One-sensor current sharing in multiphase interleaved DC/DC converters with coupled inductors

To improve the efficiency and to reduce the volume of dc-dc converters and their filters, interleaved converters are used. For further reduction of the inductor volume, coupled inductors can be applied. In these multiphase converters, appropriate active current sharing is necessary due to the inherent current unbalance caused by the parameter deviations of the components and the duty cycles of the phases. The common method to realize current sharing is to use a single current sensor for each phase whereas the current in each phase is controlled independently. Due to the costs of the current sensors, a reduction of the quantity is desirable. In this contribution, a method is presented which allows the current sharing by means of only one current sensor without extra circuitry and computation effort. This method is analyzed exemplarily for the application in a threephase interleaved converter with coupled inductors in theory and practice. Successful operation can be stated.