Regulador De Tension Basado En Un Matrix Converter

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A Voltage Regulator Based on Matrix Converter for Smart Grid Applications
A. Garces, Member IEEE, and A. Trejos, Member IEEE,

Abstract—This paper presents a power electronics-based voltage regulator for distribution feeders. The topology of the regulator is based on three-phase matrix converters. Input power factor as well as output voltage are fully controlled by this regulator.Improvement in flexibility, controllability and voltage stability are demonstrated though simulations on a feeder part of the IEEE 123 nodes test distribution system. A discussion on the advantages and drawbacks of this technology for future smart grids applications is presented. Simulation results demonstrate the potential of this technology. Index Terms—Matrix converter, smart grids, voltage regulator.I. I NTRODUCTION OLTAGE regulators (VR) are important components in conventional distribution systems. They are used to rise the voltage level and improve voltage quality. VRs are commonly placed in long distribution feeders which are more susceptible to long-term voltage variations. Usually, VR are constructed using three single phase autotransformers which are controlled independently inorder to reduce the undesirable effects of unbalanced loads. Over the past century distribution voltage regulators have been based on transformers with tap changers. They have demonstrated to be an efficient and reliable technology which fulfill the requirements of conventional distribution systems. However, modern distribution systems require a more flexible operation which considers dynamic changes inload and generation. VRs operated in a conventional way cannot deal with these new challenges [1]. Therefore, new control strategies have been developed, some of them based on sophisticated artificial intelligence tools such as neural networks and fuzzy logic [2]. Even so, the increasing use of distributed generation makes VR with tap changers transformers insufficient for voltage regulation. Themain reason behind that is the discrete and slow operation of taps changers. In addition, a transformer can re-distribute three phase reactive power but not generate it. Indeed, demand of reactive power at the input of a VR increases, i.e power factor is reduced, whether tap is ajusted to
——————————————– This work was supported in part by Universidad Tecnologica de Pereira and InstitutoMetropolitano de Medellin. Alejandro Garc´ s Ruiz is with Faculty of Electrical Power Engineering of e the Universidad Tecnologica de Pereira (La Julita - Pereira, Colombia). Grupo de investigacion en sistemas electricos. Email: alejandro.garces@utp.edu.co Luz Adriana Trejos is with Grupo de Investigacion en Materiales Avanzados y Energia Instituto Tecnologico Metropolitano (Medellin - Colombia) Email:luztrejos@itm.edu.co

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rise the output voltage. Therefore, voltage stability is adversely affected. Low power factor in distribution feeders must be compensated using variable or fixed capacitors. However, capacitors are not a flexible solution. In addition, they can produce resonances in the system due to the increasing number of nonlinear loads in modern distribution systems. As a consequence ofthat, topologies based on power electronic converters must be developed. Matrix converter is a topology for direct AC/AC conversion that has demonstrated high efficiency and compact design [3]. In contradistinction to conventional AC/AC converters which require an intermediate stage of DC conversion, a matrix converter can achieve direct AC/AC conversion. An indirect AC/DC-DC/AC conversion (or backto back) implies the use of electrolytic capacitors to maintain a constant DC voltage. In addition to the cost, electrolytic capacitors present some disadvantages such as decreasing of the converter lifetime, and increasing of weight and volume. Direct AC/AC conversion is therefore more efficient and reliable than other type of converters. Topologies based on matrix converter have been used in...