基于反激拓扑的高效率太阳能微型单级并网逆变器

High efficiency solar energy single-stage grid-connected micro-inverter based on flyback topology

针对使用中央逆变器及组串式逆变器的光伏发电系统中整体太阳能转换效率不高的缺点,提出了将单个太阳能电池板连接一个小功率的逆变器以组成光伏系统,该系统能够使每个太阳能电池板都工作于最大功率点,针对该系统设计了基于反激拓扑的高效率单级并网逆变器,通过电流峰值控制,将太阳能电池板发出的直流电变换成与电网电压幅值匹配的正弦馒头波,再通过工作于工频状态下的晶闸管桥臂换相成正弦交流电,并入电网,锁相采用过零点检测法,最大功率点跟踪(MPPT)算法采用扰动法,给出了控制框图,并搭建了100 W的实验样机。研究结果表明,基于反激拓扑的单级并网逆变器与单个太阳能电池板组成的光伏系统可以有效地提高整个光伏发电系统的太阳能转换效率。

Aiming at raising the efficiency of the whole photovoltaic （PV）generating system, a low-power inverter was introduced to individually mount on each photovohaic module to form a system. In this system, each PV module can work at the maximum power point. A micro-inverter based on flyback topology using single-stage grid-connected method was proposed for this system. The flyback was controlled to convert the direct current produced by the PV panel into a rectified sine wave through the peak current control, and then a SCR bridge was used to unfold the rectified sine wave to an alternative one. The zero detecting method was used to do the phase lock logic,the perturbation method was used to do the maximum power point tracking（MPPT）of the PV panel and the control block was given. At last,a 100 W prototype was presented. The experiment results show that the flyback based single-staged grid-connected system raises the efficiency of the whole PV generating system.