This paper presents a novel structure of high step-up DC/DC converters intended for distributed generation systems such as fuel cells and photovoltaic (PV) systems. Proposed topologies integrate the classical Y-source impedance network with different step-up cells to acquire strong boost ability which is unmatched by existing impedance networks. Compared to Y-source, proposed converters reserve versatile feature while need small shoot through duty cycle to obtain the same voltage gain. Basic operating principles are analyzed mathematically. Comparisons are made to highlight good performance. A 100W lab prototype is build up to verify the feasibility. Experimental results are provided to demonstrate theoretical analysis and correctness of calculations.