Instantaneous power theory based Unified Power Quality Conditioner (UPQC)

Abstract: This paper presents a comprehensive review on the unified power quality conditioner (UPQC) to enhance the electric power quality at distribution levels. This is intended to present a broad overview on the different possible UPQC system configurations for single-phase (two-wire) and three-phase (three-wire and four-wire) networks, different compensation approaches, and recent developments in the field. It is noticed that several researchers have used different names for the UPQC based on the unique function, task, application, or topology under consideration. Therefore, an acronymic list is developed and presented to highlight the distinguishing feature offered by a particular UPQC. In all 12 acronyms are listed, namely, UPQC-D, UPQC-DG, UPQC-I, UPQC-L, UPQC-MC, UPQC-MD, UPQC-ML, UPQC-P, UPQC-Q, UPQC-R, UPQC-S, and UPQC-VA. More than 150 papers on the topic are rigorously studied and meticulously classified to form these acronyms and are discussed in the paper.

Abstract: The paper proposes the application of constant frequency unified power quality conditioner to overcome the power quality issues in fixed speed wind mill connected with the micro grid The power circuit of a constant frequency unified power quality conditioner (CF-UPQC) is based on a combination of UPQC, and frequency regulator (matrix converter) This equipment incorporates compensation functions like voltage sag, voltage swell, reactive power compensation, current harmonic rejection, and also provides frequency regulation Integrated series and parallel active filter (UPQC) is a universal solution for the most power quality problems The main drawback is that it cannot regulate the supply frequency variation Here CF_UPQC the matrix converter is used for frequency regulation This integration, the compensator compensates all the power quality issue for fixed speed induction wind generator Simulation results are presented to confirm that this approach has better performance over the existing power quality conditioners for FSIWG connected with micro grid

Abstract: The conventional reactive power in single-phase or three- phase circuits has been defined on the basis of the average value concept for sinusoidal voltage and current waveforms in steady states. The instantaneous reactive power in three-phase circuits is defined on the basis of the instantaneous value concept for arbitrary voltage and current waveforms, including transient states. A new instantaneous reactive power compensator comprising switching devices is proposed which requires practically no energy storage components.

Abstract: Active filtering of electric power has now become a mature technology for harmonic and reactive power compensation in two-wire (single phase), three-wire (three phase without neutral), and four-wire (three phase with neutral) AC power networks with nonlinear loads. This paper presents a comprehensive review of active filter (AF) configurations, control strategies, selection of components, other related economic and technical considerations, and their selection for specific applications. It is aimed at providing a broad perspective on the status of AF technology to researchers and application engineers dealing with power quality issues. A list of more than 200 research publications on the subject is also appended for a quick reference.

Abstract: This paper deals with unified power quality conditioners (UPQCs), which aim at the integration of series-active and shunt-active power filters. The main purpose of a UPQC is to compensate for voltage flicker/imbalance, reactive power, negative-sequence current and harmonics. In other words, the UPQC has the capability of improving power quality at the point of installation on power distribution systems or industrial power systems. This paper discusses the control strategy of the UPQC, with a focus on the how of instantaneous active and reactive powers inside the UPQC. Experimental results obtained from a laboratory model of 20 kVA, along with a theoretical analysis, are shown to verify the viability and effectiveness of the UPQC.

Abstract: The power circuit of a general active power line conditioner (APLC) is based on series and shunt power converters that share a single DC link. In the present paper, a generic control concept for these series and shunt converters is proposed. It is based on the instantaneous real and imaginary power theory. In fact, the resulting equipment deals with the custom power and FACTS concepts. This equipment incorporates not only the compensation functions at the fundamental frequency like a unified power flow controller (UPFC), but also provides active harmonic mitigation capabilities. For these reasons, the compensator proposed here is called the universal active power line conditioner (UPLC). Simulation and experimental results are presented to confirm that the new approach has better performance than those obtained by controllers based on traditional concepts of active and reactive power.

Abstract: This paper presents a novel philosophy to compensate the load-reactive power demand through a three-phase unified power quality conditioner (UPQC). Most of the UPQC-based applications show the dependency on shunt inverter for load-reactive power compensation, whereas the series inverter is always looked as controlled voltage source to handle all voltage-related problems. This paper proposes a new functionality of UPQC in which both the shunt and series APFs supply the load-reactive power demand. This feature not only helps to share the load-reactive power demand, but also helps to reduce the shunt APF rating, and hence, the overall cost of UPQC. This results in better utilization of the existing series inverter. The theory and complete mathematical analysis termed as ldquopower angle control (PAC)rdquo is presented. The simulation results based on MATLAB/Simulink are discussed in detail to support the concept developed in the paper. The proposed approach is also validated through experimental study.