole 60
In this example, the winding is wound so that the exciting current flows to arrows 65 and 66 when the exciting current flows. Thus, the side of the salient pole 64 facing the rotor becomes the S pole. In the other C-phase salient pole 67 adjacent to the salient pole 60, a winding is wound so that an exciting current flows in arrows 68 and 69. As a result, the side of the salient pole 67 facing the rotor becomes the S pole.

As described above, the winding direction of the salient pole 60 closer to the salient pole 64 shown by the arrow 63 and the salient pole 64 shown by the arrow 65
The winding direction on the side closer to the salient pole 60 is the same.
Further, the winding direction of the salient pole 60 closer to the salient pole 67 as indicated by the arrow 62 is the same as the winding direction of the salient pole 67 closer to the salient pole 60 as indicated by the arrow 69. Such a relationship holds for all salient poles, and the winding directions of adjacent windings of the stator are opposite to each other.

It has been confirmed that when the switched reluctance motor of the present embodiment is excited simultaneously in two phases as in the third embodiment, the exciting current is affected by adjacent mutual inductance. If the winding is wound in the relationship as shown in FIG. 7A, the effect on the A-phase excitation current when the A-phase and the B-phase are simultaneously excited, and the A-phase and the C-phase The effect applied to the A-phase exciting current when excited at the same time comes to coincide. This allows
The fluctuation of the exciting current due to the influence of the mutual inductance can be reduced.

FIG. 7B shows a comparative example for comparison with the embodiment. As shown in FIG. 7B, the A of the stator 81
A winding is wound around the salient pole 70 of the phase so that an exciting current flows through arrows 72 and 73. Thus, when the exciting current flows through the salient pole 70, the side facing the rotor becomes the N pole. A winding is wound around the B-phase salient pole 74 adjacent to the salient pole 70 so that an exciting current flows through arrows 75 and 76. Thus, when the exciting current flows through the salient pole 74, the side facing the rotor becomes the N pole. The winding direction of the salient pole 70 near the salient pole 74 shown by the arrow 73 and the salient pole 7 of the salient pole 74 shown by the arrow 75
The winding direction on the side close to 0 is antiparallel.

On the other hand, another C-phase salient pole 77 adjacent to the salient pole 70 is wound so that an exciting current flows through arrows 78 and 79. Thus, when the exciting current flows through the salient pole 77, the side facing the rotor becomes the S pole. The winding direction of the salient pole 70 on the side closer to the salient pole 77 indicated by the arrow 72 is the same as the winding direction of the salient pole 77 on the side closer to the salient pole 70 as indicated by the arrow 79. As described above, the relationship between the A-phase winding and the winding between the adjacent salient poles is different from that of the stator 80 of the switch-type reluctance motor shown in FIG.

Therefore, the influence of the mutual inductance on the exciting current of the phase A greatly differs between when the phases A and B are excited simultaneously and when the phases C and A are excited simultaneously. As a result, torque fluctuation occurs due to the phase to be excited, which causes the motor to vibrate.

Therefore, as shown in FIG. 7 (a), the variation of the torque can be suppressed by adopting the configuration of the fourth embodiment. This also makes it possible to reduce torque fluctuations and suppress noise. in this way,
If the number of phases is odd and the number of stator salient poles is twice the number of phases, the winding direction of the winding for any salient pole is the direction of winding of the winding wound on the adjacent salient pole. And the direction can be reversed. Thus, no difference in excitation current due to mutual inductance does not appear, which is particularly effective when two phases are excited at the same time as in the third embodiment. In general, the switch-type reluctance motor according to the present embodiment has a characteristic that the torque fluctuation is small and the motor rotates stably regardless of the excitation method.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described. The control method of the switch type reluctance motor according to the fifth embodiment is based on a three-phase current regulator operation. The current regulator operation is a method of controlling a current flowing through a winding of a switch type reluctance motor based on a current command value. FIG. 8 is a circuit block diagram of the switch type reluctance motor when the current regulator is operating.

In FIG. 8, a current controller 84 inputs a current command value 90 and a current value 93 flowing through each phase winding of the switch type reluctance motor 85 so that the current value 93 matches the current command value 90. To output a PWM signal 91. The driver circuit 39 amplifies the PWM signal 91 output from the current control unit 84 and supplies it to the switch type reluctance motor 85.

FIG. 9 is a circuit diagram of the fifth embodiment. In FIG. 9, a positive DC power supply is input to an input terminal 1. A ground level GND is input to the input terminal 2. The capacitor 3 has one pole connected to the input terminal 1,
The other pole is connected to input terminal 2. The first-phase excitation circuit 4, the second-phase excitation circuit 5, and the third-phase excitation circuit 6 operate by receiving the DC voltage + V smoothed by the capacitor 3.

In the first phase excitation circuit 4, the collector of the NPN type chopping transistor 7 is connected to the input terminal 1, and the emitter is connected to one terminal 32 of the first phase winding 9. A high-level or low-level signal is input to the base of the transistor 7, and the transistor 7 is on / off controlled.

The NPN rectifier transistor 8 has a collector connected to the other terminal 33 of the winding 9 and an emitter connected to the input terminal 2 via a current detector 86. A high-level or low-level signal is input to the base of the transistor 8, and the transistor 8 is turned on / off.
The current detector 86 detects the value of the current flowing to the emitter of the transistor 8. The rectifier diode 10 has an anode connected to the terminal 33 of the winding 9 and a cathode connected to the input terminal 1. The chopping diode 11 has an anode connected to the input terminal 2 and a cathode connected to the terminal 32 of the winding 9.

In the second phase excitation circuit 5, the NPN type chopping transistor 12 has a collector connected to the input terminal 1 and an emitter connected to one terminal 34 of the second phase winding 14.
It is connected to the. A high-level signal is input to the base of the transistor 12 and the transistor 1
2 is on / off controlled.

The NPN rectifying transistor 13 has a collector connected to the other terminal 35 of the winding 14 and an emitter connected to the input terminal 2 via the current detector 87.
A high-level or low-level signal is input to the base of the transistor 13, and the transistor 13 is on / off controlled. The current detector 87 detects a value of a current flowing through the emitter of the transistor 13. The rectifier diode 15 has an anode connected to the terminal 35 of the winding 14 and a cathode connected to the input terminal 1. Chopping diode 16
Has an anode connected to the input terminal 2 and a cathode connected to the winding 1
4 terminal 34.

In the third phase excitation circuit 6, the NPN type chopping transistor 17 has a collector connected to the input terminal 1 and an emitter connected to one terminal 36 of the third phase winding 19.
It is connected to the. A high-level or low-level signal is input to the base of the transistor 17 so that the transistor 1
7 is on / off controlled.

The NPN rectifier transistor 18 has a collector connected to the other terminal 37 of the winding 19 and an emitter connected to the input terminal 2 via a current detector 88.
A high-level or low-level signal is input to the base of the transistor 18 so that the transistor 18 is turned on / off. The current detector 88 detects the value of the current flowing through the emitter of the transistor 18.

The anode of the rectifier diode 30 is the winding 19.
And the cathode is connected to the input terminal 1. The chopping diode 31 has an anode connected to the input terminal 2 and a cathode connected to the terminal 36 of the winding 19. As described above, the internal configurations of the excitation circuits 4, 5, and 6 match.

The current values detected by the current detectors 86, 87 and 88 are the current values flowing through the windings of the excited phase as will be described later. The microcomputer 38 includes a current controller 84 (see FIG. 8), and the current detectors 86, 87, and 8
8, the current flowing through the windings 9, 14, 19 of each phase is inputted, and the current flowing through the windings 9, 14, 19 is controlled by controlling the duty ratio of the PWM.
(See FIG. 8).

The microcomputer 38 outputs a 6-bit signal to turn on / off the six transistors 7, 8, 12, 13, 17, 18 respectively. The driver circuit 39 amplifies the 6-bit signal output from the microcomputer 38, and amplifies the transistor 7,
8, 12, 13, 17, and 18 are supplied to each base.

In the excited phase, a PWM signal having a constant duty ratio is input to the base of the chopping transistor Q1 (see FIG. 2) as shown in FIG. As shown in FIG.
A high-level signal is input to the base of. Thereby, as shown in FIG. 3D, the exciting current flowing through the winding L (see FIG. 2) becomes a constant value. The current value of the exciting current is the current detector 86 in the first phase and the current detector 8 in the second phase.
At 7, the current is detected by the current detector 88 in the third phase.

When the duty ratio of the PWM signal shown in FIG. 3A is increased, the period of the first current conduction mode shown in FIG. 2A increases, so that the exciting current increases.
Conversely, when the duty ratio is reduced, the exciting current decreases.
In this way, the current control unit 84 can control the exciting current so as to match the current command value. The current command value 90 is stored in the memory 89 as a value corresponding to the position of the rotor.

FIG. 10 is a waveform chart showing the operation of the fifth embodiment. FIG. 10A shows a current command value for one phase. FIG. 10B shows the exciting current given by the current command value. The position of the rotor from the excitation start angle theta ₀ to excitation switch angle θc current command value as shown in (a) certain exciting current is supplied so is constant.

After the excitation switching angle θc, the current command value is not immediately set to 0, but a period 59 from the excitation switching angle θc to θq is provided to gradually change the current command value to 0 as shown in FIG. Let it. As a result, the current does not suddenly become 0 unlike the exciting current shown in FIG. 2B, so that the force at which the stator attracts the rotor at the exciting switching angle θc is suppressed from being rapidly released. . This allows
Vibration due to sudden release of suction force is reduced, and noise is reduced.

[0084]

As described above, according to the first aspect of the present invention,
According to 3, the excitation current flowing through the winding of the phase in which the excitation current was flowing when the excitation current was switched is changed by changing the duty ratio of the PWM signal by the single pulse operation or changing the current command value by the current regulator operation. Since the excitation current is gradually reduced, the vibration due to the release of the attractive force is reduced in the phase in which the exciting current is flowing. Thereby, the vibration noise of the motor is reduced, and the noise is reduced.

According to the fourth aspect of the present invention, when performing single pulse operation under a large load and a low speed condition, an unnecessary large excitation current at the excitation switching angle is gradually reduced by reducing the PWM duty ratio. Can be reduced. As a result, it is possible to suppress the vibration acceleration due to the sudden release phenomenon of the suction force. Further, since a sudden increase in the exciting current near the excitation switching angle is prevented, power consumption can be reduced and efficiency can be improved.

According to a fifth aspect of the present invention, at least two phases are simultaneously excited at the time of excitation switching, so that the suddenly decreasing torque in the phase where the excitation is completed is compensated for by the simultaneously excited phase to reduce the total torque. Can be suppressed. Thereby, the torque fluctuation is reduced, and the reluctance motor operates stably.

According to the sixth aspect of the present invention, when the number of phases is odd and the number of salient poles of the stator is twice the number of phases, the winding directions of adjacent windings of the stator are opposite to each other. Therefore, the interaction between the windings wound around the adjacent salient poles coincides with each other, and the influence of the mutual inductance in each phase is the same. This prevents fluctuations in the exciting current generated in each phase. Therefore, the motor operates stably without causing torque fluctuation between the phases.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a switch type reluctance motor and a drive circuit thereof according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a current conduction mode in each phase in a single pulse operation of the switch type reluctance motor.

FIG. 3 is a waveform diagram showing a PWM waveform, a supply voltage, and an exciting current during a conventional single pulse operation.

FIG. 4 is a waveform diagram illustrating the operation of the switch type reluctance motor according to the first embodiment of the present invention.

FIG. 5 is a waveform diagram illustrating the operation of the switch-type reluctance motor according to the second embodiment of the present invention.

FIG. 6 is a waveform chart illustrating the operation of the switch type reluctance motor according to the third embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a switch type reluctance motor according to a fourth embodiment of the present invention.

FIG. 8 is a circuit block diagram of a switch type reluctance motor according to a fifth embodiment of the present invention.

FIG. 9 is a circuit diagram of the switch type reluctance motor and its drive circuit.

FIG. 10 is a waveform chart showing the operation of the switch type reluctance motor.

FIG. 11 is a diagram illustrating a method of rotating a switch type reluctance motor.

FIG. 12 is a diagram illustrating torque of the switch type reluctance motor.

FIG. 13 is a diagram showing an excitation current waveform of a conventional switch type reluctance motor and a magnitude of an attractive force acting between a stator and a rotor.

FIG. 14 is a diagram showing an excitation current waveform at low speed and large load torque in a single pulse operation of the switch type reluctance motor.

FIG. 15 is a diagram showing the excitation current of each phase and the generated torque of a conventional switched reluctance motor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 input terminal 2 input terminal 3 capacitor 4 first-phase excitation circuit 5 second-phase excitation circuit 6 third-phase excitation circuit 7 NPN-type chopping transistor 8 NPN-type rectification transistor 9 first-phase winding 10 rectification Diode 11 Chopping diode 12 NPN type chopping transistor 13 NPN type rectifying transistor 14 Second phase winding 15 Rectifying diode 16 Chopping diode 17 NPN type chopping transistor 18 NPN type rectifying transistor 19 Third phase winding 30 Rectification Diode 31 Chopping diode 38 Microcomputer 39 Driver circuit 84 Current control unit 85 Switch type reluctance motor 86, 87, 88 Current detector 90 Current command value 91 PWM signal 93 Each phase winding current value

Claims (6)

[Claims] A rotor having salient poles, a stator having a plurality of salient poles having windings wound thereon, and an exciting circuit for applying an exciting current to the windings, wherein a phase for applying the exciting current is constant. In the circuit for driving a switch-type reluctance motor in which the rotor rotates by switching in the order of, the excitation current of the phase winding in which the excitation current was flowing when the excitation current was switched is gradually reduced. Circuit for driving a switch type reluctance motor. 2. The exciting current provides the exciting current to the winding according to a PWM signal, and gradually reduces the exciting current by gradually reducing a duty ratio of PWM when the exciting current is switched. A circuit for driving a switch-type reluctance motor according to claim 1. 3. The method according to claim 2, wherein the exciting current is detected to match the exciting current with a current command value determined according to a position of the rotor, and the current command value is gradually reduced when the exciting current is switched. Claim 1 characterized by the following:
A circuit for driving the switch type reluctance motor according to 1. 4. The reluctance motor according to claim 2, wherein the duty ratio is gradually reduced before the electrical angle of the rotor reaches an excitation start angle (excitation switching angle) of a next phase. Circuit to drive the. 5. A rotor having salient poles, a stator having a plurality of salient poles having windings wound thereon, and an exciting circuit for applying an exciting current to the windings, wherein a phase for applying the exciting current is constant. A circuit for driving a switch-type reluctance motor in which the rotor rotates by switching in the order of, wherein the excitation current is supplied to the windings of at least two phases when the excitation current is switched. The circuit to drive. 6. A rotor having salient poles, a stator having an odd number of winding-wound phases and twice as many salient poles as the number of phases, and an exciting circuit for applying an exciting current to the windings. In the switch-type reluctance motor in which the rotor rotates by switching the phase giving the exciting current in a predetermined order, the winding directions of adjacent windings of the stator are opposite to each other. Switch type reluctance motor characterized by the following.