Flexible IGBT modules for high voltage high power modulator applications

Summary form only given. Modern RF accelerators, plasma implanters, and certain microwave modulators require sustained high average and peak powers to drive an assortment of dynamic loads. North Star has developed a standard solid-state module using a minimum number of IGBTs and parallel pulse transformers to provide as much as 7.5 MW peak power at voltages as great as 125 kV. Submodules of this system require <1500 volts input from a DC prime power source. Sustained operation at the 60 kW level has been demonstrated with tests conducted at 180, 360, and 500 Hz without failure. The largest unit constructed is capable of 180 kW of continuous operation and has been tested into both resistive and fault loads. The development of fast fault detection and a mechanism to safely inhibit operation to allow recovery was a crucial element of this work. This attribute is essential for driving HV klystron type loads which are prone to tube arcs that are inevitable during conditioning and sustained operation. This type of power supply is approximately half as expensive as a conventional thyratron modulator with more pulse duration flexibility - limited only by volt-second capability of the step-up transformer. Delivered systems have produced pulses from 1 /spl mu/sec to 140 /spl mu/sec depending on the design and application. High peak powers are achieved by paralleling standard sub-modules. North Star has commercialized this flexible IGBT chassis and delivered units that power TWT modulators, magnetrons, klystrons, plasma implantation equipment, transformer pulsed reset circuits, and arc sources. The variety of applications and transient load tolerance exhibited by the design has established the versatility and robustness of the North Star solid-state HV modulator.