Model Predictive Control of Unified Power Quality Conditioner for Power Quality Improvement

This paper presents a model predictive control (MPC) design for the unified power quality conditioner (UPQC), an integration of series and shunt active filters to improve power quality in a power distribution system. The control strategy aims to regulate the load voltage and the source current to the desired references in spite of the existence of harmonic components in the supply voltage and the load current, possible sag or swell in the supply voltage, and non-unity power factor of the supply side. Kalman filters are used to extract the fundamental as well as the harmonic components abovementioned, which will then be used to formulate the desired references and regarded as measurable disturbances, respectively. Based on a state-space model developed for the UPQC, an MPC controller is designed. Simulation studies on a single-phase power distribution system are also presented to verify the performance.