中文摘要：

基于串联型优化器结构的光伏并网系统能够有效解决部分遮挡以及光伏组件不匹配导致的热斑效应,从而提高分布式光伏并网系统的输出功率。针对直流母线上100 Hz电压纹波影响并网电流质量的问题,对集中式逆变器的拓扑、控制策略、环路设计等方面进行了研究。设计了一种应用于集中式逆变器的双环控制器,电压外环稳定直流母线电压,电流内环控制并网电流。分析了直流母线电压100 Hz纹波对控制环路的影响,提出了一种电压环纹波补偿的控制策略,通过输入/输出功率、母线电容与电网相位的关系计算电压纹波的大小与相位,从而补偿电压外环的纹波干扰。研究结果表明,该方法可以有效减小直流母线电容,同时降低并网电流的总谐波失真（THD）。

英文摘要：

Solar system based on series-connected optimizer structure is effective to solve the hot spot effect and increase output power when partial shading or mismatch between photovoltaic panels. Aiming at the influence on the output current that is exerted by 100 Hz voltage ripple on the DC bus, the topologies, control strategy and loop design of the central inverter were investigated. A double loop control strategy was designed for the central inverter which includes an outer voltage loop to maintain the DC bus voltage and an inner current loop to regulate the grid current. The relation of 100 Hz voltage ripple to control loop was analyzed, in addition a novel control method of compensating the voltage ripple in the voltage loop was proposed, that was to calculate the ripple value and phase by the grid phase, bus capacitance, output and input power, thereby compensating the ripple interference in the voltage loop. The results indicate that the method can decrease DC bus capacitance effectively, meanwhile depress the output current THD.