Simple Power Supply Research Articles

Electromagnetic transient simulation of power system based on PSCAD calling ADPSS

Abstract As the power system gradually expands into a massive scale, time-varying complex system, the requirements for simulation analysis software are constantly improving, and electromagnetic transient analysis plays a crucial role in the power system. Therefore, to solve the possible limitations of this traditional simulation method, this paper proposes an electromagnetic transient simulation of power systems using PSCAD, called ADPSS. Firstly, according to the basic overview and advantages of the electromagnetic transient analysis program PSCAD/EMTDC and the mathematical model software package ADPSS, the interconnection principle and implementation method between PSCAD/EMTDC and ADPSS are studied, and a simple power system power supply model is established in PSCAD. Then, the principle of PSCAD-ADPSS interface technology is studied. The electromagnetic transient simulation is carried out in the interface environment, and the interface custom components are designed. Finally, by conducting a comparative analysis of the simulation outcomes, it is found that the simulation waveforms obtained in the two simulation environments are almost the same, which shows the effectiveness of PSCAD-ADPSS interface simulation technology in electromagnetic transient analysis and has the potential to enhance the precision and dependability of electromagnetic transient simulation.

Non-Woven Fabric Thermal-Conductive Triboelectric Nanogenerator via Compositing Zirconium Boride.

With the vigorous development of the Internet of Things, 5G technology, and artificial intelligence, flexible wearable sensors have received great attention. As a simple and low-cost power supply in wearable sensors, the triboelectric nanogenerator (TENG) has a wide range of applications in the field of flexible electronics. However, most polymers are thermally poor conductors (less than 0.1 W/(m·K)), resulting in insufficient heat dissipation performance and limiting the development of TENG. In this study, a high-performance non-woven fabric TENG with strong thermal conductivity (0.26 W/m·K) was achieved by introducing ZrB2 into the polyurethane (PU) matrix. The excellent output performance with an open circuit voltage (Voc) of 347.6 V, a short circuit current (Isc) of 3.61 μA, and an accumulated charge of 142.4 nC endows it with good sensitivity. The electrospun PU/ZrB2 composites exhibit excellent sensing performance to detect body movements in situ, such as pressing, clapping, running, and walking. Moreover, the generated power can light up 224 LED bulbs as a demonstration of self-powering ability.

Self‐Sustained and Coordinated Rhythmic Deformations with SMA for Controller‐Free Locomotion

This study presents a modular, electronics‐free, and fully onboard control and actuation approach for shape memory alloy (SMA)‐based soft robots to achieve locomotion tasks. This approach exploits the nonlinear mechanics of compliant curved beams and carefully designed mechanical control circuits to create and synchronize rhythmic deformation cycles, mimicking the central pattern generators prevalent in animal locomotions. More specifically, the study elucidates a new strategy to amplify the actuation performance of the shape memory coil actuator by coupling it to a carefully designed, monostable curve beam with a snap‐through buckling behavior. Such SMA‐curved beam assembly is integrated with an entirely mechanical circuit featuring a slider mechanism. This circuit can automatically cut off and supply current to the SMA according to its deformation status, generating a self‐sustained rhythmic deformation cycle using a simple DC power supply. Finally, this study presents a new strategy to coordinate (synchronize) two rhythmic deformation cycles from two robotic modules to achieve efficient crawling locomotion but still use a single DC power. This work represents a significant step toward fully autonomous, electronics‐free SMA‐based locomotion robots with fully onboard actuation and control.

Compact MV-Insulated MHz Transformer-Coupled Gate Driver With Staged Turn-Off Scheme for Series-Connected Power Devices in DC Circuit Breaker Applications

The short-circuit protection equipment of dc circuit breaker (DCCB) is important for the dc grid. Also, the series-connected power devices are usually employed in the solid-state circuit breaker (SSCB) or hybrid circuit breaker (HCB) to meet the clamping voltage requirement. A simple passive gate driver and power supply solution is a critical component to drive the circuit breakers more cost-effective and reliable. This article proposed a novel compact MV-insulated transformer-coupled gate driver method, which combines the auxiliary power and gate signal together. The proposed high-frequency-modulated multilevel transformer voltage enables both the simultaneous and the staged turn-off schemes. Besides, the cascade high- and low-voltage transformer structures simplify the insulation design and demonstrate better scalability. The common-mode current could be suppressed as well using this structure. The design example of a compact 2-MHz high-voltage planar transformer with >13-kV partial-discharge-free insulation capability is illustrated. Finally, the simulation and experimental results are also given to demonstrate the feasibility of the proposed gate driver method.

Electrokinetic Enrichment and Label-Free Electrochemical Detection of Nucleic Acids by Conduction of Ions along the Surface of Bioconjugated Beads.

In this paper, we report a method to integrate the electrokinetic pre-enrichment of nucleic acids within a bed of probe-modified microbeads with their label-free electrochemical detection. In this detection scheme, hybridization of locally enriched target nucleic acids to the beads modulates the conduction of ions along the bead surfaces. This is a fundamental advancement in that this mechanism is similar to that observed in nanopore sensors, yet occurs in a bed of microbeads with microscale interstices. In application, this approach has several distinct advantages. First, electrokinetic enrichment requires only a simple DC power supply, and in combination with nonoptical detection, it makes this method amenable to point-of-care applications. Second, the sensor is easy to fabricate and comprises a packed bed of commercially available microbeads, which can be readily modified with a wide range of probe types, thereby making this a versatile platform. Finally, the sensor is highly sensitive (picomolar) despite the modest 100-fold pre-enrichment we employ here by faradaic ion concentration polarization (fICP). Further gains are anticipated under conditions for fICP focusing that are known to yield higher enrichment factors (up to 100,000-fold enrichment). Here, we demonstrate the detection of 3.7 pM single-stranded DNA complementary to the bead-bound oligoprobe, following a 30 min single step of enrichment and hybridization. Our results indicate that a shift in the slope of a current-voltage curve occurs upon hybridization and that this shift is proportional to the logarithm of the concentration of target DNA. Finally, we investigate the proposed mechanism of sensing by developing a numerical simulation that shows an increase in ion flux through the bed of insulating beads, given the changes in surface charge and zeta potential, consistent with our experimental conditions.

Controlled electrochemical surface exfoliation of graphite pencil electrodes for high-performance supercapacitors.

A controlled surface exfoliation method for graphite pencil electrodes using an environmentally friendly, low cost and scalable electrochemical process is reported. A simple direct current power supply in a neutral medium is used for inducing graphene formation on the electrode surface in a controlled manner. The electrochemical properties of the surface exfoliated electrode are characterized, displaying a >300× increase in the electrochemical surface area and >50× decrease in the electrode resistance after exfoliation. The surface graphene layer is characterized using electron microscopy, Raman, infrared, X-ray photoelectron, and energy dispersive X-ray spectroscopies and X-ray diffractometry showing a fully exfoliated surface, formation of surface defects and mild surface graphene oxidation while maintaining an intact graphitic crystal structure. The surface exfoliated electrode is tested as a supercapacitor demonstrating more than 2 orders of magnitude improvement over non-exfoliated electrode in both 3-electrode and 2-electrode setups and achieving a high areal capacitance of ∼54 mF cm-2. The benign nature, low cost, scalability of our controlled surface exfoliation methodology, and its significant impact on the electrochemical properties of the electrode make it very promising for further investigation in various applications such as energy storage and conversion, sensors, and catalysis.

Preliminary Design of a New Type of Power Supply Similar to Flat-Top Pulsed High Magnetic Fields

This paper describes a simple, compact and cost-effective capacitor pulse power supply, which only uses a single magnet coil and two capacitors of different voltage and capacity levels to form a special circuit structure. It can realize a long pulse magnetic field similar to the flat top wave, so as to meet some scientific experiments that require higher magnetic field strength and stability. Through the reasonable design, the rising edge of the magnetic field waveform is accelerated, the stability of the waveform top is maintained for a relatively long time, and the energy of the magnet is rapidly transferred and released by controlling in the falling stage of the magnetic field. This design reduces the heating of the magnet due to heat accumulation, thus shortening the cooling waiting time of the magnet and improving the service life of the magnet.

Research on reliability evaluation of complex distribution network considering N-1 verification

With the rapid development of power system, the distribution network structure is gradually mature and the connection situation is more complex. The traditional distribution network reliability calculation method can not accurately calculate the reliability index of complex distribution network. Based on the traditional simple power supply reliability evaluation method of radial distribution network, this paper completely considers the influence of circuit breaker, tie switch, branch line, standby transformer and other equipment, and puts forward an improved network equivalence method model. The model first treats the complex distribution system in layers, and then gradually equates it into a simple radial distribution network to calculate the reliability of the system. At the same time, this paper analyzes the distribution network with multi connection structure in a provincial capital city. The results show that this model simplifies the complexity of distribution system reliability calculation, improves the accuracy and speed of reliability calculation, and more truly reflects the reliability of actual distribution system.

VxG Pattern-Based Analysis and Battery Deterioration Diagnosis

This paper presents the results of an analysis using the direct current internal resistance (DCIR) method on a nickel-cobalt-manganese oxide (NCM)-based battery with a nominal capacity of 55.6 Ah. The accelerated degradation test was performed on V0G, V1G, and V2G patterns, representing existing simple power supply, smart charging control, and bi-directional charge/discharge control, respectively. We assumed V0G, V1G, and V2G patterns and conducted charging and discharging experiments according to the set conditions. According to the pattern repetition, changes in the internal resistance of DCIR and AC-impedance were analyzed and battery deterioration was diagnosed. By comparing DCIR and AC-impedance, we confirmed that the changes in internal resistance has a similar trend. In particular, we propose a new DCIR analysis method in the “stop-operation” part rather than the traditional DCIR method. In the case of traditional DCIR method, time is required for the battery to stabilize. However, the newly proposed DCIR analysis method has the advantage of diagnosing the deterioration of the battery during system operation by analyzing the internal resistance without the stabilization time of the battery.

Impact of improvements in ZnO thin film solution process on ZnO/Cu2O solar cell performance

ZnO semiconductor is an ideal n-type window material for a solar cell owing to both the abundance of zinc in nature and its stable structure. The preparation of ZnO thin films with proper crystallinity is still possible only with expensive production methods. It is challenging to grow high quality ZnO thin film by the sol-gel spin coating method which is simple and low-cost. Generally, ZnO thin films prepared by spin coating method demonstrate poor crystallinity properties. The crystallinity of ZnO and hence the heterojunction efficiency can be enhanced, by simply improving the solution process. Additionally, the comparison of solar cell efficiency based on the quality of ZnO thin film prepared by the spin coating method in the literature is still a deficiency. Therefore, in this study, the semiconductor properties of ZnO thin films prepared by a spin coating method using the improved solution process compared to our previous study were investigated. The p-Cu 2 O thin film electrodeposition was achieved by our novel low-cost two-electrode cell utilizing a simple DC power supply and microammeter. The semiconductor properties of ZnO thin films and their impacts on ZnO/Cu 2 O bilayer heterojunction efficiency were elaborated by means of structural, optoelectronic, and I–V characterizations. The crystal quality of ZnO has been significantly improved, and a large increase in the output current and voltage of the fabricated solar cells has been achieved. • The preparation of ZnO thin films with proper crystallinity require expensive vacuum based equipment. • It is challenging to grow high quality ZnO thin film by sol-gel spin coating method which is simple and low cost. • By simply improving the solution process, the ZnO/Cu 2 O solar cell output voltage and current can be enhanced. • Investigation of various combination of ZnO/Cu 2 O based heterostructures.

Analysis of propulsion units dedicated to test stands for aviation systems

This paper presents an analysis of selected propulsion units dedicated to test stands for unmanned aircraft systems. It focuses on engines suitable for aircraft with a maximum take-off mass up to 150 kg. The study includes an analysis of propulsion units that can be used to power systems on stationary test stands dedicated to advanced research and measurement of prototype aerospace technologies intended for use in rotorcraft. The analysis of propulsion units shows that electric units are a better choice for powering UAV rotorcraft test stands. Their main advantages include the possibility to simplify the construction of the device by eliminating gears and to mount the motor in a vertical position, simpler power supply, cooling and control systems and the lack of an exhaust system. Additional advantages are undoubtedly lower vibration generation, cheaper and easier operation as well as better comfort.

Load Model Identification using Steady-state Measurements for Power System Control

Power system control requires verified models of all its elements: generators, transformers, transmission lines, and power system loads. To identify load model parameters, the measurement data are used. The paper discusses the possibility of using steady-state measurements instead staged field test data. This requires taking into account an unobvious effect-the network response. The network response is due to the probabilistic nature of the power and voltage changes and the correlation between them. The network response effect is demonstrated using a probabilistic load model and a simple power supply scheme.

Preparation of silver nanoparticles in a high voltage AC arc in water

The article presents for the first time the synthesis of silver nanoparticles in an electric arc of high-voltage alternating current with a frequency of 50 Hz. In particular, the method and apparatus necessary for the preparation of nanoparticles in water solution is discussed. Current–voltage characteristics depending on the mutual distance between the electrodes are presented which show a very high stability of the generated discharge phenomena. The obtained nanoparticles were examined using various analytical techniques such as UV–Vis spectroscopy, dynamic light scattering (DLS), zeta potential, energy dispersive X-Ray analysis (EDS), X-ray diffraction (XRD), and X-ray fluorescence (EDXRF). The morphology, surface and size of the obtained nanoparticles was carried out using transmission electron microscopy (TEM) and scanning TEM (STEM) equipped with the annual dark-field imaging scanning atomic-scale chemical mapping (STEM). The designed simple power supply unit consisting of an autotransformer and a microwave oven transformer (MOT) makes the preparation of silver nanoparticles both simple and economical.

Пространственный анализ конкуренции и сотрудничества деревьев в культурах сосны

In forest cultures of scots pine 1 in bonita at the age of 55 years with a standing density of 940-1620 pcs./ha with a fullness of 0.84-1.02 on an area of 1.9 ha, places with low and medium density (5 sample areas, 433 trees) were selected to study the influence of microcenoses on the diameters of trees in their center. To do this, in the "ArcMap-ArcView" program, food polygons for the age of 30-40 years and 41-55 years were built around the trees. Five indicators were used in the spatial analysis of the data: 1 - simple pressure of neighbors: the diameters of the neighbors on the polygon were summed up; 2 - specific pressure of neighbors: indicator 1 was divided by the feeding area of the central tree; 3 - pressure of neighbors taking into account the distances to the central tree: the diameter of the neighbor was divided by the distance to the central tree and the data were summed; 4 - specific pressure of neighbors taking into account the distances: indicator 3 was divided by the feeding area of the central tree; 5 - cooperation of trees on the sides of the polygon: the diameter of the neighbor was multiplied by the contact distance with the central tree on the side of the polygon and the data were summed. It was not possible to choose the best indicator, since all five were weaker than the influence of a simple power supply area. When using the feeding area at the age of 30-40 years, and then at 41-55 years, the specific pressure of neighbors varied in strength from 5.8 to 8.9%, averaging 7.4%, and when taking into account the distances to neighbors, this pressure increased to an average of 8.5%. At an average density, the strength of the trees ' cooperation was equal to 11.6%, and at a low density of 7.5%, averaging 9.6%. Thus, the cooperation of trees in the microcenosis was generally 1.13 times stronger than the competitive pressure of neighboring trees

Comparision of Voltage Stress Across the MOSFET Switch of a Flyback Converter with Various Snubbers

A Flyback converter is a simple switch-mode power supply that can be used to generate a DC output from either an AC or DC input. The converter switch is the most critical part of any converter. The voltage stress across the switch is a major issue as the high voltage spikes occur due to interaction between its output capacitance and the leakage inductance of the transformer. These spikes can be reduced with various snubbers like conventional tertiary winding, Resistor Capacitor and Diode(RCD) snubber, energy regenerative snubber and an active clamp snubber. This paper aims to analyze and compare the voltage stress across the MOSFET switch of Flyback converter with various snubber circuits.

Optical Voltammetry Closed-Cell Bipolar Electrochemistry Based Sensor for Portable Low-Cost Heavy Metal Water Testing

Events such as the ongoing Flint, MI and Newark, NJ water crises highlight the need for reliable large-scale water quality assurance. Currently available options for water testing such as laboratory analysis and commercial test strips fail to adequately provide a description of potential water issues for they are expensive, time consuming and rely on technical expertise, being practically futile for the layman and for identifying and preventing large water crisis. Our group developed a new analytical apparatus and mechanism for the detection of metals in water, which is portable, quick, accurate, cost-efficient and can be readily adapted for different deployment needs. The apparatus employs a two-step protocol of optical anodic stripping voltammetry in a readily parallelizable closed-cell bipolar electrode format and is produced under a quick and cost-effective fabrication protocol. Additionally, the fabrication utilizes readily adoptable techniques such as laser cutting as opposed to costly clean-room fabrication techniques. The tool can also be further adapted to employ other commonplace technologies such as printers and smartphones. Previous work from this lab had effectively utilized electrochemiluminescence as reporting mechanism but has now moved onto more consistent light-emitting diodes with improved linearity over several orders of magnitude, increased re-usability and limits of detection now in the sub-ppb range. This new sensing scheme utilizes a simple power supply to couple an anodic stripping event at one pole of the bipolar electrode with an LED emission which is externally recorded and processed thereby avoiding additional costly, non-portable conventional potentiostatic circuitry. In this format, near 100% faradaic efficiency can be achieved as well as facile parallelization for simultaneous sensing of multiple electroactive species. The apparatus and mechanism show great promise as a new deployable analytical tool which can be further engineered to non-electroactive species such as PFAs and to even-lower cost techniques and user-friendly protocols for unprecedented large-scale water quality assurance. Figure 1

Modeling and Motion Control of a Liquid Metal Droplet in a Fluidic Channel

As an emerging multifunctional material, Gallium-based room temperature liquid metal has attracted a lot of attention for a variety of applications due to its mobility and deformability. However, controlling the motion of a liquid metal droplet accurately still remains unrevealed, which restricts its application in many fields. In this article, we propose a hybrid framework that would control the motion of a liquid metal droplet in a one-dimensional (1-D) fluidic channel. A dynamic model of a liquid metal droplet immersed in the electrolyte when an electrical field is applied to each end of the channel is discussed first, followed by a setpoint controller designed to calculate the current input needed to drive the liquid metal droplet to its destination with vision feedback. To obtain the desired high-resolution current output, a fast and high-resolution current output power supply will be established by integrating a fast PID controller and a simple programmable dc power supply. The effectiveness of this proposed approach will be verified by controlling a liquid metal droplet so that it reaches its destination inside the polymethyl methacrylate channel. In this article, the proposed approach may lead to the development of tiny soft robots, or microfluidic systems that can be driven accurately by the liquid metal droplets.

A Simple and Compact MR-Compatible Electromagnetic Vibrotactile Stimulator.

We have developed a low-cost electromagnetic vibrotactile stimulator that uses the magnetic field of an MR scanner as a permanent magnet to power a vibrating motor. A simple variable current power supply is controlled by software using a USB data acquisition controller. In our study, the function of our novel stimulator was verified in a vibration frequency discrimination working memory task, in which various ranges of frequencies and amplitudes are delivered in MRI scanner. Furthermore, our functional MRI study revealed activations of the primary and secondary somatosensory cortices during the perception of tactile stimulation. Therefore, the new designed electromagnetic vibrotactile stimulator is capable of generating various frequencies of tactile stimuli and represents a powerful and useful tool for studying somatosensory functions with functional MRI.

Development of a substrate-invariant 2-D array of nanosecond-pulsed streamer discharges

Two dimensional arrays of streamer discharges were developed using electrical discharge machining of stainless steel sheets and stacking them together with spacers to allow gas flow between the sheets. A nanosecond pulsing circuit, capable of delivering 2–40 kV pulses with pulse widths of >20 ns by using two spark gaps as switches, was developed as a simple tunable pulsing power supply. High resolution imaging of the plasma for uniformity across the array tips was conducted. Optical emission spectroscopy was used to characterize the species created as well as probe the temperature of the discharge for various substrates, voltage pulse durations, voltage pulse magnitudes, and gas flows. The discharge properties were found to be substrate independent for a wide variety of conditions.

The impact of electrical power quality indicators on the accuracy of industrial power supply system management

The impact of power quality indicators and synchronized vector measurement device errors on electrical mode parameter assessment is examined with using a model of a simple industrial power supply system. There are underestimated requirements for the accuracy of synchronized vector measuring devices (SVMDs) with regard to their use in technical solutions designed to control the power supply modes at industrial enterprises.