Resonant Parameter Design of Asymmetrical CLLC-Type DC Transformer with Robust Voltage Gain

In the renewable energy system, the asymmetrical CLLC-type resonant DC transformer (ACLLC-type DCT) has been widely applied due to its high power-density and low-cost control. Whereas, the main circuit parameters are varying with operation power and temperature in practice, especially at the high-frequency condition. Therefore, the circuit parameters must be properly designed to achieve the robust voltage conversion gain (VCG) when adopting the open-loop scheme. To solve the above problems, this paper presents a special parameters design approach for DCT. In the proposed approach, all unknown parameters are replaced with two equivalent variables with the help of the mathematical model simplifications. Subsequently, a two-stage procedure is introduced to complete the parameters design based on the robust VCG requirement. At last, the proposed method is validated in a DCT based prototype.