Research On Modular Three Port Converters

Three-port power conversion system has been widely used in new energy power generation,aerospace power systems. Three-port converter is becoming a hot topic due to its high power density,high efficiency, low cost. However control loop is coupled due to the reuse of power branch. In thispaper, the coupling is studied and approximate decoupling is achieved by quasi-decoupling controlstrategy. To further enhance the three-port converter power level and expand its scope of application,modularity is studied.A synchronous rectification half-bridge converter is researched. The working principle andclosed-loop control strategy is analyzed. The loop coupling is analyzed on the basis of small signalmodeling. A simple and effective decoupling control method is adopted and analyzed theoretically infrequency domain. Control loop can be rationally designed and optimized on the basis of loopdecoupling. Steady and dynamic performances are tested. The experimental results verify thecorrectness and effectiveness of the working principle, closed-loop control strategy and decouplingcontrol strategy.Modular three-port converters are researched and closed-loop control strategies and energymanagement strategies are adopted to realize rational allocation of power in multi-module parallelsystem under various conditions. At first, three-port converter three-port-paralleling (input port,storage port and output port in parallel) is researched. Paralleling system architecture, operating mode,closed-loop control strategies, energy management control strategy are analyzed. A test platform isbuilt to test steady and dynamic performance. Secondly, three-port converter two-port-paralleling isresearched, taking distributed power system (storage port and output port in parallel) and distributedload system (storage port and input port in parallel) as examples. Parallel operating rules, operatingmode, closed-loop control strategies and energy management strategies for paralleling systems areanalyzed. A simple and effective energy management control strategy is adopted. Experimentalplatforms for distributed power systems and distributed load systems are built respectively to teststeady and dynamic performance. Experimental results demonstrate the validity and effectiveness ofthe closed-loop control strategies and energy management strategies.