Research On Parallel Combined Converter Based On Dual Active Half Bridge(DAHB) Module

Dual Active Half Bridge converter(DAHB)can realize bidirectional flow of power.It is widely used in new energy storage systems,automotive batteries and DC bus voltage conversion.Increased,its switching devices face the problem of large current stress.This paper mainly researches DAHB,using two DAHB modules in parallel to reduce the high current stress problem of a single module in high power applications,and the current sharing problem between its modules is studied.This paper first analyzes the working principle,steady state characteristics,soft switching and soft start of a single DAHB converter in detail.The phase shift control is used as the control method of the converter,and the average mathematical model and Small-signal model,voltage closed-loop control system is designed,and the steady-state performance and dynamic performance of the converter are optimized using control theory,and verified by simulation.Next,this paper uses a two-module input-parallel-output-parallel(IPOP)system structure to solve the high-current stress problem of converters in high-power applications;analyzes the stability of parallel systems,and introduces common methods to achieve current sharing.The democratic current sharing control method is selected as the current sharing control method in this paper;combined with related literatures,the current-free sensor current sharing control is extended to the DAHB two-module parallel converter;the two current sharing control methods are simulated and verified,and compared and analyzed.Its advantages and disadvantages.This article designs a 500 W experimental prototype,with DSPTMS320F28335 as the core,and conducts soft switching,soft start,democratic current sharing control,sensorless current sharing control and anti-load disturbance experiments.Experiments have verified that the theoretical analysis of DAHB soft-switching and soft-start is correct.Democratic current sharing control and sensorless current sharing control are feasible and effective.The prototype has good dynamic performance and steady-state performance.The efficiency of the prototype was estimated.