Variable frequency speed regulation permanent magnet synchronous motor and driving device

Abstract

The utility model relates to a variable frequency speed regulation permanent magnet synchronous motor and a driving device, comprising a stator and twelve windings arranged on the stator in a central symmetry manner, and the windings can be electrically connected with a three-phase power supply; every four windings which are connected to the stator in a central symmetry mode form a winding unit. The frequency conversion speed regulation permanent magnet synchronous motor can be switched among a low-speed state, a medium-speed state and a high-speed state through the electric connection mode of the winding unit and the three-phase power supply. The variable-frequency permanent magnet synchronous motor has the advantages that by arranging the twelve windings and changing the series-parallel connection relation among the windings, connection between the windings and a three-phase power supply can be achieved, meanwhile, low-speed operation, medium-speed operation and low-speed operation of the variable-frequency permanent magnet synchronous motor can be achieved, and compared with the prior art, the variable-frequency permanent magnet synchronous motor can have an additional middle speed adjustment level; therefore, the flexibility of the variable-frequency permanent magnet synchronous motor is improved, and the matching degree of the variable-frequency permanent magnet synchronous motor to use scenes is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of permanent magnet synchronous motors, in particular to a variable frequency speed regulating permanent magnet synchronous motor and a driving device. Background Art

[0002] The permanent magnet synchronous motor includes a casing, a rotor and a stator. The rotor and the stator are coaxial and the rotor is sleeved inside the stator. The rotor is rotatably connected to the casing, and the stator is fixedly supported on the casing.

[0003] At the same time, permanent magnet synchronous motors also have speed regulation requirements. Currently, the solutions for adjusting the speed mainly include the following solutions:

[0004] The first option is to reduce the rated no-load back EMF of the motor, but this option will make the motor energy consumption ratio very uneconomical.

[0005] The second solution is to use IGBT (insulated gate bipolar transistor) that can withstand higher reverse voltage, but this solution greatly increases the system cost.

[0006] The third solution uses a complex rotor magnetic circuit structure, but this solution has complex electromagnetic simulation calculations and greatly increases the difficulty of the manufacturing process.

[0007] In order to overcome the above defects, the method disclosed in publication number CN214799253U can be adopted to realize two-stage regulation of the motor by changing the wiring form of the motor. However, in this form of motor speed regulation, the speed regulation range of the motor is narrow, and only low-speed regulation and high-speed speed regulation of the motor speed can be realized, but it does not have the ability of medium-speed regulation, and it is difficult to match complex motor operating conditions. Utility Model Content

[0008] 1. Technical issues to be resolved

[0009] In view of the above-mentioned shortcomings and deficiencies of the prior art, the utility model provides a variable frequency speed regulation permanent magnet synchronous motor, which solves the technical problems in the prior art that the speed regulation range of the motor is narrow, and can only achieve low-speed and high-speed speed regulation of the motor speed, but does not have the ability of medium-speed regulation, and is difficult to match complex motor operating conditions.

[0010] (II) Technical solution

[0011] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0012] In the first aspect, the utility model provides a variable frequency speed regulation permanent magnet synchronous motor, including a stator and twelve windings centrally symmetrically arranged on the stator, and the windings can be electrically connected to a three-phase power supply; every four windings centrally symmetrically connected to the stator form a winding unit; the electrical connection form between the winding unit and the three-phase power supply can enable the variable frequency speed regulation permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state; in the medium speed state, the two windings in each winding unit form a winding assembly, and the two ends of the two winding assemblies in each winding unit are correspondingly connected to form a first node and a second node, the three first nodes corresponding to the three winding unit pairs are correspondingly connected to the three-phase electricity of the three-phase power supply, and the three second nodes corresponding to the three winding unit pairs are connected in parallel with each other.

[0013] In a technical solution of the utility model, under low speed state, one end of the windings corresponding to the three winding units connected in series corresponds to the three-phase electricity of the three-phase power supply, and the other ends are connected in parallel.

[0014] In a technical solution of the utility model, in a high-speed state, all windings of each winding unit are connected in parallel with each other, one end of the three winding units is correspondingly connected to the three-phase electricity of the three-phase power supply, and the other ends are connected in parallel with each other.

[0015] In one technical solution of the utility model, the variable frequency speed regulation permanent magnet synchronous motor also includes a plurality of AC contactors, which are electrically connected to the windings and can switch between a connected state and a disconnected state, so that the electrical connection form between the winding unit and the three-phase power supply can enable the variable frequency speed regulation permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state.

[0016] In a technical solution of the utility model, the AC contactors are arranged in nine groups, and each group of AC contactors includes three AC contactors corresponding to the three winding units one by one; each winding unit includes a first winding, a second winding, a third winding and a fourth winding, and the fourth winding and the third winding, the third winding and the second winding, and the second winding and the first winding are electrically connected through the fourth group of AC contactors, the fifth group of AC contactors and the sixth group of AC contactors respectively; the head end of the first winding is electrically connected to one of the three-phase power supplies, and the tail end of the fourth winding is connected in parallel; one end of the first group of AC contactors is connected to the tail end of the first winding, one end of the second group of AC contactors is connected to the tail end of the second winding, one end of the third group of AC contactors is connected to the tail end of the third winding, and the other ends of the first group of AC contactors, the second group of AC contactors and the third group of AC contactors are electrically connected to the tail end of the fourth winding; the seventh group of AC contactors One end of the first, second, third, seventh, eighth and ninth groups of AC contactors are connected to the head end of the first winding, and the other ends of the seventh, eighth and ninth groups of AC contactors are connected to the tail end of the sixth, fifth and fourth groups of AC contactors, respectively; in the low-speed state, the first, second, third, seventh, eighth and ninth groups of AC contactors are switched to the connected state, and the fourth, fifth and sixth groups of AC contactors are switched to the disconnected state; in the medium-speed state, the first, third, fifth, seventh and ninth groups of AC contactors are switched to the connected state, and the second, eighth, fourth and sixth groups of AC contactors are switched to the disconnected state; in the high-speed state, the fourth, fifth and sixth groups of AC contactors are switched to the connected state, and the first, second, third, seventh, eighth and ninth groups of AC contactors are switched to the disconnected state.

[0017] In a technical solution of the utility model, the variable frequency speed regulation permanent magnet synchronous motor also includes a casing, a rotor and a rotating shaft. The rotor and the stator are coaxial and located inside the stator. The rotating shaft and the rotor are coaxial and fixedly connected. The stator is fixed in the casing, and the rotating shaft is rotatably connected in the casing.

[0018] In a technical solution of the utility model, it also includes magnetic poles, magnetic isolation sleeves, rotor drum brackets and magnets. The rotor drum bracket connects the rotating shaft and the rotor, the magnetic isolation sleeve is sleeved on the inner wall of the rotor, and the magnetic poles and magnets are embedded in the rotor at intervals along the circumference of the rotor.

[0019] In a second aspect, the utility model provides a driving device, including the variable frequency speed regulation permanent magnet synchronous motor in the above technical solution.

[0020] In a technical solution of the utility model, a control assembly is also included, and all AC contactors are arranged on the control assembly.

[0021] (III) Beneficial effects

[0022] The beneficial effect of the utility model is that the variable frequency speed regulation permanent magnet synchronous motor and drive device of the utility model, by setting twelve windings and changing the series-parallel connection relationship between the windings, can realize the connection of the windings with the three-phase power supply, and can also realize the low-speed, medium-speed and operation of the variable frequency permanent magnet synchronous motor. Compared with the prior art, it can provide an additional intermediate speed adjustment level, thereby improving the flexibility of the variable frequency permanent magnet synchronous motor and improving its matching degree with the usage scenario.

[0023] The above-mentioned winding and three-phase power supply electrical connection form provides a variable frequency speed regulation permanent magnet synchronous motor that can achieve three rated frequencies. By changing the series-parallel combination of the windings, the voltage balance during low, medium and high speed operation can be achieved, thereby solving the problems of weak magnetic speed regulation difficulty and high manufacturing cost of the prior art motor.

[0024] The utility model maintains voltage balance by connecting windings in series and parallel, forming three rated frequency points and motors with low, medium and high speeds, thereby realizing weak magnetic speed expansion. The drive device including the motor can also realize three-level speed regulation, and has good flexibility of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a circuit diagram of the electrical connection between the winding unit and the three-phase power supply in the medium speed state of the utility model;

[0026] Figure 2 This is a circuit diagram of the electrical connection between the winding unit and the three-phase power supply in the low-speed state of the utility model;

[0027] Figure 3 This is a circuit diagram of the electrical connection between the winding unit and the three-phase power supply in the high-speed state of the utility model;

[0028] Figure 4 It is the electrical connection circuit diagram of the winding, three-phase power supply and AC contactor of the utility model;

[0029] Figure 5 This is one of the structural schematic diagrams of the variable frequency speed regulation permanent magnet synchronous motor of the utility model;

[0030] Figure 6 This is the second structural schematic diagram of the variable frequency speed regulation permanent magnet synchronous motor of the utility model.

[0031] [Description of Reference Numerals]

[0032] 1: stator;

[0033] 2: Winding;

[0034] 3: Three-phase power supply;

[0035] 4: AC contactor;

[0036] 5: Casing;

[0037] 6: rotor;

[0038] 7: Rotating shaft;

[0039] 8: magnetic pole;

[0040] 9: Magnetic isolation sleeve;

[0041] 10: rotor reel support;

[0042] 11: Magnetic steel. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the following Figure 1-6 , the utility model is described in detail through specific implementation methods. Among them, the directional nouns such as "upper" and "lower" mentioned in this article are Figure 5 and Figure 6 The orientation is used as a reference.

[0044] Embodiment 1:

[0045] Reference Figure 1-Figure 6 The embodiment of the utility model provides a variable frequency speed regulation permanent magnet synchronous motor, comprising a stator 1 and twelve windings 2 centrally symmetrically arranged on the stator 1, and the windings 2 can be electrically connected to a three-phase power supply 3; every four windings 2 centrally symmetrically connected to the stator 1 form a winding unit; the electrical connection form between the winding unit and the three-phase power supply 3 can enable the variable frequency speed regulation permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state; in the medium speed state, the two windings 2 in each winding unit form a winding assembly, and the two ends of the two winding assemblies in each winding unit are correspondingly connected to form a first node and a second node, the three first nodes corresponding to the three winding unit pairs are correspondingly connected to the three-phase electricity of the three-phase power supply 3, and the three second nodes corresponding to the three winding unit pairs are connected in parallel with each other.

[0046] like Figure 1 In this embodiment, by setting twelve windings 2 and changing the series-parallel connection relationship between the windings 2, the connection between the windings 2 and the three-phase power supply 3 can be realized, and the medium-speed operation of the variable-frequency permanent magnet synchronous motor can be realized. Compared with the prior art, an additional intermediate speed adjustment level can be provided, thereby improving the flexibility of the variable-frequency permanent magnet synchronous motor.

[0047] like Figure 2 In the low speed state, one end of the windings 2 corresponding to the three winding units connected in series corresponds to the three-phase power of the three-phase power supply 3, and the other end is connected in parallel. Figure 3In the high-speed state, all windings 2 of each winding unit are connected in parallel with each other, one end of the three winding units is connected to the three-phase power of the three-phase power supply 3, and the other ends are connected in parallel with each other.

[0048] Furthermore, through the above-mentioned electrical connection form of the winding 2 and the three-phase power supply 3, the motor can also be switched to a low-speed state and a high-speed state, so that the variable frequency speed regulation permanent magnet synchronous motor can achieve three-level speed regulation, thereby further improving the use flexibility of the variable frequency speed regulation permanent magnet synchronous motor and improving its matching degree with the usage scenario.

[0049] Moreover, the electrical connection form of the above-mentioned winding 2 and the three-phase power supply 3 provides a variable frequency speed regulation permanent magnet synchronous motor that can achieve three rated frequencies. By changing the series-parallel combination form of the winding 2, the voltage balance during low, medium and high speed operation can be achieved, thereby solving the problems of difficult weak magnetic speed regulation of motors in the prior art and high manufacturing costs.

[0050] When the motor runs at the first rated frequency point, the speed is low, and the voltage is balanced. When the motor needs to run at medium speed, only the connection of winding 2 needs to be adjusted, and the motor speed can be increased from low speed to medium speed, and the voltage remains balanced when the medium speed is reached. When the motor needs to run at high speed, only the connection of winding 2 needs to be adjusted, and the motor speed can be increased from medium speed to high speed, and the voltage continues to remain balanced when the high speed is reached. Therefore, the utility model can make a motor have three frequency rated points, and achieve voltage balance at three rated speeds, such as low, medium, and high speed conversion, and finally achieve the purpose of weak magnetic speed expansion, so there is no need to increase the capacity of the inverter in the system, so as to easily achieve weak magnetic speed expansion.

[0051] The utility model maintains voltage balance by connecting the windings 2 in series and in parallel, forming a motor with three rated frequency points and low, medium and high speeds, thereby realizing weak magnetic field speed expansion.

[0052] The variable frequency speed regulating permanent magnet synchronous motor also includes a housing 5, a rotor 6 and a rotating shaft 7. The rotor 6 is coaxial with the stator 1 and is located inside the stator 1. The rotating shaft 7 is coaxial with the rotor 6 and is fixedly connected. The stator 1 is fixed in the housing 5, and the rotating shaft 7 is rotatably connected in the housing 5. It also includes a magnetic pole 8, a magnetic isolation sleeve 9, a rotor reel bracket 10 and a magnetic steel 11. The rotor reel bracket 10 connects the rotating shaft 7 and the rotor 6. The magnetic isolation sleeve 9 is sleeved on the inner wall of the rotor 6. The magnetic pole 8 and the magnetic steel 11 are embedded in the rotor 6 at intervals along the circumference of the rotor 6.

[0053] In this embodiment, the rotor 6 includes stacked punching sheets, which are I-shaped with upper and lower arc surfaces. The I-shaped slots of two adjacent magnetic poles 8 are filled with spaced N and S pole strip magnets 11, and the magnets 11 fill the entire magnetic pole 8.

[0054] When the magnetic field generated by the stator 1 interacts with the magnetic field generated by the rotor 6, the rotor 6 is caused to rotate; after the motor stator 1 is energized, a magnetic field will be generated around it; the rotor 6 will have an induced electromotive force generated in the magnetic field, and current will flow through the closed-loop rotor 6 circuit, and a magnetic field will also be formed around the rotor 6; when the two magnetic fields have the same polarity, repulsion will be generated; in the process of constantly changing the phase sequence of the stator 1 power supply of the motor, the magnetic field of the stator 1 is also constantly changing, thereby causing the motor to rotate continuously.

[0055] Embodiment 2:

[0056] Reference Figure 1-Figure 4 In addition to all the technical solutions of the above embodiments, the embodiments of the present utility model further have the following technical solutions:

[0057] like Figure 4The variable frequency speed regulation permanent magnet synchronous motor also includes a plurality of AC contactors 4, which are electrically connected to the winding 2 and can be switched between a connected state and a disconnected state, so that the electrical connection form between the winding unit and the three-phase power supply 3 can enable the variable frequency speed regulation permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state. The AC contactors 4 are arranged in nine groups, and each group of the AC contactors 4 includes three AC contactors 4 corresponding to the three winding units one by one; each winding unit includes a first winding, a second winding, a third winding and a fourth winding, and the fourth winding and the third winding, the third winding and the second winding, and the second winding and the first winding are electrically connected through the fourth group of AC contactors 4, the fifth group of AC contactors 4 and the sixth group of AC contactors 4; the head end of the first winding is electrically connected to one of the three-phase power supplies 3, and the tail end of the fourth winding is connected in parallel; one end of the first group of AC contactors 4 is connected to the tail end of the first winding, one end of the second group of AC contactors 4 is connected to the tail end of the second winding, one end of the third group of AC contactors 4 is connected to the tail end of the third winding, and the other ends of the first group of AC contactors 4, the second group of AC contactors 4 and the third group of AC contactors 4 are electrically connected to the tail end of the fourth winding; the seventh group of AC contactors 4, the eighth group of AC contactors 4 and the eighth group of AC contactors 4 are electrically connected to the tail end of the third winding. One end of the contactor 4 and the ninth group of AC contactors 4 are correspondingly connected to the head end of the first winding, and the other ends of the seventh group of AC contactors 4, the eighth group of AC contactors 4 and the ninth group of AC contactors 4 are respectively correspondingly connected to the tail end of the sixth group of AC contactors 4, the tail end of the fifth group of AC contactors 4, and the tail end of the fourth group of AC contactors 4; in the low-speed state, the first group, the second group, the third group, the seventh group, the eighth group and the ninth group of AC contactors 4 are switched to the connected state, and the fourth group, the fifth group and the sixth group of AC contactors 4 are switched to the disconnected state; in the medium-speed state, the first group, the third group, the fifth group, the seventh group and the ninth group of AC contactors 4 are switched to the connected state, and the second group, the eighth group, the fourth group and the sixth group of AC contactors 4 are switched to the disconnected state; in the high-speed state, the fourth group, the fifth group and the sixth group of AC contactors 4 are switched to the connected state, and the first group, the second group, the third group, the seventh group, the eighth group and the ninth group of AC contactors 4 are switched to the disconnected state.

[0058] In this embodiment, nine groups of AC contactors 4 can be used to achieve the state switching of the motor through the above-mentioned electrical connection form, so there is no need to perform complicated wiring work every time the speed is adjusted, thereby improving the convenience of the motor speed regulation and the flexibility of the motor speed regulation.

[0059] Specifically, for ease of understanding, the winding 2, the nodes at both ends of the winding 2, and the AC contactor 4 are defined as follows:

[0060] The four windings 2 in a winding unit are respectively denoted as L1, L2, L3 and L4;

[0061] The winding unit corresponding to the U phase in the three-phase power supply is recorded as the U winding, and the nodes at both ends of L1, L2, L3 and L4 in the U winding are (U1, X1), (U2, X2), (U3, X3) and (U4, X4) respectively;

[0062] The winding unit corresponding to the V phase in the three-phase power supply is recorded as V winding, and the nodes at both ends of L1, L2, L3 and L4 in the V winding are (V1, Y1), (V2, Y2), (V3, Y3) and (V4, Y4) respectively;

[0063] The winding unit corresponding to the W phase in the three-phase power supply is recorded as the W winding, and the nodes at both ends of L1, L2, L3 and L4 in the W winding are (W1, Z1), (W2, Z2), (W3, Z3) and (W4, Z4) respectively;

[0064] Among them, (U1, X1), (V1, Y1), and (W1, Z1) correspond to the beginning and the end of L1 in the three winding units respectively;

[0065] (U2, X2), (V2, Y2), (W2, Z2) correspond to the beginning and the end of L2 in the three winding units respectively;

[0066] (U3, X3), (V3, Y3), (W3, Z3) correspond to the beginning and the end of L3 in the three winding units respectively;

[0067] (U4, X4), (V4, Y4), and (W4, Z4) correspond to the beginning and the end of L4 in the three winding units respectively.

[0068] The nine groups of AC contactors are marked as KM1 to KM9 in sequence;

[0069] When the motor is in the low speed state, U1, V1, and W1 are connected to the three-phase power supply respectively, X1 is connected to U2, X2 is connected to U3, and X3 is connected to U4; Y1 is connected to V2, Y2 is connected to V3, and Y3 is connected to Y4; Z1 is connected to W2, Z2 is connected to W3, and Z3 is connected to W4; X4, Y4, and Z4 are connected into a star point, KM1, KM2, KM3, KM7, KM8, and KM9 are in a connected state, and KM4, KM5, and KM6 are in a disconnected state.

[0070] At medium speed of the motor, (U1, U3), (V1, V3), (W1, W3) are connected to three-phase power supply respectively; X1 is connected to U2, X3 is connected to U4; Y1 is connected to V2, Y3 is connected to V4; Z1 is connected to W2, Z3 is connected to W4;

[0071] X2, X4, Y2, Y4, Z2, and Z4 are connected to form a star point, KM1, KM3, KM5, KM7, and KM9 are in a connected state, and KM2, KM8, KM4, and KM6 are in a disconnected state.

[0072] When the motor is in the high-speed state, (U1, U2, U3, U4), (V1, V2, V3, V4), and (W1, W2, W3, W4) are connected to the three-phase power supply respectively; X1, X2, X3, X4, Y1, Y2, Y3, Y4, Z1, Z2, Z3, Z4 are connected into a star point, KM4, KM5, KM6 are in the connected state, and KM1, KM2, KM3, KM7, KM8, and KM9 are in the disconnected state.

[0073] Embodiment 3:

[0074] The embodiment of the utility model provides a driving device, which, in addition to including the variable frequency speed regulating permanent magnet synchronous motor in the above embodiment 2, further has the following technical solutions:

[0075] It also includes a control assembly, and all AC contactors are arranged on the control assembly.

[0076] In this embodiment, the motor is used in a drive device, which can be a drive device for a machine tool, a drive device for an electric vehicle, etc. All AC contactors are integrated in the control assembly, thereby improving the speed regulation convenience of the drive device. The drive device including the motor can also achieve three-level speed regulation and has good flexibility in use.

[0077] Specifically, the control form of the AC contactor can be manual control or electrical control.

[0078] More specifically, when the AC contactor is manually controlled, the control assembly may be configured as a switch box.

[0079] It can be understood that, except for any conflicting parts, the above-mentioned embodiments 1-3 can be freely combined to form other implementation methods of the present utility model.

[0080] In the description of the present utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0081] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the present utility model, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0083] The term "comprise" or any other similar term is intended to cover a non-exclusive inclusion, such that a process, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article, or apparatus / device.

[0084] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A variable frequency speed regulating permanent magnet synchronous motor, characterized in that: It comprises a stator (1) and twelve windings (2) centrally symmetrically arranged on the stator (1), wherein the windings (2) can all be electrically connected to a three-phase power supply (3); Every four windings (2) centrally symmetrically connected to the stator (1) form a winding unit; the electrical connection between the winding unit and the three-phase power supply (3) enables the variable frequency speed regulation permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state; In the medium speed state, the two windings (2) in each winding unit form a winding assembly, the two ends of the winding assembly in each winding unit are correspondingly connected to form a first node and a second node, the three first nodes corresponding to the three winding unit pairs are correspondingly connected to the three-phase electricity of the three-phase power supply (3), and the three second nodes corresponding to the three winding unit pairs are connected in parallel.

2. The variable frequency speed regulating permanent magnet synchronous motor according to claim 1, characterized in that: In the low-speed state, the windings (2) corresponding to the three winding units are connected in series with one end correspondingly connected to the three-phase power of the three-phase power supply (3), and the other ends are connected in parallel.

3. The variable frequency speed regulating permanent magnet synchronous motor according to claim 2, characterized in that: In the high-speed state, all the windings (2) of each winding unit are connected in parallel with each other, one end of the three winding units is correspondingly connected to the three-phase power of the three-phase power supply (3), and the other ends are connected in parallel with each other.

4. The variable frequency speed regulating permanent magnet synchronous motor according to claim 3, characterized in that: The variable frequency speed regulating permanent magnet synchronous motor further comprises a plurality of AC contactors (4), wherein the AC contactors (4) are electrically connected to the winding (2) and can be switched between a connected state and a disconnected state, so that the electrical connection form between the winding unit and the three-phase power supply (3) can enable the variable frequency speed regulating permanent magnet synchronous motor to switch between a low speed state, a medium speed state and a high speed state.

5. The variable frequency speed regulating permanent magnet synchronous motor according to claim 4, characterized in that: The AC contactors (4) are arranged in nine groups, and each group of the AC contactors (4) comprises three AC contactors (4) corresponding one-to-one to the three winding units; Each of the winding units comprises a first winding, a second winding, a third winding and a fourth winding, and the fourth winding and the third winding, the third winding and the second winding, and the second winding and the first winding are electrically connected via the fourth group of AC contactors (4), the fifth group of AC contactors (4) and the sixth group of AC contactors (4) respectively; The head ends of the first windings are electrically connected to one phase of the three-phase power supply (3), and the tail ends of the fourth windings are connected in parallel; One end of the AC contactor (4) of the first group is connected to the tail end of the first winding, one end of the AC contactor (4) of the second group is connected to the tail end of the second winding, one end of the AC contactor (4) of the third group is connected to the tail end of the third winding, and the other ends of the AC contactors (4) of the first group, the AC contactors (4) of the second group and the AC contactors (4) of the third group are all electrically connected to the tail end of the fourth winding; One end of the AC contactors (4) of the seventh group, the AC contactors (4) of the eighth group and the AC contactors (4) of the ninth group are all correspondingly connected to the head end of the first winding, and the other ends of the AC contactors (4) of the seventh group, the AC contactors (4) of the eighth group and the AC contactors (4) of the ninth group are respectively correspondingly connected to the tail end of the AC contactors (4) of the sixth group, the tail end of the AC contactors (4) of the fifth group and the tail end of the AC contactors (4) of the fourth group; In the low-speed state, the AC contactors (4) of the first, second, third, seventh, eighth and ninth groups are switched to the connected state, and the AC contactors (4) of the fourth, fifth and sixth groups are switched to the disconnected state; In the medium speed state, the AC contactors (4) of the first, third, fifth, seventh and ninth groups are switched to the connected state, and the AC contactors (4) of the second, eighth, fourth and sixth groups are switched to the disconnected state; In the high-speed state, the AC contactors (4) of the fourth, fifth and sixth groups are switched to the connected state, and the AC contactors (4) of the first, second, third, seventh, eighth and ninth groups are switched to the disconnected state.

6. The variable frequency speed regulating permanent magnet synchronous motor according to claim 5, characterized in that: The variable frequency speed regulating permanent magnet synchronous motor further comprises a casing (5), a rotor (6) and a rotating shaft (7); the rotor (6) and the stator (1) are coaxial and located inside the stator (1); the rotating shaft (7) and the rotor (6) are coaxial and fixedly connected; the stator (1) is fixed inside the casing (5); and the rotating shaft (7) is rotatably connected inside the casing (5).

7. The variable frequency speed regulating permanent magnet synchronous motor according to claim 6, characterized in that: It also comprises a magnetic pole (8), a magnetic isolation sleeve (9), a rotor drum support (10) and a magnetic steel (11), wherein the rotor drum support (10) is connected to the rotating shaft (7) and the rotor (6), the magnetic isolation sleeve (9) is sleeved on the inner wall of the rotor (6), and the magnetic pole (8) and the magnetic steel (11) are embedded in the rotor (6) at intervals along the circumference of the rotor (6).

8. A driving device, characterized in that: It includes the variable frequency speed regulation permanent magnet synchronous motor as described in claim 6 or 7.

9. The driving device according to claim 8, characterized in that: It also comprises a control assembly, on which all the AC contactors (4) are arranged.

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