Fixed and variable power angle control methods for unified power quality conditioner: operation, control and impact assessment on shunt and series inverter kVA loadings

The concept of power angle control (PAC) of unified power quality conditioner (UPQC) provides an effective way to utilise the full capacity of series inverter of UPQC. This study deals with the operation and control of UPQC with PAC under voltage sag and swell conditions. The power angle, a resultant angle between actual source voltage and resultant load voltage, is used as a control variable. Two new control approaches, namely, fixed power angle and variable power angle, are proposed. It is shown that these approaches can affect the overall kVA loadings of shunt and series inverters. A thorough investigation on these fixed and variable power angle methods is presented in this study. A Matlab/Simulink-based detailed simulation and digital signal processor-based experimental studies are discussed to evaluate the performance of proposed two methods.