Inductor Coupling and Integration for 6.6kW On Board Battery Charger
For many years, the coupled inductor has been widely adopted in VR applications be-cause of its benefits such as reducing current ripple or improving transient performance. Previously, the negative coupled inductor was applied to the interleaved MHz totem-pole CRM PFC converter for server power supply. In this paper, the positive coupled inductor concept is applied to the interleaved totem-pole CRM PFC converter for a 6.6kW on board battery charger and the difference between negative coupling and positive coupling will be discussed. The benefits of positive coupling for the battery charger, such as reduc-ing the switching frequency range and reducing the input DM noise will be presented, thus showing that the positive coupled inductor can improve the performance of the PFC converter. In addition, a balance technique is applied to help minimize the CM noise. Pre-viously, the balance technique was developed for an interleaved boost PFC converter with independent inductors. This presentation will introduce how to achieve balance with a coupled inductor. Last but not least, the inductor will be integrated into a PCB winding with little sacrifice on loss. With the inductor integration, the converter can avoid labor intensive production and achieve a fully automatic manufacture.