Optimal Trade-Off Capable Type-III Controller Design via PSO for Multiport Buck Converters

This study presents a particle swarm optimization (PSO)-based approach for designing an optimized Type-III controller for a nonisolated coupled-inductor dual-input bipolar triple-output buck converter (CI-DITO-BC). The methodology is applicable to any CI-based multiport dc–dc converter using voltage-mode control (VMC), addressing issues like cross-coupling and cross-regulation by ensuring decoupling and stability. The PSO algorithm uses the integral time absolute error (ITAE) as the objective function, a performance criterion known for providing the fastest response with minimal overshoot. The optimization incorporates ITAE across multiple transfer functions, minimizing the aggregate index to determine optimal controller parameters. This approach offers flexibility for designers, allowing tradeoffs between ITAE errors of different transfer functions to optimize overall system performance. Notably, this work fills a research gap by introducing the novel use of ITAE index across multiple transfer functions in multiport dc–dc converters, a methodology not previously explored. The design guidelines are validated through simulations using LTspice and MATLAB. Experimental results from a prototype CI-DITO-BC, which converts 12 V to 3.3 V, -3.3 V, and 6 V with 2.5 A load current capability, further validate the proposed approach. The proposed control circuit, based on VMC, employs fewer operational amplifiers than the current-mode control techniques reported in the literature, resulting in a simpler implementation while delivering comparable or even superior performance.