Search

With the development of technology, low-temperature plasma plays an increasingly important role in industrial applications. The industrial application of low-temperature plasma has the following requirements for plasma, high electron energy, low macroscopic temperature, and uniformity. Low-temperature plasma driven by nanosecond pulses reflects more significant advantages in these aspects compared to direct current plasma and alternating current plasma. In this paper, a simple topology is proposed, which is based on the pseudospark switch and the diode opening switch. A pulse generator is developed, which can eventually output pulses with an amplitude of 106 kV, a rise time of 15.5 ns, a pulse width of 46 ns, and a maximum repetition rate of 1 kHz on a 260 Ω resistive load. The pulse generator can successfully drive needle-plate discharge plasma in ambient air. It has excellent parameters, stability, compactness, and a long lifetime. The proposed topology may be helpful for nanosecond pulse generators with amplitude ranging from tens to hundreds of kilovolts, which could be widely used in industry. [ABSTRACT FROM AUTHOR]

In recent years, several novel avalanche transistor-based power synthesis topologies have been proposed to improve the output performance of pulse generators based on avalanche transistors. The most promising is the topology based on avalanche transistors Marx Bank Circuits (MBCs) and linear transformer driver (LTD). However, it suffers from the same problems as other semiconductor switch-based LTD generators. The greater the number of LTD modules, the higher the requirements for synchronization and drive capability of the trigger system. This paper proposes a new self-triggering topology for pulse generators based on avalanche transistors MBCs and LTD, which significantly simplifies the entire generator's requirement for trigger system synchronization and driving capability. First, the circuit topology and its operation principle are introduced. Then, three prototypes with one trigger LTD module and three self-triggering LTD modules are developed. The output characteristics are experimentally investigated. The results verify the feasibility of the proposed topology. Finally, the output amplitude and the rise time are 3.35 kV/3.7 ns, 4.12 kV/3.7 ns, and 4.88 kV/4.0 ns on a 25 Ω resistive load, respectively. All generators can operate at 1 kHz. The topology proposed in the article maximally simplifies the requirements for synchronization and drive capability of the trigger system for generators based on avalanche transistor MBCs and LTD. [ABSTRACT FROM AUTHOR]

In this article, we show the feasibility of improving the performance of a high voltage and high repetition avalanche transistor pulse generator by applying a two-phase immersion cooling technique. The forced air cooling, single-phase immersion cooling, and two-phase immersion cooling techniques were applied to a 60-stage subnanosecond pulse generator. The experimental results indicate that the two-phase immersion cooling technique can effectively control the temperature rising of the avalanche transistor and, thus, reduce the time base jitter and voltage amplitude jitter. Five types of dielectric fluid with different boiling temperatures were comparatively studied. The FC-72 was finally adopted for the balanced performance on voltage amplitude and repetition rate. The two-phase immersion cooling technique could reduce the thermal resistance between the case and ambient and increase the maximum power from 330 to 876 mW. With this cooling method, the surface temperature of the transistor can be effectively controlled below 62 °C. The pulse generator could achieve outstanding performance with a voltage of 2350 V and a rise time of 180 ps. It can work stably at 200 kHz for more than 30 min, and the burst repetition rate could be 260 kHz within 1 min. This article offers new perspectives in the design of high repetitive avalanche transistorized subnanosecond generators. [ABSTRACT FROM AUTHOR]

Low-temperature plasma technology is widely used in various industrial fields, which require the plasma to be of large volume, diffuse, and stable. Furthermore, previous studies have shown that better plasma performance has been obtained by using generators with a high voltage, a high repetition rate, a fast rise time, and a short pulse duration. In this paper, a novel topology is proposed for such generators, which is based on magnetic switches and diode opening switches. A prototype is developed, and its output characteristics are investigated by varying essential parameters, such as the load resistance and the power supply voltage. The experimental results show that it can generate pulses with a voltage of 30.6 kV, a rise time of 7.1 ns, a pulse duration of 8.2 ns, and a maximum repetition rate of 12 kHz on a 300 Ω resistive load. The prototype has been successfully used to drive uniform plasma in ambient air. In the proposed topology, a diode is added to make the magnetic cores independent of each other, significantly simplifying the design calculation. It may help develop nanosecond solid-state generators. [ABSTRACT FROM AUTHOR]

In this paper, a 60-stage Marx circuit with the two-phase immersion cooling technique is presented. The performance parameters of the pulse generator with phase change immersion cooling and forced air cooling are compared. The results show that the maximum repetition rate is increased from 80 to 260 kHz, the pulse drift is significantly reduced from 900 to 200 ps, and the temperature rise of transistors is controlled effectively to enhance the stability of the amplitude. We also studied the influence of temperature on the turn-on and turn-off processes of the transistors to show the importance of heat management under high repetition conditions. Finally, a pulse generator is developed with the repetition rate of 200 kHz, the rise time of 180 ps, and the amplitude of 2350 V on a matched 50 Ω resistive load, which can work for more than 30 min. [ABSTRACT FROM AUTHOR]