V-shaped consequent pole magnetic flux reverse permanent magnet motor

Abstract

The invention discloses a V-shaped consequent-pole magnetic flux reverse permanent magnet motor, which comprises a stator provided with a winding and a permanent magnet and a rotor arranged on the inner side of the stator and coaxially assembled with the stator, the rotor and the stator both adopt a doubly salient structure, the stator is provided with a stator slot, the winding is arranged in the stator slot, the inner ring of the stator is provided with stator teeth, and the stator teeth are arranged in the stator slot. A plurality of stator units are evenly distributed on the stator in the circumferential direction, each stator unit comprises a left stator tooth, a right stator tooth and two V-shaped permanent magnets, the polarities of four single permanent magnets forming the two V-shaped permanent magnets are the same, and ferromagnetic pole shoes beside the permanent magnets automatically serve as the other pole and are of a consequent pole structure. And the two V-shaped permanent magnets in the stator unit are respectively arranged in the left stator tooth and the right stator tooth. The V-shaped permanent magnets are adopted, and the magnetomotive force of the permanent magnets can be effectively increased due to the fact that the V-shaped permanent magnets have the magnetism gathering effect, so that the torque density is increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to a permanent magnet motor. Background Art

[0002] The flux reversal motor has the characteristics of low speed and high torque, and is commonly used in occasions where a relatively high starting torque is required. It is widely used in large-load mechanical equipment such as pumps, compressors, and fans. In 1996, Deodhar_R_P et al. first proposed the model of a new type of doubly salient permanent magnet motor - the flux reversal motor (FRM). The permanent magnets of the flux reversal motor are installed on the stator surface, and it has better heat dissipation ability of the permanent magnets compared with the surface-mounted and interior permanent magnet synchronous motors on the rotor, reducing the risk of irreversible demagnetization of the permanent magnets caused by high temperature. Due to the high industrial demand for permanent magnet materials, the price of permanent magnet materials has gradually increased. In order to reduce the manufacturing cost of motors, the design of the alternating pole flux reversal motor has received considerable attention at the present stage. The alternating pole structure means that the permanent magnets with the same or different polarities of the permanent magnet rotor (stator) are replaced by salient pole iron cores. This structure can not only save permanent magnet materials and improve their utilization rate, but also ensure that the motor has good output torque and dynamic performance. However, the torque density generated by the traditional alternating pole flux reversal motor is small, and there is still room for further improvement. Summary of the Invention

[0003] The present invention provides a V-type alternating pole flux reversal permanent magnet motor to solve the technical problem of low torque density of the traditional alternating pole flux reversal permanent magnet motor.

[0004] To solve the above technical problem, the present invention adopts the following technical solution: A V-type alternating pole flux reversal permanent magnet motor includes a stator provided with windings and permanent magnets, and a rotor arranged inside the stator and coaxially assembled with the stator. Both the rotor and the stator adopt a doubly salient structure. The stator has stator slots, and the windings are arranged in the stator slots. The inner ring of the stator has stator teeth. The stator is circumferentially provided with a plurality of stator units. Each stator unit includes two left and right stator teeth and two V-shaped permanent magnets, and the polarities of the four single permanent magnets constituting the two V-shaped permanent magnets are the same. The iron pole shoes beside the permanent magnets automatically act as the other pole, presenting an alternating pole structure. The two V-shaped permanent magnets in each stator unit are respectively arranged in the left stator tooth and the right stator tooth.

[0005] Preferably, the pole opening angles of the two V-shaped permanent magnets in each stator unit are the same, and the included angles between the midlines of the two V-shaped permanent magnets and the midlines of the corresponding stator teeth are the same.

[0006] Preferably, the widths and thicknesses of the four single permanent magnets constituting the two V-shaped permanent magnets in each stator unit are the same.

[0007] Preferably, the alternating pole arrangement in the stator unit is N-Fe-Fe-N or N-Fe-N-Fe; and / or, the two single permanent magnets forming the V-shaped permanent magnet are connected by a magnetic bridge.

[0008] Preferably, the relative position of the V-shaped permanent magnet is determined by a position ratio, and the position ratio satisfies: P r = α / β, where α represents the angle between the center of the stator tooth and the center of the V-shaped permanent magnet, and β represents the angle from the center line of the stator tooth to the edge of the stator tooth.

[0009] Preferably, the two V-shaped permanent magnets in the stator unit are arranged asymmetrically.

[0010] Preferably, the two single permanent magnets forming the V-shaped permanent magnet have the same amount, and the widths and thicknesses of the two single permanent magnets are different.

[0011] Preferably, the two single permanent magnets forming the V-shaped permanent magnet are in an offset state.

[0012] Preferably, the pole opening angles of the two V-shaped permanent magnets in the stator unit are asymmetric.

[0013] Preferably, the winding adopts a concentrated armature winding or a distributed armature winding; and / or, the winding is a single-layer winding or a double-layer winding; when the alternating pole arrangement in the stator unit is N-Fe-Fe-N, the number of winding pole pairs should satisfy: P = |iZ s / 2 ± Z r |, i = 1, 2, 3…

[0014] When the alternating pole arrangement in the stator unit is N-Fe-N-Fe, the number of winding pole pairs should satisfy: P = |iZ s ± Z r |, i = 1, 2, 3…

[0015] In the formula, P represents the number of winding pole pairs, i represents the harmonic order of the permanent magnetic field, Z s represents the number of stator slots, and Z r represents the number of rotor slots.

[0016] On the basis of adopting the basic structure of the traditional alternating pole flux reversal permanent magnet motor, the present invention adopts a V-shaped permanent magnet. Because the V-shaped permanent magnet has a magnetic concentration effect, the magnetomotive force of the permanent magnet can be effectively increased, thereby increasing the torque density.

[0017] In addition, the present invention also has the following beneficial effects:

[0018] 1. The V-type alternating-pole flux-reversal permanent magnet motor of the present invention adopts the double salient pole structure design of the traditional flux-reversal motor. The permanent magnets are installed on the stator surface, which is convenient for realizing the thermal control of the permanent magnets and reduces the risk of irreversible demagnetization of the permanent magnets caused by high temperature.

[0019] 2. The amount of permanent magnets used in the alternating-pole flux-reversal motor is halved compared with the traditional flux-reversal motor, and all the permanent magnets have the same polarity. The iron pole shoes beside the permanent magnets automatically act as the other pole.

[0020] 3. The V-type alternating-pole permanent magnet arrangement of the V-type alternating-pole flux-reversal permanent magnet motor of the present invention can generate rich permanent magnet magnetomotive force harmonics, and a series of harmonic components are generated in the air gap after being modulated by the rotor teeth. Due to its magnetic concentration effect, the V-type alternating-pole permanent magnet can effectively enhance the main working harmonics among them. Taking the pole-slot combination of 12 stator slots and 17 rotor slots as an example, the V-type alternating-pole permanent magnet can effectively enhance the 1st harmonic with the largest contribution to torque, making it greater than that of the traditional alternating-pole flux-reversal permanent magnet motor. Therefore, the motor of the present invention has higher average torque, higher no-load back electromotive force and lower cogging torque, and can greatly reduce the influences such as motor noise and vibration caused by cogging torque and torque ripple.

[0021] 4. The V-type alternating-pole flux-reversal permanent magnet motor of the present invention has a higher torque density. Compared with the traditional alternating-pole flux-reversal motor of the same specification, the amounts of permanent magnets, stator iron cores, windings, and rotor materials in the motor of the present invention are the same. Therefore, the costs are basically the same under the same motor volume. However, under the same motor volume, in order to reduce the interpolar leakage flux, two permanent magnets are connected by a magnetic bridge. Due to the reduction of interpolar leakage flux, the average torque, output power, and overload capacity of the motor are significantly improved.

[0022] In summary, the V-type alternating-pole flux-reversal motor of the present invention generates more working harmonics after magnetic field modulation. Compared with the traditional alternating-pole flux-reversal motor (CPFRM), the V-type alternating-pole flux-reversal permanent magnet motor of the present invention has higher torque density, power factor, back electromotive force, and efficiency.

[0023] The specific technical solutions and their beneficial effects of the present invention will be described in detail in the following specific embodiments in conjunction with the drawings. Brief Description of the Drawings

[0024] The present invention will be further described below in conjunction with the drawings and specific embodiments:

[0025] Figure 1 is a schematic diagram of the 12-slot 17-pole V-type alternating-pole flux-reversal motor provided in Embodiment 1 of the present invention;

[0026] Figure 2 is a schematic diagram of the traditional alternating-pole flux-reversal motor;

[0027] Figure 3 It is a schematic diagram of the relative positions of the V-shaped permanent magnets in the stator teeth in Embodiment 1;

[0028] Figs. 4(a, b) are the comparison diagrams of the air-gap magnetic flux density between the V-shaped alternating-pole flux-reversal motor of the present invention and the conventional alternating-pole flux-reversal motor in Embodiment 2. Among them, Fig. 4(a) is the waveform diagram of the air-gap magnetic flux density, and Fig. 4(b) is the frequency spectrum of the air-gap magnetic flux density;

[0029] Figs. 5(a, b) are the comparison diagrams of the back electromotive force between the V-shaped alternating-pole flux-reversal motor of the present invention and the conventional alternating-pole flux-reversal motor in Embodiment 2. Among them, Fig. 5(a) is the waveform diagram of the back electromotive force, and Fig. 5(b) is the frequency spectrum of the back electromotive force;

[0030] Figure 6 It is the comparison diagram of the average torque between the V-shaped alternating-pole flux-reversal motor of the present invention and the conventional alternating-pole flux-reversal motor in Embodiment 2;

[0031] Figure 7 It is the comparison diagram of the power factor between the V-shaped alternating-pole flux-reversal motor of the present invention and the conventional alternating-pole flux-reversal motor in Embodiment 2;

[0032] Figure 8 It is the structural schematic diagram of the permanent-magnet asymmetric V-shaped alternating-pole flux-reversal motor of the topology of the present invention in Embodiment 3;

[0033] Figure 9 It is the structural schematic diagram of the pole-offset V-shaped alternating-pole flux-reversal motor of the topology of the present invention in Embodiment 3;

[0034] Figure 10 It is the structural schematic diagram of the adjacent-pole included-angle asymmetric V-shaped alternating-pole flux-reversal motor of the topology of the present invention in Embodiment 3;

[0035] Figure 11 It is the comparison diagram of the average torque between the topology of the asymmetric V-shaped alternating-pole flux-reversal motor and the conventional alternating-pole flux-reversal motor in Embodiment 3;

[0036] In the figures: 1 - winding; 2 - stator slot; 3 - stator tooth; 4 - stator unit; 5 - stator; 6 - V-shaped permanent magnet; 7 - rotor; 8 - single permanent magnet (linear); 9 - left stator tooth; 10 - right stator tooth; 11 - permanent magnet with unequal thickness; 12 - pole-offset angle; 13 - adjacent-pole asymmetric V-shaped angle. Detailed implementation manners

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0038] Those skilled in the art can understand that, without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0039] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms such as "left", "right", "inside", "outside", etc. indicating orientation or positional relationship are only based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / component referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention.

[0040] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0042] As Figure 1As shown in the figure, a V-type alternating pole flux-reversal permanent magnet motor includes a stator 5, a winding 1, a permanent magnet, and a rotor 7. The stator 5 and the rotor 7 are coaxially assembled. The stator 5 is sleeved outside the rotor 7, and there is an air gap between the rotor 7 and the stator 5. Moreover, the stator 5 has stator slots 2, and the winding 1 is placed in the stator slots 2. Both the rotor 7 and the stator 5 adopt a double salient pole structure of a stator permanent magnet type motor. The double salient pole structure installs the permanent magnet on the stator surface, which is convenient for realizing the thermal control of the permanent magnet and reduces the risk of irreversible demagnetization of the permanent magnet caused by high temperature.

[0043] Among them, the stator 5 is composed of a plurality of stator units 4. The stator unit 4 includes a left stator tooth 9, a right stator tooth 10 (here, left and right refer to two opposite directions along the circumferential direction of the stator unit, the same below), and a pair of V-type permanent magnets 6 with a polarity of N. The pair of V-type permanent magnets 6 with a polarity of N are correspondingly arranged at the bottoms of the left and right stator teeth in the stator unit 4. The V-type permanent magnets 6 are magnetized inward along the short sides, and the iron pole shoes beside the permanent magnets automatically act as the other pole, presenting an alternating pole structure. The permanent magnet consumption of the alternating pole flux-reversal motor is reduced by half compared with that of the traditional flux-reversal motor, and all the permanent magnets have the same polarity. The iron pole shoes beside the permanent magnets automatically act as the other pole. Moreover, on the basis of the basic structure of the traditional alternating pole flux-reversal permanent magnet motor, the present invention adopts V-type permanent magnets. Because the V-type permanent magnets have a magnetic concentrating effect, the magnetomotive force of the permanent magnets can be effectively increased, thereby increasing the torque density.

[0044] As an implementation manner, the pole opening angles of the two V-type permanent magnets in the stator unit are the same, and the included angles between the midlines of the two V-type permanent magnets and the midlines of the corresponding stator teeth are the same. The widths and thicknesses of the four strip-shaped single permanent magnets 8 that form the two V-type permanent magnets in the stator unit are the same. This is called a symmetric structure.

[0045] Compared with a traditional alternating pole flux-reversal motor of the same specification, the permanent magnet consumption, stator iron core, winding, and rotor material in the motor of the present invention are the same. Therefore, the cost is basically the same under the same motor volume. However, under the same motor volume, the two single permanent magnets that form the V-type permanent magnet are connected by a magnetic bridge. Due to the reduction of interpolar leakage flux, the average torque, output power, and overload capacity of the motor are significantly improved.

[0046] The described V-type alternating pole permanent magnet arrangement can generate rich permanent magnet magnetomotive force harmonics, which, after being modulated by the rotor teeth, generate a series of harmonic components in the air gap. Due to its magnetic concentration effect, the V-type alternating pole permanent magnet can effectively enhance the main working harmonics among them. Taking the pole-slot combination of 12 stator slots and 17 rotor slots as an example, the V-type alternating pole permanent magnet can effectively enhance the 1st harmonic that contributes the most to the torque, making it greater than that of the traditional alternating pole flux-reversal permanent magnet motor. Therefore, the motor of the present invention has a higher average torque, a higher no-load back electromotive force, and a lower cogging torque, and can significantly reduce the influence of motor noise and vibration caused by cogging torque and torque ripple.

[0047] It can be understood that the described V-type alternating pole flux-reversal permanent magnet motor can be globally optimized by the finite element method to make the V-type alternating pole flux-reversal permanent magnet motor reach the optimal optimized structure, so as to achieve the maximum average torque of the motor structure of the present invention.

[0048] Compared with the traditional alternating pole flux-reversal permanent magnet motor with the optimal structural design and the same usage amount, the V-type alternating pole flux-reversal permanent magnet motor of the present invention has a better magnetic concentration effect, a higher no-load back electromotive force, a lower torque ripple, and a higher power factor, making the no-load and load performances superior to those of the traditional alternating pole flux-reversal permanent magnet motor.

[0049] In addition, the V-type permanent magnet structure also includes an asymmetric type, and the asymmetric type structure includes but is not limited to: the two permanent magnets in the V-type are asymmetric, the pole angle is offset, and the adjacent pole opening angle is asymmetric.

[0050] The following presents three V-type asymmetric alternating pole flux-reversal permanent magnet motors that can produce beneficial effects by applying the technology of the present invention, namely, the two permanent magnets in the V-type are asymmetric, the pole angle is offset, and the adjacent pole opening angle is asymmetric.

[0051] The present invention includes but is not limited to the permanent magnet motors with the above three asymmetric V-type alternating pole structures, and all the asymmetric V-type alternating pole structures fall within the protection scope of the present invention patent.

[0052] The structure of the first V-type asymmetric alternating pole flux-reversal permanent magnet motor is as follows: The motor includes a stator, a winding, a permanent magnet, and a rotor. The winding is placed in the grooves of the stator. The winding adopts a concentrated armature winding or a distributed armature winding, and the winding is a single-layer winding or a double-layer winding. The number of stator grooves is twice the number of stator units. The stator can be composed of several stator units combined along the circumferential direction. Each stator unit has two adjacent stator teeth, and a set of V-type permanent magnets arranged in the order of N-Fe-Fe-N is inserted at the bottom of the adjacent stator teeth. The two permanent magnets in the V-type permanent magnet are magnetized inward along the short side.

[0053] The two permanent magnets in the V-shaped permanent magnet are asymmetric. The two permanent magnets in the V-shaped permanent magnet have the same amount, but their widths and thicknesses are different. The included angles between the center lines of the two V-shaped permanent magnets in a stator unit and the center lines of the stator teeth where they are located are the same, and the magnetic poles are not offset. The pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are the same. To reduce magnetic leakage, the two permanent magnets in a V-shaped structure are connected by a magnetic bridge.

[0054] The structure of the second V-shaped asymmetric alternating pole flux-reversal permanent magnet motor is as follows: The winding is placed in the grooves of the stator. The winding adopts a concentrated armature winding or a distributed armature winding. The winding is a single-layer winding or a double-layer winding. The number of stator grooves is twice the number of stator units. The stator can be composed of several stator units combined in the circumferential direction. The stator unit has two adjacent stator teeth. A set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N (or N-Fe-N-Fe) are inserted at the bottoms of the adjacent stator teeth. The two permanent magnets in the V-shaped permanent magnet are magnetized inward along the short sides.

[0055] The included angles between the center lines of the two V-shaped permanent magnets in a stator unit and the center lines of the stator teeth where they are located are different, and the magnetic poles are in an offset state. The two permanent magnets in the V-shaped permanent magnet have the same amount, and their widths and thicknesses are the same. The pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are the same. To reduce inter-pole magnetic leakage, the two permanent magnets are connected by a magnetic bridge.

[0056] The structure of the third V-shaped asymmetric alternating pole flux-reversal permanent magnet motor is as follows: The motor includes a stator, a winding, a permanent magnet, and a rotor. The winding is placed in the grooves of the stator. The winding adopts a concentrated armature winding or a distributed armature winding. The winding is a single-layer winding or a double-layer winding. The number of stator grooves is twice the number of stator units. The stator can be composed of several stator units combined in the circumferential direction. The stator unit has two adjacent stator teeth. A set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N are inserted at the bottoms of the adjacent stator teeth. The two permanent magnets in the V-shaped permanent magnet are magnetized inward.

[0057] The pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are different. The two permanent magnets in the V-shaped permanent magnet have the same amount, and their widths and thicknesses are the same. The included angles between the center lines of the two V-shaped permanent magnets in a stator unit and the center lines of the stator teeth where they are located are the same, and the magnetic poles are not offset. To reduce inter-pole magnetic leakage, the two permanent magnets are connected by a magnetic bridge.

[0058] In the present invention, the stator is in a stationary state, and the rotor is in a moving state, rotating relative to the stator at a speed of ω. The motor of the present invention generates an armature magnetic field harmonic with the same number of pole pairs, the same rotation direction, and the same speed as the permanent magnetic field by applying a three-phase symmetric alternating current to the stator winding, and then couples with the permanent magnetic field to output a stable torque.

[0059] The winding adopts a concentrated armature winding or a distributed armature winding; and / or, the winding is a single-layer winding or a double-layer winding; when the alternating pole arrangement in the stator unit is N-Fe-Fe-N, the number of pole pairs of the winding should satisfy: P = |iZ s / 2 ± Z r |, i = 1, 2, 3…

[0060] When the alternating pole arrangement in the stator unit is N-Fe-N-Fe, the number of pole pairs of the winding should satisfy: P = |iZ s ± Z r |, i = 1, 2, 3…

[0061] In the formula, P represents the number of pole pairs of the winding, i represents the order of the permanent magnetic field harmonic, Z s represents the number of stator slots, and Z r represents the number of rotor slots.

[0062] Embodiment 1:

[0063] As Figure 1 shown, the present invention provides a V-type alternating pole flux reversal motor with 12 slots and 17 poles, including a stator, a winding, a permanent magnet, and a rotor. The stator and the rotor are coaxially assembled, the stator is sleeved outside the rotor, there is an air gap between the rotor and the stator, and both the rotor and the stator adopt the double salient pole structure of a stator permanent magnet type motor. The stator is composed of multiple stator units. There are two left and right stator teeth and a pair of V-type permanent magnets with a polarity of N in the stator unit. The widths and thicknesses of the permanent magnets are the same. The winding is placed in the grooves of the stator. The stator has stator teeth. The two left and right stator teeth in the stator unit include a pair of V-type permanent magnets with a polarity of N. The pair of V-type permanent magnets with a polarity of N are arranged at the bottoms of the left and right stator teeth in the stator unit in the arrangement order of N-Fe-Fe-N, and the permanent magnets are magnetized inward.

[0064] As Figure 3 shown, the relative position of the V-type permanent magnet is determined by a position ratio, and the position ratio satisfies: P r = α / β. In the formula, α represents the angle between the center of the stator tooth and the center of the V-type permanent magnet, and β represents the angle from the center line of the stator tooth to the edge of the stator tooth.

[0065] As Figure 2As shown, it is a traditional alternating-pole flux-reversal machine with the same design specifications. The arrangement form of the permanent magnets and the stator-rotor structure of this traditional alternating-pole flux-reversal machine are the same as those of the present invention. It should be noted that the permanent magnets of the traditional alternating-pole flux-reversal machine are in a straight-line shape, and the permanent magnets of both machines adopt the N-Fe-Fe-N arrangement.

[0066] Figure 1 and Figure 2 In the structure shown, silicon steel sheets are used for both the stator and rotor materials, and enameled wires are used for the windings and a double-layer concentrated winding is adopted. The structural parameters of the traditional alternating-pole flux-reversal machine and the machine of the present invention are shown in Table 1. The overall dimensions, number of coil turns and rotational speed of the two machines are the same.

[0067] Table 1

[0068]

[0069] Table 2 lists the parameters for the two machines to achieve optimal performance. In order to control variables, the amount of permanent magnets used in the two machines is kept the same. Therefore, the width and thickness of the V-shaped permanent magnets of the present invention are relatively smaller than those of the straight-line-shaped permanent magnets.

[0070] Table 2

[0071] Parameter CP-FRM V-CPFRM Split ratio 0.58 0.56 Stator tooth width coefficient 0.4 0.48 Stator yoke width coefficient 0.7 0.6 Rotor slot opening coefficient 0.7 0.72 V-shaped permanent magnet included angle / 35° Position coefficient (α / β) / 0.42 Current angle 0° 10° Permanent magnet thickness 3mm 2.2mm Permanent magnet width 8.82mm 6.01mm Number of permanent magnet blocks 12 24 Permanent magnet volume <![CDATA[15.88cm 3 > <![CDATA[15.88cm 3 > Rated current 3.29A 3.27A Copper loss 32W 32W

[0072] Example 2:

[0073] Based on Example 1, this example makes a supplementary description of the performance comparison between the V-shaped alternating-pole flux-reversal machine of the present invention and the traditional alternating-pole flux-reversal machine.

[0074] As Figure 1 and Figure 2 shown, the permanent magnets of the flux-reversal machine are installed on the stator surface, which has better heat dissipation ability for the permanent magnets compared with surface-mounted and interior permanent magnet synchronous machines on the rotor, reducing the risk of irreversible demagnetization of the permanent magnets caused by high temperature. And compared with the ordinary surface-mounted flux-reversal machine, the amount of permanent magnets used in the alternating-pole flux-reversal machine is reduced by half. Due to the addition of working sub-harmonics in the alternating-pole flux-reversal machine, its torque density is higher than that of the ordinary surface-mounted flux-reversal machine.

[0075] On this basis, the V-type alternating pole flux-reversal machine proposed by the present invention has better magnetic flux concentration effect and magnetic field modulation effect compared with the traditional alternating pole flux-reversal machine, thus generating a higher fundamental magnetic flux density amplitude and no-load back electromotive force. As shown in Figs. 4(b) and 5(b), the fundamental magnetic flux density amplitude of the V-type alternating pole flux-reversal machine is increased by 2.5% compared with the traditional alternating pole flux-reversal machine, while the no-load back electromotive force is increased by 23%. As shown in Fig. 5(a), due to less leakage magnetic flux between the structures of the machine of the present invention, the fluctuations of the magnetic flux density and back electromotive force waveforms are smaller than those of the traditional alternating pole flux-reversal machine. Therefore, the machine of the present invention has better sinusoidality of the magnetic flux density and back electromotive force waveforms, thereby improving the vibration and noise problems of the machine.

[0076] The number of winding pole pairs of the present invention should satisfy: P = |iZ s / 2 ± Z r |, i = 1, 2, 3…

[0077] In the formula, P represents the number of winding pole pairs, i represents the harmonic order of the permanent magnetic field, Z s represents the number of stator slots, and Z r represents the number of rotor slots. Different from the traditional flux-reversal machine with odd-order magnetic flux density harmonics (i = 1, 3, 5,...), due to the different magnetic reluctances of the ferromagnetic poles and permanent magnets, the alternating pole flux-reversal machine has additional even-order magnetic flux density harmonics (i = 2, 4, 6,...). Therefore, the alternating pole flux-reversal machine through magnetic field modulation can generate more working harmonics, which contribute to the torque.

[0078] More specifically, the magnetic flux densities of the traditional alternating pole flux-reversal machine and the V-type alternating pole flux-reversal machine proposed by the present invention are shown in Fig. 4(a). According to the calculation equation of the number of winding pole pairs, both the 12-slot 17-pole traditional alternating pole flux-reversal machine and the V-type alternating pole flux-reversal machine can generate 6th, 12th, 18th, and 24th (iZs / 2, i = 1, 2, 3, 4) air-gap magnetic flux density harmonics.

[0079] It should be noted that these air-gap magnetic flux density harmonics can generate 1st, 5th, 7th, 11th, 13th, 19th, and 23rd harmonics (|iZs / 2 ± Zr|) that contribute to the torque of the machine after being modulated by the rotor teeth. As shown in Fig. 4(b), since the 18th harmonic is relatively high, the amplitude of the 1st harmonic (the main working harmonic) of the V-type alternating pole flux-reversal machine is greater than that of the traditional alternating pole flux-reversal machine. This means that the V-shaped structure design of the permanent magnet in the machine of the present invention can increase the magnitude of the main working harmonic in the air-gap field. As Figure 6 shown, the V-type alternating pole flux-reversal machine proposed by the present invention can generate a higher average torque than the traditional alternating pole flux-reversal machine. At the same time, due to the magnetic field modulation effect, the torque ripple generated by the machine of the present invention is smaller than that of the traditional alternating pole flux-reversal machine.

[0080] The power factor calculation formula is as follows:

[0081]

[0082] Wherein, I s is the effective value of the current, ω e represents the electrical angular velocity, L s represents the synchronous inductance, and E is the amplitude of the back electromotive force. Based on the finite element method, the synchronous inductance (15.5 mh) of the V-type alternating pole flux reversal motor is higher than that of the traditional alternating pole flux reversal motor (14.4 mh). At the same copper loss (32 W), the power factor of the V-type alternating pole flux reversal motor is 0.55, while that of the traditional alternating pole flux reversal motor is 0.5. It is worth mentioning that due to the smaller effective air gap and higher synchronous inductance of the alternating pole motor, the power factors of both motors are lower than those of the traditional flux reversal motor. Nevertheless, due to the better magnetic flux concentrating effect of the V-type permanent magnet structure of the present invention, it has a larger back electromotive force, so it can have a higher power factor. As Figure 7 shown, it is the waveform diagram of the power factor of the two motors varying with the copper loss. It can be found that the power factor of the V-type alternating pole flux reversal motor at any copper loss is greater than that of the traditional alternating pole flux reversal motor.

[0083] Through the combination of optimized design and the finite element method, the performances of the two motors were compared in detail under the same conditions of the amount of permanent magnet used, motor size, number of coil turns, material, and rotational speed. As shown in Table 3, compared with the traditional alternating pole flux reversal motor, the V-type alternating pole flux reversal motor shows more excellent performance.

[0084] Table 3

[0085] Parameter CP-FRM V-CPFRM Back electromotive force 14.0V 17.2V Total harmonic distortion of back electromotive force (THD) 7.1％ 5.3％ Cogging torque 144.3mNm 36.8mNm Average torque 3.32Nm 3.74Nm Torque ripple 9.3％ 3.7％ Permanent magnet volume <![CDATA[15.88cm 3 > <![CDATA[15.88cm 3 > Average torque / Permanent magnet volume <![CDATA[209.1 kNm / m 3 > <![CDATA[235.5 kNm / m 3 > Power factor 0.5 0.55

[0086] Example 3:

[0087] Based on Examples 1 and 2, the topological structure of the V-type alternating pole flux reversal motor of the present invention is introduced in this example.

[0088] As Figure 8As shown in the figure, it is an alternating-pole flux-reversal permanent magnet motor with a V-shaped unequal-thickness permanent magnet. The motor includes a stator, a winding, a permanent magnet, and a rotor. The stator can be composed of several stator units combined in the circumferential direction. The stator has two adjacent stator teeth, and a set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N are inserted at the bottoms of the two adjacent stator teeth. The two permanent magnets in the V-shaped permanent magnet are magnetized inward. The winding is placed in the groove of the stator. The winding adopts a concentrated armature winding or a distributed armature winding. The winding is a single-layer winding or a double-layer winding. The number of stator grooves is twice the number of stator units. The stator unit has a set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N.

[0089] The two permanent magnets in the V-shaped permanent magnet are asymmetric. The two unequal-thickness permanent magnets 11 in the V-shaped structure have the same usage amount, but their widths and thicknesses are different. The central lines of the two V-shaped permanent magnets in a stator unit respectively have the same angle with the central line of the stator tooth where they are located, and the magnetic poles do not shift. The magnetic pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are the same. In order to reduce magnetic leakage, the two permanent magnets in a V-shaped structure are connected by a magnetic bridge.

[0090] As Figure 9 shown in the figure, it is an alternating-pole flux-reversal permanent magnet motor with a V-shaped magnetic pole offset. The distribution and structure of the stator, rotor, and winding of the motor are the same as those of the above Figure 8 motor structure. The stator can be composed of several stator units combined in the circumferential direction. The stator unit has two adjacent stator teeth, and a set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N are inserted at the bottoms of the adjacent stator teeth. The two permanent magnets in the V-shaped permanent magnet are magnetized inward. The difference is that the central lines of the two V-shaped permanent magnets in a stator unit respectively have different angles with the central line of the stator tooth where they are located, forming a magnetic pole offset angle 12, that is, the adjacent magnetic pole pairs are in an offset state. In order to reduce the magnetic leakage between poles, the two permanent magnets are connected by a magnetic bridge. The two permanent magnets have the same usage amount, width, and thickness. The magnetic pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are the same.

[0091] As Figure 10 shown in the figure, it is an alternating-pole flux-reversal permanent magnet motor with an adjacent magnetic pole asymmetric V-shaped angle. The distribution and structure of the stator, rotor, and winding of the motor are the same as those of the above Figure 8The motor structures are the same. The stator can be composed of several stator units combined in the circumferential direction. Each stator unit has two adjacent stator teeth, and a set of V-shaped permanent magnets arranged in the order of N-Fe-Fe-N are inserted at the bottom of the adjacent stator teeth. The two permanent magnets in the V-shaped permanent magnet are magnetized inward. The difference is that the pole opening angles of the adjacent V-shaped permanent magnets in a stator unit are asymmetric, forming an asymmetric V-shaped angle 13 between adjacent poles, that is, the V-shaped angles of a pair of adjacent V-shaped permanent magnets are different. The V-shaped angle is the angle formed between the two permanent magnets in a V-shaped permanent magnet. In order to reduce the interpolar leakage flux, the two permanent magnets are connected by a magnetic bridge. The amounts, widths and thicknesses of the two permanent magnets are the same. The angles between the center lines of the two V-shaped permanent magnets in a stator unit and the center lines of their respective stator teeth are the same, and the magnetic poles do not shift.

[0092] As Figure 11 shown, the topologies of the V-shaped alternating pole flux reversal motor and the traditional alternating pole flux reversal motor are compared in terms of average torque and torque ripple. It can be seen that the use of the V-shaped asymmetric structure can significantly improve the average torque of the motor and reduce the torque ripple. This is because, with the same amount of permanent magnets and motor volume, the V-shaped structure has a good magnetic focusing effect, which helps to improve the power density and torque density of the motor. At the same time, due to the harmonic cancellation effect of the asymmetric V-shaped structure and the magnetic isolation effect of the magnetic bridge, the cogging torque generated by the motor is low, and the no-load air-gap magnetic density fluctuation is small, which results in a low torque ripple of the motor.

[0093] As described above, this is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A V-type alternating pole flux-reversal permanent magnet motor, comprising a stator provided with windings and permanent magnets, and a rotor arranged inside the stator and coaxially assembled with the stator. Both the rotor and the stator adopt a double salient pole structure. The stator has stator slots, and the windings are arranged in the stator slots. The inner ring of the stator has stator teeth, and it is characterized in that, The stator is circumferentially provided with a plurality of stator units. Each stator unit includes two left and right stator teeth and two V-shaped permanent magnets. The polarities of the four single-piece permanent magnets that make up the two V-shaped permanent magnets are the same, and the iron pole shoes beside the permanent magnets automatically act as the other pole, thus forming an alternating pole structure. The two V-shaped permanent magnets in the stator unit are respectively arranged inside the left and right stator teeth.

2. The V-type alternating pole flux reversal permanent magnet machine according to claim 1, wherein The pole opening angles of the two V-shaped permanent magnets in the stator unit are the same, and the angles between the center lines of the two V-shaped permanent magnets and the center lines of the corresponding stator teeth are the same.

3. A V-type alternating pole flux-reversal permanent magnet machine according to claim 1, wherein The widths and thicknesses of the four single-piece permanent magnets that make up the two V-shaped permanent magnets in the stator unit are the same.

4. A V-type alternating pole flux-reversal permanent magnet machine according to claim 1, characterized in that, The alternating pole arrangement in the stator unit is N-Fe-Fe-N or N-Fe-N-Fe; and / or, the two single-piece permanent magnets that make up the V-shaped permanent magnet are connected by a magnetic bridge.

5. A V-type alternating pole flux-reversal permanent magnet machine according to claim 1, characterized in that, The relative positions of the V-shaped permanent magnets are determined by a position ratio, and the position ratio satisfies: P r ＝α / β In the formula, α represents the angle between the center of the stator tooth and the center of the V-shaped permanent magnet, and β represents the angle from the center line of the stator tooth to the edge of the stator tooth.

6. A V-shaped alternating pole flux-reversal permanent magnet motor according to claim 1, characterized in that, The two V-shaped permanent magnets in the stator unit are arranged asymmetrically.

7. A V-type alternating pole flux-reversal permanent magnet machine according to claim 6, characterized in that, The two single-piece permanent magnets that make up the V-shaped permanent magnet have the same amount, and their widths and thicknesses are different.

8. A V-type alternating pole flux-reversal permanent magnet machine according to claim 6, characterized in that The two single-piece permanent magnets that make up the V-shaped permanent magnet are in an offset state.

9. A V-type alternating pole flux reversal permanent magnet machine according to claim 6, characterized in that, The pole opening angles of the two V-shaped permanent magnets in the stator unit are asymmetric.

10. A V-type alternating pole flux-reversal permanent magnet machine according to claim 1, wherein The winding adopts a concentrated armature winding or a distributed armature winding; and / or, the winding is a single-layer winding or a double-layer winding; when the alternating pole arrangement in the stator unit is N-Fe-Fe-N, the number of pole pairs of the winding should satisfy: P = |iZ s / 2 ± Z r |, where i = 1, 2, 3… When the alternating pole arrangement in the stator unit is N-Fe-N-Fe, the number of pole pairs of the winding should satisfy: P = |iZ s ±Z r |, where i = 1, 2, 3… Wherein, P represents the number of pole pairs of the winding, i represents the order of the permanent magnet magnetic field harmonic, Z s represents the number of stator slots, and Z r represents the number of rotor slots.

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