Robust Digital Voltage-Mode Controller for Fifth-Order Boost Converter

In this paper, a robust digital voltage-mode controller (DVMC) is proposed for a fifth-order boost point-of-load converter. Salient features of the proposed topology are compared with a conventional boost converter. Mathematical models are formulated using a discrete-time modeling technique and then employed in the compensator design, which uses the digital direct design approach. The DVMC is designed to ensure load voltage regulation. Robustness theory is applied directly in the digital domain, and then, various robust stability criteria describing sensitivity functions are formulated. The controller is designed to satisfy robustness criteria and then evaluated over a range of disturbances in spite of the fact that it maintains regulation. To confirm this, design simulations have been carried out on a 25-W 12-36-V converter system. Experimental results are provided to validate the concept and also to verify the range over which the designed controller is robust.