Pseudospark switch (PSS) is a high voltage and high current switching device operating in the low-pressure discharge regime with unique hollow cathode-anode electrode geometry. In this paper, the switching characterization with hydrogen gas at different loads (R L = 8.3 Ω & 2.7 Ω) have been presented for the multi-gap multi-aperture pseudospark switch (MGMA-PSS) for fast pulse power applications. Simulation analysis has been carried out to understand the role of the multi-aperture geometry for the different aperture sizes (2.4 mm & 3 mm). Switching characterization of the MGMA-PSS has been carried out at different operating conditions. The switching performance is observed with and without saturable inductor (SI). The SI is used to improve the switching behavior by reducing the commutation losses during the discharge process. Further, circuit analysis is also studied for the multi-gap arrangement of the discharge. This study would be very much useful for the optimization of the discharge characteristics for the design and development of high-power multi-aperture PSS for fast pulse power applications.
In the present research work simulation and experimental investigations have been carried out for discharge characterization of single to multi-gap pseudospark discharge-based plasma cathode electron (PD-PCE) source for the generation of high-density and energetic pulsed electron beam. The developed PD-PCE source has been operated with different gases (Ar, N2, He), applied voltages (5-35 kV), and electrode aperture sizes (2-6 mm). The proposed analysis has helped for the design and development of multi-gap (4-gap) PD-PCE sources having uniform sequence of electrode apertures (SEA) diameters (2 -4 mm) for pulsed electron beam generation. The pre-breakdown, hollow cathode and conductive phases have been analyzed and found their dependency on the operating and circuit parameters. The generation of high density $(\sim 3.0\times 10^{5} {\mathrm {A}}/{\mathrm {cm}}^{2}$) and up to 32 kV pulsed electron beams are governed by the penetrated dynamic equipotential lines in the 4-gap PD-PCE source having uniform electrodes aperture diameter of 2 mm. In addition, it also facilitates the generation of the high pulsed electron beam current of $\sim 1.5$ kA with the current density of $\sim 1.0 {\mathrm {x}} 10^{4} {\mathrm {A}}/{\mathrm {cm}}^{2}$ at $\sim 35$ kV applied voltage with the 4 mm electrode aperture. These studies would be very much beneficial for the generation of short pulsed electron beams for EUV/soft X-ray radiation and surface modification of materials.
Electromagnetic repulsive forming technology is a high-strain rate forming technology used for shaping of components made of metallic sheet, tube forming, joining operations, explosive welding, etc. A current pulse is passed through the tooling coil, generating a high-intensity magnetic field, which interacts with the induced currents in the electrically conductive workpiece, resulting in significant plastic deformation. The generated magnetic pressure, in this case, pushes the workpiece away from the coil. Electromagnetic attractive forming technology is another method to produce an attractive force on the workpiece using induced currents. However, this requires specialized pulsed power circuits and tooling systems to achieve the final objectives. This paper presents the design of a novel uniform pressure universal tooling coil that can be used for both repulsive and attractive forming of the workpiece without changing the pulsed power source and the tooling coil configurations. The designed tooling coil provides flexibility of operation, and the forming modes can be easily switched as per the process requirements. The paper focuses on the electromagnetic design of the tooling coil, and the performance of the tooling coil has been simulated in both configurations. The operating principle has been described in detail, and the results have been discussed in both the forming modes.
A Vector Inversion Generator (VIG) takes electrostatically stored energy and converts it into a fast-rising high-voltage pulse. VIGs have been created by winding a double layer of conductive foil and dielectric material on a cylindrical mandrel creating a spiral wound device. The author has built and tested a VIG in a novel geometry that exhibits the same Vector Inversion Generator principle as a spiral wound device. The proof of principle testing results of the novel geometry VIG are compared to those of a spiral wound VIG of approximately the same single-line conductor area, number of windings, and equivalent diameter. The comparison shows that the novel geometry VIG creates nearly the same output fast-rising high-voltage pulse as the spiral wound VIG and with the same level of efficiency. The novel geometry VIG shows promise for enabling the creation of VIG pulse generators in a more compact geometry with a lower overall device weight than the equivalent spiral wound VIG.
We are reporting on a capacitor charger with a rated peak voltage of 50kV. The charger is fed from a standard 208V, 3-phase AC utility outlet. The HV package, consisting of a high frequency transformer, HV rectifier and HV feedback voltage divider was provided by Stangenes Industries and is contained in a 19 inch, 5U rack mountable package. The primary of the transformer is driven by an H-bridge inverter. Inverter current control is achieved through a Digital Signal Controller (DSC) with a fast PWM controller and a programmable analog comparator. The DSC provides cycle-by-cycle peak current mode control as well as current loop stabilization through digital slope compensation. The charger is controlled by an Industrial controller with a touch screen interface. The touch screen interface involves multiple programmable and customizable screens. The controller monitors the output voltage of the load capacitor and closes the voltage loop. A back-up safety function limits the charge time should the voltage loop be broken or not work properly.
