Unified Power Quality Conditioner for Power Quality Improvement with Induction Motor Drive

Abstract

In this paper presents Three-phase unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase  Voltage Source Inverter (VSI), The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. Dynamic Voltage Restorer (DVR) is presented to improve the Power quality in distribution system by injecting voltage in series for the protection of sensitive loads against voltage sags and voltage swells. The performance of the DVR depends on control technique involved .This circuit consists of capacitor in series with the interfacing inductor of the shunt active filter. The series capacitor enables reduction in dc-link voltage requirement of the shunt active filter and simultaneously compensating the reactive power required by the load, so as to maintain unity power factor, without compromising its performance. This allows us to match the dc-link voltage requirements of the series and shunt active filters with a common dc-link capacitor. AC induction motor has a fixed in the output side to run the ac machine with required speed. The proposed topology enables UPQC to compensate voltage sags, voltage swells and current harmonics with a reduced DC-link voltage without compromising its compensation capability by implementing the circuit in MATLAB/SIMULINK software.