Research On Vector Control Strategy Of Open Winding Hybrid Permanent Magnet Material Brushless Motor

Electric vehicles which have the characteristics of energy saving and environmental protection have become new direction of automobile industry gradually.As the critial execution section of electric vehicles,the vehicle drive motor will directly affect the overall performance of electric vehicles.In various types of motors,the permanent magnet brushless(PMBL)motor has been widely applied in electric vehicles due to its high power density,high efficiency and good dynamic response.However,because of the expensive price and excessive exploitation of rare-earth materials which used in PMBL motor widely,the application of less-rare-earth PMBL motors has attracted considerable attention.Being hybrid excited by rare-earth materials and non-rare-earth materials,the less-rare-earth PMBL motor not only can reduce the usage of rare-earth materials,but also can achieve similar performance of rare-earth PMBL motors.This kind of motor which is adopted in this paper is called hybrid permanent magnet material brushless(HPMM-BL)motor.In addition,the voltage of electric drive system is limited by the capacity of battery.There,it could limit the speed range and power density of the motor in Electric vehicles.Combined with the requirements of the Electric vehicles,a novel open-winding topology with common DC bus and control strategy are applied for promoting power density and torque output capacity of the HPMM-BL motor.First of all,in order to improve the DC bus voltage utilization effectively,a decoupled space vector pulse width modulation(SVPWM)strategy in α-β-0 3D frame has been proposed.Compared with the intermediate hexagon SVPWM which does not generate common mode voltage,the voltage output capability of decoupled SVPWM is increased by 15%.Based on the Matlab/Simulink system,the effectiveness of the two algorithms has been proved,it is also analyzed that the DC bus voltage utilization of decoupled SVPWM is higher.Afterwards,as the neutral point of traditional motor is been disconnected of open-winding structure,zero-sequence current will be produced in the winding which can reduce the efficiency and operational stability.For eliminating the 3th and 9th current harmonics caused by common-voltage and zero-sequence components in the back-EMF,a close-loop system based on repetitive controller(RC)in zero-sequence circuit has been put forward.Finally,the accuracy and reliablity of the algorithm have been proved by simulations based on Matlab/Simulink and experiments based on d SPACE DS1007 system.