WO2023216635A1

WO2023216635A1 - Axial flux switched reluctance motor having wide and narrow stator poles, and control method therefor

Info

Publication number: WO2023216635A1
Application number: PCT/CN2022/144411
Authority: WO
Inventors: 陈昊; 王星; 常喜强; 卢其威; 董利江
Original assignee: 中国矿业大学
Priority date: 2022-05-12
Filing date: 2022-12-31
Publication date: 2023-11-16
Also published as: CN114726180A

Abstract

The present invention relates to the technical field of switched reluctance motors, and disclosed are an axial flux switched reluctance motor having wide and narrow stator poles, and a control method therefor. The axial flux switched reluctance motor having wide and narrow stator poles has a double stator disc and single rotor disc structure, and stator teeth at two sides are opposingly installed at two sides of the rotor disc; said motor comprises a left stator, a right stator, and a rotor; the left stator and the right stator teeth are opposingly placed at two sides of the rotor, and an air gap is left in the middle; the left stator and the right stator are salient pole structures with wide poles and narrow poles in a staggered arrangement; concentrated windings are wound on wide poles of the left stator and the right stator; and winding coils in stator slots of the left stator and the right stator at a same position have opposite polarities. Due to only one phase winding coil being placed in each stator slot and the rotor utilizing a segmented rotor structure, an excitation magnetic flux forms a short magnetic flux path between a wide stator pole and an adjacent narrow stator pole, same has a short axial length, the magnetic flux path is short, same operates reliably, has a high power density, and has a wide range of rotating speeds.

Description

A wide and narrow stator pole axial flux switched reluctance motor and its control method

Technical field

The invention belongs to the technical field of switched reluctance motors, and specifically relates to a wide and narrow stator pole axial flux switched reluctance motor and a control method thereof.

Background technique

The switched reluctance motor has a simple and solid structure, flexible control, and no maintenance. However, it also has problems such as low torque density, large torque ripple, and high noise. In recent years, due to the increasing shortage and rising prices of rare earth materials required for permanent magnet motors, the attractiveness of switched reluctance motor drives has increased significantly, especially for the electric vehicle industry, which pays attention to cost and reliability. Axial flux motors have the characteristics of large output torque, short axial length, and compact structure. They are superior to the same traditional radial magnetic field motors in terms of volume, weight, and noise. They are suitable for applications requiring emergency start, emergency stop, and accurate operation. Positioning and other types of mechanical devices.

The switched reluctance motor is combined with the axial magnetic field structure to form an axial flux switched reluctance motor, which has the comprehensive advantages of the switched reluctance motor and the axial magnetic field motor. The radial length of the axial flux switched reluctance motor from the outer diameter of the stator to the inner diameter of the stator is the effective area for the motor to generate torque. With proper magnetic circuit design, the stator and rotor cores can be fully utilized. Axial flux motors typically provide higher torque density and power density than equivalent radial flux motors. At the same time, axial flux switched reluctance motors with small axial length are suitable for applications that have special requirements on motor volume, such as electric vehicle wheel hub motors.

Contents of the invention

In view of the shortcomings of the existing technology, a wide and narrow stator pole axial flux switched reluctance motor and its control method are provided, which have small axial length, short flux path, reliable operation, high power density and wide speed range.

In order to achieve the above objects, embodiments of the present invention adopt the following technical solutions:

A wide and narrow stator pole axial flux switched reluctance motor has a double stator disk and a single rotor disk structure. The stator tooth poles on both sides are installed on both sides of the rotor disk oppositely, including a left stator, a right stator and a rotor. The tooth poles of the left stator and the right stator are placed oppositely on both sides of the rotor, with an air gap left in the middle. Both the left stator and the right stator have a salient pole structure with interlaced wide poles and narrow poles, and concentrated windings are wound around the stator. On the wide poles of the left stator and the right stator, the winding coils of the left stator and the right stator in the stator slots at the same position have opposite polarities. Due to the characteristics of only one phase winding coil being placed in each stator slot, the rotor adopts a split With the block rotor structure, the excitation flux forms a short flux path between adjacent stator wide poles and stator narrow poles;

The left stator includes a left stator yoke, a left stator wide pole and a left stator narrow pole. The right stator includes a right stator yoke, a right stator wide pole and a right stator narrow pole. The left stator and the right stator have exactly the same structure. The left stator wide pole and the left stator narrow pole are spaced apart, and a stator slot is provided between them; each stator slot is provided with a centralized winding, but it is only wound on the left stator wide pole and the right stator wide pole. The left stator The narrow pole and the narrow pole of the right stator are not wound with windings and only provide a path for the excitation flux; the radially opposite winding coils on one side of the stator are connected in series, and then connected in series or parallel with the winding coils at the same position on the other side; rotor It consists of several segmented rotors. These segmented rotors are fixed in a circular rotor fixed plate. Some segmented rotor cores are embedded in a non-magnetic fixed plate. The rotor fixed plate is made of a ring that is neither magnetic nor electrically conductive. Made of laminated oxy resin materials, it plays the role of isolating the magnetic circuit and reducing eddy current losses;

The main magnetic flux of the motor is generated by the excitation winding installed in the stator slot. At the rotor alignment position, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole, sequentially passes through the left stator yoke, and passes through the adjacent stator narrow pole. And passes through the air gap between the narrow pole of the left stator and the rotor block, enters the rotor block, then passes through the air gap between the rotor block and the wide pole of the left stator, and returns to the wide pole of the stator to form a closed magnetic circuit. The magnetic flux path generated by the winding coil is the same as the magnetic path generated by the left stator; in the misaligned position of the rotor, due to the opposite polarity of the relative position of the stator slot, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole and passes through The left stator yoke passes through the adjacent stator narrow pole, passes through the air gap between the left stator narrow pole and the rotor block, and enters the rotor block; at the same time, the magnetic flux generated by the winding in the right stator slot starts from the right stator wide pole. After passing through the right stator yoke, passing through the adjacent stator narrow pole, and passing through the air gap between the right stator narrow pole and the rotor block, it also enters the rotor block, forming a magnetic circuit. The magnetic flux generated by the stators on both sides is in the misaligned position. cancel each other out, which causes the motor to acquire misaligned flux links.

Further, assuming that the number of stator slots on one side is N _s , the number of block rotors is N _r , and m is the number of motor phases, then N _s =2km,

or

where k is a positive integer. In a single-sided stator, the number of wide poles and the number of narrow poles are equal, both are

N _r segmented rotors are equally spaced along the circumference, and the distribution spacing is 360°/N _r .

Furthermore, in order to ensure the circulation of the excitation path, the pole arc angle of the stator wide pole at different radii is twice that of the stator narrow pole. The rotor block pole arc width is equal to the stator wide tooth pole width and is twice the stator narrow pole width.

Furthermore, in order to ensure that the slot fill rate of the motor is the same at different radii, the stator slots between adjacent stator tooth poles have a parallel slot structure; the pole arc width of the stator narrow pole at the center line of the inner and outer diameters is equal to the stator yoke height, and the rotor The extreme height is twice the height of the stator yoke.

Furthermore, N _r segmented rotors are embedded in a rotor fixed disk made of epoxy resin material that is neither magnetic nor electrically conductive, which plays a role in isolating the magnetic circuit, reducing losses and wind resistance, and improving efficiency.

Furthermore, concentrated coils radially opposite to each other on the same side of the stator are connected in series to form an excitation winding. The stator windings on both sides can be connected in series or in parallel. Different winding connection methods obtain different motor characteristics; according to different working conditions, the stator windings on both sides can be connected in series or in parallel. The same phase coil can switch between series and parallel working modes; the excitation winding is connected to an external main circuit, and the external main circuit is an improved asymmetric half-bridge circuit.

Furthermore, different control methods are selected according to the different speeds of the motor, that is, the current chopping control method of left and right windings in series is used at low speeds, the angle position control method of left and right windings in series is used at medium and low speeds, and the left and right windings are connected in parallel at medium and high speeds. The current chopper control method adopts the angle position control method of parallel connection of left and right windings at high speed; the free switching between winding connection methods and control methods ensures the efficient operation of the motor in a wide speed range.

An excitation control circuit for a wide and narrow stator pole axial flux switched reluctance motor, a three-phase 12-slot 10-pole double-wide and narrow stator pole axial flux switched reluctance motor, with a total of 12 winding outlets, one phase of the stator on each side The winding coil has two connection ends, namely the first connection end and the second connection end;

Each fixed-width sub-pole is wound with an excitation coil. The excitation coil adopts the polarity configuration of NNNSSS for the left stator, and the polarity configuration of the right stator is SSSNNN; or the left stator adopts the polarity configuration of NSNSNS, and the right stator adopts the polarity configuration of NSNSNS. The polarity configuration of SNSNSN is connected in series to form the excitation winding; each set of coils is wound in the same way and has two connecting ends, namely the first connecting end and the second connecting end;

The A phase of the left stator is: the two sets of coils that are radially opposite in space are the same group. The first connection end of the first set of coils is used as the first outlet terminal AL+ of the group of windings, and the second connection end of the first set of coils is Connected to the first connection end of the second set of coils in the same group, the second connection end of the second set of windings in the group serves as the second outlet terminal AL-. For the B phase and C phase of the left stator, the same principle includes the first outlet terminal BL+ and CL+ and the second outlet terminals BL- and CL-; in the same way, the A phase, B phase and C phase of the right stator all have two outlet terminals, respectively the first outlet terminals AR+, BR+ and CR+ and the second outlet terminals. Two outlet terminals AR-, BR- and CR-;

The excitation control circuit is an asymmetric half-bridge circuit that can provide series-parallel mode switching. It selects series mode at low speed and switches to parallel mode at high speed, which expands the efficient speed range of the motor;

A winding mode selection circuit composed of stator winding coils on both sides and a switch, the switch is a relay;

A-phase excitation control circuit of the left stator or right stator: the source of the MOSFET switch SA1 is connected to the first outlet terminal AR+ of the winding AR, and the source of the MOSFET switch SA1 is connected to one end of the relay SA3 at the same time. The second outlet terminal AR- is connected to one end of the relay SA4 and one end of the relay SA5. The other end of the relay SA3 is connected to the other end of the relay SA4. The other end of the relay SA3 is also connected to the first outlet terminal AL+ of the winding AL. The winding AL The second terminal AL- is connected to the other end of the relay SA5, and the second terminal AL- of the winding AL is simultaneously connected to the drain of the MOSFET switch SA2;

The excitation control circuits of phase B and phase C of the left stator or right stator are the same as those of phase A;

In series mode, SA4, SB4, and SC4 are closed, and SA3, SB3, SC3, SA5, SB5, and SC5 are open circuit; in parallel mode, SA4, SB4, and SC4 are open circuit, and SA3, SB3, SC3, SA5, SB5, and SC5 are open circuit. Close, by controlling the opening and closing of the relay, the motor winding can be freely switched between series and parallel modes.

A speed regulation control method for the excitation control circuit in a wide and narrow stator pole axial flux switched reluctance motor, the steps are:

Through the rotary encoder installed on the motor shaft, the rotor position angle of the motor is detected to obtain the actual speed of the motor. The AL phase, AR phase, BL phase, BR phase, CL phase, CR phase current;

Adjust the motor operation by controlling the opening and closing status of the relay. The motor starts to work. SA4, SB4, SC4 are closed, and SA3, SB3, SC3, SA5, SB5, SC5 are open circuit. When the motor works in series mode, when the actual speed value of the motor When n is less than the reference speed n1, at the same time, the MOSFET switch tube selects the current chopper control method in the winding series mode; when the motor continues to accelerate and the actual speed of the motor is greater than the reference speed n1 but less than the reference speed n2, SA4, SB4, SC4 closed, SA3, SB3, SC3, SA5, SB5, SC5 are open circuit, and the MOSFET switch tube selects the angle position control method in the winding series mode; the motor continues to accelerate, and the actual speed of the motor is greater than the reference speed n2 but less than the reference speed n3 When , the motor needs to switch from series mode to parallel mode, SA4, SB4, SC4 are open, SA3, SB3, SC3, SA5, SB5, SC5 are closed, and at the same time, the MOSFET switch tube selects the current chopper control method in the winding parallel mode; when The motor continues to accelerate. When the actual speed of the motor is greater than the reference speed n3, SA4, SB4, and SC4 are open, and SA3, SB3, SC3, SA5, SB5, and SC5 are closed. At the same time, the MOSFET switch tube selects the angle position control method in the winding parallel mode.

Compared with the prior art, the present invention has the following significant advantages:

1. Combine the wide and narrow stator pole switched reluctance motor with the axial magnetic field structure to form the wide and narrow stator pole axial flux switched reluctance motor. While the switched reluctance motor has the advantages of simple structure and flexible control, it also has the advantages of axial magnetic field. The magnetic field motor has the advantages of short axial length and high power density.

2. Through a novel magnetic circuit design, the present invention designs the stator poles into two structures: wide pole and narrow pole. The excitation winding is wound on the wide pole of the stator, while the winding is not wound on the narrow pole and only provides a path for the excitation flux. The opposite polarity configuration of the left and right stator winding coils and the block rotor structure design enable the motor to obtain a shorter magnetic flux path, and at the same time have a larger maximum to minimum inductance ratio, which improves the motor's operating efficiency and power density.

3. The rotor adopts a block structure, which consists of several block rotor cores inserted into a rotor fixed plate made of epoxy resin material. The rotor fixed plate has a smooth surface, which can isolate the magnetic circuit, reduce losses and wind resistance. effect. The epoxy resin material is neither magnetic nor electrically conductive and has a low density, which can reduce the rotor's moment of inertia and improve the motor's dynamic response speed.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of the overall structure of a wide and narrow stator pole axial flux switching reluctance motor according to an embodiment of the present invention;

Figure 2(a) is a schematic diagram of the winding configuration of the left stator NNNSSS and right stator SSSNNN deployed along the outer diameter circumference of the motor provided by the embodiment of the present invention;

Figure 2(b) is a schematic diagram of the winding configuration of the left stator NSNSNS and right stator SNSNSN deployed along the outer diameter circumference of the motor provided by the embodiment of the present invention;

Figure 3 is a rotor plan view of the motor structure provided for the embodiment of the present invention;

Figure 4(a) is a schematic diagram of the main magnetic flux at the alignment position (maximum inductance position) of phase B of the motor provided by the embodiment of the present invention;

Figure 4(b) is a schematic diagram of the main magnetic flux at the misaligned position (minimum inductance position) of phase B of the motor provided by the embodiment of the present invention;

Figure 5(a) is a schematic diagram of the switch of the external circuit used in the motor working in series mode according to the embodiment of the present invention;

Figure 5(b) is a schematic diagram of the switch of the external circuit used in the motor working in parallel mode according to the embodiment of the present invention;

Figure 6 is a control system block diagram under the motor hybrid speed regulation control method provided by the embodiment of the present invention;

Figure 7 is a schematic diagram of control mode switching under the motor hybrid speed regulation control method provided by the embodiment of the present invention;

Reference signs: 1—left stator, 2—right stator, 3—rotor, 1-1—left stator yoke, 1-2—left stator wide pole, 1-3—left stator narrow pole, 2-1— Right stator yoke, 2-2—right stator wide pole, 2-3—right stator narrow pole, 3-1—blocked rotor, 3-2—rotor fixed disk, 4—misaligned position flux path, 5—alignment Position flux path.

Detailed ways

The embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

Embodiments of the present invention provide a wide-narrow stator pole axial flux switched reluctance motor, as shown in Figure 1. The motor includes: a left stator 1, a right stator 2, a rotor 3 and a centralized excitation winding.

The left stator 1 and the right stator 2 have exactly the same structure. The left stator 1 is composed of the stator yoke 1-1, the stator wide pole 1-2 and the stator narrow pole 1-3. The right stator 2 is composed of the stator yoke 2- 1. It consists of stator wide poles 2-2 and stator narrow poles 2-3. The stator wide poles and stator narrow poles appear at intervals, and there are slots between them.

Concentrated windings are provided in each slot, but they are only wound on the stator wide poles 1-2 and 2-2. The stator narrow poles 1-3 and 2-3 are not wound with windings and only provide a path for the excitation flux.

The tooth poles of the left stator 1 and the right stator 2 are placed oppositely on both sides of the rotor 3, with an air gap in the middle.

In this embodiment, the number of single-sided stator slots is N _s , the number of segmented rotors is N _r , and m is the number of motor phases. Then there is N _s =2km,

or

where k is a positive integer. In a single-sided stator, the number of wide poles and the number of narrow poles are equal, both

In the preferred solution of this embodiment, the axial flux switched reluctance motor has a 12k/10k three-phase structure, in which the number of stator poles (slots) is 12k and the number of rotor poles is 10k, where k is a positive integer. .

For example: As shown in Figure 1, a dual-stator axial flux switched reluctance motor structure with 12 slots and 10 poles and wide and narrow stator poles is used, that is, the number of stator poles on one side is 12 and the number of block rotors is 10.

In this embodiment, there are two winding polarity configurations: one is as shown in Figure 2(a), the left stator adopts the polarity configuration of NNNSSS, and the right stator adopts the polarity configuration of SSSNNN; the second one is as shown in Figure 2(a) As shown in 2(b), the left stator adopts the polarity configuration of NSNSNS, and the right stator adopts the polarity configuration of SNSNSN.

In a preferred solution of this embodiment, the axial flux switched reluctance motor adopts the winding polarity configuration of NNNSSS.

Figure 3 is a screenshot of the rotor plane of the wide and narrow stator pole axial flux switched reluctance motor structure. It can be seen that the rotor 3 of the axial flux switched reluctance motor consists of a segmented rotor core 3-1 and a non-magnetic fixed disk. It is composed of 3-2, and all the segmented rotor cores 3-1 are embedded in the non-magnetic fixed disk 3-2. The rotor fixed disk 3-2 is made of laminated epoxy resin material that is neither magnetic nor electrically conductive, and plays the role of isolating the magnetic circuit and reducing eddy current losses.

In the existing technology, the excitation magnetic circuit of the axial flux switched reluctance motor is long, resulting in low excitation efficiency and increased losses.

The stator core of the wide and narrow stator pole axial flux switched reluctance motor in the embodiment of the present invention has a salient pole structure in which wide poles and narrow poles alternate. The rotor core has a block structure, and concentrated windings are wound around the wide poles of the stator. As shown in Figure 2, the polarity of the winding coils in the slots of the stator on both sides is opposite. Since only one phase winding coil is placed in each slot and the rotor adopts a block rotor structure, the excitation flux forms a short flux path between the adjacent stator wide poles and stator narrow poles.

Define the misaligned position: define the alignment position of the stator wide pole center line and the segmented rotor core center line as the misaligned position of the motor;

Define the alignment position: Define the alignment position of the center line of the stator wide pole and the center line of the segmented rotor slot as the alignment position of the motor.

Figure 4(a) shows the alignment position flux path of the wide and narrow stator pole axial flux switched reluctance motor, and Figure 4(b) shows the wide and narrow stator pole axial flux switched reluctance motor. Misalignment position flux path.

It can be found that the main magnetic flux of the motor is generated by the field winding installed in the stator slot. At the rotor alignment position, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole 1-2, passes through the left stator yoke 1-1, passes through the adjacent stator narrow pole 1-3, and passes through the left stator narrow pole The air gap between 1-3 and the rotor block 3 enters the rotor block 3, then passes through the air gap between the rotor block 3 and the left stator wide pole 1-2, and returns to the stator wide pole 1-2 to form a closed magnetic Road 4. The magnetic flux path created by the right stator winding coil is the same as the magnetic path created by the left stator.

In the misaligned position of the rotor, due to the opposite polarity of the stator slots at the opposite positions, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole 1-2, passes through the left stator yoke 1-1, and passes through the adjacent stator narrow pole 1-3, and passes through the air gap between the left stator narrow pole 1-3 and the rotor block 3, and enters the rotor block 3; at the same time, the magnetic flux generated by the winding in the right stator slot starts from the right stator wide pole 2-2, Passing through the right stator yoke 2-1, passing through the adjacent stator narrow pole 2-3, passing through the air gap between the right stator narrow pole 2-3 and the rotor block 3, and also entering the rotor block 3, forming a magnetic circuit 5 . It can be seen that the magnetic flux generated by the stator on both sides cancels each other at the misaligned position, which allows the motor to obtain a smaller misaligned flux linkage.

The invention also provides an excitation control circuit and a speed control method for an axial flux switched reluctance motor. As shown in Figure 2, the winding coils of the same phase on both sides of the stator of the motor are connected in series or in parallel. Different connection methods will obtain different performances.

For the preferred solution of this embodiment, a three-phase 12-slot 10-pole dual-width narrow-pole stator pole axial flux switched reluctance motor has a total of 12 winding outlets, as shown in Figure 2. The one-phase winding coil of the stator on each side has two connection ends, namely a first connection end and a second connection end.

Each fixed-width sub-pole 1-1 is wound with an excitation coil, and the excitation coils are connected in series according to the wiring shown in Figure 2 to form an excitation winding. Each set of coils is wound in the same way and has two connecting ends, namely the first connecting end and the second connecting end.

Taking phase A of the left stator as an example, the two sets of coils that are radially opposite in space are the same group. The first connection end of the first set of coils is used as the first outlet terminal AL+ of the group of windings, and the second connection end of the first set of coils is Connected to the first connection end of the second set of coils of the same group, the second connection end of the second set of windings of the group serves as the second outlet terminal AL-. For the B phase and C phase of the left stator, it also includes the first outlet terminals BL+ and CL+ and the second outlet terminals BL- and CL-.

In the same way, the stator phases A, B and C on the right side all have two outlet terminals, namely the first terminals AR+, BR+ and CR+ and the second terminals AR-, BR- and CR-.

In this embodiment, the excitation control circuit is an asymmetric half-bridge circuit that can provide series-parallel mode switching. Select the series mode at low speed and switch to parallel mode at high speed, which expands the efficient speed range of the motor and is especially suitable for applications such as electric vehicle wheel hub motors.

The asymmetric half-bridge will not be discussed in detail here. This article mainly introduces the winding mode selection circuit composed of stator winding coils and switches on both sides. The switches described in this article are relays.

Specifically: the excitation control circuit shown in Figure 5, taking phase A as an example: the source of the MOSFET switch SA1 is connected to the first outlet terminal AR+ of the winding AR, and the source of the MOSFET switch SA1 is simultaneously connected to the relay SA3. One end is connected, the second outlet terminal AR- of the winding AR is connected to one end of the relay SA4 and one end of the relay SA5, the other end of the relay SA3 is connected to the other end of the relay SA4, and the other end of the relay SA3 is simultaneously connected to the first outlet of the winding AL. terminal AL+ is connected, the second outlet terminal AL- of the winding AL is connected to the other end of the relay SA5, and the second outlet terminal AL- of the winding AL is simultaneously connected to the drain of the MOSFET switch SA2.

The excitation control circuits of phase B and phase C are the same as those of phase A.

In the series mode, as shown in Figure 5(a), SA4, SB4, and SC4 are closed, while SA3, SB3, SC3, SA5, SB5, and SC5 are open. In the parallel mode, as shown in Figure 5(a), SA4, SB4, and SC4 are open, while SA3, SB3, SC3, SA5, SB5, and SC5 are closed.

In this embodiment, the speed control method includes detecting the rotor position angle of the motor through a rotary encoder installed on the motor shaft to obtain the actual rotation speed of the motor. The currents of the AL phase, AR phase, BL phase, BR phase, CL phase and CR phase of the motor are detected through current sensors.

Combining Figure 6 and Figure 7, the process of the hybrid speed control method of the present invention is described as follows. The working status of the MOSFET switch tube in the asymmetric half-bridge will not be described in detail here. The opening and closing status of the relay is mainly introduced: the motor starts When running, SA4, SB4, SC4 are closed, SA3, SB3, SC3, SA5, SB5, SC5 are open circuit, and the motor works in series mode; when the actual speed value n of the motor is less than the reference speed n1, the MOSFET switch tube selects the winding at the same time. Current chopper control method in series mode; When the motor continues to accelerate and the actual speed of the motor is greater than n1 and less than n2, SA4, SB4, SC4 are closed, SA3, SB3, SC3, SA5, SB5, SC5 are open circuit, and at the same time The MOSFET switch tube selects the angular position control method in the winding series mode; the motor continues to accelerate, and when the actual speed of the motor is greater than n2 and less than n3, the motor needs to switch from series mode to parallel mode, SA4, SB4, SC4 are open circuit, SA3, SB3, SC3, SA5, SB5, and SC5 are closed, and the MOSFET switch tube selects the current chopper control method in the winding parallel mode; when the motor continues to accelerate and the actual speed of the motor is greater than n3, SA4, SB4, and SC4 open circuit, and SA3, SB3, SC3, SA5, SB5, and SC5 are closed. At the same time, the MOSFET switch tube selects the angle position control method in the winding parallel mode, and the reference speed n1, n2, and n3 gradually increase.

This speed regulation method realizes the free switching between series and parallel modes of the motor winding by controlling the opening and closing of the relay. The control method is simple and widens the rotation speed range of the wide and narrow stator pole axial flux switching reluctance motor.

Claims

A kind of wide and narrow stator pole axial flux switched reluctance motor, which is characterized in that: it has a double stator disk and a single rotor disk structure, and the stator tooth poles on both sides are installed on both sides of the rotor disk oppositely, including the left stator (1) , the right stator (2) and the rotor (3), the left stator (1) and the right stator (2) tooth poles are placed on both sides of the rotor (3) oppositely, leaving an air gap in the middle, the left stator ( 1) and the right stator (2) both have salient pole structures in which wide poles and narrow poles alternate. Concentrated windings are wound on the wide poles of the left stator (1) and the right stator (2). The left stator (2) 1) The polarity of the winding coils in the stator slots of the right stator (2) at the same position is opposite. Due to the characteristics of only one phase winding coil placed in each stator slot, and the rotor (3) adopts a block rotor structure, the excitation magnetic flux A short flux path is formed between adjacent stator wide poles and stator narrow poles;

The left stator (1) includes the left stator yoke (1-1), the left stator wide pole (1-2) and the left stator narrow pole (1-3), and the right stator (2) includes the right stator yoke (2- 1). The right stator has wide poles (2-2) and the right stator has narrow poles (2-3). The left stator (1) and the right stator (2) have exactly the same structure. The left stator has wide poles (1-2). ) are spaced apart from the left stator narrow poles (1-3), with stator slots between them; each stator slot is equipped with a centralized winding, but it is only wound around the left stator wide poles (1-2) and the right stator wide poles (1-2). On the wide poles of the stator (2-2), the narrow poles of the left stator (1-3) and the narrow poles of the right stator (2-3) are not wound with windings and only provide paths for the excitation flux; the spaces on one side of the stator are radially opposite. The winding coils are connected in series, and then connected in series or parallel with the winding coils at the same position on the other side; the rotor (3) is composed of several segmented rotors (3-1), and these segmented rotors (3-1) are fixed on a circular In the rotor fixed plate (3-2), some block rotor cores (3-1) are embedded in the non-magnetic fixed plate (3-2). The rotor fixed plate (3-2) is made of non-magnetic conductive plates. It is made of laminated non-conductive epoxy resin materials to isolate the magnetic circuit and reduce eddy current losses;

The main magnetic flux of the motor is generated by the excitation winding installed in the stator slot. When the rotor is aligned, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole (1-2) and passes through the left stator yoke (1-1 ), passes through the adjacent stator narrow pole (1-3), passes through the air gap between the left stator narrow pole (1-3) and the rotor block (3), enters the rotor block (3), and then passes through the rotor The air gap between the block (3) and the left stator wide pole (1-2) returns to the stator wide pole (1-2) to form a closed magnetic circuit (4). The magnetic flux path generated by the right stator winding coil is the same as The magnetic circuit generated by the left stator is the same; in the misaligned position of the rotor, due to the opposite polarity of the stator slots in the relative position, the magnetic flux generated by the winding in the left stator slot starts from the left stator wide pole (1-2) and passes through the left stator yoke (1-1), passes through the adjacent stator narrow pole (1-3), passes through the air gap between the left stator narrow pole (1-3) and the rotor block (3), and enters the rotor block (3); At the same time, the magnetic flux generated by the winding in the right stator slot starts from the right stator wide pole (2-2), passes through the right stator yoke (2-1), passes through the adjacent stator narrow pole (2-3), and passes through the right stator narrow pole (2-3). The air gap between the narrow poles of the stator (2-3) and the rotor block (3) also enters the rotor block (3), forming a magnetic circuit (5). The magnetic fluxes generated by the stators on both sides cancel each other out at misaligned positions. This causes the motor to acquire misaligned flux links.
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: assuming the number of stator slots on one side is N s , the number of block rotors is N r , and m is the number of motor phases, then N s =2km,
or
where k is a positive integer. In a single-sided stator, the number of wide poles and the number of narrow poles are equal, both are
N r segmented rotors are equally spaced along the circumference, and the distribution spacing is 360°/N r .
[Correction 02.03.2023 under Rule 91]
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: in order to ensure the circulation of the excitation path, the pole arc angle of the stator wide pole at different radii is twice that of the stator narrow pole, and the rotor The block pole arc width is equal to the stator wide tooth pole width and is twice the stator narrow pole width.
[Correction 02.03.2023 under Rule 91]
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: in order to ensure that the slot fill rate of the motor at different radii is the same, the stator slots between adjacent stator tooth poles are parallel slots Structure: The pole arc width of the narrow pole of the stator at the center line of the inner and outer diameters is equal to the height of the stator yoke, and the pole height of the rotor is twice the height of the stator yoke.
[Correction 02.03.2023 under Rule 91]
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: N r segmented rotors are embedded in a rotor fixed disk made of an epoxy resin material that is neither magnetic nor electrically conductive. , which plays the role of isolating the magnetic circuit, reducing losses and wind resistance, and improving efficiency.
[Correction 02.03.2023 under Rule 91]
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: the centralized coils radially opposite to each other on the same side of the stator are connected in series to form an excitation winding, and the stator windings on both sides can be connected in series or in parallel. The motor characteristics obtained by the winding connection method are different; according to different working conditions, the same phase coils on both sides of the stator can switch between series and parallel working modes; the excitation winding is connected to an external main circuit, and the external main circuit is an improved Asymmetric half-bridge circuit.
[Correction 02.03.2023 under Rule 91]
The wide and narrow stator pole axial flux switched reluctance motor according to claim 1, characterized in that: different control methods are selected according to different rotation speeds of the motor, that is, the current chopper control method of left and right windings in series is used at low speed. The angular position control method of left and right windings in series is used at medium and low speeds, the current chopper control method of left and right windings in parallel is used at medium and high speeds, and the angular position control method of left and right windings in parallel is used at high speeds; the difference between the winding connection method and the control method is Free switching ensures efficient operation of the motor in a wide speed range.
[Correction 02.03.2023 under Rule 91]

An excitation control circuit for a wide and narrow stator pole axial flux switched reluctance motor, which is characterized by: a three-phase 12-slot 10-pole double-wide narrow pole stator pole axial flux switched reluctance motor with a total of 12 winding outlets, one on each side The one-phase winding coil of the stator has two connection ends, namely the first connection end and the second connection end;

Each fixed-width sub-pole (1-1) is wound with an excitation coil. The excitation coil adopts the polarity configuration of NNNSSS for the left stator, and the polarity configuration of the right stator is SSSNNN; or the left stator adopts the polarity configuration of NSNSNS. , the right stator adopts the polarity configuration of SNSNSN and is connected in series to form the excitation winding; each set of coils is wound in the same way and has two connecting ends, namely the first connecting end and the second connecting end;

The A phase of the left stator (1) is: the two sets of coils radially opposite in space are the same group, the first connection end of the first set of coils is the first outlet terminal AL+ of the group of windings, and the first connection end of the first set of coils is The second connection end is connected to the first connection end of the second set of coils in the same group. The second connection end of the second set of windings in the group serves as the second outlet terminal AL-. The same principle applies to phase B and phase C of the left stator (1). Including the first outlet terminals BL+ and CL+ and the second outlet terminals BL- and CL-; in the same way, the A phase, B phase and C phase of the right stator (2) all have two outlet terminals, respectively the first The outlet terminals AR+, BR+ and CR+ and the second outlet terminals AR-, BR- and CR-;

The excitation control circuit is an asymmetric half-bridge circuit that can provide series-parallel mode switching. It selects series mode at low speed and switches to parallel mode at high speed, which expands the efficient speed range of the motor;

A winding mode selection circuit composed of stator winding coils on both sides and a switch, the switch is a relay;

Phase A excitation control circuit of the left stator (1) or right stator (2): the source of the MOSFET switch SA1 is connected to the first outlet terminal AR+ of the winding AR, and the source of the MOSFET switch SA1 is simultaneously connected to the relay SA3 One end is connected, the second outlet terminal AR- of the winding AR is connected to one end of the relay SA4 and one end of the relay SA5, the other end of the relay SA3 is connected to the other end of the relay SA4, and the other end of the relay SA3 is simultaneously connected to the first outlet of the winding AL. terminal AL+ is connected, the second terminal AL- of the winding AL is connected to the other end of the relay SA5, and the second terminal AL- of the winding AL is simultaneously connected to the drain of the MOSFET switch SA2;

The excitation control circuits of phase B and phase C of the left stator (1) or right stator (2) are the same as those of phase A;

In series mode, SA4, SB4, and SC4 are closed, and SA3, SB3, SC3, SA5, SB5, and SC5 are open circuit; in parallel mode, SA4, SB4, and SC4 are open circuit, and SA3, SB3, SC3, SA5, SB5, and SC5 are open circuit. Close, by controlling the opening and closing of the relay, the motor winding can be freely switched between series and parallel modes.
[Correction 02.03.2023 under Rule 91]

A speed regulation control method for an excitation control circuit in a wide and narrow stator pole axial flux switched reluctance motor as claimed in claim 8, characterized in that the steps are:

Through the rotary encoder installed on the motor shaft, the rotor position angle of the motor is detected to obtain the actual speed of the motor. The AL phase, AR phase, BL phase, BR phase, CL phase, CR phase current;

Adjust the motor operation by controlling the opening and closing status of the relay. The motor starts to work. SA4, SB4, SC4 are closed, and SA3, SB3, SC3, SA5, SB5, SC5 are open circuit. When the motor works in series mode, when the actual speed value of the motor When n is less than the reference speed n1, at the same time, the MOSFET switch tube selects the current chopper control method in the winding series mode; when the motor continues to accelerate and the actual speed of the motor is greater than the reference speed n1 but less than the reference speed n2, SA4, SB4, SC4 closed, SA3, SB3, SC3, SA5, SB5, SC5 are open circuit, and the MOSFET switch tube selects the angle position control method in the winding series mode; the motor continues to accelerate, and the actual speed of the motor is greater than the reference speed n2 but less than the reference speed n3 When , the motor needs to switch from series mode to parallel mode, SA4, SB4, SC4 are open, SA3, SB3, SC3, SA5, SB5, SC5 are closed. At the same time, the MOSFET switch tube selects the current chopper control method in the winding parallel mode; when The motor continues to accelerate. When the actual speed of the motor is greater than the reference speed n3, SA4, SB4, and SC4 are open, and SA3, SB3, SC3, SA5, SB5, and SC5 are closed. At the same time, the MOSFET switch tube selects the angle position control method in the winding parallel mode.