Research Of High Performance Resonant Driver For SiC MOSFET

The loss and volume increase of conventional driving at high frequencies limit the increase of switching frequency and improvement of power density of Silicon Carbide(SiC)devices.Resonant driving can reduce the driving loss and improve the power density,which is a more advanced driving scheme in SiC high frequency applications.Three aspects to be improved in resonant driving are studied in this paper.Firstly,a top-down classification system of resonant drivers is constructed based on the resonance characteristics.The resonant drivers are divided into five resonance modes.The rules of dynamic energy distribution and differences of energy utilization ratio of different resonance modes are studied.The driving loss and driving time performances of different modes are compared based on key parameters.The resonant mode selection and optimization design idea are provided from different perspectives.Then,a drive modeling method based on time segmentation is established.According to SiC switching characteristic and gate capacitance characteristic,the driving process is divided into several sub-stages,and driving time and energy loss are solved piecewise.The driving loss,driving time and device switching time are analyzed from the perspective of resonant inductor and driving resistor.A resonant driver prototype is designed to verify the performance improvement of the above three aspects.Finally,a novel driving speed adjustment method is proposed to realize wide range adjustment of driving time.The driving speed is increased by increasing the initial current of the inductor,and is reduced by means of combined resonant driving.The adjusting range of driving speed is analyzed and derived.Another resonant driver prototype is designed for verification.Different driving speeds can be achieved in driving on and off processes.The speed of a specific stage in device switching transition can also be adjusted by this method.