Low Common-Mode Noise LLC Resonant Converter With Static-Point-Connected Transformer

A new structure of the transformer and its winding layout are proposed to reduce the common-mode (CM) noise generated from the planar transformer (PT). In the proposed converter, two half-bridgeLLCresonant converters are connected in parallel on the primary side, and the secondary side of them is connected in series. The proposed converter can be utilized for the medium-to-high power applications due to the full-bridge structure of the primary side. For each transformer, one of the terminals is connected to the static point, which has zerodv/dtcharacteristic. Thus, the primary-side layer can have the samedv/dtcharacteristics with the secondary-side layer. By adjacently locating the primary and secondary layers, which have the samedv/dtcharacteristic, the CM current and noise generated from PT can be significantly reduced. Therefore, the proposed converter can achieve a high power density by reducing the size of the electromagnetic interference filter.