The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Kuo Tsi Chang - One of the best experts on this subject based on the ideXlab platform.
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Effects of a Parallel Resistor on Open-Circuit Transient Response of a Piezoelectric Vibrator
Japanese Journal of Applied Physics, 2003Co-Authors: Kuo Tsi Chang, Minsun OuyangAbstract:In this study we describe how a Parallel Resistor with high resistance significantly reduces the DC response time of the open-circuit transient response, but only slightly affects the steady-state response of an unloaded piezoelectric vibrator of 30 KHz. The transient response strongly depends on the time at which the vibrator is switched off, and the DC response time decreases greatly from 220 ms to 6 ms when a Parallel resistance of 100 KΩ is applied.
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Improving the transient response of a bolt-clamped Langevin transducer using a Parallel Resistor.
Ultrasonics, 2003Co-Authors: Kuo Tsi ChangAbstract:This paper suggests a Parallel Resistor to reduce DC time constant and DC response time of the transient response, induced immediately after an AC voltage connected to a bolt-clamped Langevin transducer (BLT) is switched off. An equivalent circuit is first expressed. Then, an open-circuit transient response at the terminals induced by initial states is derived and measured, and thus parameters for losses of the BLT device are estimated by DC and AC time constants of the transient response. Moreover, a driving and measuring system is designed to determine transient response and steady-state responses of the BLT device, and a Parallel Resistor is connected to the BLT device to reduce the DC time constant. Experimental results indicate that the DC time constant greatly exceeds the AC time constant without the Parallel Resistor, and greatly decreases from 42 to 1 ms by a 100-kΩ Parallel Resistor.
Jeffrey H Lang - One of the best experts on this subject based on the ideXlab platform.
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the control of high speed variable reluctance generators in electric power systems
IEEE Transactions on Industry Applications, 1993Co-Authors: D E Cameron, Jeffrey H LangAbstract:This work studies the control of a direct-current (DC) electric power system that is sourced by a variable-reluctance generator. The power system includes the generator and its switching inverter, a filtering capacitor, a distribution network and an electrical load. The network comprises a series Resistor and inductor, while the load comprises a Parallel Resistor, capacitor and power sink. The voltage at the load is regulated by adjusting the rotor angles at which the inverter switches. Both steady-state and transient performance are considered. Simulations are provided to illustrate performance. >
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the control of high speed variable reluctance generators in electric power systems
Applied Power Electronics Conference, 1992Co-Authors: D E Cameron, Jeffrey H LangAbstract:The control of a direct-current electric power system that is sourced by a variable-reluctance generator (VRG) is studied. The power system includes the generator and its switching inverter, a filtering capacitor, a distribution network, and an electrical load. The network comprises a series Resistor and inductor, while the load comprises a Parallel Resistor, capacitor, and power sink. The voltage at the load is regulated by adjusting the rotor angles at which the inverter switches. A method by which a load-voltage controller can be successfully designed for a power system sourced by a VRG is presented. The method employs averaging, global and local linearization, and model order reduction to facilitate the design. With the help of these techniques, a state full-state feedback controller with integral error action is designed. It appears that the controller works quite well. Transients caused by load changes clear quickly without significant overshoot or undershoot; there is no steady-state voltage regulation error: and the load voltage ripple is quite small. Preliminary experimental evidence confirms these expectations. >
Minfang Peng - One of the best experts on this subject based on the ideXlab platform.
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Modelling, analysis and virtual Parallel Resistor damping control of VSC-based DC grid using master–slave control mode
IET Generation Transmission & Distribution, 2018Co-Authors: Xun Wan, Minfang PengAbstract:This study presents a generic linearised modelling method and a virtual Parallel Resistor damping control for a voltage source converter-based high-voltage direct current (HVDC) system including a direct current (DC) grid. The generic modelling method is composed of DC network's equivalent node-admittance matrix and the Thevenin equivalent matrix of all converters. A simplified two-terminal HVDC system is used to identify the key factors influencing the stability of the DC grid easily. Those key factors are proved by two methods, namely, root locus and participation factors analysis. The parameters of the virtual Parallel Resistor damping control are designed using the simplified HVDC system. The performance of the proposed damping control is studied employing the linearised model of the DC grid. Time simulations such as instability suppressing, power-controlled station N − 1 fault, and DC system faults are carried out to validate the effectiveness of the damping control.
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modelling analysis and virtual Parallel Resistor damping control of vsc based dc grid using master slave control mode
Iet Generation Transmission & Distribution, 2018Co-Authors: Xun Wan, Minfang PengAbstract:This study presents a generic linearised modelling method and a virtual Parallel Resistor damping control for a voltage source converter-based high-voltage direct current (HVDC) system including a direct current (DC) grid. The generic modelling method is composed of DC network's equivalent node-admittance matrix and the Thevenin equivalent matrix of all converters. A simplified two-terminal HVDC system is used to identify the key factors influencing the stability of the DC grid easily. Those key factors are proved by two methods, namely, root locus and participation factors analysis. The parameters of the virtual Parallel Resistor damping control are designed using the simplified HVDC system. The performance of the proposed damping control is studied employing the linearised model of the DC grid. Time simulations such as instability suppressing, power-controlled station N − 1 fault, and DC system faults are carried out to validate the effectiveness of the damping control.
Jenpo Lin - One of the best experts on this subject based on the ideXlab platform.
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the functional sequence of hydrogen in electronic conduction of sol gel derived al doped zno films as determined via impedance spectroscopy
Scripta Materialia, 2009Co-Authors: Jenpo LinAbstract:Sol–gel derived Al-doped ZnO (AZO) films were annealed under various degrees of hydrogen reduction treatments. Three sequential equivalent circuits were obtained by simulating the impedance spectra of the AZO films. By interpreting the equivalent circuit elements, the functional sequence of hydrogen in AZO films was disclosed. Hydrogen destroys the energetic barriers at grain boundaries and releases free electrons, which are shown by the presence of a Parallel Resistor–capacitor circuit, a constant phase element and a short Warburg element in equivalent circuits.
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The functional sequence of hydrogen in electronic conduction of sol–gel derived Al-doped ZnO films as determined via impedance spectroscopy
Scripta Materialia, 2009Co-Authors: Jenpo LinAbstract:Sol–gel derived Al-doped ZnO (AZO) films were annealed under various degrees of hydrogen reduction treatments. Three sequential equivalent circuits were obtained by simulating the impedance spectra of the AZO films. By interpreting the equivalent circuit elements, the functional sequence of hydrogen in AZO films was disclosed. Hydrogen destroys the energetic barriers at grain boundaries and releases free electrons, which are shown by the presence of a Parallel Resistor–capacitor circuit, a constant phase element and a short Warburg element in equivalent circuits.
Minoru Fujii - One of the best experts on this subject based on the ideXlab platform.
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combined analysis of energy band diagram and equivalent circuit on nanocrystal solid
Journal of Applied Physics, 2016Co-Authors: Shinya Kano, Masato Sasaki, Minoru FujiiAbstract:We investigate a combined analysis of an energy band diagram and an equivalent circuit on nanocrystal (NC) solids. We prepared a flat silicon-NC solid in order to carry out the analysis. An energy band diagram of a NC solid is determined from DC transport properties. Current-voltage characteristics, photocurrent measurements, and conductive atomic force microscopy images indicate that a tunneling transport through a NC solid is dominant. Impedance spectroscopy gives an equivalent circuit: a series of Parallel Resistor-capacitors corresponding to NC/metal and NC/NC interfaces. The equivalent circuit also provides an evidence that the NC/NC interface mainly dominates the carrier transport through NC solids. Tunneling barriers inside a NC solid can be taken into account in a combined capacitance. Evaluated circuit parameters coincide with simple geometrical models of capacitances. As a result, impedance spectroscopy is also a useful technique to analyze semiconductor NC solids as well as usual DC transport. ...
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combined analysis of energy band diagram and equivalent circuit on nanocrystal solid
Journal of Applied Physics, 2016Co-Authors: Shinya Kano, Masato Sasaki, Minoru FujiiAbstract:We investigate a combined analysis of an energy band diagram and an equivalent circuit on nanocrystal (NC) solids. We prepared a flat silicon-NC solid in order to carry out the analysis. An energy band diagram of a NC solid is determined from DC transport properties. Current-voltage characteristics, photocurrent measurements, and conductive atomic force microscopy images indicate that a tunneling transport through a NC solid is dominant. Impedance spectroscopy gives an equivalent circuit: a series of Parallel Resistor-capacitors corresponding to NC/metal and NC/NC interfaces. The equivalent circuit also provides an evidence that the NC/NC interface mainly dominates the carrier transport through NC solids. Tunneling barriers inside a NC solid can be taken into account in a combined capacitance. Evaluated circuit parameters coincide with simple geometrical models of capacitances. As a result, impedance spectroscopy is also a useful technique to analyze semiconductor NC solids as well as usual DC transport. ...
