Robust digital voltage-mode controller for synchronous soft-switching boost converter

In this paper robust digital voltage-mode controller design for a synchronous soft-switching boost converter is presented. Although it is a boost converter, but due to soft-switching nature the converter circuit exhibits five different modes of operations in one switching cycle and also results in zero-voltage transition to the switching devices. As there are several operating modes the small-signal z-domain transfer functions are formulated using system identification toolbox of the MATALB, and then used in the direct digital controller design. A pole-zero placement technique is adopted to arrive at final digital voltage-mode controller and then an edge theorem is employed for testing the robustness of the controller. Closed-loop converter performance is predetermined for a 25 to 100 V, 50 Watt prototype in simulation and then compared with experimental measurements. Experimental measurements are in close agreement with simulations.