Novel input current ripple compensation technique for capacitor-less dual-half-bridge converter

This paper proposes a repetitive controller to be used for capacitor-less current-fed dual-half-bridge (CF-DHB) converters under the grid-connected environment. When the dc-link capacitor is very small, the dc-link current fluctuation can distort the input current severely. Compared with the previous controllers introduced to reduce the input current ripples, the proposed repetitive controller can reduce them more significantly. In developing the proposed controller, we derived the dynamic model of the capacitor-less CF-DHB in the grid-connected environment, and used it to implement the repetitive controller. Experimental results verify that the proposed control scheme achieves desirable performance.