Research On Permanent Magnet Synchronous Motor Driver Based On SiC MOSFET

Because of high efficiency,high power density and large speed regulation range,permanent magnet synchronous motors(PMSM)are widely used in modern industrie.Currently,PMSM driver usually uses silicon devices for main circuits,but due to their exceeding physical limitations,the use of wide bandgap semiconductor devices such as silicon carbide(SiC)will be the trend of future.Owing to its’ high breakdown voltage and excellent switching characteristics,SiC MOSFET can replace Si IGBT to improve the efficiency of converters.Normally,PWM converters using silicon devices don’t equip with output filters,while,for SiC MOSFET with ultra-fast switching characteristic,the voltage reflection phenomenon will occur in very short transmission cables,and the overvoltage problem seriously threatens the insulation safety of PMSMs.In view of such problem,this paper chose to install an LC filter on the SiC MOSFET converter outputting,which can filter out the high-frequency switching sub-voltage harmonics of output voltage,and the output voltage waveform would be sinusoidal.However,the existence of the capacitor branch made the current of inverter side and the motor side inconsistent,which negatively affected the vector control effect of the PMSM.In order to achieve the accurate control of the motor side current under the condition of equipping with output LC filtering,this paper made research on the control method of inverter side current feedback(ICF)plus fundamental capacitance current compensation,in which the fundamental component of the capacitor current was extracted based on the second-order generalized integrator(SOGI)capacitor voltage differential algorithm,only the capacitor voltage sampling was indispensable,which saved system costs.For the PMSM vector control system,the output LC structure and the stator inductance of the motor formed the LCL structure,which put forward the stability requirements for the parameter design of the current regulator.In this paper,the requirements of the regulator parameter were given through analyzing the stability of the system,and the conclusions of the analysis were verified by simulation.Finally,the experimental results verified the severity of the overvoltage problem and the effectiveness of the converter control strategy with LC filtering.