VOL. 10, NO. 22, DECEMBER 2015 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2015 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 17070 MATRIX CONVERTER: A REVIEW Nur Wahidah Basri, Hamdan Daniyal and Mohd Shafie Bakar Sustainable Energy & Power Electronics Research Cluster, Fakulti Kejuruteraan Elektrik & Elektronik, UNiversiti Malaysia Pahang, Pekan, Pahang, Malaysia E-Mail: nurwahidahbasri@gmail.com ABSTRACT Matrix Converter (MC) fundamentals and operation is described throughout this paper. This covers topological characteristics, MC types and basics of operation, implementation of discrete semiconductors as bidirectional switches, commercially available bidirectional switches modules packaging, bidirectional switches commutation schemes based on current and voltage direction as well as modulations strategies of MC based on related publications. Keywords: matrix converter, review, bidirectional switch commutation, modulation, space vector modulation. INTRODUCTION The term “Matrix Converter” is initially stated by Venturini back in 1980 [1]. A Matrix Converter (MC) allows forward and reverse capability via an array of four quadrant, fully controllable bidirectional switches. A common three-phase to three-phase MC (3 × 3 MC) is capable of performing direct AC to AC voltage conversion without requiring any DC conversion in the process. This attribute promotes MC as an appealing alternative to the inverter. Conventional inverter involves a two-stage power conversion. Input AC voltage is firstly rectified to DC voltage before inverted to desired output AC load voltage through a PWM inverter [2]. Unlike the inverter where conversion of AC to DC voltage is necessary, requirement for any smoothing electrolytic DC link capacitor is clearly absent in MC topology. Figure-1. A comparison between inverter and MC in AC to AC conversion stage. While providing high input power with unrestricted frequency operation, MC contributes to reduced input current harmonics, more compact in size and higher efficiency in comparison to the inverter. An MC also perform AC to DC, DC to AC or even DC to DC conversion with the very same topology, depends on what type of source and load the MC is implying, either AC or DC [3]. Input and output connection phases of an MC are also arbitrary and not solely restricted to three-phase to three-phase connection. MC evolved from Forced Commutated Cycloconverters (FCCC) [4]. Besides the FCCC, Naturally Commutated Cycloconverters (NCCC) is also a type of cycloconverters. The NCCC rely on discontinuous control- type switches like thyristors which turns off only when voltage difference between the outgoing and incoming switches is in correct polarity. In contrary to the NCCC, the FCCC switches use active-control switches like power transistors. Its switching can be actively turned off in any desired instance. The earlier version of the FCCC utilises thyristors similar with NCCC but with an additional external commutation circuit to realize bidirectional switches function. Table-1 below summarises the cycloconverters type. Table-1. Types of cycloconverters based on its switching device type and output frequency. MATRIX CONVERTER TYPES MC is classified into conventional or Direct MC (DMC) and Indirect MC (IMC) [4]. The name given to each category is an indication of how the MC operates; either through direct or indirect means. The ‘direct’ operation was initiated by Venturini and Alesina with their “low frequency modulation matrix” mathematical modelling [5]. The designated modulation is directly multiplied with input voltage to obtain required output voltage, hence the “direct transfer function” term.