Computationally efficient fixed-parameter digital control of power converters

This paper studies the effect of variable sampling frequency on the dynamic of the fixed-parameter digital compensator in switched-mode power supplies. Based on the resulting analysis, we propose a simple technique to design a computationally efficient adaptive predictive functional controller (PFC) which can be implemented in a low-cost micro-controller. While the approach should have general applicability to systems where the sampling/switching frequency is varied, in this paper we use the example of a flyback power converter operating in discontinuous conduction mode (DCM). The performance of the proposed controller is verified with both simulation and experimental results.