JP2010166761A - Switched reluctance motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight switched reluctance motor with few torque ripples, which is easily manufactured. <P>SOLUTION: A stator core includes a plurality of soft magnetic stator segments 3 extended in the axial direction which are disposed at a pitch of the electrical angle 2π in the circumferential direction. Each of the stator segments 3 includes stator magnetic poles 31 to 34 disposed in the axial direction while pinching slots. A rotor core includes a plurality of rotor segment groups composed of a plurality of soft magnetic rotor segments 7U, 7V, 7W extended in the axial direction in such a way that they are disposed at a pitch of the electric angle 2π in the circumferential direction. The stator magnetic poles 31, 32 are magnetically short-circuited by the rotor segment 7U, the stator magnetic poles 32, 33 are magnetically short-circuited by the rotor segment 7V, and the stator magnetic poles 33, 34 are magnetically short-circuited by the rotor segment 7W. DC coils 40A, 40B, 40C and AC coils 4A, 4B, 4C, each of which is made of a ring coil, penetrate the slots between the respective magnetic poles 31 to 34 in the circumferential direction, respectively and separately. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a switched reluctance motor and its drive circuit.

(Conventional axial direction RM)
A reluctance motor (RM) that utilizes a change in the magnetic resistance (reluctance) of a soft magnetic rotor core does not use an expensive permanent magnet, and thus has an advantage of high strength and reduced manufacturing cost. Further, compared with a normal synchronous motor having a permanent magnet type rotor, mechanical support of the permanent magnet is not required, so that high speed rotation is possible, and the problem of back electromotive force during high speed rotation does not occur. These advantages are preferable as a variable-speed high-speed rotation motor such as a motor-assisted turbocharger or an in-wheel motor. As the RM, a synchronous reluctance motor (SynRM), a switched reluctance motor (SRM), and a VR type stepping motor are known.

RM (axial direction RM) in which magnetic flux flows in the axial direction is known. For example, a VR type stepping motor has a ring coil and a claw tooth, and a magnetic flux flows in an axial direction in a stator core (claw pole core).
Patent Documents 1 to 5 below disclose SRM or VR type stepping motors in which a plurality of horseshoe-shaped (C-shaped) cores around which a stator coil is concentrated are distributed in the circumferential direction.
Patent Document 1 (Fujitani) proposes a VR stepping motor having a stator core composed of a C-shaped core and a cylindrical rotor core. This motor has a number of stator-rotor pairs equal to the number of phases arranged in tandem in the axial direction. The stator coil is concentratedly wound on a yoke that extends in the axial direction as part of each horseshoe-shaped stator core. The C-shaped core has magnetic poles (polar teeth) that are adjacent to each other in the axial direction and have opposite polarities.

Patent Document 2 (Kunihiro) proposes an axial gap SRM in which a C-shaped core is disposed radially outside a disk-shaped rotor core. The stator magnetic pole and the rotor magnetic pole face each other in the axial direction.
Patent Document 3 (Takahashi) proposes a radial gap VR type motor in which a plurality of C-shaped cores forming a stator core are distributed in the circumferential direction, and a plurality of C-shaped cores forming a rotor core are distributed in the circumferential direction. . The C-shaped core is configured by laminating electromagnetic steel plates bent into a C shape.

Patent Document 4 (Takano) has a plurality of C-shaped cores in which a stator core is positioned on one end side in the axial direction of a disk-shaped rotor core and arranged in the circumferential direction, and a plurality of C-shaped cores in which the rotor core is arranged in the circumferential direction. An axial gap VR type motor having a core is proposed. The stator magnetic pole and the rotor magnetic pole face each other in the axial direction. Two stator magnetic poles having opposite polarities of the horseshoe-shaped core are arranged in the radial direction. The spatial phase between the horseshoe-shaped core of the stator and the rotor magnetic pole is different for each horseshoe-shaped core, and the coil energization phase of each horseshoe-shaped core is also different. The horseshoe-shaped core is formed by stacking electromagnetic steel plates bent in a C shape.
In Patent Document 5 (Hagiwara), the stator magnetic poles (pole teeth) on both sides of the E-shaped stator core are axially opposed to both end faces of the disk-shaped rotor core, and the stator pole (pole teeth) in the center of the E-shaped stator core is disk-shaped. SRM that faces the outer peripheral surface of the rotor core is proposed.

  Patent Document 6 (Nashiki) describes a stator core having a plurality of stator magnetic pole groups each constituted by a plurality of stator magnetic poles arranged at a predetermined pitch in the circumferential direction at a predetermined pitch in the axial direction, and a stator magnetic pole group of each group. An SRM having a loop core (ring coil) arranged in between and a rotor core having a plurality of rotor groups each constituted by a plurality of rotor magnetic poles arranged at a predetermined pitch in the circumferential direction at a predetermined pitch in the axial direction is suggesting. The stator magnetic poles of each stator magnetic pole group are magnetically coupled by a cylindrical back yoke, and the rotor magnetic poles of each rotor magnetic pole group are magnetically coupled by a cylindrical back yoke. However, since the SRM of Patent Document 6 has a three-dimensional rotor core and stator core, there is a problem that eddy current loss of the stator core and the rotor core is large. Although it is possible to reduce the loss by adopting the dust core, the problem of significant increase in manufacturing cost arises.

(Problems with conventional axial RM)
For motor-assisted turbochargers and in-wheel motors, explanation of the reason is omitted, but there is a strong demand for weight reduction per torque. Among the RMs, the SRM has a large torque per unit weight, but there is a problem that the torque is still large compared with the permanent magnet type synchronous motor (PM). In addition, SRM has a problem that noise and vibration are larger than PM and a problem that efficiency is poor. The existence of these problems is the reason why SRM is used only for special purpose compared with PM (for example, brushless DC motor), although the manufacturing cost can be reduced.

JP-A-01-103150 JP-A-10-112964 JP 2004-104853 A JP2004-166354 JP2007-31562A WO2006 / 123659

  The present invention has been made in view of the above problems, and an object thereof is to provide an SRM having excellent torque per unit weight and low vibration and noise. Another object of the present invention is to provide an SRM capable of reducing loss. Furthermore, an object of the present invention is to provide an SRM in which power generation control is easy.

(Object of invention)
The current production volume of switched reluctance motors (SRM) is very small. One of the causes is a large torque ripple and noise. However, switched reluctance motors have great potential as variable speed, high speed rotary motors. It is not easy to form a sinusoidal current corresponding to high speed rotation. An object of the present invention is to provide a switched reluctance motor with less torque ripple. It is another object of the present invention to provide a switched reluctance motor that is compact and capable of rotating at a high speed and capable of outputting high torque.

  A motor-assisted turbocharger for vehicle engine assist having a strong acceleration capability gives the possibility of simplification or omission of the throttle valve in addition to the reduction in size and weight of the engine. The in-wheel motor of a vehicle realizes a reduction in engine size while ensuring vehicle acceleration. However, weight reduction of these motors is very important. An object of the present invention is to realize a lightweight motor suitable for a motor-assisted turbocharger or an in-wheel motor.

  In addition, when the switched reluctance motor is rotated at a high speed, the stator coil current must be rapidly raised and lowered by the unipolar motor drive circuit. An object of the present invention is to provide a unipolar motor driving circuit for a switched reluctance motor capable of high-speed driving.

(Summary of the Invention)
In the following description, a radial gap type switched reluctance motor having a cylindrical stator core is described as an example. However, the radial gap type switched reluctance motor disclosed in this specification can be applied to an axial gap type, linear motor type, and oblique gap type switched reluctance motor. That is, the axial direction of the radial gap motor corresponds to the radial direction of the axial gap motor, and the radial direction of the radial gap motor corresponds to the axial direction of the axial gap motor. Therefore, for simplicity of understanding, the present invention claimed for the radial gap motor structure is based on the assumption that the axial gap type, linear motor type, and diagonal gap type switched reluctance motors are assumed to be read by a person skilled in the art. Includes embodiments.

In addition, some aspects of the present invention described below can also be applied to motors other than switched reluctance motors, for example, permanent magnet synchronous motors and rotors having a permanent magnet.
In the three independent inventions described below, a stator having a soft magnetic stator core wound with a stator coil composed of a plurality of phase coils, and a peripheral surface of the stator are disposed so as to be relatively rotatable with a small gap therebetween. A rotor, and a motor drive circuit for supplying a substantially trapezoidal current to each phase coil at different timings, and the stator facing surface of the rotor has soft magnetic low magnetic resistance portions at a predetermined circumferential pitch. The stator core is applied to a switched reluctance motor (SRM) having a plurality of stator magnetic poles having soft magnetism and projecting toward the rotor at a predetermined circumferential pitch. This type of SRM is well known.

(Description of the first invention)
In the SRM according to the first aspect of the invention, the stator core has a plurality of soft magnetic stator segments arranged at a predetermined circumferential pitch and extending substantially in the axial direction, and the stator segments are arranged at a predetermined axial pitch. And three or more stator magnetic poles each projecting in the direction of the substantially radial rotor, and the rotor core has a plurality of soft magnetic rotor segments arranged at a predetermined circumferential pitch and extending substantially in the axial direction. The rotor segments are arranged at axial positions where the stator segments can face at least two stator magnetic poles adjacent to each other in the axial direction of the stator segments, and the phase coils of the phases are arranged on the stator segments. A ring coil that passes through a slot provided between the stator magnetic poles and is wound in a substantially circular shape and surrounds the rotor core. The circumferential relative position between the two stator poles facing the first rotor segment and the first rotor segment is such that the two stator poles facing the second rotor segment and the second The motor drive circuit is electrically connected to the first phase coil that excites the first rotor segment. The phase of the phase current is shifted by a phase angle corresponding to the electrical angle with respect to the phase of the second phase current energized to the second phase coil for exciting the second rotor segment. Yes.

In this SRM having an axially extending stator segment, a rotor segment, and a ring coil, torque can be generated using magnet magnetic flux if a permanent magnet is fixed to the rotor segment. In this axially extending segment motor having a rotor segment with a magnet, if the magnetic resistance of the rotor segment 7 is greatly increased due to the presence of a permanent magnet, reluctance torque can hardly be expected, so this is regarded as a magnet synchronous motor. You can also.
That is, this SRM has a stator segment having three or more stator magnetic poles extending in the axial direction and a rotor segment facing the stator segment, and the rotor segment is formed by a ring coil that passes through each slot of the stator segment. Energize.

Since this SRM has a short magnetic path length, the amount of soft magnetic material having a large specific gravity can be reduced. In addition, since a ring coil is used, there is no coil end protruding from the stator core on both sides in the axial direction as compared with a conventional cylindrical motor, and a coil conductor having a large sectional area can be easily wound. Therefore, the amount of coil material having a large specific gravity can be reduced. Further, the metal housing surrounding the coil end can be made small and light by the omission of the coil end. As a result of these, the motor weight can be greatly reduced.
Further, in this motor, the ring coil can be exposed between the stator segments adjacent to each other in the circumferential direction, so that the cooling of the ring coil becomes very easy. Thereby, the current density of the ring coil can be further increased, so that further reduction in size and weight of the motor can be realized.

  In a motor having a structure in which a stator core is formed by arranging a plurality of stator segments each extending in the axial direction at a predetermined pitch in the circumferential direction, it is particularly important to support the stator segments in a motor housing. Since this SRM employs a ring coil as the stator coil, the end faces on both sides in the circumferential direction of the stator magnetic poles of the stator segment are not covered with the coil and can be supported in close contact with the motor housing. As a result, a large number of divided stator segments can be safely supported by the motor housing.

In a preferred aspect 1 of the SRM of the first invention, the ring coil has a DC coil for direct current conduction and an AC coil for alternating current conduction accommodated in each slot between the stator magnetic poles, The motor drive circuit energizes each DC coil with a direct current, and energizes the AC coil with a substantially trapezoidal alternating current.
That is, this SRM accommodates in the same slot a ring coil that forms a DC coil through which a direct current is passed and a ring coil that forms an AC coil through which an alternating current of each phase is passed. Thereby, DC magnetic flux can be utilized. This facilitates control of power generation by direct current control. In addition, even during an electric operation, it can be considered as one equivalent coil through which the sum of alternating current and direct current flows, so that the square of the sum of alternating current and direct current is obtained despite the small amplitude of alternating current. A large torque proportional to can be obtained during the inductance increase period.

In a preferred aspect 2 of the SRM of the first invention, the ring coil forming the DC coil has a smaller conductor cross-sectional area and a larger number of turns than the ring coil forming the AC coil. As a result, the copper loss of the DC coil can be reduced, the occupation ratio of the AC coil in the slot can be improved, and the copper loss of the AC coil can also be reduced.
In a preferred aspect 3 of the SRM of the first invention, the motor drive circuit is configured such that, during an electric operation, the direction of the magnetic flux formed by the AC current is opposite to the magnetic flux formed by the DC current during the inductance reduction period of the AC coil. Thus, the AC current is supplied to the AC coil in a direction in which the direction of the magnetic flux formed by the alternating current during the inductance increase period of the AC coil is the same as the magnetic flux formed by the direct current. As a result, part or all of the magnetic flux formed by the AC coil during the inductance reduction period is canceled out by the magnetic flux formed by the DC coil, so that the reverse torque can be reduced or made zero. Further, the torque in the inductance increase period can be increased by the currents of the AC coil and the DC coil.

In a preferred aspect 4 of the SRM of the first invention, the motor drive circuit forms the direct current that forms a magnetic flux that is substantially equal to and opposite in direction to the magnetic flux of the alternating current during an inductance reduction period of the AC coil during electric operation. A current is passed through the DC coil. Thereby, since almost no magnetic flux flows through the rotor segment during the inductance reduction period, the reverse torque can be made substantially zero, and the torque ripple can be greatly reduced.
In a preferred aspect, the motor drive circuit forms the AC magnetic flux that is substantially equal to the amount of the DC magnetic flux and in the opposite direction during the inductance reduction period of the AC coil in the high efficiency operation mode (or the small torque ripple operation mode). In the large torque operation mode, the AC magnetic flux that is 20 to 50% larger than the amount of the DC magnetic flux and in the opposite direction is formed during the inductance reduction period of the AC coil. Thereby, when a large torque is required, the torque can be increased. When a high efficiency or a small torque ripple is required, the copper loss can be reduced to increase the efficiency and the torque ripple can be reduced.

In addition, the trapezoidal wave direct current that is passed through the SRM is divided into a stable direct current and an alternating current, they are passed through separate coils (DC coil and AC coil), and the amplitude of the direct current Idc is further reduced during the inductance reduction period. It should be noted that the concept of this technique of substantially canceling the magnetic flux during the inductance reduction period by making it approximately equal to the average amplitude of the AC current can also be applied to a known general SRM.
In a preferred aspect 5 of the SRM of the first invention, the motor drive circuit has a single-phase full frame bridge circuit that supplies power separately to the three AC coils forming the three-phase coils. Thus, it is possible to realize an SRM that performs an operation in which currents rise and fall during different periods (see, for example, FIGS. 3 and 13).
In a preferred aspect 6 of the SRM of the first invention, the motor drive circuit has a three-phase bridge circuit that supplies a three-phase alternating current to the three AC coils that are star-connected to form the three-phase coil. The three upper arm elements of the three-phase bridge circuit are turned on in order of about 2π / 3 electrical angle, and the three lower arm elements of the three-phase bridge circuit are turned on in order of about 4π / 3 electrical angle. The direct current Idc flowing through the DC coil is about half the current of the three upper arm elements of the three-phase bridge circuit. Accordingly, the switched reluctance motor according to claim 4. With a simple three-phase bridge circuit that drives the three-phase coils connected in a star shape, the alternating current magnetic flux during periods other than the inductance increasing period can be canceled by the direct current magnetic flux.
In a preferred aspect 7 of the SRM of the first invention, the motor drive circuit has a capacitor connected in parallel with the DC coils connected in series. As a result, it is possible to reduce switching noise generated when the DC current flowing through the DC coil is subjected to switching control, and to greatly reduce the AC induced voltage induced in the DC coil. It should be noted that the present invention can also be applied to a known general SRM having a multi-phase DC coil.

  In a preferred aspect 8 of the SRM of the first invention, the motor drive circuit has a constant current circuit for supplying a substantially constant current to the DC coils connected in series. Thereby, the fluctuation | variation of the direct current of a DC coil by the induced voltage induced | guided | derived to a DC coil by the movement of a rotor segment or the current change of an AC coil can be reduced significantly. It should be noted that the present invention can also be applied to a known general SRM having a multi-phase DC coil.

  In a preferred aspect 7 of the SRM of the first invention, the motor drive circuit is based on an oscillation circuit for passing a high-frequency current through the DC coils connected in series with each other and a voltage drop of the plurality of DC coils due to the high-frequency current. And a rotor rotation angle detection circuit for detecting the rotation angle of the rotor. Thus, by using an existing DC coil, it is possible to detect a rotor rotation angle that changes in accordance with a change in inductance of the DC coil that depends on the relative positional relationship with the rotor segment at rest and during rotation. It should be noted that the present invention can also be applied to a known general SRM having a multi-phase DC coil.

  In a preferred aspect 8 of the SRM of the first invention, the stator segment and the rotor segment are formed by laminating a number of soft magnetic steel plates extending in a substantially axial direction in a tangential direction of the rotor, and the stator segment and The radial ends of the rotor segments are arranged with a step between them so as to be approximately circular as a whole. In addition to the SRM, this aspect can be applied to other types of motors that use axially extending segments. In this way, the iron loss of the axially extending segment SRM can be reduced using a relatively simple manufacturing process and an inexpensive material. In addition to the SRM, this aspect can be applied to other types of motors that use axially extending segments.

  In a preferred aspect 9 of the SRM of the first invention, the rotor segment includes the M-th axial rotor facing the N-th (N is an integer of 2 or more) and N + 1-th stator magnetic poles of the stator segment. And the M + 1-th rotor segment facing the N + 1 and N + 2 stator poles in the axial direction of the stator segment, and the rotor core includes the M-th rotor segment and the M + 1-th rotor segment. A high magnetoresistive region having a large magnetoresistance is located between the rotor segment. In this way, the Nth and N + 2th stator magnetic poles are magnetically short-circuited by circumferential magnetic flux leakage from the Mth rotor segment to the M + 1th rotor segment, so that the Nth and N + 1th stator magnetic poles It is possible to solve the problem that the inductance of the coil between the coils or the coil between the (N + 1) th and (N + 2) th stator poles is not sufficiently small.

  In a preferred aspect 10 of the SRM of the first invention, at least one of the stator segment and the rotor segment is formed by laminating a number of soft magnetic steel plates extending in a substantially axial direction in a substantially tangential direction of the rotor. The first laminated portion is configured by combining a second laminated portion formed by laminating a number of soft magnetic steel plates extending in a substantially tangential direction in the axial direction of the rotor. In this way, when the stator segment and the rotor segment partially overlap in the circumferential direction, magnetic flux concentration is locally generated in the stator magnetic pole and rotor segment of the stator segment, or through a plurality of soft magnetic steel plates in the circumferential direction. The problem that the eddy current increases due to the flow of the magnetic flux can be solved.

In a preferred aspect 11 of the SRM of the first invention, the first laminated portion has a hole portion that is located in the vicinity of the tip end portion of the stator magnetic pole and is opened in a substantially circumferential direction to accommodate the second laminated portion. Thereby, the magnetic flux concentration reduction effect and the eddy current reduction effect can be improved.
In a preferred aspect 12 of the SRM of the first invention, the SRM includes an adhesive layer that contains soft magnetic iron powder and adheres the second laminated portion to the first laminated portion. Thereby, the magnetic resistance between the first stacked unit and the second stacked unit can be reduced, and the mechanical integrity between the first stacked unit and the second stacked unit can be improved.

In a preferred aspect 13 of the SRM of the first invention, the second laminated portion is configured by laminating substantially C-shaped soft magnetic steel plates in the axial direction and the radial direction, and a pair of tip portions are directed toward the rotor. It consists of a protruding C-shaped core. Thereby, a 2nd lamination | stacking part can be manufactured easily.
In a preferred aspect 14 of the SRM of the first invention, the second laminated portion spirally winds a long soft magnetic steel plate having a pair of projecting portions projecting on both sides in the width direction, and the pair of projecting portions are disposed on the rotor. It is formed by bending toward Thereby, a 2nd lamination | stacking part can be manufactured easily.

In a preferred aspect 15 of the SRM of the first invention, the stator core has a C-shaped cross section that wraps a portion other than the rotor side of the ring coil, and a soft magnetic steel plate is laminated in a direction away from the ring coil. It has a configured C-shaped core. Thereby, a stator segment can be manufactured easily.
In a preferred aspect 16 of the SRM of the first invention, the C-shaped core spirally winds a long soft magnetic steel plate having a pair of protrusions protruding on both sides in the width direction, and the pair of protrusions on the rotor. It is formed by bending toward it. In this way, a large number of C-shaped cores (claw pole cores) arranged at a predetermined pitch in the circumferential direction can be manufactured at once by a simple manufacturing method. In this aspect, since the C-shaped cores (stator segments) arranged in the circumferential direction are connected by the belt-shaped portions extending in the circumferential direction of the soft magnetic steel plate, the mechanical strength of the stator core can be increased. . This strip portion does not affect the magnetic field of the ring coil. By arranging a plurality of C-shaped cores adjacent to each other in the axial direction (radial direction in the case of an axial gap motor), multiphase SRM is possible. It should be noted that the present invention can be applied to a known general motor having a C-shaped core.

  In a preferred aspect 17 of the SRM of the first invention, the ring coil is formed by spirally winding a long insulating coated conductive metal plate having a constant thickness in the arrangement direction of the plurality of stator magnetic poles of one stator segment. Each turn of the ring coil is laminated in the direction of arrangement of the plurality of stator magnetic poles of the stator segment. Thereby, the ring coil can be easily accommodated in the slot of the stator segment, and the heat dissipation of the stator coil is also improved. It should be noted that the present invention can be applied to a known general motor using a ring coil.

  In a preferred aspect 18 of the SRM of the first invention, the rotor core is fixed to the outer peripheral surface of the boss portion and is protruded on both sides in the axial direction of the boss portion. The rotor segment, and the rotor segment has a pair of projecting end portions projecting axially from both end surfaces of the boss portion, and the ring coil and the stator magnetic pole are projected from the rotor segment. It arrange | positions at the radial direction both sides of an edge part. Thereby, the axial direction length of a motor can be shortened. In addition to the SRM, this aspect can be applied to other types of motors that use axially extending segments.

(Explanation of the second invention)
In the SRM of the second invention, the phase coil is disposed between the inductance increase period and the next inductance decrease period, and is disposed between the peak period where the inductance change is small, and between the inductance decrease period and the next inductance increase period. And a bottom period in which the inductance change is small, and an inductance increase period of the other phase coil is set substantially continuously to the inductance increase period of the one-phase coil, and the motor drive circuit is set in the bottom period. It is characterized in that the rising of the energizing current to the phase coil is almost completed and the falling of the energizing current to the phase coil is almost completed during the peak period. It should be noted that the present invention can be applied to a known general SRM.

That is, the present invention energizes most of the maximum value of the energization current to the phase coil (preferably 80%, more preferably 90% or more) before the start of the inductance increase period of the phase coil, and After the end of the phase coil inductance increase period, most of the maximum value (preferably 80%, more preferably 90% or more) of the energization current to the phase coil is attenuated.
In the present invention, the rising and falling periods of the phase current in which the phase coil current greatly changes are excluded from the inductance increase period (during electric operation) in which the phase coil inductance greatly increases. In this way, the torque during the phase current rise and fall periods can be significantly reduced. For this reason, the torque caused by the phase current flowing in one phase coil can be sharply raised and lowered. Therefore, the torque ripple can be greatly reduced by making this square torque continuous in each phase. This aspect can also be applied to other known switched reluctance motors. In addition, since reluctance torque does not generate | occur | produce in a bottom period and a peak period, this does not produce a torque ripple.

  In a preferred aspect 1 of the SRM of the second invention, the stator core has a plurality of soft magnetic stator segments arranged at a predetermined pitch in the circumferential direction and extending substantially in the axial direction, and each stator segment has a shaft A plurality of soft magnetic poles arranged at a predetermined pitch in the direction and projecting substantially in the radial direction toward the rotor, and the rotor core is arranged at a predetermined pitch in the circumferential direction and extends in a substantially axial direction. The rotor segments are arranged at axial positions where the stator segments can face at least two stator poles adjacent to each other in the axial direction of the stator segments, and face the first rotor segment. The circumferential relative position between the two stator magnetic poles and the first rotor segment is the same as the second rotor segment. A predetermined electrical angle in the circumferential direction relative to the circumferential relative position between the two stator poles facing and the second rotor segment, and the circumferential pitch of the rotor segment and the circumferential pitch of the stator segment , The stator magnetic pole has a circumferential width of approximately electrical angle π, and the rotor segment has a circumferential width of approximately electrical angle 2π / 3.

In this way, it is possible to continuously generate an inductance increase period of each phase in which a substantially constant torque is generated, so that torque ripple can be greatly reduced and sufficient bottom and peak periods are ensured. Can do.
In a preferred aspect 2 of the SRM of the second invention, the motor drive circuit advances the energization start time in the bottom period when generating a large torque, and sets the energization start time in the bottom period when generating a small torque. Delay. Thereby, when generating a small torque, the copper loss of the electric current rising period which does not generate a torque can be reduced.

(Explanation of the third invention)
The SRM of the third invention is characterized in that the motor drive circuit includes an acceleration circuit for accelerating a rising period or a falling period of a phase current energized to the phase coil. It should be noted that the present invention can be applied to a known general SRM. Thereby, since the average current value in the inductance increase period can be improved, the torque can be increased even if the inductance increase period is shortened during high-speed operation.

  In a preferred aspect 1 of the SRM of the third invention, the acceleration circuit includes a high-side switch that connects a high potential end of a DC power source and a high potential end of a phase coil, a low potential end of the DC power source, and the phase coil. A low-side switch that connects the low-potential end of the DC power source, a low-side diode that connects the low-potential end of the DC power source and the high-potential end of the phase coil, a reactor and a high-side diode connected in series, and the DC A high-side bypass circuit that connects a high-potential end of a power source and a low-potential end of the phase coil.

  In this way, when the energization from the DC power supply to the phase coil is interrupted by turning off the high-side switch or the low-side switch, the energy stored in the phase coil causes the DC power supply to pass through the low-side diode, phase coil, and high-side bypass circuit. Power regeneration from the low potential end to the high potential end occurs. At this time, since the reactor of the high-side bypass circuit generates a counter electromotive force, the phase coil needs to generate a voltage higher than the voltage of the DC power supply, and the regenerative current is reduced accordingly, and the magnetic energy of the phase coil is Decreases rapidly. Magnetic energy is stored in the reactor, and this reactor energy can be regenerated from the low potential end of the DC power source to the high potential end through a diode or the like connected in antiparallel with the low side switch. According to this aspect, since the regeneration period can be shortened, the excitation current energizing period before the regeneration period can be extended. Thereby, torque can be increased. This embodiment can also be applied to other known switched reluctance motors. The high side switch may be a diode having an anode connected to a high potential end of a DC power supply.

In a preferred aspect 2 of the SRM of the third invention, one end of the reactor is connected to a high potential end of the DC power supply, and the other end of the reactor is connected to a low potential of different phase coils through different high side diodes. Connected to the end. Thereby, the number of reactors can be reduced.
In a preferred aspect 3 of the SRM of the third invention, the acceleration circuit includes a high-side switch that connects a high potential end of a DC power source and a high potential end of a phase coil, a low potential end of the DC power source, and the phase coil. A low-side switch that connects the low-potential end of the DC power supply, a reactor having one end connected to the high-potential end of the DC power supply, an acceleration switch that connects the other end of the reactor and the low-potential end of the DC power supply, A high-side diode connecting a connection point between the reactor and the acceleration switch to a high potential end of the phase coil;

  If it does in this way, just before starting energization to a phase coil, first, an acceleration switch will be energized and magnetic energy will be accumulated in a reactor. Thereafter, the acceleration switch is turned off, and energization from the DC power source to the phase coil is started by turning on the low side switch. A voltage that is higher than the potential at the high potential end of the DC power supply by the voltage of the reactor is applied to the high potential end of the phase coil. As a result, a current flows rapidly through the phase coil, and the rising period of the excitation current can be shortened. As a result, the energizing period thereafter can be extended, and the torque can be increased. This embodiment can also be applied to other known switched reluctance motors. The high side switch may be a diode having an anode connected to the high potential end of the DC power supply.

  In a preferred aspect 4 of the SRM according to the third aspect of the invention, the connection point between the reactor and the acceleration switch is connected to the other end of the different phase coils through different backflow prevention diodes. Thereby, the number of reactors can be reduced. In the preferred embodiment 5, the reactor for accelerating the current rising and the reactor for accelerating the current falling are common.

  In a preferred aspect 5 of the SRM of the third invention, the accelerating circuit includes a switching element that connects a low potential end of the phase coil and a low power supply bus, and a diode for preventing backflow, A connection point between a low potential end and a high potential end of the switching element and a high potential end of the assist coil are connected through the backflow prevention diode, and the magnetic energy of the phase coil is changed when the switching element is turned off. Flow through the assist coil. In this way, the magnetic energy accumulated in the phase coil at the time of turning off the current is supplied to the assist coil wound together with the phase coil to be excited next, so that the current ripple is reduced and the magnetic energy to be regenerated is reduced. Can be rapidly extinguished and the excitation magnetic flux can be increased rapidly, so that the torque can be increased. The present invention can also be applied to other known switched reluctance motors.

1 is a block circuit diagram illustrating an overall configuration of a motor device according to a first embodiment. It is a schematic diagram which shows the structure of SRM of FIG. FIG. 2A is a schematic diagram showing one of a plurality of stator segments constituting the stator core of this SRM, and FIG. 2B shows the stator magnetic poles belonging to the two stator segments and the rotor segments of the respective phases. It is the circumferential direction expanded view which shows the positional relationship of these. 3 is a timing chart showing waveforms of inductance, current, and torque of the SRM in FIG. 2. It is a flowchart which shows the torque control of SRM of FIG. FIG. 2 is a circuit diagram showing a first example of the unipolar drive circuit of FIG. 1. FIG. 4 is a circuit diagram illustrating a second example of the unipolar drive circuit of FIG. 1. FIG. 4 is a circuit diagram illustrating a third example of the unipolar drive circuit of FIG. 1. FIG. 6 is a circuit diagram showing a fourth example of the unipolar drive circuit of FIG. 1. FIG. 6 is a schematic diagram in the axial direction of one stator segment of the SRM of Example 2. 10 is a timing chart showing waveforms of inductance, current, and torque of the SRM of FIG. 9. FIG. 10 is a circuit diagram showing a motor drive circuit of the SRM of FIG. 9. 10 is a flowchart showing torque control of the SRM of FIG. 6 is a schematic diagram illustrating the structure of an SRM of Example 3. FIG. FIG. 13A is a developed circumferential view showing the positional relationship between the stator magnetic poles belonging to the two stator segments and the rotor segments of the respective phases, and FIG. 13B shows a plurality of components constituting the SRM stator core. It is an axial direction schematic diagram which shows one of the stator segments. 14 is a timing chart showing waveforms of inductance, current, and torque of the SRM of FIG. It is a block circuit diagram which shows the three-phase inverter which forms the three-phase alternating current of FIG. It is a schematic diagram which shows the deformation | transformation aspect 4 of Example 2, 3. FIG. FIG. 17 is a schematic development view showing the operation of the SRM shown in FIG. 16. FIG. 16A shows a state where the electrical angle is zero. FIG. 16B shows a state of an electrical angle π. It is a schematic diagram which shows the deformation | transformation aspect 5 of Example 2, 3. FIG. It is a schematic diagram which shows the deformation | transformation aspect 5 of Example 2, 3. FIG. 6 is a schematic diagram illustrating an SRM of Example 4. FIG. It is a model radial direction side view of SRM of FIG. 10 is a schematic partial axial sectional view showing an SRM of Example 5. FIG. FIG. 23 is a schematic partial radial cross-sectional view of the SRM of FIG. 22. 10 is a schematic diagram for explaining an SRM of Example 6. FIG. FIG. 24A is a side view of the ring coil. FIG. 24B is a plan view of the ring coil. FIG. 25 is a schematic explanatory view showing a method of accommodating the ring coil of FIGS. 23 and 24 in the slot of the radial gap motor. FIG. 25 is a schematic explanatory view of Example 7 showing a method of accommodating the ring coil of FIGS. 23 and 24 in a slot of an axial gap motor. FIG. 10 is a radial sectional view showing a stator magnetic pole of an SRM according to an eighth embodiment. FIG. 10 is an explanatory diagram for explaining an SRM according to a ninth embodiment. FIG. 28A is an explanatory view showing a circumferential magnetic flux leakage state between circumferentially laminated soft magnetic steel plates. FIG. 28B is an explanatory view showing a structure for reducing the circumferential magnetic flux leakage of FIG. FIG. 10 is a schematic diagram illustrating the structure of an SRM according to Example 10. FIG. 29A is an axial sectional view of one stator segment 3A. FIG. 29B is a cross-sectional view taken along line AA of the stator segment 3A in FIG. It is explanatory drawing which shows the manufacture example of the 2nd lamination | stacking part of FIG. FIG. 10 is a schematic diagram showing the structure of a rotor segment of Example 10. FIG. 31A is an axial sectional view of one rotor segment 7. FIG. 31B is a plan view of the rotor segment 7 of FIG. 31A as viewed from the electromagnetic gap G side. It is explanatory drawing which shows the other manufacturing method of the 2nd lamination | stacking part of the stator segment of SRM of Example 10. FIG. FIG. 32A is a plan view showing a punched state of the electromagnetic steel sheet formed in a band shape. FIG. 32B is a schematic perspective view showing a state in which the protruding portion of the belt-shaped electromagnetic steel sheet is bent. FIG. 10 is a schematic diagram showing a deformation mode of a stator segment of the SRM of Example 10. FIG. 33A is a partial front view of the stator segment extending in the axial direction. FIG. 33B is a side view of the stator segment 3 of FIG. 33A as viewed in the axial direction. It is a front view of the C-shaped core for explaining Example 11. It is a side view of the C-shaped core of FIG.

Hereinafter, a preferred embodiment of the present invention will be described by taking a radial gap motor type of an inner rotor as an example. However, the present invention should not be construed as being limited to the following embodiments, and those skilled in the art will realize the technical idea of the present invention based on other well-known techniques conceived based on the matters described in this specification. Of course you can. For example, by considering the axial direction of the embodiment as the radial direction, the SRM of the embodiment can be applied to an axial gap type SRM, and by setting the circumferential direction of the SRM of the embodiment to a linear direction, the SRM of the embodiment Can be applied to linear SRM. Furthermore, the technical devices described in the following embodiments can be applied to motors other than the SRM.
Technical terms employed in the following embodiments will be described below. The “stator segment” is a member having soft magnetism and extending substantially in the axial direction, and a plurality of stator segments arranged at a predetermined circumferential pitch constitute a stator core. The “rotor segment” is a member having soft magnetism and extending substantially in the axial direction, and a plurality of rotor segments arranged at a predetermined circumferential pitch constitute a rotor core. The ring coil is an armature coil wound around the rotor core or the rotating shaft. The ring coil is accommodated in a gap (so-called slot) between two axially adjacent stator magnetic poles. The multiphase SRM has a stator coil composed of a phase coil constituted by a ring coil of each phase. The substantially axial direction mentioned here includes an example in which the rotor segment and the stator segment are skewed. In the case of a radial gap motor, it is preferable to twist when the rotor segment or the stator segment is skewed. By twisting, the radial end surface of the segment can be made into a substantially cylindrical surface. The SRMs of the following embodiments having the above-described stator segment, rotor segment, and ring coil are also referred to as “axially extending segments SRM”.

Example 1
The structure and control of the axially extending segment SRM of the present invention will be described with reference to the first embodiment.

(overall structure)
FIG. 1 is a block circuit diagram illustrating the overall configuration of the motor device according to the first embodiment. Reference numeral 900 denotes a DC power source, reference numeral 901 denotes a drive circuit, reference numeral 902 denotes a three-phase axially extending segment SRM (hereinafter also simply referred to as SRM), and reference numeral 903 denotes a motor controller. The drive circuit 901 and the motor controller 903 constitute a motor drive circuit. In this embodiment, since a substantially trapezoidal direct current is applied to each coil of the SRM 902, a known three-phase unipolar type motor drive circuit is employed as the drive circuit 901. The motor controller 903 reads the rotation speed command Ns and the torque command Ts from the outside, and reads the motor rotation angle and the three-phase current value from the three-phase SRM 902. The motor controller 903 feedback-controls the drive circuit 901 based on input data in accordance with a motor control program stored in a built-in microcomputer.

(Structure of SRM)
The structure of the SRM 902 will be described with reference to FIG. FIG. 2A is a schematic view showing one of a plurality of stator segments constituting the stator core of the SRM 902, and FIG. It is the circumferential direction expanded view which shows these positional relationships. In the following drawings, AX indicates the axial direction, RA indicates the radial direction, and PH indicates the circumferential direction.

This SRM 902 is an inner rotor type radial gap motor, and has a stator 1 fixed to an inner peripheral surface of a housing (not shown) and a cylindrical rotor accommodated inside the stator 1 in the radial direction. The stator 1 includes a stator core made of a soft magnetic steel plate and a stator coil made up of ring coils 4U, 4V, and 4W wound around the stator core. The stator core is composed of an even number of stator segments 3 fixed to the inner peripheral surface of the nonmagnetic housing at an electrical angle of 2π pitch. Each stator segment 3 is made of a soft magnetic material and extends in the axial direction.
. FIG. 2A shows one stator segment 3. The stator segment 3 is made of a soft magnetic material. The stator segment 3 includes stator magnetic poles 31 to 34 that protrude inward in the radial direction at a predetermined distance in the axial direction, and a base portion of each of the stator magnetic poles 31 to 33, that is, a radially outer end that extends in the axial direction. A short-circuited stator yoke 30 and slots 36 to 38 are provided. The radially inner ends of the stator magnetic poles 31 to 34 have claw portions 39 that protrude in the axial direction. The claw portion 39 protrudes in a direction that narrows the openings of the slots 36 to 38. After all, the stator core is composed of a first stator magnetic pole group composed of N (N is an even number of 2 or more) stator magnetic poles 31, a second stator magnetic pole group composed of N stator magnetic poles 32, and N stator magnetic poles 33. And a fourth stator magnetic pole group composed of N stator magnetic poles 34.

  The ring coil 4U forming the U-phase coil penetrates the slot 36 between the stator magnetic poles 31 and 32 in the circumferential direction (PH). Ring coil 4V forming a V-phase coil penetrates slot 37 between stator magnetic poles 32 and 33 in the circumferential direction. The ring coil 4W forming the W-phase coil penetrates the slot 38 between the stator magnetic poles 33 and 34 in the circumferential direction. Ring coils 4U, 4V and 4W each having a predetermined number of turns are formed in a ring shape surrounding a rotor (not shown). The drive circuit 901 energizes the U-phase current IU to the ring coil 4U, the V-phase current IV to the ring coil 4V, and the W-phase current IW to the ring coil 4W.

  Cylindrical rotors (not shown in FIG. 2A) are bosses (not shown) that are non-magnetic cylindrical members fitted and fixed to a rotary shaft that is rotatably supported by the housing, respectively. It has N groups of rotor segment groups consisting of rotor segments 7U, 7V and 7W. The rotor segments 7U, 7V, and 7W are fixed to the outer peripheral surface portion of the boss portion so as to face the stator segment 3. Rotor segments 7U, 7V, and 7W are arranged at an electrical angle of 2π pitch. The rotor segments 7U, 7V, 7W are made of a soft magnetic material.

  The rotor segments 7U, 7V, 7W have a circumferential position and an axial position indicated by broken lines in FIG. The N rotor segments 7U, which are U-phase rotor segments, are arranged at positions where they can face the stator magnetic poles 31 and 32. N rotor segments 7V, which are V-phase rotor segments, are arranged at positions where they can face the stator magnetic poles 32 and 33. N rotor segments 7W, which are W-phase rotor segments, are arranged at positions where they can face the stator magnetic poles 33 and 34. The rotor segments 7U, 7V, and 7W are arranged so as to be shifted from each other in the circumferential direction by an electrical angle (2/3) π pitch.

  As shown in FIG. 2B, a small gap g extending in the axial direction is formed between the rotor segments 7U and 7V and between the rotor segments 7V and 7W. The small gap g may be a gap or a nonmagnetic member. A small gap g schematically shown by a thick black line in FIG. 2B increases the magnetic resistance (rotor segment magnetic resistance) between the rotor segments 7U, 7V, and 7W. As a result, leakage magnetic fluxes (Φu−Φv) and (Φv−Φw) flowing in the circumferential direction between the rotor segments 7U, 7V, and 7W are reduced.

  FIG. 2B shows the relative positional relationship in the circumferential direction and the axial direction between the tip surfaces of the stator magnetic poles 31 to 34 and the stator facing surfaces of the rotor segments 7U, 7V, and 7W. In this embodiment, the circumferential width of the stator magnetic poles 31 to 34 arranged in the axial direction is an electrical angle π. The circumferential width of the rotor segments 7U, 7V, 7W is an electrical angle (2/3) π. In FIG. 2B, the axial widths of the stator magnetic poles 31 and 34 are narrower than the axial widths of the stator magnetic poles 32 and 33, but they may be equal.

(Electric operation)
When the U-phase current Iu (or IU) flows through the ring coil 4U, the magnetic flux Φu (or ΦU) flows through the stator magnetic poles 31 and 32 to the rotor segment 7U in the axial direction. When the V-phase current Iv (or IV) flows through the ring coil 4V, the magnetic flux Φv (or ΦV) flows through the stator magnetic poles 32 and 33 to the rotor segment 7V in the axial direction (AX). When the W-phase current Iw (or IW) flows through the ring coil 4W, the magnetic flux Φw (or ΦW) flows axially through the stator magnetic poles 33 and 34 to the rotor segment 7W.
FIG. 3 shows waveforms of the inductance Lu of the ring coil 4U, the inductance Lv of the ring coil 4V, the inductance Lw of the ring coil W, and the waveforms of the three-phase currents Iu, Iv, and Iw. The circumferential width of the stator magnetic poles 31 to 34 is π, the circumferential width of the rotor segments 7U, 7V, and 7W is (2/3) π, and the circumferential width of the gap between two adjacent stator segments is π. Therefore, the three-phase inductances Lu, Lv, and Lw have a bottom period Tb in which the inductance is the minimum value and a peak period Tp in which the inductance is the maximum. The bottom period Tb and the peak period Tp are electrical angles (1/3) π.

As is well known, a three-phase trapezoidal wave current is applied during the inductance increase period Ti of the ring coils 4U, 4V, 4W in order to operate the SRM motor. More specifically, since the ring coils 4U, 4V, and 4W have inductance, it takes time for the current to rise even when a substantially rectangular wave voltage is applied to the ring coils 4U, 4V, and 4W. Similarly, even if the voltage applied to the ring coils 4U, 4V, 4W is suddenly turned off, a magnetic energy regenerative current flows, so that it takes time for the current to fall. For this reason, a substantially trapezoidal current flows in the ring coils 4U, 4V, and 4W (see FIG. 3).
In this embodiment, the rise of the current is almost finished before the start of the inductance increase period Ti, and the fall of the current is started almost after the end of the inductance increase period Ti. Furthermore, the current rise is almost completed in the bottom period Tb, and the current fall is almost completed in the peak period Tp. Here, “substantially” means 85% or more, more preferably 90% or more, and even more preferably 95% or more.

  The reluctance torque of the SRM is proportional to the product of the rotor angle differential value (dL / dθ) of the inductance and the square of the current (I). In this embodiment, the current change is almost completed in the bottom period Tb and the peak period Tp in which the inductance hardly changes. For this reason, the current hardly changes during the inductance increase period Ti. Since the inductance increase rate during the inductance increase period Ti can be regarded as being substantially constant, the torque of each phase eventually becomes substantially constant during the inductance increase period Ti of each phase. As a result, the combined torque ΣT of this SRM becomes substantially constant as shown in FIG. 3, and the torque ripple and associated vibration noise can be made very small.

Since the SRM 902 is made of a small soft magnetic material in which the stator yoke 30 of the stator segment 3 and the rotor segments 7U, 7V, and 7W extend in the axial direction, the magnetic vibration and noise are small. Since the magnetic flux of the SRM 902 flows through the stator yoke 30 in the axial direction, the length of the magnetic circuit is short, so that iron loss and motor weight can be reduced. Since this SRM 902 has a stator coil constituted by a ring coil, it is possible to simplify difficult winding work and to omit a coil end. In a conventional motor, it is very difficult to wind a stator coil having a large coil cross-sectional area around a slot having a narrow opening.
Both the stator core and the rotor core described above are constituted by soft magnetic segments extending in the axial direction (in other words, both the stator core and the rotor core have completely or almost no magnetic path flowing in the circumferential direction), and the ring coil has SRM has not been known in the past.

The SRM 902 has a bottom period Tb and a peak period by making the circumferential width of the rotor segments 7U, 7V, and 7W narrower than both the circumferential width of the stator magnetic poles 31 to 34 and the circumferential width of the gap between the stator magnetic poles. Since Tp is set and the current rise and fall are substantially completed during the bottom period Tb and the peak period Tp, the ripple of the composite torque can be greatly reduced.
Note that the bottom period Tb and the peak period Tp can be shortened by shortening the time required for the rise and fall of the current (rise time and fall time). That is, in FIG. 2, the circumferential width of the rotor segments 7U, 7V, 7W can be increased. Since the current in the bottom period Tb and the peak period Tp causes a substantially useless copper loss, it is preferable to shorten the rise time and the fall time. This point will be described later.

  Furthermore, the circumferential width of the narrow rotor segments 7U, 7V, 7W makes it possible to provide a small gap g between the rotor segments 7U, 7V, 7W of the respective phases adjacent to each other in the circumferential direction. This large magnetoresistance with a small gap significantly reduces the circumferential leakage flux (Φu−Φv) and (Φv−Φw) shown in FIG. For this reason, it is possible to greatly reduce the leakage of the magnetic flux in the circumferential direction, which increases iron loss (hysteresis loss and eddy current loss) without involving torque. This small gap g is particularly important in the following embodiments in which the rotor segments 7U, 7V, and 7W are formed by laminating thin electromagnetic steel plates in the circumferential direction. That is, in the circumferential laminated electromagnetic steel sheet, the magnetic flux flowing in the circumferential direction flows through each electromagnetic steel sheet in the thickness direction, so that the eddy current increases. This problem can be satisfactorily improved by installing the above-described small gap g between the rotor segments 7U, 7V, and 7W of the respective phases.

(Power generation operation)
When a direct current is passed through the ring coils 4U, 4V, and 4W, a power generation voltage can be generated in the ring coils 4U, 4V, and 4W by rotation of the rotor. In this case, since the stator magnetic poles 32 and 33 share two phases, the direction of the DC magnetic flux formed in the stator magnetic poles 32 and 33 is the same due to the DC current flowing through the three ring coils 4U, 4V, and 4W. It is preferable to pass a direct current.

(Control of energization start timing)
The motor torque control performed by the motor controller 903 will be described with reference to FIG. First, the rotation speed command Ns and the torque command Ts are read from the outside, and the rotor rotation angle θ and the three-phase currents Iu, Iv, and Iw are read from the rotor rotation angle detection circuit and the phase current detection circuit (not shown) (S104).
Next, the amplitudes of the trapezoidal three-phase currents Iu, Iv, and Iw that energize the ring coils 4U, 4V, and 4W are calculated based on the read torque command Ts (S102). That is, the motor controller 903 calculates the amplitude of the current I based on the stored mathematical formula (T = dL / dθ · I · I), and sets it as the amplitude of the steady period of Iu, Iv, and Iw. DL / dθ is an inductance increase rate of each ring coil 4U, 4V, 4W in the inductance increase period Ti. In this embodiment, a value A of dL / dθ at a predetermined rotor angular velocity ωo is stored, and dL / dθ at an arbitrary angular velocity ω is calculated from the following equation.

dL / dθ = (ω / ωo) · A

Of course, dL / dθ may be calculated more precisely by using a more complicated equation or map in consideration of the inductance reduction due to magnetic saturation and the shape effect of the stator magnetic pole and rotor segment.
Next, the rising timing ΔT of the three-phase currents Iu, Iv, and Iw is set based on the calculated amplitude of the current I (= average amplitude during the steady period of Iu, Iv, and Iw). Note that the rise timing ΔT referred to here means that energization is started from a point that is back by the time ΔT from the start point of the inductance increase period Ti shown in FIG. When the three-phase currents Iu, Iv, Iw are large, the time ΔT until it reaches a substantially steady state becomes long, and when the three-phase currents Iu, Iv, Iw are small, the time ΔT until it reaches a steady state. Becomes shorter. In FIG. 3, ΔT indicates the case where the three-phase currents Iu, Iv, Iw indicated by the solid lines are large, and ΔT ′ indicates the case where the three-phase currents Iu, Iv, Iw indicated by the broken lines are small. ΔT is calculated by substituting the current I into a map indicating the relationship between ΔT and the amplitude of the current I stored in advance in the motor controller 903.

Thus, the three-phase currents Iu, Iv, and Iw can be controlled so as to be in a substantially steady state at the start of the inductance increase period Ti. As a result, torque ripple can be reduced while reducing useless copper loss in the bottom period Tb of inductance. In FIG. 3, Tu is the U-phase torque, Tv is the V-phase torque, and Tw is the W-phase torque.
The motor controller 903 feedback-controls the drive circuit 901 based on the difference between the command values of the three-phase currents Iu, Iv, Iw obtained from the torque command Ts and the detected values of the detected three-phase currents Iu, Iv, Iw. This motor feedback control itself is the same as the conventional one. Prior to this torque feedback control, the three-phase currents Iu, Iv are used to converge the speed to the rotational speed command Ns based on the deviation between the angular speed ω obtained from the detected rotor rotational angle θ and the rotational speed command Ns. , Iw is feedback controlled. Further, the motor controller 903 determines the timing of the inductance increase period Ti of each phase based on the detected rotor rotation angle θ. Since these controls are essentially the same as those of the conventional SRM, description thereof is omitted.

(Reduction of torque ripple)
The SRM of this embodiment has a smaller torque ripple and noise than the conventional SRM because the substantially trapezoidal direct current substantially maintains a steady state during the inductance increase period Ti. By sharply raising and lowering the current, an increase in copper loss can be suppressed. Note that the number of phases of the SRM 902 is not limited to three and may be further increased. The bottom period Tb and the peak period Tp can be realized by adjusting the circumferential width of the stator magnetic pole and the circumferential width of the rotor magnetic pole (region of the rotor segment facing the stator magnetic pole).

(Unipolar drive circuit example 1)
An improved circuit of the unipolar type drive circuit 901 for supplying a substantially trapezoidal three-phase DC current to the SRM 902 will be described with reference to FIG. This driving circuit 901 can also be applied to driving a conventional SRM.
This drive circuit 901 has a U-phase drive circuit A, a V-phase drive circuit B, a W-phase drive circuit C, and a reactor R. These phase drive circuits A to C are the same as known SRM drive circuits. 100U is a U-phase coil, 100V is a V-phase coil, and 100W is a W-phase coil. Reference numerals 101U, 101V, and 101W denote high-side switches that individually connect the high potential end 102 of the DC power source and the high potential ends of the respective phase coils 100U, 100V, and 100W. The high side switches 101U, 101V, and 101W are preferably MOS transistors, but may be diodes. 103U, 103V, and 103W are low-side switches for PWM control that individually connect the low potential end 104 of the DC power supply and the low potential ends of the phase coils 100U, 100V, and 100W. Reference numeral 105 denotes a low-side diode that individually connects the low potential end 104 of the DC power source and the high potential ends of the phase coils 100U, 100V, and 100W. Reference numeral 106 denotes a high-side diode that individually connects one end of the reactor R and the low potential end of each phase coil 100U, 100V, 100W. The other end of the reactor R is connected to the high potential end 102 of the DC power supply. The reactor R and the high side diode 106 constitute a high side bypass circuit.

  The operation of this drive circuit will be described. When the energization of the low-side switch 103U is cut off, the magnetic potential accumulated in the phase coil 100U causes the high-potential end from the low-potential end 104 of the DC power source through the low-side diode 105, the phase coil 100U, the high-side diode 106, and the reactor R. A regenerative current flows to 102 as is well known. At this time, due to the counter electromotive force of the reactor R, the phase coil 100U needs to generate a higher voltage than in the prior art in which the high-side diode 106 supplies a regenerative current to the high potential end 102 of the DC power supply. For this reason, although the regenerative current which flows into the phase coil 100U becomes small, since the regenerative voltage is high, the magnetic energy attenuate | damps rapidly. Therefore, according to this circuit, the regenerative current can be rapidly decreased, and the torque can be increased by extending the energization period to the phase coil 100U correspondingly. At this time, magnetic energy is accumulated in the reactor R. This magnetic energy is supplied to the high potential end 102 of the DC power supply through the low-side switch (eg, 103 V) in the on state, the high-side diode 106 of the V-phase drive circuit, and the reactor R. Can be regenerated.

The fact that the low-side switch (for example, 103V) is in an ON state means that an excitation current flows through the low-side switch 103V in the direction opposite to the regenerative current. ) Also decreases by this regenerative current. This means that the exciting current of the low-side switch 103V is attracted by the reactor R. Therefore, the rising period of the V-phase current flowing through the phase coil 100V is shortened to increase the current flowing through the phase coil 100V. Can be increased. In addition, you may provide the reactor R separately for every phase. The operations of the other phase drive circuits are the same as described above.

(Unipolar drive circuit example 2)
An improved circuit of the unipolar type drive circuit 901 that supplies the SRM 902 with a substantially trapezoidal three-phase DC current will be described with reference to FIG. This driving circuit 901 can also be applied to driving a conventional SRM.
This drive circuit 901 has a U-phase drive circuit A, a V-phase drive circuit B, a W-phase drive circuit C, and a reactor R. These phase drive circuits A to C omit the low-side diode 105 and the high-side diode 106 for regeneration described in FIG. 55, but they may be added. Although diodes are employed as the high-side switches 101U, 101V, and 101W, it is obvious that transistors may be used. Reference numeral 107 denotes a high-side diode that connects the high potential end of each phase coil 100U, 100V, 100W and one end of the reactor R. One end of the reactor R and the low potential end 104 of the DC power source are connected by a switch 108. The other end of the reactor R is connected to the low potential end 104 of the DC power source. The other circuit configuration is the same as that of FIG. 5, and the operation of the drive circuit of the other phase is the same as described above.

The operation of this drive circuit will be described.
Magnetic energy is stored in the reactor R by turning on the switch 108 for a predetermined period before the low-side switch 103U is energized. Thereafter, when the switch 108 is turned off, for example, when the low side switch 103U is turned on, the reactor R applies a voltage higher than the high potential end 102 of the DC power supply to the high potential end of the phase coil 100U through the high side diode 107. Thereby, the current of the phase coil 100U rises in a short time, and thereafter, the energization of the phase coil 100U can be performed for a long time. Thereby, torque can be increased. The switch 108 is an acceleration switch and constitutes a so-called chopper circuit together with the reactor R. After the current to the phase coil 100U rises, it is not necessary to apply a high voltage from the reactor R to the phase coil 100U. Therefore, if the phase coil 100U is energized from the high potential end 102 of the DC power source through the high side switch 101U. Good. Thereby, reactor R can be reduced in size. A reactor R may be provided for each phase.

(Unipolar drive circuit example 3)
An improved circuit of the unipolar type drive circuit 901 that supplies the SRM 902 with a substantially trapezoidal three-phase DC current will be described with reference to FIG. This driving circuit 901 can also be applied to driving a conventional SRM.
In this drive circuit 901, only the U-phase drive circuit A, the reactor R, and the switch (acceleration switch) 108 are described for easy understanding. The circuit of FIG. 7 integrates the circuits shown in FIGS. 5 and 6 and also has a common reactor R. In this case, in order to prevent the regenerative current of the phase coil 100U from being short-circuited by the diodes 102 and 107, the MOS switch 109 is employed instead of the high-side diode 107 in FIG. Note that the high-side diode 106 may be replaced with a MOS switch.

  The operation of this drive circuit will be described. The operation of this drive circuit is essentially the same as the operation of the circuits of FIGS. However, simultaneously with turning on the low-side switch 103U, the MOS switch 109 provided in place of the high-side diode 107 is turned on, and the switch (acceleration switch) 108 is turned off. Thereby, a voltage higher than the high potential end 102 of the DC power supply is applied to the U-phase coil 100U by the magnetic energy accumulated in the reactor R, and the excitation current of the phase coil 100U rises more than before. It can be accelerated.

(Unipolar drive circuit example 4)
An improved circuit of the unipolar type drive circuit 904 for supplying a substantially trapezoidal three-phase DC current to the SRM 902 will be described with reference to FIG. This driving circuit 901 can also be applied to driving a conventional SRM.
This drive circuit 901 has a U-phase drive circuit A, a V-phase drive circuit B, and a W-phase drive circuit C. 100U is a U-phase coil, 100V is a V-phase coil, and 100W is a W-phase coil. 103U, 103V, and 103W are low-side switches for PWM control that individually connect the low potential end 104 of the DC power supply and the low potential ends of the phase coils 100U, 100V, and 100W. 110U, 110V, and 110W are backflow prevention diodes that commutate regenerative current between phases. 111U is a U-phase assist coil wound around the stator together with the U-phase coil 100U, 111V is a V-phase assist coil wound around the stator along with the V-phase coil 100U, and 111W is a W-phase phase. This is a W-phase assist coil wound around the stator together with the coil 100W. The connection points P1, P2, P3 of the low potential ends of the phase coils 100U, 100V, 100W and the low side switches 103U, 103V, 103W are individually connected to the high potential ends 102 of the assist coils 111U, 111V, 111W through the diodes 110U, 110V, 110W. It is connected to the. The low potential ends of the assist coils 111U, 111V, and 111W are connected to the low potential end 104 of the DC power supply. However, in this embodiment, for example, as shown in FIG. 10, the rising period of the phase current of one phase is set to overlap the falling period of the phase current of the other one phase.

When the U-phase low-side switch 103U is turned off, a regenerative current due to the magnetic energy of the U-phase phase coil 100U is applied to the assist coil 111U through the diode 110U. As a result, the U-phase current falling period continues for a predetermined period from when the low-side switch 103U is turned off. Almost simultaneously with the turning off of the U-phase low-side switch 103U, the V-phase low-side switch 103V is turned on. As a result, the V-phase current rising period continues for a predetermined period from when the low-side switch 103V is turned on.
In this way, since the regenerative current generated during the U-phase current falling period is energized to the V-phase assist coil 111V during the V-phase current rising period, the V-phase stator magnetic pole is the V-phase coil. In addition to the excitation current of 100V, the current flowing in the V-phase assist coil 111V is further strongly excited. As a result, the rise of the magnetic flux of the V-phase stator magnetic pole can be accelerated.

  Similarly, the W-phase low-side switch 103W is turned on almost simultaneously with the V-phase low-side switch 103V being turned off, and the W-phase assist coil 111W is energized by the magnetic energy of the V-phase coil 100V as described above. Is called. This promotes the rise of the magnetic flux of the W-phase stator magnetic pole. Similarly, the U-phase low-side switch 103U is turned on substantially simultaneously with the W-phase low-side switch 103W being turned off, and the U-phase assist coil 111U is energized by the magnetic energy of the W-phase coil 100W as described above. Is called. This promotes the rise of the magnetic flux of the U-phase stator magnetic pole. It is preferable that the assist coils 111U, 111V, and 111W have a relatively small cross-sectional area and multiple turns compared to the phase coils 100U, 100V, and 100W. In this way, it is possible to reduce the adverse effects of hindering the slot accommodation of the phase coil. In addition, when the regenerative current flows, the assist coil can generate a large counter electromotive force, so the magnitude of the regenerative current of the phase coil can be reduced and the current fall period of the phase coil can be shortened. Can do.

  The motor drive circuit of this embodiment has an advantage that the cost and loss of the motor drive circuit can be reduced because it is only necessary to add the diodes 110U, 110V, 110W in addition to the low-side switches 103U, 103V, 103W. Further, the regenerative current does not flow from the assist coil to the low-side switch of the next phase, and the loss and heat generation of the low-side switch of the next phase can be reduced. In FIG. 8, Im is an exciting current of the phase coil 100, and Ir is a regenerative current.

(Modification)
The axially extending segment SRM in FIG. 2 extends the stator segment 3 having the stator magnetic poles 31 to 34 in the axial direction. As a result, the stator magnetic poles 31 to 34 are arranged at equal positions in the circumferential direction, and the rotor segments 7U, 7V, 7W have circumferential positions different from each other in the circumferential direction by an electrical angle (2/3) π. Instead, the rotor segments 7U, 7V, and 7W are integrated and extended in the axial direction, and a pair of U-phase stator poles 31 and 32 (U-phase pole pair) and a pair of V-phase stator poles 32 and 33 are combined. The (V-phase magnetic pole pair) and the pair of W-phase stator magnetic poles 33 and 34 (W-phase magnetic pole pair) may be shifted in the circumferential direction by an electrical angle (2/3) π. This aspect is suitable when the magnetic pole pairs of each phase are manufactured separately. In addition, the magnetic pole pair of each phase may be shifted in the circumferential direction, and the rotor segments 7U, 7V, and 7W may be shifted in the circumferential direction.

(Example 2)
The structure and control of the axially extending segment SRM of the present invention will be described with reference to the second embodiment. A schematic axial view of the SRM 902 of this example is shown in FIG. The SRM 902 is characterized in that ring coils 40A, 40B, and 40C through which a direct current flows are added to the SRM 902 of the first embodiment shown in FIG. The operation of this SRM 902 will be described with reference to FIG. FIG. 10 is a timing chart showing waveforms of the inductance and phase current of the SRM 902. The inductance waveform of this SRM 902 is the same as that of the SRM 902 of the first embodiment shown in FIG. That is, the shape and arrangement of the stator magnetic poles 31 to 34 and the rotor segments 7U, 7V, and 7W of the SRM 902 of the second embodiment are the same as those in FIG.

Briefly, this embodiment divides the three-phase currents Iu, Iv, Iw of the SRM 902 of the first embodiment shown in FIG. 3 into its alternating current component and its direct current component, thereby dividing the three-phase alternating current (Iuac, Ivac, Iwac) is applied to the ring coils 4U, 4V, and 4W, and a direct current Idc is applied to the ring coils 40A, 40B, and 40C.
The direction of the DC magnetic field generated in the stator magnetic pole 32 by the U-phase DC current Idc flowing in the U-phase ring coil 40A is the same as the direction of the DC magnetic field generated in the stator magnetic pole 32 by the V-phase DC current Idc flowing in the V-phase ring coil 40B. The The direction of the DC magnetic field generated in the stator magnetic pole 33 by the V-phase DC current Idc flowing in the V-phase ring coil 40B is the same as the direction of the DC magnetic field generated in the stator magnetic pole 33 by the W-phase DC current Idc flowing in the W-phase ring coil 40C. The

  The direction of the AC magnetic field generated in the stator magnetic poles 31 and 32 by the U-phase ring coil 4U during the inductance increase period Ti is the same as the direction of the DC magnetic field generated in the stator magnetic poles 31 and 32 by the U-phase DC current Idc flowing in the U-phase ring coil 40A. It is said. The direction of the AC magnetic field generated in the stator magnetic poles 32 and 33 by the V-phase ring coil 4V during the inductance increase period Ti is the same as the direction of the DC magnetic field generated in the stator magnetic poles 32 and 33 by the V-phase DC current Idc flowing in the V-phase ring coil 40B. It is said. The direction of the AC magnetic field generated in the stator magnetic poles 33 and 34 by the W-phase ring coil 4W during the inductance increase period Ti is the same as the direction of the DC magnetic field generated in the stator magnetic poles 33 and 34 by the W-phase DC current Idc flowing in the W-phase ring coil 40C. It is said.

  In this way, the magnetic field formed by the three-phase alternating current (Iuac, Ivac, Iwac) flowing through the ring coils 4U, 4V, 4W and the direct current Idc flowing through the ring coils 40A, 40B, 40C is shown in FIG. It becomes equal to the magnetic field formed by the three-phase currents Iu, Iv, and Iw of Example 1 shown. Since the formed magnetic field waveforms are the same, the SRM of this embodiment can perform the same operation as the SRM of the first embodiment. In FIG. 10, the solid lines of the three-phase alternating current (Iuac, Ivac, Iwac) and the direct current Idc indicate current waveforms when a large current is applied, and the broken lines indicate current waveforms when a small current is applied. However, the direct currents Idc and Idc ′ in FIG. 10 are described under the condition that the number of turns of the ring coils 4U, 4V, and 4W and the ring coils 40A, 40B, and 40C is equal. Actually, the amplitude of the direct current Idc is small by the number of turns. The zero value of the three-phase alternating current (Iuac, Ivac, Iwac) is set at the midpoint of the bottom period Tb and the midpoint of the peak period Tp.

  What is important in this embodiment is that the forming magnetic field (ampere turn) of the DC coil is substantially equal to the forming magnetic field (ampere turn) of the three-phase alternating current (Iuac, Ivac, Iwac) in the inductance increasing period Ti (90% or more). Is equal). Thereby, in the inductance reduction period Td, the magnetic field for forming the three-phase alternating current (Iuac, Ivac, Iwac) is canceled by the magnetic field for forming the direct current Idc. That is, the combined magnetic field that acts on the rotor segments 7U, 7V, and 7W during the inductance reduction period Td is substantially zero, and no reverse reluctance torque is generated. This reduces torque reduction and torque ripple and reduces magnetic noise and vibration.

The number of turns of the ring coils 40A, 40B, and 40C, which are DC coils, is significantly increased than that of the ring coils 4U, 4V, and 4W, and the conductor cross-sectional areas of the ring coils 40A, 40B, and 40C are the ring coils 4U, 4V, and 4W. Will be significantly smaller than that. Thereby, the copper loss of ring coil 40A, 40B, 40C can be reduced.
To explain further, it seems useless to pass reverse currents to two ring coils in the same slot in the inductance reduction period Td. However, the copper loss is greatly reduced due to the significant increase in the number of turns of the ring coils 40A, 40B, and 40C. When the coil is accommodated in the same slot cross section assuming that the slot space factor is 100%, the formed magnetic field is proportional to the number of turns.
Furthermore, since two types of currents (for example, Iuac and Idc) flowing through two ring coils (for example, 40A and 4U) in the same slot are one current when viewed from the rotor segment 7U, the number of turns of these two ring coils is determined. Assuming that they are equal, the motor torque T is proportional to the square value of (Iuac and Idc).

(Motor drive circuit)
The configuration of the motor drive circuit of this embodiment is shown in FIG. 21 is a rotor rotation angle detection circuit, 22 is a sine wave oscillation circuit, 23 is a direct current control transistor, 24 and 25 are capacitors, 26 is a flywheel diode, 27 is a current detection resistor, and 28 is a base current limiting resistor. . The capacitor 24 and the flywheel diode 26 are connected in parallel with the ring coils 40A, 40B, and 40C connected in series. The current detection resistor 27 detects a voltage drop due to the emitter current of the transistor 34 and sends it to the motor controller 903.
The drive circuit 901 includes three H bridge circuits (single phase full frame bridge circuits) that supply single phase alternating currents to the three phase ring coils 4U, 4V, and 4W independently. A known H-bridge circuit has four switching transistors.

  The DC current Idc supplied to the ring coils 40A, 40B, and 40C connected in series is PWM-controlled by the transistor 23. Capacitor 24 absorbs switching noise of transistor 23 and also absorbs fluctuations in the total induced voltage of ring coils 40A, 40B, and 40C due to movement of rotor segments 7U, 7V, and 7W. That is, in this embodiment, the ring coils 4U, 4V, and 4W and the ring coils 40A, 40B, and 40C are magnetically coupled in a period in which the rotor segments 7U, 7V, and 7W sequentially face the stator magnetic poles 31 to 34, An alternating voltage is sequentially induced in the ring coils 40A, 40B, and 40C. Since the influence of the AC voltage is absorbed by the capacitor 24, the adverse effect on the DC power supply 900 can be reduced.

  Further, in this embodiment, the PWM duty ratio of the transistor 23 is feedback controlled based on the DC current Idc detected by the current detection resistor 27, and the DC current Idc is set to a command value, that is, a three-phase AC current (Iuac, Ivac, Iwac). It is adjusted to a value substantially equal to the amplitude of the inductance reduction period Td. Strictly speaking, the DC magnetic field generated by the DC current Idc and the AC magnetic field generated by the three-phase AC current (Iuac, Ivac, Iwac) in the inductance reduction period Td are made substantially equal.

This will be described more specifically.
After amplifying the voltage drop of the current detection resistor 27, the motor controller 903 removes the harmonic component and detects the direct current Idc and the low frequency voltage (inductive voltage). The transistor 23 is PWM-controlled so that the difference between the detected current and the command value of the DC current Idc becomes zero, and the current flowing through the ring coils 40A, 40B, and 40C is controlled to the command value of the DC current Idc. Thereby, it is possible to prevent the direct current Idc flowing through the ring coils 40A, 40B, and 40C from fluctuating due to the movement of the rotor segments 7U, 7V, and 7W and the change of the three-phase alternating current (Iuac, Ivac, Iwac).
The sine wave oscillation circuit 22 applies a sine wave voltage of about 100 kHz to a connection point between the ring coils 40A and 40B through a DC cut capacitor 25. The sine wave voltage may be applied to a connection point between the ring coil 40C and the transistor 23, or may be applied to a connection point between the capacitor 24 and the ring coil 40A. Instead of the sine wave voltage, a high frequency voltage having another waveform or frequency may be used. The voltage drops of the ring coils 40A, 40B, and 40C are input to the rotor rotation angle detection circuit 21.

The rotor rotation angle detection circuit 21 extracts a band including a sine wave voltage component of the input voltage drop of each of the ring coils 40A, 40B, 40C, and rectifies it to form a rotation angle signal. This rotation angle signal is substantially proportional to the inductances of the ring coils 40A, 40B, and 40C that change according to the rotor rotation angle as described above. The rotor rotation angle detection circuit 21 estimates the rotor rotation angle based on the inductance change waveform of each phase and outputs it to the motor controller 903. The rotor rotation angle detection circuit 21 can detect the rotor rotation angle even when the rotor is stationary.
(Torque control)
Control of the motor torque performed by the motor controller 903 will be described with reference to FIG. First, the rotational speed command Ns and the torque command Ts are read from the outside, and the rotor rotational angle θ, the three-phase alternating current (Iuac, Ivac, Iwac), and the direct current Idc are read from the rotor rotational angle detection circuit 21 and the current detection circuit (S100). ).
Next, based on the read torque command Ts, the amplitude of the trapezoidal three-phase currents Iu, Iv, Iw energized to the ring coils 4U, 4V, 4W is calculated, and the three-phase currents Iu, Iv, Iw are divided. Thus, the command values of the three-phase alternating current (Iuac, Ivac, Iwac) and the direct current Idc are calculated (S102). Next, feedback control is performed so that the detected values of the three-phase alternating current (Iuac, Ivac, Iwac) and the direct current Idc are equal to the command value. In order to calculate the command values of the three-phase currents Iu, Iv, and Iw from the torque command value Ts, it is necessary to obtain the inductance increase rate dL / dθ. The calculation of the inductance increase rate dL / dθ is performed in the first embodiment. What is necessary is just to obtain | require by the method similar to.

(effect)
According to this embodiment, the stator magnetic poles 31 to 34 are strongly excited by both the three-phase alternating currents (Iuac, Ivac, Iwac) and the direct current Idc during the inductance increase period, so that a strong reluctance torque can be generated. . Further, in order to adjust the direct current Idc flowing through the ring coils 40A, 40B, and 40C to be equal to the amplitude of the three-phase alternating current (Iuac, Ivac, Iwac), generation of reverse reluctance torque (power generation torque) during the inductance reduction period Td is performed. It can be almost zero. Further, by controlling the direct current Idc flowing through the ring coils 40A, 40B, and 40C, the three-phase generated voltage generated in the ring coils 4U, 4V, and 4W can be easily adjusted. In addition, by applying a high frequency voltage to a DC coil (that is, the ring coils 40A, 40B, and 40C) for forming a DC magnetic flux in the SRM 902, the technical idea of detecting the rotor rotation angle using the inductance change is as follows: It was not known before.

(Example 3)
The structure and control of the axially extending segment SRM of the present invention will be described with reference to the third embodiment. The structure of the SRM 902 will be described with reference to FIG. FIG. 13B is a schematic diagram showing one of a plurality of stator segments constituting the stator core of the SRM 902. FIG. 13A shows the stator magnetic poles belonging to the two stator segments, the rotor segments of the respective phases, It is the circumferential direction expanded view which shows these positional relationships. This SRM is obtained by changing the circumferential width of the stator magnetic poles 31 to 34 from the electrical angle π to the electrical angle 2π / 3 in the SRM 902 of the first and second embodiments shown in FIG. Each slot accommodates ring coils 40A, 40B, and 40C that are DC coils, as well as ring coils 4A to 4C that are AC coils, as in the second embodiment.

The operation of this SRM 902 will be described with reference to FIG. FIG. 14 is a timing chart showing waveforms of inductance and phase current of the SRM 902. The inductance waveform of the SRM 902 has a substantially zero peak period because the circumferential width of the stator magnetic poles 31 to 34 is shortened.
The three-phase currents Iu, Iv, and Iw are + currents during a period of approximately π / 3, and are negative currents during the remaining period of approximately 2π / 3. However, the magnitude of the minus current of the three-phase currents Iu, Iv, and Iw is half of the magnitude of the plus current. The direct current Idc is substantially equal to the magnitude of the minus current of the three-phase currents Iu, Iv, Iw. However, in FIG. 13, the number of turns of the DC coil is considered to be equal to the number of turns of the AC coil. As a result, excitation of the stator magnetic poles 31 to 34 during the period other than the inductance increase period is canceled.

The three-phase currents Iu, Iv, and Iw having the waveforms shown in FIG. 14 operate the three-phase inverter 21 that feeds the three-phase star-connected ring coils 4A to 4C as shown in FIG. be able to. That is, in the period t0-t1, the V-phase upper arm element VH, the U-phase lower arm element UL, and the W-phase lower arm element WL are turned on. In a period t1-t2, the W-phase upper arm element WH, the U-phase lower arm element UL, and the V-phase lower arm element VL are turned on. In the period t2-t3, the U-phase upper arm element UH, the V-phase lower arm element VL, and the W-phase lower arm element WL are turned on. In this way, the ring coils 4 </ b> A to 4 </ b> C are energized with a current that is half the current during the inductance increase period during a period other than the inductance increase period.
Actually, the number of turns of the ring coils 40A, 40B, and 40C that are DC coils is K times the number of turns of the ring coils 4A, 4B, and 4C that are AC coils, and the ring coils 40A, 40B, and 40C are energized. The direct current Idc is set to 1 / 2K of the current during the inductance increase period of the ring coils 4A to 4C. According to this embodiment, the number of power switching elements of the motor drive circuit can be halved.

(Modification 1)
In the first and second embodiments, instead of the ring coils 40 </ b> A, 40 </ b> B, 40 </ b> C, a DC coil through which a direct current Idc flows is concentrated around the group of stator magnetic poles 32 and concentrated around the magnetic pole group of the stator magnetic poles 33. Good.
(Modification 2)
In the first and second embodiments, the motor controller 903 can have a high efficiency operation mode and a large torque operation mode. In the high-efficiency operation mode, the ampere turns of the ring coils 4U, 4V, and 4W and the ampere turns of the ring coils 40A, 40B, and 40C are made substantially equal (equal to 90% or more) during the inductance reduction period Td. Thereby, the reverse reluctance torque during the inductance reduction period Td can be substantially canceled.
In the large torque operation mode, the ampere turn of the ring coils 4U, 4V, and 4W is made 10 to 50% larger than the ampere turn of the ring coils 40A, 40B, and 40C in the inductance reduction period Td. In this way, reverse torque is generated in the periods Tc and Td. However, the positive torque during the inductance increase period Ti is the sum of the ampere turns of the ring coils 40A, 40B, and 40C and the ampere turns of the ring coils 4U, 4V, and 4W. Can do.

(Modification 3)
In the first and second embodiments, permanent magnets may be provided on the stator magnetic poles 31 to 34 in order to reduce the direct current Idc.
(Modification 4)
Of course, the number of phases of the three-phase axially extending segment SRM described in the first to third embodiments may be changed. For example, FIGS. 16 and 17 show a two-phase double coil type SRM. In FIG. 16, If is a direct current Idc energized to the DC coil 40 concentratedly wound around the stator magnetic pole 32 or constituted by a ring coil. Reference numeral 4A denotes a ring coil that passes through a slot between the stator magnetic poles 31 and 32. A ring coil 4B passes through a slot between the stator magnetic poles 3 and 33. The rotor segment 7 faces the stator magnetic poles 31 and 32, and the rotor segment 8 faces the stator magnetic poles 31 and 32. The rotor segments 7 and 8 are arranged at an electrical angle π as shown in FIG. The ring coils 4A and 4B are supplied with an alternating current I having an opposite phase. FIG. 17 shows the circumferential positional relationship between the stator poles 31 to 33 of the SRM of FIG. 17A shows the state of the rotor electrical angle 0, and FIG. 17B shows the state of the rotor electrical angle π.

(Modification 5)
Of course, the number of stator magnetic poles of the stator segment 3 described in the first and second embodiments may be changed. For example, FIG. 18 shows a stator segment 3 having seven stator magnetic poles 31-37. The rotor segments 7U, 7V, and 7W are arranged with an electrical angle of 2π / 3. The rotor segments 8U, 8V, 8W are arranged with an electrical angle of 2π / 3. The rotor segments 7U, 8U are arranged with an electrical angle π shifted. The order of the three-phase currents (Iu, Iv, Iw) energized in the ring coils 4A, 4B, 4C, 4D, 4E, 4F may be changed as shown in FIG.

  Further, in FIGS. 18 and 19, instead of energizing the three-phase currents (Iu, Iv, Iw) to the ring coils 40A, 40B, 40C, 4D, 4E, 4F, the DC current Idc is energized in each of the seven slots. And a ring coil to which an alternating current of one phase is energized may be accommodated. Further, instead of the ring coil through which the direct current Idc is energized, a DC coil in which the direct current Idc flows through the stator magnetic poles 32 to 36 may be concentratedly wound.

Example 4
A fourth embodiment of the axially extending segment SRM of the present invention will be described with reference to FIGS. FIG. 20A is a schematic axial sectional half view of this three-phase ring coil SRM. FIG. 20 (B) is a circumferential partial development view of the stator segments (hereinafter also simply referred to as segments) 3A to 3C of FIG. 20 (A). FIG. 21 is a schematic radial side view of the SRM of FIG. However, a part of the code | symbol used in this Example is unrelated to the code | symbol of Example 1-3. This ring coil SRM is characterized in that a part of the V and W phase ring coils is disposed radially inward from the rotor segment.
1 is a stator, 2 is a rotor, 3A to 3E are stator segments, 4A to 4E and 9A to 9E are ring coils forming an armature coil, 5A is a front housing, and 5B is a rear housing. The rotor 2 has a nonmagnetic boss 6 and a rotor segment 7. 8 is a rotating shaft.

The segments 3A to 3E form a stator core. The segments 3A to 3C are fixed to the inner peripheral surfaces of the front housing 5A and the rear housing 5B. The segment 3D is fixed to the inner end wall of the front housing 5A, and the segment 3E is fixed to the inner end wall of the rear housing 5B. The segments 3A to 3E are arranged at a constant pitch in the circumferential direction. The segments 3A to 3E are respectively produced by laminating soft magnetic steel plates in a substantially circumferential direction (tangential direction). The segments 3A to 3E and the rotor segment 7 extend in the axial direction. A large number of rotor segments 7 are arranged in the circumferential direction at an electrical angle π pitch on the outer peripheral surface of the boss portion 6.
FIG. 20B is a partial schematic development view showing the circumferential positions of the segments 3A to 3C. The segments 3A and 3D are arranged at the same position in the circumferential direction. The segments 3C and 3E are also arranged at the same position in the circumferential direction. The segments 3A, 3D, 3C, 3E are formed in a C shape. The segment 3B is formed in an E shape.

The segments 3A and 3D are arranged so as to be shifted in the circumferential direction by an electrical angle of 2π / 3 with respect to the segment 3B. The segment 3B is shifted from the segments 3D and 3E by an electrical angle of 2π / 3 in the circumferential direction. The ring coils 4A to 4E are AC coils through which an alternating current flows, and the ring coils 9A to 9E are DC coils. The ring coils 4A to 4E and 9A to 9E are wound around the rotor 2 in a ring shape.
The ring coils 4A and 9A are accommodated in the slots of the segment 3A, and the two pairs of ring coils 4B and 9B are accommodated in the two slots of the segment 3B. However, the current directions of the two V-phase ring coils 4B accommodated in the two slots are opposite, and the current directions of the two DC ring coils 9B accommodated in the two slots are opposite. The ring coils 4C and 9C are accommodated in the slots of the segment 3C, the ring coils 4D and 9D are accommodated in the slots of the segment 3D, and the ring coils 4E and 9E are accommodated in the slots of the segment 3E.

The current directions of the U-phase ring coils 4A and 4D are the same, and the current directions of the U-phase ring coils 9A and 9D are the same. The current directions of the W-phase ring coils 4C and 4E are the same, and the current directions of the W-phase ring coils 9C and 9E are the same.
The rotor segments 7 are arranged in the circumferential direction at an electrical angle of 2π pitch. The rotor segment 7 extends in the axial direction. In this embodiment, the circumferential width of the rotor segment 7 and the circumferential width of the segments 3A to 3E are substantially equal to the electrical angle π. May be 2π / 3, and the other may be π.

The rotor segment 7 is fixed to the outer peripheral surface of the boss portion 6 made of a nonmagnetic metal. The segments 3A to 3E and the rotor segment 7 are produced by laminating soft magnetic steel plates in a substantially circumferential direction (tangential direction). The rotor segment 7 protrudes from the boss portion 6 on both sides in the axial direction. The front end portion of the rotor segment 7 is inserted between the segments 3A and 3D, and the rear end portion of the rotor segment 7 is inserted between the segments 3C and 3E. The boss 6 is fitted and fixed to the rotary shaft 8. The rotating shaft 8 is rotatably supported by the front housing 5A and the rear housing 5B.
A direct current is applied to the ring coils 9A to 9E connected in series. This direct current is adjusted by PWM control of the current control transistor. Three-phase alternating currents (Iuac, Ivac, Iwac) that are passed through the ring coils 4A to 4E, which are alternating current windings (AC coils), are formed by full-bridge inverters for each phase or by one three-phase inverter.

  As described above, in the preferred operation mode, the ampere turns of the ring coils 4A to 4E in the inductance reduction period Td are substantially equal to the ampere turns of the ring coils 9A to 9E, and their directions are opposite. Thereby, the segments 3A to 3E generate almost no magnetic flux during the inductance reduction period Td. In the inductance increase period Ti, the ampere turns of the ring coils 4A to 4E and the ampere turns of the ring coils 9A to 9E are in the same direction and have the same magnitude, so that a strong magnetic flux is generated. The current phases of the ring coils 4A and 4D are shifted from the current phase of the ring coil 4B by an electrical angle of 2π / 3. Similarly, the current phase of the ring coil 4B is shifted by an electrical angle of 2π / 3 with respect to the current phases of the ring coils 4C and 4E. Thereby, the electric operation of the three-phase segment type SRM becomes possible. Power generation is performed in the same way. During power generation, the ampere turns of the ring coils 4A to 4E are substantially equal to the ampere turns of the ring coils 9A to 9E, and the directions thereof are opposite. Accordingly, the segments 3A to 3E generate almost no magnetic flux during the inductance increase period Ti.

The axial width of the segment 3B is adjusted so that the average torque generated by the segments 3A and 3D is equal to the average torque generated by the torque generated by the segment 3B. The axial widths of the segments 3C and 3E are adjusted so that the average torque generated by the segments 3C and 3E is equal to the average torque generated by the torque generated by the segment 3B.
According to this embodiment, the axial length of the motor can be shortened compared to the case where the segments 3D and 3E are arranged on the radially outer side of the rotor 3, and the motor can be greatly reduced in size and weight. Moreover, since the axial protrusion length of the rotor segment 7 can be shortened, high-speed rotation is possible. Moreover, a direct current can be superimposed on the ring coils 4A to 4E for the power generation operation.
100g is a small gap provided between the segments 3A and 3B and between the segments 3B and 3D. The small gap 100g prevents circumferential magnetic leakage between the segments 3A and 3B and circumferential magnetic leakage between the segments 3B and 3C, similarly to the small gap g shown in FIG. Thereby, the iron loss and eddy current loss of the stator segment which consists of a circumferential direction (tangential direction) laminated steel plate can be reduced.

  FIG. 6 is a schematic side view of an SRM (double coil type SRM having a ring coil and a stator segment and an axially extending rotor segment) of this embodiment in which six stator segments and six rotor segments are arranged in the circumferential direction. 21. However, the front housing 5A, the segments 3A, 3D, and the ring coils 4A, 9A, 4D, 9D are removed. Reference numeral 10 denotes a nonmagnetic comb-like member inserted between two stator segments adjacent in the circumferential direction. Each tooth of two comb-like members 10 each formed in a cylindrical shape is inserted between each stator segment from both axial sides of each stator segment. Thereby, the vibration of the stator segment is suppressed. In addition, the ring coil is protected.

(Modification)
In this embodiment, in addition to the ring coils 4A to 4E that are AC coils, ring coils 9A to 9E that are DC coils are used in combination to form a double coil SRM, but the ring coils 9A to 9E that are DC coils are omitted. Then, a trapezoidal direct current may be applied to the ring coils 4A to 4E.
In addition, a normal magnet synchronous motor may be provided by providing a permanent magnet in the rotor segment, or a DC coil may be omitted by providing a permanent magnet in the stator segment. Further, the circumferentially extending segment RM of each embodiment described above or a conventionally known RM can be applied to the axially extending segment RM of this embodiment.

(Example 5)
A fifth embodiment of the axially extending segment SRM of the present invention will be described with reference to FIGS. FIG. 22 is a schematic partial sectional view in the axial direction of the three-phase axially extending segment RM of the outer rotor structure constituting the in-wheel motor. Six rotor segments 7 are fixed to the inner peripheral surface of the peripheral wall of the nonmagnetic wheel 60 at a pitch of 30 degrees in the circumferential direction. Six stator segments 3 are fixed to the outer peripheral surface of a nonmagnetic disk 50 that is fixed to a stationary shaft (not shown) and extends radially outward at a pitch of 30 degrees in the circumferential direction. At the radial position of the gap between the stator segment 3 and the rotor segment 7, the circumferential width of the stator segment 3 and the rotor segment 7 is about 15 degrees. The rotor segment 7 and the stator segment 3 extend in the axial direction.

  The stator segment 3 is provided with six slots 30 in the axial direction. Each slot 30 accommodates two three-phase ring coils U, V, and W. The ring coils U, V, W are formed in a ring shape around the stationary axis. Each slot 30 accommodates a ring coil 9 which is a DC coil. The stator segment 3 and the rotor segment 7 are configured by laminating a number of electromagnetic steel plates having a thickness of 0.3 mm in the tangential direction. The rotor segment 7 is formed using a grain-oriented electrical steel sheet whose axial direction is the magnetization facilitating direction. The outer peripheral edge of the electromagnetic steel sheet forming the stator segment 3 and the inner peripheral edge of the electromagnetic steel sheet forming the rotor segment 7 are formed in a substantially arc shape (see FIG. 23).

The layout of the three-phase ring coils U, V, W is shown in FIG. The ring coil 9 that is a DC coil is disposed in the vicinity of the opening 90 of the slot 30, and the ring coils U, V, and W that are AC coils are disposed on the bottom side of the slot 30. The ring coil 9, which is a DC coil, is formed with a small diameter and wound with many turns. Therefore, even when the tips of the stator magnetic poles 4A to 4G of the stator segment 3 have a flange that protrudes in the axial direction and narrows the opening of the slot 30, many turns of the ring coil 9 are adjacent to the flange. Can be arranged.
One rotor segment 7 is arranged by adjoining a plurality of small segments having different lengths in the circumferential direction (see FIG. 22). Each small segment has a width of 5 degrees (refers to 5 °) in the circumferential direction when the circumferential width of the rotor segment 7 and the stator magnetic poles 4A to 4G is 15 degrees. Each small segment is formed by laminating a number of electromagnetic steel plates in the tangential direction, as in the segments of the other embodiments. A small gap g (see FIG. 2) is provided between each small segment to prevent circumferential magnetic leakage between the small segments. In this embodiment, since the stator segment 3 extends in the axial direction, each small segment of the rotor segment 7 is arranged with an electrical angle of 2π / 3 in the circumferential direction for each phase. According to this embodiment, in the axially extending segment RM having 6 slots in the axial direction, the ring coils are arranged in the order of U, V, W, U, V, and W, so that the concentration of magnetic flux can be reduced. it can.

(Example 6)
A sixth embodiment of the axially extending segment SRM according to the present invention will be described with reference to FIGS. This embodiment shows an example of a suitable winding method for a ring coil employed in a radial gap type axially extending segment RM.
As shown in FIG. 24, the ring coil 40 constituting the AC coil is formed by spirally winding an insulating coated copper plate in the axial direction. The diameter of each turn of the ring coil 40 is equal. Both end portions 40A and 40B of the ring coil 40 are bent outward in the radial direction. In the outer rotor structure, both end portions 40A and 40B of the ring coil 40 are bent inward in the radial direction. Note that both end portions 40A and 40B of the ring coil 40 may be bent in the radial direction.

A method of accommodating the ring coil 40 in the slot 30 of the stator segment 3 extending in the axial direction will be described with reference to FIG. 4A and 4B are stator magnetic poles of the stator segment 3 extending in the axial direction. Reference numeral 30 denotes a slot between the stator magnetic poles 4A and 4B. AX indicates the axial direction, and RA indicates the radial direction. Reference numeral 400 denotes a flange portion of the stator magnetic poles 4A and 4B, and 401 denotes a slot opening between the stator magnetic poles 4A and 4B.
First, half ring coils 40C and 40D having half the number of turns of the ring coil 40 are prepared. Half ring coils 40C and 40D are constituted by an insulation covering copper plate. Next, the diameter of the half ring coil 40C is reduced by tightening. In this embodiment, the half ring coil 40C is reduced in order to explain the case where the ring coil 40 is wound around the stator segment 3 of the inner rotor type ring coil SRM, but the ring coil is added to the stator segment 3 of the outer rotor type ring coil SRM. In the case of winding 40, the half ring coil 40C is loosened and its diameter is expanded.

  Next, the reduced diameter half-ring coil 40C is inserted in the axial direction on the radially inner side of a stator core formed by arranging a large number of stator segments 3 at a predetermined circumferential pitch. Next, each turn of the half ring coil 40C is inserted into the slot opening 401 sequentially from one end thereof, and the half ring coil 40C is rewound. Thereby, each turn of the half ring coil 40 </ b> C is expanded in diameter and accommodated in the slot 30. Next, each turn accommodated in the slot 30 is moved in the axial direction to be brought into close contact with the stator magnetic pole 4A. Thereby, the half ring coil 40C is accommodated in the half of the slot 30 on the stator magnetic pole 4A side. By the same operation, the half ring coil 40D is accommodated in the half of the slot 30 on the stator magnetic pole 4B side. Finally, the ring coil 40 is completed by connecting in series with the half ring coils 40C and 40D.

  In this way, the ring coil 40 of the radial gap type axially extending segment RM can be accommodated in the slot 30 with a high slot space factor by a simple process. Further, the ring coil 40 having a spiral copper plate shape has excellent thermal conductivity. This ring coil 40 is suitable as an AC coil of the axially extending segment RM. The ring coil winding method of this ring coil SRM can be employed in various types of motors using a ring coil.

(Example 7)
An example of a ring coil winding method employed in the axial gap type radially extending segment RM will be described with reference to FIG. In this embodiment, the ring coil constituting the AC coil is configured by spirally winding an insulating coated copper plate in the radial direction. The width of each turn of the ring coil is equal. Both ends of the ring coil are bent toward the opposite side of the rotor in the axial direction. The stator segment 3 and the rotor segment of this axial gap motor extend in the radial direction. The stator magnetic poles 4A and 4B of the stator segment 3 are adjacent to each other in the radial direction with the slot 30 interposed therebetween. 401 is a slot opening between the stator magnetic poles 4A and 4B. The slot opening 401 opens toward one side in the axial direction. AX indicates the axial direction, and RA indicates the radial direction.
A method of accommodating the ring coil in the slot 30 of the stator segment 3 extending in the radial direction will be described with reference to FIG.

First, half ring coils 40C and 40D having half the number of turns of the ring coil are prepared. The half ring coils 40C and 40D are configured by spirally winding an insulation-coated copper plate having a constant width in a drum shape. Reference numeral 500 denotes a half ring coil 40 </ b> C that is wound around a drum and is not accommodated in a slot. The outer diameters of the ring coils 40 </ b> C and 40 </ b> D are equal to the diameter from the rotation axis M to the slot opening 401.
Next, the half-ring coil 40 </ b> C is rotated and pulled out in the axial direction and inserted into the slot 30. Thereby, the half ring coil 40C is spirally wound in the radial direction into the slot 30 in order from the outer peripheral portion thereof. Each turn of the half ring coil 40C accommodated in the slot 30 is sequentially tightened radially inward. The stator segment 3 may be rotated. Thereby, the half ring coil 40C is accommodated in the half of the slot 30 on the stator magnetic pole 4A side. By the same operation, the half ring coil 40D is accommodated in the half of the slot 30 on the stator magnetic pole 4B side. Finally, the ring coils are completed by connecting the half ring coils 40C and 40D in series.

  In this way, the ring coil of the axial gap type radially extending segment RM can be accommodated in the slot 30 with a high slot space factor by a simple process. A ring coil having a spiral copper plate shape has excellent thermal conductivity. This ring coil is suitable as an AC coil of the axially extending segment RM. The ring coil winding method of the ring coil SRM can be employed in various types of axial gap motors using a ring coil.

(Example 8)
An SRM according to the eighth embodiment will be described with reference to FIG. In this embodiment, when the stator segment or the rotor segment of the axially extending segment SRM is composed of the soft magnetic steel plates laminated in the circumferential direction, each soft magnetic steel plate is separated from the central portion in the circumferential direction (tangential direction) of the segment. It is characterized in that the radial end faces of the soft magnetic steel plates are arranged in a substantially circular shape by shifting in a substantially radial direction (more precisely, a direction perpendicular to the tangential direction).

  300 is a steel plate constituting the segment 7 of the rotor 2, and 400 is a steel plate constituting the stator magnetic pole 31. A total of ten steel plates 300 are formed in the same shape, and a total of ten steel plates 400 are formed in the same shape. Actually, the circumferential direction (tangential direction) of one segment is formed by laminating 100 or more soft magnetic steel plates. The steel plates 300 and 400 are arranged at substantially the same position in the radial direction at the circumferential center portions of the segments 7 and 31, and are relatively in the direction approaching the circular electromagnetic gap G in the radial direction at both circumferential ends of the segments 7 and 31. It is greatly shifted to. By arranging the steel plates 300 and 400 in this way, the width of the electromagnetic gap G between the segment 7 of the rotor 2 and the stator magnetic pole 31 can be made substantially equal using the steel plates 300 and 400 having the same shape.

Example 9
The SRM of the ninth embodiment will be described with reference to FIG. In this embodiment, a structure in which the stator segment or the rotor segment of the axially extending segment SRM is suitably formed from a circumferentially laminated soft magnetic steel sheet will be described.
FIG. 28A is a schematic explanatory diagram in which a part of the stator segment 3A and the rotor segment 7 described so far are enlarged. The stator segment 3A is formed by laminating electromagnetic steel plates 2000 in the circumferential direction (tangential direction). The rotor segment 7 is formed by laminating electromagnetic steel sheets 2001 in the circumferential direction (tangential direction). G is an electromagnetic gap (for example, 0.7 mm) between the stator segment 3A and the rotor segment 7. In FIG. 28A, the front end portion of the stator segment 3A and the rear end portion of the rotor segment 7 face each other with the electromagnetic gap G interposed therebetween. The magnetic flux Φ is concentrated on the electromagnetic steel plate 2000 at the front end portion of the stator segment 3A and the electromagnetic steel plate 2001 at the rear end portion of the rotor segment 7. Therefore, the magnetic flux Φ entering the stator segment 3A flows in the circumferential direction (tangential direction) to the electromagnetic steel plate 2000 in the circumferential direction front. As a result, a large eddy current loss occurs in the electromagnetic steel sheet 2000. The same eddy current loss occurs in each electromagnetic steel sheet 2001 of the rotor segment 7.

  FIG. 28B is a schematic explanatory diagram in which a part of the stator segment 3A and the rotor segment 7 of this embodiment is enlarged. The stator segment 3A is formed by laminating electromagnetic steel plates 2000 in the circumferential direction (tangential direction). The rotor segment 7 is formed by laminating electromagnetic steel sheets 2001 in the circumferential direction (tangential direction). G is an electromagnetic gap (for example, 0.7 mm) between the stator segment 3A and the rotor segment 7. In FIG. 28B, the front end portion of the stator segment 3A and the rear end portion of the rotor segment 7 face each other with the electromagnetic gap G interposed therebetween. The magnetic flux Φ is concentrated on the electromagnetic steel plate 2000 at the front end portion of the stator segment 3A and the electromagnetic steel plate 2001 at the rear end portion of the rotor segment 7. However, in this embodiment, a thin nonmagnetic layer 200 </ b> A is formed between the electromagnetic steel plates 2000 and between the electromagnetic steel plates 2001. In this embodiment, the nonmagnetic layer 200A has a thickness of 10 to 50% (for example, about 0.05 to 1 mm) of the electromagnetic steel sheet, and is formed by coating with an insulating resin. The magnetic resistance of one electromagnetic steel sheet 2000 positioned at the rear end of the stator segment 3A and the magnetic resistance of one electromagnetic steel sheet 2001 positioned at the front end of the rotor segment 7 are small unless they are saturated.

  Therefore, only by providing the thin non-magnetic layer 200A described above, leakage magnetic flux flowing in the circumferential direction through the two electromagnetic steel plates 2000 adjacent to each other, and leakage magnetic flux flowing in the circumferential direction through the two electromagnetic steel plates 2001 adjacent to each other. It can be greatly reduced. As a result, eddy current loss can be reduced. However, this embodiment has a drawback that the magnetic flux density increases because there is a time for the magnetic flux to flow only through some of the electromagnetic steel sheets 2000 and 2001 constituting the stator segment 3A and the rotor segment 7.

(Example 10)
A description will be given with reference to the SRM of the tenth embodiment. In this embodiment, various structures for suitably forming the stator segment and the rotor segment 7 of the axially extending segment SRM with laminated soft magnetic steel sheets will be described.
29A is an axial cross-sectional view of one stator segment 3A, and FIG. 29B is a cross-sectional view taken along line AA of the stator segment 3A in FIG. 29A. Since the stator segment 3A is formed in a C shape, it is also called a claw pole core. The stator segment 3 </ b> A includes a first stacked portion 301 and a second stacked portion 302. Reference numeral 300 denotes a stator magnetic pole surface (rotor facing surface) which is a tip surface of two stator magnetic poles of the stator segment 3A. 4A is a ring coil that is an AC coil, and 9A is a ring coil that is a DC coil. The illustration of the rotor segment is omitted.

The 1st lamination | stacking part 301 is comprised by laminating | stacking an electromagnetic steel plate in the circumferential direction (tangential direction). The first laminated portion 301 includes a C-shaped C-shaped portion 301A surrounding the ring coils 4A and 9A penetrating the slot S, an inner claw portion 301B and an outer claw portion protruding from both ends of the C-shaped portion 301A in the axial direction. 301C. The pair of inner claw portions 301B squeeze the opening of the slot S. The pair of outer claw portions 301C have a right triangle shape whose radial width increases as the distance from the C-shaped portion 301A increases in the axial direction.
Each electromagnetic steel plate constituting the second laminated portion 302 is laminated in the radial direction and the axial direction. The second stacked portion 302 is formed in a C-shape, and extends in the axial direction and the radial direction in contact with the outer surface of the C-shaped portion 301A of the first stacked portion 301. The tip end portion 302A of the second stacked portion 302 has a pointed shape that protrudes radially inward as it approaches the C-shaped portion 301A. The two tip portions A are press-fitted between the C-shaped portion 301A and the outer claw portion 301C of the first laminated portion 301.

The contact surface between the first laminated portion 301 and the second laminated portion 302 is coated with an adhesive in which a large amount of pure iron powder having soft magnetism is mixed. The 1st laminated part 301 and the 2nd laminated part 302 are adhere | attached.
The C-shaped stator segment 3A of this embodiment has a pair of tip portions (stator magnetic poles) composed of a first laminated portion 301 made of a circumferential laminated steel plate. Therefore, as described with reference to FIG. 28, the magnetic flux tends to leak in the circumferential direction between the plurality of steel plates stacked in the circumferential direction. However, the stator segment 3A moves in the circumferential direction in the second stacked portion 302 because the magnetic flux that has entered the first stacked portion 301 flows into the tip of the second stacked portion 302 that is stacked in the axial direction. be able to. Therefore, the magnetic resistance of the stator segment 3A is reduced. That is, in this embodiment, since the magnetic flux can flow in the circumferential direction by entering the second laminated portion 302 from the first laminated portion 301 of the stator segment 3A, the iron loss increases due to the magnetic flux concentration described above. Can be prevented.

Furthermore, in this embodiment, since the axial width and radial width of the C-shaped portion 301A of the first laminated portion 301 are narrow, it is possible to deform the first laminated portion 301 and cover the ring coils 4A and 9A. . Then, the C-shaped stator segment 3 </ b> A can be completed by press-fitting the distal end portion of the second stacked portion 302 into the first stacked portion 301.
A single-phase axially extending segment SRM can be configured by causing two stator magnetic poles (tip portions) of the stator segment 3A shown in FIG. 29 to face one rotor segment 7. By arranging three single-phase SRMs adjacent to each other in the axial direction, a three-phase axially extending segment SRM having a ring coil can be realized. Of course, the circumferential positional relationship between the stator magnetic poles of the single-phase SRM of each phase and the rotor segment is different by being shifted by 2π / 3. Hereinafter, this three-phase SRM is referred to as a C-shaped stator segment tandem arrangement type three-phase SRM.

  A manufacturing example of the second stacked unit 302 will be described with reference to FIG. A central portion in the longitudinal direction of a laminated member 3020 in which a predetermined number of elongated rectangular electromagnetic steel plates are laminated is sandwiched between molds 601 and 602. Both sides of the upper end of the mold 600 are chamfered. Both ends of the laminated member 3020 are bent toward the mold 600 side. Thereby, the second stacked portion 302 can be formed. Preferably, the laminated member 3020 has a number of electromagnetic steel sheets that is 10 to 20% of the number of electromagnetic steel sheets of the second laminated portion 302. Thereby, it can be bent easily. That is, a small number (5 to 10 sheets) of the laminated members 3020 are bent using the molds 600 having different sizes. Thereafter, a group of a total of 5 to 10 laminated members 3020 that are bent is overlapped to complete the second laminated portion 302. When the laminated members 3020 are bent, the outer laminated member 3020 should be expanded in the axial direction within the elastic deformation range.

FIG. 31A is an axial sectional view of one rotor segment 7, and FIG. 31B is a plan view of the rotor segment 7 of FIG. 31A as viewed from the electromagnetic gap G side. The rotor segment 7 includes a first stacked unit 701 and a second stacked unit 702. Reference numeral 700 denotes a stator facing surface (magnetic pole surface) of the rotor segment 7. Reference numeral 6 denotes a cylindrical nonmagnetic boss portion fitted and fixed to the rotating shaft.
The first laminated portion 701 is configured by laminating a number of electromagnetic steel plates in the circumferential direction (tangential direction). The second laminated portion 702 is configured by laminating a number of electromagnetic steel plates in the axial direction. The second laminated portion 702 is press-fitted into two square holes 600 that are penetrated in the circumferential direction (tangential direction) in the vicinity of the stator facing surface 700 of the second laminated portion 702. The second stacked portion 702 faces the two stator magnetic pole surfaces 300 of the stator segment 3A with the electromagnetic gap G and the thin surface region of the first stacked portion 701 separated from each other. It should be noted that the stator segment 3A and the rotor segment 7 have the same radial cross-sectional shape as the stator segment 3B and the rotor segment 7 shown in FIG. An adhesive mixed with a large amount of soft magnetic pure iron powder is applied to the contact surface between the first laminated portion 701 and the second laminated portion 702, and the adhesive layer 600 containing the iron powder is the first one. The first stacked unit 701 and the second stacked unit 702 are bonded.

The magnetic flux that has entered the first stacked portion 701 from the stator facing surface (magnetic pole surface) 700 of the rotor segment 7 facing the rotor facing surface 300 of the stator segment 3A quickly flows into the second stacked portion 702, and the second stacked portion 702. The inside can be dispersed in the circumferential direction. Therefore, the eddy current loss problem due to the circumferential leakage magnetic flux described in FIG. 28 hardly occurs. The magnetic flux flowing into the second laminated portion 702 moves in the axial direction through the first laminated portion 701 made of laminated electromagnetic steel plates in the circumferential direction.
Ultimately, according to this embodiment, a stator segment and a rotor segment having a laminated structure of electromagnetic steel sheets that can have an inner claw portion 301B that has low iron loss, is easy to manufacture, and can reduce magnetic resistance. be able to.

(Modification 1)
Another manufacturing method of the second laminated portion 302 of the stator segment 3A shown in FIG. 29 will be described with reference to FIG.
In this aspect, the stator segment 3A has a second laminated portion 302 formed by spirally winding a strip-shaped electromagnetic steel sheet having protrusions 3031 and 3032 protruding on both sides in the axial direction. However, in this aspect, each stator segment 3 </ b> A constituting the stator core is connected by a belt-shaped portion 3033. First, a strip-shaped electromagnetic steel sheet is punched to form a tape-shaped steel sheet 3030 having protruding portions 3031 and 3032 and a strip-shaped portion 3033 (FIG. 32A). Next, the tape-shaped steel plate 3030 is spirally wound while the protrusions 3031 and 3032 are bent inward in the radial direction (FIG. 32B), whereby the second stacked portion 302 can be formed. It is preferable that the protrusions 3031 and 3032 bent in the bent direction are bent on both sides in the axial direction within an elastic deformation range when the protrusions 3031 and 3032 are overlapped on the already wound protrusions 3031 and 3032. Protrudes from the belt-like portion 3033 every predetermined distance in the circumferential direction, and the predetermined distance is gradually increased, whereby each stator segment 3A can be manufactured at once by a simple process.

(Modification 2)
The manufacturing method described with reference to FIG. 32 or the C-shaped stator segment manufactured by the manufacturing method described with reference to FIG. 30 may be employed as the rotor segment.
(Modification 3)
In FIG. 32, a claw pole core or a Landel pole core can be created by shifting the protruding portion 3031 protruding leftward from the protruding portion 3032 protruding rightward by the electrical angle π.

(Modification 4)
A modification will be described with reference to FIG. In this modification, a stator segment is formed by combining the second laminated portion made of the axially laminated electromagnetic steel plate shown in FIG. 29 and the first laminated portion made of the circumferential (tangential) laminated electromagnetic steel plate. The technical idea is applied to the stator segment of the axially extending segment SRM shown in FIG.
The stator segment 3 has four stator magnetic poles 31 to 34 and a stator yoke 30 for magnetically short-circuiting them as in FIG. However, in FIG. 33A, only the two stator magnetic poles 32 and 33 and the stator yoke 30 are shown enlarged. FIG. 33B is a side view of the stator segment 3 of FIG. 33A as viewed in the axial direction.

In this embodiment, a square hole 38 is provided at the tip of the stator magnetic poles 31 to 34, and the second laminated portion 39 is press-fitted into the square hole 38. The second laminated portion 39 is formed by laminating rectangular or arcuate electromagnetic steel plates in the axial direction. The second laminated portion 39 is adhered to the stator segment 3 as the first laminated portion with an adhesive containing iron powder.
Magnetic flux that has entered the stator magnetic poles 32 and 33 from a rotor segment (not shown) enters the second laminated portion 39 and is dispersed in the second laminated portion 39 in the circumferential direction. Flowing. Thereby, it is possible to prevent an increase in eddy current loss of the stator segment and an increase in magnetic flux density.

(Example 11)
An SRM according to the eleventh embodiment will be described with reference to FIGS. This embodiment relates to a manufacturing method for suitably manufacturing a C-shaped core surrounding a ring coil employed in the above-described axially extending segment SRM or the like using a spirally wound soft magnetic steel plate. FIG. 34 is a front view of the C-shaped core 400 viewed in the circumferential direction (tangential direction), and FIG. 35 is a side view of the C-shaped core 400 viewed in the axial direction. Hereinafter, the manufacturing method will be described.

  First, a core bar 402 having substantially the same shape as the slot S of the C-shaped core 400 is prepared, and a strip-shaped electromagnetic steel sheet 401 is wound around the core bar 402 for a necessary turn. A one-turn electromagnetic steel sheet includes straight portions 403 and 404 for two stator magnetic poles, a semicircular portion 405 for a stator yoke that magnetically shorts these two stator magnetic poles, and a semicircular portion 406 that cuts and removes most of them. It is divided into and. The center m1 of the semicircular portion 406 is shifted toward the center of the semicircular portion 405. As a result, the semicircle portion 406 is not exactly a semicircle, but is bent sharply from the straight portions 403 and 404. Preferably, it is preferable that the belt-shaped electromagnetic steel sheet 401 is spirally wound after being bent or bent in advance. Thereby, the ring body used as the origin of the C-shaped core 400 shown in FIG. 34 is formed. Next, a resin is applied to the surface of the ring body to integrate the electromagnetic steel sheets.

Next, the portion below the one-dot chain line L of the ring body is cut and removed by liquid cutting with the cutting disk 407 that rotates at high speed about the rotation axis m3. A cylindrical cutting blade 408 is fixed to the outer periphery of the cutting disk 407.
Next, square holes 409 and 410 are penetrated in the straight portions 403 and 404 in the axial direction, and block-shaped electrical steel sheet laminates 411 and 412 are press-fitted into the square holes 409 and 410. As shown in FIG. 35, the electromagnetic steel sheet laminates 411 and 412 are formed by laminating rectangular electromagnetic steel sheets in the circumferential direction (tangential direction). The electromagnetic steel sheet laminates 411 and 412 prevent the electromagnetic steel sheet 401 after being cut from coming apart.
According to this embodiment, since the tips of the straight portions 403 and 404 forming the pair of stator magnetic poles of the C-shaped core 400 can have the claw portions 413 and 413 for narrowing the slot opening, the magnetic resistance to the rotor core can be reduced. Can be reduced. The square holes 409 and 410 may be formed by press forming before the belt-shaped electromagnetic steel sheet 401 is spirally wound.
34. By arranging three C-shaped cores 400 shown in FIG. 34 in the axial direction, the stator segment for the three-phase axially extending segment SRM shown in FIG. 2 can be configured.

(Additional information)
The “inductance increase period Ti”, “inductance decrease period Td”, “peak period Tp”, and “bottom period Tb” in this specification will be described in more detail.
Electromagnetic gap (radial direction in radial gap motor) between stator magnetic pole of stator core wound with phase coil (including ring coil) forming stator coil and salient pole part (also called rotor magnetic pole) of rotor core including rotor segment ) Has a large magnetic resistance. The inductance of the phase coil is inversely proportional to the reluctance of the interlinking magnetic circuit. For this reason, in the above description, it is considered that the inductance of the phase coil increases as the overlapping area So increases, and the inductance of the phase coil decreases as the overlapping area So decreases, as seen from the radial direction. Further, the period in which the overlapping area So maintains the maximum value regardless of the rotor rotation is regarded as the peak period Tp, and the period in which the overlapping area So is 0 regardless of the rotor rotation is regarded as the bottom period Tb.

However, when a large current is applied to the phase coil, the inductance of the phase coil decreases due to the magnetic saturation of the stator core or the rotor core. This means that when this magnetic saturation occurs at the end of the inductance increase period, a period in which the inductance hardly increases even though the inductance increase period occurs. This is the peak period during which the current can be reduced without generating torque by increasing the energization current to the phase coil without increasing the difference between the circumferential width of the stator magnetic pole and the circumferential width of the rotor magnetic pole. Can be set. The formation of the peak period using this magnetic saturation is particularly important in Example 3.
In the present invention, a period in which the inductance is 85% or less, more preferably 90% or less than the peak value, and the inductance increases with time is regarded as the inductance increase period Ti.

Claims (30)

A stator having a soft magnetic stator core around which a stator coil composed of a plurality of phase coils is wound, a rotor disposed in a relatively rotatable manner with a small gap on the peripheral surface of the stator, and different timings for the respective phase coils And a motor driving circuit for passing a substantially trapezoidal wave current, the stator facing surface of the rotor has soft magnetic low magnetic resistance portions at a predetermined pitch in the circumferential direction, and the stator core has soft magnetism. In the switched reluctance motor having a plurality of stator magnetic poles protruding toward the rotor at a predetermined circumferential pitch,
The stator core includes a plurality of soft magnetic stator segments arranged at a predetermined pitch in the circumferential direction and extending substantially in the axial direction,
Each of the stator segments has three or more stator magnetic poles arranged at a predetermined pitch in the axial direction and projecting toward the substantially radial rotor,
The rotor core has a plurality of soft magnetic rotor segments arranged at a predetermined pitch in the circumferential direction and extending substantially in the axial direction,
Each rotor segment is disposed at an axial position where each stator segment can face at least two stator magnetic poles adjacent to each other in the axial direction;
The phase coil of each phase is constituted by a ring coil that passes through a slot provided between the stator magnetic poles of each stator segment and is wound in a substantially circular shape and surrounds the rotor core,
The circumferential relative position between the two stator magnetic poles facing the first rotor segment and the first rotor segment is such that the two stator magnetic poles facing the second rotor segment and the second rotor magnetic pole A predetermined electrical angle in the circumferential direction relative to the circumferential relative position between the rotor segments,
The motor drive circuit energizes the second phase coil that excites the second rotor segment with the phase of the first phase current that energizes the first phase coil that excites the first rotor segment. A switched reluctance motor, wherein the phase angle corresponding to the electrical angle is shifted with respect to the phase of the second phase current. The ring coil has a DC coil for energizing direct current and an AC coil for energizing alternating current housed in each slot between the stator magnetic poles,
2. The switched reluctance motor according to claim 1, wherein the motor driving circuit applies a direct current to each of the DC coils, and supplies a substantially trapezoidal alternating current to the AC coils.   3. The switched reluctance motor according to claim 2, wherein the ring coil forming the DC coil has a smaller conductor cross-sectional area and a larger number of turns than the ring coil forming the AC coil.   When the motor driving circuit is electrically operated, the direction of the magnetic flux formed in the AC current in the inductance reduction period of the AC coil is opposite to the magnetic flux formed by the DC current, and the AC in the inductance increase period of the AC coil. The switched reluctance motor according to claim 2, wherein the AC current is supplied to the AC coil in a direction in which a direction of a magnetic flux forming a current is the same as a direction of a magnetic flux formed by the DC current.   5. The motor drive circuit energizes the DC coil with a DC current that forms a magnetic flux that is substantially equal to and opposite in direction to the alternating current forming magnetic flux during an inductance reduction period of the AC coil during electric operation. Switched reluctance motor.   5. The switched reluctance motor according to claim 4, wherein the motor drive circuit includes a single-phase full frame bridge circuit that supplies power separately to the three AC coils forming the three-phase coils. The motor drive circuit has a three-phase bridge circuit that feeds a three-phase alternating current to the three AC coils that are star-connected to form the three-phase coil.
The three upper arm elements of the three-phase bridge circuit are turned on in order of electrical angle of approximately 2π / 3.
The three lower arm elements of the three-phase bridge circuit are turned on in order of electrical angle of approximately 4π / 3,
5. The switched reluctance motor according to claim 4, wherein a direct current Idc flowing through the DC coil is approximately half of a current of three upper arm elements of the three-phase bridge circuit.   The switched reluctance motor according to claim 2, wherein the motor drive circuit includes a capacitor connected in parallel with the DC coils connected in series.   The switched reluctance motor according to claim 2, wherein the motor driving circuit includes a constant current circuit that supplies a substantially constant current to the DC coils connected in series with each other.   The motor driving circuit includes an oscillation circuit that supplies a high-frequency current to the DC coils connected in series, and a rotor rotation angle that detects a rotation angle of the rotor based on a voltage drop of the plurality of DC coils due to the high-frequency current. The switched reluctance motor according to claim 2, further comprising a detection circuit. The stator segment and the rotor segment are formed by laminating a number of soft magnetic steel plates extending in a substantially axial direction in a tangential direction of the rotor,
2. The switched reluctance motor according to claim 1, wherein radial end portions of the stator segment and the rotor segment are arranged with a step between each other so as to be approximately circular as a whole. The rotor segment includes an axial N-th (N is an integer of 2 or more) and N + 1-th stator poles facing the stator segment, an axial M-th rotor segment facing the stator magnetic pole, and an N + 1-th axial direction of the stator segment. N + 2 and the M + 1th rotor segment in the axial direction facing the second stator pole,
The switched reluctance motor according to claim 11, wherein the rotor core has a high magnetic resistance region located between the M-th rotor segment and the M + 1-th rotor segment and having a large magnetic resistance.   At least one of the stator segment and the rotor segment includes a first laminated portion formed by laminating a number of soft magnetic steel plates extending in a substantially axial direction in a substantially tangential direction of the rotor, and extending in a substantially tangential direction. The switched reluctance motor according to claim 11, wherein the switched reluctance motor is configured in combination with a second laminated portion formed by laminating a plurality of soft magnetic steel plates to be laminated in the axial direction of the rotor.   14. The switched reluctance motor according to claim 13, wherein the first laminated portion has a hole portion that is located in a vicinity of a tip portion of the stator magnetic pole and is opened in a substantially circumferential direction to accommodate the second laminated portion.   The switched reluctance motor according to claim 13, further comprising an adhesive layer that contains soft magnetic iron powder and adheres the second laminated portion to the first laminated portion.   The said 2nd lamination | stacking part consists of a C-shaped core comprised by laminating | stacking a substantially C-shaped soft magnetic steel plate in an axial direction and radial direction, and a pair of front-end | tip part protrudes toward the said rotor. Switched reluctance motor.   The second laminated portion is formed by spirally winding a long soft magnetic steel plate having a pair of projecting portions projecting on both sides in the width direction and bending the pair of projecting portions toward the rotor. Switched reluctance motor.   The said stator core has a C-shaped cross section which has a C-shaped cross section which wraps parts other than the said rotor side of the said ring coil, and is comprised by laminating | stacking a soft magnetic steel plate in the direction away from the said ring coil. Switched reluctance motor.   19. The C-shaped core is formed by spirally winding a long soft magnetic steel plate having a pair of protrusions protruding on both sides in the width direction and bending the pair of protrusions toward the rotor. Switched reluctance motor. The ring coil is formed by spirally winding a long insulating coated conductive metal plate having a constant thickness in the direction of arrangement of the plurality of stator magnetic poles of one stator segment,
The switched reluctance motor according to claim 1, wherein each turn of the ring coil is stacked in a direction in which the plurality of stator magnetic poles of the stator segment are arranged. The rotor core includes a non-magnetic boss portion fitted to a rotation shaft, and the rotor segment that is fixed to the outer peripheral surface of the boss portion and protrudes on both sides in the axial direction of the boss portion.
The rotor segment has a pair of projecting end portions projecting from both end surfaces of the boss portion to both sides in the axial direction,
The switched reluctance motor according to claim 1, wherein the ring coil and the stator magnetic pole are disposed on both radial sides of the protruding end portion of the rotor segment. A stator having a soft magnetic stator core around which a stator coil composed of a plurality of phase coils is wound, a rotor disposed in a relatively rotatable manner with a small gap on the peripheral surface of the stator, and different timings for the respective phase coils And a motor driving circuit for passing a substantially trapezoidal wave current, the stator facing surface of the rotor has soft magnetic low magnetic resistance portions at a predetermined pitch in the circumferential direction, and the stator core has soft magnetism. In the switched reluctance motor having a plurality of stator magnetic poles protruding toward the rotor at a predetermined circumferential pitch,
The phase coil is disposed between the inductance increase period and the next inductance decrease period, and is disposed between the inductance decrease period and the next inductance increase period, and the bottom is small. Have a period,
The inductance increase period of the other phase coil is set substantially continuously to the inductance increase period of the phase coil of one phase,
The motor drive circuit substantially completes the rising of the energization current to the phase coil during the bottom period, and almost completes the fall of the energization current to the phase coil during the peak period. motor. The stator core includes a plurality of soft magnetic stator segments arranged at a predetermined pitch in the circumferential direction and extending substantially in the axial direction,
Each of the stator segments has three or more stator magnetic poles arranged at a predetermined pitch in the axial direction and projecting toward the substantially radial rotor,
The rotor core has a plurality of soft magnetic rotor segments arranged at a predetermined pitch in the circumferential direction and extending substantially in the axial direction,
Each rotor segment is disposed at an axial position where each stator segment can face at least two stator magnetic poles adjacent to each other in the axial direction;
The circumferential relative position between the two stator magnetic poles facing the first rotor segment and the first rotor segment is such that the two stator magnetic poles facing the second rotor segment and the second rotor magnetic pole A predetermined electrical angle in the circumferential direction relative to the circumferential relative position between the rotor segments,
When the circumferential pitch of the rotor segment and the circumferential pitch of the stator segment are each an electrical angle of 2π, the stator magnetic pole has a circumferential width of approximately an electrical angle π, and the rotor segment has an electrical angle of approximately 2π / 3. The switched reluctance motor according to claim 22, having a circumferential width.   The switched reluctance motor according to claim 23, wherein the motor drive circuit advances the energization start point in the bottom period when generating a large torque, and delays the energization start point in the bottom period when generating a small torque. A stator having a soft magnetic stator core around which a stator coil composed of a plurality of phase coils is wound, a rotor disposed in a relatively rotatable manner with a small gap on the peripheral surface of the stator, and different timings for the respective phase coils And a motor driving circuit for passing a substantially trapezoidal wave current, the stator facing surface of the rotor has soft magnetic low magnetic resistance portions at a predetermined pitch in the circumferential direction, and the stator core has soft magnetism. In the switched reluctance motor having a plurality of stator magnetic poles protruding toward the rotor at a predetermined circumferential pitch,
The switched reluctance motor, wherein the motor drive circuit includes an acceleration circuit that accelerates a rising period or a falling period of a phase current energized to the phase coil.   The acceleration circuit includes a high side switch that connects a high potential end of a DC power source and a high potential end of a phase coil, a low side switch that connects a low potential end of the DC power source and a low potential end of the phase coil, A low-side diode connecting the low-potential end of the DC power supply and the high-potential end of the phase coil; a reactor and a high-side diode connected in series; and the high-potential end of the DC power supply and the low potential of the phase coil The switched reluctance motor according to claim 25, further comprising a high-side bypass circuit connecting the ends. One end of the reactor is connected to the high potential end of the DC power supply,
27. The switched reluctance motor according to claim 26, wherein the other end of the reactor is connected to a low potential end of different phase coils through the different high side diodes.   The acceleration circuit includes a high side switch that connects a high potential end of a DC power source and a high potential end of a phase coil, a low side switch that connects a low potential end of the DC power source and a low potential end of the phase coil, A reactor having one end connected to the high potential end of the DC power source, an acceleration switch connecting the other end of the reactor and the low potential end of the DC power source, and a connection point between the reactor and the acceleration switch as the phase The switched reluctance motor according to claim 25, further comprising a high side diode connected to a high potential end of the coil.   29. The switched reluctance motor according to claim 28, wherein a connection point between the reactor and the acceleration switch is connected to the other end of different phase coils through the different high side diodes. The acceleration circuit includes a switching element that connects a low potential end of the phase coil and a low power supply bus, and a diode for preventing backflow,
A connection point between the low-potential end of the phase coil and the high-potential end of the switching element and the high-potential end of the assist coil are connected through the backflow prevention diode so that the phase coil is turned off when the switching element is off. 26. The switched reluctance motor according to claim 25, wherein the magnetic energy is passed through the assist coil.

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