Robust current controller for three-phase inverter using finite-state automaton

A novel feedback current controller for a three-phase load driven by a power inverter is proposed. The main design specifications are robustness to load electrical parameters, fast dynamical response, reduced switching frequency, and simple hardware implementation. To meet previous specifications a multi-variable hysteresis type controller is proposed, designed as a finite-state automaton and implemented with a programmable logic device. After a general introduction, system analysis is performed, control targets are specified, and the proposed control strategy is presented and discussed. Further, actual controller architecture, based on simple analog-logic hardware, is shown and experimental results are presented using an induction motor as the inverter load. However, this does not limit the wider applicability of the proposed controller that is suitable for different types of three-phase AC loads