Research On Control Strategy Of In-wheel PM Motor Under Different Operating Conditions

The electric vehicle industry has developed rapidly under the incentives of the market,since the motor drive system has outstanding advantages over the traditional internal combustion engine in terms of cleanliness,operating efficiency and vibration noise.As the latest driving form of electric vehicle,the distributed-driven in-wheel motor has potential application prospect in electric vehicle for its simple structure,high integration,and high transmission efficiency.In recent years,the common DC bus open-winding motor system has been widely concerned by experts and scholars because it can effectively improve the output and widen the speed range of motor system under limit of vehicle battery voltage and capacity.and enhance the fault tolerance ability of system.In this paper,an external rotor type flux switching permanent magnet motor used in distributed hub motor driving electric vehicle is used as the research object,and the open winding driving control system of this kind of motor is constructed.The control strategy under variable working conditions is put forward to realize the wide speed range,low zero sequence current and strong tolerance performance of permanent magnet hub motor.The main contents of the thesis are as follows:1)Firstly,the working principle and topology of the FSPM motor are introduced,and the mathematical model of the FSPM motor based on the open winding topology of the common DC bus is constructed.The causes of the zero-sequence sequence component of the motor system under the open-winding structure,and lays a foundation for the full text research.2)Considering the spatial vector distribution of open-winding topology,the influence of different basic voltage vectors on motor drive system is analyzed.On this basis,the traditional decoupling modulation strategy and the intermediate hexagonal modulation strategy are simulated and analyzed experimentally.3)To meet the complex multi-operating condition requirements of electric vehicles,a modulation strategy called phase-shifting decoupling modulation strategy that can be decoupled at any angle is proposed.By effectively adjusting the angle of shift decoupling,the speed range and zero sequence component of motor drive system are controlled with balance.4)The control strategy of electric vehicle under multiple operating conditions is studied.Electric vehicles’ operating conditions incloud ‘low speed driving’,‘acceleration’ and ‘deceleration’ and ‘high speed cruise’ and others.Furthermore,the maximum torque per current control,integrated sliding mode closed-loop control,agnetic-weakening control are combined with phase-shifting decoupling modulation strategy respectively to realize optimal control of external rotor FSPM motor under corresponding working conditions.5)Finally,the effectiveness of the proposed method is verified by simulations and experiments by MATLAB/Simulink and the experimental platform based on d SPACE DS1007.