Design and Practical Implementation of Bridgeless Boost PFC Rectifier With Zero-Current Switching And Fault-Tolerant Operation

Abstract

In this thesis, a new family of zero-current switching (ZCS) BBR with high power factor using only two active switches is proposed. The proposed BBR is based on a totem-pole BBR (TPBBR) configuration which allows the current to flow from high side to low side and vice versa during resonance. Hence, no auxiliary active switch is needed to provide soft-switching for all semiconductor devices. The soft-switching also reduces the body diode reverse recovery problem hence allows the TPBLB to operate in continuous conduction mode (CCM). Design considerations and parameter values calculations are given. An experimental prototype is developed and tested to verify the converter performance. The proposed FTBBR is based on an H-bridge rectifier configuration. Only two out of the four switches are needed to be working in order to ensure the continuity of the converter operation. A detailed analysis of the FTBBR operation under all open-circuit faults of the switches is presented. In addition, adding resonant networks to the FTBBR is also analysed. The FTBBR is controlled using similar PWM controller as proposed in the new ZCS BBR. An experimental prototype is developed and tested to verify the converter performance. The TPBBR requires a special switching techniques and sequences, where isolated gate driver is the best solution which allows both high and low side switches to be turned on simultaneously during resonance. As a solution to the gate driver, a magnetically isolated gate driver with high immunity to leakage inductance is proposed. The proposed gate driver (PGD) is developed based on a bipolar totem-pole gate driver (non-inverting) located on the secondary side of the coupling transformer. It is able to drive a MOSFET/IGBT from standard CMOS to TTL output and down to LSTTL level. It also achieves large duty cycle ratio and small input to output delay and provides reliable isolation. The PGD is analysed and verified experimentally.