CN109861477B - Permanent magnet/reluctance double-rotor low-speed high-torque synchronous motor and control system thereof - Google Patents

Abstract

Permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor and its control system. The synchronous motor is mainly composed of an outer rotor (1), an inner rotor (2) and a stator (3); the stator (3) is arranged on the outer rotor (1) ) and the inner rotor (2); this method obtains the entire rotor position by estimating the position of the reluctance rotor, thereby achieving position sensorless control. The proposed position sensorless vector control method does not require coordinate transformation, has a simple structure, and overcomes the complexity of traditional vector control and its strong dependence on motor parameters.

Description

Permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor and its control system

Technical areas:

The invention relates to a permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor and its control system. Belongs to the field of motor design and its control system.

Background technique:

There are a large number of equipment in modern industry that require low-speed and high-torque transmission systems, such as CNC machine tools, heavy mining machinery, oil drilling machinery, large industrial conveyor belts, and lifting equipment. Such systems are typical high-energy-consuming electromechanical equipment that consume Electricity accounts for approximately 10% of total industrial power consumption. At present, most of my country's low-speed and high-torque transmission equipment adopts the driving method of "conventional speed motor + reduction gear mechanism". However, the extra reduction transmission link will not only make the drive system bulky, increase maintenance costs, and reduce system reliability and operating efficiency. (The efficiency of the entire transmission chain is generally 75% to 85%), and redundant gear mechanisms will also bring about technical difficulties in processing, manufacturing, transportation and assembly, etc., as well as problems such as lubricating oil leakage and noise pollution. Therefore, Eliminating the direct drive method of the reduction gear mechanism is an inevitable choice for the future development of high-end mechanical equipment and improving the overall performance of the transmission system.

Permanent magnet synchronous motors have developed rapidly in recent years, and research work at home and abroad is also extremely active. Because whether operating as electric or power generation, permanent magnet synchronous motors have simple structures compared with induction motors, electric excitation synchronous motors and switched reluctance motors. , brushless reliability, high efficiency and power factor, large starting torque, wide economic operating range and other outstanding excellent properties, so it has been widely promoted and applied in many fields, especially in low-speed and high-torque direct drive systems. The prospects are very bright. In order to improve the torque density, make full use of the larger inner cavity space of the low-speed and high-torque direct-drive permanent magnet synchronous motor, and reduce its cost, it is an important development trend to develop new permanent magnet synchronous motor structures and new rotor structures. In addition, low-speed and high-torque direct-drive permanent magnet synchronous motors often operate under various complex working conditions such as variable load and heavy load. Therefore, a speed control method with strong pertinence, fast response speed and strong robustness is needed to control the speed. The performance improvement of high-end equipment has very important practical significance.

Contents of the invention

Purpose of the invention: The present invention provides a permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor and its control system. Its purpose is to solve the problems of poor system reliability and low operating efficiency in the reduction transmission link of traditional low-speed high-torque transmission equipment. , high cost and other issues. At the same time, the present invention adopts a dual-rotor structure design, which can increase the torque density and reduce the cost of the motor.

Technical solution: The present invention adopts the following technical solution:

A permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor is characterized in that: the synchronous motor is mainly composed of an outer rotor (1), an inner rotor (2) and a stator (3); the stator (3) is arranged on the outer rotor (1) ) and the inner rotor (2);

The inner rotor (2) includes a magnetic isolation ring (7) and a magnetic barrier reluctance rotor structure (6). The magnetic barrier reluctance rotor structure (6) is composed of a magnetic permeable layer (6-1) and a non-magnetic permeable layer ( 6-2) A structure composed of alternating phases. Each magnetic barrier type reluctance rotor structure (6) is fixed on the outer wall of the magnetic isolation ring (7) through a dovetail groove. The magnetic barrier type reluctance rotor structure (6) is arranged on the magnetic isolation ring. Between (7) and stator (3);

A permanent magnet (4) is provided inside the outer rotor (1);

The inner and outer surfaces of the stator (3) are evenly slotted, and a set of three-phase symmetrical windings are respectively embedded in the inner and outer surface slots of the stator (3) (this means that the windings in all slots are collectively referred to as a set of three-phase symmetrical windings. Windings, in fact, there are only two sets of windings combined inside and outside.), the windings in the inner and outer stator slots are connected in series or parallel to form the total stator winding of the motor.

The magnetic permeable layer (6-1) and the non-magnetic permeable layer (6-2) in the magnetic barrier reluctance rotor structure (6) both adopt a U-shaped structure (the U-shaped structure is named after the shape of the magnetic barrier reluctance rotor) ); the magnetic barrier type reluctance rotor structure (6) is composed of alternating magnetic permeable layers (6-1) and non-magnetic permeable layers (6-2), and the magnetic permeable layers (6-1) are connected by connecting ribs (6-3) are connected, and a non-magnetic layer (6-2) is formed between the two adjacent magnetic permeable layers (6-1).

The width of the connecting ribs (6-3) only needs to meet the mechanical strength conditions.

The magnetic permeable layer (6-1) has a structure with a gradually increasing width from the middle to both sides. (That is to say, the width gradually increases from the inside to the outside. As shown in Figure 3, the width of the innermost layer is narrow, then the width of the innermost layer and the outer layer of the innermost layer is wider than the innermost layer, and then, the width of the outer layer of the innermost layer is wider than that of the innermost layer. Then, the width of the outer layer of the innermost layer is narrower. The width of the inner layer is wider than that of the next inner layer, and the function of this structure has been explained in conjunction with Figure 3 in the specific implementation mode. Its function is as follows: the widths of each magnetically permeable layer (6-1) in the magnetic barrier are different. , combined in such a way that the thickness decreases from both sides to the middle, so that more magnetic flux flows through the magnetic permeable layer (6-1) on both sides of the magnetic barrier and less in the middle, which distributes the magnetic flux more reasonably and better limits the magnetic flux. The magnetic flux path reduces the harmonic content in the air gap magnetic field, improves the sinusoidality of the motor's air gap magnetic field, reduces the torque ripple, and improves the performance of the motor.)

Each pole of the permanent magnet (4) inside the outer rotor (1) adopts a multi-block anisotropic magnetization method, that is, each pole of the permanent magnet is divided into multiple blocks, each block is a region, and multiple regions can be formed, and each region The angle between the magnetizing direction and the radial direction of the outer rotor (1) gradually decreases from both sides to the middle, (as shown in Figure 4, the vertical arrow direction in the middle is the radial direction of the outer rotor; the permanent magnet (4) is surface-mounted on the inner surface of the outer rotor (1).

In order to better match the inner and outer rotors with the stator, the outer surface of the stator (3) adopts a fractional slot structure, and the inner surface of the stator (3) adopts a distributed winding structure.

The outer rotor (1) adopts a cup-shaped structure (the mechanical structure connecting the outer rotor is shaped like a cup, and the cup-shaped structure is often named) and is connected to the bearing, and the inner and outer rotors are coaxially connected. (The outer rotor (1) and the inner rotor are connected to the output bearing)

The position sensorless control strategy applied to the above-mentioned permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor and its control system is characterized by:

By estimating the position of the magnetic barrier reluctance rotor structure (6), the position of the entire rotor (the entire rotor here refers to the outer rotor (1) and the inner rotor (2)) is obtained, thereby achieving position sensorless control. First, the rotor position estimation module (15) (the rotor position estimation module is implemented in the controller, not in the motor) obtains the rotor position estimation value and the rotation speed estimation value, and combines the rotor position estimation value and the rotation speed estimation value. The measured values are compared with the rotor position given value and the speed given value respectively to obtain the rotor position error value and speed error value. The rotor position error value and speed error value are passed through the position regulator (8) and speed regulator (9) respectively. The speed given value and the torque given value are obtained. At the same time, the actual output torque of the motor is obtained by the stator current space vector calculation module (16) and the torque calculation module (17). The calculated actual output torque of the motor is input to The torque regulator (10) uses the output signal of the torque regulator (10) as the input signal of the three-phase current reference value calculation module (11), thereby obtaining the given value of the three-phase stator current, and finally passes the current regulator (12) Obtain the control signal of the current controllable PWM inverter (13) to control the new synchronous motor of the present invention.

Advantages and effects:

The new type of permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor of the present invention has a U-shaped reluctance structure with alternating magnetic conductive layers and non-magnetic conductive layers on the outside of the inner rotor, and the inner side of the outer rotor is surface-mounted with block magnetized permanent magnets in opposite directions. magnet. The motor adopts a single stator structure. The inner and outer surfaces of the stator are evenly slotted. There is a set of three-phase windings in the inner and outer stator slots, and the two sets of windings are connected in series or parallel to form the total stator winding of this type of motor. The outer surface of the stator adopts a fractional slot structure, and the inner surface of the stator adopts a distributed winding structure. The outer rotor is connected to the bearing using a cup-shaped structure, and the inner and outer rotors are coaxially connected.

The new permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor of the present invention adopts a position sensorless vector control method, and obtains the entire rotor position by estimating the position of the reluctance rotor, thereby achieving position sensorless control. The rotor position estimation value and the speed estimation value are obtained from the rotor position estimation module. The rotor position estimation value and the speed estimation value are compared with the rotor position given value and the speed given value respectively, and the rotor position error value and The speed error value, rotor position error value and speed error value are obtained through the position regulator and speed regulator respectively to obtain the speed given value and torque given value. At the same time, the actual value of the motor is obtained by the stator current space vector calculation module and torque calculation module. To output torque, input the calculated actual output torque of the motor to the torque regulator, and use the output signal of the torque regulator as the input signal of the three-phase current reference value calculation module to obtain the given value of the three-phase stator current. , and finally the control signal of the current-controlled PWM inverter is obtained through the current regulator to control the new synchronous motor of the present invention.

This kind of motor adopts a double-rotor single-stator structure, making full use of the large inner cavity space of the low-speed and high-torque direct-drive synchronous motor, greatly improving the torque density and material utilization of the motor, and can greatly reduce the energy consumption under the same power. The size and weight of the motor. Without considering changes in heat dissipation conditions, the torque density of a dual-rotor single-stator motor can be increased by about 40% compared with a conventional single-stator-rotor motor; or in other words, at the same power, the motor volume can be reduced by about 30%. The new permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor of the present invention not only has a reliable structure, low cost, and high efficiency, but also has outstanding advantages such as high torque density, high mechanical integration, and high utilization rate of motor structural materials.

The new dual-rotor motor of the present invention not only has the advantages of the traditional permanent magnet-assisted reluctance rotor motor, but also makes the permanent magnet and reluctance structures relatively independent, solving the problem that the permanent magnet-assisted reluctance rotor motor has many design parameters and is difficult to optimize. problem, the design method is more flexible; the demand for permanent magnets and magnetic performance requirements of the motor are greatly reduced, and the cost of the motor is reduced; the motor can produce electromagnetic torque and reluctance torque at the same time, improving the torque density of the motor, and The two torques are independent of each other, which greatly enhances the flexibility of the control method, improves the motor's torque density, efficiency, field-weakening speed regulation capability and inverter utilization.

The magnetic permeable layer and the non-magnetic permeable layer on the reluctance rotor of the present invention adopt a U-shaped structure, which is equivalent to increasing the air gap on the quadrature axis of the motor, thereby increasing the quadrature axis reluctance, which is beneficial to increasing the reluctance torque of the motor; each The magnetic barrier structure adopts a structure in which the thickness of the magnetic permeable layer gradually decreases from the middle to both sides, which improves the modulation effect of the magnetic barrier structure on the magnetic field, improves the sinusoidal nature of the air gap magnetic field between the inner stator and the rotor, and reduces harmonics. wave content; the permanent magnets on the outer rotor adopt block anisotropic magnetization, which not only makes the permanent magnet magnetic field near the air gap more concentrated, but also makes the motor air gap flux density distribution closer to sinusoidal, with less harmonic content , the magnetic density distribution is more uniform, and the salient pole effect of the motor rotor can be further enhanced, thereby improving the output electromagnetic torque capability and the utilization rate of the permanent magnets. The outer side of the stator matches the surface-mounted permanent magnets of the outer rotor. In order to solve the contradiction of low motor speed, large number of pole pairs and limited number of slots, the outer side of the stator adopts a fractional slot structure and utilizes the equivalent distribution effect of fractional slot windings. And weaken the tooth harmonic back electromotive force to achieve the effect of improving the potential waveform and increasing the winding utilization rate. The inner side of the stator matches the inner rotor reluctance structure. In order to reduce the harmonic content of the motor, increase the reluctance torque, and improve the sinusoidal back electromotive force, a distributed winding structure is adopted on the inner side of the stator.

The control method adopts a highly responsive and robust position sensorless vector control method based on the stator current space vector. This method obtains the entire rotor position by estimating the reluctance rotor position, thereby achieving position sensorless control. The proposed position sensorless vector control method does not require coordinate transformation, has a simple structure, and overcomes the complexity of traditional vector control and its strong dependence on motor parameters.

Description of drawings

Figure 1 is a schematic structural diagram of a permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor of the present invention;

Figure 2 is a schematic structural diagram of the inner rotor of the permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor of the present invention;

Figure 3 is a schematic diagram of a single magnetic barrier; 6. Magnetic barrier type reluctance rotor structure; 6-1. Magnetic permeable layer; 6-2. Non-magnetic permeable layer; 6-3. Connecting ribs;

Figure 4 is a schematic diagram of permanent magnets arranged in blocks with different magnetization;

Figure 5 is a functional block diagram of the position sensorless vector control of the permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor of the present invention.

Explanation of reference symbols:

1. Outer rotor; 2. Inner rotor; 3. Stator; 4. Permanent magnet; 5. Stator slot; 6. Magnetic barrier reluctance rotor structure; 6-1. Magnetic permeable layer; 6-2. Non-magnetic permeable layer ; 6-3. Connecting ribs; 7. Magnetic isolation ring; 8. Position regulator; 9. Speed regulator; 10. Torque regulator; 11. Three-phase current reference value calculation module; 12. Current regulator; 13 .Current controllable PWM inverter; 14. Three-phase rectifier; 15. Rotor position estimation module; 16. Stator current space vector calculation module; 17. Torque calculation module.

Detailed ways

A permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor is characterized in that: the synchronous motor is mainly composed of an outer rotor (1), an inner rotor (2) and a stator (3); the stator (3) is arranged on the outer rotor (1) ) and the inner rotor (2);

The inner rotor (2) includes a magnetic isolation ring (7) (2-1) and a magnetic barrier reluctance rotor structure (6). The magnetic barrier reluctance rotor structure (6) is composed of a magnetic permeable layer (6-1) and A structure composed of alternating non-magnetic conductive layers (6-2), each magnetic barrier reluctance rotor structure (6) is fixed on the outer wall of the magnetic isolation ring (7) through a dovetail groove, and the magnetic barrier reluctance rotor structure (6) is provided Between the magnetic isolation ring (7) and the stator (3);

A permanent magnet (4) is provided inside the outer rotor (1);

The inner and outer surfaces of the stator (3) are evenly slotted, and a set of three-phase symmetrical windings are respectively embedded in the inner and outer surface slots of the stator (3). The windings in the inner and outer stator slots are connected in series or parallel to form The total stator winding of this motor.

The magnetic permeable layer (6-1) and the non-magnetic permeable layer (6-2) in the magnetic barrier type reluctance rotor structure (6) both adopt a U-shaped structure; the magnetic barrier type reluctance rotor structure (6) consists of a magnetic permeability layer (6-1) and non-magnetic conductive layers (6-2) alternate with each other. The magnetic conductive layers (6-1) are connected through connecting ribs (6-3). The two adjacent magnetic conductive layers (6 -1) to form a non-magnetic conductive layer (6-2).

The width of the connecting ribs (6-3) only needs to meet the mechanical strength conditions.

The magnetic permeable layer (6-1) has a structure with a gradually increasing width from the middle to both sides.

The permanent magnets (4) inside the outer rotor (1) are permanent magnets that are magnetized in different directions in blocks, that is, each permanent magnet is divided into multiple areas, and the magnetization direction of each area is from both sides to the middle and the angle between the vertical direction. gradually decreases, (as shown in Figure 4, the direction of the vertical arrow in the middle is the radial direction of the outer rotor; the permanent magnet (4) is surface-attached to the inner surface of the outer rotor (1).

In order to better match the inner and outer rotors with the stator, the outer surface of the stator (3) adopts a fractional slot structure, and the inner surface of the stator (3) adopts a distributed winding structure.

The outer rotor (1) adopts a cup-shaped structure to be connected to the bearing, and the inner and outer rotors are coaxially connected.

The invention proposes a permanent magnet/reluctance dual-rotor low-speed and high-torque synchronous motor, as shown in Figure 1. It is characterized in that: the motor consists of an outer rotor 1, an inner rotor 2, and a stator 3. The inner and outer surfaces of the stator 3 are evenly slotted, and a set of three-phase windings are embedded in the slots on the inner and outer surfaces of the stator 3, and the two sets of windings are connected in series or parallel to form the total stator winding of the motor. The outer rotor 1 matches the surface-mounted permanent magnets 4 on the outside of the stator. In order to solve the contradiction of low motor speed, large number of pole pairs and limited slot number, the outer surface of the stator adopts a fractional slot structure. At the same time, the equivalent distribution effect of the fractional slot winding and the weakening effect of the tooth harmonic back electromotive force are used to achieve To achieve the effect of improving the potential waveform and increasing the winding utilization rate. The inner rotor 2 matches the reluctance structure inside the stator. In order to reduce the harmonic content of the motor, increase the reluctance torque, and improve the sinusoidality of the back electromotive force, the inner surface of the stator adopts a distributed winding structure.

Figure 2 is a schematic structural diagram of the inner rotor of the permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor of the present invention. The inner rotor has a U-shaped magnetic barrier structure with a magnetic permeable layer 6-1 and a non-magnetic permeable layer 6-2 alternately. The independent magnetic barriers are secured with dovetail grooves. The outer rotor of the dual-rotor motor adopts a permanent magnet structure, and the inner rotor adopts a reluctance structure. This allows the motor to have the advantages of a permanent magnet-assisted reluctance rotor motor, but also makes the permanent magnet and reluctance structures relatively independent, solving the problem of permanent magnet auxiliary magnets. The resistance rotor motor has many design parameters and is difficult to optimize. The design method is more flexible; it greatly reduces the motor's demand for permanent magnets and magnetic performance requirements, and reduces the cost of the motor; the motor can produce electromagnetic torque and reluctance rotation at the same time. torque, which improves the torque density of the motor, and the two torques are independent of each other, which greatly enhances the flexibility of the control method, improves the motor's torque density, efficiency, field-weakening speed regulation capability and inverter utilization.

Figure 3 is a schematic diagram of a single magnetic barrier structure. The magnetic barrier structure is composed of U-shaped magnetic permeable layers 6-1 and non-magnetic permeable layers 6-2 alternating with each other. The magnetic permeable layers 6-1 are connected through connecting ribs 6-3 to form a unified whole. Under the condition that the mechanical strength is met, the connecting ribs 6-3 should be as narrow as possible, which will better restrict the flow of magnetic flux along the prescribed path, thereby improving the energy conversion efficiency of the motor. In addition, the magnetic permeable layers in the magnetic barrier have different widths and are combined in such a way that the thickness decreases from both sides to the middle, so that more magnetic flux flows through the magnetic permeable layers on both sides of the magnetic barrier and less in the middle. The magnetic flux is reasonably distributed, the magnetic flux path is better limited, the harmonic content in the air gap magnetic field is reduced, the sinusoidality of the motor air gap magnetic field is improved, the torque ripple is reduced, and the performance of the motor is improved.

Figure 4 is a schematic diagram of permanent magnets arranged in blocks with anisotropic magnetization. The same permanent magnet is divided into different areas, and the magnetization methods of each area are different. That is, the magnetization direction of each area adopts a method in which the angle between the two sides and the vertical direction gradually decreases. This can not only make the permanent magnet magnetic field near the air gap more concentrated, make the motor air gap flux density distribution closer to sinusoidal, have less harmonic content, and make the magnetic density distribution more uniform, but can also further enhance the salient pole effect of the motor rotor. This further improves the output electromagnetic torque capability and permanent magnet utilization. In addition, it can also effectively reduce cogging torque and suppress torque pulsation.

The present invention proposes a position sensorless vector control method for a permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor. As shown in Figure 5, the entire position of the magnetic barrier reluctance rotor structure (6) is estimated to obtain rotor position, thereby enabling position sensorless control. The position sensorless vector control method of the present invention does not require coordinate transformation, has a simple structure, and overcomes the complexity of traditional vector control and the strong dependence on motor parameters.

The output torque of the new synchronous motor of the present invention is the superposition of the interaction results between the internal and external rotor and the stator magnetic field. Since the salient pole of the reluctance rotor synchronous motor is relatively large, it is easy to estimate the rotor position. Therefore, the present invention estimates the reluctance rotor position. To obtain the entire rotor position, thereby achieving position sensorless control. Input the detected three-phase current value of the stator into the rotor position estimation module 15 to obtain the estimated rotor position value and the estimated speed value. Subtract the estimated rotor position value from the given rotor position value to obtain the rotor position error value. Input the rotor position error value to the position regulator 8 to obtain the speed given value. Subtract the estimated speed value from the given speed value to obtain the speed error value. Input the speed error value to the speed regulator 9 to obtain the torque given value. fixed value, and at the same time, input the detected three-phase current value of the stator into the stator current space vector calculation module 16 to obtain the amplitude and space electrical angle of the stator current space vector, and calculate the actual output torque of the motor through the torque calculation module 17, Subtract the actual output torque from the torque given value to obtain the motor torque error value. Input the motor torque error value to the torque regulator 10 to obtain the stator current space vector given value. The stator current space vector is given The value and the initial phase of the three-phase current are input into the three-phase current given value calculation module 11, thereby obtaining the given value of the three-phase stator current. Finally, the three-phase stator current detection value is subtracted from the three-phase stator current given value to obtain the three-phase stator current detection value. The phase stator current error value is input to the current regulator 12 to obtain the control signal of the current controllable PWM inverter 13 to control the new synchronous motor of the present invention. The position sensorless vector control method of the present invention does not require coordinate transformation, has a simple structure, and overcomes the complexity of traditional vector control and the strong dependence on motor parameters.

Claims (1)

1. A position sensorless control strategy using a permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor, which is characterized by: Permanent magnet/reluctance dual-rotor low-speed high-torque synchronous motor, the synchronous motor is mainly composed of an outer rotor (1), an inner rotor (2) and a stator (3); the stator (3) is arranged on the outer rotor (1) and the inner rotor (2) between; The inner rotor (2) includes a magnetic isolation ring (7) and a magnetic barrier reluctance rotor structure (6). The magnetic barrier reluctance rotor structure (6) is composed of a magnetic permeable layer (6-1) and a non-magnetic permeable layer ( 6-2) A structure composed of alternating arrangements. Each magnetic barrier type reluctance rotor structure (6) is fixed on the outer wall of the magnetic isolation ring (7) through a dovetail groove. The magnetic barrier type reluctance rotor structure (6) is set on the magnetic isolation ring. Between (7) and stator (3); A permanent magnet (4) is provided inside the outer rotor (1); The inner and outer surfaces of the stator (3) are evenly slotted, and a set of three-phase symmetrical windings are respectively embedded in the inner and outer surface slots of the stator (3). The windings in the inner and outer stator slots are connected in series or parallel to form The total stator winding of the motor; The entire rotor position is obtained by estimating the position of the magnetic barrier reluctance rotor structure (6), thereby achieving position sensorless control; the detected three-phase current value of the stator is input to the rotor position estimation module (15) to obtain the rotor position. The estimated value and the estimated speed value are obtained by subtracting the estimated value of the rotor position from the given value of the rotor position to obtain the rotor position error value. Input the rotor position error value into the position regulator (8) to obtain the given value of the speed, which is given by Subtract the estimated speed value from the speed given value to obtain the speed error value. Input the speed error value to the speed regulator (9) to obtain the torque given value. At the same time, input the detected three-phase current value of the stator into the stator current. The space vector calculation module (16) obtains the amplitude and space electrical angle of the stator current space vector, and calculates the actual output torque of the motor through the torque calculation module (17). The actual output torque is subtracted from the torque given value, Obtain the motor torque error value, input the motor torque error value to the torque regulator (10), obtain the stator current space vector given value, and input the stator current space vector given value and the three-phase current initial phase into the three-phase The current given value calculation module (11) is used to obtain the given value of the three-phase stator current. Finally, the three-phase stator current detection value is subtracted from the three-phase stator current given value to obtain the three-phase stator current error value. The stator current error value is input to the current regulator (12) to obtain the control signal of the current-controlled PWM inverter (13) to control the synchronous motor.