Vector magnetic circuit coordinate transformation and motor analysis model establishment method and control method

Abstract

The present invention discloses a vector magnetic circuit coordinate transformation and a motor analysis model establishment method and a control method. First, a vector magnetic circuit model of a surface-mounted permanent magnet synchronous motor is established, and the arc tangent value of the ratio of equivalent magnetic inductive reactance to magnetic resistance is regarded as the iron loss angle. The iron loss angle is used to consider the influence of eddy current and hysteresis effect that cause iron loss on motor performance and its control, and an R-L coordinate transformation and an R-L coordinate system are proposed based on the vector magnetic circuit; then, a surface-mounted permanent magnet synchronous motor analysis model is established based on the vector magnetic circuit and the R-L coordinate system, including a magnetic flux equation and a voltage equation based on the vector magnetic circuit and the R-L coordinate system, and a position sensorless control method is established based on the proposed analysis model. The method proposed in the present invention can fully consider the influence of eddy current and hysteresis effect that cause iron loss on motor performance and its control, and is simple and convenient, with clear physical meaning, and improves the rotor position identification accuracy of position sensorless control.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, and in particular relates to vector magnetic circuit coordinate transformation and a motor analysis model establishment method and a control method. Background Art

[0002] Surface permanent magnet synchronous motor (SPMSM) has the advantages of simple structure, high power density, wide speed regulation range and high working efficiency, and is widely used in industries, electric vehicles, home appliances and other fields. The performance of surface-mounted permanent magnet synchronous motor is not only affected by the structure of the motor body, but the control algorithm also plays a key role. Vector control is one of the most common control methods for surface-mounted permanent magnet synchronous motor. Vector control requires mechanical sensors to provide position information, but sensors inevitably face problems such as hardware failure, reduced reliability, space occupation and increased cost. In order to solve and overcome these problems, position sensorless control strategy came into being.

[0003] In sensorless control, the motor model plays an important role because the rotor position and speed information are estimated based on the relationship between voltage and current. Therefore, it is crucial to establish a more accurate analysis model of the permanent magnet synchronous motor. Iron loss (caused by eddy current and hysteresis effects) is inevitable when the motor is running. However, most of the research on sensorless control of surface-mounted permanent magnet synchronous motors is carried out without considering the influence of iron loss. Using traditional analysis models that do not consider the influence of iron loss will affect the performance of the sensorless control system of the surface-mounted permanent magnet synchronous motor, especially when the motor is running at medium and high speeds.

[0004] Professor Cheng Ming's team from Southeast University discovered the magnetic induction and magnetic capacitance phenomena in the magnetic circuit, established the vector magnetic circuit theory containing the three elements of magnetic resistance, magnetic induction and magnetic capacitance, and the magneto-electric power law, providing a new method for considering the iron loss of the motor, which is different from the equivalent resistance. The active loss caused by the magnetic induction element corresponds to the eddy current loss in the magnetic circuit, and the active loss caused by the magnetic capacitance element corresponds to the hysteresis loss in the magnetic circuit. By introducing magnetic induction and magnetic capacitance into the permanent magnet synchronous motor model, the influence of the eddy current and hysteresis effect that cause iron loss on the permanent magnet magnetic flux and the stator magnetic flux excited by the armature current can be considered. Based on the vector magnetic circuit theory, a new permanent magnet synchronous motor analysis model and control method can be established. Since the model considers both the magnetic circuit and the circuit, the introduction of iron loss is more reasonable, but its form is also more complicated. In this analysis model, the coupling of the d-axis current and the q-axis magnetic flux and the coupling of the q-axis current and the d-axis magnetic flux are introduced into the magnetic flux equation, and the differential coupling term and the rotating electromotive force component of the d-axis current and the q-axis current are added to the voltage equation. The addition of these coupling terms makes the motor model closer to the actual operating conditions of the motor, but increases the difficulty of designing the motor's position sensorless control system. Summary of the invention

[0005] The purpose of the present invention is to propose a coordinate transformation based on a vector magnetic circuit and a surface mounted permanent magnet synchronous motor analysis model, and also propose a motor control method based on the motor analysis model;

[0006] The coordinate transformation based on vector magnetic circuit and the establishment method of the surface mounted permanent magnet synchronous motor analysis model of the present invention are as follows: the magnetic induction is introduced into the d-axis and q-axis magnetic circuit models of the surface mounted permanent magnet synchronous motor SPMSM. and magnetic capacitance C, construct the d-axis and q-axis vector magnetic circuit models, and convert the equivalent magnetic inductive reactance With magnetic resistance The arc tangent value of the ratio is regarded as the iron loss angle δ of the surface mounted permanent magnet synchronous motor SPMSM; the iron loss angle is used to characterize the influence of eddy current and hysteresis effect causing iron loss on the stator flux and permanent magnet flux;

[0007] propose Coordinate system and Coordinate transformation matrix T δ ', said The coordinate system lags behind the dq coordinate system by an iron loss angle δ, based on the vector magnetic circuit and Coordinate system to establish the surface mounted permanent magnet synchronous motor analysis model, including vector magnetic circuit and Coordinate system flux equation and voltage equation;

[0008] Furthermore, the iron loss angle δ of the surface mounted permanent magnet synchronous motor SPMSM is expressed as:

[0009]

[0010] make

[0011]

[0012] k is the equivalent magnetic induction coefficient;

[0013] Since the magnetic resistance is expressed as

[0014] Then, the iron loss angle of the surface mounted permanent magnet synchronous motor SPMSM is expressed as:

[0015] δ=arctan(ωL s k) (3)

[0016] in, is the magnetic induction in the dq coordinate system, C is the magnetic capacitance in the dq coordinate system, is the equivalent magnetic induction in the dq coordinate system, is the magnetic resistance in the dq coordinate system, L s is the inductance in the dq coordinate system, k is the equivalent magnetic induction coefficient, δ is the iron loss angle, ω is the rotor electrical angular velocity, and N is the number of turns of the armature winding;

[0017] Furthermore, Coordinate transformation matrix T δ ′, expressed as:

[0018]

[0019] Furthermore, the flux equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system is obtained:

[0020]

[0021] Multiply both sides of equation (6) by cosδ, and the flux equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system can also be written as:

[0022]

[0023] The d-axis and q-axis flux Coordinate transformation matrix T δ After transformation, we get Axis and Axis flux linkage;

[0024]

[0025] Based on the vector magnetic circuit and The flux equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is:

[0026]

[0027] Furthermore, The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is as follows:

[0028]

[0029] According to the relationship and equation (8), using the d-axis and q-axis currents to replace Axis and The shaft current Axis and The axis flux is expressed by the d-axis and q-axis currents, and from equation (9) we get:

[0030]

[0031] Due to R s sinδ<<ωL s cosδ, ignoring R in equation (10) s sinδ, according to formula (10), based on the vector magnetic circuit and The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is written as:

[0032]

[0033] in, and for Magnetic flux in the coordinate system, and for The voltage in the coordinate system, and for Current in the coordinate system, L s is the inductance in the dq coordinate system, R s is the resistance in the dq coordinate system, ψ f is the permanent magnet flux, δ is the iron loss angle, ω is the rotor electrical angular velocity, and p is the differential operator.

[0034] Furthermore, the voltage term on the left side of equation (10) is expressed in the dq coordinate system, and the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system is obtained:

[0035]

[0036] By performing Clark inverse transformation on equation (12), the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the α-β coordinate system is obtained:

[0037]

[0038] Among them, i α and i β is the current in the α-β coordinate system, u d and u q is the voltage in the dq coordinate system, and θ is the electrical angle of the rotor position.

[0039] Based on the surface mounted permanent magnet synchronous motor analysis model of the present invention, the present invention also proposes a method based on vector magnetic circuit and A position sensorless control method for a surface mounted permanent magnet synchronous motor in a coordinate system includes the following steps:

[0040] Sample the three-phase current of the motor to obtain the sampled value Will The current sampling value in the α-β coordinate system is obtained through the Clark transformation module and Then and The current sampling value in the dq coordinate system is obtained through the Park transformation module and Rotor speed observation The error with the set value n is obtained by the PI controller to obtain the d-axis and q-axis current set values ​​i d and i q ,Will and with i d and i q The error is input into two PI controllers respectively, and we get Voltage setting value in coordinate system and Through the Park inverse transform module, based on the angle Perform Park's inverse transform and Voltage setting value in coordinate system and Transform to obtain the voltage setting value u in the α-β coordinate system α and u β , use u α and u β The synthesized voltage space vector is input into the voltage space vector modulation module for modulation, and the state coding values ​​of the three half bridges at that moment are output to control the MOS tube switches of the three-phase inverter to control the motor; wherein, is the observed value of the rotor position angle.

[0041] The rotor speed observation value and the rotor position angle observation Output by the rotor position and speed observation module;

[0042] The voltage input to the rotor position and speed observation module is

[0043] The current input to the rotor position and speed observation module is the current sampling value in the α-β coordinate system. and

[0044] Compared with the existing model, the above model has the following technical effects:

[0045] (1) The motor analysis model proposed in the present invention, which uses equivalent magnetic induction parameters to account for the influence of iron loss, can take into account the influence of eddy current and hysteresis effects that cause iron loss on motor performance and control, is closer to the actual operating conditions of the motor, and has higher analysis and control accuracy;

[0046] (2) The vector control based on the present invention corrects the voltage based on the iron loss angle in the Park inverse transformation, thereby enhancing the decoupling degree of the d-axis and q-axis current loops, making the surface-mounted permanent magnet synchronous motor step response faster, the current waveform more stable, and improving the performance of vector control.

[0047] (3) Different from the traditional method of using resistance to equalize iron loss, the motor analysis model proposed by the present invention that uses equivalent magnetic induction parameters to account for the influence of iron loss is obtained by considering the relationship between magnetic circuit and circuit at the same time, making the introduction of iron loss more theoretically based. It is also simpler than the model that uses resistance to account for iron loss, and is similar in form to the traditional surface-mounted permanent magnet synchronous motor analysis model that does not consider the influence of iron loss. The traditional surface-mounted permanent magnet synchronous motor position sensorless control method can be used in the invented analysis model after simple improvement, and a position sensorless control system with higher control accuracy can be designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0049] Figure 1 is a flow chart of the method of the present invention;

[0050] Figure 2 The present invention is established Coordinate system diagram;

[0051] Figure 3 The invention is based on vector magnetic circuit and Block diagram of the position sensorless control method of the coordinate system;

[0052] Figure 4 It is a simulation effect diagram of the control method of the present invention;

[0053] Figure 5 This is a simulation effect diagram of position sensorless control when the rotation speed of the present invention is 1200r / min;

[0054] Figure 6 It is a simulation effect diagram of position sensorless control when the rotation speed of the present invention is 3000r / min. DETAILED DESCRIPTION

[0055] Attached Figure 1-3 The invention is a specific embodiment of the motor analysis model establishment method and control method of the vector magnetic circuit coordinate transformation, and the attached Figure 4-6 The simulation results of the specific embodiments verify the effectiveness of the present invention. The described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The present invention proposes a coordinate transformation based on a vector magnetic circuit and a surface mounted permanent magnet synchronous motor analysis and control method, comprising the following steps:

[0057] Step 1: Establish the d-axis and q-axis vector magnetic circuit models of the surface-mounted permanent magnet synchronous motor, and convert the equivalent magnetic inductance and magnetic resistance The arc tangent value of the ratio is regarded as the iron loss angle, which is used to induce the influence of eddy current and hysteresis effect of iron loss on the stator flux and permanent magnet flux;

[0058] Introducing magnetic induction into the d-axis and q-axis magnetic circuit models of surface-mounted permanent magnet synchronous motors The two vector magnetic circuit parameters of magnetic induction and magnetic capacitance C are used to construct the d-axis and q-axis vector magnetic circuit models. The magnetic induction C and magnetic capacitance C characterize the magnitude of the eddy current and hysteresis effect that cause iron loss; Both the magnetic flux and the magnetic capacitance C lag behind the magnetomotive force or current, so the equivalent magnetic induction parameter can be used Equivalent magnetic induction The combined effect of magnetic capacitance C and iron loss is taken into account; in the d-axis and q-axis vector magnetic circuit models, the angle at which the magnetic flux lags behind the magnetomotive force or current is the iron loss angle δ, which can be expressed as:

[0059]

[0060] make:

[0061]

[0062] k is called the equivalent magnetic induction coefficient, which can be measured experimentally. In the present invention, the change of the equivalent magnetic induction coefficient is not considered, and the equivalent magnetic induction coefficient is considered to be a fixed parameter. Since the magnetic resistance can be expressed as The iron loss angle of the surface-mounted permanent magnet synchronous motor can be expressed as:

[0063] δ=arctan(ωL s k) (3)

[0064] In formula (1-3), is the magnetic induction in the dq coordinate system, C is the magnetic capacitance in the dq coordinate system, is the equivalent magnetic induction in the dq coordinate system, is the magnetic resistance in the dq coordinate system, L s is the inductance in the dq coordinate system, k is the equivalent magnetic induction coefficient, δ is the iron loss angle, ω is the rotor electrical angular velocity, and N is the number of turns of the armature winding.

[0065] Step 2: Propose a Coordinate transformation and Coordinate system, such as Figure 2 As shown, The coordinate system lags behind the dq coordinate system by an iron loss angle, based on the vector magnetic circuit and Coordinate system to establish the surface mounted permanent magnet synchronous motor analysis model, including vector magnetic circuit and Coordinate system flux equation and voltage equation;

[0066] Introducing equivalent magnetic induction parameters into the d-axis and q-axis magnetic circuit equations of surface-mounted permanent magnet synchronous motors Then perform Park transformation to obtain the d-axis and q-axis magnetic circuit equations in the dq coordinate system:

[0067]

[0068] In formula (4), and is the magnetomotive force in the dq coordinate system, Φ d and Φ q is the magnetic flux in the dq coordinate system, i d and i q is the current in the dq coordinate system, is the magnetic resistance in the dq coordinate system, is the equivalent magnetic induction in the dq coordinate system, L s is the inductance in the dq coordinate system, ψ f is the permanent magnet flux, ω is the rotor electrical angular velocity, N is the number of turns of the armature winding, and p is the differential operator;

[0069] When the motor is running stably, it is considered that the d-axis and q-axis magnetic circuits are in a stable state, and further, it can be obtained that:

[0070]

[0071] By combining equations (3) and (5), we can obtain the flux equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system:

[0072]

[0073] Furthermore, multiplying both sides of equation (6) by cosδ, we can obtain:

[0074]

[0075] In formula (7), for The coordinate transformation matrix is ​​a matrix that rotates the dq coordinate system in the direction of lag by the iron loss angle δ, thereby obtaining a new coordinate system, that is, Coordinate system, The coordinate system lags behind the dq coordinate system by an angle of δ;

[0076] In formula (5-7), ψ d and ψ q is the magnetic flux in the dq coordinate system, i d and i q is the current in the dq coordinate system, L s is the inductance in the dq coordinate system, ψ f is the permanent magnet flux, ω is the rotor electrical angular velocity;

[0077] The d-axis and q-axis voltage (magnetic flux) are connected through T δ After transformation, we get Axis and Voltage (flux), further based on vector magnetic circuit and The flux equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is:

[0078]

[0079] The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is:

[0080]

[0081] Furthermore, according to the relationship and equation (8), using the d-axis and q-axis currents to replace Axis and The shaft current Axis and The axis flux is expressed by the d-axis and q-axis currents. From equation (9), we can get:

[0082]

[0083] Due to R s sinδ<<ωLs cosδ, ignoring R in equation (10) s sinδ, according to formula (10), based on the vector magnetic circuit and The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is:

[0084]

[0085] By expressing the voltage term on the left side of equation (10) in the dq coordinate system, the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system can be obtained:

[0086]

[0087] By performing Clark inverse transformation on equation (12), the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the α-β coordinate system can be obtained:

[0088]

[0089] In formula (8-13), and for Magnetic flux in the coordinate system, and for Voltage in the coordinate system, u d and u q is the voltage in the dq coordinate system, u α and u β is the voltage in the α-β coordinate system, i d and i q is the current in the dq coordinate system, i α and i β is the current in the α-β coordinate system, L s is the inductance in the dq coordinate system, R s is the resistance in the dq coordinate system, ψ f is the permanent magnet flux, δ is the iron loss angle, ω is the rotor electrical angular velocity, θ is the rotor position electrical angle, and p is the differential operator.

[0090] Step 3: Create a vector magnetic circuit and Position sensorless control method for surface mounted permanent magnet synchronous motor based on coordinate system.

[0091] According to the above-mentioned vector magnetic circuit and The surface mounted permanent magnet synchronous motor analysis model is established in the coordinate system, and a vector magnetic circuit and The coordinate system position sensorless control method is as follows:

[0092] The collaborative working process of each module is as follows: Figure 3As shown, the three-phase current of the motor is sampled to obtain the sampled value Will The current sampling value in the α-β coordinate system is obtained through the Clark transformation module (abc / αβ) and Then and The current sampling value in the dq coordinate system is obtained through the Park transformation module (αβ / dq) and The error between the rotor speed and the speed setting value is passed through the PI controller (PI) to obtain the d-axis and q-axis current setting values ​​i d and i q ,Will and with i d and i q The error is input into two PI controllers (PI), and we get Voltage setting value in coordinate system and Based on angle The voltage setting value u in the α-β coordinate system is obtained through the Park inverse transformation module (dq / αβ) α and u β , use u α and u β The synthesized voltage space vector is input into the voltage space vector modulation module (SVPWM) for modulation, and the state code values ​​of the three half bridges at that moment are output to control the MOS tube switches of the three-phase inverter to control the motor. The rotor speed and rotor position angle used are provided by the rotor position and speed observation module (SMO);

[0093] The Park inverse transformation module in the present invention is to transform The voltage in the coordinate system is transformed into the voltage in the α-β coordinate system, and the angle input to the Park inverse transformation module is the rotor position angle observation value Subtract the iron loss angle δ, that is

[0094] The rotor position and speed observation module in the present invention is designed according to formula (13), and the voltage information input to the rotor position and speed observation module (SMO) is:

[0095] The surface-mounted permanent magnet synchronous motor is simulated for position sensorless vector control. The motor speed is first adjusted to 1200r / min and the load is 7.7N·m, then the speed is adjusted to 3000r / min, and then the load is reduced by 2N·m. The step response speed and the stability of the current waveform are observed, and the effects of the control method of the present invention and the traditional vector control method are compared; the surface-mounted permanent magnet synchronous motor SPMSM is controlled to identify the rotor position and speed information at 1200r / min and 3000r / min respectively, and the position sensorless control based on the model of the present invention is compared with the traditional position sensorless control, and the errors between the observed rotor position and speed information and the actual values ​​are compared to verify the feasibility and effectiveness of the motor analysis model and control method proposed in the present invention. The parameters of the surface-mounted permanent magnet synchronous motor in the simulation are shown in the following table:

[0096]

[0097] like Figure 4 As shown, use i d =0 control, control i d unchanged, in the process of speed regulation and load reduction, the vector control i d The fluctuation is smaller, which improves the speed and stability of vector control in dealing with step response.

[0098] like Figure 5 and Figure 6 As shown in the figure, the position sensorless control based on the model of the present invention improves the rotor position observation accuracy compared with the traditional position sensorless control. The error is reduced by about 0.2 electrical degrees at 1200r / min and by about 0.7 electrical degrees at 3000r / min. Figure 5 and Figure 6 When the speed is high, the iron loss is also greater, which causes the traditional position sensorless control to produce a large identification error. The position sensorless control based on the model of the present invention has a better effect in improving the error.

[0099] The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for establishing an analysis model of a surface-mounted permanent magnet synchronous motor, characterized in that: Introducing magnetic induction into the d-axis and q-axis magnetic circuit models of surface mounted permanent magnet synchronous motors (SPMSMs) and magnetic capacitance C, construct the d-axis and q-axis vector magnetic circuit models, and convert the equivalent magnetic inductive reactance With magnetic resistance The inverse tangent value of the ratio is regarded as the iron loss angle δ of the surface mounted permanent magnet synchronous motor SPMSM; Equivalent magnetic inductive reactance It is expressed as: Where, ω is the rotor electrical angular velocity; propose Coordinate system and Coordinate transformation matrix T δ '; The coordinate system lags behind the dq coordinate system by an iron loss angle δ; Coordinate transformation matrix T δ ′Transform the dq coordinate system to Coordinate system; Based on vector magnetic circuit and Coordinate system to establish the surface mounted permanent magnet synchronous motor analysis model, including vector magnetic circuit and Coordinate system flux equation and voltage equation.

2. The method for establishing a surface-mounted permanent magnet synchronous motor analysis model according to claim 1, characterized in that: The iron loss angle δ of the surface mounted permanent magnet synchronous motor SPMSM is expressed as: make k is the equivalent magnetic induction coefficient; since the magnetic resistance is expressed as Then, the iron loss angle of the surface mounted permanent magnet synchronous motor SPMSM is expressed as: δ=arctan(ωL s k) (3) in, is the magnetic induction in the dq coordinate system, C is the magnetic capacitance in the dq coordinate system, is the equivalent magnetic induction in the dq coordinate system, is the magnetic resistance in the dq coordinate system, L s is the inductance in the dq coordinate system, k is the equivalent magnetic induction coefficient, δ is the iron loss angle, ω is the rotor electrical angular velocity, and N is the number of turns of the armature winding.

3. The method for establishing a surface-mounted permanent magnet synchronous motor analysis model according to claim 2, characterized in that: Coordinate transformation matrix T δ ′, expressed as:

4. The method for establishing a surface-mounted permanent magnet synchronous motor analysis model according to claim 3 is characterized in that: The magnetic flux equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system is obtained: Multiply both sides of equation (6) by cosδ, and the flux equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system can also be written as: The d-axis and q-axis flux Coordinate transformation matrix T δ After transformation, we get Axis and Axis flux linkage; Based on the vector magnetic circuit and The flux equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is:

5. The method for establishing a surface-mounted permanent magnet synchronous motor analysis model according to claim 4, characterized in that: The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is as follows: According to the relationship and equation (8), using the d-axis and q-axis currents to replace Axis and The shaft current Axis and The axis flux is expressed by the d-axis and q-axis currents, and from equation (9) we get: Due to R s sinδ<<ωL s cosδ, ignoring R in equation (10) s sinδ, according to formula (10), based on the vector magnetic circuit and The voltage equation of the surface-mounted permanent magnet synchronous motor in the coordinate system is written as: in, and for Magnetic flux in the coordinate system, and for The voltage in the coordinate system, and for Current in the coordinate system, L s is the inductance in the dq coordinate system, R s is the resistance in the dq coordinate system, ψ f is the permanent magnet flux, δ is the iron loss angle, ω is the rotor electrical angular velocity, and p is the differential operator.

6. The method for establishing a surface-mounted permanent magnet synchronous motor analysis model according to claim 5, characterized in that: The voltage term on the left side of equation (10) is expressed in the dq coordinate system, and the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the dq coordinate system is obtained: By performing Clark inverse transformation on equation (12), the voltage equation of the surface-mounted permanent magnet synchronous motor based on the vector magnetic circuit in the α-β coordinate system is obtained: Among them, i α and i β is the current in the α-β coordinate system, u d and u q is the voltage in the dq coordinate system, and θ is the electrical angle of the rotor position.

7. A surface mounted permanent magnet synchronous motor control method, characterized in that: The analysis model of the surface-mounted permanent magnet synchronous motor is established based on the establishment method described in claim 6, and the control method comprises the following steps: Sample the three-phase current of the motor to obtain the sampled value Will The current sampling value in the α-β coordinate system is obtained through the Clark transformation module and Then and The current sampling value in the dq coordinate system is obtained through the Park transformation module and Rotor speed observation The error with the set value n is obtained by the PI controller to obtain the d-axis and q-axis current set values ​​i d and i q ,Will and with i d and i q The error is input into two PI controllers respectively, and we get Voltage setting value in coordinate system and Through the Park inverse transform module, based on the angle Perform Park's inverse transform and Voltage setting value in coordinate system and Transform to obtain the voltage setting value u in the α-β coordinate system α and u β , use u α and u β The synthesized voltage space vector is modulated by the input voltage space vector modulation module, and the state coding values ​​of the three half bridges are output to control the MOS tube switches of the three-phase inverter to control the motor; wherein, is the observed value of the rotor position angle.

8. The motor control method according to claim 7, characterized in that: The rotor speed observation value comprises the following steps: and the rotor position angle observation Output by the rotor position and speed observation module; The voltage input to the rotor position and speed observation module is The current input to the rotor position and speed observation module is the current sampling value in the α-β coordinate system. and

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