Design of Robust PID Controller Using PSO-Based Automated QFT for Nonminimum Phase Boost Converter

This brief reports a novel method of synthesizing a robust PID controller for regulating boost DC-DC converter that exhibits non-minimum phase (NMP) dynamics and complex-conjugate poles in its linear model. The NMP dynamics restrict the achievable closed-loop bandwidth and make tuning of PID parameters a difficult task. To solve this problem, the proposed design method uses the Quantitative Feedback Theory (QFT) in conjunction with particle swarm optimization (PSO) to carry out automatic loop-shaping. Due to the global optimization capability of PSO, the proposed multi-objective function approach with PID simplifies the loop-shaping to compensate the converter having complex-conjugate zeros. An attractive feature of this design method is that it accounts for the worst-case scenario due to parametric variations in the converter model. The real-time simulation results and the experiments reveal the efficacy of the proposed method.