An improved PID controller for switching converters

This paper describes the design and construction of an improved PID controller for a DC-DC buck converter working in Continuous Conduction Mode (CCM). The converter operates at a switching frequency of 1MHz. The lead-lag controller is first designed on the basis of classical theory of control systems using root-locus technique. The controller is then equivalently converted into a PID controller. The application of the derivative part of the PID controller on the output voltage signal rather than on the output voltage error signal reduces both the maximum percent overshoot and the settling time. The modified but improved form of PID controller is known as PID controller with Derivative on Output Only (PID-DOO). The analog PID controller is converted into a digital controller for the easier implementation. MATLAB/Simulink based simulation results are presented to validate the design procedure.