A single-stage bridgeless high efficiency ZVS hybrid-resonant off-road and neighborhood EV battery charger

This paper introduces a single-stage battery charger for neighborhood electric vehicles (NEVs) which has the following characteristics: i. operate in continuous-conduction-mode (CCM), ii. include bridgeless operation, iii. realize zero-voltage switching (ZVS) operation for all MOSFETs, iv. provide controlled di/dt turn-off of the output diodes, v. has symmetric operation. The proposed battery charger exhibited minimum number of semiconductor devices compare with state-of-the-art battery charger. The input-output isolation reduces the possibility of safety hazards. The proposed isolation transformer acts as an AC transformer which is much smaller in size and increase transformer efficiency. The symmetric operation of the proposed converter reduces the common-mode (CM) noise. In the paper, the operation of the proposed converter is explained in detail and a mathematical analysis of its steady-state operation is performed. The feasibility of the converter is confirmed by comparing an experimental prototype of the benchmark hard switched ac-dc current-fed push-pull converter and simulation work of the proposed converter. Through experimentation and analysis the proposed converter can achieve a total loss reduction of 20 %, at 70 kHz switching frequency, 120 V input, and 48 V/650 W output.