High Power High Step-Up LLC Resonant Converter with Multimode for Aircraft Applications

In modern aircraft, there is a huge demand for high power high step-up DC/DC conversion from 2SV to 270V or even higher, such as Start Power Unit (SPU) and onboard backup power supply systems. Due to high efficiency, high power density, low EMI, and soft-switching capability, LLC resonant topology are widely used. Moreover, the simple control of LLC topology is benefit for control system design and system reliability. However, when it comes to High Power High StepUp (HPHS) applications, original LLC resonant topology will encounter some problems, resulting lower efficiency, lower power density, and poor parameter controllability. This paper first analyzed these problems, and then proposed a ms-LLC resonant topology with multiple working modes, which is suitable for HPHS applications on aircraft. A 3kW2SV/360V prototype of ms-LLC was designed, fabricated and tested. The feasibility of proposed topology is verified.