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

PAN Ming-hang， SU Xiu-rong， WANG Zheng-shi
（College of Electrical Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： Aiming at raising the efficiency of the whole photovoltaic（PV）generating system，a low-power inverter was introduced to individually mount on each photovoltaic 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.
Key words： inverter； flyback topology； grid-connected； photovoltaic（PV）； maximum power point tracking（MPPT）