IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

198 / 2017-11-09 15:55:05

Common Mode Modeling and Reduction of GaN-based Full-bridge Inverters

inverters,common mode,gallium nitride,modeling,full-bridge

Plenary track > Common-mode and EMI management

Although GaN HEMTs show great improvement in characteristics compared with Si MOSFETs, the control circuits suffer from high common-mode (CM) noise caused by the high-speed switching actions. CM current will lead to failures of controllers and driver ICs without adequate reduction. Lots of research have been done on the generation and propagation of the CM current, but mainly focus on a single phase-leg. In this paper, the CM current is analyzed based on a full-bridge inverter and a CM propagation model is proposed, in which both phase-legs and all the signal and power paths are considered. The connection of control ground and power ground will lead to the inequality of the phase-legs, which is also analyzed in this paper. To reduce CM current, CM chokes and power supply with low isolation capacitors is employed and voltage sensing
method with high CM immunity is adopted. A 500W full-bridge inverter is implemented and verifies the effectiveness of the proposed analysis and methods.