A dynamic voltage restorer (DVR) with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other. 1. Introduction Advanced industrials usually use electronic devices such as programmable logic controllers or power electronic drives in their devices. Power quality problems may affect the function of these devices. They could malfunction or trip through voltage disturbances. One of the most important power quality problems is voltage sag which is considered to be the most occurring issue in the power systems [1]. This phenomenon is specified as a sudden decrease in the voltage from 90% to 10% of rated voltage which lasts for half cycle to one minute. The main source of voltage sags are system faults, switching of heavy loads, or starting of large motors [2]. One of the best solutions to improve power quality is the dynamic voltage restorer (DVR). DVR is a kind of custom power devices that can inject active/reactive power to the grids. This can protect critical loads from disturbances such as sags or swells. Four DVR topologies are compared in [3]. In this paper, the DVR with no energy storage devices and load-side connected shunt converter is selected. By using a matrix converter instead of the AC/DC/AC converters in that topology, the DC-link and its bulky capacitor would be eliminated. Generally a matrix converter is a direct AC/AC converter. A three-phase matrix converter has nine bidirectional switches that are able to connect any output phase of the system to any input phase at any time [4]. Some advantages of the matrix converter are bidirectional power flow, controllable sinusoidal output voltage, ability to control the input power factor, and a compact structure. However the complexity of its control is its main drawback [5]. Different DVR topologies based on matrix converters are presented before. A flywheel-supported DVR controlled by the matrix converter is proposed in [6]. Another topology is studied in [7] that the behavior of a DVR with matrix converter utilizing Alesina-Venturini
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