Study On The Characteristics Of All - Solid - State Pulse Source Under Capacitive Load

This paper analyzes the performances of the all-solid-state pulsed power modulator in the condition of being connected to capacitive loads, and a series of research work has been done on rectangular waveform, bipolar output, narrow pulses, and so on. A newly unipolar rectangular pulse adder is proposed, which has the ability of outputting high-voltage high repetition frequency rectangular pulses with capacitive loads; and another all-solid-state bipolar pulse adder is also developed, which is based on the improved phase-shift control method and capable of generating bipolar narrow high-voltage pulses. For the former one, the paper describes its operational principles and designs, while for the later one, more attention is paid to analyzing its control strategy.The operational principles and merits of conventional solid state Marx and pulse adder modulator is stated at the beginning of this paper. And then, the mechanism of long pulse tail problem is studied, and an important characteristic of the all-solid-state pulsed power source that can drive capacitive loads directly is concluded. Basing on that, the paper presents a newly topology and introduce chop state to obtain rectangular pulses even with capacitive loads. Related experimental results are given, too.In addition, to meet the requirements of bipolar or narrow pulses in many occasions, another pulse adder based on full-bridge inverter unit is presented. The stray capacitance existing in circuit has an important influence on both rising edge and falling edge, and pre-pulse and long tail are observed. Corresponding solutions are given, and a novel control method is prosed which make the designed modulator be capable of outputting bipolar narrow high-voltage pulses. The ability of self-protection is also be validated, which proves the feasibility of high-voltage arbitrary waveform generator.Two prototypes have been assembled respectively, and are tested and verified reliably. The unipolar rectangular pulse adder successfully operates at an output voltage of30kV and a repetitive frequency of20kHz. The rise and fall times are less than200ns, and a minimum pulse width of6μs was obtained. While the bipolar pulse adder operating atl kHz repetition rate gives5kV bipolar pulses, with40ns rise/fall time, and60ns pulse widths.