High Voltage Power Research Articles

Integration of Superconducting Magnetic Energy Storage for Fast-Response Storage in a Hybrid Solar PV-Biogas with Pumped-Hydro Energy Storage Power Plant

Electric distribution systems face many issues, such as power outages, high power losses, voltage sags, and low voltage stability, which are caused by the intermittent nature of renewable power generation and the large changes in load demand. To deal with these issues, a distribution system has been designed using both short- and long-term energy storage systems such as superconducting magnetic energy storage (SMES) and pumped-hydro energy storage (PHES). The aim of this paper is to propose a metaheuristic-based optimization method to find the optimal size of a hybrid solar PV-biogas generator with SMES-PHES in the distribution system and conduct a financial analysis. This method is based on an efficient algorithm called the “enhanced whale optimization” algorithm (EWOA), along with the proposed objective functions and constraints of the system. The EWOA is employed to reduce the hybrid system’s life cycle cost (LCC) and improve its reliability, both of which serve as performance indicators for the distribution system. The proposed method for sizing a grid-connected hybrid solar PV-biogas generator with SMES-PHES is compared with other metaheuristic optimization techniques, including the African vulture optimization algorithm (AVOA), grey wolf optimization algorithm (GWO), and water cycle algorithm (WCA). The numerical results of the EWOA show that the combination of a hybrid solar PV-biogas generator with SMES-PHES can successfully reduce the LCC and increase reliability, making the distribution system work better.

A Three-Phase Phase-Modular Single-Ended Primary-Inductance Converter Rectifier Operating in Discontinuous Conduction Mode for Small-Scale Wind Turbine Applications

Small-scale wind turbines play an important role in distributed generation since customers can use their houses, farms, and business to produce electric energy. The development of the power electronics system that processes the electric energy from small-scale wind turbines is a concern due to cost, simplicity, efficiency, and performance trade-offs. This paper presents the results of applying a three-phase phase-modular single-ended primary-inductance converter rectifier to processing the energy of a small-scale wind turbine system. The rectifier was designed according to the specifications of a commercial small-scale wind turbine system and tested in an emulator workbench, providing experimental data on the operation of the rectifier in this application. The rectifier can process the energy of a non-sinusoidal three-phase system since the permanent magnet synchronous generator has trapezoidal waveforms. The results show that the rectifier has the advantages of (i) using the inductance of the generator as the input filter inductor of the rectifier, (ii) providing input currents with the same shape as the voltages and in phase without the use of a current control system, (iii) simplicity of control of the DC output voltage and PWM modulation, and (iv) phase-modular characteristics that allow operating with phase fault without any additional control techniques. Due to the operation in discontinuous conduction mode, low efficiency in high power and/or low input voltage specifications are disadvantages.

Asymmetric Trapezoidal Wave Modulation of Modular Multilevel Resonant DC/DC Converter for Current Stress Optimization

A modular multilevel resonant dc/dc converter (MMRDC) possesses high power and high voltage rating, which is adopted for high step-ratio interconnection in dc grid applications. However, the current stress and reactive power of MMRDC are high with the conventional quasi-square-wave modulation scheme when in a wide voltage range and light load conditions. Hence, this article proposes an optimized asymmetric trapezoidal wave (ATW) modulation scheme that reduces current stress over wide load and voltage ranges by separately modulating the duty cycles of string output voltage rising and falling processes. The time-domain mathematical model of MMRDC with the ATW modulation scheme is established. Then, based on the soft switching characteristic and reactive current analysis, the optimized operating point of MMRDC can be derived while considering low current stress and zero voltage switching constraint of low voltage side full-bridge switches. On this basis, the numerical solutions of optimized control variables are obtained, and a control block diagram is presented for the practical implementation of the optimized ATW modulation scheme. Finally, a 4kW MMRDC prototype is constructed, and the experimental results verify the correctness and effectiveness of the analysis and the optimized ATW modulation scheme.

High Speed and Low Leakage Power Voltage Level Shifter using Regulated Cross-Coupled Network

This concise presents a power efficient level shifter using regulated cross-coupled network with split inverter. With the use of regulated cross-coupled network, power dissipation of the pull-up region drastically decreases. Level shifters convert the voltage levels which are below the threshold voltage to the acceptable voltage levels by decreasing the transistor size. A Split inverter is used at the output to decrease the short circuit current. Modified Split inverter along with the load capacitor at the output is used to increase the speed and to decrease the power consumption. This LS can save 31% power compared to other techniques. The proposed level shifter works effectively at high speed and consumes less power. For simulation, LT spice tool of 50 nm technology and 90 nm technology is used.

A High Voltage Gain Interleaved DC-DC Converter Integrated Fuel Cell for Power Quality Enhancement of Microgrid

Fuel cells have drawn a lot of interest in recent years as one of the most promising alternative green power sources in microgrid systems. The operating conditions and the integrated components greatly impact the quality of the fuel cell’s voltage. Energy management techniques are required in this regard to regulate the fuel cell’s power in a microgrid. The active/reactive power in the microgrid should be adjusted in line with US Energy Star’s regulations whereas the grid current needs to follow the standard set by IEEE 519 2014 to enhance the power quality of the electrical energy injected into the microgrid. Uncontrolled energy injection from the fuel cell can have serious impacts including superfluous energy demand, overloading, and power losses, especially in high power and medium voltage systems. Although fuel cells have many advantages, they cannot yet produce high voltages individually to compensate for the demand of a microgrid system. Due to these reasons, the fuel cell must be interfaced with a DC-DC converter. This research proposes a novel high voltage gain converter integrated 1.26 kW fuel cell for microgrid power management that can boost the fuel cell’s voltage up to 20 times. Due to this high voltage gain, the voltage and current ripple of the fuel cell is also reduced substantially. According to the analysis, the proposed converter demonstrated optimal performance when compared to the other converters due to its high voltage gain and extremely low voltage ripple. As a result, the harmonic profile of the microgrid current persists with a reduced THD of 3.22% and a very low voltage ripple of 4 V. To validate the converter’s performance, along with extensive simulation, a hardware prototype was also built. The voltage of the fuel cell is regulated using a simplified proportional integral controller. The operating principle of the converter integrated fuel cell along with its application in microgrid power management is demonstrated. A comparative analysis is also shown to verify how the proposed converter is improving the system’s performance when compared against other converters.

Achieving Ultra‐High Voltage (≈10 kV) Triboelectric Nanogenerators

AbstractWith the intrinsic characters of high voltage and low current, triboelectric nanogenerators (TENGs) serving as green high voltage (HV) power source exhibit excellent practicability and safety compared to traditional HV power sources. To further simplify the TENG‐based HV power source system, a single electrode mode TENG (SE‐TENG) with simple wiring is first employed to generate ultra‐high voltage power in this work. By optimizing surface charge density and the thickness of packing layer between the primary electrode and reference electrode, a record value of 12.7 kV is achieved for SE‐TENGs. Furthermore, a calculation method based on a capacitance model is proposed to accurately measure the open voltage of TENG with a wide range (over 10 kV). The SE‐TENG‐based HV power source is successfully applied to power electronics and generates negative air ions for air cleaning. This work significantly simplifies TENG‐based HV power sources, and is expected to enrich the diversity of high‐voltage applications based on the reach of existing technologies.

Design of a Wireless Sensor Node for Overhead High Voltage Transmission Power Lines

High Voltage (HV) overhead power lines are systems of interconnected elements that deliver massive amounts of electrical energy over long distances. Electrical conductors, used as energy carriers, are designed according voltage, current, and temperature rated value. Monitoring the power line's state variables is emerging as a crucial topic aiming at both determining the optimal real-time capability and defining a suitable model for Health Index assessment. A Wireless Sensor Network (WSN), consisting of many distributed sensor nodes that communicate with each other, can be a suitable tool to improve line ampacity by maintaining the operating variables in respect of their rated values. This paper investigates the design of an Energy Management System (EMS) for a wireless sensor for HV power line application and proposes a maximum power point tracker (MPPT). The behavior of the MPPT is discussed in terms of electromagnetic field laws and properties of magnetic materials. Ordinary and extraordinary operating conditions are investigated. The theoretical results are validated through a series of experimental tests. A prototype has been realized and tested for real operating currents. The tests are also used to verify the sensor's resilience in the presence of harsh fault conditions.

Delay Mismatch Insensitive Dead Time Generator for High-Voltage Switched-Mode Power Amplifiers

The Design of efficient, safe, and reliable circuits is a prime objective in high-voltage (HV) electronic systems, such as switched-mode power amplifiers (PAs). One of the main causes of efficiency degradation and reliability problems, in these amplifiers, is the shoot-through current from the HV power supply to the ground. To eliminate such current, a dead time generator (DTG) is used to modify the signals propagating through the high-side and low-side gate drivers by adding a fixed dead time between them. However, any delay mismatch between these gate drivers can reduce the dead time to the point that it becomes negative. In this paper, an HV-DTG architecture is introduced. The architecture mitigates the effects of delay mismatch variations in gate drivers, which can result from parameters mismatch, fabrication process variations, and temperature variations. An HV switched-mode class-D power amplifier is used to illustrate the performance of the DTG. The amplifier is implemented in a low-cost <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.35~\mu m$ </tex-math></inline-formula> HV CMOS process. The total area of the PA is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.5~mm^{2}$ </tex-math></inline-formula> , where the DTG covers an area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.066~mm^{2}$ </tex-math></inline-formula> . A measured system’s efficiency of 95.14% is achieved with the shortest dead time of 10.8 ns, which is 1.38x smaller than the generated dead time in comparable state-of-the-art HV dead time generators.

A Five Level Modified Cascaded H-Bridge Inverter STATCOM for Power Quality Improvement

Multilevel converters have received serious attention on account of their capability of high voltage operation, high efficiency, and low electromagnetic interference. It has many advantages compared to conventional two-level inverters such as high dc-link voltages, reduced harmonic distortion, fewer voltage stresses, and low electromagnetic interferences. The multilevel converters have been used for STATCOM widely as it can improve the power rating of the compensator to make it suitable for medium or high-voltage high power applications. While deploying multilevel STATCOMs, designer’s role is to reduce the number of switching devices since, the total switching losses are proportional to the number of switching devices. The reduction in the count of switching devices also reduces the size and cost. In this paper, a five-level modified cascaded H-bridge inverter STATCOM is proposed for mitigation of harmonics. Modified Five-level CHB configuration is the most suitable as with lesser number of switches, give better performance resulting in a compact system. The PQ theory-based controller is developed for control of STATCOM operation. MATLAB simulation results are presented to demonstrate mitigation of harmonics.

Impact of doping concentration and recess depth to achieve enhancement mode operation in β-Ga2O3 MOSFET

High power switching applications necessitates the MOSFET to operate in Enhancement mode (normally OFF). Achieving enhancement mode operation in β-Ga2O3 MOSFET is challenging due to the difficulty in p-type doping. A TCAD simulation study is implemented to study the effect of the variation of doping concentration and recess gate to achieve enhancement mode operation. Subsequently, the device characteristics such as Id-Vd, Id-Vg and breakdown analysis are performed for β-Ga2O3 MOSFET with a channel thickness of 240 nm. On decreasing the doping concentration, the magnitude of threshold voltage reduces to 0V at a doping concentration of 1 × 1016 cm−3 causing enhancement mode operation but with significantly low drain current. However, this resulted in the increase in the device breakdown voltage. Adding Si3N4 passivation layer, further, enhanced the breakdown voltage. Subsequent study involved the impact of recessed gate to achieve enhancement mode operation. On increasing the recess depth, the magnitude of threshold voltage is reduced to 0V at a doping concentration of 8 × 1017 cm−3 with less impact on drain current. This also resulted in the increase in the device breakdown voltage. The obtained results will be instrumental for Ga2O3 community to develop and design enhancement mode β-Ga2O3 MOSFET for high power and high voltage applications.

Study on high-temperature and high-voltage insulation characteristics of polypropylene blend with highly packed elastomeric domains for power cable applications

In this paper, we report the high-temperature and high-voltage (HV) insulation characteristics of the polypropylene (PP) blend with highly packed elastomeric domains that showed excellent mechanical toughness in our previous study to find its suitability as insulation material for power cable applications. The main focus lies on tensile properties with thermal aging, thermomechanical behavior corresponding to the thermal transition, high-temperature volume resistivity and DC dielectric strength, and space charge accumulation behavior of the PP blend in comparison to the crosslinked polyethylene (XLPE). Our PP blend having low elastic modulus of approximately 266.9 MPa exhibited high tensile strength and elongation at break, and high-temperature stability as well. Using this PP blend, not only good HV insulating performances in volume resistivity and DC breakdown strength (BDS) were obtained similar to XLPE, but also adequate values were obtained at high temperature, even at 110 °C, which was not possible with XLPE. However, there was space charge accumulation and electric field distortion in the PP blend like XLPE, which needs to be suppressed. Therefore, our PP blend is expected to have the potential to replace existing XLPE as insulation materials for future HV power cables.

Effect of NaOH concentration as activator on calcined eggshell and its application for yeast microbial fuel cell

Eggshells may be utilized as an advanced material. Yeast microbial fuel cells may benefit with calcined eggshell at carbon felt anodes. Stability issues and poor power density prohibit its wider usage. We determined the eggshell-to-NaOH ratio for calcined eggshell anode material. Calcined eggshell with a 1:4 eggshell-NaOH ratio had a high maximum power density (31 mW.m−2) and voltage stability of 45 mV after 30 days incubation. The addition of NaOH activator may also increase crystal size and crystallinity to 145 nm and 43.92 %, respectively, which may accelerate electron transport as evidenced by a decrease in the energy band gap from 5.6 to 5.2 eV, as determined by DFT analysis. The addition of NaOH activator during incubation increased the surface area to 181.2 m2.g−1, improving the anode's potential to host yeast biofilms. Calcined eggshell with a 1:4 eggshell-NaOH ratio is a good anode for yeast microbial fuel cells.

Support Vector Machine Parameters Optimization for 500 kV Long OHTL Fault Diagnosis

Faults can seriously damage high-voltage (HV) power systems, particularly if they occur on the long overhead transmission line (OHTL) that connects the nuclear power plant (NPP) to the electrical grid. Finding OHTL problems quickly and accurately is essential for the economy, safety, and dependability of the HV power systems. It is essential to pinpoint the problematic phase to avoid unneeded power outages. Thus, one of the most crucial research challenges is now how to identify, classify, and locate OHTL faults. In this study, transient current with high frequency oscillations that arise immediately after a defect at the sending end is investigated in a single-circuit, single-side fed Egyptian 500-kV HV long OHTL. Asymmetric and symmetric faults and locations are also represented in the Alternative Transients Program-Electro Magnetic Transients Program (ATP/EMTP) simulation model under varying fault resistance and inception angles. The proposed solution in this paper is an Optimized Support Vector Machine (OSVM), whose characteristics are optimized via a mutant particle swarm optimization (MPSO) method to detect 500 kV long OHTL faults. The localizer model is also built for practical applications, including power system noise contaminating fault signals. The findings prove that the suggested approach locates the fault in 0.012 seconds from the start of the event, with a 0.0098 percent average percentage error, and without being impacted by differences in fault distance, fault resistance, noise, or fault inception angle. Additionally, the optimised classifier reaches a 99.85% accuracy rate, enhancing line system dependability and advancing nuclear system development.

Smart Grid based on Edge Cloud Computing

Grid means power or energy supply. An electric grid with the information and communication technology (ICT) is called smart grid. To use smart grid, smart meters are installed, and helps to do two way communications i.e consumers to suppliers and then again to consumers. Smart grid with edge computing is the smart solution where the consumers can track the high power voltage and because of that there will be no loss of energy. All the data gets transmitted using wireless communication. In tradition method consumers had only access of paying electricity bills but Smart grid overcomes the drawback of traditional method by providing two way communication. The consumers can also find out the graph of power supply at home, company, etc using smart grid. In future the cost of smart grid will get reduced and AI implementation will be activated and it will reduce the need for grid storage, and the consumers will able to operate the smart meters, so that the loss of electricity will be in control.

Performance investigation of modular multilevel inverter topologies for photovoltaic applications with minimal switches

Introduction. In recent years, a growing variety of technical applications have necessitated the employment of more powerful equipment. Power electronics and megawatt power levels are required in far too many medium voltage motor drives and utility applications. It is challenging to incorporate a medium voltage grid with only one power semiconductor that has been extensively modified. As a result, in high power and medium voltage settings, multiple power converter structure has been offered as a solution. A multilevel converter has high power ratings while also allowing for the utilization of renewable energy sources. Renewable energy sources such as photovoltaic, wind, and fuel cells may be readily connected to a multilevel inverter topology for enhanced outcomes. The novelty of the proposed work consists of a novel modular inverter structure for solar applications that uses fewer switches. Purpose. The proposed architecture is to decrease the number of switches and Total Harmonic Distortions. There is no need for passive filters, and the proposed design enhances power quality by creating distortion-free sinusoidal output voltage as the level count grows while also lowering power losses. Methods. The proposed topology is implemented with MATLAB / Simulink, using gating pulses and various pulse width modulation methodologies. Moreover, the proposed model also has been validated and compared to the hardware system. Results. Total harmonic distortion, number of power switches, output voltage and number of DC sources are compared with conventional topologies. Practical value. The proposed topology has been very supportive for implementing photovoltaic based multilevel inverter, which is connected to large demand in grid.

According transformer parameters to design a high voltage power

When the load is empty pulse width modulation high frequency and high voltage power’ stabilization depth can easily cause oscillation, and when the full load of the voltage regulation is too shallow the voltage regulation effect is not good, the reason for this phenomenon is because the equivalent ratio and load correlation. The first thing you need to do is to find out why you can avoid the problem early in the design. To find out the cause, should to know the influence of the high voltage rectifier circuit on the total gain of the circuit and the dispersed parameters of the high frequency and high voltage transformer.

An All Silicon Carbide 3 kV/540 V Series-Resonant Converter for Electric Aircraft Systems

In this work, an all silicon carbide (SiC) series-resonant converter (SRC) design is proposed and demonstrate to achieve a single stage dc-to-dc conversion from 3 kV to 540 V (±270 V) for future electric aircraft applications. The proposed SRC consists of a neutral-point-clamped converter using 3.3-kV SiC MOSFETs on the primary side, an H-bridge converter using 900-V SiC MOSFET on the secondary side and a high-frequency (HF) transformer. The detailed design methods for the SRC power stage and the HF transformer are presented. Especially, a tradeoff between the complexity for the cooling system and the need for high power density and voltage insulation is addressed in the transformer design, leading to a novel multilayer winding structure design to enhance the insulation capability and also the mechanical robustness. The proposed bobbin design is realized using additive manufacturing. The detailed analysis and modeling of the parasitic capacitance between sections introduced by fringe electrical field are presented. To validate the effectiveness of the proposed SRC design, a 25-kW converter prototype using 3.3-kV SiC discrete devices has been developed with a peak efficiency of 99.08% achieved in experimental studies.

Development of low power and high voltage RF signal generator

Ion confinement technology can be widely used in quantum computation and precision measurement. In ion trapping system, ions are stably trapped in ion trap by the action of external forces.Multi-ion confinement requires the joint action of electric field and magnetic field to make the trapped ions overcome the interaction force between ions and be stably confined in the same specific space. Therefore, the stability of the electric force and the magnetic force determines the stability of ion confinement. Although the electric field and magnetic field provided by traditional commercial instruments is stable, it is not conducive to the miniaturization of the device. According to the previous experiment of ion confinement, we have designed a radio frequency(RF) signal generator that can provide continuous low power and stable high voltage RF electric field for multi-ion confinement system to guarantee the stability of trapped ions in quadrupole linear ion trap, also to improve the tapped ions density.

A Mini-Marx Generator Powered by a Cockcroft–Walton Voltage Multiplier

A Marx generator generates a high-voltage (HV) pulse by charging two or more capacitors in parallel and then suddenly connecting them in series. In principles, a comparatively lower voltage dc power supply has to be used for the charging to achieve the desired HV. However, a moderate dc HV power supply is still quite expensive and bulky but not in full-time usage. In this work, a mini-Marx generator powered by a Cockcroft–Walton (CW) voltage multiplier has been proposed to form a more efficient, compact, but affordable configuration of pulsed HV power sources. For generating an HV in a range of 20–150 kV with the mini-Marx generator consisting of eight stages, a CW multiplier operating up to 3–20 kV is required. Numerical simulations using PSpice have been performed for validating the concept. For demonstration, a prototype of the 22-stage CW-powered four-stage mini-Marx has been built and tested with an ac voltage of 110 V at 60 Hz. In the experiment, the CW generator can reach 3.6 kV to power the mini-Marx, delivering an HV of 12.7 kV, consistent with the PSpice modeling. With an ac household voltage of 220 V at 60 Hz, a dc voltage of 5.2 kV can be obtained from the CW to charge an eight-stage mini-Marx generator, achieving an output voltage of 33 kV to drive a field emission-based X-ray source. The proposed CW powered mini-Marx generator is general and can be used as a compact pulsed voltage supply for some portable devices.

Improvement and Reduction of Self-Heating Effect in AlGaN/GaN HEMT Devices

GaN is one of the third-generation broadband semiconductor materials developed rapidly in recent years, and Algan/GanHEMT has a broad application prospect in the fields of high temperature, high power, high frequency and radiation resistance, etc. In recent years, gallium nitride based high electron mobility transistors have been widely used in emerging industries, such as 5G technology, new energy vehicles, unmanned aircraft and other fields, due to their high power and high voltage resistance. However, due to the high power density of HEMT devices, the self-heating effect will lead to a significant increase in the junction temperature of the device, which will seriously affect the performance, reliability, and lifetime of the device. In this paper, the temperature characteristics of GaN high electron mobility transistors (GaN HEMTs) are studied, and the effect of self-heating effect on GaN HEMT devices is analyzed. In order to reduce the device temperature and improve the reliability of the device, a new device structure is proposed in this paper. The new structure replaces the conventional silicon and Si3N4 with highly thermally conductive diamond and SiC as the substrate and passivation layer of the device, which facilitates the heat dissipation from the substrate and passivation layer. Also, the new structure employs a hybrid barrier layer and field plate. Simulation results show that the new structure has about 30% lower temperature peak, 47% higher output current, 28% higher transconductivity, and up to 18.22% higher current collapse rate compared to the conventional structure.