Design and testing of a 45-MW 100-Hz quadruple-star synchronous motor for a Liquefied Natural Gas turbo-compressor drive

Over the last few decades, the production of Liquefied Natural Gas (LNG) has been pushing the development of electric drives with increasingly high power ratings, up to several tens of megawatts. A consolidated technology in this field entails dual-star 2-pole synchronous motors fed by Load-Commutated Inverters (LCI) with supply frequencies between 50 and 80 Hz. This paper presents a novel drive concept for very high-power and high-performance LNG applications based on a 45-MW 4-pole 100-Hz quadruple-star synchronous motor supplied by four PWM multi-level Voltage Source Inverters (VSI). The genesis, development and industrial implementation of this new design concept are outlined. System full-load drive testing results are presented to successfully validate the proposed solution.