Experimental Evaluation of Internal Model Control Scheme on a DC-DC Boost Converter Exhibiting Nonminimum Phase Behavior

In this work, an internal model controller (IMC) with two-degree-of-freedom has been implemented as a voltage mode controller for the output voltage regulation of a boost-type dc-dc converter that exhibits nonminimum phase behavior due to occurrence of a right-half plane (RHP) zero. The IMC structure provides an alternate parameterization of the conventional feedback controller and is comparatively simple to tune to achieve satisfactory servo and regulatory behavior that are close to the performance limits set by the RHP zero. An internal model controller was designed using a linear model developed in the neighborhood of a nominal operating point for the converter. To assess the efficacy of the IMC scheme, simulation studies and experimental evaluations were carried. In majority of the problems investigated, the IMC was found to perform significantly better than a PID designed using the conventional approach. The responses obtained using the experimental setup were found to match closely with the responses obtained using the nonlinear dynamic model based closed-loop simulations, which corroborated the conclusions reached through the simulations. Thus, the simulation as well as experimental studies indicated that the IMC scheme is ideally suited for controlling a boost-type dc-dc converter exhibiting the nonminimum phase behavior.