Performance analysis of an adaptive Gaussian nonlinear PID control applied to a step-down CC-CC converter

Abstract

In several industrial systems, designers have mainly explored topology variations, which are the case of space-vector control systems of electrical machines or active filters and power electronic converters, where the control loops still have traditional PID controllers. As the possibilities of topologies have been very explored, designers are turning attention towards nonlinear control schemes. However, in complex systems, the change of PID controllers to others nonlinear may be a very difficult task, and may require structural changes in the control system, like changing to fuzzy, sliding mode or others, and an exhaustive search for the optimal parameters. This work proposes an adaptive PID control based on gaussian functions, which are functions that presents predefined higher and lower limits, adjustable concavity, are smooth and without discontinuities. This means that little or no structural adjustments need to be made to the system. The optimal parameters are obtained by making a parametric sweep of the gaussian functions, where resulting setling-time and overshoot are considered. A comparison of simulation and experimental resutls are presented using a Buck converter with the controller implemented in an FPGA.