Research On High-efficiency Control Of Vehicle Permanent Magnet Synchronous Motor Considering Rotor Asynchronous Loss

The development of new energy vehicles is an opportunity and challenge for China’s automotive industry to address the global greenhouse effect and promote the healthy development of the global green ecology.New energy vehicles have an important component that is inseparable from the drive motor as a basic power source.As one of the drive motors,the Permanent Magnet Synchronous Motor(PMSM)has high efficiency and power density,small rotational oscillation,and fast dynamic response.Therefore,it is widely used as an electrical device to drive new energy vehicles.In addition,the depth of research on a permanent magnet synchronous motor as a drive motor is related to determining the performance of a permanent magnet synchronous motor for vehicles and also an important node in the development of new energy vehicles in China.Therefore,this article focuses on the performance of the entire system efficiency based on its traditional permanent magnet synchronous motor drive:(1)For the built-in PMSM,a dynamic model is established,and FOC control and sliding mode DTC control are used for simulation verification.A mathematical model is established in a-b-c three-phase coordinate system.The model was found to be complicated and difficult to understand,so the principle of coordinate space transformation was introduced.Through Clark transformation and Park transformation,the mathematical model in the static coordinate system is simplified to the d-q axis coordinate system,and the voltage equation,stator current equation,stator flux equation and electromagnetic torque equation of PMSM under the d-q axis are obtained to achieve the purpose of simplification.The single control simplifies the mathematical model of PMSM.Then explained the advantages and disadvantages of the control system;Explain the principle of voltage space vector modulation SVPWM and build its simulation model;Finally,based on the characteristics of PMSM and the design requirements of the electric vehicle control system,and using SVPWM as modulation for PMSM control,a traditional FOC control model and a sliding mode-based DTC control model are designed,and simple simulation experiments are carried out.(2)Then,a PMSM minimum loss control strategy based on the model search method is proposed.A loss model considering stator iron loss is established,a search algorithm-the golden section algorithm is elaborated and analyzed,and the optimal flux linkage search controller is designed.The principle of the realization of the PMSM minimum loss control strategy based on the model search method is described.Finally,the PMSM stator flux linkage value is calculated under the given torque _eT and speed N_r,and the PMSM simulation model is established below and above the base speed of the PMSM respectively to verify the proposed control strategy.According to the simulation results,the efficiency of the PMSM minimum loss control strategy based on the model search method is 88.3%under the same working condition in the steady state,while the traditional_di(28)0 control efficiency is 87.8%,so the proposed control strategy method is better than the traditional_di(28)0 control It has better control performance in steady state.(3)Analyzing the working state of the vehicle motor,taking into account the asynchronous loss of the motor during asynchronous operation,establishing an equivalent circuit model considering the rotor eddy current loss of the motor in asynchronous operation,and deriving its dynamic equation,and proposing a method that considers the rotor eddy current in the asynchronous operation of the motor.PMSM minimum loss control strategy for loss.Solve the motor equations under the synchronous and asynchronous operation of PMSM respectively.When the motor is running synchronously,the loss model is equivalent to the traditional loss model that only considers the iron loss.The optimal flux search controller is used to search for the optimal flux linkage of the PMSM under the current operating conditions and calculate the optimal d-axis current;When the motor is running asynchronously,the value obtained from the synchronous calculation is used as the initial value of the asynchronous calculation to solve the optimal shaft current at a given speed and torque;According to the differential speed,switch between synchronous and asynchronous.The simulation analyzes the PMSM high-efficiency control strategy in a wide speed range below the base speed and above the base speed,and compares and analyzes it with the PMSM minimum loss control strategy based on the model search method.According to the simulation results,the efficiency of the proposed control strategy under the same working condition is 91.2%in dynamic time,and the efficiency of the PMSM minimum loss control strategy based on the model search method is 89.5%,so the PMSM minimum loss control considering the asynchronous loss of the rotor The strategy has better control performance.