Research On Zero Sequence Current Suppression Strategy Of OW-PMSM With Common DC Bus

Open winding permanent magnetic synchronous machines have the advantages of high power density,high efficiency and high reliability etc,and meet the needs of high voltage and high power operation.They are widely used in electric vehicles,wind power and other areas.The common DC bus type open winding permanent magnetic synchronous machine has the advantages of simple system structure and High voltage due to the use of one power supply.However,this structure generates zero-sequence current and reduces the motor torque performance.Targeting this problem,model predictive control strategies are applied to the control system of open winding permanent magnetic synchronous machine to suppress the zero-sequence current and improve the control performance of the motor.This article theoretically analyzes the topological structure and working state of open winding permanent magnetic synchronous machines,establishes a mathematical model under three-phase stationary coordinate system,two-phase stationary coordinate system and two-phase rotating coordinate system,and analyzes the space voltage vector principle and its spatial distribution of open winding permanent magnetic synchronous machine;explains the causes and characteristics of zerosequence current,add zero-sequence current suppression term to vector control and model predictive control;in order to improve motor drive performance,the weighting factor in the cost function of the model predictive control system is eliminated,the same variable level in the model predictive current control is used to eliminate the weighting factor,the instantaneous power theory is applied to the model predictive torque control to eliminate the weighting factor,and the model predictive control algorithm is used to suppress the zero sequence current and reduce the torque pulsation.The simulation of open winding permanent magnetic synchronous machine control system is built on the MATLAB / Simulink platform,where the direct torque control strategy,vector control strategy,model predictive current control strategy and model predictive torque control strategy are simulated,analyzed and compared to verify that the model predictive control can effectively suppress the zero-sequence current;the model predictive control strategy with and without weighting factors are compared and analyzed to verify that the model predictive control without weighting factors can improve the dynamic performance of motors.Hardware circuit design and software design for the open winding permanent magnetic synchronous machine control system are conducted,the overall diagram of the open winding permanent magnetic synchronous machine control system,the main circuit module,the inverter drive circuit and the detection circuit are established,the main components are selected,Multisim is used to test the effectiveness of hardware circuits,and a function verification experimental platform based on TMS320F28335 is built.The experimental results prove the effectiveness of the system and its control strategy.The research in this paper has promoted the technical development of open winding permanent magnetic synchronous machines.