Research On Current Sharing Control Algorithm Of Parallel Buck Converter System

With the development of modern industry,the requirements of power supply system are improved.The parallel Buck converter has been in widespread use because of high capacity.However,due to the limitation of the technology level and the systematic error,the parameters of the modules in the parallel Buck converter system are different,which leads to the inconsistency of the modules in parallel system.If the Buck converter modules are directly connected in parallel,it is difficult to ensure that the parallel system can share the load current,which seriously affects the stability and reliability of the system.Therefore,the current sharing problem has become a research focus in parallel power supply domain.The problem of current sharing control for parallel buck converter system is investigated in this paper.The centralized current sharing control and the distributed current sharing control are designed respectively.Firstly,to achieve the goal of sharing control and improve the systems dynamic performance,a new kind of finite-time current sharing control algorithm is designed and employed.Under the proposed control algorithm,rigorous proofs show that not only the output voltage of the converter system can reach the desired reference voltage in a finite time but also the objective of current sharing can be achieved within almost the same time.In addition,a finite-time load estimator is given and an adaptive finite-time current sharing control algorithm is subsequently developed.Secondly,different from centralized control,a distributed current sharing control algorithm is designed based on the multi-agent consensus theory.Distributed control system has no central controller,which making the system more intelligent and flexible.Based on the graph theory,the parallel Buck converter system is modeled as a multi-agent system,and the current sharing problem turn into a state consensus problem.The converter modules control themselves by communicate with neighbor to achieve the goal of sharing control.Under the distributed control algorithm,the stability of the parallel Buck converter system is strictly proved.Finally,the experimental platform is built to verify the validity of two control algorithms separately.