Design Of Permanent Magnet Synchronous Motor Drive System For Electric Vehicles Based On Gallium Nitride

Permanent magnet synchronous motors are widely used in the field of new energy electric vehicles.With the development of intelligent and precise technology in the industrial information age,there are higher requirements for motor driver power density and dynamic response performance.The Si material has reached the material characteristics limit in terms of switching speed and on-state resistance.Compared with traditional Si devices,the new gallium nitride(Ga N)devices have higher switching frequency and switching speed,and smaller on-resistance.And stronger high temperature working ability.Therefore,applying Ga N power transistors to permanent magnet synchronous motor drives is expected to reduce losses,increase efficiency,improve output torque stability,and improve dynamic performance.With the continuous development of Ga N devices and the continuous reduction of costs,the application of Ga N in permanent magnet synchronous motor drives continues to emerge.This article designs a permanent magnet synchronous motor drive system based on Ga N devices.This paper first establishes the dynamic mathematical model of the permanent magnet synchronous motor in the three-phase static coordinate system and the dq rotor coordinate system,and then studies the SVPWM modulation method and its implementation.Detailed analysis of eGaN HEMT output characteristics,transfer characteristics,third-quadrant conduction characteristics for analysis,comparative study of eGaN HEMT and traditional Si MOSFET,IGBT conduction characteristics.Analyze the turn-on and turn-off process of eGaN HEMT based on the synchronous buck converter,and study the mechanism of operating conditions,driving parameters and parasitic parameters that affect the switching characteristics of eGaN HEMT.According to the particularity of the eGaN HEMT drive circuit,considering the drive chip,drive parameters and PCB layout,the eGaN HEMT drive circuit design method is proposed,and the double pulse test(DPT)platform is built to verify the effectiveness of the method.Analyze the influence of switching frequency and dead time on current harmonics and torque ripple based on FFT.Study the effect of high switching frequency on the current loop bandwidth.The current loop control parameters considering the digital delay are designed,and the modulation and control strategy studied in this paper are simulated to verify their correctness and effectiveness.An experimental platform for a 1.5k W e Ga N-based permanent magnet synchronous motor drive system was built to verify the reliability of the designed eGaN HEMT motor drive system and the effectiveness of the control method.