Development of the equipment for gearless gas-turbine power plants

Abstract

There has been a new trend in construction of gas-turbine power plants with power output of hundreds and thousands of kilowatts. An expensive gearbox and a bulky generator with a rotational speed of 1500–3000 rpm are excluded from the power plant. A gas-turbine engine rotates the generator directly without the gearbox. The rotational speeds of the gas turbine and the generator are equal. The generator produces a high-frequency voltage, which is converted into the 50-Hz voltage via a semiconductor converter. This solution simplifies the structure of the power plant, enhances its reliability, and decreases costs. Currently, in such power plants, permanent-magnet generators are used that are sensitive to overcurrents and overheating and require expensive rare-earth magnets. The problem of ensuring mechanical strength of the permanent-magnet rotor at high rotational speeds is also essential. We propose to use synchronous reluctance generators that are free of the above drawbacks. The generators are controlled by frequency converters according to a special algorithm. The results of testing a model of the system with a synchronous reluctance generator are presented in the article. Variants of electrical equipment of the power plant based on synchronous reluctance generators are considered. The possibility of creating high-speed, up to 30000 rpm, synchronous reluctance generators for the gas-turbine power plants is shown.