光伏并网逆变器LCL滤波器参数优化设计

针对光伏并网逆变器LCL滤波器的大纹波电流和高频谐波损耗问题,分析了电感之和、电感比值和滤波电容值、谐振频率以及入网电流之间的关系,提出了一种LCL滤波器参数最优设计方法.分析了LCL滤波器的传递特性并建立了谐波等效模型,研究了滤波参数对谐振频率以及并网电流的影响,根据LCL滤波器的设计约束条件和光伏并网逆变器实例设计了一组最优参数,并进行了仿真研究.结果表明,提出的优化方案不仅能够有效抑制开关频率的高频纹波,还能减小电感取值和阻尼损耗.

Parameter optimization design for LCL filter of photovoltaic grid-connected inverter

In order to solve the loss problem of large ripple current and high-frequent harmonic wave in the LCL filter of photovoltaic grid-connected inverter, the relationship among the inductance summation, inductance ratio and filtering capacitance, resonance frequency and grid current was analyzed, and a parameter optimization design method for LCL filter was proposed. The transfer characteristics of LCL filter were analyzed, and the harmonic equivalent model was established. The influence of filter parameters on the resonance frequency and grid current was analyzed. According to the design restriction conditions and the example of photovoltaic grid-connected inverter, a set of optimal parameters were designed, and the simulation analysis was performed. The results show that the proposed optimization method can not only effectively restrain the high frequency ripple of switch frequency, but also reduce the inductance value and damping loss.