模块化三相光伏逆变器及其分布式自适应升压控制策略

MODULAR THREE-PHASE PHOTOVOLTAIC INVERTER AND ITS DISTRIBUTED ADAPTIVE BOOST CONTROL STRATEGY

针对现阶段级联H桥二倍频电压纹波和功率失配所带来的一系列问题,提出一种基于四端口LLC的模块化三相光伏逆变器拓扑结构,可从根本上解决相间功率失配的问题,同时该拓扑能够抑制系统直流母线电压上的二倍频电压纹波。总结分析相内功率失配问题形成的本质原因,并提出一种分布式自适应升压控制策略,以提高系统应对相内功率失配的能力,扩展系统的稳定运行范围。分布式控制架构可减少各模块间的信息交互、降低控制系统的复杂性。仿真和实验验证了所提拓扑结构及控制策略的有效性。

Aiming at a series of problems caused by the cascaded H-bridge double-line frequency voltage ripple and power mismatch at the present stage,a modular three-phase photovoltaic inverter topology based on a four-port LLC is proposed to solve the inter-phase power mismatch problem fundamentally.Meanwhile,this topology is able to suppress the double-line frequency voltage ripple in the output power of the system.The essential reasons for the formation of the in-phase power mismatch problem is summarized and analyzed and an adaptive boosting distributed control strategy is proposed to improve the ability of the system to cope with the in-phase power mismatch and expand the stable operation range of the cascade system in the paper.The distributed control architecture reduces the information interaction between individual modules and reduces the complexity of the control system.Simulations and experiments verify the effectiveness of the proposed topology and control strategy.