Proposal for Universal Direct Converter Based on Matrix Converter for Three-phase AC and DC Source

Abstract

Recently, power converters have been used in various electric machines, electric devices, etc. However, depending on the power sources, it is necessary to change the circuit topology to DC/AC, AC/DC, or AC/AC. In some applications such as the AC and DC dual locomotive, the power converter should be applicable for both AC and DC sources. For the applications, a converter that combines AC/DC and DC/AC is conventionally used. On the other hand, this paper presents a direct converter that is applicable for any source, utilizing the topological common point between the three-level inverter and the matrix converter and developing a modulation method. By using the modulation method and the matrix converter (MC) circuit, it is possible to achieve either DC/three-phase AC or three-phase AC/three-phase AC power conversion with a common duty calculation scheme. In addition, the proposed system allows two features. First, a control of the neutral point fluctuation, and second, dead time compensation is not required because current commutation can be applied for the three-level DC/AC. The numerical simulations and experiments have validated the conversion and enabled the authors to propose a new concept for a power conversion system.