A method and system for calibrating zero position of permanent magnet synchronous motor with different rotation speeds

Abstract

The present invention discloses a method and system for calibrating the zero position of a permanent magnet synchronous motor with different rotation speeds, and relates to the technical field of drive motors for new energy electric vehicles. The method includes: S1: pre-positioning the rotor position and determining the initial zero position value of the resolver; S2: controlling the drive motor to a predetermined speed; S3: implementing zero current control through a controller to allow the motor speed to drop freely; S4: adjusting the zero position value of the resolver to keep the target voltage at zero; S5: recording the zero position value of the resolver at different speeds and fitting the curve to complete the calibration. According to the technical solution of the present application, high-precision resolver zero position angle calibration can be achieved without the need for additional bench resources, which reduces the complexity of the calibration process and has high practical value.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy electric vehicle drive motors, and in particular to a method and system for calibrating zero position of a permanent magnet synchronous motor with different rotation speeds. Background Art

[0002] Permanent magnet synchronous motor plays an important role in the drive system of new energy electric vehicles. It has the advantages of small size, high power density and high electromechanical energy conversion efficiency. It is widely used in industry, manufacturing and national defense. The control of permanent magnet synchronous motor mainly depends on the vector control algorithm. The implementation of this control algorithm requires accurate rotor position information of permanent magnet synchronous motor. At present, most of the ways to obtain the rotor position of permanent magnet synchronous motor are based on resolver (resolver for short). As a position sensor, it has the advantages of resistance to harsh environment, vibration resistance, high reliability and high precision and is widely used. In the development and design stage of the motor, it is ideal to ensure that the zero position of the resolver sensor coincides with the A axis of the motor, that is, the resolver zero position is 0. However, due to the processing and installation deviations in the actual production process, the installation positioning of the resolver sensor is inconsistent, which further leads to differences in the deflection angle of the resolver sensor of each motor. At the same time, due to the existence of the current sampling delay problem of the hardware circuit, the higher the motor speed, the greater the deviation of the rotor angle. This part of the deviation also needs to be calibrated and compensated in the resolver zero angle. Based on the above problems, each motor needs to calibrate the resolver sensor zero angle during the offline detection stage. The detection accuracy of the zero position of the motor resolver will directly affect the working performance, efficiency and other indicators of the permanent magnet synchronous motor. Therefore, the development of a simple and efficient permanent magnet synchronous motor resolver zero position calibration method is imminent.

[0003] Most of the existing electric vehicle motor zero position calibration methods have defects in some aspects. The permanent magnet synchronous motor resolver zero position calibration technology based on fixed current control provides a DC voltage to the motor controller to control the U phase current to a certain value, while the V phase and W phase currents are corresponding negative values, so that the motor rotor is at a fixed position, that is, the A axis coincides with the d axis, and the angle read by the resolver is the resolver zero position angle; this method has a large deviation caused by bearing friction and inertia, and can only calibrate the resolver zero position in a static state. The permanent magnet synchronous motor resolver zero position angle calibration method at dynamic speed uses a dynamometer to drive the measured motor to various speeds, and the controller provides a certain d-axis negative current, adjusts the resolver zero position value to ensure that the bench torque is 0, and thus records the resolver zero position angle at each speed; this method has a high calibration accuracy, but requires the use of bench resources, the motor disassembly and assembly is time-consuming, and the operation is complicated. Therefore, based on this problem, the present application proposes a permanent magnet synchronous motor resolver zero position calibration method and system at different speeds. Summary of the invention

[0004] Technical issues

[0005] In order to solve the above problems, the purpose of the present invention is to provide a method and system for calibrating the zero position of a permanent magnet synchronous motor with a resolver at different speeds, which realizes accurate calibration of the zero position of the resolver sensor by precise control and adjustment of the motor at different speeds. The system only requires a high-voltage power supply and does not require other additional equipment or a special place. The zero position calibration has high accuracy and low complexity of the calibration process.

[0006] Technical Solution

[0007] In order to achieve the above-mentioned objectives, the present invention provides a method and system for calibrating the zero position of a permanent magnet synchronous motor with different rotational speeds, which not only solves the problem of excessive error in the traditional calibration process, but also avoids dependence on test bench resources, simplifies and automates the calibration process, and significantly improves the control accuracy and operating efficiency of the motor.

[0008] In a first aspect, the present invention provides a method for calibrating a zero position of a permanent magnet synchronous motor with different rotation speeds, comprising:

[0009] S1: Pre-position the rotor and determine the resolver initial zero position value;

[0010] S2: Control the drive motor to a predetermined speed;

[0011] S3: Implement zero current control through the controller to allow the motor speed to drop freely;

[0012] S4: Keep the target voltage at zero by adjusting the resolver zero position value;

[0013] S5: Record the resolver zero position value at different rotation speeds and fit the curve to complete the calibration.

[0014] Further, in step S1, the pre-positioning of the rotor position is achieved by applying a specific voltage to the A-axis using the motor controller to ensure that the motor rotor is aligned with the A-axis of the resolver sensor to achieve the initial zero position positioning. At this time, the reading of the resolver sensor is the resolver initial zero position value, which serves as the starting reference point of the calibration process.

[0015] Furthermore, in step S1, the voltage applied by the controller to the A-axis is synthesized based on the three-phase voltage vector output by the space pulse width vector modulation algorithm in the stationary coordinate system.

[0016] Further, step S1 is specifically as follows: the controller and the motor are connected in three phases, and the d-axis voltage Set as target value, q-axis voltage Set to 0, the motor rotor position angle is set to 0; a winding voltage pointing to phase A is generated in the motor winding, and the motor rotor position will be aligned to the A axis of the motor three-phase winding. At this time, the motor rotor position angle is the initial 0 angle.

[0017] Furthermore, in step S2, the speed control of the permanent magnet synchronous motor is based on the current loop PI control strategy, and the controller outputs appropriate voltage instructions to drive the motor to a series of preset speed points; it controls the motor to reach the preset speed points by accurately adjusting the current, thereby improving the accuracy and response speed of the motor control; through the automatic adjustment of PI control, the system can more effectively handle external load changes and reduce speed fluctuations, thereby optimizing the performance and stability of the overall system. The current loop PI control strategy is based on the proportional and integral control principles, and can accurately adjust the current of the motor. The proportional control quickly responds to the deviation signal, while the integral control eliminates the steady-state error and ensures that the motor current reaches and tracks the given current setting value.

[0018] Furthermore, in step S2, the rotor position of the motor is fed back in real time by the resolver sensor and obtained by integrating the target speed signal.

[0019] Furthermore, in step S2, the drive motor is controlled to a predetermined speed through the following I / F strategy: current loop PI control is performed through a motor controller to output voltage; the motor rotor position angle is determined by setting a target speed integral; the target voltage is determined based on the output voltage and the position angle based on park inverse transformation; the three-phase voltage duty cycle is determined based on the target voltage based on a spatial pulse width vector modulation algorithm; and the duty cycle is input to the motor through an inverter.

[0020] Further, step S2 is specifically as follows: the d-axis given current is set to 0, the q-axis given current is set to the target value, and the motor rotor position angle is obtained by integrating the set target speed; the voltage output by the current loop PI control , , , The position angle obtained by integrating the above speed is obtained by inverse transformation of park , , and After being input to the motor through the SVPWM module, the motor gradually increases its speed from a stationary state to the set target speed state.

[0021] Furthermore, in step S3, when the motor reaches a preset speed, the controller stops the current output, that is, the d-axis and q-axis current commands are set to zero, and the motor begins to decelerate freely due to the absence of external torque. The resistance encountered is based on the mechanical friction and wind resistance of the motor. This step also simulates the natural deceleration that the motor may encounter in actual operation.

[0022] Furthermore, in step S3, during the free deceleration of the motor, the controller monitors the back electromotive force of the motor, especially the d-axis voltage, to ensure that it remains in a stable state close to zero.

[0023] Further, in step S4, any deviation of the rotor position is compensated by adjusting the zero position value of the resolver sensor until the d-axis voltage Stable near zero indicates that the resolver zero position is precisely aligned with the actual rotor position to achieve zero-point calibration of the voltage during the free deceleration of the motor; it ensures the alignment of the resolver zero position with the actual rotor position by precisely adjusting the zero position value of the resolver sensor to improve the accuracy of the motor zero position calibration; compensation of the zero position deviation enables the motor control system to more accurately control the rotor position, thereby optimizing the dynamic response and control performance of the motor. The precise control of the permanent magnet synchronous motor depends on accurate rotor position information. The output signal of the resolver sensor is a function of the actual position of the rotor. The accuracy of the resolver zero position directly affects the accuracy of the position signal. Accurate measurement of the rotor position is a prerequisite for achieving vector control and optimizing motor performance.

[0024] Further, in step S4, under the condition that the motor rotor position is accurate and the controller implements zero current control, by adjusting the resolver angle value, the voltage is adjusted according to the back electromotive force at a specific voltage. By keeping it near 0, the resolver zero position value at different speeds of the permanent magnet synchronous motor can be determined.

[0025] Furthermore, in step S4, a mathematical fitting method is used to fit the resolver zero position values ​​obtained by adjustment at different rotational speeds, and a theoretical value curve describing the resolver zero position at different rotational speeds is generated based on the fitting data, which reflects the relationship between the resolver zero position and the rotational speed.

[0026] Furthermore, in step S5, the fitted curve is integrated into the motor controller, and the controller determines the corresponding resolver zero position compensation value according to the real-time speed when in working state. This compensation method can ensure that the motor control system can obtain accurate rotor position information under different operating conditions, thereby optimizing the vector control performance of the motor.

[0027] Furthermore, the method is based on a fuzzy control scheme to ensure the smoothness and accuracy of zero-position calibration. It determines the adjustment direction and amplitude of the resolver zero-position value according to the rotational speed and voltage deviation, and outputs the adjustment amount of the resolver zero-position value according to the fuzzy reasoning mechanism; it can handle the uncertainty and nonlinear problems in the calibration process, so that the system can adapt to different operating conditions and environmental changes, thereby improving the adaptability of the calibration process; the fuzzy controller uses fuzzy logic to make detailed adjustments to the resolver zero-position value, which can achieve more accurate zero-position alignment under complex motor operating conditions and reduce calibration errors.

[0028] Furthermore, the method ensures that the motor maintains stable performance at different ambient temperatures based on a temperature compensation scheme. It calculates the effect of temperature on the resolver sensor output based on the relationship between the resolver sensor output and temperature, and adjusts the resolver zero position value based on the calculation result to compensate for the error caused by temperature change. It can adjust the motor control parameters to adapt to ambient temperature changes and ensure that the motor can maintain precise control performance at different temperatures. By monitoring the temperature in real time for compensation, the motor can better adapt to temperature fluctuations and maintain performance consistency at various ambient temperatures.

[0029] In a second aspect, the present invention further provides a system for zero-position calibration of a permanent magnet synchronous motor with different rotational speeds, the system being based on the method described in the first aspect, comprising:

[0030] A permanent magnet synchronous motor equipped with a resolver;

[0031] A controller for driving the motor and calculating the motor rotor position angle;

[0032] High voltage power supply, used to provide high voltage current to the motor and controller.

[0033] In a third aspect, the present invention further provides a computer device, comprising a processor and a memory, wherein the processor is communicatively connected to the memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, and when the processor executes the computer program, the aforementioned method for zero position calibration of a permanent magnet synchronous motor with different rotational speeds is implemented.

[0034] In a fourth aspect, the present invention further provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the aforementioned method for calibrating the zero position of the permanent magnet synchronous motor at different rotation speeds is implemented.

[0035] The present invention applies voltage to the A-axis through a controller to pre-position the rotor and determine the initial zero position value of the resolver, which ensures that the motor has a known reference point at the beginning of the calibration process, providing a benchmark for subsequent calibration;

[0036] By controlling the motor to a predetermined speed through I / F, it realizes a smooth transition from a stationary state to a target working state, providing stable operating conditions for zero-position calibration; by implementing zero current control through the controller to allow the motor speed to drop freely, it simulates the natural operating state of the motor without external force, providing real dynamic conditions for zero-position calibration; by adjusting the resolver zero-position value to keep the target voltage at zero, it compensates for the deviation caused by the motor manufacturing and installation process through real-time adjustment, improving the accuracy of zero-position calibration; according to the resolver zero-position value fitting curve at different speeds, it provides an accurate resolver zero-position compensation model for the motor control system, ensuring the vector control accuracy under various working conditions. This calibration method and system not only solves the problem of excessive error in the traditional calibration process, but also avoids dependence on bench resources, realizes the simplification and automation of the calibration process, and significantly improves the control accuracy and operating efficiency of the motor.

[0037] Beneficial Effects

[0038] By implementing the method and system for zero position calibration of a permanent magnet synchronous motor with different rotation speeds provided by the present invention, the following technical effects are achieved:

[0039] (1) This technical solution is based on the current loop PI control strategy. The controller outputs appropriate voltage instructions to drive the motor to reach a series of preset speed points: it controls the motor to reach the preset speed points by accurately adjusting the current, thereby improving the accuracy and response speed of motor control; through the automatic adjustment of PI control, the system can more effectively handle external load changes and reduce speed fluctuations, thereby optimizing the performance and stability of the overall system; the current loop PI control strategy enables the motor control system to adapt to different working conditions and requirements, and maintain a stable speed output even when the load or parameters change; at the same time, the PI control strategy reduces the energy loss caused by excessive or insufficient current by accurately controlling the current and voltage, thereby improving the energy efficiency of the motor.

[0040] (2) This technical solution compensates for any deviation in the rotor position by adjusting the zero position value of the resolver sensor until the d-axis voltage stabilizes near zero, indicating that the resolver zero position is precisely aligned with the actual rotor position, so as to achieve zero-point calibration of the voltage during the free deceleration of the motor: it ensures the alignment of the resolver zero position with the actual rotor position by precisely adjusting the zero position value of the resolver sensor to improve the accuracy of the motor zero-position calibration; compensation for zero-position deviation enables the motor control system to more accurately control the rotor position, thereby optimizing the dynamic response and control performance of the motor; accurate zero-position calibration reduces the control error caused by position deviation and enhances the reliability and stability of the motor control system; the calibration process is simplified by means of voltage zero-point calibration to reduce the system's dependence on external bench resources, making the calibration process more efficient and convenient.

[0041] (3) This technical solution is based on a fuzzy control scheme to ensure the smoothness and accuracy of the zero-position calibration: the fuzzy control scheme can handle the uncertainty and nonlinear problems in the calibration process, so that the system can adapt to different operating conditions and environmental changes, thereby improving the adaptability of the calibration process; the fuzzy controller uses fuzzy logic to make detailed adjustments to the zero-position value of the resolver, which can achieve more accurate zero-position alignment under complex motor operating conditions and reduce calibration errors; the fuzzy control scheme avoids the control lag or overshoot that may occur in traditional control methods through a continuous adjustment strategy, thereby ensuring the smoothness and stability of the zero-position calibration process.

[0042] (4) This technical solution is based on a temperature compensation solution to ensure that the motor maintains stable performance under different ambient temperatures: the temperature compensation solution can adjust the motor control parameters to adapt to changes in ambient temperature and ensure that the motor can maintain precise control performance at different temperatures; through real-time temperature monitoring and compensation, the motor can better adapt to temperature fluctuations and maintain performance consistency under various ambient temperatures; it reduces the internal stress and material fatigue of the motor caused by temperature changes, which helps to extend the service life of the motor and reduce maintenance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the above-mentioned permanent magnet synchronous motor rotational zero position calibration method and system of the present invention more obvious and easy to understand, the drawings required for use in the specific implementation of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 A schematic diagram showing the steps of the method for calibrating the zero position of the resolver at different motor speeds is shown;

[0045] Figure 2 A schematic diagram of a rotor pre-positioning control system is shown;

[0046] Figure 3 Shows a schematic diagram of the I / F control system;

[0047] Figure 4 A schematic diagram of the system showing zero position conditions of resolvers at different speeds is shown;

[0048] Figure 5 A schematic diagram showing the effect of the fuzzy control scheme is shown;

[0049] Figure 6 A schematic diagram of the zero-position fitting curve of the resolver at different speeds is shown. DETAILED DESCRIPTION

[0050] In order to facilitate understanding of the embodiments of the present invention, the abbreviations and key terms that may be involved in the embodiments of the present invention are first explained or defined. For undefined abbreviations or key terms, they are commonly understood by those skilled in the art.

[0051] A-axis: The output of the resolver, providing component information of the rotor position;

[0052] d-axis: the axis horizontal to the motor rotor magnetic pole;

[0053] q axis: the axis perpendicular to the motor rotor magnetic pole;

[0054] I / F control: a speed sensorless control strategy with open-loop speed and closed-loop current;

[0055] PI control: A proportional-integral control strategy applied to motor current control;

[0056] , : d-axis voltage, q-axis voltage;

[0057] Park inverse transformation: a process of converting a dq coordinate system that rotates synchronously with the rotor magnetic field into a three-phase stationary coordinate system variable;

[0058] , : Voltage component in αβ coordinate system.

[0059] The present invention will be further described below in conjunction with the accompanying drawings.

[0060] The present invention provides a method for calibrating the zero position of a permanent magnet synchronous motor with different rotation speeds, and the steps are shown as follows: Figure 1 As shown, the specific steps include: pre-positioning the rotor and determining the initial zero position value of the resolver; controlling the drive motor to a predetermined speed; implementing zero current control through a controller to allow the motor speed to drop freely; adjusting the zero position value of the resolver to keep the target voltage at zero; and fitting a curve according to the zero position value of the resolver at different speeds.

[0061] The method for zero position calibration of a permanent magnet synchronous motor with different rotation speeds provided by the present invention specifically includes:

[0062] S1, apply a specific voltage through the controller to position the motor rotor to the initial zero position aligned with the A axis of the resolver sensor, providing a reference for the calibration process;

[0063] The voltage output by the controller current loop is as follows: Figure 2 As shown, the voltage output by the controller current loop Set as the target voltage value, voltage Set to 0, and the motor rotor position angle is set to 0, and the voltage is obtained by inverse change of park and , and then output three-phase voltage through space pulse width vector modulation algorithm , and , which passes through the inverter to the motor end. According to the synthetic vector formula of the three-phase voltage in the stationary coordinate system, the effective synthetic voltage vector points to the A-phase winding axis, and the rotor position of the motor will be aligned to the direction of the A-phase winding. The initial zero angle Offset_Init of the resolver is recorded at this time.

[0064] S2, using the current loop PI control strategy, drives the motor to a series of preset dynamic speed points to simulate different working conditions in actual operation;

[0065] I / F control system schematic diagram Figure 3 As shown in the figure, the I / F control strategy is a speed open-loop and current closed-loop control method. It uses the motor controller to perform PI control of the current loop of the d-axis and q-axis. The specific steps are as follows: a current of 0 is given to the d-axis , the current of the q axis is given the target value , and at the same time give the speed signal Integrate to generate an automatically accumulated angle signal ; Because the current value , angle The virtual coordinate system is generated in the same virtual rotating coordinate system. This virtual coordinate system can be understood as the dq coordinate system where the software applies the vector, represented by the superscript v. There is a phase difference between it and the dq coordinate system where the rotor's real position is located. The phase difference is defined as , at this time The complementary angle is the power angle; the feedback current of the current closed-loop control and The voltage output by the current loop PI control is generated by the sampled three-phase circuit after clark change and park change. , The position angle obtained by integrating the above speed is obtained by inverse park transformation , , and Then the three-phase voltage duty cycle is obtained through the space pulse width vector modulation module, and finally input to the motor through the inverter;

[0066] The electromagnetic torque formula related to the power angle is simplified to:

[0067]

[0068] in, represents the electromagnetic torque, Indicates the number of pole pairs of the motor, Represents magnetic flux.

[0069] The change of power angle is positively correlated with the change of torque, that is, when the load torque increases or decreases, the power angle adaptation increases or decreases accordingly; the characteristic of torque power angle adaptation is to increase or decrease the electromagnetic torque to achieve a new balance; through this control method, the motor gradually increases its speed from a stationary state to the set target speed state; this method has a high success rate and is simple and convenient to implement.

[0070] S3. After reaching the preset speed, the controller stops the current output, and the motor decelerates freely without the action of external torque to simulate the deceleration process in actual operation;

[0071] Different speed resolver zero position condition system Figure 4 As shown, the d-axis is given a current of 0 , the q-axis is given by a current of 0 The motor rotor position angle is obtained by decoding the resolver and the resolver initial zero angle recorded in the above steps is compensated. Because the given current is 0, the controller input to the motor does not generate torque, and the motor will freely decelerate under the action of mechanical friction and wind resistance.

[0072] S4. During the free deceleration process, the controller monitors the back electromotive force of the motor, especially the d-axis voltage, and ensures that the d-axis voltage remains close to zero by adjusting the zero position value of the resolver sensor in real time, thereby compensating for the deviation of the rotor position.

[0073] When the motor rotor position is accurate and 0 current control is performed, the voltage is 0, the motor back EMF is concentrated on the voltage If there is a deviation in the motor rotor position, the back EMF will partially rotate to the voltage According to this method, the zero position of the resolver at different speeds can be calibrated;

[0074] like Figure 4 As shown in the figure, the voltage equation of the permanent magnet synchronous motor in the synchronous coordinate system is:

[0075]

[0076] in, represents the motor stator resistance, represents the output of the PI controller on the d-axis, represents the d-axis inductance, represents the electrical angular velocity of the motor rotor, represents the q-axis inductance, represents the output of the PI controller on the p-axis;

[0077] The motor rotor position is accurate and the current is 0 and the current When the voltage is 0, is 0, the motor back EMF is concentrated on the voltage superior, .

[0078] If there is an angle deviation between the calculated motor rotor position and the actual position , according to the vector rotation formula of the synchronous rotating coordinate system:

[0079]

[0080] The back EMF will partially rotate to the voltage superior;

[0081] Therefore, during the free speed reduction process of the motor, the controller implements zero current control and adjusts the resolver angle value to make the voltage Keeping it near 0 can calibrate the resolver zero position value of the permanent magnet synchronous motor at different speeds. Figure 4 As shown, according to the target voltage of 0 And the current loop controls the output voltage in real time To continuously adjust the resolver zero angle; when it deviates from 0 in the positive direction, try to increase the resolver zero value, monitor the current loop output voltage, if the deviation decreases, continue to increase it until the deviation is 0, otherwise reduce the resolver zero value to 0; conversely, when it deviates from 0 in the negative direction, the adjustment method is the opposite of the above. As the motor speed drops freely, this method can be used to record the resolver zero value at different speeds.

[0082] The fuzzy logic optimization of the zero value adjustment includes: constructing a fuzzy control system, defining input variables that affect the zero value adjustment, such as motor speed, Voltage deviation, adjustment times, etc., define the output variable, that is, the adjustment amount of the resolver zero position value, to guide the precise adjustment of the zero position value; fuzzy set and language variable definition, define fuzzy sets for each input and output variable, such as "low", "medium", "high" and other language variables, build corresponding membership functions for each language variable, and realize the conversion from precise value to fuzzy value; fuzzy rule base development, develop fuzzy rule base based on motor operation experience and data analysis, for example: if the "motor speed" is "low" and " Voltage Deviation” is “High”, then “Zero Adjustment” is “Increase”. Voltage deviation" is "low" and "number of adjustments" is "high", then "zero value adjustment amount" is "reduced"; fuzzy reasoning mechanism design, using fuzzy controller, according to the fuzzy value of the input variable, reasoning through the fuzzy rule base, determine the fuzzy value of the output variable, and use the fuzzy reasoning method Mamdani reasoning method to make fuzzy decisions; defuzzification process, the fuzzy output obtained by fuzzy reasoning is converted into an accurate value through the defuzzification method maximum membership method, so as to be used for actual zero value adjustment; control strategy implementation and feedback, the defuzzified zero value adjustment amount is applied to the motor control system, and the resolver zero value is adjusted in real time through the feedback information of the motor, such as The actual value of the voltage is used to continuously adjust the input of the fuzzy controller to form a closed-loop control system; the performance of the zero-position value adjustment after fuzzy control optimization is evaluated through experiments and simulations, including stability, response speed and accuracy. According to the evaluation results, the parameters of the fuzzy controller are adjusted to optimize the membership function and fuzzy rule base. The effect of applying the fuzzy control scheme is as follows: Figure 5 As shown, the error can be reduced by about 2Nm~4Nm.

[0083] S5. Record the resolver zero position value obtained by adjustment at different speeds, and use a mathematical fitting method to generate a curve describing the relationship between the resolver zero position and the speed; integrate the fitted curve into the motor controller, dynamically query and apply the corresponding resolver zero position compensation value according to the real-time speed, and optimize the vector control accuracy of the motor;

[0084] According to the recorded resolver zero position values ​​at different speeds, the curve formula is fitted through tools such as MATLAB or Excel. The zero position fitting curves of resolvers at different speeds are as follows: Figure 6 As shown in the figure, the zero position values ​​corresponding to four speeds are recorded, namely, speeds Spd1, Spd2, Spd3, Spd4, and the corresponding zero position values ​​Offset1, Offset2, Offset3, Offset4. The curve is fitted based on the above data, and the resolver zero position values ​​corresponding to different speeds during actual operation can be obtained, and compensated to the angle calculated by the resolver to ensure the angle accuracy of the permanent magnet synchronous motor vector control, thereby ensuring the efficiency of the system.

[0085] The temperature compensation scheme monitors the ambient temperature changes in real time and automatically adjusts the motor control parameters to eliminate the impact of temperature fluctuations on equipment performance, ensuring that the motor can maintain high accuracy and stability under various temperature conditions;

[0086] The effect of the temperature compensation scheme is shown in Table 1. It has an effect on improving system performance under different temperature environments. The more extreme the temperature environment, the more obvious the compensation effect, and the more significant the improvement effect on system performance:

[0087] Table 1. Summary of the effects of temperature compensation schemes

[0088]

[0089] It uses NTC thermistors to collect temperature data of the motor and its surrounding environment; according to the motor material and design, a mathematical model between temperature and inductance is established. With temperature The relationship can be approximated as:

[0090]

[0091] in, Indicates reference temperature The inductance value under Represents the temperature coefficient.

[0092] Includes a data acquisition system that reads the output of the temperature sensor in real time and converts it into a temperature value.

[0093] Includes a temperature compensation algorithm that adjusts motor control parameters based on real-time temperature data and uses a PID controller to adjust the motor's supply voltage to compensate for the effects of resistance changes:

[0094]

[0095] in, represents the voltage after compensation, Indicates the nominal voltage, It represents the voltage compensation coefficient derived from the temperature coefficient of resistance;

[0096] For example, suppose , , , , , ;

[0097] The value of the inductor at the real temperature is , the result is 10.075mH; the voltage after compensation is , the result is 223.3V; according to the temperature compensation algorithm, when the ambient temperature rises from 25℃ to 40℃, the motor supply voltage needs to be adjusted from 220V to 223.3V to compensate for the impact of resistance change caused by temperature increase.

[0098] The method and system for calibrating the zero position of the permanent magnet synchronous motor with different rotation speeds provided by the present invention pre-positions the rotor of the drive motor, records the initial zero position value of the resolver, and then uses the I / F to control the drive motor to the target speed, and finally controls the target current to drop to 0 to make it free to decelerate. During the free deceleration process of the motor, the d-axis voltage is continuously iteratively adjusted to obtain the zero position of the resolver corresponding to different speeds, and the curve formula is fitted. It improves the accuracy of the resolver zero position calibration while reducing the system's dependence on external device resources, which is convenient and fast.

[0099] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable non-transient storage media containing computer-usable program code.

[0100] The present invention can provide computer program instructions to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce means for implementing the system.

[0101] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions of the system.

[0102] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions of the system.

Claims

1. A method for calibrating the zero position of a permanent magnet synchronous motor with different rotation speeds, characterized in that: include: S1: Pre-position the rotor and determine the resolver initial zero position value; S2: Control the drive motor to a predetermined speed; S3: Implement zero current control through the controller to allow the motor speed to drop freely; S4: By adjusting the resolver zero position value to keep the target voltage at zero, under the condition that the motor rotor position is accurate and the controller implements zero current control, the resolver zero position value at different speeds of the permanent magnet synchronous motor is determined according to the back electromotive force at a specific voltage; S5: Record the resolver zero position value at different rotation speeds and fit the curve to complete the calibration; The method realizes zero-point calibration of voltage during free speed reduction of the motor by adjusting the zero-position value of the resolver; The method is based on a fuzzy control scheme to ensure the smoothness and accuracy of zero-position calibration, which determines the adjustment direction and amplitude of the resolver zero-position value according to the rotation speed and voltage deviation, and outputs the adjustment amount of the resolver zero-position value according to the fuzzy reasoning mechanism; The fuzzy control scheme includes: fuzzy control system construction, defining input variables that affect zero-position value adjustment, defining output variables, i.e., the adjustment amount of the resolver zero-position value; fuzzy set and language variable definition, defining fuzzy sets for each input and output variable, building corresponding membership functions for each language variable, and realizing the conversion from precise value to fuzzy value; fuzzy rule base development, developing fuzzy rule base based on motor operation experience and data analysis; fuzzy reasoning mechanism design, using fuzzy controller, reasoning through fuzzy rule base according to fuzzy value of input variable, determining fuzzy value of output variable, and using fuzzy reasoning method Mamdani reasoning The method is used to make fuzzy decisions; in the defuzzification process, the fuzzy output obtained by fuzzy reasoning is converted into an accurate value through the maximum membership method of the defuzzification method, so as to be used for actual zero-position value adjustment; control strategy implementation and feedback, the defuzzified zero-position value adjustment amount is applied to the motor control system, the resolver zero-position value is adjusted in real time, and the input of the fuzzy controller is continuously adjusted through the feedback information of the motor to form a closed-loop control system; the zero-position value adjustment performance after fuzzy control optimization is evaluated through experiments and simulations, including stability, response speed and accuracy, and the parameters of the fuzzy controller are adjusted according to the evaluation results to optimize the membership function and the fuzzy rule base.

2. The method for calibrating the zero position of a permanent magnet synchronous motor with different rotation speeds according to claim 1 is characterized in that: Step S1 is as follows: the controller and the motor are connected in three phases, and the d-axis voltage Set as target value, q-axis voltage Set to 0, the motor rotor position angle is set to 0; a winding voltage pointing to phase A is generated in the motor winding, and the motor rotor position will be aligned to the A axis of the motor three-phase winding. At this time, the motor rotor position angle is the initial 0 angle.

3. The method for zero position calibration of a permanent magnet synchronous motor with different rotation speeds according to claim 1 or 2, characterized in that: In step S2, the drive motor is controlled to a predetermined speed through the following I / F strategy: the current loop PI control is performed through the motor controller to output the voltage; the motor rotor position angle is determined by setting the target speed integral; the target voltage is determined based on the output voltage and the position angle based on the park inverse transformation; the three-phase voltage duty cycle is determined based on the target voltage based on the space pulse width vector modulation algorithm; and the duty cycle is input to the motor through the inverter.

4. The method for calibrating zero position of a permanent magnet synchronous motor with different rotation speeds according to claim 1 or 2, characterized in that: Step S2 specifically includes: setting the given current of the d-axis to 0, setting the given current of the q-axis to the target value, and obtaining the motor rotor position angle by integrating the set target speed; The voltage output by the current loop PI control , , , The position angle obtained by integrating the above speed is obtained by inverse transformation of park , , and After being input to the motor through the SVPWM module, the motor gradually increases its speed from a stationary state to the set target speed state.

5. The method for zero position calibration of a permanent magnet synchronous motor with different rotation speeds according to claim 1 is characterized in that: The method ensures that the motor maintains stable performance at different ambient temperatures based on a temperature compensation scheme. The method calculates the influence of temperature on the output of the resolver sensor according to the relationship between the output of the resolver sensor and the temperature, and adjusts the resolver zero position value according to the calculation result to compensate for the error caused by temperature change.

6. A computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, characterized in that: When the computer program is executed, the method for zero position calibration of the permanent magnet synchronous motor at different rotation speeds as described in any one of claims 1 to 5 is implemented.

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