Design of DC/DC Power Supply Based on Dual Loop Fixed Frequency Control Strategy

A Boost-LLC two-stage DC/DC power supply is designed to address the issues of low efficiency, high loss, and poor stability in wide range voltage input of DC/DC power supply devices for electric vehicles. It has the advantages of a Boost converter with a wide voltage regulation range and an LLC resonant converter with high efficiency. Firstly, we propose a main circuit topology for the Boost-LLC cascaded converter, and the working principles of Boost converter and LLC converter are analyzed in detail. Secondly, a dual loop fixed frequency control strategy suitable for the main circuit topology was proposed. Finally, we develop a simulation model in the Matlab/Simulink software to validate the efficacy of the control strategy. The simulation results indicate that the converter can effectively handle a wide range of inputs and maintain stable output voltage.