FE-UDC series is the new generation of small to medium power transformer-less UPS of FEFA. FE-UDC adopts new circuit design, and electrical performance is optimized. The series is with reasonable inside arrangement, the dimension of the units is small, and the power density is high. The appearance is simple and beautiful by design. Advanced design makes FE-UDC more reliable and high power efficient, and the reduce TCO (total cost ownership) in result. Miniaturization design reduces the transportation space and installation space, and this also make it easy to maintain the FE-UDC for customers. FE-UDC series can support lithium battery and this supplies more choices to customers.