Overview of Common-mode Noise Cancellation Techniques for Isolated Power Converters

With the application of wide-bandgap devices and planar transformers in isolated power converters, the converters exhibit high dv/dt and large parasitic capacitance, and severe common-mode (CM) noise is generated. As a general approach to attenuating the CM noise, passive CM electromagnetic interference (EMI) filters occupy a considerable volume and weight of the system. Therefore, various CM noise cancellation techniques have been proposed to reduce the size of CM EMI filters. In this overview, four basic groups of CM noise cancellation techniques are reviewed: (1) reduction of CM parasitic capacitance, (2) adjustment of the transformer winding structure, (3) optimization of circuit configuration, and (4) addition of cancellation circuits. The advantages, disadvantages, and relationships between these techniques are systematically summarized, and future work is discussed.