A Novel Control Approach for Unified Power Quality Conditioner Q without Active Power Injection for Voltage Sag Compensation

This paper presents a new, simple and effective approach to estimate the required quadrature injected voltage during utility voltage sag condition. This approach helps in voltage sag compensation through reactive power control using series part of unified power quality conditioner, generally termed as UPQC-Q. Thus utility sag compensation can effectively be done without utilizing any active power from source or from inverter side. Moreover, this quadrature voltage injection during voltage sag compensation also helps to improve the source side power factor, which results in reduced shunt active power filter (APF) loading. The voltage harmonic compensation based on d-q transformation simultaneously with voltage sag compensation is also presented. The simulation results based on MATLAB / SIMULINK are discussed to validate the theory presented in the paper.