To address the low voltage gain problem of traditional $Y$ source converter, the novel structure is proposed in which a series switched inductor structure adopted to further improve the step-up ability. Compared with the conventional improved Y-source topology, the proposed new topologies relocate the semiconductor from the high voltage location to the low voltage location, which effectively reduces the rated voltage of the switching device. Besides, and the topology combines different boost modules, which effectively improve the boost ability. Based on above analysis, the corresponding prototypes are built, as the experimental results shown, the step-up ability can be improved and also there is no large voltage spikes.