DC Power Supply Research Articles

HiFly-Dragon: A Dragonfly Inspired Flapping Flying Robot with Modified, Resonant, Direct-Driven Flapping Mechanisms

This paper describes a dragonfly-inspired Flapping Wing Micro Air Vehicle (FW-MAV), named HiFly-Dragon. Dragonflies exhibit exceptional flight performance in nature, surpassing most of the other insects, and benefit from their abilities to independently move each of their four wings, including adjusting the flapping amplitude and the flapping amplitude offset. However, designing and fabricating a flapping robot with multi-degree-of-freedom (multi-DOF) flapping driving mechanisms under stringent size, weight, and power (SWaP) constraints poses a significant challenge. In this work, we propose a compact microrobot dragonfly with four tandem independently controllable wings, which is directly driven by four modified resonant flapping mechanisms integrated on the Printed Circuit Boards (PCBs) of the avionics. The proposed resonant flapping mechanism was tested to be able to enduringly generate 10 gf lift at a frequency of 28 Hz and an amplitude of 180° for a single wing with an external DC power supply, demonstrating the effectiveness of the resonance and durability improvement. All of the mechanical parts were integrated on two PCBs, and the robot demonstrates a substantial weight reduction. The latest prototype has a wingspan of 180 mm, a total mass of 32.97 g, and a total lift of 34 gf. The prototype achieved lifting off on a balance beam, demonstrating that the directly driven robot dragonfly is capable of overcoming self-gravity with onboard batteries.

Electroflocculation kinetics of humic acid removal from boiler make-up water using Al-base electrodes

Many coal-fired power plants have undergone a "heating transformation." This transformation measure significantly increases the boiler make-up water required by the power plant, and the make-up water source contains humic acid (HA) organic matter. HA will cause problems such as corrosion、scaling of thermal equipment and increaseing the difficulty of water treatment. The kinetics of electroflocculation were investigated in this study using an experimental device designed to treat HA from boiler make-up water, which is made of plexiglass and has a capacity of 1.2 L. The alloy plates are placed parallel to each other and perpendicular to the horizontal plane as the anode and cathode and are connected to the DC power supply through a wire. Three parameters were investigated: current density, initial pH, and electrode distance. The experimental results show that electroflocculation has a better removal effect on HA. The reaction rate constants of the three electrodes (Al–Zn–In, 6061 alloy, and Al) were 0.07994, 0.04282, and 0.03174 min−1. When the pH was 5, the current density was 100A·m−2, and the spacing between the electrodes was 3 cm, the highest rate constant of 0.10249 min−1 was observed for Al–Zn–In, and the removal rate of HA was 93.3% in 30 min. The SEM and EDS analyses were performed on the electrode and precipitated before and after electroflocculation. The doping of Al–Zn–In with In and Zn helps maintain the electrode surface's activation state during electroflocculation. The electroflocculation effect and anti-passivation ability of the three metals are Al–Zn–In＞6061 alloy＞Al. Al–Zn–In is expected to replace aluminum plates due to its resistance to passivation and superior electroflocculation effect.

Control of Self-Winding Microrobot Using an Electromagnetic Drive System: Integration of Movable Electromagnetic Coil and Permanent Magnet.

Achieving precise control over the motion position and attitude direction of magnetic microrobots remains a challenging task in the realm of microrobotics. To address this challenge, our research team has successfully implemented synchronized control of a microrobot's motion position and attitude direction through the integration of electromagnetic coils and permanent magnets. The whole drive system consists of two components. Firstly, a stepper motor propels the delta structure, altering the position of the end-mounted permanent magnet to induce microrobot movement. Secondly, a programmable DC power supply regulates the current strength in the electromagnetic coil, thereby manipulating the magnetic field direction at the end and influencing the permanent magnet's attitude, guiding the microrobot in attitude adjustments. The microrobot used for performance testing in this study was fabricated by blending E-dent400 photosensitive resin and NdFeB particles, employing a Single-Layer 4D Printing System Using Focused Light. To address the microrobot drive system's capabilities, experiments were conducted in a two-dimensional and three-dimensional track, simulating the morphology of human liver veins. The microrobot exhibited an average speed of 1.3 mm/s (movement error ± 0.5 mm). Experimental results validated the drive system's ability to achieve more precise control over the microrobot's movement position and attitude rotation. The outcomes of this study offer valuable insights for future electromagnetic drive designs and the application of microrobots in the medical field.

Automatic Material Handling System Using PLC

This paper presents the design and development of an automatic material handling system utilizing a Programmable Logic Controller (PLC) capable of efficiently managing loads up to 40 kg. The system integrates various components including Schneider PLC with corresponding data cables, proximity and photoelectric sensors with a detection distance of 4mm, servo motors operating at a speed of 60-100 RPM, a 24V DC power supply unit (input: 230V, output: 24V DC), Siemens MCB for circuit protection, Elmex connectors for terminal connections, Phoenix Contact Glass Relays operating at 230V AC, and numeric keypad push buttons with an input supply of 4-5V. The integration of these components ensures reliable operation and efficient handling of materials within the specified load capacity. This research contributes to the advancement of automated material handling systems, offering potential applications across various industries. Key Words: PLC, Ladder, Automation, HMI, Interlocking security

Performance Analysis of Positive Output (P/O) Push-Pull Switched Capacitor Converter for High Power Density Applications

The micro-power-consumption technique requires high power density DC/ DC converters and power supply sources. In this research, a PI and Fuzzy Logic Controllers for an elementary circuit of positive output (P/O) push-pull switched capacitor converter has developed for high power density applications with high sustainability under enormous line and load disturbances. The voltage lift technique is a popular application in electronic circuit design. The power converter performs DC-DC step-up voltage conversion with high efficiency, high power density and cheap topology in a simple structure. The proposed converter combines both switched-capacitor and voltage lift techniques. Referable to the time varying and switching nature of the power electronic converter their dynamic behavior becomes highly nonlinear. Conventional controllers are incapable of providing excellent dynamic performance and hence the fuzzy logic controller can be used as a feed forward controller for controlling power electronic converters. The control algorithm is developed to ensure tracking of the reference voltage and rejection of system disturbances by successive measurements of the converter output voltage at certain time instants within a conduction period. The simulation of PI and Fuzzy logic controls have been carried out using MATLAB/Simulink software to evaluate the controller’s performances. Keywords: Luo converter, DCDC converter, PI Controller, Fuzzy Controller.

An adaptive load‐matching method for the induction heating coil with DC power supply

An adaptive load‐matching method for the induction heating coil with DC power supply

Design of prototype for the short circuit protection of DC bus using Arduino Uno and DSP controller

Micro-grids (MGs) play a prominent role in the exchange of bulk power between loads and the central grid. MG can run in an islanding mode or grid-connected mode. When the central grid fails to provide power in such situations, MGs serves as power sources for critical facilities such as coordination facilities in railway stations and airports, transportation, university and research facilities. MGs use energy sources such as solar, wind, hydro, geothermal, and biomass to produce electricity along with rechargeable batteries, aircraft applications is continuously increasing. This leads to the development of DC MGs. A model of DC MG is located at the disaster management lab in the Department of Electrical and Electronics Engineering. The MG consists of step-downed and rectified DC power supply from conventional 230 V AC source, a PV array, wind, and a battery bank a source supplying power to a set of nine DC loads. Although DC MGs have many advantages compared to AC MGs, one of the challenges faced is the study of faults and protection of the DC MG. In this paper, a prototype for the existing system in the disaster management lab is designed in hardware and tested.

Novel Halbach Permanent Magnet Solenoid Design using Finite Element Method

To generate the high axial field usually Electromagnetic Coils solenoid is used but it consumes large DC power supplies and cooling system and is not compact. The PM (Permanent Magnet) solenoid on the contrary can give fixed axial field profiles that are very compact and do not require any energy source as they are themselves energy sources. PM solenoids are usually designed using large radial and axial magnetized magnets. The drawback of such a design is using large radial magnets which are often unavailable with assembly problems. The paper discusses the novel Halbach solenoid configuration design and uses ref1 solenoid results to verify it. The finite element magneto static method is used to analyze the two models. The FEM magneto static analysis was done in Magnet Infolytica FEM magneto static analysis package.

LCC-HVDC Frequency Robust Control Strategy Based on System Parameter Identification in Islanded Operation Mode

To enhance the stability of the frequency at the sending terminal of the HVDC island during operation, a novel DC supplemental frequency robust controller is proposed in this paper. The proposed controller utilizes the fast controllability of a DC power supply to maintain system frequency stability. The identification of a low-order linearized model of the system can be obtained from a high-precision Prony algorithm based on the second derivative method (SDM). Subsequently, utilizing a robust design methodology based on linear matrix inequalities, an additional frequency robust controller is devised, striking a balance between optimal performance and robustness. This supplementary frequency robust controller exhibits a straightforward control structure with a modest order, making it readily implementable. Simulation experiments conducted within the PSCAD/EMTDC framework substantiate that the designed supplemental frequency robust controller significantly enhances the frequency stability of the sending terminal system. Furthermore, when compared with traditional proportional integral (PI) controllers, it demonstrates superior control efficacy and robustness against various types of faults under different operational modes. Even in interconnected operational modes, it continues to operate effectively. The research findings offer valuable insights for practical applications in islanded power systems.

Research on Mine Wide Voltage Adaptive Power Supply

To solve the problem of multiple voltage levels and wide range of variations of underground power supply in domestic coal mines, this paper putting forward four wide power supply of adaptive design options with wide input voltage (AC 80-850 V), including phase shifted rectification based on fully controlled bridge, direct voltage adjustment based on AC power supply, voltage adjustment based on AC power supply rectification followed by chopping control, and a power supply voltage adjustment based on magnetic coupling transformer and thyristor automatic switching. After experimental comparison, the preferred scheme for automatic switching between magnetic coupling transformer and thyristors is preferred. The main circuit of this scheme adopts magnetic coupling transformer and thyristor control method, and the control circuit adopts a three way drive circuit based on MCU control, while adopting the strategy of instantaneous voltage tracking control. This scheme achieves stable operation of the output DC power supply voltage at 24V when the input AC power supply voltage varies from 80 to 850 V. The experimental results showed programme was stable and reliable, and it’s worth applying and has practical significance.

Design and Simulation of Reliability Test System of a Charging Generator

The DC voltage pulsation factor of twelve-phase rectification is much smaller than that of three- and six-phase rectification. Twelve-phase rectifier charging generators are often used where a high quality DC power supply is required. The probability of failure of charging generator is gradually increasing due to its complex structure and function. The reliability test of charging generator can provide a scientific basis for the operation condition, maintenance and determination of the repair cycle of this type of motor. The article combines the basic theory of reliability test, analyses the charging generator constant stress accelerated reliability test scheme, designs the energy feedback test drag system with the generator output as the power source of DC motor, and carries out the dynamic performance simulation and analysis of the reliability test system based on PSCAD/EMTDC. The simulation results show that the energy feedback reliability test system has fast response and good stability.

Review of Cockcroft-Walton High Voltage Low Current DC Power Supplies

High-voltage power supplies are key for developing particle accelerators, neutron generators, x-ray systems, ion implantation, etc. This paper reviews various developed voltage low current power supplies based on Cockcroft-Walton voltage multiplier circuits for accelerator-based neutron sources and other industrial and medical applications. The paper presents a detailed review of the topology of the power supply used for the high voltage generation, the key design parameters, key active and passive components used in the High Voltage (HV) system, key experimental results, protection and measurement circuit used in the power supply and about the system performance. The improvement that occurred in the size and performance of the power supplies due to the development in the technology of the magnetic components, semiconductors and energy storage devices in successive years is apparent in the discussion. Finally challenges and possible solutions for the compact design and system performance are concluded for the development of high voltage low current power supplies.

Design and Development of an Automatic Material Handling System Using PLC for 40 kg Load Capacity

This paper presents the design and development of an automatic material handling system utilizing a Programmable Logic Controller (PLC) capable of efficiently managing loads up to 40 kg. The system integrates various components including Schneider PLC with corresponding data cables, proximity and photoelectric sensors with a detection distance of 4mm, servo motors operating at a speed of 60-100 RPM, a 24V DC power supply unit (input: 230V, output: 24V DC), Siemens MCB for circuit protection, Elmex connectors for terminal connections, Phoenix Contact Glass Relays operating at 230V AC, and numeric keypad push buttons with an input supply of 4-5V. The integration of these components ensures reliable operation and efficient handling of materials within the specified load capacity. This research contributes to the advancement of automated material handling systems, offering potential applications across various industries

Automatic Star Delta Starter with an Arduino and Relays for Three Phase Induction Motor

Abstract: The most popular low voltage starters for 50 Hz industrial motors are either star or delta starters. Their purpose is to minimize the starting current that is supplied to the motor at the beginning of operation. Three contactors, a timer, and a thermal overload are typically used in the manufacturing of Star/Delta starters, which are used to run three-phase motors at 440 volts and 50 Hz AC mains supply. But in our project, we've used the same to run a\ 3-phase motor at 440-volt AC mains supply 50 Hz with a series of 12-volt DC relays, an Arduino-provided electronically adjustable timer, and a series of tiny circuit breakers. While maintaining its application for a 3-phase motor starting with a single phasing prevention, the interlocking arrangement of the relay coils and the electronic Arduino is all wired in low voltage DC of 12 Volt fed from an inbuilt DC power supply for safe handling of the starter during the study. The timer consists of an Arduino, whose output is sent to a relay to switch the mains supply from a three-phase star to a delta. Since the 3-phase motors could burn if one of the phases disappears while they are operating, the project additionally includes single-phase protection. In the case of a phase failure, the lamps' output will be switched off. In addition, the project can be improved by utilizing thyristors in a firing angle control principle to soft start the induction motor, which would eliminate all of the star delta starter's shortcomings.

Mechanical octacalcium phosphate coatings on the plasma electrolytic oxidized pure titanium for bio-implant use

In this study, OCP powder was used for mechanical coating on the plasma electrolytic oxidized (PEO) implant surface to improve bioactivity. PEO treatment was performed on the surface of the implant using a solution mixed with calcium acetate and calcium glycerophosphate, and creates porosity through a pulsed DC power supply. For compositional analysis, energy dispersive X-ray spectrometer analysis was employed to calculate OCP content and X-ray diffractometer analysis was used to confirm the crystal structure. Also, wettability, surface roughness, hardness, elastic modulus, and corrosion resistance testing were performed. Significantly, the reduction in OCP particle size decreased, and pore filling with OCP smaller particles increased as mechanical coating time increased from 0 to 12 h. Surface and cross-sectional morphology showed the presence of OCP on the substrate. Also, surface roughness, contact angles, hardness, and elastic modulus were reduced as mechanical coating time increased. Corrosion resistance was found to be the highest for mechanical OCP coating for 6 h surface treatment on the PEO-treated CW-Ti.

Electrical and electrothermal characterization of silver-coated Vectran and Amberstrand yarns for wearable heating

The development and manufacturing of conductive fibers, yarns, and fabrics is increasing exponentially due to their multiple applications in wearable electronic textiles in sensors, actuators, data processing, communication, and energy storage. This paper investigated the electrical and electrothermal properties of Liberator 40 yarns and Amberstrand 166 conductive yarns for application in wearable heating textiles. The aim of the study was to find a flexible material for protective wearable resistive heating cloths in cold environments. The analytical results demonstrate that the Liberator 40 conductive yarn gave better heating performance than the Amberstrand 166 conductive yarn due to its electrothermal characteristics. In addition, Liberator 40 conductive yarn had higher long-term durability, washing resistance, and thermal stability than Amberstrand 166 conductive yarn. The average surface temperature of both the Liberator 40 and Amberstrand 166-based wearable heating fabrics was 40°C and 34.5°C at a 9 V DC power supply, respectively. Therefore, both the conductive yarns are suitable to be applied as resistive heating elements for localized wearable heating textiles.

A modern, rapid and simple investigation of Ampère’s law

Classical physics results are often taught purely from the theoretical side. Key results, especially in electromagnetism, are typically not explored experimentally, and in applications students are then expected to leap straight into more complex scenarios that make use of these principles in electronics, sensors and instrumentation. This is unfortunate because not all individuals are equally able to learn well purely from the mathematical angle, and even those who do are not exposed to exploring the magnitude of competing effects, for example isolating a particular magnetic field signal from the background of the Earth’s field. An experiment is presented here to test Ampère’s law with a setup that can be assembled out of everyday materials with minimal components—a smartphone, a DC power supply, wires—in a procedure that can be completed in just a few hours. The data from the three magnetic field sensors of the phones, together with the gyroscope sensors providing position, are recorded and numerically integrated. The experiment is also demonstrated using sensors collected by an Arduino board instead of a smartphone. The experiment allows to measure the net current carried by wires inside the closed path over which the magnetic field is integrated, i.e. Ampère’s law. This experimental approach to exploring Ampère’s Law can be adapted towards high school or university demonstrations, depending on the level of accuracy and detail that one aims to pursue.

Tailless Information-Energy Metasurface.

Programmable metasurface technology can achieve flexible manipulations of electromagnetic waves in real time by adjusting the surface structure and material properties and has shown extraordinary potential in many fields such as wireless communications and the Internet of Things. However, most of the programmable metasurfaces have a common feature: a tail (electrical wires and DC powers), which is difficult to supply in some particular application scenarios such as canyons and mountains. To eliminate the limitation of DC power supply, the programmable metasurface and wireless power transfer technology are combined to propose a tailless information-energy metasurface (IEMS). The tailless IEMS platform can dynamically control electromagnetic waves without relying on an external DC power supply; instead, the required DC power is provided internally by the IEMS platform itself. In the tailless IEMS experiments, the concept is demonstrated through the dynamic regulation of wireless channels and the wireless transmission of DC power. This work provides a self-powered method for programmable metasurfaces, expands the application scenarios, facilitates the miniaturization of systems, and makes it easy to integrate with other systems.

Effect of Metal Oxide Semiconductor Field-Effect Transistor Output Parasitic Capacitance on Efficiency in Full-Bridge LLC DC/DC Converters.

This study analyzed the efficiency impact of a MOSFET output parasitic capacitance (Coss) on a full-bridge LLC DC/DC converter. The core of the converter was the control chip for a half-bridge LLC DC/DC converter, and the output signal of the chip controlled the first-arm power transistors of the primary side of the converter. The coupling transformer reversed the output signal to control the primary side of the second arm of the power transistor. The full-bridge converter comprises a half-bridge control chip that converts the high-voltage DC power supply to a low-voltage DC power supply, which is then synchronously rectified and supplied to the load. The primary side of the power transistor achieves a zero-voltage switching (ZVS) state through the resonance of the LLC converter. This design gives the converter high power density and a simple structure. Furthermore, to determine the appropriate output parasitic capacitance for improving converter efficiency, this study analyzed the effect of the output parasitic capacitance on the switching loss and conduction loss of the power transistor on the basis of the output parasitic capacitance of the primary-side power transistor. A 1200 W converter prototype was fabricated in this study, and when the output was 300 W, efficiency increased from 92.603% to 93.462%, a 0.859% increase. The empirical results verified the feasibility of the proposed theory.

A Compact Bandpass Filter with Active Switchable Passband Status

In order to meet the increasing demand for adjustable devices in the modern wireless communication system, a compact bandpass filter with active switchable passband is proposed. The filter is based on the half mode substrate integrated waveguide (HMSIW), and uses its cut-off characteristics to form the lower stopband. The resonant characteristics of a quarter-wavelength shorted stub generates a transmission zero (TZ) at higher frequency, which forms the upper stopband. The active control of DC power supply determines the biased states of PIN diodes to change the electrical size of the filtering parts. When the diodes are reverse biased, the filter works in C band with the passband of 3.9-5.2 GHz; when the diodes are forward biased, the passband shifts to S band of 2.7-3.6 GHz. The 28.6% relative bandwidth in both frequency bands remains constant. The simple design realizes the active switching between bands, providing a promising idea for active adjustable devices.