JPH11113229A - Switched reluctance motor and its driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a switched reluctance motor by effectively utilizing the windings of the motor. SOLUTION: In a switched reluctance motor, windings 3a-3f between salient poles are respectively wound around the yokes 6a-6f of a stator 2 in the same direction. Each winding 6a-6f is connected with adjacent windings in a loop and power transistors 4a-4c which are connected to a power source, and power transistors 5a-5c which are connected to the ground are respectively provided at the junctions 4a-4c and 5a-5c of the windings 6a-6f. When the transistors 4c and 5c which are at the farthest positions from each other in the loop are turned on, the magnetic fluxes generated between two sets of windings of 3b, 3c, and 3d and 3a, 3f, and 3e flow to a salient pole 2d from a salient pole 2g through salient poles 1d and 1b and rotate a rotor 1 in the direction R. The rotation of the rotor 1 is continuously maintained by changing the phase by successively switching the sets of power transistors. Since magnetic fluxes are always generated in all windings 6a-6f, the numbers of turns of individual windings in salient poles can be reduced and the size of the switched reluctance motor can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switched reluctance motor.

[0002]

2. Description of the Related Art Conventionally, a switched reluctance motor is widely known, for example, as shown in FIG. That is, a stator 102 having an even number of salient poles 101 facing inward and a rotor 104 having an even number of salient poles 103 facing outward are coaxially arranged around a central axis 105. Here, the number of the salient poles 103 of the rotor 104 and the number of the salient poles 101 of the stator 102 are set to an even number which is not a multiple relation with each other. Salient pole 101 of stator 102
Have windings 106 (106A, 106B, 10
6C, 106A ', 106B', and 106C '), and the two windings 106 opposed to each other across the central axis 105.
A and 106A ', 106B and 106B', 106C and 1
06C 'are referred to as phases, respectively.
Three windings are connected in series.

When a motor is driven, a current flows through a winding of one phase to generate a magnetic flux, and attracts a salient pole 103 of a rotor near a stator salient pole of that phase to generate torque. Since the salient poles 103 of the rotor 104 and the salient poles 103 of the stator 102 are set to an even number that does not have a multiple relationship with each other, a certain salient pole, for example, as shown in FIG. 104 salient poles 1
When 03a faces each other, deviation occurs between the other salient poles.
Therefore, if the sequentially shifted salient poles are selected and the phase is energized, the rotor 102 can be continuously attracted to generate torque and rotate the rotor 104. The magnitude of the generated torque is determined according to the relative position between the rotor 104 and the stator 102, the number of turns of the winding 106, and the current supplied thereto.

[0004]

However, in such a conventional switched reluctance motor shown in FIG. 3, for example, the windings 106B, 106B 'and the windings are energized while the phases of the windings 106A and 106A' are energized. 106C,
The phase of 106C 'is de-energized. That is, at this time, the magnetic flux for generating torque is applied to the windings 106A, 10A.
Since it is generated by energizing only the phase of 6A ',
A large ampere-turn (the product of the number of turns and current) is required for the phases of the windings 106A and 106A '.

Since the current value is controlled in relation to heat generation and power consumption, the windings 106A and 106A 'require a large number of turns. Similarly, the other windings 106B, 1
06b 'and the phases of the windings 106C and 106C' also require a large number of turns. As described above, since many phases requiring a large number of windings are required, there is a problem that the shape of the motor becomes large and the cost of the windings becomes high. At the same time, the phase operating at a certain moment is shown in FIG.
In the above example, there is a problem that the configuration is useless in that only one of the three phases is used.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem in the related art, and a switch having a compact size by effectively utilizing windings provided and reducing the number of windings of the windings. The purpose is to provide a reluctance motor.

[0007]

For this reason, a switched reluctance motor according to claim 1 includes a stator having an even number of salient poles and an even number of salient poles which are not in a multiple relation with the number of salient poles of the stator. A rotor having a rotor and a salient-pole winding wound around a yoke portion connecting between salient poles of the stator, and forming two winding sets in which adjacent salient-pole windings are connected in series to form a stator. Are configured to generate a magnetic flux in the salient pole portions of the above.

The above-mentioned stator may be divided along the center line of two salient poles facing each other with the central axis interposed therebetween. In this case, it is preferable that the stator is made of a grain-oriented electrical steel sheet having a characteristic of being easily magnetized in a direction perpendicular to the dividing plane. Each winding between salient poles is wound in the same direction with the same number of turns, and the end of each winding between salient poles is connected to the starting end of the winding between adjacent salient poles to form a loop. Is desirable.

According to a fifth aspect of the present invention, there is provided a motor driving circuit comprising: a first switching means for connecting to one half of a power supply at each of half of the connection portions of the salient-pole windings of the switched reluctance motor. And the other half of the connection portion is provided with second switch means for connecting to the other pole of the power supply, and the first switch means provided on the connection portion located farthest from each other on the loop. A control circuit for simultaneously turning on the second switch means is provided to generate magnetic flux in two salient poles opposed to each other with the central axis interposed therebetween. The half of the connection portion provided with the first switch means may be a half which is continuously adjacent on the loop.

Further, in the motor drive circuit according to the present invention, the first switch means connected to one pole of the power supply and the other pole of the power supply are provided in all connection portions of the winding between the salient poles. And a second switch means connected to the first connection portion provided at one of the connection portions located farthest from each other on the loop.
And a control circuit for simultaneously turning on the switch means and the second switch means provided in the other connection part, and generates magnetic flux in two salient poles opposed to each other with the central axis interposed therebetween.

[0011]

According to the switched reluctance motor of the first aspect, a magnetic flux is generated by a winding set in which a plurality of windings between salient poles wound around a yoke portion are connected in series. For example, in the case of a stator having six salient poles, a magnetic flux is generated in two winding sets in which three salient pole windings wound around a yoke are connected in series three by three, so that individual salient pole windings are formed. The number of turns of the wire is reduced to 1/3 of the conventional one. As a result, the number of windings is reduced and the size of the motor is reduced.

The above-mentioned stator can be easily wound by dividing it along the center line of the two salient poles. In this case, the stator is made of a grain-oriented electrical steel sheet that is easily magnetized in a direction perpendicular to the dividing plane, so that the flow of magnetic flux on the dividing plane is reduced. In addition, by winding all the salient-pole windings in the same direction with the same number of turns, and connecting the salient-pole windings in a loop, the salient-pole windings at any position have the same characteristics. Stable characteristics can be obtained even when the sets are sequentially switched.

According to a fifth aspect of the present invention, in the motor driving circuit, the first circuit provided at the connection portion located farthest from each other on the loop.
By simultaneously turning on the switch means and the second switch means by the control circuit, a magnetic flux is generated in two salient poles opposed to each other with the central axis interposed therebetween. By sequentially switching the switch means to be turned on, the rotor rotates continuously.

According to a seventh aspect of the present invention, in the motor driving circuit, the first circuit provided at the connection portion located farthest from each other on the loop.
Out of the switch means and the second switch means, the first switch means is provided in one connection portion and the second switch means is provided in the other connection portion.
Are simultaneously turned on by the control circuit by the control circuit, a magnetic flux is generated in two salient poles facing each other with the central axis interposed therebetween. When sequentially switching the set (phase) of the connection portions located farthest from each other on the loop, the number of windings between salient poles where current is reversed is suppressed to two.

[0015]

Embodiments of the present invention will be described below with reference to examples. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. The rotor 1 has four outward salient poles 1a to 1a.
The center shaft 1e is supported by a bearing (not shown). The stator 2 has six inward salient poles 2c to 2h.
, The center axis of which is installed coaxially with the center axis 1 e of the rotor 1. Here, the number of the salient poles 1a to 1d of the rotor 1 and the number of the salient poles 2c to 2h of the stator 2 are even numbers which are not in a multiple relation to each other. , And six on the stator side.

The stator 2 has two stator halves 2a, 2a, 2c, 2c, and 2h divided along the center line of the salient pole 2c and the salient pole 2f facing each other across the central axis 1e among the six salient poles 2c to 2h.
b. The stator 2 is formed of a grain-oriented magnetic steel sheet, and has a characteristic that it is easily magnetized in a direction perpendicular to the division surface. Thus, by performing the winding operation on the stator 2 for each half, the winding operation can be easily performed as compared with the case of the annular shape. The stator may be divided into three parts, six parts, and the like, but two divisions are preferable in consideration of the difficulty in passing the magnetic flux at the division part and the degree of improvement in the workability of the winding.

The yoke portions 6a to 6f connecting between adjacent salient poles of the stator 2 are wound with salient pole windings 3a to 3f. That is, between the salient poles 2c and 2d, the inter-salient winding 3a, between the salient poles 2d and 2e, between the salient poles 3e and 2f, between the salient poles 2e and 2f, Salient pole 2f, 2g
A winding 3d between salient poles, a winding 3e between salient poles between salient poles 2g and 2h, a winding 3f between salient poles between salient poles 2h and 2c,
Each is wound by the same number of turns in the same direction.

Next, a drive circuit connected to the above-described salient-pole winding will be described. The ends of the salient pole windings 3a to 3f are connected to the starting ends of the adjacent salient pole windings, respectively.
In FIG. 1 in which the salient poles 2c and 2f are vertically positioned,
Power transistors 4a to 4c are provided between the upper half connection portions 7a to 7c and the power supply Vcc, and power transistors 5a to 5c are provided between the lower half connection portions 8a to 8c and the ground GND, respectively. Have been.

The base terminals of the power transistors 4a to 4c and the power transistors 5a to 5c are connected to a control circuit (not shown), and are turned on in response to drive signals to the base terminals. This allows
According to the combination of the power transistors to be driven, a current in a predetermined direction flows through two sets of windings each including three continuous salient-pole windings, and a magnetic flux is generated along the yoke.

In the state of FIG. 1, when a drive signal is applied to each base terminal of the power transistor 4c and the power transistor 5c to turn them on, the connection portions 7a to 8c
The current flows in the direction of arrow A through the salient pole windings 3b, 3c, and 3d, and the current also flows in the direction of arrow B through the salient pole windings 3a, 3f, and 3e that reach the connection portions 7a to 8c. Flows.
As a result, since the salient pole windings are wound in the same direction, a magnetic flux is generated in the direction of arrow MA along the yoke by the winding set of the salient pole windings 3b, 3c, and 3d. A magnetic flux is generated in the direction of arrow MB along the yoke by the winding set of the inter-pole windings 3a, 3f, 3e.

That is, the magnetic flux generated in the salient-pole winding 3b flows out from the lower end of the salient-pole winding 3b in the figure and passes through the path having the smallest magnetic resistance to the upper end of the salient-pole winding 3b. When the current is passed only to the salient pole winding 3b and the current flows through the salient pole winding 3b, this path becomes the salient pole 2e → the salient pole 1b → the salient pole 2d. However, the magnetic flux is also generated in the salient pole winding 3c. Therefore, the magnetic flux emitted from the lower end of the salient-pole winding 3b is sucked in the direction of the salient-pole winding 3c. Similarly, winding 3c between salient poles
The magnetic flux that has come out of the winding 3
d is sucked in the direction d, and the windings 3b, 3
The magnetic flux is in the MA direction along the yoke around which c and 3d are wound. The same applies to the winding set of the salient interpole windings 3a, 3f, 3e.

The magnetic flux in the direction of arrow MA due to the set of windings between salient poles 3b, 3c and 3d and the magnetic flux in the direction of arrow MB due to the set of windings between windings 3a, 3f and 3e are salient poles 2g. Facing each other. Since the magnetic flux tends to flow to a path having a small magnetic resistance, the magnetic flux generated by the winding set of the salient-pole windings 3b, 3c, and 3d and the magnetic flux generated by the winding set of the salient-pole windings 3a, 3f, and 3e are: It merges and flows like salient pole 2g → salient pole 1d → salient pole 1b → salient pole 2d. Thereby, the salient pole 1 of the rotor 1
The b and 1d are attracted to the salient poles 2d and 2g of the stator, and the rotor 1 generates a torque in the direction of the arrow R.

Next, it is assumed that the rotor 1 is rotated by 30 ° to reach the state shown in FIG. At this time, the control circuit supplies a drive signal to each base terminal of the power transistor 4a and the power transistor 5a to turn them on. As a result, a current flows in the direction of arrow C in the salient-pole windings 3f, 3a, 3b extending from the connection portions 7c to 8a, and similarly, the current flows from the connection portions 7c to 8a.
, A current flows in the direction of arrow D through the salient pole windings 3e, 3d, and 3c. Therefore, the salient pole windings 3f, 3a, 3
A magnetic flux is generated in the direction of arrow MC along the yoke by the winding set b, and a magnetic flux is generated in the direction of arrow MD along the yoke by the winding set of the salient pole windings 3e, 3d, 3c. .

These magnetic fluxes oppose each other at the salient pole 2e and merge to form a salient pole 2e → a salient pole 1c → a salient pole 1a → a salient pole 2h.
Therefore, the salient poles 1a, 1c of the rotor 1
Are attracted to the salient poles 2h and 2e of the stator, respectively.
Torque in the direction of arrow R is continuously generated in the rotor 1.

When the rotor 1 is further rotated by 30 °, the power transistors 4b and 5b are similarly turned on to attract the salient poles 1b and 1d of the rotor 1 to the salient poles 2c and 2f of the stator, respectively. , A torque in the direction of arrow R is generated. When the rotor is further rotated by 30 °, the positional relationship between the salient poles of the rotor and the salient poles of the stator is the same as in FIG. 1, so that the power transistor 4c and the power transistor 5c are turned on. By repeating the above, the power transistors 4a to 4a
By switching between c and 5a to 5c, the rotor rotates continuously.

Since the magnetic flux generated by the winding is determined by the product (ampere turn) of the number of turns and the current, the number of turns of one winding set (here, the number of turns of three windings between salient poles). If the total sum is the same as the number of turns of the winding which has conventionally been wound around one salient pole, the same magnetic flux as in the related art can be obtained.

This embodiment is constructed as described above, and the winding between the salient poles having the same winding direction and the same number of turns is wound around the yoke portion connecting between the salient poles of the stator, and the winding between the adjacent salient poles is formed. Connect a power transistor for energization to the connection part,
All the salient-pole windings are divided into two and connected in series.
A magnetic flux is generated in the salient pole portion of the stator by driving the power transistor so as to form a set of windings.
For example, the number of turns of each salient-pole winding can be greatly reduced, for example, to / 3, so that the cost of the winding and the size of the motor can be easily reduced.

Further, since the stator is divided,
Winding work is easy. Since the directional magnetic steel sheet that is easily magnetized in the direction perpendicular to the division surface is used as the material of the stator, the flow of the magnetic flux on the division surface is reduced, and the characteristics without variation are secured.

In general, the inductance of the winding affects the switching response of the current. In the present embodiment, for example, the power transistors 4a and 5a are turned on when the power transistors 4a and 5a are turned on. The current is reversed when the windings 3f and 3f
c only. When the power transistors 4c and 5c are turned on and the power transistors 4a and 5a are turned on, the current is inverted only when the winding 3 is turned off.
a, 3c, 3d and 3f. In the conventional example, the inductance of the one-phase winding directly affects the switching response of the current. On the other hand, in the embodiment, the inductance is borne by all the windings between the salient poles. The inductance of the wire is small, only affecting the inductance of some of the salient pole windings. Therefore, the responsiveness of the phase switching is good, and the controllability of the torque is also improved.

In the above-described embodiment, half of the connection portions of the adjacent salient-pole windings are provided with a power transistor for conducting to a power supply, and the other half are provided with power transistors for conducting to ground. It is not limited to this.
For example, a power transistor that conducts to the power supply and a power transistor that conducts to the ground according to the drive signal are connected to each connection part, and the connection part at one end turns on the power transistor that conducts to the power supply for each winding between the salient poles. Then, a connection signal at the other end may be supplied with a drive signal so as to turn on a power transistor that conducts to ground, thereby generating a magnetic flux in a required direction. Thereby, at the time of phase switching, the number of windings between salient poles in which the current reverses can always be suppressed to two, and particularly good phase switching response can be stably obtained.

[0031]

As described above, the switched reluctance motor of the present invention has a winding set in which a winding between salient poles is wound around a yoke portion between salient poles of a stator, and the plurality of windings between salient poles are connected in series. Because the magnetic flux is generated by the winding, the number of turns of the winding between the salient poles to generate the same magnetic flux is compared to the conventional method of generating the magnetic flux sequentially only with the winding wound around the salient pole of each phase. This has the effect of reducing the number of windings, reducing the cost and reducing the size of the motor as well as reducing the space for the windings.

Further, by dividing the stator along the center lines of the two salient poles opposed to each other with the central axis interposed therebetween, the shape of the stator is not annular, so that the winding work is facilitated and the workability is improved. In this case, by using a grain-oriented electrical steel sheet with the property of being easily magnetized in the direction perpendicular to the split surface as the stator material, the flow of magnetic flux on the stator split surface is improved, and the characteristics of each salient pole are consistent. Is obtained. Each salient-pole winding is wound in the same direction with the same number of turns, and the end of each salient-pole winding is connected to the starting end of the adjacent salient-pole winding to form a loop. In addition, the salient-pole windings at any position have the same characteristics, and extremely small and stable characteristics such as torque fluctuation can be obtained when the winding sets are sequentially switched and continuously rotated.

The drive circuit for the motor according to the present invention is provided with first switch means for connecting to one pole of the power supply at each half of the connection portion of the winding between salient poles, and each of the other half of the connection portion. A second switch connected to the other pole of the power supply, and simultaneously turning on the first switch and the second switch provided in the connection portion located farthest from each other on the loop, thereby providing a magnetic flux. Therefore, all of the salient-pole windings are used to generate magnetic flux, and the salient-pole windings in which the current is reversed at the time of phase switching are limited to a part. Has the effect of improving the controllability.

Further, a first switch means connected to one pole of the power supply and a second switch means connected to the other pole of the power supply are provided at each connection portion of the winding between the salient poles. In the case where the first switch means provided on one of the connection parts located farthest from each other on the loop and the second switch means provided on the other connection part are simultaneously turned on to generate magnetic flux, Since the number of windings between salient poles where the current is reversed at the time of phase switching is always suppressed to two, the responsiveness of phase switching is further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a state where a rotor has rotated from the state of FIG. 1;

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

Reference Signs List 1 rotor 1a, 1b, 1c, 1d salient pole 1e center axis 2 stator 2a, 2b stator half 2c, 2d, 2e, 2f, 2g, 2h salient pole 3a, 3b, 3c, 3d, 3e, 3f winding between salient poles Lines 4a, 4b, 4c Power transistors (first switch means) 5a, 5b, 5c Power transistors (second switch means) 6a, 6b, 6c, 6d, 6e, 6f Yoke 7a, 7b, 7c, 8a, 8b , 8c connection part

Claims (8)

[Claims] 1. A stator having an even number of salient poles, a rotor having an even number of salient poles not in a multiple relation to the number of salient poles of the stator, and a yoke portion connected between the salient poles of the stator. And two winding sets in which adjacent windings between salient poles are connected in series to generate a magnetic flux at the salient pole portions of the stator. Switched reluctance motor. 2. The switched reluctance motor according to claim 1, wherein said stator is divided along a center line of two salient poles opposed to each other with a central axis interposed therebetween. 3. The switched reluctance motor according to claim 2, wherein the stator is made of a grain-oriented electrical steel sheet having a characteristic of being easily magnetized in a direction perpendicular to the dividing plane. 4. The winding between salient poles is wound in the same direction with the same number of turns, and the end of each winding between salient poles is connected to the starting end of the winding between adjacent salient poles to form a loop. The switched reluctance motor according to claim 1, 2 or 3, which is formed. 5. A first switch means for connecting to one half of a power supply in each of half of the connection portions of the salient pole windings, and the other half of the power supply in each of the other half of the connection portions. And a control circuit for simultaneously turning on the first switch means and the second switch means provided in a connection portion located farthest from each other on the loop, 2 opposed across the central axis
A magnetic flux is generated in the two salient poles.
A motor drive circuit that drives the switched reluctance motor according to any one of the preceding claims. 6. The motor drive circuit according to claim 5, wherein said half of the connection portions provided with said first switch means are continuously adjacent on said loop. 7. A first switch means connected to one pole of a power supply and a second switch means connected to the other pole of the power supply at each connection portion of the winding between the salient poles. A control circuit for simultaneously turning on the first switch means provided on one of the connection parts located farthest from each other on the loop and the second switch means provided on the other connection part; 5. The motor drive circuit for driving a switched reluctance motor according to claim 4, wherein a magnetic flux is generated in two salient poles facing each other across the shaft. 8. The motor drive circuit according to claim 5, wherein each of said first switch means and said second switch means comprises a power transistor.