Research Of PMSM Sensorless Control Based On GaN Inverter

Energy-saving and environment-friendly electric vehicles are the development trend of the world’s automotive industry,which puts forward higher requirements for the permanent magnet synchronous motor drive system for vehicles.It is hoped that it has higher power density,reliability and efficiency,and requires a higher motor position and speed control accuracy.Therefore,in this paper,the wide-bandgap semiconductor material GaN is applied in the field of motor drive to improve the efficiency of the drive system.The open-circuit fault diagnosis of GaN inverter power devices and sensorless control algorithm of permanent magnet synchronous motor are carried out.Fast opencircuit fault location and high precision and high performance sensorless control scheme of GaN power devices are discussed.Solve the safety and reliability of GaN-based servo system.The specific work is as follows:Firstly,the static characteristics and switching characteristics of eGaN FETs are analyzed.The static output characteristics,third-quadrant conduction principle and characteristics of GaN power devices are explored,and compared with Si MOSFETs.The non-ideal switching process considering parasitic parameters is analyzed in detail,and the dual-pulse simulation model was built with LTspice to study the effects of different circuit driving parameters on switching characteristics such as switching speed and energy loss,which provides an effective reference for the actual circuit design.Secondly,in view of the complex driving conditions of vehicles,and the fact that mechanical sensors are susceptible to environmental interference,which leads to large errors in position signals.In order to achieve high-precision control of rotor position and speed of PMSM(Permanent Magnet Synchronous Motor),the principle of vector control of permanent magnet synchronous motors was firstly studied,and a general Luenberger sensorless observer was constructed to replace the mechanical sensor.For the general Luenberger observer,the observer based on constant feedback gain matrix has the problem of difficulty in parameter design and waste of manpower.According to the idea of pole placement,an adaptive feedback gain matrix is constructed,and combined with sliding mode control method.The PMSM Luenberger-sliding mode sensorless observer based on adaptive gain is designed.The simulation results show that it has good dynamic and static performance under the speed step,sudden load,and different parameters of the motor,and the observer has high observation accuracy.Thirdly,aiming at the risk of inverter failure due to the high-frequency switching action and the occasional harsh operating environment of the permanent magnet synchronous motor drive system for vehicles during long-term operation,in order to ensure the reliability of the PMSM control system,the vector control method is combined.Mixed logic dynamic(MLD)model is applied to the PMSM drive system,and a fault diagnosis method based on the current residual of the MLD model is proposed.Using the three-phase current residual information,the rapid diagnosis of any single or double tube faults is realized.This eliminates the need for additional sensors and speeds up fault diagnosis.Finally,by building a hardware experiment platform with TMS320F28069 as the main control chip,the proposed method is verified by using a surface-mounted permanent magnet synchronous motor.