Design of the Double-Fed Unit for J-TEXT 100 MVA Pulse Generator System

Abstract

J-TEXT, formerly known as TEXT-U, has been reconstructed since 2004. The 100 MVA pulse generator system is the main power supply of J-TEXT, including the toroidal coil, the ohmic heat coil and the divertor coil and high-voltage power supply for Electron Cyclotron Resonance Heating. The pulse generator system was designed in USA with a 60 Hz grid so that the maximum rotation speed of the flywheel was 713 rpm and the maximum stored energy was 185 MJ. Now in China the grid is 50 Hz, in asynchronous mode the maximum rotation speed of the flywheel is 598 rpm and maximum stored energy is 128 MJ. To reach the designed maximum rotation speed of the pulse generator system, a doubled-fed unit is designed to ensure the tokamak operates with high parameters. This paper presents the design procedure of the double-fed unit: including the stator field oriented control of the double-fed induction motor, voltage oriented control of the AC–DC rectifier and the structure of the control system. The experiment results show the feasibility of the unit.