The Transformerless Single-Phase Universal Active Power Filter for Harmonic and Reactive Power Compensation

Abstract

This paper presents an universal active filter for harmonic and reactive power compensation for singlephase systems applications. The proposed system is a combination of parallel and series active filters without transformer. It is suitable for applications where size and weight are critical factors. The model of the system is derived and it is shown that the circulating current observed in the proposed active filter is an important quantity that must be controlled. A complete control system, including pulse-width modulation (PWM) techniques, is developed. Comparisons between the structures are made from weighted total harmonic distortion (WTHD). Steadystate analysis are also presented in order to demonstrate the possibility to obtain an optimum voltage angle reducing the current amplitude of both series and parallel converters and, consequently, the total losses of the system. Simulated and experimental results validate the theoretical considerations.

Three‐phase four‐wire unified power quality conditioner structure with independent grid current control and reduced dc‐bus voltage operating with inverted/dual compensating strategy

“…Non‐sinusoidal currents and voltages references have been used to control the most UPQC applications . Therefore, it is indicated to employ any method for extraction the reference quantities …”

“…To overcome the most problems related to PQ, single‐phase and three‐phase series‐parallel active power‐line conditioners, known as unified power quality conditioners (UPQC), have been employed in there‐phase three‐ and four‐wire systems (3P3W and 3P4W) by means of different configurations and control strategies.…”

Transformerless Single-Phase Universal Active Filter With UPS Features and Reduced Number of Electronic Power Switches

“…The demonstration of this current can be seen in appendix of [16]. From the point of view of the controllers, the voltages:…”

“…Cost reduction is also achieved by eliminating passive components such as inductors, capacitors and transformers. Reducing the numbers of switches and passive elements in Active Power Filters (APF) and Uninterrupted Power Supplies (UPS) topologies not only reduces the cost of the whole system but also provides some other advantages such as great compactness, smaller weight, and higher reliability [12], [13], [14], [15], [16], [17]. However, the cost reduction requires the use of more complex control strategies.…”

A control scheme to improve the power quality with the absence of dedicated compensation devices in microgrid

“…On the other hand, distributed generation sources can be modeled as non-linear loads [4]. An effective method for harmonic suppression is harmonic compensation using passive [5][6][7][8], active power [9][10][11] and hybrid compensator filters [12][13]. Passive filters have the features of low cost and good efficiency and have been widely used to absorb harmonic current of nonlinear loads.…”