Digital Autotuning

Numerous advances have been made in the area of practical autotuning digital control algorithms and implementation techniques. In this chapter, after a brief introduction to digital autotuning, a summary of programmable PID structures is presented. Two autotuning techniques are discussed in detail: an injection-based approach, a relay feedback-based approach. Practical implementation issues are briefly discussed. In the techniques discussed in this chapter, the converter is feedback-controlled at all times. The chapter also talks about the theory of digital relay feedback operation, as well as a method proposed in the literature to use it as a digital autotuning method for dc-dc switched-mode power converters. The chapter discusses only closed-loop autotuning techniques, in which the power converter is feedback-controlled at all times. In the relay feedback autotuner, the perturbation is a limit cycle triggered by the insertion of a strong nonlinearity inside the feedback loop.