Fuzzy logic design of self-tuning switching power supply

This paper presents the design of a variable-voltage DC source using proportional and integral (PI)-like fuzzy logic controller (FLC). Three types of topology (buck converter, boost converter, and buck-boost converter) are used to step down, step up, and negate the input voltage. The output voltage of the proposed scheme can be adjusted automatically according to the pre-set reference DC voltage. PC implementation of the controller offers great flexibility in both the design and maintenance phases. Both simulations and experimental results are provided to verify the theoretical analysis through an experimental prototype of the proposed controller. The closed-loop performance of simple variable-voltage DC source is investigated for buck, boost and buck-boost converters in respect to load regulation and line regulation. The controller shows very interesting tracking features and is able to cope with load changes and input voltage variations. The proposed controller structure is general and can be directly applied to any DC–DC converter topologies.