Switching Sequence-and Switching Transition Control of Power Electronic Systems

In this dissertation, first, an approach for switching sequence (SS)-based control (SBC) for a high frequency higher-order power electronic system (PES) is delineated. This type of control contrasts with a conventional linear-control design of a power-electronic system (PES) where the gains of the control laws are typically determined by small-signal analysis of the averaged model of the PES. The closed-loop control of such a PES using its small-signal model is often found to be unsatisfactory regarding the overall stability and performance, particularly when catering to non-linear time-varying and reduced damped loads. By employing some novel modeling and online optimization techniques, SBC, hence, attempts to control such challenging loads using industrial-scale DSPs and wide bandgap (WBG) GaN-FET and SiC based hardware set-ups. Then this dissertation investigates whether SBC can autonomously shape the conducted EMI spectra of a PES. It is shown by experimental results how SBC does complete differential-mode and reduced-scale common mode EMI mitigation for the PES while maintaining perfect state regulation for the higher-order non-minimum phase PES. This active EMI mitigation by SBC helps in operating the ultra-fast-transition recent wide-bandgap semiconductor devices at higher power with increasing switching frequencies, which is usually desirable for increased power density and reduced switching losses. Finally, the dissertation goes beyond switching sequence synthesis to performing switching transition control (STC) for shaping the rise-and fall times of the switching sequences of the WBG devices. This is done to investigate whether optimality can be created between higher transition speeds of WBG devices and EMI/device stress, to positively impact PES efficiency.