Experimental Verification of Robust PID Controller under Feedforward Framework for a Nonminimum Phase DC-DC Boost Converter

This article addresses the disturbance rejection problem of a nonminimum phase dc-dc boost converter operating in the continuous conduction mode (CCM) using a novel robust proportional-integral-derivative (PID) controller design method. The proposed idea is to design the controller using the equivalent feedforward formulation of the modified direct synthesis (MDS) approach. The advantages of the proposed MDS design are: 1) systematic incorporation of disturbance dynamics and the converter dynamics explicitly in the controller design to reduce the complex tuning effort of the controller parameters; 2) allowing the converter to operate close to the performance limit set by the zero in the right half-plane (RHP); 3) the closed-loop performance specifications can be incorporated into the desired loop response using only single tuning parameter based on Bode's gain crossover frequency inequality; 4) attenuates the loop gain to improve the disturbance rejection; and 5) realization of controller requires only output voltage as a feedback signal. The strength of the proposed MDS method is compared with the internal model control (IMC) method in both simulations and experiments. Based on these responses, the proposed PID ensures robust performance to the model-plant mismatch and allows the output voltage to quickly recover back to the operating voltage in the presence of external disturbances with less inductor current.