Research On Wide Speed Range Operation Strategy Of Indirect Matrix Converter-permanent Magnet Synchronous Motor System

Indirect matrix converter-permanent magnet synchronous motor system has the advantages of high power density,energy feedback and controllable power factor,which is widely concerned by researchers.However,the maximum linear voltage transfer ratio of the indirect matrix converter is only 0.866,which limits the maximum speed of the drive motor system and limits its application and promotion.In this paper,the modulation method of indirect matrix converter and the flux-weakening control strategy of permanent magnet synchronous motor are studied,and and a wide speed range operation control strategy of overmodulation and flux-weakening coordination is proposed.In the aspect of overmodulation,this paper designs overmodulation methods of the rectifier stage and the inverter stage overmodulation synthetically,which can increase the fundamental voltage transfer ratio of indirect matrix converter to 1.In the aspect of flux-weakening control,considering variation of voltage limit boundary of indirect matrix converter with motor speed,flux-weakening control is implemented based on voltage error feedback method,which maximums voltage utilization rate by setting endpoint of output voltage vector on the voltage boundary during flux-weakening operation.In the aspect of system control,the rectifier stage modulation depth controller is designed,which combines the rectifier stage overmodulation and flux-weakening control organically,so the rectifier stage overmodulation is automatically switched on or off according to operation requirements by a modulation depth controller,and further broaden the speed range.The experimental prototype of the indirect matrix converter-permanent magnet synchronous motor system is constructed,and a 4k W surface mounted permanent magnet synchronous motor is used as the experimental object for experimental verification.The experimental results show that,compared with the traditional maximum torque per ampere vector control strategy,the strategy proposed in this paper can effectively improve the transient performance of the motor while increasing the maximum speed by about 35%.