Low Common Mode Noise Cellular RDCX with Single Bus Multi-Level Regulator

The Cellular Regulated DC Transformer (RDCX) is capable of achieving voltage regulation while maintaining high efficiency. However, low-frequency common mode (CM) noise will be introduced by the PWM regulator through inter-winding capacitance of the DCX transformer, leading to a large CM filter size. This paper proposes a novel low CM noise cellular RDCX topology with single bus multilevel regulator. Compared with the original cellular RDCX converter, CM noise can be reduced without sacrificing the efficiency and power density. A 2.3kW prototype with 400 V input and 250–450 V output voltage range is built to verify the analysis. The proposed Cellular RDCX converter achieves over 60 dB reduction in CM noise with over 800W/in ³ power density.