Papers by Keyword: Pulsed Power Supply

Abstract: Pulse switching characteristics of newly developed 3.3 kV SiC-MOSFET were investigated and they were provided for a prototype switching power supply (SPS). With supply voltage of 2.5 kV and the load resistor of 100 Ω, rise time T_r and fall time T_f were 76 ns and 88 ns respectively. The SPS exhibited a successful 2.5 kV-20 A-1 MHz burst mode operation.

Abstract: Amorphous boron carbide films were deposited with pulsed magnetron sputtering using a sintered B₄C target with Ar as the processing gas, and the chemical components, structure, and mechanical properties of the films were investigated. To deposit amorphous boron carbide films using a B₄C target, a pulsed power supply (14.4 kHz) was employed. Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were used to characterize the chemical compositions and structure of the films. According to the results of XPS, the B/C ratio in the films synthesized with pulsed magnetron sputtering was 2.21. Nanoindentation tests and ball-on-disk (BoD) tests were performed to evaluate the mechanical properties. It was found that the films deposited by pulsed magnetron sputtering had an average hardness of 32.1 GPa and an average Youngs modulus of 235.1 GPa.

Abstract: In the frame of shock-induced depoling, PZT 95/5 ferroelectric ceramics with niobium doped has been assembled for the pulsed power supply, and the electrical current output has been investigated under the action of shock wave in a "normal mode". The electrical response of LRC load especially for the small resistance (R) and small inductance (L) load was studied. Plane-shock-wave tests were conducted, and the PZT 95/5 ceramics stacked in parallel were devised to generate high-power electrical pulse. An output current of 7 kA has been obtained, and the corresponding rise time of the front edge is under 500 ns. Theoretical calculations were conducted and a good agreement with the experiment presented.

Abstract: Electrochemical machining (ECM) has been rarely applied in micromachining because the electric field is not localized. In order to explore the feasibility of applying ECM to micromachining at micro to meso-scale, an experimental setup with precision control over electrochemical micromachining (EMM) was developed, which is in fact a multifunctional machine tool. The micro tool electrodes for EMM can also be fabricated by micro electrical discharge machining (EDM) on the same machine tool. A high-frequency short-pulse micro-energy MOSFET power supply was designed. Lower machining voltage and lower concentration of passivity electrolyte are utilized together to localize dissolution area in EMM. A micro hole 45 ,m in diameter was drilled by EMM on stainless steel foil with 100 μm thickness. A new approach of fabricating microstructures by means of EMM milling using a simple micro tool electrode is proposed, and a shaped hole and a micro cantilever beam with high precision were acquired by EMM milling. The satisfactory process results indicate the potential capability of EMM for higher machining accuracy and smaller machining size.

Abstract: This paper presents an energy saving electrical discharge machining (EDM) pulsed power supply, the principle of which is introduced. This pulsed power supply possesses no current-limiting resistors used in conventional EDM pulsed power supplies and no energy storage inductors applied in most other energy saving pulsed power supplies. Direct current from DC power supply is chopped to form many branches of paralleling spike pulse currents and the current branches are then combined into the desired pulse current for EDM machining through cyclic superimposition. The calculation method of energy loss is then analyzed. The short-circuit and contrastive machining experiments proved that the new pulsed power supply was capable of performing stable machining with higher machining efficiency and less main-machining-circuit energy loss than those of conventional EDM pulsed power supplies.