High Voltage Power Research Articles

Low-Cost High-Voltage Power Supply for Hydraulically Amplified Self-Healing Electrostatic Applications

HASEL (Hydraulically Amplified Self-Healing Electrostatic) actuators have gathered momentum in recent years; they are made of very-low-cost materials, making it easy for anyone to develop their own actuators, and they are “soft” and can achieve tasks that are very difficult to complete with traditional rigid actuators, e.g., grasping soft objects. Unfortunately, HASEL actuators are driven by high-voltage (HV) power supplies, which are expensive to control accurately and difficult to scale up for multichannel applications, e.g., prostheses. This paper presents a low-cost HV power supply designed for HASEL applications that generates 2–10 kV DC at 5% of the cost of the existing HV power supplies used in HASEL actuators. At the core of our design, there is a new control strategy based on controlling the charging and discharging of the actuator from the supply’s low-voltage (LV) side rather than switching the HV side with expensive HV optocouplers. Discharge is achieved via a secondary transformer and multiplier circuit, generating a negative HV output capable of discharging the HASEL effectively and safely up to 10 kV.

Feedforward Control Strategy of a DC-DC Converter for an Off-Grid Hydrogen Production System Based on a Linear Extended State Observer and Super-Twisting Sliding Mode Control

With the large-scale integration of renewable energy into off-grid DC systems, the stability issues caused by their fluctuations have become increasingly prominent. The dual active bridge (DAB) converter, as a DC-DC converter suitable for high power and high voltage level off-grid DC systems, plays a crucial role in maintaining and regulating grid stability through its control methods. However, the existing control methods for DAB are inadequate: linear control fails to meet dynamic response requirements, while nonlinear control relies on detailed model structures and parameters, making the control design complex and less accurate. To address this issue, this paper proposes a feedforward control strategy for a DC-DC converter in an off-grid hydrogen production system based on a linear extended state observer (LESO) and super-twisting sliding mode control (STSMC). Firstly, a reduced-order simplified model of the DAB was constructed through the structure of DAB. Then, based on the reduced-order simplified model, a feedforward control based on LESO and STSMC was designed, and its stability was analyzed. Finally, a simulation comparison of PI, LESO + terminal sliding mode control (TSMC), and LESO + STSMC control methods was conducted in a DC off-grid hydrogen production system. The results verified the proposed control method’s enhancement of the DAB’s rapid dynamic response capability and the system’s transient stability.

Contracted Capacity Optimization Problem of Industrial Customers with Risk Assessment

This study developed a risk assessment tool for contract capacity optimization problems using the ant colony optimization and auto-regression model. Based on the historical data of demand consumption, the Least Square algorithm, the Recursive Levinson–Durbin algorithm, and the Burg algorithm were used to derive the auto-regression model. Then, ant colony optimization was used to search for the auto-regression model’s best p-order parameters. To avoid the risk of setting the contract capacity, this paper designed the risk tolerance parameter β to correct the predicted value of the auto-regression model. Ant colony optimization was also used to search for the optimal contract capacity with risk assessment under the two-stage time-of-use and three-stage time-of-use. This study employed an industrial consumer with high voltage power in Taiwan as the research object, used the AR model to estimate the contract capacity under the risk assessment, and cut back electricity usage to reduce the operation cost. The results can be used as a basis to develop an efficient tool for industrial customers to select contract capacities with risks to obtain the best economic benefits.

SHE PWM based 21 level inverters with hardware analysis

Recently, the advancement of multilevel inverters (MLI) has been a crucial factor in high power and medium voltage applications. This MLI has multiple topologies and has been used in a variety of applications. Cascaded MLI is preferred over other forms of multilevel inverter topologies. Nonetheless, significant obstacles are encountered when implementing these topologies. They necessitate an increased number of switches, DC sources, capacitors, and diodes. Increased losses and total harmonic distortion (THD) will be present in the system. In addition, the MLI is more expensive. The better construction of a multilevel inverter results in more output levels with fewer switches, sources, and driver circuits, as well as low THD. A new single-phase cascaded asymmetrical DC voltage sources based multilevel inverter design and the selective harmonic elimination (SHE) approach are used to attain these goals. After confirming in MATLAB/Simulink, the hardware implementation of the multilevel inverter in 21 levels was completed in this article.

Investigating the effects of corrosion parameters on the surface resistivity of transformer’s insulating paper using a two-level factorial design

The integrity of the insulation in oil-filled power transformers, shunt reactors, and high voltage bushings can be affected when copper dissolves in the insulating oil and then deposits onto the paper insulation. The presence of dissolved copper in the oil increases dielectric losses, while copper deposition significantly improves the conductivity of the paper insulation. Various factors, including temperature, oxygen, sulfur groups, passivators, and ageing time, have been found to contribute to the acceleration of corrosion activity in transformer insulating oils. Unfortunately, there is a lack of extensive research focused on systematically analysing and measuring the impact of corrosion-related factors on the dissolution of copper in transformer insulating oils and the deposition of copper onto solid insulation surfaces (Kraft paper). Therefore, this study aims to thoroughly examine the effects of corrosion factors on copper and sulfur deposition on Kraft paper insulation when it is submerged in transformer mineral oil (TMO). Using a two-level (2k) factorial design, we investigated three crucial factors: i) oil temperature, ii) elemental sulfur concentration, and iii) ageing time. It is worth mentioning that the results obtained from the two-level factorial design indicate that the surface resistivity is primarily affected by the temperature of the oil. This factor alone explains a significant 38.68% of the observed variation. In order to improve predictability, a regression model was created to estimate the surface resistivity of TMO-impregnated paper insulation. This model takes into account factors such as oil temperature, elemental sulfur concentration, and ageing time.

Solar Based Multilevel Inverter f o r BLDC Motor Drive

The BLDC motor is widely utilized in high power and low voltage applications because to its simple construction, great efficiency, low maintenance requirements, and low cost .Furthermore, considering their size, they have a lot of torque and power output. The BLDC motor is powered by an alternating current source and is operated straight from the AC supply port, despite being a DC motor in this case. The main drawback is that any disruptions in the source will have an impact on the applications that use BLDC motors in the industrial context. So, to avoid this, there should be a converter and an inverter intermediary between the motor and the source. One of three methods can be used to drive the BLDC motor. 1. Two-level inverters based on pulse width modulation (PWM). 2. An multiple-level working inverter. 3. A multilevel inverter with neutral clamping. Using a multicarrier PWM technique, the suggested inverter may lower the output signal's harmonic content. It is capable of generating very good motor currents. In this instance, a three-level diode clamped multilevel inverter can be used to accurately control the speed of a BLDC. This study's primary goal is to demonstrate how to run a BLDC drive with an inverter to lower harmonics. A diode clamped multi-level inverter is a device that converts voltage to current. An improved version of this strategy is provided by this research. Using the MATLAB Simulink software tool, one can assess the system's overall effectiveness by simulating the neutral clamp multilevel inverter-based drive system's functioning. In the event of a power outage, the entire application will cease to function and generate output. Under order to increase the output and supply reliability of power, renewable energies must be used under these circumstances. There are many renewable energy sources available; however solar photovoltaic systems are the better option because of their benefits over traditional power sources. A diode clamped multi-level inverter was used. A diode clamped multi-level inverter was used to drive the BLDC.

A Study on Simultaneous Measurement of Partial Discharge in Epoxy Resin Insulator using IMC and Rogowski Coil

In practice, field measurement of partial discharge is easily suffered by interferences due to the noisy signal has been mixed with the resulting partial discharge signal. Therefore, the detection and measurement of PD are important to monitor the insulation life in high voltage (HV) power equipment. The paper presents the simultaneous measurement of partial discharge (PD) pulse parameters using the impedance matching circuit and the Rogowski coil sensor to study the features of partial discharge on the epoxy resin insulator. Two different thicknesses of samples were used to observe the PD pulse parameters with the voltage applied vary depending on the thickness of the sample to attain constant electric field intensity for both samples. The step response parameters resulted from the measurement can be used as a time domain features to discriminate various types of PD in HV power equipment. Thus, the PD can be observed clearly, maintenance can be performed, and the performance of the power system can be improved.

Adsorption and sensing SF6 decomposed gases (SO2, SO2F2, SOF2, H2S, and HF) on Ti and Co decorated B4CN3 monolayer- A DFT study

With frequent switching of high power and high voltage circuits, SF6 gas decomposes into low fluorine gases, which causes deterioration of SF6 gas. Therefore, such decomposed gases must be sensed and captured timely for the smooth operation of the SF6 power circuit breaker (PCB). The current study aimed to employ density functional theory (DFT) calculations to explore the adsorption and gas sensing properties of SF6 decomposed products (SO2, SO2F2, SOF2, H2S and HF) on titanium (Ti) and cobalt (Co) decorated B4CN3 monolayer. The findings revealed that pure B4CN3 could not capture gas molecules with sufficient adsorption energy and faced instantaneous release. Similarly, Ti and Co decoration can significantly activate the B4CN3 for adsorption and gas sensing. Adsorption analysis showed that SO2, SO2F2, SOF2, H2S, and HF chemically adsorbed on Ti decorated B4CN3 monolayer having adsorption energy of −1.31, −1.61, −1.35, −1.20, and −1.01 eV. Whereas, gas adsorption on Co decorated B4CN3 has −1.29, −1.58, −1.31, −1.18, and −0.95 eV, respectively. The gas sensing mechanism was evaluated by calculating band structure, work functions, and transport transmission. Despite having comparatively lower adsorption energies, Co decorated B4CN3 was found to be more sensitive to all gas molecules than Ti decorated B4CN3. The release time of gas molecules at room temperature can be shortened to nanoseconds either by rising temperature to 498 K or by just UV exposure at 298 K. Our study provides some significant theoretical insights into the gas sensing abilities of Ti and Co decorated B4CN3 monolayer for sensing SF6 decomposed products.

A current injection method for converter power loss representation in electromagnetic transient simulation

The power-electronics converters are increasingly applied in modern power system, which contains various sub-systems, such as renewable energy power plants and high voltage direct current transmission systems, etc. The electromagnetic transient simulation has been one of the important tools for the study of complex system containing large numbers of power converters. The coordination control of the power converters and corresponding power generation and load units is one of the challenges ensuring stability and obtaining optimal efficiency. However, the detailed modeling of the power converters considering the conduction and switching losses can cost a great number of computation resources, which makes it difficult to simulate a large system. This work proposed a current injection method for converter power loss representation, which can accurately consider the conduction and switching losses of the power-electronics switches with low computation complexity. A look-up table (LUT) of the power loss ratio is calculated before the simulation, and a current source representing the power loss is connected in parallel with the converter to track the reference loss generated by the look-up table. The proposed method can be combined with multiple converter modeling schemes, such as the two-resistance model, the switching-function model, and the average value model, etc. The topologies of the two-level converter and the modular multi-level converter (MMC) were used in the case studies to demonstrate the effectiveness of the proposed method. Compared to the device-level model, the simulation power loss deviation is 0.64% and 4.13% applying the current injection method model in the case studies of the two-level converter and the MMC.

High power voltage multiplier (VM) PFC Converter with inherent ZCS Characteristics and high step-ip gain for enhanced low-line efficiency

In this paper, a Voltage Multiplier (VM) converter configuration has been designed for high Power PFC application, ensuring reduced losses and high system efficiency.The conventional PFC system is improved with adding VM circuit configuration that enhances the static gain features with moderate duty ratio (D), and hence, the reverse recovery (RR) issue is resolved. The VM section inherently adds two main specific features of clamping behavior and ZCS phenomenon to the PFC system. An experimental prototype of 2 kW, 600 V VM PFC converter configuration is designed and its effectiveness is validated under low line input of 100 V , operating at a high duty ratio, D = 0:67. The Real-Time Interface (RTI) feature of dSPACE1104 and MATLAB/Simulink are used to give the control signal for the verification of the system. Always, less than half of the output voltage (300 V ) appears across the switches of the converter, hence, voltage stress of the switch is minimized. Also, ZCS phenomenon is evident during switching commutations due to the snubber circuit behavior of the resonant tank, included in the proposed PFC converter. Hence, the overall system efficiency is improved. Furthermore, higher system efficiency is maintained for different rating which has been tested in this research work.

Voltage Source Converter based High Voltage Direct Current Transmission: A Comprehensive Review of Control Strategies, Developments and Trends

The continuous increasing progress in high power and high voltage semiconductor devices leads to have a substantial impact on optimization and effective management of electric grids. These developments have great influence on High Voltage Direct Current (HVDC) and flexible ac controller technologies. This article gives an outline of the innovations in Voltage source Converter (VSC) based HVDC technology. VSC based HVDC technology offers decent advantages which includes interconnection of asynchronous networks, bulk power transmission and voltage stability support. VSC based HVDC technology niche utilities to grab opportunities in incorporating large scale renewable energy sources to the grid, especially on shore /offshore wind energy to the grid. Furthermore, VSC-based HVDC technology is essential for maintaining voltage stability in networks of interconnected grids. In the face of changing loads and the incorporation of renewable energy, these systems help to maintain grid dependability and resilience by offering dynamic voltage management and wattless power support.This article highlights the transformative potential of VSC-based HVDC technology in modernizing and future-proofing electric grids. By leveraging the latest innovations in semiconductor devices and control technologies, VSC-based HVDC systems empower grid operators to overcome existing challenges and embrace the opportunities presented by the evolving energy landscape.

Ultrahigh energy storage in multilayer BiFeO3–BaTiO3–NaTaO3 relaxor ferroelectric ceramics

The rising challenge of high-density electric energy storage has accelerated the research of electric energy-storage capacitors due to their high power density and voltage resistance, excellent temperature stability, and environmental friendliness.

High voltage in nuclear applications: Occupational safety aspects and standards

High voltage (HV) plays diverse and critical roles that in both nuclear power generation and nuclear instrumentation, contributing to the efficiency, safety, and precision of various processes within the nuclear domain. The basic detection component of nuclear instruments is the nuclear detector, which needs direct current HV power supply. Exposure to HV electrical systems can cause serious injuries, fatalities, and damage to equipment if proper safety measures are not followed. Comprehensive safety measures, such as proper training, adherence to safety procedures, use of personal protective equipment, equipment maintenance, regular inspections, and compliance with relevant safety standards and regulations, are essential to mitigate hazards arising from HV applications. HV safety and standards are critical aspects of HV occupational practices as they ensure the protection of personnel, machine, and workplace safety. A close study points to certain inadequacies and weaknesses in the existing standards. These include a lack of universal standards, insufficient coverage of nonelectric hazards or indirect safety hazards, deficient or no focus on human factors, and limited consideration of evolving and new technologies. In the last portion of this article, the standards followed at the High Voltage Pulsed Power Lab, Control Instrumentation Division, BARC are discussed along with the safety practices that are observed in the routine operation of different high voltage systems.

Degradation and Failure Mechanism of p-GaN Gate E-Mode GaN HEMTs

GaN-based power transistors are becoming pivotal devices for high power and high voltage operation due to their higher breakdown voltage, higher carrier mobility because of two-dimensional electron gas (2-DEG), better thermal resistance, higher frequency switching, and lower on-state resistance (RON) [1]. P-GaN gate E-mode GaN HEMTs have emerged as a center of extensive research to understand their operation and reliability [2]. However, one of the reasons the E-mode GaN HEMTs are not yet successfully utilized to their maximum potential is the lack of complete understanding of gate breakdown. Gate degradation of p-GaN gate E-mode GaN HEMT is less understood because of the complexities involving the operating conditions and variables such as gate length, the acceptor doping concentration in the p-GaN layer [3], p-GaN gate thickness, and design of the device [4-5]. To outline a consistent degradation mechanism, this work aims to present an electro-physical model of gate breakdown in p-GaN gate E-mode HEMTs.Lateral E-mode GaN HEMT devices with p-GaN gate configuration are used for this study. According to the Scanning Transmission Electron Microscopy (STEM) imaging of a new device, the AlGaN barrier is 10 nm thick, and the p-GaN cap is 65 nm. The gate-source and gate-drain lengths are 0.5 micrometer and 2.5 micrometer, respectively. The gate length defined by the p-GaN layer is 0.5 micrometer and the edges of the gate metal are pulled in from the top edge of the p-GaN layer by 40 nm. A 0.7 micrometer-long, source-connected field plate is over the p-GaN gate. The p-GaN gate is subjected to static stress to induce accelerated breakdown. Devices were stressed with HP 4155 Semiconductor Analyzer. The electrical measurements were performed with the source, drain, and substrate connected to the ground. FEI 200 Nova was used for Scanning Electron Microscopy (SEM) imaging and Focused Ion-Beam (FIB) milling. ARM JEM-200F with a Cs corrector was used for STEM.Our results show that time-to-fail is highly dependent on device operating conditions. We found no correlation between time-to-fail and initial gate current (IG0). Instead, a higher impact of temperature was found on the gate current of the device (IG) and time-to-fail at 100 °C. Gate failure at constant voltage stress was a single-stage failure. Under constant current stress, on the other hand, the gate shows a multi-stage failure. The breakdown mechanism depends on the impact of static stress on the gate degradation, starting with increased gate current leading to Schottky barrier leakage and finally to catastrophic contact failure. Our study shows that the metal/p-GaN interface at the gate finger becomes the weakest part of the gate stack, likely to be the initiation point of degradation. Metal/p-GaN interface and surface defects develop as percolation paths acting as leakage sources, and nano-cracks have been observed in the gate cap. FA also shows physical degradation at the metal/p-GaN cap due to electrical stress. Observed physical damage in the gate region is correlated to the gate leakage characteristics to develop an electro-physical failure model for gate breakdown in p-GaN gate E-mode GaN HEMTs.

Deep-learning assisted biomimetic self-powered wireless electronic noses system enabled by triboelectric discharge

Electronic noses, inspired by the mammalian olfactory system, have revolutionized various industries including food, environment, medicine, and rescue. They detect gases by using sensor arrays and provide real-time information. However, current electronic noses demand batteries as the power source, limiting their applications and requiring frequent maintenance. Wireless transmitter modules can also increase battery dependence and introduce high energy consumption. Moreover, gas sensors used in electronic noses lack multidimensional information identification ability. Here, we have developed a self-powered, wireless electronic nose system based on triboelectric discharge. By converting mechanical energy into high-voltage power, this system can initiate gas discharge and produce wireless signals that contain valuable gas information. With deep learning, it can recognize up to 60 different types of gas atmospheres with 93.8% accuracy, including 5 gas components with 12 different gas pressures. The system with a visualization program is designed for wireless, real-time gas monitoring toward applications in health monitoring, precise manufacturing, and high-tech fire rescue operations.

Sustainable charging station allocation in the distribution system for electric vehicles considering technical, economic, and societal factors

With a greater emphasis on achieving sustainable objectives, attention has switched to the electrification of the transportation sector. In the modern transportation industry, the burgeoning number of electric vehicles is progressively leading to the phase-out of petroleum-based cars. The quick deployment of electric vehicles, on the other hand, is heavily reliant on the coordinated and rapid construction of an electric vehicle charging ecosystem. The fusion of the electric vehicle charging ecosystem in today's distribution network with penetration of randomly dispersed photovoltaic systems is intricate since it might result in high power losses and voltage variances above permissible limits. This study employs the Grey Wolf Optimization to organize the charging ecosystem in the grid in order to maximize the profits while remaining within the legal bounds of limitations and maintaining user comfort in mind. The study incorporates the human inconvenience factor to provide the better results. The whole research is carried out using an IEEE 33 bus test system, which replicates a balanced radial distribution network for the deployment of electric vehicle charging ecosystems. It has been discovered that strong buses in the system can endure the installation of fast-charging ecosystem up to a certain point. In contrast, deployment of charging ecosystem on weak buses obstructs the functioning of the power system with increased losses, penalties and frequent blackouts.

Investigation of thermal and strength characteristics of a natural backfill composite inspired by synergistic biochar–biopolymer amendment of clay loam

Thermally active structures such as crude oil pipelines and high-power voltage cables are usually embedded within local soils for their substructural stability. Based on site requirements, soils are amended with synthetic cementitious materials to improve their strength. However, synthetic binders such as cementation, geo-polymerization, and bio-cementation undermine thermal insulation while improving strength. Moreover, commonly used synthetic binders such as cement and lime are extremely harmful to the geoenvironment due to their hyper-alkalinity and high carbon footprint. Therefore, this study proposes a novel backfill composite consisting of clay loam, biochar, and biopolymer for superior thermal insulation and strength characteristics. Local soil containing high clay content was chosen due to its low thermal conductivity and potential to form stable hydrogen bonding with the biopolymer. The clay loam is amended with 2.5% to 7.5% ( w/ w) biochar and 0.5% to 1.5% ( w/ w) of biopolymer and their various combinations. Out of nine soil–biochar–biopolymer composites devised in the current study, six composites exhibited superior strength and lowered thermal conductivity than the plain soil in both conditions, i.e., optimum moisture state and upon drying. The findings of this study establish the synergistic attributes of biopolymer and biochar amendment for developing a high-strength thermal-insulating soil composite.

Design a 25-level inverter topology with less switching devices fed by PV systems

<span lang="EN-US">Multilevel inverter (MLI) technology has lately emerged as one of the most popular solutions for high power and medium voltage energy management. MLIs have many benefits and require more switches for higher levels, which are considered disadvantaged. This could result in large size and extremely expensive cost for the MLI. So, in order to overcome this problem, a new MLI topology is proposed with reduced number of switches. A 25‐level inverter fed by isolated unequal photovoltaic panels as DC sources is chosen in this study. The structure of DC voltages is chosen as (1:1:5:5) Vdc. The proposed approach, which is created using twelve switches, is ideally suited for a high-power application. Multi-carrier with a sinusoidal PWM technique is programmed as a controller. According to the simulation findings, a single-phase system's output voltage and current total harmonic distortion (THD) values are 1.2% and 0.462%, respectively, while a three-phase system's values are 1.07% and 0.342%. These findings prove that the power circuit and investigation were successful.</span>

A self-powered extensible P–SSHI array interface circuit with thermoelectric energy assistance for piezoelectric energy harvesting

In this paper, a self-powered extensible parallel synchronized switch harvesting on inductor (EP-SSHI) interface is presented. The proposed interface addresses multiple piezoelectric transducers (PZTs) with arbitrary phase differences, while avoiding the conflict of accessing the single inductor simultaneously. In addition, the proposed interface enhances the voltage flipping performance of the PZT by incorporating thermoelectric energy assistance to increase its output power. Measurements demonstrate that the voltage flipping efficiency of the EP-SSHI with thermoelectric energy assistance (EP–SSHI–TEA) was increased to 53.33% with the assistance of 75 mV thermoelectric energy. Experimental results reveal that the proposed interface can effectively harvest energy from multiple PZTs with any phase difference. Compared with the conventional full bridge rectifier, the EP-SSHI achieves 3.63x power improvement and 6.42x load voltage range. Relative to other advanced circuits, the proposed interface strikes a superior balance between high output power and wide output voltage range while maintaining circuit simplicity and extensibility.

Third harmonic injection control for co‐phase traction power supply system using direct AC/AC full‐bridge modular multilevel converter

AbstractAs the full‐bridge modular multilevel converter (FB‐MMC) enables direct three‐phase AC voltage to single‐phase AC voltage conversion with good power quality and high voltage level, it is suitable for the co‐phase traction power supply system. However, voltage deviation occurs between arms when the direct AC/AC FB‐MMC operates in equal or similar frequency conditions. To solve this problem, a voltage balancing control based on third harmonic injection of co‐phase power supply system using direct AC/AC FB‐MMC is proposed. With the third harmonic injection, voltage balancing between arms is ensured and the capacity of FB‐MMC is enhanced. The third harmonic voltage is directly obtained from existing signals and the third harmonic current reference is produced by simple proportional‐integral (PI) controller. The effect of the third harmonic currents under different voltage ratios and phase difference is quantitatively analyzed, optimized range of voltage ratio and phase difference are obtained to minimize arm currents increment and reduce overrating of converter currents. In addition, a comparison between the proposed and the conventional control scheme is studied, showing the superior of proposed method in cost and performance. Finally, the effectiveness of the proposed scheme is verified by simulations and experiments.