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Description
In order to study the influence of the rise/fall time of high-voltage nanosecond pulses on cell killing effect, a high-voltage nanosecond pulse generator with adjustable rise/fall time is needed. A novel generator topology based on half-bridge modular multilevel converter (HB-MMC) is proposed. Several HB-MMC submodules are connected in series as two arms to generate unipolar/bipolar high voltage nanosecond pulses. MOSFETs are used as v solid-state switches. By controlling the switching sequence of the MOSFETs, the rise/fall time of the pulse can be adjusted. In this paper, the proposed topology as well as its operating principle are introduced in detail and verified by PSpice simulation software. A 5-stage generator is implemented and tested. The test results show that the generator can output nanosecond pulses with adjustable amplitude of 0~±4 kV, pulse width of 100~500 ns and frequency of 0~5 kHz. The rise time of the pulse can be smoothly adjusted in the range of 15-65 ns, and the fall time of the pulse can be smoothly adjusted in the range of 30-100 ns.
