Research On Series-Parallel Control Technology Of Multiple Power Modules

Power conversion technology is one of the core issues in the field of electrical engineering,the core problem of power conversion technology is the topology of the converter and the corresponding control strategy.On the basis of the original basic converter,lower production cost and higher reliability topology and control method is the research focus of today.Multi-power module input-series and output-parallel(ISOP)combination system has attracted the attention of researchers in recent years as a new type of power structure with excellent performance.This article mainly studies the ISOP combined system of an Isolated Bidirectional full-bridge DC-DC converter(IBDC),including the ISOP topology of the multi-module IBDC and the three-loop phase shift control strategy,it improves the effect of system power sharing and dynamic response characteristics while ensuring the stable operation of the system.Aiming at the problem that the rated value of the single device does not meet the requirements and low efficiency in high-voltage applications,the isolated bidirectional DC-DC converter is used as the basic unit of the ISOP system.Analyze and study the working principle and working process of IBDC under single-phase-shift control(SPS)and extended-phase-shift control(EPS)strategies,and then perform mathematical modeling and analysis based on this.It is proved that the IBDC power regulation under the EPS control strategy is more flexible and the switching device stress is smaller.And use MATLAB simulation to verify,and then obtain the conditions for soft-switching.Researched and analyzed traditional double-loop phase-shift control strategy.Aiming at the problem that the traditional double-loop control strategy has a poor equalization effect when the ISOP parameters are inconsistent,a three-loop control strategy is proposed and an extended phase-shift link is added to the traditional three-loop control strategy,three-loop phase-shift control.Using small signal analysis to design its extended-phase-shift control loop,input voltage equalization loop,output voltage loop and current inner loop,in order to improve the equalization effect and dynamic response characteristics of ISOP system input voltage equalization output current sharing.In view of the above research content,the software and hardware of the ISOP converter are designed.The simulation schematic diagram of ISOP system based on three-loop extended-phase-shift control is built on MATLAB simulation platform.In thefour cases of completely identical parameters,inconsistent input capacitance,inconsistent transformer parameters,and abrupt input voltage,the ISOP system is simulated and verified.The simulation results show that the designed ISOP system with three-loop extended-phase-shift control has excellent input voltage equalization output current sharing effect and good dynamic response characteristics.