Robust PI controller for multi-purpose voltage controlled VSI

This paper proposes the novel tuning method for PI controller parameters for three-phase voltage source inverter (VSI) which imparts robust stability and optimized performance to the system. Resonated output filter is actively damped using filter capacitor current current feedback. Selective damping technique is proposed to exclusively target the low frequency harmonics within bandwidth. From a set of controllers which ensures asymptotic stability the controller is extracted by optimizing the H_∞ norm of sensitivity function (Robust PI Controller). The designed controller provides robust stability against parametric uncertainties and disturbances with optimum tracking performance. The analysis and performance are validated with simulation and experimental results on 110 Vac/1.5 kVA three phase inverter, feeding a non-linear rectifier load.