Development of super-synchronization speed control assembly for joint-texas experimental tokamak doubly-fed motor

Abstract

The main power of joint-texas experimental tokamak (J-TEXT) power supply is a 100MVA pulse generator unit, which is consisted of a 1417kW motor, a 75T flywheel and a 100MVA pulse generator. The generator unit was designed in USA, with a grid of 12kV/60Hz, but in China the grid is 10kV/50Hz. Due to the difference of grid frequency, the rotational speed can only reach 5/6 of the rated value, and the stored energy can only reach 70% of the rated value. To raise the speed from 598rpm to rated speed 713rpm, a new super-synchronization speed control assembly was developed. Under the MT coordinate system, a novel doubly-fed control strategy is designed to control the speed and rotor current of the motor. The converter regulate the rotor current by space vector pulse width modulation (SVPWM) control technology. The software system of double-fed control system is integrated into J-TEXT Control, Data Access and Communication (CODAC) system. The speed control system was fabricated, and put into operation, which can be successfully used to power the J-TEXT.