Research On Zero-sequence Current Suppression Strategy Of Open-end Winding Five-phase Permanent Magnet Motor With A Single DC Supply

Open-end winding motors(OEWM)have the advantages of high utilization DC bus voltage,good fault tolerance,and high power density.They have broad application prospects in high-voltage and high-power applications.According to the classification of the power supply of open-end winding motors,it can be divided into common DC bus open-winding motors and isolated DC bus open-winding motors.Compared with isolated DC bus structures,the common DC bus structure has the advantages of low cost and simple structure,but the common bus structure exists zero sequence loop.When there is zero-sequence voltage in the loop,the system will generate zerosequence current and affect the performance of the motor.Therefore,for open-winding motors of common DC bus,the suppression of zero-sequence current is a very important issue.In the past two decades,scholars have conducted research on the suppression of zero-sequence current of open-end winding induction motors,open-end winding permanent magnet synchronous motors(OW-PMSM),and open-end winding fivephase induction motors,but there is no literature on the suppression of zero-sequence current of open-end winding five-phase PMSM.This paper draws on the mathematical model of the five-phase PMSM and derives the mathematical model of the open-end winding five-phase PMSM in the stationary coordinate system and the rotating coordinate system.The zero-sequence path of the open-end winding five-phase PMSM of the common DC bus is analyzed in detail.The influence of permanent magnet harmonics on the zero-sequence current is studied.In order to suppress the zerosequence current of open-end winding five-phase PMSM,this article discusses the following four techniques:1)Investigate the 144° decoupling nearest four vector space vector pulse width modulation(NFV-SVPWM)technology of the five-phase dual inverter.Decouple the dual inverter reference vector into two same amplitude reference vectors 1 and 2 with the 144° phase shift,and as the reference vector of inverter 1 and inverter 2.Analyze the zero-sequence voltage generated by the dual inverter,and select a specific vector combination to make the zero-sequence voltage generated by the dual inverter zero at any time.2)Study the five-phase dual inverter average zero sequence voltage elimination unified voltage modulation(UVM)technology,to calculate the zero sequence voltage generated by the dual inverters in a PWM cycle.By adjusting the action time of the zero vector to make the average zero-sequence voltage zero generated by the dual inverters in one PWM period3)Research based on zero vector reallocation space vector 180° decoupling modulation technology,decouple the dual inverter reference vector into two reference vectors of equal size and opposite directions,and use them as reference vectors of inverter 1 and inverter 2 respectively.By adjusting the action time of zero vector of inverter,the zero-sequence voltage generated by the dual inverter can compensate the harmonic back-EMF of the permanent magnets to suppress the zero-sequence current4)It is studied to add a proportional resonant controller(PR)on the basis of id =0 control.The PR controller is a single zero-sequence current control loop,which can suppress specific harmonics to suppress the zero-sequence current of the system.In the end,a simulation model of open-end winding five-phase PMSM is established in this paper.The modulation technology of dual inverters and the suppression of zero-sequence current of the system are simulated.In order to further verify the correctness of the algorithm,an open-end winding five-phase permanent magnet motor test platform was built and the corresponding experimental verification was carried out.