Voltage Power Source Research Articles

KHz Alternating Current Stable Plasma in Alcohol Aqueous Solution

Discharge in liquid has been studied in many forms and water is the mostly used liquid in those researches. In this paper, alcohol aqueous solution is used to form stable discharging. A kilo-Hz alternating current high voltage power source is used to generate plasma under the surface of liquid and the power frequency set is the range of 1~20 kilo-Hz. The voltage-current curve, optical emission spectrum and many other evidences show that the discharging in liquid is intermittent with high optic effect.

High-Performance AC Power Source by Applying Robust Stability Control Technology for Precision Material Machining

This paper presents a high-performance AC power source by applying robust stability control technology for precision material machining (PMM). The proposed technology associates the benefits of finite-time convergent sliding function (FTCSF) and firefly optimization algorithm (FOA). The FTCSF maintains the robustness of conventional sliding mode, and simultaneously speeds up the convergence speed of the system state. Unfortunately, when a highly nonlinear loading is applied, the chatter will occur. The chatter results in high total harmonic distortion (THD) output voltage of AC power source, and even deteriorates the stability of PMM. The FOA is therefore used to remove the chatter, and the FTCSF still preserves finite system-state convergence time. By combining FTCSF with FOA, the AC power source of PMM can yield good steady-state and transient performance. Experimental results are performed in support of the proposed technology.

A new autostabilization mechanism in the Bennet doubler circuit-based electrostatic vibrational energy harvester

In this work, the theoretical and experimental study of the electric circuit is carried out for the electrostatic microgenerators based on the Bennet doubler with a power source in a variable capacitor branch. It is established that the circuit is able to operate at different capacitance modulation depth values. For the circuit with one variable capacitor, when the maximal-to-minimal capacitance ratio is less than 2, one can observe a saturation of the storage capacitor voltage (voltage autostabilization process). The equation for the saturation voltage evaluation is derived. As it is revealed for a maximal-to-minimal capacitance ratio more than 1.5, the saturation voltage is higher than power source voltage V0. When the maximal-to-minimal capacitance ratio is greater than 2, one can observe a continuous growth of the capacitor voltages as for the basic Bennet doubler conditioning circuit. A similar change of the regimes in the same circuit, but with two variable capacitors, takes place when a maximal-to-minimal capacitance ratio is about 1.618. The employment of the considered Bennet doubler conditioning circuit enables solving two main problems: operation only for a capacitance modulation depth above 2 (1.618) and the uncontrolled capacitors voltages growth. The circuit under study can be also used for electret microgenerators and for microgenerators based on using electrodes with materials having different work functions.

Entangled γ-photons—classical laboratory exercise with modern detectors

This paper describes the application of modern semiconductor detectors of γ and β radiation, which can be used in undergraduate laboratory experiments and lecture demonstrations as a replacement for Geiger–Müller (GM) tubes. Unlike GM tubes, semiconductor detectors do not require a high voltage power source or shaping circuits. The principle of operation of semiconductor detectors is discussed briefly, and classical experiments from nuclear physics are described, ranging from the measurements of linear and mass attenuation coefficient to a demonstration of entangled γ-photons.

Tuning Electrode Properties and Surface Contacts for Uniform Deposits Produced by Atmospheric Plasma Dielectric Barrier Discharge Reactors

An investigation of the effect of experimental parameters on the temperature and uniformity of material deposition by atmospheric pressure dielectric barrier discharge (DBD) planar plasma reactors was conducted. The apparatus consisted of a pulsed AC high voltage power source with various electrode materials (aluminum, copper wire mesh, and aluminum/copper wire mesh) operating under a range of load resistances. Possible effects of non-ideal interfacial conditions for the contact surface between the electrode and the substrate were also studied with various modified surface thermal conditions. It was found that a hybrid electrode design with a fine copper (Cu) wire mesh attached to an aluminum plate of approximately 3 mm thickness produced the most visually uniform deposit, presumably as a result of both the superior conductivity provided by the Al metal plate and the stable plasma resulting from the relatively low breakdown voltage by using helium (He) as the dilution gas. Although the experimental conditions of plasma-enhanced chemical vapor deposition (PECVD) are often specific to particular systems and applications, this work provides insights on technical details which can be applied to various plasma DBD reactors.

Comparative Study of PMSG Controllers for Variable Wind Turbine Power Optimization

With a large increase in wind power generation, the direct driven Permanent Magnet Synchronous Generator is the most promising technology for variable speed operation and it also fulfills the grid requirements with high efficiency. This paper studies and compares conventional based on PI controller and proposed control technique for a direct driven PMSG wind turbine. The generator model is established in the Park synchronous rotating d-q reference frame. To achieve maximum power capture, the aeroturbine is controlled through Maximum Power Point Tracking (MPPT) while the PMSG control is treated through field orientation where the two currents control loops are regulated. A proposed direct-current based d-q vector control design is designed by the integration of the Internal Model Controller. Then an optimal control is developed for integrated control of PMSG power optimization and Voltage Source Converter control. The design system was done using SimWindFarm Matlab/Simulink toolbox to evaluate the performance of conventional and proposed technique control of PMSG wind turbine. The analysis, simulation results prove the effectiveness and robustness of the proposed control strategy.

Многоканальное преобразование постоянного напряжения в трехфазное квазисинусоидальное напряжение

In synthesizing a high-capacity three-phase voltage inverter (TVI) with multichannel conversion of power flow, it is proposed to use an energy-saving algorithm for control of its output voltage, which shapes the voltage waveform by means of pulse-amplitude modulation (PAM). Such TVI version is denoted as M-TVI with pulse-amplitude modulation. It is shown based on the comparative analysis results that in comparison with an М-TVI of the same class but with the conventional PWM-based algorithm for shaping the output voltage, the energy-saving control algorithm features lower values of power supply quantization levels and the minimal number of power switch switching operations. This also results in a lower level of generated interference, lower wear and longer service life of electrical machine winding insulation, smaller level of dynamic losses in the switches, and higher power source voltage utilization factor. The investigation was carried out with the use of Fourier series and computer simulation. The preferred application field of M-TVIs with PAM is using them for controlled AC motors of increased power capacity.

A Bipolar Half-Sine Current Inverter for Airship-Borne Electromagnetic (AEM) Surveying

A topology of a bipolar half-sine current inverter for geophysical airship-borne transient electromagnetic (EM) surveying is developed. In detail, the RLC series resonance inverter with novelty is designed and analyzed. The key parameters of the output current with very small overshoots and high current amplitude are calculated and simulated, respectively. The results of calculation and simulation agree well with each other. The circuit design and principle analysis of the converter are described clearly. The main reason we choose series resonance current inverter rather than the more common parallel one is that a low-voltage source, such as a standard 28-V dc voltage of the usual aircraft power source, could realize high peak current output through a transient series resonance process efficiently. The proposed current inverter is successfully implemented to the airship-mounted geophysical surveying systems. It achieves a substantial improvement of performance and provides an alternative for the traditional fixed-wing EM systems or helicopter EM systems with much lower cost and higher efficiency. Besides, the experimental results for explorations demonstrate that the measured magnetic field of three axes also agrees well with application requirements of airship-borne EM system.

DIAGNOSTIC OF THE INSULATION STATE OF THE ASYNCHRONOUS MOTOR AND THE POWER SUPPLY CABLE UNDER CONDITIONS OF LOCAL COMPENSATION

More than 70 % of the load in metallurgy, mining, gas, and other industries of the CIS consist of asynchronous motors. A relevant objective for all enterprises is to reduce consumption of reactive power in the network and ensuring reliable start of the engine by controlling the resistance value of the insulation. The most effective measure for reactive power compensation is placing the capacitor batteries directly at the points of connection of the asynchronous motor i. e. local reactive power compensation. The aim of the present research was to reduce the cost of production of the enterprise (which provides reactive power compensation), and in the period of technological pause to use the power stored in the capacitor to batteries in order control the changes of resistance value of insulation. After disconnecting the motor from the mains and its stop, the windings is being connected in parallel to the capacitor bank. The discharge of the capacitor is performed in the circuit consisting of the inductance of the motor winding, the integrated insulation resistance and battery capacity. Characteristic features of the transitional discharge process of the capacitor depend on the size of the equivalent circuit elements. The transition process may be aperiodic and periodic in its nature. Aging of motor winding causes a decrease of its impedance. When the magnitude of the insulation resistance reaches a critical value, this causes a change of the nature of the process. The device that has been developed monitors the insulation condition of the motor and the power supply cable during technological pauses without the low voltage power source and additional switching.

Atmospheric non-thermal argon–oxygen plasma for sunflower seedling growth improvement

Seedling growth enhancement of sunflower seeds by DC atmospheric non-thermal Ar–O2 plasma has been proposed. The plasma reactor was simply designed by the composition of multi-pin electrodes bonded on a solderable printed circuit board (PCB) anode. A stable plasma was exhibited in the non-periodical self-pulsing discharge mode during the seed treatment. The experimental results showed that non-thermal plasma treatment had a significant positive effect on the sunflower seeds. Ar–O2 mixed gas ratio, treatment time and power source voltage are the important parameters affecting growth stimulation of sunflower sprouts. In this research, the sunflower seeds treated with liters per minute (LPM) of Ar–O2 plasma at a source voltage of 8 kV for 1 min showed the best results in stimulating the seedling growth. The results in this case showed that the dry weight and average shoot length of the sunflower sprouts were 1.79 and 2.69 times higher and heavier than those of the untreated seeds, respectively.

Implementation and Performance Analysis of Small Scale Integrated Circuit Test System Based On PMU

A design method of small integrated circuit test system based on precise measurement unit is presented in this paper, and the small power range is verified in detail. The test system the voltage/current clamp technique, comparison of technology, power expansion constant current source and voltage source and four quadrant drive technology, the combination of technology, to the device under test (DUT) applied to precisely and accurately measure the DUT value of the incentive, incentive in the response of the system at the same time. With high power capacity expansion to meet the various needs of the test circuit. The four channel system with integrated instrument amplifier circuit, combining extension circuit and PC control interface to accomplish the design of embedded controller, power, solve the nA current cannot be accurately measured, by optimizing the compensation circuit design, improve the testing speed of circuit. The analysis results show that the performance of the system, integrated circuit test system in the design of high precision, stable and reliable excitation and fast response speed, cost saving compared to 2/3 hardware design of similar products, to meet the integrated circuit DC parameter test requirements.

A Numerical Matrix-Based Method for Stability and Power Quality Studies Based on Harmonic Transfer Functions

Some couplings exist between the positive- and negative-sequence impedances of a voltage-sourced power converter especially in the low frequency range due to the nonlinearities and low-bandwidth control loops such as the phase-locked loop. In this paper, a new numerical method based on the harmonic transfer function for analysis of the linear time periodic systems is presented, which is able to handle these couplings. In a balanced three-phase system, there is only one coupling term, but in an unbalanced (asymmetrical) system, there are more couplings, and therefore, in order to study the interactions between these couplings a matrix-based method should be used. No information about the structure of the converter is needed and elements are modeled as black boxes with known terminal characteristics. The proposed method is applicable for both power quality (harmonic and interharmonic emissions) and stability studies, which is verified by simulations in this paper.

Realization of an SI traceable small force of 10 to 100 micro-Newton using an electrostatic measuring system

<p><span lang="EN-US">A small force of (10</span><span lang="EN-US">–</span><span lang="EN-US">100) micro-Newton traceable to the International System of Units (SI) has been realized using</span><span lang="EN-US"> an</span><span lang="EN-US"> electrostatic </span><span lang="EN-US">measuring system</span><span lang="EN-US"> at the National Institute of Metrology, China. The key component of the measuring system is a pair of coaxial cylindrical electrodes. The inner electrode is suspended with the support of a self-balanced flexure hinge, while the outer electrode is attached to a piezoelectric moving stage. The stiffness of the self-balanced flexure hinge was also designed so as to be both sufficiently stable and sensitive to the small force applied to the inner electrode. Two sets of cameras were </span><span lang="EN-US">used</span><span lang="EN-US"> to capture the shape of the electrodes and to obtain a better coaxial arrangement of the inner and outer electrodes. With the help of a capacitance bridge and a piezoelectric moving stage, the relative standard uncertainty of the capacitance gradient does not exceed 0.04 %. Associated with a laser interferometer and a DC voltage power source, the feedback system that controls the position of the inner electrode is responsible for the generation of a force of 10–100 micro-Newton. The standard uncertainty associated with the force of 100 micro-Newton does not exceed 0.1 %.</span></p>

Study on Discharge Dynamics in an Atmospheric Pressure Dielectric Barrier Discharge

In this work, the discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor having parallel plate electrodes geometry. The DBD reactor is powered by a 50 Hz ac high voltage power source through a ballast resistor. The images of filaments occurring in the discharge gap are captured using a high speed intensified charge coupled device camera. The occurrence of frequent synchronous breakdown of micro discharges has been observed across the discharge gap when the electron avalanche happens in the direction from the dielectric surface towards the opposite electrode. The discharge gap dependence on synchronous breakdown is studied by changing the discharge gap. The shape of the filaments has been found to be strongly dependent on the direction of the electron avalanche. It is demonstrated that the diffusion of electrons occurs when the electron avalanche happens in the direction towards the dielectric from the opposite electrode. A smaller diffusion leading to narrower filaments is observed when the electron avalanche happens in the direction from the dielectric to the opposite electrode. This can be explained by the existence of memory charge on the dielectric surface.

Methods to improve harvested energy and conversion efficiency of viscoelastic dielectric elastomer generators

As a new transduction technology, dielectric elastomer generators (DEGs) are capable of converting mechanical energy from diverse sources into electrical energy. However, their energy harvesting performance is strongly affected by the material viscoelasticity. Based on the finite-deformation viscoelasticity theory and the nonlinear coupled field theory for dielectric elastomers, this work presents a theoretical framework to model the performance of DEGs. Motivated by the recent experiments of DEGs with a triangular harvesting scheme, we propose a method to optimize the harvesting cycle, which could significantly improve the conversion efficiency of viscoelastic DEGs. From our simulation results, choosing a higher voltage power source appears to be an effective way to improve the performance of DEGs. In addition, optimizing the period of the discharging process of DEG can markedly increase its efficiency. Also, we have uncovered that the triangular harvesting scheme for DEGs, which is expected to harvest energy close to the maximum achievable energy, could be actually realized by choosing dielectric elastomers with a higher fraction of time-independent polymer networks. The theoretical framework and simulation results presented in this work are expected to benefit the optimal design of DEGs for different applications.

Online learning control for harmonics reduction based on current controlled voltage source power inverters

Nonlinear loads in the power distribution system cause non-sinusoidal currents and voltages with harmonic components. Shunt active filters U+0028 SAF U+0029 with current controlled voltage source inverters U+0028 CCVSI U+0029 are usually used to obtain balanced and sinusoidal source currents by injecting compensation currents. However, CCVSI with traditional controllers have a limited transient and steady state performance. In this paper, we propose an adaptive dynamic programming U+0028 ADP U+0029 controller with online learning capability to improve transient response and harmonics. The proposed controller works alongside existing proportional integral U+0028 PI U+0029 controllers to efficiently track the reference currents in the d-q domain. It can generate adaptive control actions to compensate the PI controller. The proposed system was simulated under different nonlinear U+0028 three-phase full wave rectifier U+0029 load conditions. The performance of the proposed approach was compared with the traditional approach. We have also included the simulation results without connecting the traditional PI control based power inverter for reference comparison. The online learning based ADP controller not only reduced average total harmonic distortion by 18.41 U+0025, but also outperformed traditional PI controllers during transients.

Power Stabilization Strategy of Random Access Loads in Electric Vehicles Wireless Charging System at Traffic Lights

An opportunity wireless charging system for electric vehicles when they stop and wait at traffic lights is proposed in this paper. In order to solve the serious power fluctuation caused by random access loads, this study presents a power stabilization strategy based on counting the number of electric vehicles in a designated area, including counting method, power source voltage adjustment strategy and choice of counting points. Firstly, the circuit model of a wireless power system with multi-loads is built and the equation of each load is obtained. Secondly, after the counting method of electric vehicles is stated, the voltage adjustment strategy, based on the number of electric vehicles when the system is at a steady state, is set out. Then, the counting points are chosen according to power curves when the voltage adjustment strategy is adopted. Finally, an experimental prototype is implemented to verify the power stabilization strategy. The experimental results show that, with the application of this strategy, the charging power is stabilized with the fluctuation of no more than 5% when loads access randomly.

Sliding-mode control of single input multiple output DC-DC converter.

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

Recent Patents on Electrospinning Machine

Background: Electrospinning technology is a simple and effective method for the production of polymer nanofibers. The electrospinning machine is the carrier of the spinning process, mainly includes high power voltage source, generating device and collecting device. Objective: To meet the increasing requirement of spinning parameters and efficiency, the mechanical structure of the machine is constantly being improved. Method: This paper reviews various representative patents related to electrospinning machine. Results: The differences of different types electrospinning machines are compared and analyzed and the characteristics are concluded. The main problems in its development are analyzed, the development trend is foreseen, and the current and future developments of the patents on electrospinning machine are discussed. Conclusion: The optimization of the electrospinning machine structure improves the efficiency of spinning and the electrospinning condition. For further enhancement, more patents on electrospinning machine should be invented. Keywords: Centrifugal, electrospinning machine, electrospinning principle, mechanical structure, multi spinnerets, nanofibers.

Digital current control in a rotating reference frame - Part I: System modeling and the discrete time-domain current controller with improved decoupling capabilities

Digital current control of three-phase voltage-source power electronic converters is analyzed. Special attention is paid to the exact discrete time-domain modeling of inductive-resistive current dynamics in the rotating reference frame whereas three different regular sampling strategies are incorporated to the analysis. The exact system model motivates the development of a new current control structure in the rotating reference frame that is based on discrete time-domain analysis. Ideally, the new discrete time-domain current controller leads to a full compensation of all cross-coupling effects that appear in the controlled system. The experimental results (performed on a 22 kW test-bench) reveal that even under test conditions an excellent decoupling capability of the presented controllers is achieved.