Serial Hybrid-Clamped Three-Level Half-Bridge LLC Resonant Converter With Wide Input Voltage Range

A high input voltage converter with a wide input voltage range is crucially required in long-distance submarine power system. However, the concise implementation of high input voltage and wide input voltage ranges remains a challenge for existing converter. In this article, a serial hybrid-clamped three-level half-bridge LLC resonant converter is proposed. The proposed converter can withstand high input voltage by connecting two hybrid-clamped three-level half-bridges in series. All the operating states of the converter are analyzed, five modulation modes are presented, four of which are controlled by pulse frequency modulation, and the other is controlled by changing the equivalent phase shift angle. The five modulation modes cover different voltage gain ranges, and can be combined to achieve wide input voltage regulation while maintaining soft switching of switching devices. The experimental prototype with 1 kW power level and 250 V-2 kV input voltage range is built to verify the wide voltage regulation rang soft-switching performance of the proposed converter.