Improved Set-point tracking and Disturbance Rejection of DC-DC Converters using Voltage-Mode Digital Control

Abstract

In this work, a voltage-mode control scheme with a two-degrees-of freedom is developed for improving servo and regulatory responses of a boost type dc-dc converter operated in continuous conduction mode. The servo behaviour is shaped using two model based digital controllers, namely modified Dahlin’s controller (MDC) and the Vogel-Edgar controller (VEC). To handle input saturation during the transients, a novel anti-reset windup scheme is proposed and integrated with VEC and MDC. To improve the regulatory response, without altering the design of VEC or MDC, a model based robust internal-loop compensator (RIC) is introduced which attempts to reject unmeasured disturbances before the feedback controller can start reacting to their effects. To assess efficiency of the proposed integrated control scheme, simulation studies and experimental verifications have been carried out for a variety of servo and regulatory scenarios. Analysis of simulation results reveals that, if tuning parameters of the RIC are chosen judiciously, then the proposed scheme significantly improves regulatory behaviour of VEC and MDC without significantly altering their servo behaviour. The closed-loop responses obtained in the experimental evaluations closely resemble the responses of simulations and corroborate conclusions reached through analysis of simulation results.