Control Algorithm Research Of PMSM For Electric Vehicle Based On Environmental Temperature Compensation

Permanent magnet synchronous motor(PMSM)is widely used in electric vehicles(EV)powertrain system because of its significant energy density and power density.However,extreme environment conditions lead to deviations in the primary parameters of motors,such as stator resistance,d-q axis inductance and permanent magnet flux linkage,which seriously affect the accuracy of motor control and the performance of EV.It is of great practical significance to investigate the influence of ambient temperature on the dynamic performance of EV and develop the corresponding temperature compensation control strategy for improving the environmental adaptability of EV.In this paper,PMSM is investigated to improve the control precision of powertrain motors and the dynamic performance of EV.Research and tests on the control strategy based on environmental temperature compensation are implemented.The brief research work are introduced as follows:(1)The vector control model of PMSM is proposed.The concept of coordinate transformation is introduced to decouple and reduce the order of the motor mathematical model,and building the mathematical model in the two-phase rotating coordinate system.According to the principle of unequal inductance between d-q axes of the interior PMSM,a vector control algorithm based on MTPA is proposed.On this basis,the current decoupling compensation model is created to verify the correctness of the vector control model.(2)An on-line parameter identification algorithm for the motor based on model reference adaptive system(MRAS)is proposed.According to the voltage equation in two-phase rotating coordinates,the reference and adjustable model of identification algorithm are constructed.Furthermore,the adaptive rate of parameter online identification is deduced based on Popov's Superstability theory.Simulation model based on the MRAS is established to realize online identification of d-q axis inductance and stator resistance without additional excitation signals.Finally,the validation of the algorithm and the tracking of identification parameters are verified.(3)The control strategy of output torque with temperature compensation based on MTPA is created.The influence of different temperature on the performance of motor material,material parametric variation and output torque are studied.Then the mathematical model between output torque with electromagnetic parameters and ambient temperature is proposed.Based on the control method of MTPA,the output torque at usual temperature which is obtained by the method of torque-current look-up table is demonstrated as estimated torque.The torque error at different temperatures can be compensated by this means.At the same time,the on-line identification results are fed back to the motor model to form a closed-loop control strategy of torque compensation.(4)the RCP experimental verification of the driving motor model and HIL simulation test of the microcontroller are implemented.In the vector control model based on the simulation environment of Matlab/DriveSoft,the PMSM rapid control prototype experimental platform is established to verify the effectiveness of the model,and the robustness of double closed-loop control of speed and current.According to it,the off-line model in the Matlab/Simulink is established including driving motor model and control algorithm.After code generation and compilation,the off-line model is download to the dSPACE simulation platform and Freescale microcontroller separately.The hardware-in-the-loop simulation platform of PMSM is created to complete hardware-in-loop simulation to verify the temperature compensation algorithm proposed.