Investigation Of The Control System And Characteristics Of Dual Mode Doubly Salient Starter Generator With Variable Winding For Vehicles

Starter generator technology is an important direction in automotive electrical system.At present,switched reluctance machine(SRM)has large starting torque and high power density,but it needs complex control circuit or filter circuit when generating electricity.A doubly salient electromagnetic machine(DSEM)has simple voltage regulation and excellent magnetic regulation performance,but it has large excitation current and relatively low efficiency at low speed.Therefore,a dual-mode doubly salient starter/generator(DMDSS/G)is developed in this paper.By analyzing the operation characteristics of DMDSS/G,the basic topological structure of DMDSS/G is developed.Its excitation winding is opposite to the polar separation winding of armature winding and the winding direction of adjacent stator poles.The asymmetrical double switching power converter circuit is also presented.On the basis of explaining the starting,generating and winding switching principles of DMDSS/G,the mathematical model of DMDSS/G is given,and the control strategy under starting mode is analyzed.By analogy with the design method of SRM,the main structural parameters of DMDSS/G are obtained.In order to clarify the relationship between the structure parameters and the performance of DMDSS/G,the air gap permeance of each phase of the motor is deduced.The analytical expressions of the static torque and the induced voltage are obtained by using the simplified equivalent magnetic circuit model.The parameters of DMDSS/G,such as air gap length,rotor pole arc coefficient and stator pole arc coefficient,are parameterized by finite element method.The effects of these parameters on static torque,armature winding induced voltage,transient torque characteristics and load generation characteristics are studied.The multi-objective optimization function of DMDSS/G is established and the optimal parameters are obtained.The influence of the turn number and the connection form of winding on the comprehensive performance is analyzed.The performance under various winding matching schemes are compared.The optimal scheme is obtained.Based on the principle that the electromagnetic torque is equal,the concept of equivalent turns per pole in starting mode of DMDSS/G is put forward.The specific expression is deduced.The optimized motor is simulated by finite element simulation software,and the magnetic circuit distribution and transient performance of the motor in each mode are obtained.Finally,the hardware and software systems of DMDSS/G controller are designed.The experimental platform of DMDSS/G is built.The experimental results and simulation results show that the motor has high output torque and efficiency in starting mode due to the absence of armature reaction and excitation power consumption.In the power generation mode,only the excitation current can be controlled to realize the voltage stabilization control of the machine.