Research On Waveform Compensation Technology Of High Frequency Full Bridge Inverter Based On GaN Transistor

The new wide bandgap semiconductor device gallium nitride transistor has obvious advantages in improving frequency and power density of the converter compared to the conventional silicon device,which makes it having broad application prospects.This thesis focuses on the research of high-frequency and high-reliability drive and studies the techniques of PWM waveform distortion compensation.It has important theoretical significance and engineering value.This thesis carried out the following several aspects of research work.(1)Gallium nitride device has faster switching speeds and lower drive breakdown voltages,which makes it facing more challenges in driver circuit designs compared to the conventional devices.In this thesis,a double pulse test platform is developed to study the hardware requirements of the driver chip,optimize the layout of the drive circuit,analyze the switching process and improve the accuracy of the loss algorithm.Finally the deployment dynamic characteristics and switching loss of the selected device were tested.(2)There is a problem of duty cycle distortion in high-frequency bridge circuits.Traditional feed-forward compensation schemes are difficult to implement at high frequencies.The one cycle control scheme is used to realize the real-time compensation of the duty cycle,and the traditional one cycle control scheme is simulated to analyze the reasons of the compensation failure mode.Then a closed-loop modulator scheme based on one cycle control is proposed.(3)Based on the full-bridge inverter,the one cycle control scheme is verified by the combination of analog control and digital control,and the hardware circuit design method to reduce the delay of the one cycle control loop is given.A prototype of 270 V input and 115VAC/1200 VA output was developed and the feasibility of theoretical analysis and engineering design was verified by simulation and experiments.