Output Voltage Characteristics Research Articles

A High-Resolution MEMS Piezoelectric Strain Sensor for Structural Vibration Detection

This paper presents the modeling, fabrication, and testing of a high-performance dynamic strain sensor. Using microelectromechanical systems (MEMS) technology, ZnO piezoelectric microsensors are directly fabricated on silicon and steel substrates. The sensors are intended to be used as point sensors for vibration sensing without putting an extra burden on the host structures. A model that incorporates piezoelectric effects into an RC circuit, representing the sensor architecture, is developed to describe the voltage output characteristics of the piezoelectric microsensors. It is shown that the sensitivity of microplanar piezoelectric sensors that utilize the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sub> effect is linearly proportional to sensor thickness but unrelated to sensor area. Sensor characterization was performed on a cantilever beam cut from a fabricated silicon wafer. The experimental data indicate that the overall sensor and circuit system is capable of resolving better than 40.3 nanostrain time domain signal at frequencies above 2 kHz. The corresponding noise floor is lower than 200 femto-strain per root hertz and the sensitivity, defined as the sensor voltage output over strain input, is calculated to be 340 V/epsiv . Micro ZnO piezoelectric sensors fabricated on steel hard disk drive suspensions also show excellent results. The sensor not only has a better signal-to-noise ratio but also detects more vibration information than the combination of two laser-Doppler-vibrometer measurements in different directions.

Development of a large‐current high‐precision pulse power supply

AbstractJAEA and KEK are jointly constructing a high‐intensity proton accelerator project J‐PARC. Its main accelerator is a 3‐GeV synchrotron. Its injection bump magnets, especially horizontal paint bump magnets, are excited by large pulse currents. Their rated currents are over 10 kA and pulse widths are about 1 ms. Tracking errors are required to be less than 1%. Multiple connected two‐quadrant IGBT choppers are adopted for their power supplies. Their output currents are controlled by feedback control with minor loop voltage control (m‐AVR). When output current of a chopper intermits at small current, its output voltage rises and current control becomes difficult. In this paper, response of m‐AVR and output voltage characteristics at current intermittent region are studied and an improved control scheme is proposed. The performance is confirmed by a test. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 62– 72, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20783

The mechanical stress resistance capability of stress buffer structures in analog devices

In this research, we showed that the different stress buffer configurations in the analog device will change the magnitude of the mechanical stress effect on the device surface, which will cause the variation in the output voltage characteristic of the device as well. And, the experimental results reveal that the different stress buffer configurations provide the difference of the mechanical stress resistance capability on the LDO (Low Drop Out) analog device. The stress buffer structure can reduce the stress effect to the LDO analog device effectively, i.e., the variation of the output voltage character of the LDO analog device will be larger if there is no stress buffer structure on the LDO analog device. Our results could be a reference for the design of an analog device and its packaging to improve the performance of the analog device.

Output Voltage Characteristics of Eddy Current Displacement Sensor for Various Heat Treatments of Measuring Objects

The output voltage of an eddy current displacement sensor (EC displacement sensor) depends on the heat treatment of the measuring object. The EC displacement sensor must detect a displacement of several tens of μm to allow the examination of the change in output voltage due to the heat treatment of the measuring object. Thus, we measure the relative permeability and resistivity of four objects made of chromium molybdenum steel that have undergone different heat treatments (initial condition (INT), salt quenching (SAQ), annealing (ANL), and vacuum furnace cooling (VFC)). In addition, we examine the relationship between the heat treatment of the measuring objects and the output voltage characteristics of the sensor at a displacement between the measuring object and the sensor of 1 mm. The result shows that the relative permeability of measuring object varies between 35 and 80, and resistivity varies between 0.18 μΩm and 0.35 μΩm due to different heat treatment conditions. The sensitivities of the sensor after SAQ and VFC treatments of the measuring object are 82.0 V/m and 73.0 V/m, respectively; thus, the difference is -11%.

1325 金属コア圧電ファイバ/アルミニウム複合材料の出力電圧特性(J14-5 知的材料・構造システム(5) 圧電素子とその応用,ジョイントセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

This paper describes the output voltage characteristics of the metal core piezoelectric ceramic fiber/aluminum composite. In this study, the thin patch type device developed by Interphase Forming/Bonding Method in the previous study was evaluated by the oscillation test. As the result, the output voltage from the device was proportional to its strain, independent of its strain rate and changed with its strain direction. In addition, it was also cleared that the phase difference between the output voltage and the displacement of the oscillation plate was changed at a certain strain direction by the difference between the longitudinal piezoelectric constant and the transverse one.

1.2[kW]급 연료전지용 전력변환장치의 개발

연료전지 발전시스템에서는 DC-DC승압용 컨버터와 DC-AC 인버터가 필요하다. 그러므로 본 논문에서는 연료전지의 전압을 380[VOC]로 승압하기 위한 절연형 DC-DC 컨버터와 단상 220[VAC]로 변환하기 위한 LC필터를 가진 PWM 인버터로 구성된 전력변환장치를 제안하였다. 특히 제안한 연료전지 시스템용 고효율 DC-DC 컨버터는 위상천이 PWM 제어법을 이용하여 부분 공진에 의한 ZVS를 실현하였으며, 일정 스위칭 주파수화 및 스위치의 스위칭 손실, 피크 전압과 전류를 저감시켰다. 그리고, 정류회로에 2개의 인덕터를 첨가하여 리플성분이 저감된 직류전압과 전류를 부하측에 안정하게 공급할 수 있었다. 또한, 넓은 출력 전압 조정에도 효율을 92[%]정도 얻을 수 있다. 이상과 같이 결과는 시뮬레이션과 실험을 통하여 그 타당성을 확인하였다.

브이용 전력시스템 설계 및 분석

본 논문은 브이용 PV 시스템 성능과 최대전력점추적기의 알고리즘에 대하여 기술하고자 한다 현재 운영되고 있는 브이는 대부분 태양광을 활용한 독립형 전력 시스템을 이용하고 있다. 이러한 태양광 전력 시스템은 직류 출력 특성을 가지고 있으며 직류 버스와 연결된다. 태양광 전지판의 I-V 출력 특성은 일사량, 전지판의 온도에 따라 변화하며 태양광 전지 마다 그 특성이 각기 다르게 나타나기 때문에 태양광 전지는 최대전력추적방식의 알고리즘에 의해 운영되어야 한다. 이에 본 논문은 태양광 전지의 특성, 최대전력추적방식, 태양광 전지판의 최적경사각을 논의하고자 한다. This paper presents the performance of PV(Photovoltaic) system, the design of MPPT(Maximum Power Point Tracker). Output of PV power system is DC, and PV power system is linked to the DC bus. The current(I)-voltage(V) output characteristic of PV cells changes with solar irradiance and cell temperature as parameters. As various PV modules respond differently to each of the parameters cited above. Maximum output of PV modules am be achieved by MPPT(Maximum Power Point Tracker) algorithm This paper includes a discussion on the performance of PV module, MPPT algorithm and the influence of PV module angle.

Fabrication and characterization of a GaAs-based three-terminal nanowire junction device controlled by double Schottky wrap gates

A three-terminal nanowire junction device controlled by double nanometer-sized Schottky wrap gates (WPGs), which control left and right branches independently, are fabricated utilizing AlGaAs∕GaAs etched nanowires and characterized experimentally. Fabricated device exhibits clear nonlinear characteristics of output voltage at the center terminal by applying voltages to left and right terminals in push-pull fashion. Applying asymmetric gate voltages to left and right WPGs provides clear asymmetry in the output voltage. The nonlinearity in the low voltage regions is greatly enhanced by squeezing both left and right branches using WPGs.

3[kW]급 연료전지용 전력변환장치의 개발

최근 저전압ㆍ대전류 출력 특성을 갖는 연료전지를 위한 새로운 발전시스템으로 주목받고 있다. 연료전지 발전시스템에서는 DC-DC 승압용 컨버터와 DC-AC 인버터가 필요하다. 그러므로 본 논문에서는 연료전지의 전압을 380[V<SUB>DC</SUB>]로 승압하기 위한 절연형 DC-DC 컨버터와 단상 220[V<SUB>AC</SUB>]로 변환하기 위한 LC필터를 가진 PWM 인버터로 구성된 전력변환장치를 제안하였다. 특히 제안한 고주파 절연형 ZVZCS PWM DC-DC 컨버터는 환류 다이오드를 포함한 탭부 인덕터 필터를 이용하여 순환 전류를 저감시켰으며, 스위치 및 변압기의 턴-온, 턴-오프시에 오버슈트 전압이나 과도현상이 발생하지 않는다. 그리고 넓은 출력 전압 조정에도 효율을 93~97[%]정도 얻을 수 있으며, 출력 부하전류의 변화에 대해 거의 일정한 출력 전압 특성을 가졌다.

Development of Large Current High Precision Pulse Power Supply

JAEA and KEK are jointly constructing a high intensity proton accelerator project J-PARC. Its main accelerator is 3GeV synchrotron. Its injection bump magnets, especially horizontal paint bump magnets, are excited by large pulse currents. Their rated currents are over 10kA and pulse widths are about 1ms. Tracking errors are required to be less than 1%. Multiple connected two-quadrant IGBT choppers are adopted for their power supplies. Their output currents are controlled by feedback control with minor loop voltage control (m-AVR). When output current of a chopper intermits at small current, its output voltage rises up and current control becomes difficult. In this paper response of m-AVR and output voltage characteristics at current intermittent region are studied and an improved control scheme is proposed. The performance is confirmed by a test.

磁性めっき線のＦｅ薄膜の厚さに依存する渦電流形変位センサの直線範囲

A magnetoplated wire (MPW) is a copper wire whose circumference is plated with a magnetic thin film. The effects of using an MPW are a decrease in the proximity effect, an increase in inductance, and generation of more flux than when copper wire is used. The ratio of the linearity range Lo to the outer coil diameter D of the eddy current displacement sensor is extended by using MPW for the coil. However, the relationship between the Fe film thickness of MPWs and the linearity range characteristic has not been clarified. We measured the output voltage characteristics of MPW coils with Fe film thicknesses of 0.7 μm, 1 μm, and 1.1 μm, and calculated Lo/D ratios. As a result, we found that the Lo/D ratio of an MPW coil with a 1-μm-thick Fe film had a maximum value of 0.66.

Discrete‐time model following control of inverter with rectifier load

AbstractElectronic apparatus, such as a computer, are a capacitor input type rectifier load for the power supply. The rectifier load causes distortions of the power source voltage waveform. Copyright © 2004 Wiley Periodicals, Inc.This paper describes the output voltage characteristic of the single phase PWM inverter controlled by a discrete‐time model following method and connected to a rectifier load. First, the rectifier load model of a discrete‐time system is considered. Next, the discrete‐time model following control system used for this load is described. Then, simulation and experimental results are examined. The simulation results show that this method has robustness to the load change. The experimental system consists of an inverter controlled by a digital signal processor (DSP) and a rectifier load. Experimental results confirmed the validity of the simulation result. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 72–81, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20375

On the use of Feedback Systems to Dynamically Control the Supply Voltage of Low-Power Circuits

In this paper a complete environment to design, model and simulate DVS based processor system is proposed. It is based on the use of a co-processor which continuously computes the real average speed of the microprocessor. The whole system is modeled as a feedback system and simulated using a mixed signal simulation environment. It is shown how energy saving can be achieved using software and hardware dynamic voltage regulation. Key parameters, such as the set point management, the application computational load profile and the DC/DC output voltage characteristics are considered and their influence on the energy reduction studied. Therefore the proposed architecture and validation environment enable the designer to optimize the overall energy consumption of the system by making relevant trade-offs between software and hardware energy reduction techniques and the overheads brought by the implementation.

Blue-yellow ZnO homostructural light-emitting diode realized by metalorganic chemical vapor deposition technique

We report on the realization of ZnO homojunction light-emitting diodes (LEDs) fabricated by metalorganic chemical vapor deposition on (0001) ZnO bulk substrate. The p-type ZnO epilayer was formed by nitrogen incorporation using N2O gas as oxidizing and doping sources. Distinct electroluminescence (EL) emissions in the blue and yellow regions were observed at room temperature by the naked eye under forward bias. The EL peak energy coincided with the photoluminescence peak energy of the ZnO epilayer, suggesting that the EL emissions emerge from the ZnO epilayer. In addition, the current-voltage and light output-voltage characteristics of ZnO homojunction LEDs have also been studied.

Modeling of giant magnetoresistance isolator for high speed digital data transmission utilizing spin valves

Giant magnetoresistance isolator was modeled for effective transmission of high speed digital data, and the output voltage characteristics depending on pulse width of input signal, inductor coil turn, and existence of external circuit of the planar inductor were investigated in time domain. The planar coil was modeled as a lumped element R,L,C circuit and the coil current was calculated using SPICE. The corresponding magnetic field was substituted to the measured magnetoresistance-H curve to obtain the resistance values of the spin valves, which were used to obtain the output voltage wave form of the isolator. Effective maximum transmission speed of 250Mbit∕s was estimated. Even though the coil current wave form was much deformed with damping, the transmitted output voltage wave form was very close to the rectangular wave form of the input signal due to hysteretic characteristics of the spin valves.

Chemical and pH sensors based on the swelling behavior of hydrogels

Hydrogels show a strong swelling ability in dependence on pH value or solvent concentration in aqueous solutions. This behavior can be used for appropriate sensors if a suitable transducer transforms the volume change into an electrical output signal. In this work, piezoresistive sensors were used where the hydrogel led to a deflection of the silicon membrane within the sensor chip. This principle allows for a strict separation of the fluid from piezoresistors as well as from other electronic components at the sensor chip front side. Poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) blend as well as poly( N-isopropylacrylamide) (PNIPAAm) have been applied and investigated for pH sensors and organic solvent concentration sensors, respectively. The output voltage versus pH value characteristics and the long-term signal stability of hydrogel-based sensors were investigated and the measurement conditions necessary for high signal reproducibility were determined. The influence of the preparation conditions of the hydrogel films on the sensitivity and response time of the chemical and pH sensors is discussed.

整流器負荷を有するインバータの離散時間モデル追従制御

Electronic apparatus, such as a computer, are a capacitor input type rectifier load for the power supply. The rectifier load causes distortions of the power source voltage waveform. Copyright © 2004 Wiley Periodicals, Inc. This paper describes the output voltage characteristic of the single phase PWM inverter controlled by a discrete-time model following method and connected to a rectifier load. First, the rectifier load model of a discrete-time system is considered. Next, the discrete-time model following control system used for this load is described. Then, simulation and experimental results are examined. The simulation results show that this method has robustness to the load change. The experimental system consists of an inverter controlled by a digital signal processor (DSP) and a rectifier load. Experimental results confirmed the validity of the simulation result. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 72–81, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20375

스핀밸브를 이용한 데이터 전송용 GMR 아이솔레이터의 모델링

GMR isolator was modeled using a Wheatstone bridge which is profitable for transmitting rectangular wave digital data, and the output voltage characteristics in relation to the input current were investigated in time domain. GMR isolator modeling was divided into two parts, namely magnetic and electric parts. The flow chart of the modeling was drawn in which measured MR curve of the spin valves were incorporated to obtain the electrical voltage output. For magnetic modeling, 3-dimensional model of planar coil was analyzed by FEM method to obtain the magnetic field strength corresponding to the input current. For electric modeling, resistance, inductance and capacitance of the planar coil were calculated and magnetic field waveform was obtained corresponding to the coil current waveform in time domain. Finally, MR-H curves of spin valves and the magnetic field waveform at the spin valves were composited to obtain the output voltage waveform of the isolator. Even though the amplitude of the coil current waveform was increased by 100％, decreased by 90％, or delayed by 10％ of the period compared with the input current, similar transmitted output voltage waveform to the input current waveform was obtained due to hysteretic characteristics of the spin valves at the transmission speed of over 400 Mbit/s.

Novel Vector Control System Using Deadbeat-Controlled PWM Inverter With Output LC Filter

This paper proposes a novel high-performance vector control system of an ac motor using a low-switching-frequency (2 kHz) pulsewidth-modulation voltage-source inverter with an output LC filter. Excellent high-speed response characteristics of the LC filter output voltage have been realized using a novel deadbeat control algorithm. As for the experimental results, the torque current response that is similar to the response of the conventional system without an LC filter has been obtained. In addition, it has been confirmed by simulation that errors of the LC filter constants within /spl plusmn/10% can be permitted.

Development of a Composite Rectifier Circuit for a Partially Smoothing Circuit and a Voltage Doubler Rectifier Circuit

A composite rectifier circuit for a partially smoothing circuit and a voltage doubler rectifier circuit is proposed. The proposed rectifier circuit has the same smoothing output voltage characteristics as the partially smoothing circuit, but its input characteristics are greatly improved: The total capacity of the three capacitors in the composite circuit is reduced by 37%, even though one more dc-capacitor is needed. The crest factor of the input current is reduced from 2.25 to 1.36. The input power factor is increased from 0.948 to 0.969. The relative harmonics content rate is reduced from 32.2% to 12.7%. The rush current produced at power switch ON is effectively suppressed since the small capacitance is available to the input capacitor.