The breakdown voltage characteristics and the secondary electron production in direct current hydrogen discharges for the gaps ranging from 1 μm to 100 μm

A novel 4H-SiC MESFET was presented, and its direct current (DC), alternating current (AC) characteristics and power added efficiency (PAE) were studied. The novel structure improves the saturation current (Idsat) and transconductance (gm) by adding a heavily doped region, reduces the gate-source capacitance (Cgs) by adding a lightly doped region and improves the breakdown voltage (Vb) by embedding an insulated region (Si3N4). Compared to the double-recessed (DR) structure, the saturation current, the transconductance, the breakdown voltage, the maximum oscillation frequency (fmax), the maximum power added efficiency and the maximum theoretical output power density (Pmax) of the novel structure is increased by 24%, 21%, 9%, 11%, 14% and 34%, respectively. Therefore, the novel structure has excellent performance and has a broader application prospect than the double recessed structure.

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Ionization and Secondary Electron Production by Fast Charged Particles

Charged Particle and Photon Interactions with Matter ◽

10.1201/9780203913284.ch3 ◽

2003 ◽

Author(s):

Larry Toburen

Keyword(s):

Secondary Electron ◽

Charged Particles ◽

Electron Production

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Thermal breakdown in high voltage direct current cable insulations due to space charges

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-12-2017-0531 ◽

2018 ◽

Vol 37 (5) ◽

pp. 1689-1697 ◽

Cited By ~ 2

Author(s):

Christoph Jörgens ◽

Markus Clemens

Keyword(s):

Electric Field ◽

Breakdown Voltage ◽

High Voltage ◽

Direct Current ◽

Aging Effect ◽

Radial Symmetry ◽

Thermal Breakdown ◽

Content Type ◽

High Voltage Direct Current ◽

Space Charges

Purpose In high voltage direct current (HVDC), power cables heat is generated inside the conductor and the insulation during operation. A higher amount of the generated heat in comparison to the dissipated one, results in a possible thermal breakdown. The accumulation of space charges inside the insulation results in an electric field that contributes to the geometric electric field, which comes from the applied voltage. The total electric field decreases in the vicinity of the conductor, while it increases near the sheath, causing a possible change of the breakdown voltage. Design/methodology/approach Here, the thermal breakdown is studied, also incorporating the presence of space charges. For a developed electro-thermal HVDC cable model, at different temperatures, the breakdown voltage is computed through numerical simulations. Findings The simulation results show a dependence of the breakdown voltage on the temperature at the location of the sheath. The results also show only limited influence of the space charges on the breakdown voltage. Research limitations/implications The study is restricted to one-dimensional problems, using radial symmetry of the cable, and does not include any aging or long-term effect of space charges. Such aging effect can locally increase the electric field, resulting in a reduced breakdown voltage. Originality/value A comparison of the breakdown voltage with and without space charges is novel. The chosen approach allows for the first time to assess the influence of space charges and field inversion on the thermal breakdown.

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