Overvoltage Discharge Research Articles

Minimizing Voltage Ripple of a DC Microgrid via a Particle-Swarm-Optimization-Based Fuzzy Controller

DC microgrids play a crucial role in both industrial and residential applications. This study focuses on minimizing output voltage ripple in a DC microgrid, including power supply resources, a stochastic load, a ballast load, and a stabilizer. The solar cell serves as the power supply, and the stochastic load represents customer demand, whereas the ballast load includes a load to safeguard the boost circuits against the overvoltage in no-load periods. The stabilizer integrates components such as electrical vehicle batteries for energy storage and controlling long-time ripples, supercapacitors for controlling transient ripples, and an over-voltage discharge mechanism to prevent overcharging in the storage. To optimize the charging and discharging for batteries and supercapacitors, a multi-objective cost function is defined, consisting of two parts—one for ripple minimization and the other for reducing battery usage. The battery charge and discharge are considered in the objective function to limit its usage during transient periods, providing a mechanism to rely on the supercapacitor and protect the battery. Particle swarm optimization is employed to fine-tune the fuzzy membership function. Various operational scenarios are designed to showcase the DC microgrid’s functionality under different conditions, including scenarios where production exceeds and falls below consumption. The study demonstrates the improved performance and efficiency achieved by integrating a PSO-based fuzzy controller to minimize voltage ripple in a DC microgrid and reduce battery wear. Results indicate a 42% enhancement in the integral of absolute error of battery current with our proposed PSO-based fuzzy controller compared to a conventional fuzzy controller and a 78% improvement compared to a PI controller. This translates to a respective reduction in battery activity by 42% and 78%.

Characteristics of the Nanosecond Overvoltage Discharge Between CuInSe2 Chalcopyrite Electrodes in Oxygen-Free Gas Media

The characteristics of the nanosecond overvoltage discharge ignited between semiconductor electrodes based on the CuInSe2 chalcopyrite compound in the argon and nitrogen atmospheres at gas pressures of 5.3–101 kPa are reported. Due to the electrode sputtering, chalcopyrite vapor enters the discharge plasma, so that some CuInSe2 molecules become destroyed, whereas the others become partially deposited in the form of thin films on solid dielectric substrates located near the plasma electrode system. The main products of the chalcopyrite molecule decomposition in the nanosecond overvoltage discharge are determined; these are atoms and singly charged ions of copper and indium in the excited and ionized states. Spectral lines emitted by copper and indium atoms and ions are proposed, which can be used to control the deposition of thin chalcopyrite films in the real-time mode. By numerically solving the Boltzmann kinetic equation for the electron energy distribution function, the electron temperature and density in the discharge, the specific losses of a discharge power for the main electronic processes, and the rate constants of electronic processes, as well as their dependences on the parameter E/N, are calculated for the plasma of vapor-gas mixtures on the basis of nitrogen and chalcopyrite. Thin chalcopyrite films that effectively absorb light in a wide spectral interval (200–800 nm) are synthesized on quartz substrates, by using the gas-discharge method, which opens new prospects for their application in photovoltaic devices.

Parameters of Nanosecond Overvoltage Discharge Plasma in a Narrow Air Gap between the Electrodes Containing Electrode Material Vapor

Parameters of the nanosecond overvoltage discharge plasma in an air gap of (1÷5) × 10−3 m between the electrodes, which contains the vapor of an electrode material (Zn, Cu, Fe) injected into plasma due to the ectonic mechanism, have been studied. The dependences of those parameters on the ratio E/N between the electric field strength E and the particle concentration N in the discharge are calculated for the “air–copper vapor” system, by using the numerical simulation method.

Investigation of the synthesis of nanoparticles by pulsed electrical erosion in the conditions of overvoltage of the discharge gap

The process of obtaining silver nanoparticles by the method of electro erosion of metal electrodes when over-voltage discharge gap therebetween. For this purpose, a new scheme of an electric pulse erosion unit is proposed and investigated. Experimental results show the possibility of obtaining nanoparticles of conductive materials with a narrow size distribution by this method.

On the Mechanism of Maintenance and Instability of the Overvoltage Low-Pressure Discharge Forming a High-Current Runaway Electron Beam

Results of experiments on the study of dynamics of an overvoltage discharge at the low pressure р = 0.5–2.5 Torr up to its transition to the high-current low-voltage regime are presented, and the instability mechanism leading to a sharp voltage drop across the discharge is suggested.

Difference in shape and width of Dα lines in the overvoltage and abnormal glow regimes of open discharge in narrow gap

Strong overvoltage discharges in a narrow gap between the solid cathode and grid anode (so called “open discharges”) are widely used for generation of the high-current electron beams. At low gas pressure (about 1 Torr) we revealed that discharge in the overvoltage gap stressed by stepwise voltage with amplitude up to 25 kV exhibits two regimes which follow one by one and generate the e-beams. The first of them produces the high-energy e-beam but the second generates the low-energy e-beam. The physical properties of these gas discharge regimes have been explored insufficiently. We have done the spectroscopic measurements of these regimes in D2 and found out that the overvoltage regime produces positive ions with high kinetic energy up to several keV but anomalous glow discharge forms the ions with energy of several tens of eV. The existence of high-energy ions in the overvoltage discharge provides a strong increase in the electron secondary emission from the cathode and possibly contributes to the ionization of the gas by fast ions. Our findings promote more insight into physics of the overvoltage discharge generating the high-current e-beams with energy up to 25 keV.

Stepping Development of 6-m Long-Gap Discharge Produced by Standard Switching Impulse

A switching overvoltage discharge experiment was conducted on a simulated tower head. The gap spacings among the six-multiple conductor, the cross arm, and the tower were 6.07 m, respectively. The discharge development driven by a 250/2500-μs standard switching impulse was captured by a high-speed camera. The images show that the discharge path presents a stepping mode, and only one streamer guides the leader development. The discharge forms a snake-like route. Each segment of the stepping development is with a length of 1-3.5 m, and the observed curve angle ranges from 40° to 60°.