Permanent magnet synchronous motor on-line temperature compensation MTPV control method considering stator resistance

Abstract

The invention relates to a permanent magnet synchronous motor online temperature compensation MTPV control method considering stator resistance, and belongs to the technical field of permanent magnet synchronous motor control. Aiming at the problems of misalignment of a voltage elliptic model caused by neglect of stator resistance in the existing field weakening control and reduction of control precision due to parameter offset caused by temperature rise, the invention provides the following scheme: constructing a voltage elliptic equation considering the stator resistance, and establishing a temperature change model of the stator resistance, inductance and permanent magnet flux linkage; and solving MTPV current tracks at different temperatures in an off-line manner by adopting a Newton downhill iteration method, and dynamically correcting a current instruction through on-line temperature compensation. According to the method, resistance drop compensation and a parameter temperature change self-adaptive mechanism are fused, the problems of voltage ellipse offset and trajectory planning distortion under high-speed and large-load conditions are solved, the high-temperature demagnetization risk of the permanent magnet is suppressed, high-precision torque control over the quadruple speed or above in a wide temperature range is achieved, the current instruction error is reduced by 60% or above, and the torque control precision is improved. And the stability and the speed regulation performance of the motor system of the electric vehicle are obviously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet synchronous motor control, and relates to an online temperature compensation MTPV control method for a permanent magnet synchronous motor taking into account stator resistance. Background Art

[0002] In recent years, the automotive industry's performance requirements for permanent magnet synchronous motors (PMSMs) have continued to evolve toward higher power density and wider speed range. As peak motor power density continues to surpass new heights, the internal thermal load in the system is exponentially increasing, leading to increasingly significant impacts of motor temperature rise on electromagnetic performance, mechanical strength, and operational stability. Research has shown that when rotor temperatures exceed 180°C, the risk of irreversible demagnetization of the permanent magnets increases significantly. This temperature increase also alters key electromagnetic parameters and operating characteristics, impacting motor control accuracy. Torque accuracy is particularly pronounced at high speeds.

[0003] The speed increase of permanent magnet synchronous motors at high speeds is mainly achieved through weak magnetic field control. Existing methods are divided into feedback and feedforward methods. The feedforward method is implemented through offline calibration or current trajectory planning. Its dynamic response performance is good, but the calibration cycle is long and resource consumption is high. The feedback method solves the current trajectory online based on the motor voltage and current equations. Although it can improve the operating point accuracy, it requires high on-board computing power and lacks real-time performance. Existing studies generally ignore the influence of stator resistance when solving the current trajectory. However, as the power density of the motor increases, the skin effect of the stator winding is significant under high-speed and high-torque conditions, and the AC resistance increases significantly. Ignoring the stator resistance voltage drop will cause the voltage-speed ellipse model to be distorted, thereby reducing the current distribution accuracy in the weak magnetic field range.

[0004] Furthermore, key parameters such as stator resistance, inductance, and permanent magnet flux undergo nonlinear variations with temperature during motor temperature rise. Conventional control methods fail to fully incorporate the effects of temperature on these parameters, resulting in an offset in the maximum torque-voltage-to-MTPV current trajectory under high-temperature conditions, making precise control impossible. Existing technologies lack both systematic modeling of the effects of stator resistance and adaptive compensation mechanisms for temperature-dependent parameters, making it difficult to meet the stability and accuracy requirements of high-power-density permanent magnet synchronous motors over a wide speed range. Therefore, there is an urgent need to establish a voltage-speed ellipse model that accounts for stator resistance and integrates an online temperature compensation strategy to achieve precise MTPV control under high-speed temperature rise conditions. Summary of the Invention

[0005] In light of this, the present invention aims to provide an online temperature-compensated MTPV control method for a permanent magnet synchronous motor (PMSM) that accounts for stator resistance. First, a voltage-speed elliptic equation incorporating stator resistance information is established, and the nonlinear system of PMSM voltage and current equations is solved offline using the Newton Downhill Iteration method. Second, online temperature compensation is introduced to characterize the MTPV current trajectory during temperature rise, enabling precise MTPV control of the PMSM under high-speed temperature rise conditions.

[0006] The present invention analyzes the limitations of the traditional PMSM mathematical model and current trajectory that ignores the stator resistance of the motor, and establishes a voltage-speed ellipse equation that takes the stator resistance into consideration. Based on this equation, the influence of the motor temperature-rise voltage-speed ellipse and the MTPV current trajectory at high speed are analyzed from three aspects: stator resistance, dq-axis inductance, and permanent magnet flux. The MTPV current trajectory at different temperatures is solved based on the Newton downhill method, and precise control of the MTPV under high-speed temperature-rise conditions of the motor is achieved through online temperature feedforward compensation.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A method for controlling a permanent magnet synchronous motor (PMSM) with online temperature compensation (MTPV) taking into account stator resistance includes the following steps:

[0009] S1: Establish a voltage limiting ellipse equation for a permanent magnet synchronous motor including stator resistance. The voltage limiting ellipse equation includes stator resistance R s , dq axis inductance L d and L q 、Permanent magnet flux ψ f and electrical angular velocity ω e parameter;

[0010] S2: Analyze the effect of temperature change on stator resistance R s , dq axis inductance L d and L q 、Permanent magnet flux ψ f The influence relationship of temperature change parameters is established;

[0011] S3: The maximum torque-to-voltage ratio MTPV current trajectory at different temperatures is solved offline based on the Newton downhill iteration method to obtain the reference current trajectory at the reference temperature and the compensation current trajectory at high temperature.

[0012] S4: Real-time acquisition of motor operating temperature, interpolation compensation between the reference current trajectory and the compensation current trajectory according to the current temperature, and generation of real-time current command;

[0013] S5: Control the permanent magnet synchronous motor according to the real-time current command.

[0014] Furthermore, in S1, the voltage limiting ellipse equation is:

[0015]

[0016] Among them, i d 、i q are dq axis current, U dc is the DC bus voltage.

[0017] Furthermore, in S2, the parameter temperature change model includes:

[0018] The temperature change relationship of stator resistance Rs is: in is the resistance value at the reference temperature T0, K Cu is the temperature coefficient of copper conductor;

[0019] Permanent magnet flux ψ f The temperature change relationship is where α Br is the temperature coefficient of the permanent magnet remanent flux density;

[0020] dq axis inductance L d 、L q The temperature change relationship is simulated by finite element method to establish a nonlinear mapping table of temperature and current.

[0021] Furthermore, in S3, the Newton downhill iteration method specifically includes:

[0022] Construct a system of nonlinear equations including voltage constraint equations and power extreme value conditions;

[0023] Introducing step size factor λ k ∈(0,1] for iterative step size correction;

[0024] The iterative convergence is controlled by the residual norm monotone descent criterion, satisfying (x k+1 -x k ) 2 +(y k+1 -y k ) 2 <ε 2 The iteration is terminated when .

[0025] Furthermore, the nonlinear equations include:

[0026]

[0027] Furthermore, in S4, the interpolation compensation adopts the linear interpolation formula:

[0028]

[0029] Where T0 and T1 are the reference temperature and high temperature respectively, T now The real-time temperature.

[0030] Furthermore, in S2, the temperature variation model of the dq-axis inductance takes into account the magnetic saturation effect, and the corresponding relationship between the inductance value and the temperature and current value is established through a three-dimensional MAP diagram.

[0031] Furthermore, the S5 specifically includes:

[0032] Input the real-time current command into the current loop controller;

[0033] Generate drive signal by space vector pulse width modulation;

[0034] The drive inverter controls the operation of the permanent magnet synchronous motor.

[0035] Furthermore, in S3, the reference temperature is set to 25°C and the high temperature is set to 145°C.

[0036] Furthermore, in S4, the motor operating temperature is collected in real time by a temperature sensor embedded in the stator winding.

[0037] The beneficial effects of the present invention are:

[0038] (1) By establishing a voltage constraint ellipse equation that takes into account the stator resistance, the ellipse offset problem caused by ignoring the resistance voltage drop in the traditional model is effectively corrected, making the geometric representation of the voltage constraint equation closer to the actual working conditions, thereby optimizing the current trajectory planning in the weak magnetic range and improving the torque output accuracy.

[0039] (2) Combining the temperature variation model of stator resistance, inductance and permanent magnet flux, the voltage ellipse parameters are dynamically corrected to solve the current trajectory offset problem caused by changes in material properties under high temperature conditions, so that the MTPV control strategy maintains stability in a wide temperature range and reduces torque fluctuations.

[0040] (3) The Newton downhill iteration method is used to solve the MTPV current trajectory. Through the step size factor adjustment and residual norm monitoring mechanism, the convergence domain is effectively expanded and divergence is avoided. While ensuring the calculation accuracy, the number of iterations is reduced to meet the real-time requirements of the vehicle controller.

[0041] (4) By coupling the permanent magnet flux temperature attenuation model, the demagnetization current threshold limit is corrected in real time to avoid irreversible demagnetization caused by excessive d-axis negative current at high temperature, thereby extending the service life of the motor.

[0042] (5) The current command is dynamically adjusted through the online temperature compensation mechanism, so that the motor can still run along the optimized MTPV trajectory under high-speed temperature rise conditions, achieving stable torque output within a speed range of 4 times above the base speed, meeting the wide-range speed regulation requirements of electric vehicles.

[0043] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0045] Figure 1 A flow chart of a permanent magnet synchronous motor MTPV control method based on online temperature compensation provided by one embodiment of the present invention;

[0046] Figure 2 A schematic diagram of a conventional current operation trajectory of a permanent magnet synchronous motor provided by one embodiment of the present invention;

[0047] Figure 3 A comparison diagram of the voltage-speed ellipse with and without stator resistance taken into account, provided by one embodiment of the present invention;

[0048] Figure 4 A MAP diagram for reflecting the nonlinear relationship of inductor current at different temperatures provided by one embodiment of the present invention;

[0049] Figure 5 A high-temperature demagnetization curve diagram of a permanent magnet provided by one embodiment of the present invention;

[0050] Figure 6 An embodiment of the present invention provides a process for solving the MTPV current trajectory based on the Newton method. DETAILED DESCRIPTION

[0051] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0052] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0053] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0054] The traditional permanent magnet synchronous motor MTPV current operation trajectory does not take into account the influence of stator resistance. After the stator resistance is introduced, the voltage-speed ellipse will shift toward the third quadrant, resulting in improper selection of the current operating point, such as Figure 3 As shown in the figure, a voltage-speed elliptic equation, taking into account the stator resistance, is established to plan the MTPV current trajectory. This equation comprehensively considers the nonlinear temperature-dependent characteristics of resistance, the nonlinear current-temperature-dependent characteristics of inductance, and the high-temperature reversible demagnetization of permanent magnets. The MTPV current trajectory at different temperatures is then solved using the Newton method. By incorporating online temperature compensation after the speed loop and before the current loop, precise control of the permanent magnet synchronous motor is achieved under high-speed temperature-rise conditions.

[0055] The specific working process of the present invention is as follows:

[0056] 1. Study on the voltage limiting elliptic equation and its temperature variation law considering stator resistance information

[0057] ① Voltage limiting equation taking into account stator resistance information

[0058] The dynamic characteristics of a permanent magnet synchronous motor (PMSM) in a synchronous rotating coordinate system (dq coordinate system) can be described by its voltage equation and torque equation. The voltage equation can be expressed as:

[0059]

[0060] Where u d ,u q and i d ,i d are dq axis voltage and current respectively, Ld , L q is the dq axis inductance, R s is the stator resistance, ωe=npπn / 30 is the rotor electrical angular velocity (np is the number of magnetic pole pairs, n is the mechanical speed), Ψ f is the permanent magnet flux, and p is the differential operator. The electromagnetic torque equation is:

[0061] T e =1.5n p [ψ f i q +(L d -L q )i d i q ] (2)

[0062] From the above formula, we can get the constant torque curve, such as M U(x) (x=1,2,…,max,x is related to torque) as shown in T(max) The maximum torque that the corresponding pmsm can provide under rated working conditions.

[0063] The operation of the PMSM system must meet two types of constraints. The first is the current constraint:

[0064] i d 2 +i q 2 ≤i max 2 (3)

[0065] The maximum allowable current amplitude of the inverter i max Limited, such as M I In addition, excessive negative d-axis current can cause permanent demagnetization of the permanent magnet. d The demagnetization current limit must be met:

[0066]

[0067] Where i dL is the d-axis limiting current, ξ L It is the limit value of the demagnetization coefficient and is determined by the motor parameters.

[0068] The second is voltage constraint:

[0069]

[0070] Characterizes that the motor terminal voltage is limited by the DC bus voltage U dc and electrical angular velocity ω e It is worth noting that the traditional voltage constraint equation ignores the stator resistance R sIts geometrical expression is a family of ellipses in the current plane that shrink as the speed increases, such as Figure 1 Medium M U(x) (x=1,2,…,max,x is related to the speed) as shown, M U(max) Corresponding maximum speed n max The voltage limit circle below.

[0071] In addition, M A is the MTPA trajectory, which will not be discussed in this article; M V The MTPV trajectory, the current operating point follows this trajectory to output the same torque when the motor terminal voltage is minimum, which is the key to achieve the limit torque output in the deep weak magnetic region. U(x) and M T(x) The line connecting the points of tangency.

[0072] Based on the above equation, the current operating area of the traditional PMSM is represented by M A Track, M I Trajectory and M V The trajectory is defined together. When the motor runs at the base speed n A When the maximum torque current ratio trajectory (MTPA trajectory) dominates the current distribution, the operating point is along M A The movement of the trajectory, Figure 1 As the speed increases, the voltage constraint ellipse begins to shrink. When the motor speed reaches the base speed n A When M A 、M I and M U(x) The tracks intersect at point A. After that, the motor enters the field weakening speed expansion stage, which can be divided into field weakening zone I and zone II. A <n≤n V ), the current operating point is forced to move along the intersection of the current constraint circle and the voltage ellipse, that is, Figure 1 In the AV section, the magnetic field is weakened by increasing the negative current of the d-axis to maintain the torque output. When the speed reaches the magnetic weakening boundary speed n V When the intersection of the voltage ellipse and the current constraint circle is the MTPV trajectory (M V The track) overlaps, and the system enters the weak magnetic II area (n>n V In this region, the operating point moves along the line connecting the tangent points of the voltage ellipse and the torque trajectory (i.e., the MTPV trajectory), i.e. Figure 1 VC segment in.

[0073] Figure 2 A schematic diagram of the conventional current operation trajectory of a permanent magnet synchronous motor provided by one embodiment of the present invention.

[0074] The voltage constraint equation (5) is based on the PMSM mathematical model and ignores the stator resistance. However, as the power density of permanent magnet synchronous motors continues to increase, the skin effect of the stator winding becomes significant. Traditional current trajectory planning that ignores the stator resistance will cause the voltage-speed ellipse to deviate and the current operating point to be improperly selected. In this context, it is very necessary to establish a voltage ellipse equation that takes into account the stator resistance.

[0075] Combining equations (1) and (5), the voltage constraint condition taking into account the influence of stator resistance can be modified into equation (6), and its modified trajectory will form a series of inclined ellipses M that change with the speed. U ',like Figure 3 shown.

[0076]

[0077] Figure 3 The medium tilted ellipse consists of 4 elements, the center of the ellipse (x RS ,y RS ), tilt angle θ RS , consisting of the semi-major axis a and the semi-minor axis b. The general equation of an ellipse is defined as in Equation (7).

[0078]

[0079] Combining equations (6) and (7), we can get the coefficients as shown in equation (8).

[0080]

[0081] By combining equations (6) and (8), we can obtain the parameters of the ellipse center, major and minor axes, etc., as shown in equation (9).

[0082]

[0083] ②The impact of temperature change on voltage limit circle

[0084] In the voltage limit ellipse equation considering the stator resistance, including L d 、L q , ψ f With R s Temperature-dependent parameters such as the motor temperature are coupled to the motor temperature. During actual motor operation, temperature exerts a nonlinear coupled relationship on the stator resistance, permanent magnet flux, and magnetic saturation, which affects the voltage limit ellipse and TPV trajectory planning. To ensure the accuracy of the MTPV curve, the impact of temperature changes on these motor parameters should be further explored based on the voltage limit equation that takes stator resistance into account.

[0085] The temperature rise effect caused by the core iron loss and stator copper loss significantly affects its electromagnetic characteristics. sAs a temperature-sensitive parameter, its resistance changes in a positive correlation with the increase of stator temperature, which can be expressed by formula (10).

[0086]

[0087] Where: is the stator resistance value at the reference temperature (such as 25°C); K Cu is the temperature correction coefficient of the copper conductor, which is 0.00393; ΔT is the difference between the operating temperature and the reference temperature.

[0088] At the same time, considering that the magnetic saturation effect of permanent magnet materials will cause the stator inductance to show nonlinear changes with current and temperature rise, based on FEM finite element simulation, the mapping relationship between dq axis inductance and current and temperature is visualized, and the following is obtained: Figure 4 L shown d , L q About temperature and i d ,i q MAP and its rate of change.

[0089] In addition, the rotor permanent magnet is the key component of the permanent magnet synchronous motor and is the main reason for the high torque density. However, the performance of the permanent magnet material depends largely on its operating temperature. The relationship between the magnetic flux density of the permanent magnet and the temperature is as follows: Figure 5 As shown. Permanent magnet flux ψ f The relationship with temperature is:

[0090]

[0091] Where α Br is the temperature coefficient of the permanent magnet's residual flux density, which can be calculated from the residual flux density as follows:

[0092]

[0093] Wherein, B0 is the permanent magnet magnetic flux density when the ambient temperature of the permanent magnet is T0 (room temperature), B1 is the permanent magnet magnetic flux density when the ambient temperature of the permanent magnet rises from T0 to T1, and B0' is the permanent magnet magnetic flux density when the ambient temperature of the permanent magnet returns from T1 to T0.

[0094] 2. Online temperature compensation MTPV control based on Newton iteration solution

[0095] In the deep field-weakening region of a permanent magnet synchronous motor (PMSM), the physical essence of the maximum torque-to-voltage ratio trajectory (MTPV trajectory) lies in optimizing the d / q axis current distribution to minimize the motor terminal voltage at a certain speed while still delivering maximum torque, under given voltage constraints. This trajectory directly determines the system's ultimate torque output capability, which is equivalent to the optimization objective of maximizing electromagnetic power. Based on this, the mathematical representation of the MTPV optimal current trajectory can be transformed into the following constrained optimization problem:

[0096]

[0097] The above equations show nonlinear characteristics due to the existence of square terms and cross terms, and the analytical solution needs to be approximated by numerical iteration method. d 、i q Two variables, let x = i d , y=i q , analyze the derivation process and establish the dual objective functions f(x,y) and g(x,y), as shown in formula (14):

[0098]

[0099] The Jacobian matrix composed of the partial derivatives of f and g is shown in formula (15):

[0100]

[0101] As a classic nonlinear solution algorithm, the Newton iteration method can be expressed in the following format:

[0102]

[0103] Although the Newton method has the advantage of second-order convergence speed, its iterative convergence is heavily dependent on the choice of initial values. Improper initial values can easily lead to divergence. To address this, the Damped Newton Method can be used to improve it by introducing a step size factor λ. k ∈(0,1] to correct the iteration step. Its iteration format can be expressed as:

[0104]

[0105] λ k The iterative correction formula is as follows:

[0106]

[0107] After each iteration, the downhill factor λ kThe correction ensures that the residual norm decreases monotonically after each iteration, effectively expanding the convergence domain. ε is the norm error, which can be adjusted as shown in Equation (17). If it is too small, the solution time will be longer. Before solving, it is necessary to comprehensively weigh the solution time and accuracy.

[0108] (x k+1 -x k ) 2 +(y k+1 -y k ) 2 <ε 2 (19)

[0109] The above is the basic principle of Newton's downhill iteration method. Analyzing Equation (13), under the premise of a fixed voltage-speed ellipse, maximizing torque output can be converted into maximizing power. Equation (13) can be represented as the problem of finding the extreme value of power under voltage constraints. The extreme value of the objective function under the constraint condition is the same as the extreme value of its Lagrangian function. The Lagrangian function can be constructed and the Lagrangian operator can be eliminated to obtain the value of i. d 、i q The function f is shown in formula (20).

[0110]

[0111] By combining equation (20) with equations (17), (18), and (19), and applying the Newton downhill iteration method to solve equation (20), we can obtain the optimal current operating trajectory of the MTPV. The specific solution process is as follows: Figure 6 shown.

[0112] Starting from the perspective of making real-time corrections to the MTPV current trajectory according to the operating temperature, the interpolation compensation idea in engineering calibration is used, and temperature is added as a new dimension. The motor stator temperature T is collected in real time through the motor stator temperature sensor. now , so as to make temperature interpolation correction for MTPV current operation trajectory, such as Figure 1 shown.

[0113]

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for controlling a permanent magnet synchronous motor (PMSM) with online temperature compensation (MTPV) taking into account stator resistance, characterized by: The following steps are involved: S1: Establish a voltage limiting ellipse equation for a permanent magnet synchronous motor including stator resistance. The voltage limiting ellipse equation includes stator resistance R s , dq axis inductance L d and L q 、Permanent magnet flux ψ f and electrical angular velocity ω e parameter; S2: Analyze the effect of temperature change on stator resistance R s , dq axis inductance L d and L q 、Permanent magnet flux ψ f The influence relationship of temperature change parameters is established; S3: The maximum torque-to-voltage ratio MTPV current trajectory at different temperatures is solved offline based on the Newton downhill iteration method to obtain the reference current trajectory at the reference temperature and the compensation current trajectory at high temperature. S4: Real-time acquisition of motor operating temperature, interpolation compensation between the reference current trajectory and the compensation current trajectory according to the current temperature, and generation of real-time current command; S5: Control the permanent magnet synchronous motor according to the real-time current command.

2. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1 is characterized in that: In S1, the voltage limit ellipse equation is: Among them, i d 、i q are dq axis current, U dc is the DC bus voltage.

3. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 2 is characterized in that: In S2, the parameter temperature change model includes: The temperature change relationship of stator resistance Rs is: in is the resistance value at the reference temperature T0, K Cu is the temperature coefficient of copper conductor; Permanent magnet flux ψ f The temperature change relationship is where α Br is the temperature coefficient of the permanent magnet remanent flux density; dq axis inductance L d 、L q The temperature change relationship is simulated by finite element method to establish a nonlinear mapping table of temperature and current.

4. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1 is characterized in that: In S3, the Newton downhill iteration method specifically includes: Construct a system of nonlinear equations including voltage constraint equations and power extreme value conditions; Introducing step size factor λ k ∈(0,1] for iterative step size correction; The iterative convergence is controlled by the residual norm monotone descent criterion, satisfying (x k+1 -x k ) 2 +(y k+1 -y k ) 2 <ε 2 The iteration is terminated when .

5. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 4 is characterized in that: The nonlinear equations include:

6. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1, characterized in that: In S4, the interpolation compensation adopts the linear interpolation formula: Where T0 and T1 are the reference temperature and high temperature respectively, T now The real-time temperature.

7. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1, characterized in that: In S2, the temperature variation model of the dq-axis inductance takes into account the magnetic saturation effect, and the corresponding relationship between the inductance value and the temperature and current value is established through a three-dimensional MAP diagram.

8. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1, characterized in that: The S5 specifically includes: Input the real-time current command into the current loop controller; Generate drive signal by space vector pulse width modulation; The drive inverter controls the operation of the permanent magnet synchronous motor.

9. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1, characterized in that: In the above-mentioned S3, the reference temperature is set to 25°C and the high temperature is set to 145°C.

10. The method for controlling a permanent magnet synchronous motor with online temperature compensation (MTPV) taking into account stator resistance according to claim 1, characterized in that: In S4, the motor operating temperature is collected in real time by a temperature sensor embedded in the stator winding.

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