Research On Drive System Of Hybrid Excitation Synchronous Machine For Electric Propulsion In Electric Vehicle Based On Multi-mode Switching

Hybrid excitation synchronous machine(HESM)is a novel machine which combines permanent magnet synchronous machine and field wounded synchronous machine.The goal is to combines the advantages of both the machines above,so HESM can control excitation flux and has high efficiency.It has an important application prospect in the field of electric vehicle drive system.The research of HESM optimal current control problem is the basic problem that the new type of motor system needs to be solved.In this paper,the efficiency optimization of a novel rotor magnetic shunt hybrid excitation synchronous motor drive system is studied.Firstly,the mathematical model of the motor drive system is established.According to the structural characteristics and operating principle of the rotor magnetic shunt HESM,the mathematical model of HESM is established in the stator and rotor coordinate system.The iron loss model of HESM was established by converting the iron loss into the thermal loss of the variable resistance in the equivalent circuit of HESM.According to the functional characteristics of voltage source inverter and four quadrant choppers,their losses are divided into switching losses and conduction losses,so as to realize the modeling of voltage source inverter and four quadrant choppers.In this paper,the HESM optimal current control strategy based on multi-modes-witching is proposed with respect to the constraints of the current and voltage of HESM.Different control strategies are used in different operation modes of the motor.The Lagrange function of driving system loss is established by using the extended Lagrange multiplier(Kuhn-Tucker Conditions).In the operating mode I and mode II region of the motor,considering constraints of the voltage and current of the HESM,the optimal armature current and exciting current of the drive system under different operating modes are given.The fuzzy control strategy based on particle swarm optimization is used to Realize speed improvements by field weakening.The optimized armature current and exciting current can ensure the realization of the energy dissipation of the drive system in the modal III region,so that the efficiency of the drive system can be optimized in the whole speed range of the motor.The traditional PID control is easy to be affected by the integral saturation,which makes the dynamic performance of the system worse.In this paper,a variable structure Anti-Windup PID controller is used to improve the speed and current double closed-loop dynamic control performance of the drive system.The simulationmodel of the drive system is established and the simulation verification of the optimal current control strategy based on multi mode switching is completed.According to the control principle of the drive system,the hardware structure and software system of the HESM drive system are designed and the experimental platform of 20 KW magnetic shunt HESM drive system is constructed.each function of the HESM drive system is tested.HESM start-up performance test shows that the HESM optimal current control strategy based on multi-mode switching does not sacrifice the dynamic performance of the motor in order to minimize the energy consumption of the drive system.The accuracy and reliability of the HESM model and the simulation results are verified by the experiments of copper loss and motor loss.The efficiency test verifies the superior performance of the HESM optimal current control strategy based on multi-mode switching in minimizing the energy consumption of the drive system.