Introduction of a large scale high efficiency 5-level IEGT inverter for oil and Gas industry

In the Oil and Gas Industry, there is a trend towards all electrically-driven compressor power train equipment, instead of gas turbine operated equipment; and simultaneously higher system availability is required with smaller installation space, considering environmental issues for the compressor driven equipment. In general, tens of MW capacity compressors are used in the LNG plant, so the electrically-driven power train AC motor and drive equipment must have large capacity and capability for high speed operation. In this study, we will introduce our development of a 5-level IEGT (Injection Enhanced Gate Transistor) inverter which is applicable in the Oil and Gas Industry as a high speed, large capacity power train with high efficiency, high reliability, and smooth output voltage waveform. One unit of this inverter has a capacity of 20MVA, so by connecting four units in parallel it is possible to obtain 80MVA rating. This paper also reports the results of a full power inverter and motor combined test which illustrates the principles and mechanisms of a 5-level inverter system.