DC/DC多模块串并联组合系统控制策略

Control Strategy for DC/DC Multiple Modules Series-Parallel Combined Systems

将多个标准化DC/DC变换器模块的输入和输出分别串联或并联,可以得到四类多模块串并联组合系统,分别可以有效地适用于不同的应用场合。针对四类DC/DC多模块串并联组合系统,本文分析了各模块的输入均压/均流与输出均压/均流的内在关系并确定了每类组合系统的控制对象。对于输入并联型系统,既可以采用输入均流控制,也可以采用输出均流控制(输入并联输出并联型系统)或者输出均压控制(输入并联输出串联型系统),而对于输入串联型系统,只能采用输入均压控制。在此基础上,提出了一种新的控制策略,实现了输入均压/均流(输出均压/均流)控制与输出电压控制的解耦,经进一步推导,该控制策略还可以实现串并联组合系统的模块化,不需要额外的控制环节。最后以三台全桥变换器的串并联组合系统实验验证了该控制策略的有效性。

DC/DC series-parallel combined systems, in which multiple standardized converter modules are connected in series or parallel at the output and input sides, can be classified into four possible architectures. Each architecture has its own specific application areas. This paper analyzes the inherent relationships between the input voltage/current sharing and the output voltage/current sharing of the four combined systems and finds out the control objects for each system. For the input-parallel combined systems, both input currents sharing control and output currents sharing control （input-parallel output-parallel） or output voltages sharing control （input-parallel output-series） can be adopted. For the input-series combined systems, only input voltages sharing control can be adopted. Based on the analysis, a general control strategy for series-parallel combined systems is proposed, which decouples the input/output variables sharing control loops and output voltage control. Furthermore, the control strategy can achieve modularization architectures for series-parallel combined systems without added controller to regulate input/output variables sharing. A prototype composed of three full-bridge converters is built to validate the effectiveness of the proposed control strategy.