Application Summarization of Coupled Inductors in DC/DC Converters

Coupled inductor is one of the main components in power electronics circuits, which plays an important role in DC/DC converters. The leakage inductance of the coupled inductors can be employed to control the diode current falling rate and to alleviate the diode reverse-recovery problem. Then, some soft switching solutions are realized by the coupled inductor to reduce the switching losses. Furthermore, the coupled inductor can be operated in transformer mode to avoid the extreme duty cycle and to reduce the current ripple in high step-up or step-down conversion. However, the leakage inductance of the coupled inductors may induce high voltage spikes, which will increase the switch voltage stress, result in serious EMI noise and reduce the system efficiency. Even, it will break down the circuit. In one word, the coupled inductor is a two-side sword, which we should consider carefully. The applications of the coupled inductor in DC/DC converters are summarized and classified in this paper. A systematic discussion is given to focus on the performances of the coupled inductor in DC/DC converters. This paper would like to provide a useful framework and point of reference for future applications of the coupled inductor in DC/DC circuits.