Implementation of an internal model controller with anti-reset windup compensation for output voltage tracking of a non-minimum phase dc-dc boost converter using FPGA

Abstract

In this work, output voltage tracking problem of non-minimum phase (NMP) boost type dc-dc converter in continuous conduction mode (CCM) is studied under the internal model control (IMC) framework. If it is desired to implement large set-point changes, then the manipulated inputs can get saturated during the transients and the closed-loop performance can deteriorate if no provision is made for anti-reset windup. To deal with the reset windup caused by the input saturation, an anti-windup compensator is introduced within the IMC framework, which consists of a first order filter that becomes active only after input saturation occurs. Tuning guidelines are provided for selecting the filter parameters. The efficacy of the modified IMC method has been verified using MATLAB simulations of a boost type dc-dc converter. To assess feasibility of integrating the proposed approach with real applications, hardware experiments were carried out using an FPGA based module (NI-CompactRIO-9104) on the prototype boost converter. The simulations studies as well as the experimental evaluations clearly indicate that, with reference to the input behaviour obtained without anti-windup compensation, the input quickly desaturates when the modified scheme is employed and this leads to significant improvement in the closed-loop responses.