Conventional photovoltaic (PV) power system connects hundreds and thousands of solar cells to form the PV array to match the power and voltage rating. It has been reported that any mismatch among cells results in significant power loss. PV modular level parallel inverter (MLPI) has attracted significant research attention in order to address the issue and improve system reliability. The MLPI requires high voltage conversion ratio to step up voltage from the PV module level to the grid standard. Research has focused on the reduction of cost and efficiency enhancement. Up to date, the topology of flyback has been proved to be an effective solution for academic research and industrial application. Different configuration and topology have been proposed to achieve the highest solar energy harvest. This paper reviews the topologies and prove the concept by using simulation. The comprehensive review and simulation are intended to help readers understand the latest developments of the technology and inform research directions.