Design and characterization of a high-power induction module at megahertz repetition rate burst mode

The special design considerations for a unique high-power multiple-pulse induction module at megahertz repetition rate burst mode are presented and a prototype triple-pulse induction module has been constructed to verify the engineering feasibility of such a scheme. In the prototype module, three single pulses produced independently by three Marx-charged Blumlein pulse forming lines are isolated and merged by six high-voltage rectifier diodes. Experiments conducted with an iron-based metallic glass (1K101) test induction cell demonstrate that a train of three ∼250 kV pulses separated by 800 ns can be obtained in the induction gap of the cell without resetting the magnetic cores between pulses. A pulse with a rise time of 35 ns, ±1% flat top of 60 ns, and full-width at half-maximum of 120 ns was obtained when tested with a formal linear induction cell and finely tuned. It appears that nonlinear characterization of magnetic cores results in an increase in magnetization current and voltage drop pulse by pulse; the distortion of voltage waveform is not observed in the module if the voltage-seconds of the magnetic cores are sufficient. Because 1K101 metallic glass core has two times the equivalent flux swing of that of NiZn ferrite, metallic glass is advantageous for designing a compact multiple-pulse induction cell. The maximum amplitude of the voltage reversal is about 26% of that of the incident pulse when the cores are saturated.