Mitsubishi Heavy Industries Technical Review
    Vol. 55 No. 4 (2018)   New Power Domain Projects
    New Products

    Compact Variable Speed Drive System for Compressor Driver with Low CAPEX and Low OPEX which born under New Idea

    Mitsubishi Heavy Industries
    Compressor Corporation

    In recent years, there have been moves toward motorization in many fields to facilitate operation and reduce maintenance costs. In the industrial equipment field, the number of cases where electric motors are adopted for drivers has increased. Motors have conventionally been operated at a constant frequency of 50Hz or 60Hz. Along with the increase in the capacity of frequency converters (inverters), motors have been used as large-capacity and variable-speed drivers with the frequency being changed. With such a background, the number of electric variable speed drivers used in large-capacity compressors has been increasing. On the other hand, the number of large-capacity electric variable speed drivers used is yet few, and the number of manufacturers of transformers and inverters requiring such a special capacity are limited. Therefore, the customer's equipment purchase cost increases, and the operating cost also increases due to the power loss of the transformer and inverter. These increased costs are the negative factors in introducing them. In order to solve the aforementioned issues, a new idea was produced where the main power of a compressor is supplied by a large capacity constant speed motor and the power contributing to the variable speed is supplied by a small-capacity variable speed driver. Under this new idea, a low-cost and high-efficiency variable speed driver for compressor drivers, the IMG-VSDS (Integrated Motor Gear - Variable Speed Drive System), was developed, in which two powers are integrated at the speed-increasing gear. A 6MW prototype device was manufactured, and various tests such as overload and severe tests were conducted and the IMG-VSDS was produced. This report introduces the IMG-VSDS product.