Five-arm Inverter Dual Permanent Magnet Motor Without Position Sensor Control

Permanent magnet synchronous motor(PMSM)has the advantages of high power density,simple structure,small size and high reliability.It has been widely used in coal mine industry,electric vehicle,train traction,wind power generation and intelligent robot.With the development of industrial modernization,more and more occasions require dual-motor coordinated control,the five-leg voltage source inverter(FL-VSI)driving double permanent magnet synchronous motor system is a good fault-tolerant control scheme,which has the advantages of low cost,small size and high reliability;Since the five-leg voltage source inverter has a common leg,so in order to avoid system damage caused by inconsistent switching requirements of two motors on common leg when driving dual-motor,some scholars have proposed the traditional modulation strategy.In the traditional modulation strategy,the longest active voltage vector action time of each motor is half of the control period,so the utilization rate of the DC bus voltage of the motor is limited.Due to the use of mechanical position sensor in the dual-motor system driven by the five-leg inverter,the system cost is relatively increased,the system volume is increased,and the system reliability is reduced,It is difficult to meet the requirements in some situations with more complicated working conditions.Therefore,position sensorless control technology has received widespread attention,Traditional low-speed sensorless control technology mostly uses high-frequency voltage injection method,but this method uses filters many times in the process of high-frequency response signal extraction and signal demodulation.The use of filters will decrease system bandwidth and reduce system dynamics.Aiming at the problems of the traditional modulation strategy,this paper proposes a duty cycle modification strategy,under the condition of ensuring the same duty cycle of the common leg,the active voltage vectors of the two motors are first allocated reasonably to improve the maximum active voltage vector effect of the motors,and then evenly distribute the zero voltage vector to achieve the purpose of speed expansion of the two motors.Aiming at the problems of traditional sensorless control method,this paper proposed a sensorless control method for dual interior permanent magnet synchronous motor(IPMSM)driven by the five-leg voltage source inverter.Firstly,based on the traditional modulation strategy,high-frequency square wave voltage injection is performed in the zero-vector half-period,the active vector control period and the high-frequency injection period are separated,thereby avoiding the use of filters during signal extraction and improving the dynamics of the system.And this paper adopts the method of high-frequency square wave voltage injection under the stationary reference frame(SRF).This method has the advantages of short system convergence time,reducing the influence of motor parameter changes on system observations,and reducing the current distortion of the common leg.Finally,on the basis of theoretical analysis,a simulation model of a dual permanent magnet synchronous motor driven by a five-leg inverter is built using MATLAB/Simulink software,and the experimental verification is carried out on a dual permanent magnet synchronous motor experimental platform with DSP(TMS320F28377D)as the control core,Simulation and experimental results verify the correctness and effectiveness of the duty cycle modification modulation strategy and the position sensorless control method proposed in this paper.