A power supply for one-second source of highly-stable magnetic field

Generation of high-power microwave (HPM) pulses at high pulse rates requires strong magnetic fields, which are commonly produced in superconductive cryomagnets. Batch operation of HPM sources allows the use of quasi-stable magnetic field produced in a solenoid powered from a bank of capacitors. Modern capacitors (such as molecular ones) possess energy storing density /spl sim/3.8 J/cm/sup 3/. This paper presents a fully controlled power source for a one-second solenoid. The energy store consists of 32 molecular capacitors connected in series in four stages. The total capacity of the store is 9.2 F, the output voltage is 600 V, and the stored energy is 1.6 MJ. The capacitive store is charged from four independent 20-Ampere DC sources. The charging takes less than 5 min. To produce the magnetic field, the solenoid is switched onto the capacitive store via switching current regulator assembled from isolated-gate bipolar transistors (IGBTs). Controlling the transistor switch with PWM-controller allows a decrease in the solenoid current less than 5% while the voltage across the capacitive store drops from 600 to 300 V. The solenoid maximum current is 1.2 kA.