Abstract
LLC resonant converter which have features as high power density, high efficiency and low noise is widely used for consumer and industrial applications. Recently, LLC resonant converter with center tapped transformer is applied to industrial application such as FA (Factory Automation), because wide-input voltage range and high power density is required in this application. Accordingly, a problem of unbalanced secondary current for each half cycle becomes apparent. In this paper, the influence of coupling coefficient of center tapped transformer between primary and secondary to the unbalanced secondary current is investigated. As a result, an offset of magnetizing current by difference of the coupling coefficient occurs then the unbalanced secondary current are generated to cancel the offset.
