Small Voltage Drop Research Articles

A parameter design method of LC filter circuit for closed‐loop dynamic power supply system based on linear power amplifier

AbstractThe linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged.

Fabrication and characterization of supercapacitor comprising mango kernel derived electrode under different electrolyte system

AbstractIn this work, supercapacitor or ultra‐capacitor cells are composed of active carbon material (ACM) having BET specific surface area of 1133 m2 g−1. The ACM is prepared by carbonizing waste biomass (mango kernel) at 900°C. To develop high porosity in ACM, potassium hydroxide was used as an activating agent. Porous morphology of the synthesized ACM is explored through Scanning Electron Microcopy. Thereafter, two supercapacitor cells have been composed by using the mentioned ACM (electrode material) and KOH 6 M & NaOH 1 M (electrolytes). Applicability of the electrode material for supercapacitor has been tested electrochemically through the standard CV, EIS, and CD techniques. Observed capacitive assets from CV curve at 5 mV s−1was 151.5 F g−1(with KOH 6 M) and 133 F g−1(with NaOH 1 M). Experimentally obtained impedance data from EIS technique were compared and fitted theoretically by utilizing Randles fitting circuit. By taking frequency into consideration, it is found that the KOH 6 M based cell is providing lower time constant value and supporting better diffusion process than NaOH. Analysis of CD curve at 1.1 A g−1have given the capacitance of 136.5 F g−1and corresponding energy and power density of 12.1 Wh kg−1and 930 W kg−1. In addition to this, the small voltage drop and low ohmic resistance observed with KOH based system suggests its better capacitive assets than NaOH based supercapacitor system. Moreover, good capacitance retention of 85% is observed in a 2000 life cycle test.

Cold start cycling durability of fuel cell stacks for commercial automotive applications

System durability is crucial for the successful commercialization of polymer electrolyte fuel cells (PEFCs) in fuel cell electric vehicles (FCEVs). Besides conventional electrochemical cycling durability during long-term operation, the effect of operation in cold climates must also be considered. Ice formation during start up in sub-zero conditions may result in damage to the electrocatalyst layer and the polymer electrolyte membrane (PEM). Here, we conduct accelerated cold start cycling tests on prototype fuel cell stacks intended for incorporation into commercial FCEVs. The effect of this on the stack performance is evaluated, the resulting mechanical damage is investigated, and degradation mechanisms are proposed. Overall, only a small voltage drop is observed after the durability tests, only minor damage occurs in the electrocatalyst layer, and no increase in gas crossover is observed. This indicates that these prototype fuel cell stacks successfully meet the cold start durability targets for automotive applications in FCEVs.

Design and simulation of low dropout voltage regulator using 180nm technology

Low Dropout (LDO) Voltage Regulators are the linear regulators which drives upon a very small differential voltage. The main components of the Low dropout voltage regulators are Error amplifier, Pass device, voltage reference source and Voltage divider network. The low dropout voltage regulator uses a variable input to give a steady, constantly controlled, low-noise DC output voltage. This is a linear voltage regulator that includes a small voltage drop among the input as well as the output that works even when the output voltage is extremely close to the input voltage. The Error amplifier circuit which is one of the components in Low dropout voltage regulator is designed in the standard 180nm CMOS technology, with supply voltage of 1.6V, the gain of the error amplifier is 74db, Band-gap reference circuit is implemented to produce stable reference voltage which is independent of temperature variations. The bandgap reference voltage circuit gives the output voltage of 1.2V. The low dropout voltage regulator produces constant output voltage of 1.8V for the input voltage range 2.1V to 3.5V and it provides constant output voltage for load variations.

Heterostructured lithium-rich layered oxides core@ spinel- MgAl2O4 shell as high-performance cathode for lithium-ion batteries

Lithium-rich layered oxides (LLO) with ultra-high specific capacity are one of the most promising cathodes for the next-generation lithium-ion batteries. However, the irreversible release of lattice oxygen will cause LLO surface reconstruction and electrolyte decomposition, resulting in low initial coulombic efficiency (ICE), high interface resistance as well as severe voltage and capacity degradation. Herein, a facile and effective strategy is proposed to stabilize the cathode materials by coating the LLO with spinel MgAl2O4. It is found that the robust MgAl2O4 (MAO) decoration layer can not only alleviate the lattice mismatch to sustain the structure integrity, but also inhibit the side reactions with electrolyte during long-term cycles. Furthermore, density functional theory calculations show that the surface oxygen release energy barrier is increased with the surface decoration of MAO. Accordingly, the coated LLO-based hetero-structured cathode exhibits a higher ICE (80.14%) and lower interface resistance than that of LLO electrode. Moreover, a reversible capacity of 176.6 mAh g−1 (with a capacity retention as high as 78.1%) and small voltage drop of 0.27 V are achieved even after 200 cycles at 1 C. This work sheds new light on the facile preparation and modification of lithium-rich layered oxides-related cathode for high-energy density lithium-ion batteries.

Origin of the current saturation level of p-doped silicon field emitters

Using p-type semiconductors for field emitters is one simple way to realize an integrated current limiter to improve the lifetime of the cathode. In this work, the origin of the current saturation of p-type silicon emitters is investigated in detail. Single emitters are electrically characterized and compared to simulation results. With a simulation model considering a high surface generation rate and elevated tip temperature, a good agreement to the measured data is found. This observation is supported further by alteration of the surface experimentally. Electrical measurements after different treatments in hydrofluoric acid as well as heated and subsequent operation at room temperature are well explained by the influence of surface generation. Furthermore, it is shown that the field penetration leads to a small voltage drop and a strong geometry-dependent reduction of the field enhancement factor.

A new operational approach to minimize open unified power quality conditioner rating: OUPQC-VAmin

Distribution Network (DNs) are always face with low quality of voltage and current which their corresponding indices have to be improved by the network operator. Custom power devices (CPDs) are compensating these voltage and current deficiencies. Lately, in smart DNs which are equipped by communication infrastructure, open unified power quality conditioner (OUPQC) is attracted by DN area academics and distribution network utilities. Hence, OUPQC is being applied in DNs to improve V & I related indices take advantage of its series and shunt units (SEU and SHUs) performance, respectively. Effectiveness of OUPQC performance in voltage sag (VS) condition is affected by ratio of active/ reactive power injection of SEU. In OUPQCs which their SEU are equipped with storage system (SS), active power injection is also provided for compensation of VS. Operational approach of OUPQC which decides the amount of (re)active power injection in each VS magnitude, determines required rating of SEU and SHUs. In this paper, the amount of (re)active power injection is tuned in such way that minimize the SEU rating. Moreover, the proposed method takes advantage of charging the SS in healthy condition so as to makes the SEU capable of maximum compensation in VS condition. Therefore, in healthy condition, reactive power injection compensating the small voltage drop while active power injects into the SS to charge it. In this paper, first a precise modeling of OUPQC-VAmin is proposed. Then, its integration method in backward/forward sweep based load flow (BFSLF) is suggested. The suggested model is applied in two DNs: 69-bus IEEE and real Iranian 95-bus DN. Achieved outcomes confirm the effectiveness of OUPQC in steady state healthy condition and particularly in VS condition is intensely enhanced considering the minimization of SEU rating. The proposed method may be applied in design of the operational approach of OUPQC.

Enhanced electrochemical properties of potassium-doped lithium-rich oxide@carbon as cathode material for lithium-ion batteries

Lithium-rich layered oxides are believed to be the most competitive cathode materials for next-generation lithium-ion batteries (LIBs) due to their high specific capacity, but the poor cycle stability and voltage attenuation severely limit their commercial applications. In this paper, a simple method combining surface treatment via pyrolysis of polyvinyl alcohol (PVA) and potassium ions (K+) doping, is designed to improve the above defects of the cobalt-free Lithium-rich material Li1.2Mn0.6Ni0.2O2 (LMR). The insoluble surface byproduct Li2CO3 and amorphous carbon nanolayer derived from the pyrolysis process of PVA alleviate the corrosion of acidic species with a favorable conductivity, while a large radius of K+ can enlarge the space of the lithium (Li) layer to facilitate the diffusion of Li+, suppress voltage polarization, and synchronously restrain the transformation from a layered structure to a spinel-like structure. After modification, the LMR material exhibits a great initial discharge capacity of 266.0 mAh g−1 at 0.1C, a remarkable rate capability of 159.1 mAh g−1 at 5C and an extremely high capacity retention of 98.5% over 200 cycles at 0.5C with a small voltage drop.

Impacts of Lightning-Induced Overvoltage on a Hybrid Solar PV–Battery Energy Storage System

With increased electrical energy demands projected in the future, the development of a hybrid solar photovoltaic (PV)–battery energy storage system is considered a good option. However, since such systems are normally installed outdoors and in open areas, they are vulnerable to lightning strikes and may suffer from malfunctions or significant damage to sensitive components, which may result in a major breakdown and loss of revenue due to equipment replacement costs and inefficient operation. Thus, the objective of this paper is to investigate the effect of lightning-induced overvoltage on a hybrid solar PV–battery energy storage system, considering indirect lightning strikes nearby the system. The presented hybrid solar PV–battery energy storage system and lightning-induced overvoltage are modeled in Electro-Magnetic Transient Program-Restructured Version (EMTP-RV) software. The lightning-induced overvoltage is simulated based on a lightning waveshape of 10/350 µs using the Heidler expression, whilst the Rusck model is used to simulate the lightning-induced overvoltage. Different lightning current amplitudes (3, 19, and 169 kA), lightning strike locations (20, 50, and 100 m), and cable lengths (5, 10, and 20 m) are used to investigate the induced effects on the system and on the impulse withstand voltage of 6kV, as stated in MS IEC 60664-1 for solar PV–battery systems and inverters at the DC side. The results indicate that as the lightning strike distance increases from 20 to 100 m, the percentage of strikes exceeding the impulse withstand voltage reduces from 67% to 54% at 19 kA. At 169 kA, the impulse withstand voltage is exceeded by more than 100%, regardless of the strike distance (from 20 to 100 m). Furthermore, differences in cable length do not have much impact on the lightning-induced overvoltage due to the small voltage drop across the short cable length. This study provides useful information for PV systems owners and will be useful in assigning appropriate lightning protection schemes for PV farms.

Enabling large memory window and high reliability for FeFET memory by integrating AlON interfacial layer

A thin film of AlON with a nitrogen concentration of 13% was developed as the interfacial layer (IL) of HfZrOx-based ferroelectric field-effect transistor (FeFET) memory devices on a Si substrate. Compared to the conventional SiO2/SiON IL, due to a higher dielectric constant value that allows a smaller voltage drop across it and a larger valence band offset (ΔEv) with respect to Si along with prominent passivation of Si dangling bonds that effectively suppress hole trapping, memory devices with the AlON IL demonstrate a large memory window (MW) of 3.12 V by ±4 V gate voltage sweeping, robust endurance after 105 cycles with a long pulse width of 10−4 s, and a stable MW of 2.95 V up to 10 years, standing out from other HfZrOx-based FeFET memory reported in the literature. Furthermore, the AlON IL can be integrated with HfZrOx in the same atomic layer deposition step, which greatly simplifies the process. From the device performance and process integration points of view, the AlON IL unleashes the potential of FeFET memory by enabling high reliability with a large MW.

Maximizing Energy Storage of Flexible Aqueous Batteries through Decoupling Charge Carriers

AbstractFlexible aqueous rechargeable batteries that integrate excellent mechanical flexibility and reliable safety hold a great promise for next‐generation wearable electronics. Unfortunately, currently available options are unsatisfactory due to their low specific capacity, limited energy density, and unstable voltage output. Herein, to overcome these challenges, high theoretical specific capacity zinc and sulfur as the anode and cathode are selected, respectively. Furthermore, a strategy is proposed, that decoupling charge carriers in anolyte and catholyte to simultaneously endow the zinc anode and sulfur cathode with optimal redox chemistry, maximizes the energy storage of flexible aqueous batteries. The new zinc–sulfur hybrid battery possesses merits of ultrahigh theoretical specific capacity (3350 mAh gS−1) and volumetric energy density (3868 Wh L−1), low cost, ecofriendliness, and ease of fabrication and is a promising next‐generation aqueous energy storage system. The fabricated flexible aqueous zinc–sulfur hybrid battery delivers a stable output voltage (release 92% of its full capacity within a small voltage drop of 0.15 V) and an ultrahigh reversible capacity of 2063 mAh gS−1 at 100 mA gS−1, thus setting a new benchmark for flexible aqueous batteries and is promising to play a part in future flexible electronics.

Flexible self-supported bi-metal electrode as a highly stable carbon- and binder-free cathode for large-scale solid-state zinc-air batteries

Flexible (Ni, Co)3O4 nanosheets are grown on the surface of a Ni-foam by a facile electrodeposition coupled electrochemical oxidation process. The as-synthesized (Ni, Co)3O4 nanosheets are self-supported and can be directly used as the oxygen electrode without an addition of carbon or binder. As expect, the physical measurements and density functional theory (DFT) calculation reveal that Ni doping decreases Co3O4 surface activity towards the O, OH, OOH species, thus reducing the OER and ORR over-potentials. As a result, the (Ni, Co)3O4@Ni-foam electrode exhibits an unprecedented performance with a lower potential gap (⊗E: 0.57 V) than Pt/C+IrO2. This nanosheet can be readily applied as an electrode for Zn-air battery with a large area up to 24 cm2. The improved performance of this large-area electrode includes: a small charge-discharge voltage drop (0.56 V) and super stability with a high voltage efficiency of 69 % across all cycles.

Perancangan Perancangan Interkoneksi Pembangkit Listrik Tenaga Surya 1 MWp On-Grid Pada Jaringan Distribusi Cileungsi

Bogor is one of the major cities in Indonesia where electricity demand is increasing rapidly every year. PT Sinar Energi Indonesia has large vacant land plans to build a 1 MW Solar Power Plant (SPP) in the Cileungsi area. This is supported by the location which is close to the Cileungsi substation owned by PLN (800 meters) and also SPP is suitable with the characteristics of the electricity load in the area where the peak load occurs during the day and the development of SPP will reduce pollution caused by thermal plants. Interconnection of SPP with Cileungsi substation requires separate analysis to determine the best interconnection design between SPP and PLN grid. The author will use ETAP 12.6 software for load flow, short circuit and transient analysis so that the interconnection design will not cause harm, both for developers and for PLN. From the simulation results with ETAP 12.6 software does not show a negative impact (small power losses, small voltage drop, and the value of the short circuit current that occurs does not exceed the capacity of the equipment), and if there is a disturbance in the SPP unit, the transient shows within 1 second, the system has stabilized. Beside technical side, the economic point of view from this Solar Power Plant will also have a positive impact with the planned electricity tariff value of 6,884 cent US $ / kWh, still below the local production cost value (West Java 6.91 cent US $ / kWh, ESDM Ministerial Decree No.55 years 2019). Therefore, this research is expected to be able to help the developer and PLN in interconnection of the Solar Power Plant Cileungsi to PLN grid.

Developing the Guard Ring Topology of Power Silicon Diodes with a Blocking Voltage of up to 6.7 kV

High-voltage fast recovery diodes (FRDs) are characterized by a small forward voltage drop and low power dissipation. The main characteristics of such diodes is the reverse blocking voltage or the breakdown voltage. The aim of this work is to develop a guard ring topology allowing us to obtain the maximum possible blocking voltage of the diode and definite localization of the breakdown place under the conditions of the standard technological processes and without using new materials or substrates. The topology of the high-voltage part of silicon fast recovery power diodes is developed to obtain the maximum reverse blocking voltage. The calculations are carried out in the TCAD environment in the structure editor of which we included a program for the automatic creation of device models with dimensions of about several millimeters. The arrangement of guard rings is calculated according to the proposed principle allowing us to obtain power diodes with different breakdown voltages. The topology is developed so that the breakdown occurs under the edge of the active region, which guarantees the absence of catastrophic failures of the device. Power fast recovery diodes manufactured according to the proposed topology have the maximum reverse blocking voltage within the range of 3.3–6.7 kV, which indicates the reliability of the calculation methodology.

Controllable Hortensia-like MnO2 Synergized with Carbon Nanotubes as an Efficient Electrocatalyst for Long-Term Metal-Air Batteries.

The exploitation of a high-activity and low-cost bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as the cathode catalyst is a research priority in metal-air batteries. Herein, a novel bifunctional hybrid catalyst of hortensia-like MnO2 synergized with carbon nanotubes (CNTs) (MnO2/CNTs) is controllably synthesized by reasonably designing the crystal structure and morphology as well as electronic arrangement. On the basis of these strategies, the hybrid accelerates the reaction kinetics and avoids the change of structures. As expected, MnO2/CNTs exhibit a remarkable ORR and OER activity [low ORR Tafel slope: 71 mV dec-1, low OER Tafel slope: 67 mV dec-1, and small potential difference (Δ E): 0.85 V] and a long-term stability, which should be attributed to its unique morphology, K+ ions in the 2 × 2 tunnels, and synergistic effect between MnO2 and CNTs. Notably, in zinc-air batteries (ZABs), aluminum-air batteries (AABs), and magnesium-air batteries (MABs), the composite shows high power density (ZABs: 243 mW cm-2, AABs: 530 mW cm-2, and MABs: 614 mW cm-2) and large specific capacities (793 mA h gZn-1, 918 mA h gAl-1, and 878 mA h gMg-1). Importantly, the rechargeable ZABs reveal small charge-discharge voltage drop (0.81 V) and strong cycle durability (500 h), which are better than the noble-metal Pt/C + IrO2 mixture catalyst (the voltage drop: 1.15 V at first and 2 V after 100 h). These superior performances together with the simple synthetic method of the hybrid reveal great promise in large-power energy storage and conversion equipment.

Circuit nonlinearity effect on the performance of an electromagnetic energy harvester-structure system

Scavenging energy from structural vibration requires an efficient energy harvesting circuit which could introduce nonlinearity into the harvester-structure system. This study examines the performance of a linear structure equipped with an Electromagnetic (EM) energy harvester connected to a nonlinear standard energy harvesting circuit (SEHC) consisting of a full-wave bridge rectifier and a capacitor in parallel with a resistor. To facilitate the understanding of the nonlinear circuit effect on the behavior of the coupled harvester-structure system under sinusoidal excitation, a first-order harmonic balance approximation method is employed. Numerical simulation and experimental study are conducted to validate the accuracy of the proposed approximation method. Results suggest that the blockage effect of diodes in the bridge rectifier in the SEHC should be reduced by using diodes with small voltage drop value or by designing an EM energy harvester with large electromechanical coupling coefficient to improve the vibration mitigation performance and to enhance the optimal energy harvesting capability of the EM energy harvester. Results also show that circuit nonlinearity should be considered in order to estimate the response of the system accurately.

Load Current Decoupling Based LQ Control for Three-Phase Inverter

In classical inverter control, load current (disturbance) decoupling control is often used to improve the control performance. Yet, in a recent state-space control structure for multiresonant controllers, the load current decoupling technique is less studied. Moreover, in the classical control, the load current decoupling only has one control degree of freedom. Therefore, in this paper, a load current decoupling control combed linear quadratic (LQ) regulation is investigated, the proposed control structure that manipulates α and β axes as a unified system is adopted to increase the control degree of freedom. The LQ control synthesizes the state feedback control law including gains of the resonant controllers. Two general criteria, namely $H_{\infty }$ norm and zero dynamic, are proposed as the design guideline for the load current decoupling control. The effectiveness and robustness of the proposed approach are validated through MATLAB/Simulink simulations and experiments with a 5-kVA testbed. The results prove that some favorable performances, for example, the fast recovering time, the small voltage drop, and the low total harmonic distortion, are achieved by the proposed approach compared to the classical dual-loop proportional-resonant (PR) control with load current decoupling and the optimal $H_{\infty }$ control.

Optimization of PEM Fuel Cell Operation with High‐purity Hydrogen Produced by a Membrane Reactor

AbstractAn innovative micro‐cogeneration system (m‐CHP) based on membrane reformer and polymer electrolyte membrane fuel cell (PEMFC) is developed within the FluidCELL project. The purity of the hydrogen separated by the membrane reformer can decrease over time, due to membrane/sealing degradation, therefore a methanator is adopted to prevent CO poisoning of the fuel cell. This paper investigates the optimal control strategies of a polymer electrolyte membrane (PEM) fuel cell at different hydrogen purities by using a detailed 1D model, including the CO poisoning on the anode Pt‐Ru catalyst, and calibrated against experimental data. Simulation results show that the system is able to work also with low‐purity hydrogen thanks to the effectiveness of the methanator, the resistance to CO poisoning of the Pt‐Ru anode catalyst, the small voltage drop due to inert gases accumulation in the anode recirculation loop: at 0.3 A cm−2 as current density, the stack efficiency is always above 60% even when the membranes selectivity drops to 5 102.

Analytical and Experimental Evaluation of SiC-Inverter Nonlinearities for Traction Drives Used in Electric Vehicles

This paper investigates the inverter nonlinearities in a drive system based on silicon carbide metal-oxide-semiconductor field-effect transistor (SiC- mosfet s) and compares its performance with that of an equivalent silicon insulated-gate bipolar transistor (Si-IGBT) system. Initially, a novel comprehensive analytical model of the inverter voltage distortion is developed. Not only voltage drops, dead time, and output capacitance, but also switching delay times and voltage overshoot of the power devices are taken into account in the model. Such a model yields a more accurate prediction of the inverter's output voltage distortion, and is validated by experimentation. Due to inherent shortcomings of the commonly used double pulse test, the switching characteristics of both SiC- mosfet s and Si-IGBTs in the pulse width modulation inverter are tested instead, such that the actual performances of the SiC and Si devices in the motor drive system are examined. Then, the switching performance is incorporated into the physical model to quantify the distorted voltages of both the SiC-based and Si-based systems. The results show that, despite its existing nonlinearities, the SiC-based drive has lower voltage distortion compared to the conventional Si-based drive as a result of its shorter switching times and smaller voltage drop, as well as a higher efficiency. Finally, the overriding operational advantages of the SiC-based drive over its Si-based counterpart is fully demonstrated by comprehensive performance comparisons.

Hydrodynamic model of a dielectric-barrier discharge in pure chlorine

A one-dimensional hydrodynamic model of a dielectric-barrier discharge (DBD) in pure chlorine is developed, and the properties of the discharge are modeled. The discharge is excited in an 8-mm-long discharge gap between 2-mm-thick dielectric quartz layers covering metal electrodes. The DBD spatiotemporal characteristics at gas pressures of 15–100 Torr are modeled for the case in which a 100-kHz harmonic voltage with an amplitude of 8 kV is applied to the electrodes. The average power density deposited in the discharge over one voltage period is 2.5–5.8 W/cm3. It is shown that ions and electrons absorb about 95 and 5% of the discharge power, respectively. In this case, from 67 to 97% of the power absorbed by electrons is spent on the dissociation and ionization of Cl2 molecules. Two phases can be distinguished in the discharge dynamics: the active (multispike) phase, which follows the breakdown of the discharge gap, and the passive phase. The active phase is characterized by the presence of multiple current spikes, a relatively high current, small surface charge density on the dielectrics, and large voltage drop across the discharge gap. The passive phase (with no current spikes) is characterized by a low current, large surface charge density on the dielectrics, and small voltage drop across the discharge gap. The peak current density in the spikes at all pressures is about 4 mA/cm2. In the multispike phase, there are distinct space charge sheaths with thicknesses of 1.5–1.8 mm and a mean electron energy of 4.3–7 eV and the central region of quasineutral plasma with a weak electric field and a mean electron energy of 0.8–3 eV. The degree of ionization of chlorine molecules in the discharge is ~0.02% at a pressure of 15 Torr and ~0.01% at 100 Torr. The DBD plasma is electronegative due to the fast attachment of electrons to chlorine atoms: e + Cl2 → Cl + Cl–. The most abundant charged particles are Cl 2 + and Cl− ions, and the degree of ionization during current spikes in the active phase is (4.1–5.5) × 10–7. The mechanism of discharge sustainment is analyzed. The appearance of a series of current spikes in the active phase of the discharge is explained.