Abstract
This paper describes the operation of a solid-state generator proposed to produce high-frequency bipolar high-voltage pulse bursts on resistive-type loads, intended for medical applications. The generator design is based on two independent solid-state unipolar positive Marx generators positioned back to back, where the load is placed between the outputs of the two generators. SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) are used in order to allow high-frequency operation. A generator with two five-stage Marx generators is experimentally tested in order to deliver up to 5000-V/50-A bipolar pulses, with 500-ns–10- $\mu \text{s}$ pulse widths and 200-ns–10- $\mu \text{s}$ relaxation time between positive and negative pulses. The generator operates in the burst mode from 1 to 200 pulses, in excess of 500 kHz within the burst, which can have a repetition frequency up to 1 kHz limited by the input 1000-V/200-W power supply, with forced air cooling. Results, with resistive-type loads, for several single pulse and burst mode operations are presented and discussed.
Highlights
H IGH-FREQUENCY burst of bipolar microsecond-range high-voltage pulses has been recently explored to be an effective new technique associated with the traditional irreversible electroporation therapy, which mitigates muscle contraction, for example, in the nonthermal ablation of tumors [1]–[4].Compared with a typical unipolar pulse, shown in Fig. 1(a), 2 to 400 bipolar pulse bursts, of 0.5–2.0-μs width, and several kilovolt amplitudes can be used, as shown in Fig. 1(b), with a relaxation time, tr, up to 5 μs
This paper presents the design and experimental results of a solid-state bipolar Marx generator developed for biomedical applications, based on the connection of two positive Marx generators back to back, producing up to 5-kV bipolar high-voltage pulses, with waveform characteristics similar to the one shown in Fig. 1, for currents up to 50 A and a frequency in excess of 500 KHz during a burst
The bipolar solid-state Marx generator is based on the unipolar positive Marx shown in Fig. 2, with n stages, and each stage comprising a diode, Di, an energy-storing capacitor, Ci and two switches, Sci and Spi, in this case, metal–oxide– semiconductor field-effect transistors (MOSFETs), for i ∈ {1, ..., n} [14]
Summary
H IGH-FREQUENCY burst of bipolar microsecond-range high-voltage pulses has been recently explored to be an effective new technique associated with the traditional irreversible electroporation therapy, which mitigates muscle contraction, for example, in the nonthermal ablation of tumors [1]–[4]. Marx-type generators are often used for producing bipolar high-voltage pulses, from pure Marx circuits [9], or in combination with the transformer [10] and with H-bridges [11]. This concept has been shown for spark-gap Marx circuits [13], it has never been used with solid-state based Marx generators and for high-frequency burst applications. This paper presents the design and experimental results of a solid-state bipolar Marx generator developed for biomedical applications, based on the connection of two positive Marx generators back to back, producing up to 5-kV bipolar high-voltage pulses, with waveform characteristics similar to the one shown, for currents up to 50 A and a frequency in excess of 500 KHz during a burst This paper presents the design and experimental results of a solid-state bipolar Marx generator developed for biomedical applications, based on the connection of two positive Marx generators back to back, producing up to 5-kV bipolar high-voltage pulses, with waveform characteristics similar to the one shown in Fig. 1, for currents up to 50 A and a frequency in excess of 500 KHz during a burst
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