A ZVS Phase-Shift Full-Bridge Converter With Input Current Steering to Reduce EMI Noise

Utilizing an L-C-L network including first primary, a clamping capacitor and second primary, a phase-shift full-bridge converter with input current steering is designed and presented. This proposed converter inherits the advantages of the conventional phase-shift full bridge converter, including dv/dt noise attenuation via its zero voltage switching operation. Moreover, the current steering technique is realized with the help of a clamping capacitor implemented as a built-in second voltage source to share part of input current resulting in di/dt noise reduction. As a result, both di/dt and dv/dt noises can be attenuated and then electromagnetic interference (EMI) performance are improved. A conventional phase-shift full-bridge converter and the proposed converters are built for performance verification with an input from 300 to 390 V, switching frequency 100 kHz, and an output of 24 V, 15 A. Experimental result shows that the input current ripple of the proposed converter can be reduced in half to as small as 2.72 A, as opposed to the 5.20 A by the conventional converter, while the maximum EMI noise is successfully improved to 19.85 dB mu V at 300 kHz.