Performance Evaluation of Pulse Compressor-Based Modulators With Very Fast Rise Times for Plasma Channel Drilling

In this paper, limitations of compact and durable solid state modulators, using a 4.5-kV IGBT in combination with a pulse compression (PC) circuit are evaluated. Two investigated modulators uses two separate paths: one for ignition voltage and one for high currents. In the first modulator, ignition voltage is generated with a PC circuit based on saturable transformers, which is used to charge a series capacitor. After saturation, the capacitor is connected to the output. The second modulator combines together pulse transformer and magnetic switch. Parasitics have been estimated to find the optimal modulator configuration. Measurement results for validating the models as well as the simulation results are presented. Main limitation factors are described and possible solutions are discussed.