Reluctance motor, motor system, and control device

Abstract

A reluctance motor 100 is provided with a stator 110 and a rotor 120. The stator 110 has: ns stator salient poles 112; and ns windings L, each of which is concentratedly wound around a corresponding stator salient pole 112. The rotor 120 has np rotor salient poles 122. When k is an arbitrary natural number, and Ns and Np are odd numbers equal to or greater than 3 and relatively prime, ns = 2kNs and np = 2kNp are satisfied. The ns windings form Ns stator coils by connecting 2k windings to each other, the 2k windings being arranged at intervals of Ns, and the stator is configured to be capable of generating a rotating magnetic field synchronized with the rotation of the rotor.

Description

Reluctance motor, motor system, control device

[0001] The present disclosure relates to reluctance motors.

[0002] In recent years, the use of reluctance motors has been expanding. Reluctance motors rotate by utilizing changes in magnetic resistance according to the rotor position, which has the advantage of eliminating the need for permanent magnets and allowing for inexpensive construction.

[0003] There are several types of reluctance motors, such as synchronous reluctance motors (SynRMs) and switched reluctance motors (SRMs).

[0004] Main motors for driving automobiles and motors for home appliances must achieve both high output and high efficiency across a wide range of operating speeds. Recently, a motor that switches the motor type itself has been proposed. This motor operates as a synchronous reluctance motor (SynRM) by switching the polarity of half of the 6N (N is a natural number) windings of a three-phase switched reluctance motor (SRM). This reduces iron loss at low output power (see Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2021-16262

[0006] However, the technology described in Patent Document 1 requires switching the polarity of some of the windings, which requires either providing inverters with twice the number of phases as the original number, or a mechanism for mechanically switching the winding connections, resulting in a problem of increased costs on the motor control side compared to general motors.

[0007] The present disclosure has been made in light of this situation, and one exemplary purpose of an embodiment thereof is to provide a reluctance motor that can be operated like a synchronous reluctance motor or like a switched reluctance motor without changing the connections of the stator coils (stator windings).

[0008] An aspect of the present disclosure relates to a reluctance motor. ｓ n salient stator poles and n concentrated windings on the corresponding salient stator poles ｓ a stator having n windings; ｐ and a rotor having salient poles, where k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ Satisfies. ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ The stator is configured to generate a rotating magnetic field synchronized with the rotation of the rotor.

[0009] An aspect of the present disclosure relates to a reluctance motor. ｓ n rotor salient poles and n concentrated windings on the corresponding rotor salient poles ｓ a rotor having n windings; ｐ and a stator having salient stator poles, where k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ Satisfies. ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ The rotor is configured to generate a static magnetic field relative to the stator regardless of its position.

[0010] Any combination of the above components or conversion of the expressions of the present disclosure between methods, devices, etc. are also valid aspects of the present invention. Furthermore, the description in this section (Means for Solving the Problems) does not explain all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention.

[0011] According to certain aspects of the present disclosure, a reluctance motor can be operated like a synchronous reluctance motor or a switched reluctance motor without changing the connections of the coils (windings) of the reluctance motor, and the configuration of a control device for driving the reluctance motor can be simplified.

[0012] 10 is a cross-sectional view of a reluctance motor according to an embodiment. FIG. 11 is an equivalent circuit diagram of a reluctance motor according to a first example. FIG. 12 is a block diagram of a motor system including the reluctance motor of FIG. 2. FIG. 13 is a waveform diagram showing a drive current in SynRM mode. FIG. 14 is a waveform diagram showing a drive current in SRM mode. FIG. 15 is a diagram showing magnetic fluxes generated by the MRM and DRM in SynRM mode. FIG. 16 is a diagram showing magnetic fluxes generated by the MRM and DRM in SRM mode. FIG. 17 is an equivalent circuit diagram of a reluctance motor according to a second example. FIG. 18 is a block diagram of a motor system including the reluctance motor of FIG. 11. FIG. 15 is a diagram showing the output and efficiency of the MRM and DRM in SynRM mode. FIG. 16 is a diagram showing the output and efficiency of the MRM and DRM in SRM mode. FIG. 17 is a diagram showing the efficiency and output of the MRM in SynRM mode and SRM mode. FIG. 18 is a diagram showing the relationship between torque and efficiency of the MRM at a rotation speed of 7500 RRM. FIG. 19 is a cross-sectional view of a reluctance motor according to a modified example.

[0013] (Summary of the Embodiments) A summary of some exemplary embodiments of the present disclosure will be provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows, and is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may be used to refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0014] The reluctance motor according to one embodiment has n ｓ n stator salient poles and n concentrated windings on the corresponding salient poles ｓ a stator having n windings; ｐ and a rotor having salient poles, where k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ Satisfies. ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ The stator is configured to generate a rotating magnetic field synchronized with the rotation of the rotor.

[0015] This configuration allows the reluctance motor to operate like a synchronous reluctance motor or a switched reluctance motor without changing the connection of the stator coil (stator windings) of the reluctance motor. Also, the configuration of the control device that drives the reluctance motor can be simplified.

[0016] The reluctance motor according to one embodiment has n ｓ n rotor salient poles and n concentrated windings on the corresponding rotor salient poles ｓa rotor having n windings; ｐ and a stator having salient stator poles, where k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ Satisfies. ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ The rotor is configured to generate a static magnetic field relative to the stator regardless of its position.

[0017] This configuration allows the reluctance motor to operate like a synchronous reluctance motor or a switched reluctance motor without changing the connection of the rotor coil (rotor windings) of the reluctance motor. Also, the configuration of the control device that drives the reluctance motor can be simplified.

[0018] In one embodiment, N ｓ The coils may be star-connected, with wiring drawn out from one end of each coil and the neutral point. A motor system according to one embodiment includes this reluctance motor and an N-type reluctance motor connected to the reluctance motor. ｓ and a controller including a phase inverter circuit.

[0019] In one embodiment, N ｓ Wires may be drawn out from both ends of the coils. ｓ The control device may include a control circuit including H-bridge circuits, each H-bridge circuit connected to a corresponding coil of the reluctance motor.

[0020] A control device according to one embodiment drives any of the reluctance motors described above. The drive device includes a switching circuit connected to the reluctance motor and a controller that controls the switching circuit. The controller is switchable between a first mode in which a current without a DC offset is supplied to the windings to generate a rotating magnetic field synchronized with rotor rotation, and a second mode in which a current with a DC offset is supplied to the windings to generate a non-rotating magnetic field.

[0021] (Embodiments) The present disclosure will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be assigned the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0022] 1 is a cross-sectional view of a reluctance motor 100 according to an embodiment. The reluctance motor 100 includes a stator 110 and a rotor 120. The reluctance motor 100 has a doubly salient pole structure, and the stator 110 has n ｓ stator salient poles 112 and n ｓ The rotor has windings (hereinafter also simply referred to as windings) L.

[0023] The rotor 120 is ｐ The rotor has salient poles 122.

[0024] A switched reluctance motor utilizes the fluctuation of self-inductance, so each phase requires a pair of windings with opposite polarities. ｓ The minimum number of stator salient poles in the configuration is 2 × N ｓ When generalized using an arbitrary natural number k, the number of stator salient poles 112 n ｓ is 2k×N ｓ This becomes:

[0025] Correspondingly, in order to form a magnetic circuit by combining with the stator salient poles 112, the rotor salient poles 122 also need to be paired one to one. The minimum number of rotor salient poles 122 is n ｐ is 2 × Nｐ and when generalized, it is 2k×N ｐ It becomes n ｓ = 2 kN ｓ n ｐ = 2 kN ｐ

[0026] In order to generate torque continuously regardless of the position of the rotor salient poles, ｓ ≠N ｐ The relationship between N ｓ :N ｐ is the number n of the stator salient poles 112 ｓ and the number n of rotor salient poles 122 ｐ In this embodiment, N ｓ and N ｐ are odd numbers greater than or equal to 3 that are mutually prime.

[0027] In the example of FIG. 1, k=1, n ｓ = 10,n ｐ = 6, and N ｓ :N ｐ = 5:3. ｓ Each of the windings L1 to L10 is concentratedly wound around the corresponding stator salient pole 112. The polarities of the windings L are alternately repeated as N, S, N, S, etc. 2k windings arranged at equal intervals are connected to each other to form one stator coil. The stator 110 has n ｓ / (2 ｋ ) = N ｓ The rotor has stator coils Ls.

[0028] In this example, k=1, so the two windings L ｊ (j=1, 2..., N ｓ ) and N ｓ L located at a distance of ｊ＋Ｎｓ A pair of these is connected in series to form one stator coil.

[0029] The above is the configuration of reluctance motor 100. As will be explained below, this reluctance motor 100 can operate like a synchronous reluctance motor or like a switched reluctance motor without changing the connection of the windings (stator coils). For this reason, this reluctance motor 100 will be referred to as a multi-mode reluctance motor (MRM) hereinafter.

[0030] As the degree of freedom in the controlled current increases, the number of voltage sources required for the circuit topology also increases. To reduce the overall cost of the motor system, it is important to minimize the number of inverter legs and minimize the electrical packaging cost, and therefore the mechanical design of the reluctance motor 100 becomes important.

[0031] In a conventional switched reluctance motor (SRM), the number of stator salient poles is n ｓ and the number of rotor salient poles n ｐ Ratio of N ｓ :N ｐ In the case of a three-phase system, the ratio is generally 3:2, and in the case of a five-phase system, the ratio is generally 5:4. ｓ and N ｐ is an odd number greater than or equal to 3.

[0032] N ｓ and N ｐ If N are not relatively prime, the periodicity corresponding to the factors is included in the mechanical design, and there is room to reduce the degree of freedom of the controlled current. ｓ and N ｐ are relatively prime, the degree of freedom of the current is minimized. The reluctance motor 100 according to the embodiment satisfies this condition.

[0033] N ｓ When is an odd number other than 1, in other words, an odd number equal to or greater than 3, magnetic anti-periodicity is provided by arranging windings adjacent to each other with different phases and different polarities. Considering the principles of switched reluctance motors, this is a minimal mechanical design. The reluctance motor 100 according to the embodiment satisfies this condition.

[0034] Furthermore, N ｐ When is an odd number other than 1, in other words, an odd number equal to or greater than 3, the excitation direction of the salient rotor poles is always constant by switching the current direction of the windings each time the salient rotor poles pass by. By imparting magnetic anti-periodicity to the rotor in correspondence with the stator imparted magnetic anti-periodicity, the motor can operate in a manner that can be interpreted as a synchronous reluctance motor. The reluctance motor 100 according to the embodiment satisfies this condition.

[0035] In this way, in the reluctance motor according to the embodiment, by considering the magnetic anti-periodicity from a geometrical perspective with respect to the mechanical structure expressed by the number of stator salient poles and the number of rotor salient poles, it is possible to reduce the electrical implementation costs of the drive device in the circuit topology.

[0036] Also, N ｓ By setting is an odd number equal to or greater than 3, the operating conditions for a switched reluctance motor and those for a synchronous reluctance motor can be switched by changing the control method of the inverter circuit without changing the connections of the stator coils.

[0037] The reluctance motor 100 is ｓ There are two forms (embodiment 1 and embodiment 2) for connecting the stator coils.

[0038] (First embodiment) Fig. 2 is an equivalent circuit diagram of a reluctance motor 100A according to a first embodiment. ｓ As described above, each stator coil Ls includes 2k windings L. In the first embodiment, five (N ｓ The stator coils Ls (number of coils) are star-connected. ｓ Driving wires are drawn from one end of each of the stator coils Ls and the neutral point com of the star connection, forming a 5-phase, 6-pole, 10-slot motor. ｓ For convenience, the five phases are denoted as U, V, W, X, and Y phases.

[0039] Next, the driving of the reluctance motor 100A will be described.

[0040] Fig. 3 is a block diagram of a motor system 2A including the reluctance motor 100A of Fig. 2. The motor system 2A includes a control device 200A that controls the reluctance motor 100A. The control device 200A includes a switching circuit 220A and a controller 230, and is connected to a power supply 210.

[0041] The power supply 210 generates a positive voltage +Vdc and a negative voltage −Vdc to the switching circuit 220A with the potential of the neutral point com of the reluctance motor 100A as a reference.

[0042] The switching circuit 220A is ｓ The controller 230 controls the switching circuit 220A to control the current i flowing through the five-phase stator coil Ls of the reluctance motor 100A. ｕ , i ｖ , i ｗ , i ｘ , i ｙ Control.

[0043] The controller 230 is capable of switching between a mode in which the reluctance motor 100A operates as a synchronous reluctance motor (referred to as SynRM mode) and a mode in which the reluctance motor 100A operates as a switched reluctance motor (referred to as SRM mode).

[0044] For the explanation of SynRM mode and SRM mode control, ｓ The stator coils are numbered 0, 1, ..., N ｓ -1 is added to this number, and the physical position m ｐ It is called.

[0045] SynRM mode In SynRM mode, the controller 230 controls the switching circuit 220A so that a current without a DC offset is supplied to the winding (stator coil Ls), thereby causing the stator 110 to generate a rotating magnetic field synchronized with the rotation of the rotor 120.

[0046] m ｐ The magnetic flux generated by the stator coil is Φ ｐ (θｅ , β ｅ , m ｐ ) = Φ cos(θ ｅ -m ｐ ・N ｐ π / N ｓ +β ｅ ) θ ｅ is the electrical angle, β ｅ is the electrical phase angle.

[0047] m ｓ is called the electrical position, and ｓ In order for the reluctance motor 100 to operate as a synchronous reluctance motor, m ｓ The magnetic flux generated by the stator coil is Φ ｓ (θ ｅ , β ｅ , m ｓ ) = Φ cos(θ ｅ -m ｓ 2π / N ｓ +β ｅ ) must be.

[0048] Therefore, in SynRM mode, m ｐ and m ｓ The correspondence relationship that must be satisfied by N is as follows: ｐ m ｐ ≡2m ｓ (mod N ｓ ) N ｓ = 5, N ｐ When m = 3, ｐ = 0: m ｓ = 0 m ｐ = 1: m ｓ = 4 m ｐ = 2: m ｓ = 3 m ｐ = 3: m ｓ = 2 m ｐ = 4: m ｓ = 1. In other words, the electrical position m of each stator coil ｓ is the physical position m ｐ It is sufficient to set it in the opposite direction.

[0049] FIG. 4 shows the drive current i in SynRM mode. ｕ , i ｖ , iｗ , i ｘ , i ｙ FIG.

[0050] SRM Mode In SRM mode, the controller 230 controls the switching circuit 220A so that a current having a DC offset is supplied to the winding (stator coil Ls), thereby causing the stator 110 to generate a non-rotating magnetic field.

[0051] The average value and amplitude of the rotor permeance are P ｒ＿ｄｃ and P ｒ＿ａｃ When defined as θ ｅ m in ｐ The rotor permeance near the stator coil is P ｐ (θ ｅ , m ｐ ) = P ｒ＿ｄｃ +P ｒ＿ａｃ cos(2θ ｅ -2 m ｐ ・N ｐ π / N ｓ )

[0052] On the other hand, the excitation order in SRM mode generally coincides with the order in which the rotor permeance is maximized. ｓ The rotor permeance near the stator coil is P ｓ (θ ｅ , m ｓ ) = P ｒ＿ｄｃ +P ｒ＿ａｃ cos(2θ ｅ -m ｓ 2π / N ｓ ) is defined as:

[0053] Therefore, in SRM mode, m ｐ and m ｓ The correspondence relationship that must be satisfied by N is as follows: ｐ m ｐ ≡m ｓ (mod N ｓ ) N ｓ = 5, N ｐ When m = 3, ｐ = 0: m ｓ = 0 m ｐ = 1: m ｓ= 3 m ｐ = 2: m ｓ = 1 m ｐ = 3: m ｓ = 4 m ｐ = 4: m ｓ =2.

[0054] FIG. 5 shows the driving current i in the SRM mode. ｕ , i ｖ , i ｗ , i ｘ , i ｙ FIG.

[0055] The above is the configuration of the motor system 2A.

[0056] The multi-mode reluctance motor (MRM) according to the embodiment and a conventional dual-mode reluctance motor (DRM) have in common the point of switching between two modes, but the magnetic flux generated in each mode is completely different, and they should not be considered the same.

[0057] FIG. 6 is a diagram showing magnetic fluxes generated by the MRM and the DRM in the SynRM mode.

[0058] FIG. 7 is a diagram showing magnetic fluxes generated by the MRM and DRM in the SRM mode.

[0059] (Embodiment 2) Fig. 8 is an equivalent circuit diagram of a reluctance motor 100B according to embodiment 2. The cross-sectional structure of this reluctance motor 100B is the same as that shown in Fig. 1, but ｓ The connections of the five stator coils Ls differ from those in the equivalent circuit diagram of Fig. 2. In the second embodiment, the five stator coils Ls are not connected, and driving terminals are provided at both ends. There is also no neutral point.

[0060] Fig. 9 is a block diagram of a motor system 2B including the reluctance motor 100B of Fig. 8. The motor system 2B includes a control device 200B that controls the reluctance motor 100B. The control device 200B includes a switching circuit 220B and a controller 230. The switching circuit 220B includes an N ｓThe reluctance motor 100B includes five H-bridge (full-bridge) circuits 240. In this example, since the reluctance motor 100B has five phases, five H-bridge circuits 240_1 to 240_5 are provided.

[0061] Each H-bridge circuit 240_i (i=1, 2, . . . N ｓ ) includes four switches, receives a potential difference Vdc from a connected power supply, and controls the voltage across the corresponding stator coil Ls to supply a coil current to the corresponding stator coil Lsi.

[0062] The controller 230 is capable of switching between a mode in which the reluctance motor 100B operates as a switched reluctance motor (referred to as an SRM mode) and a mode in which the reluctance motor 100B operates as a synchronous reluctance motor (referred to as a SynRM mode).

[0063] Next, we will explain the results of a comparison between the MRM and DRM using a simulator. In the simulation, the inverter circuit outputs were made uniform and the efficiency and output of the motors were compared.

[0064] DRM: Full bridge 6-phase bridge circuit output 650V x 69Arms x 6Unit = 269100VA

[0065] MRM: Full bridge 5-phase bridge circuit output 650V x 82.8Arms x 5Unit = 269100VA

[0066] 10 is a diagram showing the output and efficiency of MRM and DRM in SynRM mode. Compared to DRM, MRM shows improvements in both output and efficiency over a wide speed range.

[0067] FIG. 11 shows the output and efficiency of the MRM and DRM in SRM mode. Focusing on efficiency, the MRM and DRM are almost identical in SRM mode, but the MRM is slightly inferior in the low rotation speed range. Focusing on output, the MRM is inferior to the DRM over a wide speed range. However, in a reluctance motor, there is a trade-off between the characteristics of the SRM mode and the MRM mode, depending on the mechanical design, specifically the thickness of the yoke, and other parameters. Therefore, by optimizing the mechanical design, it is possible to improve the output of the MRM in SRM mode to a level comparable to that of the DRM, while maintaining the advantages in SynRM mode.

[0068] Next, switching of the operation mode of the MRM will be described.

[0069] Figure 12 shows the efficiency and output of the MRM in SynRM mode and SRM mode. In the high rotation range, high output can be obtained by selecting SRM mode. On the other hand, in the low rotation range, high efficiency and high output can be obtained by selecting SynRM mode.

[0070] Figure 13 shows the relationship between torque and efficiency of an MRM at a rotation speed of 7,500 RPM. In SynRM mode, maximum torque is limited, but the highest efficiency reaches 96.3%. In SRM mode, maximum torque is superior, but efficiency is inferior in the coexistence region. In other words, switching between high-efficiency mode and high-output mode is a very useful technique for MRM.

[0071] Finally, a modification of the reluctance motor 100 will be described.

[0072] (Modification 1) Fig. 14 is a cross-sectional view of a reluctance motor 100a according to Modification 1. In this modification, n ｓ = 20, n ｐ = 12, k = 2, N ｓ :N ｐ =5:3.

[0073] Twenty windings L1 to L20 are provided for the twenty stator salient poles 112. j=1, 2, . . . N ｓThen, 2k = 4 windings L are arranged at equal intervals. ｊ , L ｊ＋５ , L ｊ＋１０ , L ｊ＋１５ are connected to form the stator coil Lsj.

[0074] (Modification 2) k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ N satisfies ｓ and N ｐ Combination of (N ｓ , N ｐ ) is not limited to (5, 3). ｓ , N ｐ ) is (N ｓ , N ｐ ) = (3,5), (5,7), (7,3), (7,5), (7,9), etc. are valid.

[0075] (Modification 3) The reluctance motor 100 has the windings L on the stator 110, but may have the windings L on the rotor 120. In this case, the rotor and stator in the above description may be replaced with each other, and the following configuration may be obtained. ｓ n rotor salient poles and n concentrated windings on the corresponding rotor salient poles ｓ The stator has n rotor windings. ｐ The number of stator salient poles is N. ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ Satisfies. ｓ The rotor windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ Form rotor coils.

[0076] (Variation 4) In a single application, the reluctance motor 100 may be used by dynamically and adaptively switching modes according to the rotation speed, but is not limited to this. If a certain application requires high performance only in a specific rotation range, the control device does not need to be able to switch between the SynRM mode and the SRM mode, and may be configured to operate in a single mode suitable for a specific rotation speed.

[0077] The present disclosure has been described using specific terms based on the embodiments, but the embodiments merely illustrate the principles and applications of the present disclosure, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the concept of the present invention defined in the claims.

[0078] The present disclosure relates to reluctance motors.

[0079] 100 Reluctance motor 110 Stator 112 Stator salient pole L Winding 120 Rotor 122 Rotor salient pole

Claims

1. n ｓ n salient stator poles and n concentrated windings on the corresponding salient stator poles ｓ a stator having n windings; ｐ a rotor having rotor salient poles, and k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ and the n ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ a stator configured to generate a rotating magnetic field synchronized with the rotation of the rotor; 2. n ｓ n rotor salient poles and n concentrated windings on the corresponding rotor salient poles ｓ a rotor having n windings; ｐ a stator having salient stator poles, and k is an arbitrary natural number, N ｓ and N ｐ When n is an odd number greater than or equal to 3 and is relatively prime, ｓ = 2 kN ｓ n ｐ = 2 kN ｐ and the n ｓ The windings are arranged with alternating polarities, and N ｓ By connecting 2k windings arranged at intervals of N ｓ 1. A reluctance motor comprising: a rotor having a plurality of coils, the rotor being configured to generate a static magnetic field relative to the stator regardless of its position.

3. The above N ｓ 3. A reluctance motor according to claim 1, wherein the coils are star-connected, and wires are drawn out from one end and a neutral point of each coil.

4. The above N ｓ 3. A reluctance motor according to claim 1, wherein wiring is drawn out from both ends of each coil.

5. A reluctance motor according to claim 3, and a N-type reluctance motor connected to said reluctance motor. ｓ A motor system comprising: a control device including a phase inverter circuit.

6. A reluctance motor according to claim 4; ｓ a control device including H-bridge circuits, each H-bridge circuit connected to a corresponding stator coil of the reluctance motor; 7. N ｓ :N ｐ 3. A reluctance motor according to claim 1, wherein the ratio of the torque to torque is 5:

3.

8. A control device for driving a reluctance motor according to claim 1 or 2, comprising: a switching circuit connected to said reluctance motor; and a controller for controlling said switching circuit, said controller being switchable between a first mode in which a current having no DC offset is supplied to said windings to generate a rotating magnetic field synchronized with the rotation of said rotor, and a second mode in which a current having said DC offset is supplied to said windings to generate a non-rotating magnetic field.

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