Research On SiC-inverter Based High Speed Permanent Magnet Synchronous Motor Drive System

The high-speed permanent magnet synchronous motor has high power density,fast dynamic response and wide speed range,which makes it have a broad application prospect.However,due to the small stator inductance of HSPMSM,the current harmonic content is high,and the motor generates severe heat.Reducing the control period and increasing the PWM switching frequency can effectively suppress current harmonics.Therefore,this paper studies the new SiC MOSFET device and its driver circuit and applies it to the HSPMSM drive system to improve the switching frequency and improve the motor control performance.By establishing the SiC MOSFET device model and the equivalent model of the driving circuit,the influence of the key parameters of the driving circuit on the switching performance of SiC MOSFET is analyzed.The parameter optimization method for different performance requirements of SiC MOSFET is studied.The terminal voltage oscillation and crosstalk problems existing in the three-phase inverter of SiC MOSFET are suppressed by the drive loop parameter optimization design and Miller clamp circuit,and the experimental verification is carried out.For circuit reliability design,overcurrent protection is implemented on the hardware through an overcurrent protection circuit based on the oversaturation detection principle.For the high switching frequency,the control period becomes shorter,and the DSP is difficult to complete the vector control algorithm.The FPGA is selected as the main control chip to realize the double closed loop control of the HSPMSM speed current.In order to save FPGA resources,the system algorithm is optimized.The design ideas and solutions was given for the problem that the FPGA can’t perform floating-point operations and can’t directly operate trigonometric functions,including CORDIC algorithm,PI controller,SVPWM modulation,position and velocity calculation,etc.,verify the reliability of the algorithm through logic simulation..The FPGA is used as the main control chip to build an experimental platform based on SiC MOSFET inverter HSPMSM drive system to verify the system.The experimental results show that increasing the switching frequency can effectively suppress current harmonics,improve the steady state performance of the motor,reduce the speed fluctuation and torque ripple,extend the current loop bandwidth,and improve the dynamic response capability of the motor.Finally,the smooth running of the motor speed of 15000 rpm at a switching frequency of 50 kHz is achieved.