AC Power Supply Research Articles

Transfer of a cold atmospheric pressure plasma jet through a long flexible plastic tube

This work proposes an experimental configuration for the generation of a cold atmospheric pressure plasma jet at the downstream end of a long flexible plastic tube. The device consists of a cylindrical dielectric chamber where an insulated metal rod that serves as high-voltage electrode is inserted. The chamber is connected to a long (up to 4 m) commercial flexible plastic tube, equipped with a thin floating Cu wire. The wire penetrates a few mm inside the discharge chamber, passes freely (with no special support) along the plastic tube and terminates a few millimeters before the tube end. The system is flushed with Ar and the dielectric barrier discharge (DBD) is ignited inside the dielectric chamber by a low frequency ac power supply. The gas flow is guided by the plastic tube while the metal wire, when in contact with the plasma inside the DBD reactor, acquires plasma potential. There is no discharge inside the plastic tube, however an Ar plasma jet can be extracted from the downstream tube end. The jet obtained by this method is cold enough to be put in direct contact with human skin without an electric shock. Therefore, by using this approach an Ar plasma jet can be generated at the tip of a long plastic tube far from the high-voltage discharge region, which provides the safe operation conditions and device flexibility required for medical treatment.

Time-resolved spectra of solar simulators employing metal halide and xenon arc lamps

The time-resolved spectra of the irradiation emitted from solar simulators employing the two types of high-intensity discharge arc lamps that are commonly used in solar simulators, i.e. metal halide (here 6kW) and xenon arc (here 5kW) lamps, are reported. The lamp emission was recorded by a fast-response photodiode, which reveals that the amplitude of oscillating irradiation intensity from the metal halide lamp is approximately 60% of the peak intensity, while its oscillation frequency is twice of the frequency of the AC power supply, here 100Hz. The irradiation of the xenon arc lamp is powered by a modulated DC supply to oscillate at 300Hz, with an amplitude that is found to be only approximately 9% that of the peak intensity. An intensified CCD camera, which was coupled with a spectrometer operating in a range of 350–900nm, was synchronized with the lamp to provide phase-resolved spectra. The irradiation from the xenon arc lamp was found to be spectrally stable with time; while that from the metal halide lamp varies significantly throughout oscillation cycle, especially at the shorter-wavelengths of below 550nm. All spectra were calibrated to reveal that the time-averaged spectrum of the simulator with a metal halide lamp matches the solar spectrum significantly better than does that from a xenon arc lamp. The reflecting surface of polished ellipsoidal reflector was found to reduce the intensity of selected frequency bands by up to 10%, while that from both the polished ellipsoidal reflector and conical concentrator was found to reduce the intensity in selected frequency bands by up to 20%.

IJIREEICE - Electrical, Electronics, Instrumentation and Control

4 Abstract: Adiabatic logic is commonly used to reduce the loss during the charging and discharging process of circuit operation. Adiabatic logic is also known as energy or logic. The adiabatic logic uses AC power supply instead of constant DC supply.This is one of the main reasons in the reduction of power dissipation. This paper describes implementation full subtractor. The simulation results of CMOS design are compared with different adiabatic logic styles such as efficient charge recovery logic (ECRL) and positive feedback adiabatic logic (PFAL).The simulation results indicate that the proposed technique is advantageous in many of the low power digital applications. The design is implemented using Tanner tool.

Inactivation of <italic>Candida albicans</italic> by Cold Atmospheric Pressure Plasma Jet

Nonthermal atmospheric pressure plasma jets (APPJs) are characterized by very reactive chemistry without the need of elevated temperatures. Also, plasma jets are capable of producing cold plasma plumes that are not spatially confined by electrodes, which makes them very attractive for biomedical applications. In this paper, we investigate the antimicrobial efficiency of a simple plasma jet device operating with pure He as working gas. The device was driven by an ac power supply operated at 31.0 kHz, 13.0 kV amplitude with mean power around 1.8 W. The jet was directed perpendicularly on a standard Petri dish (Ø90 mm × 15 mm) filled with agar. The jet fungicidal efficiency was tested against Candida albicans (reference strains SC 5314 and ATCC 18804) and five clinical isolates from previously obtained denture stomatitis lesions. In this paper, the effects of treatment time and distance to the target were evaluated. In most treatments the samples did not have direct contact with the plasma plume; therefore, the reactive oxygen species produced by interaction between the plasma jet and ambient air were the principal inactivate agent.

Corrosion resistance in simulated DMFC environment of plasma electrolytic oxidation coating prepared on aluminum alloy

This paper aims to provide a novel substrate for the fabrication of micro passive direct methanol fuel cells. Aluminum alloy treated by plasma electrolytic oxidation (PEO) is electrically non-conductive and corrosion resistant, and thus it can act as the substrate materials of fuel cells. For this application, the corrosion problem of PEO coating in DMFC electrolytic environment that mainly contains H+ and F− must be seriously handled for that the corrosive products can poison catalyst and decrease proton conductivity. In this paper, PEO coating was prepared on aluminum alloy LY12 by an AC power supply in sodium silicate, and its corrosion resistance in the simulated DMFC environment was evaluated by potentiodynamic scan and EIS. The results indicate that the PEO coating shows excellent corrosion resistance in the simulated DMFC environment.

An Application of Two-Phase Resonant Inverter System to Generate Rotating Magnetic Field for Plasma Instability Control in a Tokamak

Rotating magnetic field (RMF), which interacts with plasma through electromagnetic force, is increasingly used for plasma instability control in magnetic confinement fusion experiment devices. In general, energizing magnetic field coils to obtain the desired RMF requires multiphase currents with an amplitude of up to several kiloamperes at a frequency ranging from a hundred hertz to several kilohertz. In this paper, we propose a two-phase ac power supply (ACPS) system based on full-bridge resonant inverters as an extension of the application of multiphase resonant converters. A novel phase control scheme for the two-phase resonant inverter system using a digital phase-locked loop is also proposed to synthesize RMF with enough spectral purity. The completed power system consists of two units. Each unit can supply a load with a rated output power of 1200 kW and a sinusoidal current in the frequency range of 1-5 kHz. The proposed ACPS can effectively cope with the physical requirements.

Comparative analysis of swarm optimization-based control method for direct matrix converter

Direct matrix converter (DMC) is an AC–AC converter which supplies power flow between AC power supply and the load for changing voltage and current requirements. Its relatively small power circuits and simple control structures provide considerable advantages to itself with respect to the classical AC–AC converter topologies. In this article, the new control method based on swarm optimization is suggested and analyzed comparatively for 3-phase DMC to improve the robustness of DMC control system. The switching generator designed with this control method generates optimal switching states using swarm intelligence-based optimization algorithm and also applies them to the DMC. To compare the control performance of the method for this type of operating conditions, chaotic-based particle swarm optimization and artificial bee colony algorithms are used since their relatively short program codes and superior optimization performances. The results of this study show that the proposed control method can be applied to the DMC control system successfully as a new control technique.

双方向性トリガーダイオードを用い生成した低気圧円筒形誘電体バリア放電動作特性解析

This paper describes the fundamental characteristics of dielectric barrier discharges (DBD) generated using high-voltage silicon diode for alternating current (SIDAC). Use of the high-voltage SIDACs with a conventional ac power supply could offer the stepped change in the output high-voltage due to high-speed switching of the SIDACs. Such the stepped high-voltage operation can easily establish DBDs with low cost instead of rf power sources and the pulse voltage power sources usually used for DBDs. The DBDs sustained by the SIDAC with the ac power supply were fundamentally studied in terms of the voltage-current characteristics of generated DBDs. Finally, three types of discharge mode were found to be categorized in the DBDs operation.

商用交流電源により直接駆動可能な単相SRMの提案と実機特性

This paper presents a novel single-phase switched reluctance motor (SRM) that can be directly driven by a commercial AC power supply without any switching circuit and sensor. This proposed SRM is optimized based on a simple design technique. The optimized machine has higher motor efficiency compared with conventional induction motors. In addition, the novel SRM can start-up with direct commercial AC power supply. In this paper, the performance of the prototype single-phase SRM is verified through simulations and experiments.

Self-organized pattern formation of an atmospheric-pressure, ac glow discharge with an electrolyte electrode

An atmospheric-pressure plasma sustained by an ac power supply was generated using electrolyte solution as one of the electrodes. By altering the power supply, ring-like patterns, double-ring patterns and plasma-spot patterns were observed at the electrolyte–electrode surface. Synchronous current–voltage characteristics and time-resolved images were measured. Important factors for the self-organized patterns, including the electrode gap, power, frequency and electrolyte concentration, were explored. The optical spectrum characteristics of the device were investigated. The pH of the solution after discharge was also explored and the results show that the pH of the solution is evidently reduced after the discharge, implying that acidic components are produced in the solution. This study provides an alternative discharge method for producing patterns on a water surface.

Effect of dielectric wall temperature on plasma plume in an argon atmospheric pressure discharge

In this letter, the effect of the dielectric wall temperature on the length and volume of an atmospheric pressure plasma jet (APPJ) is investigated using a single-electrode configuration driven with an AC power supply. To distinguish the APPJ status from the argon flow rate, the three modes, laminar, transition, and turbulent, are separated. When the dielectric wall is heated, the APPJ length and volume are enhanced. Also, the transition regions remarkably expand over a large range of flow rates. The results indicate that different factors contribute to the expansion of the transition region. The increase in the radial and axial velocities is the main cause of the expansion of the transition region to the low-velocity region. The expansion to the high-velocity region is dominantly induced by a change in the viscosity.

Effect of Pulse Rise time on Plasma Plume Propagation Velocity

Atmospheric pressure plasma jets driven by a pulsed dc power supply have several advantages over the traditional jets driven by an ac power supply. However, how the pulse rise time affects the characteristic of the plasma jets is not clearly known. In this paper, the simulation results of a plasma jet driven by pulsed dc voltages with different pulse rise time trise are presented. It shows that, the shorter the pulse rise time trise is, the faster the head of the plasma jet propagates.

A Single-Phase AC Power Supply Based on Modified Quasi-Z-Source Inverter

This paper presents a single-phase ac power supply circuit that based on modified voltage-fed quasi-Z-source inverter topology; it suits to the light or the heavy load and is fit for the resistive, inductive, or capacitive load. The topology, operating principle, voltage gain, control method, and its realization by DSP are described in this paper. The feasibility and rationality of the system is verified by the simulation and experimental results.

Experimental Study on the Pattern Structure of a Boundaryless, 1-D Dielectric Barrier Discharges Using a Ring Electrode

A symmetrical 1-D self-organized discharge pattern is formed in argon near atmospheric pressure. The electrode is shaped as a circular configuration with a wedge-shaped brim and driven by an ac power supply operating at a frequency of 30 kHz. In this circular electrode configuration, each discharge channel of the pattern is accompanied by two neighboring discharge channels on both sides identically, therefore the pattern structure is simplified and its symmetry is advanced. The presented photos exhibit the regularly developing symmetrical patterns with the applied voltage.

The Simulation Research of 5KVA/400Hz Medium Frequency Power Supply in Matlab/Simulink

This paper built 5 KVA / 400 Hz medium frequency power supply AC - DC - AC main circuit, Output filter is designed in detail. Based on SPWM control strategy and the voltage RMS feedback loop and PI adjustment, the Matlab/Simulink simulation model is established, and Harmonics are analyzed, the conclusion is obtained.

Distortion-Free CV/CC AC Power Supply Having the Unity Input Power Factor by the Use of Variable Capacitance Devices

A new CV (Constant-Voltage) CC (Constant-Current) ac power regulator is proposed. Our original Variable Capacitance Device of linear reactance device is utilized in the power stage. This device makes almost no distortion. In this circuit, a sinusoidal output voltage and a high efficiency can be obtained. For the purpose of output voltage/current control and input power-factor correction, two Variable Capacitance Devices were adopted. Two dc-dc converters were used for high-speed driver of these devices. The unity input power factor can be obtained all over the constant-voltage region and the constant-current region. Input current of the proposed power supply becomes almost zero at no load and at short-circuit load.

Research and Application of PV Intelligent Control System of Sustainable Supply

As the primary energy consumption and environmental pollution increasing seriously, green energy has been more and more got attention of researchers both at home and abroad, especially the study of solar occupies a large proportion in the development of green energy. The photovoltaic (PV) power supply system has many advantages, however, there are still problems, e.g. low voltage, low power, poor ability to resist disturbance. Around these problems, the paper designed a PV power supply control system could realize the uninterrupted power supply, including DC and AC supply. By the method of combining software with hardware, through the solar panel to the configured two pieces of battery could realize the function of fast and float charging, and the supply battery is changed by testing the battery power to load uninterrupted power supply. Moreover, when the output voltage of the solar panel is lower than the battery, the output voltage of solar panel is boosted by DC/DC circuit to make the solar panel at low pressures also to charge the battery, effectively solving the difficult solar energy in the weak power supply problem. Finally, the design of PV power supply control system not only could realize DC supply, and also AC power supply by SPWM method, which has good effect of power supply.

Safety evaluation of small-break LOCA with various locations and sizes for SMART adopting fully passive safety system using MARS code

A safety evaluation of SMART adopting a fully passive safety system was performed for a small-break loss of coolant accident (SBLOCA) with various break locations and sizes using the MARS code. It is necessary for SMART, adopting a fully passive safety system composed of passive safety injection system (PSIS), automatic depressurization system (ADS), and passive residual heat removal system (PRHRS), to satisfy the passive safety performance requirements, i.e., the capability to maintain safe shutdown conditions for a minimum of 72h without AC power supply or operator action in the case of a design basis accident. A number of SBLOCAs of different locations and sizes were analyzed using the MARS code. The results of the break spectrum analyses showed that the collapsed liquid level inside the core support barrel is maintained high enough above the top of the core owing to the sufficient passive safety injection flow from the core makeup tank (CMT) and safety injection tank (SIT). Therefore, the core is not uncovered for 72h after the break without AC power supply or operator action, resulting in a continuous decrease of fuel cladding temperature throughout the transient.

Prediction of temperature and water level in a spent fuel pit during loss of all AC power supplies

A prediction method for water temperature in a spent fuel pit of a pressurized water reactor (PWR) has been developed to calculate the increase in water temperature during the shutdown of cooling systems. In this study, the prediction method was extended to calculate the water level in a spent fuel pit during loss of all AC power supplies, and predicted results were compared with measured values of spent fuel pools in the Fukushima Daiichi Nuclear Power Station. The calculations gave reasonable results, but overestimated the decreasing rate of the water level and the water temperature. This indicated that decay heat was overestimated and evaporation heat transfer from the water surface was underestimated. Results of calculations with 80% decay heat and 155% (Unit 4 pool) or 230% (Unit 2 pool) evaporation heat flux were in good agreement with measured values. The data-fitted evaporation heat fluxes agreed rather well with the evaporation heat transfer correlation proposed by Fujii et al.

A CIRCUIT SIMPLIFICATION FOR AC POWER SUPPLY SPD

An attempt is made for simplifying the circuit structure of the surge protective device (SPD) installed on single-phase AC power supply lines of electronic systems. In the light of the drawback of the traditional circuit, a simplified circuit is proposed. The simplified circuit can substantially reduce the number of the protective components and the size of the SPD chassis. In order to compare the protective performances between the traditional and simplified circuits, an impulse experimental arrangement is built to measure their residual voltages. The measured results show that the voltage protection level of the simplified circuit is the same as that of the traditional circuit. Therefore, replacement of the traditional circuit by the simplified circuit is really feasible in lightning overvoltage protection of AC power supplies of electronic systems.