Planar transformer shows great benefits when applied in a high efficiency and high power density LLC converter with plenty of increased common-mode noise which is mainly caused by the large interwinding capacitances. For the shielding design of LLC converter with full bridge rectifier (FBR), the static-electric-potential point is important and the voltage potential difference between shielding and primary/secondary windings should make displacement CM current equals to zero or the net CM current equals to zero. Different strategies of shielding design were analyzed and compared on an HBLLC converter with FBR. The CM noise of different strategies are measured based on a 1.5kW HBLLC converter with FBR hardware platform. The EMI measurement results show the proposed strategy of EMI shielding design can attenuate the CM noise by around 20 dB.
