DC Power Source Research Articles

A Speed Range Extension Scheme for Scalar-Controlled Open-End Winding Induction Motor Drives

This articleproposes a new control scheme for extension of speed range of dual inverter fed induction motor drives with open-end stator windings. One of the inverters connected to one end of the stator windings is fed by a dc power source whereas the inverter connected to the other end of the windings is fed by a capacitor. The control scheme ensures that only active power required by the drive is supplied by the inverter fed by dc power source and the reactive power alone is provided by the capacitor fed inverter. The modulation index of the capacitor fed inverter is varied to provide higher voltage to the motor at higher speeds keeping the capacitor voltage constant, thereby facilitating operation above base speed without field weakening. An alternative scheme in which the capacitor voltage is allowed to vary while keeping the modulation index of the capacitor fed inverter at its maximum value is also presented in this article. The proposed schemes, based on constant v/f ratio control, are simple compared to the existing schemes. Validation of the proposed schemes is carried out under transient and steady state operating conditions by extensive simulation using PLECS software. Experimental verification is also carried out on a laboratory prototype using a digital signal controller for implementation of the control scheme.

An Open-Source Low-Cost Imaging System Plug-In for Pheromone Traps Aiding Remote Insect Pest Population Monitoring in Fruit Crops

This note describes the development of a plug-in imaging system for pheromone delta traps used in pest population monitoring. The plug-in comprises an RGB imaging sensor integrated with a microcontroller unit and associated hardware for optimized power usage and data capture. The plug-in can be attached to the top of a modified delta trap to realize periodic image capture of the trap liner (17.8 cm × 17.8 cm). As configured, the captured images are stored on a microSD card with ~0.01 cm2 pixel−1 spatial resolution. The plug-in hardware is configured to conserve power, as it enters in sleep mode during idle operation. Twenty traps with plug-in units were constructed and evaluated in the 2020 field season for codling moth (Cydia pomonella) population monitoring in a research study. The units reliably captured images at daily interval over the course of two weeks with a 350 mAh DC power source. The captured images provided the temporal population dynamics of codling moths, which would otherwise be achieved through daily manual trap monitoring. The system’s build cost is about $33 per unit, and it has potential for scaling to commercial applications through Internet of Things-enabled technologies integration.

전력설비 특허 동향 분석 및 부상기술 동향에 대한 고찰

The electric power facility industry were started with all transmission and distribution devices, from power plants that produce electricity to consumers who use electricity. Major domestic power companies are concentrating on decarbonization, decentralization, digitalization, deregulation, and energy democratization as the policy direction to implement the decarbonization strategy. Although it seems a bit complicated, the reality is that the strategy of increasing the proportion of new and renewable power generation through the expansion of new and renewable business is the main issue. Therefore, as the main DC power source of renewable energy sources is connected to the transmission and distribution system, it is expected that the investment related to the safe system operation and DC facility will continue to increase. In this regard, the renewable and DC-related power facility industry is also expected to grow together. In this paper, based on patent information, the recent patent trends in the electric power facility field of IP5 countries in the United States, Europe, Japan, China, and Korea were analyzed quantitative and qualitative, respectively. The emerging technology trends were analyzed through activity and technology index analysis.

Influence of magnetron sputtering modes on the parameters of ZnO:Ga films

The aim of this work is to study the effect of magnetron sputtering modes - its technological parameters (pressure, substrate temperature and DC power source) on the morphology and electrophysical parameters of nanocrystalline ZnO:Ga films, which can be used as contact layers to nanostructures of photovoltaic converters. It was found that with an increase in the substrate temperature, the grain size decreases from 80 to 30 nm and the film surface roughness, as well as the resistivity from 1.68⋅10−1 to 1.2⋅10−2 Ω⋅cm and the mobility of charge carriers with 18.12 to 5.59 cm2/(V⋅s). In this case, the concentration of charge carriers increases from 5.59⋅1018 to 3.31 ⋅ 1020 cm−3. With an increase in the power of the DC source, the grain size increases from 35 to 90 nm and the surface roughness of the ZnO:Ga films, as well as the concentration of charge carriers from 5.91⋅1018 to 3.35⋅1020 cm−3. In this case, the resistivity decreases from 1.42⋅10−2 to 1.3⋅10−2 Ω⋅cm, and the mobility of charge carriers from 6.74 to 3.22 cm2/(V⋅s). The results obtained can be used in the development of technological processes for the manufacture of highly efficient photoelectric converters.

Analysis of cyclic voltammetry in the recovery of copper from printed circuit board waste using diluted deep eutectic solvent

Cyclic voltammetry has been successfully analyzed from a diluted deep eutectic solvent (DDES) electrolyte for recovery printed circuit boards (PCB) containing 17.91% copper. The raw material sample is made through the dismantling stage until the grinding and then sieved to 80 mesh size for testing samples. Temperature variations are used to increase the surface area of the electrodes. The temperature variations used were 40⁰C, 50⁰C, and 60⁰C. The cyclic voltammetric measurement method was carried out using the potentiostat / galvanostat autolab PGSTAT302N connected to a computer with NOVA 1.11 software and a DC power source used for electrolysis with a scan rate of 10 mV / s. From the measurement results, it was found that the largest capacitance value was at 60⁰C with an oxidation peak of 1.15 A. with a current efficiency of 99.83%. Additional testing was also carried out using SEM-EDX to see the morphological surface of the cathode used.

A Linear-Motor Type HTS Flux Pump With Pumped Current Exceeding 640 A

In this paper, we present the fabrication and performance of a linear-motor type flux pump with a pumped current larger than 640 A. This high-temperature superconducting (HTS) flux pump can be used for magnetic resonance imaging (MRI) magnets and HTS electric machines. We use the flux pump to charge 10 superconducting closed-loops, and show the tested results of pumping current under different applied frequencies and magnetic field amplitudes. This flux pump device can output direct current larger than 640 A at 77 K. The output of this flux pump equals to a DC power source with low output voltage and high output current. Comparing with the traditional power supply of the same rated current, the size of this HTS flux pump is much smaller, while it also eliminates the harmful metal current leads that cause heat leakage. We show that, by increasing the length of the travelling wave region of this flux pump, there is no limit to the output of the current output, which can reasonably reach the kilo-ampere level. The purpose of this paper is to test the reliability of the methodology for the large current HTS flux pump.

Build Charging Database of Linear-Motor Type Flux Pump and Analyze the Influence of DC-Bias Field Using Fixed Step Size Search Algorithm

The linear-motor type flux pump is a wireless DC power source for high-temperature superconducting coils, which is compact in size, efficient in energy use, fast in output control, etc. It consists of three major parts: DC windings, phase windings and iron circuit, which generates a DC-bias AC travelling wave in its airgap. In theory, there are three controllable parameters such as DC-bias field, amplitude of the AC travelling wave, and the field frequency (travelling speed). By changing those parameters, we change the applied fields and its DC output current into superconducting coils. For studying the impact of those parameters on its DC output, this paper uses a fixed step algorithm to collect the current charging data, by automatically controlling the flux pump device, and then establishes an output database. By using this algorithm, we have searched out the maximum pumped current and analyzed the impact of the three parameters. We have also found out that, in order to get maximum current output, the value of the DC-bias field should be close to the amplitude of AC magnetic field.

An Effective Energy Management With Advanced Converter and Control for a PV-Battery Storage Based Microgrid to Improve Energy Resiliency

This article presents an energy management strategy for a microgrid having solar PV arrays and a battery energy storage system (BESS). Most of the energy management strategy used for commercial photovoltaic (PV) inverters and battery inverters do not consider the future load behavior and cannot ensure the energy resiliency for a PV and battery storage based microgrid. This article proposes the use of a model predictive control strategy that considers future load behavior and energy cost profile to determine an optimum power flow trajectory to achieve energy resiliency, minimize the operating cost and maximize the profit of the microgrid. The proposed control strategy of the energy management system (EMS) is validated using both simulations in MATLAB/Simulink environment and by carrying out laboratory experiments on a developed laboratory test platform. For the converters of the test platform, this article develops a magnetically linked seven-level multilevel converter (acting as the solar PV inverter) and a full-bridge inverter with an advanced pulsewidth modulation technique (acting as the BESS inverter). Commercial inverters usually require large and bulky power frequency transformers for the grid integration of renewable energy sources. The high-frequency magnetic link-based power electronic converter can produce multiple balanced dc power sources with reduced size, ensures lower power losses during the energy conversion process and can also ensure galvanic isolation. The results from the simulation and experimental studies of the EMS demonstrate that the developed energy management strategy ensures both the minimization of the operating cost of the system and the increased resiliency of the whole system.

Design and Prototyping Single-Phase Inverter with Arduino Nano

<p class="Abstract"><span lang="EN-US">Across the year, the needs of Indonesians in the use of electronic equipment are increasing, which results in higher electricity usage. Because most of the electricity load uses AC power, in the application of a DC power source such as solar cells, an inverter that converts DC to AC power is needed. Therefore, the inverter is one of the tools that are widely developed in power electronics. The output voltage from simulation and real hardware is a sine wave with some distortion due to lack of filter; therefore, there occurs a harmonic. The voltage and frequency were also measured with a multimeter. The result shows that both voltage and frequency are closed to the design specification which is 220V 50Hz with the voltage and frequency difference of 1.09% and 0.4%, respectively.</span></p>

Proportional-Resonant Controller Structure with Finite Gain for Three-Phase Grid-Tied Converters

The paper presents the study of a three-phase system coupling a DC power source to a power grid. This study, based on an FPGA, implements a real-time control system and digital models of the power circuit. The proposed proportional–resonant (P+R) controller with a modified structure was part of the system, which can be used as an alternative controller to traditional ones, e.g., in photovoltaic systems. Due to difficulties in implementing resonant controllers, a P+R with a new structure using a PI controller was elaborated. With an appropriate approach to the generation of phase current patterns, it is possible to set the reactive current and, thus, compensate for the reactive power. The operation of the system for typical operating conditions (e.g., system startup, change in preset load) was characterized and compared with a classical solution using a PI controller.

Switched capacitor based multi-level boost inverter for smart grid applications

To link DC power sources to an AC grid, converters are needed. Inverters are the power electronic devices, which are used for this purpose. Conventional inverters employ harmonic filters and transformers that are lossy and expensive. Multilevel inverters (MLIs) are an alternative to conventional ones, proposing reduced total harmonic distortion (THD), increased range of control, and inductor-less design. They generate a stepped waveform, with close similarity to a sine wave. Many distributed sources may be employed in a smart grid. If those sources have minimal THD, the filtering process could be reduced at the point of common coupling. This paper presents two switched capacitor based MLIs, proposing boost capability and low THD. Inverters have inherent charge balancing capability, which eliminates the need for auxiliary circuits and voltage sensors. Inverters switches are modulated using phase opposition disposition pulse-width modulation (PODPWM) method that ease the balancing of the voltage and decrease the losses of switching. Designs were verified by simulation and the output waveforms were introduced.

Treatment of animals without antibiotics

The aim of our study was to develop a technology for treating animals with direct electrochemical blood oxidation. The process of direct electrochemical oxidation of blood occurs on the surface of a platinum wire electrode inserted into the blood vessel along its axis. The wire electrode is not in electrical contact with the DC power source. It is polarized by the current flowing between the additional electrodes. A solution containing a culture of staphylococci was poured into a test tube. After the passage of current through the system, staphylococci die. The cause of their death was not the electric current itself, but the products of sodium chloride electrolysis. Two chlorine atoms form a molecule that interacts with water to form an unstable hypochlorite ion, which decomposes to form atomic oxygen. Atomic oxygen is harmful to bacteria, viruses and their waste products. Positive results have also been obtained in treating dogs and calves for pneumonia.

Generation of high aspect ratio complex micro-features by micro-electrochemical milling employing novel flushing technique

Fabrication of high aspect ratio (HAR) complex micro features on high strength temperature resistant (HSTR) alloys is challenging by any conventional or non-conventional machining methods. In this study blind, HAR and complex micro features have been fabricated by micro electrochemical milling (MEM) on HSTR Cobalt alloy (Haynes-188) introducing a new strategic approach with novel flushing technique which could get rid of the need of pulsed DC power supply. Multiphysics simulation of the rotating micro-tool at different rpm and its impact on effective sludge removal has been analyzed and verified experimentally. In this study, most influencing parameters of MEM like voltage, feed rate, rpm of tool and milling layer depth have been selected to investigate their effects on the machining responses like width overcut, machined depth and surface roughness on Haynes-188 alloy. Comparison has also been made with constant and pulsed DC power source to know the influence of these process parameters on the MEM responses. Finally, several linear and non-linear blind, HAR (AR > 11) and intricate micro features have been fabricated successfully on cobalt alloy at the most suitable parametric combination, i.e., 7.5 V of machining voltage, feed rate of 0.3 mm/min, and tool rotation of 750RPM with 0.5 M of NaNO3 electrolyte.

Low Cost Noodles Making Machine

This project aims to assist people in making noodles easily, quickly and on a wider scale. The primary stage of the project with brainstorming, visualizing the thought, forecasting all our needs within the project and deeper research was held between all competitive noodle machines within the market. Proposed Noodle machine with compact Design, portable and operated by the only person. Extrusion of noodle at shaping die by endless feed of dough within the hopper which is pushed towards shaping die by thread conveyor to realize the specified shape of noodle. Design and development of noodle machine by integrating all ideas together and testing of Automatic noodle machine which is operated by DC-power source.

Microbial effect on water sorptivity and sulphate ingress by Bacillus megaterium on mortars prepared using Portland Pozzolana cement.

To determine the effect of direct embedment of Bacillus megaterium into Portland pozzolana cement mortars on water sorptivity and diffusivity coefficient of sulphate ions. Prisms with a water/cement ratio of 0·5 were prepared by blending Portland Pozzolana cement with the requisite volume of a B. megaterium (microbial) solution whose concentration was 1·0×107 cells per ml. Mortar prisms of 160mm×40mm×40mm were fabricated for this study. Mortars cured for 28days were exposed to 0·2465moll-1 Na2 SO4 solution using accelerated ion migration test method for 36-h session using a 12V DC power source. Sulphate ion concentration was then determined through the ingressed mortar at 10mm interval. A minimum water sorption gain of 0·61% was observed on the prism prepared with and cured in microbial solution. A maximum of 0·0289 and a minimum of 0·0093 water sorptivity coefficients were exhibited by the control prism and microbial prisms, respectively. The microbial prisms exhibited the lowest apparent diffusion coefficient (Dapp ) of 4·5179×10-11 m2 s-1 . Direct incorporation of B. megaterium in mortar preparation, curing or both regimes significantly retarded water sorption and lowered sulphate ion ingress. The inclusion of this bacterial in the mortar further complements the pozzolana pore structure benefits. This novel B. megaterium bacteria which can survive and cause biocementation within hydrating cement mortar when not encapsulated would result in a green innovation. Once adopted and applied in real-life scenario, it would promote construction of durable, safe, resilient and affordable shelter.

The Performance Multilevel Inverter 5 Level 1 Phase by Reducing Power Switch Components

Multilevel Inverter (MLI) is a converter that converts DC power source into AC power source with voltage output more than 2 levels. The conventional 5-level Multilevel Inverter Topology that is developing today generally uses eight power switch components. In this paper, research Topology multilevel inverter 5 levels was conducted by reducing the power switch components into four pieces and assisted by two diode clamps and capacitor as voltage coupling. PWM (Pulse Width Modulation) technique used to utilize multicarrier modulation. Simulation testing with MATLAB conducted has been verified with the results of hardware tests where the output voltage shows similarity of shape at the output voltage MLI 5 levels. The results and discussion of the proposed topology can provide economic benefits from the use of the number of power switch components (MOSFET) compared to conventional 5-level MLI topology. Keywords : Multilevel Inverter, PWM, 5 Level

Automatic Grid Switch Control between Two Electrical Sources

This paper describes about the grid switch control system. The aim of the project is to provide a facility by which we can control the two power sources in the power grid. The purpose of the project is to provide a flexible system by which we can control the two DC power sources. Now days, there is a lot of requirements to control the appliances in an industry or in a home connected to the power grid when we are working. The main aim of the present project is to provide a facility by which we can control the DC power sources connected to the power grid. The only thing is we need to switch the button for a control board to the power control section. The control board which is attached to the power grid control section in the industry. This receives the commands to the microcontroller whenever there is a power cut from the main source. The microcontroller plays a major role in receiving the commands from the main source module and to switch from a Main DC source or from a Battery DC source which is fed to thee DC generator (Wind energy). The particular source is switched according to the command. Here in this project a power grid is connected to motor control unit. The project implements the design of a system by which we can control the power grid of two DC sources.

Mathematical design and performance investigation of evaporator water cooled storage‐cum‐mobile thermoelectric refrigerator for preservation of fruits and vegetables

AbstractA storage‐cum‐mobile thermoelectric refrigeration system was designed for passive, active, and total load of refrigeration on the basis of thermo‐physical properties of polyurethane sheet, heat generated by axial fan, and internal heat of commodities stored for refrigeration. A prototype of mobile thermoelectric refrigeration system of capacity 100 L (40 kg per batch) was designed and developed for maintaining the temperature of 15 ± 2°C and relative humidity of 80 ± 5%. The developed system of dimension (45 × 50 × 50 length × width × height), composed of four thermoelectric modules, liquid cooled evaporator, axial fan, diaphragm water pump, fogger, and water tank. The system was operated by 12 V DC power source. Results obtained from experimental performance evaluation indicated that 20.8°C temperature reduction was achieved in 210 min under no load operation, whereas, 23.6°C temperature reduction was obtained in 360 min when the system was loaded with 30 kg of bitter gourd. The temperature was reduced at the rate of 9.65°C/h till temperature of 20°C was attained which latter reduced to 2.23°C/h under no load condition, whereas, rate of temperature reduction was 7.44°C/h till attainment of 20°C and then reduced to 1.43°C/h under loading condition. The techno‐economic feasibility of the system exhibited COP 0.85 which was significantly higher than those reported by several scientists in the range of 0.15–0.50. Developed refrigeration system can be effectively utilized as an eco‐friendly technology for small scale cold storage of fruits and vegetables with causing detrimental effect to environment.Practical ApplicationsDeveloped thermoelectric refrigeration technology is climate friendly without generating any global warming potential and can be commercially used for small scale cold storage of fruits and vegetables to enhance the shelf life of produce. A developed refrigeration system is helpful for fruits and vegetable vendors to maintain the quality of commodity during transportation to minimize the decay of food and fetch good value to the commodity.

Fabrication and Characterization of Non-Equilibrium Plasma-Treated PVDF Nanofiber Membrane-Based Sensors.

The effect of a self-pulsing non-equilibrium plasma discharge on piezoelectric PVDF nanofiber membrane was investigated. The plasma discharge was generated in air with a DC power source, with a discharge current of 0.012 mA, a nominal interelectrode separation of 1 mm, and discharge voltage of ~970 V. In a continuous fabrication process, the electrospinning method was used to generate thin nanofiber membrane with a flow rate of 0.7–1 mL h−1 and 25–27 kV voltage to obtain the nanofiber with high sensitivity and a higher degree of alignment and uniformity over a larger area. Plasma treatment was applied on both single layer and multi-layer (three layers) nanomembranes. In addition, simultaneously, the nanofiber membranes were heat-treated at a glass transition temperature (80–120 °C) and then underwent plasma treatment. Fourier-transform infrared (FTIR) spectroscopy showed that the area under the curve at 840 and 1272 cm−1 (β phase) increased due to the application of plasma and differential scanning calorimeter (DSC) indicated an increase in the degree of crystallinity. Finally, PVDF sensors were fabricated from the nanofibers and their piezoelectric properties were characterized. The results suggested that compared to the pristine samples the piezoelectric properties in the plasma and plasma-heat-treated sensors were enhanced by 70% and 85% respectively.

Study and Implementation of Partial Resonant High-Frequency AC-Link Inverter Operating in Soft-Switching Condition

In this paper, a high-frequency AC-link DC–AC converter is presented with detailed analysis. This converter is used as an interface between a dc power source and a grid. The studied converter is a universal power converter which consists of two bridges separated by an AC-link; each bridge is connected to a source or it feeds a load. The link of this converter contains a parallel pair inductance-capacitor. The inductance is used to stock/supply energy and for the link capacitor, it allows to perform soft switching during turning on/turning off of the switches. The studied converter has considerable advantages compared to the other topologies. Its fundamental properties are, especially, the compactness, reliability and efficiency which it ensures. Also, it guarantees longer lifetime and the possibility to transfer power in the two power flow directions. In this talk, the principles of the ac-link inverter operation are clearly explained in this paper. Simulation results, under MATLAB/SIMULINK, are shown to validate the correct operation and the efficiency of the proposed converter topology. The control algorithm is, also, experimentally implemented using a dSPACE 1104 control board.