Voltage-Controlled Series Resonant DC-DC Converter for Solid State Transformer Applications

Resonant converters are used in wide range of power electronic converters applications such as solid state transformers (SST). Over a wide range of load, LLC resonant converters allows converter to achieve ZVS/ZCS. The cost of SSTs are reported to be more than five times higher than the traditional transformers partly due to complex control methods used in their designs. This paper proposes an amplitude modulation technique based on resonant current control for voltage regulation. The error in the output voltage is used to regulate the quantum energy in the resonant tank. The converter switching frequency is synchronized with the resonant current to achieve a self-tuned controller. The controller achieves softs witching across the MOSFETs of the primary converter. Its implementation is based on simple and cost effective logic gates which eliminates the need for complex programming of DSPs and FPGAs. The simulation results show the effectiveness of the proposed controller which is validated with experimental results