High switching frequency amplifier of IGBT for disruption feedback control systems

High-power, high-switching-frequency amplifiers have been developed for stabilizing the m=2/n=1 MHD (magnetohydrodynamic) mode of plasma in the JFT-2M to avoid plasma disruptions. The amplifiers are a set of two inverters (INV 1 and INV 2). Each inverter has a current of 1500 A, a voltage of 500 V, and a switching frequency of 20 kHz. The component device of the inverter is an IGBT (insulated gate bipolar transistor) MG300N1US1. Each inverter has three bridges composed of eight IGBTs with eight high-speed free-wheeling diodes, respectively. Controllers of the inverters are made by the PWM (pulse width modulation) method and directly operated by voltage references E/sub c/. In the test operations, each inverter operated in the switching frequency of 20 kHz, and the maximum sine-wave current of +1500 A--1500 A at the 60-Hz reference signals.<
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