Research On Digital Controlled Bidirectional LLC Resonant Converter For New Energy Generation System

In the system of new energy power generation,uninterruptible power supply,aerospace power supply,electric vehicle and DC motor drive,bidirectional DC/DC converter is suitable for applications.Bidirectional DC/DC converter has important research value because it can reduce the volume and weight of the system to a great extent and reduce the cost.In this paper,a bidirectional LLC resonant converter for a new energy power generation system is studied.Digital control technology is used to realize the digital control of the converter.This paper first analyzes the new energy power generation system using the principle of the bidirectional LLC resonant converter,using fundamental approximate analysis method to get the equivalent steady state model of bidirectional LLC resonant converter,the voltage gain obtained,and the resonance parameters are designed.Then using the equivalent circuit model method,the bidirectional LLC resonant converter is modeled with small signal,and the transfer function of the switching frequency output is obtained.The PI controller is designed.The main circuit,power device and control circuit of the bidirectional LLC resonant converter are designed,and the software flow chart of the DSP is given.Finally,simulation analysis,build the 1000 W bidirectional LLC resonant converter,a 400V/48 V experimental prototype,the experimental results were analyzed and verified by theoretical analysis and design method,realizes the bidirectional LLC resonant converter for digital control of new energy power generation system.