Reserch Of Multiphase Parallel Synchronous Rectifier Circuit Based On DSP

Synchronous rectification technology is used in the rectifier circuit,using low on-state resistance MOSFET rectifier diodes instead of conventional to reduce the circuit losses, along with the continuous improvement of supply requirements of the new electronic product,synchronous rectifier circuit is widely used in low voltage and high current output environment.However, the conversion and efficiency of a single phase synchronous rectifier circuit efficiency will be reduced along with the increases of output current.In this paper,parallel operation solutions is sdudied of the multiphase synchronous rectifier circuit. In this scenario, the core technology is to achieve the average output current between modules.Based on the premise of analyzing synchronous rectifier circuit topology and existing current sharing technology, the double forward circuit isselected as the basic structure and the original structure has been improved. Maximum current automatic current law is the main method of control strategy. The main parameters of the parallel module circuit was designed,including calculation and selection of the input and output filter capacitor,parameter design of the transformer and design of drive circuit. The DSP is used as a PID controller to control of the entire system. A new control method is designed to ensure the circuit automatically switch woke-mode according to the changed load.The circuit is set to achieve maximum conversion efficiency under different load conditions.The reliability and power density of the circuit is improved.Using Matlab/Simulink to build a three-phase parallel synchronous rectifier circuit simulation platform. Single-phase and three-phase synchronous rectifier circuit parallel circuit was simulated respectively,and the circuit conversion efficiency was measured under different load conditions by changing the circuit load. The simulation results show that the multi-phase synchronous rectifier circuit could save the problem of the limited load capacity of a single-phase circuit, the simulation results also shows that useing multiphase technology can improve the equivalent frequency and reduce the value of the output voltage ripple.