A comparison of indirect matrix converter based open-end winding drives against state-of-the-art

Abstract

Voltage source inverters (VSIs) are used in electric drives to generate a variable frequency, variable amplitude voltage for motor control. In addition to the desired three-phase output voltage, VSIs also generate high-frequency common-mode voltage that causes shaft voltage and stray currents; that in turn cause EMI and motor failure. VSIs also need a stable DC voltage input that is generated from a rectifier or an active frontend converter. In contrast matrix converter (MC) based open-end winding (OE Wdg.) drives offer direct AC/AC conversion, thus eliminating the large capacitor in the VSI based system's DC-link. When modulated exclusively using rotating vectors, the MC based OE Wdg. drives do not generate any common-mode voltage, thus eliminating a major cause of motor failure. The advantages offered by the MC based solution require more semiconductor switches but less reactive components. To choose between this solution and the state-of-the-art, the input/output waveform quality, passive component requirements, and the total losses of several different solutions are evaluated in this paper. Special attention has been paid to the output common-mode voltage related phenomenon since common-mode elimination is the primary motivation for employing modulation using rotating vectors and an open-end winding drive topology.