Research On Torque And Efficiency Optimal Control Method Of Permanent Magnet Synchronous Motor For Hybrid Electric Vehicle

With the shortage of fossil fuels and the aggravation of environmental pollution and other problems,the proportion of traditional fuel vehicles in the market is getting lower and lower,replaced by the rise of new energy vehicles,but pure electric vehicles have problems such as short cruising range and slow charging.These problem has not been resolved for a long time.As a transitional vehicle,hybrid vehicle takes into account the advantages of fuel vehicle and pure electric vehicle,so it has become a research hotspot.Permanent magnet synchronous motors have become the most widely used motors in hybrid electric vehicles due to their high power,high efficiency and high stability.The traditional permanent magnet synchronous motor control system usually adopts the speed and current double closed-loop vector control.However,due to the uneven distribution of the permanent magnets of the permanent magnet synchronous motor itself and the harmonic characteristics of the vector control system,there is a large torque in the electromagnetic torque.pulsation,which in turn affects vehicle stability and ride comfort.Relying on the development project of the PEU motor controller for hybrid electric vehicles,this paper studies how to reduce the torque ripple of the permanent magnet synchronous motor and balance the torque quality and efficiency of the permanent magnet synchronous motor,and strive to meet the requirements of the motor controller for hybrid vehicles.requirements.The main research contents are as follows:Firstly,the mainstream hybrid system structure of heavy commercial vehicles and the structure and working mode of the dual-motor planetary power-split hybrid system selected in this paper are introduced.Taking a commercial vehicle as the application object,the permanent magnet synchronous motor and Controller performance requirements.The basic structure,mathematical model and coordinate change of permanent magnet synchronous motor are briefly described,the control mode of permanent magnet synchronous motor at different speeds is given,and the vector control model of current speed double closed-loop motor is introduced combined with SVPWM algorithm.Aiming at the problem that the speed range of permanent magnet synchronous motor cannot be fully utilized under MTPA control,the speed regulation mode of permanent magnet synchronous motor in the full speed domain is analyzed,and advanced angle field weakening control is added to the motor vector control system to realize MTPA + field weakening.control mode.The control model is built and simulated under MATLAB/SIMULINK,which proves the superior performance of field weakening control in expanding the motor speed.Secondly,an overmodulation algorithm is added to the SVPWM module of the model in order to improve the bus voltage utilization.Aiming at the problem that the overmodulation algorithm generates torque ripple and affects the efficiency of the permanent magnet synchronous motor,a method to find the optimal modulation ratio is proposed.By analyzing the principle of the dual-mode overmodulation algorithm,the voltage vector diagram of mode one and mode two is drawn.By inferring the calculation formulas of the torque,torque ripple and efficiency of the permanent magnet synchronous motor,quantitatively analyzing the size of each performance index of the motor,a motor performance evaluation function is proposed,and based on this,an overmodulation algorithm for modulation ratio optimization is designed..This overmodulation algorithm is added to the control model,and the effect of the designed overmodulation algorithm is simulated and tested in the model.Finally,based on the motor control algorithm in this paper,the hardware principle and software flow of the designed motor controller are introduced.The control board chip is TMS320F28335 from Texas Instruments,and the hardware circuit of the motor controller includes a power supply module,a communication module,a resolver module,a CPU module and a fault detection module.In terms of software,it mainly includes three parts: main flow,main loop and interrupt.After the software and hardware design is completed,the motor experimental platform is built,and the experimental research is carried out.The harmonic characteristics of the motor,the relationship between torque and efficiency,and the external characteristics of the motor are measured and analyzed.The results show that the researched full-speed domain power expansion strategy and motor torque and efficiency optimization methods are effective and innovative.