A Comparison among Wide Bandgap Devices using a CLLLCBidirectional Resonant Converter

Abstract:
In this paper, the design of a 6.6 kW 500 kHz CLLLC bidirectional resonant converter platform is presented, which has been used to compare wide bandgap semiconductors of different technologies: GaN with cascode structure and SiC. The platform, designed by simply changing the gate driver board in it, permits rapidly changing from GaN to SiC and vice versa. The converter is able to operate with an input voltage of 380–600 V, an output voltage of 280-450 V and a maximum power of 6.6 kW, using a frequency operating range of approximately 300-700 kHz, which, along with the resonant behaviour of the converter, allows very high power density and reduction of the passive components. In addition, synchronous rectification is implemented in the secondary, achieving a compact design. Several measurements have been conducted using the same platform to compare the semiconductors from different technologies using commercial discrete devices for several frequencies in different operation modes (below, at, and above resonant frequency). Efficiency, switching times and their waveforms and the influence of gate resistors on the commutation process have been the figures selected to benchmark the semiconductor technologies.