Optimal Synergetic Control of a Three-Phase Two-Stage Ultra-Wide Output Voltage Range EV Battery Charger Employing a Novel Hybrid Quantum Series Resonant DC/DC Converter

A wide output voltage range (200 − 1000V DC ) isolated two-stage three-phase EV charger is proposed. The system employs a boost-type two-level PFC rectifier front-end and the subsequent novel Hybrid Quantum Series Resonant DC/DC Converter (H-QSRC) output stage, which is left either unregulated with constant voltage transfer ratio or is used to emulate a buck or boost behavior. For reducing the H-QSRC voltage transfer ratio discretization, replacing one of the two-level primary side bridge-legs with a three-level T-type arrangement and a microscopic duty cycle operation are considered. The PFC rectifier stage is either operated in conventional boost-mode with two out of three phases switching (2/3 -mode), or in 1/3 -mode. For 1/3 -mode, always the most positive and the most negative input phase are clamped to the positive and negative DC bus, and only the phase with the smallest voltage / current is switching, which minimizes switching losses. Different combinations of the operating modes of the PFC rectifier stage and the H-QSRC stage and the resulting current and voltage stresses on the main power components are analyzed. Furthermore, the best synergetic combination of the operating modes of both stages is identified for the different output voltage regions. Finally, a corresponding control structure, which achieves a smooth transition between all operating regimes is presented, and it is shown, that the extremely wide output voltage range can be covered without overdesign of any of the two converter stages.