基于LCL滤波器的双向储能变流器研究

Bi-directional power conversion system based on LCL filter

为了在中/大型功率并网系统中引入更具优势的LCL滤波器,必须采用特殊的控制策略对LCL滤波器引入的谐振峰加以抑制。从节省双向储能变流器系统成本的角度,提出了一种基于滤波电容电流内环、并网电流外环的双环控制策略。从主电路的参数设计、控制器的参数设计、控制器的性能分析3个方面对策略进行了详细的阐述,并给出了先内环后外环的参数设计方法。搭建了一台50 kW的双向储能变流器作为试验样机,通过实验证明了所提控制策略不仅可以保证LCL滤波器稳定工作,而且可以减小并网电流谐波。

When the more prevailing LCL filter is adopted in mid/high-power grid-connection system,special control strategy should be applied to suppress the resonant peak caused by it. A low-cost dual-loop strategy of the inner filter capacitor current control loop and the outer grid-connecting current control loop is proposed for bi-directional power conversion system,which is thoroughly discussed in three aspects：main circuit parameter design,controller parameter design and controller performance analysis. A parameter design method of inner-first-outer-last is given and a prototype of 50 kW bi-directional power conversion system is built. Experimental results verify that,the proposed control strategy ensures the stable operation of LCL filter and reduces the harmonic of grid-connecting current.