Development of a 33 kV, 20 A long pulse converter modulator for high average power klystron

Abstract

Research, design, and development of high average power, long pulse modulators for the proposed Indian Spallation Neutron Source are underway at Raja Ramanna Centre for Advanced Technology. With this objective, a prototype of long pulse modulator capable of delivering 33 kV, 20 A at 5 Hz repetition rate has been designed and developed. Three Insulated Gate Bipolar Transistors (IGBT) based switching modules driving high frequency, high voltage transformers have been used to generate high voltage output. The IGBT based switching modules are shifted in phase by 120° with respect to each other. The switching frequency is 25 kHz. Pulses of 1.6 ms pulse width, 80 μs rise time, and 70 μs fall time have been achieved at the modulator output. A droop of ±0.6% is achieved using a simple segmented digital droop correction technique. The total fault energy transferred to the load during fault has been measured by conducting wire burn tests and is found to be within 3.5 J.

Optical fiber‐triggered solid‐state switch applied in power cables damped AC voltages test system

“…Conventional mechanical/air‐insulated breakers/switches are not suitable for this purpose because of the severe discharge that takes place during the switching process. A solid‐state switch based on semiconductors is an alternative option . However, the maximum voltage blocking capability of a single insulated gate bipolar transistor (IGBT) in commercial production is 6.5 kV .…”