Development of Current-Source-Inverter-based Integrated Motor Drives using Wide-Bandgap Power Switches

Abstract

The miniaturization of power electronics is made possible by using wide-bandgap (WBG) power switches that can operate at high switching frequencies and high temperatures. Thus, WBG devices open the door for promising opportunities for the development of integrated motor drives (IMDs) that places the power electronics and the electric machine in the same enclosure. The concept of IMDs can replace traditional adjustable speed drives consisting of motor and inverter connected by a cable. However, WBG-based IMDs still faces many challenges regarding electromagnetic interference, cooling, reliability, and packaging. Nowadays, the majority of IMDs use voltage-source-based inverters since this topology is naturally compatible with conventional silicon-based power devices. Nevertheless, major advances in the development of new types of power semiconductor switches made from WBG semiconductor materials such as gallium nitride create new competitive alternatives for the development of reverse-voltage blocking (RVB) switches that are well-suited for use in current-source inverters (CSIs). This paper investigates the use of WBG power devices in CSIs for use in IMD applications. A 3-kW concept demonstrator CSI is successfully built and tested exciting an RL load that emulates a surface permanent-magnet (PM) synchronous motor. This CSI-IMD achieves appealing efficiency values >97.6% at both half- and full-load conditions with a PWM switching frequency of 125 kHz and an inverter power density of 9.84 kW/L.