PID tuning strategies for boost converters. Optimal compromise between performance and noise amplification

This paper presents some PID tuning strategies for the control of boost converters, that exhibit non-minimum phase behavior. First, some simple model identification techniques based on the step response are presented. Then, a PID tuning technique based on the fixed robustness tuning line concept, developed by the authors, is revised and applied to the tuning of PID controllers for boost converters. The proposed techniques allow the user to freely select the desired robustness, defined as the maximum sensitivity (Ms). They also permit to find an optimal compromise between measurement noise amplification and performance, in terms of disturbance rejection and reference tracking. Some direct tuning equations are also proposed to directly compute the controller parameters using some measurements from an open-loop step test. No previous proposals in literature about PID tuning of boost converters allow the free selection of robustness and compromise between performance and noise amplification, as the proposed approach. Experimental validation on two real boost converter prototypes, one overdamped and one underdamped, show the superiority of the proposed approaches, measured in terms of robustness, disturbance IAE, settling time and overshoot in the step response, compared to the use of a theoretical model of the converter based on the component values. The experiments demonstrate a reduction in the overshoot from 50% to less than 5%, and a 30% reduction in the settling time compared to theoretical model-based tuning. The results of this paper are intended for those practitioners who design boost converters and want a simple tool to tune the PID controller for the converter.