The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Qing-an Huang - One of the best experts on this subject based on the ideXlab platform.
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A Nodal Analysis model for the out-of-plane beamshape electrothermal microactuator
Microsystem Technologies, 2008Co-Authors: Qing-an HuangAbstract:This paper introduces a Nodal Analysis model for the out-of-plane beamshaped electrothermal microactuators. The electrothermal microactuator is traditionally simulated with finite element method (FEM) due to the complex coupling of the electrical, thermal and mechanical problem. This complex problem is classified into two parts in this paper: the coupling electrothermal problem and the coupling thermomechanical problem. By utilizing the characteristic of the temperature distribution, the Nodal Analysis model for the coupling electrothermal behavior of the electrothermal microactuator is built. The model scale is much smaller than the finite element model, which results in less computational consumption. Then the coupling thermomechanical behavior, such as the shift of the heat flow from the bottom of each part of the actuator to the substrate due to its out-of-plane movement, is modeled to make the model more reasonable. Many other effects which remarkably influence the behavior of the actuator are also taken into account. This model is verified by available experimental results, and achieves an agreement.
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A Nodal Analysis method for simulating the behavior of electrothermal microactuators
Microsystem Technologies, 2007Co-Authors: Qing-an HuangAbstract:This paper presents a novel approach to verify and optimize surface micromachined electrothermal microactuators by using a Nodal Analysis method. The Nodal Analysis method for the mechanical and electrostatic devices is a schematic-based method which simplifies the design of MEMS devices significantly. A variety of the surface micromachined electrothermal microactuators have been widely applied in various areas due to the high force provided at a relatively low input voltage. These electrothermal microactuators can also be decomposed into essential elements of beams and anchors. This paper presents the Nodal Analysis method for the electrothermal microactuators. The temperature dependent properties for the thermal conductivity, electrical resistivity and thermal expansion coefficient of polysilicon beams are included. The effect of the effective axial length for the beams due to lateral deflection and large axial stress is also taken into account. This approach is verified by ANSYS and the simulation data agrees well with each other. It extends the general Nodal analyses method to simulate the electrothermal microactuators.
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A Nodal Analysis Method for Laterally-Driven Electrothermal Microacutators
Journal of Physics: Conference Series, 2006Co-Authors: Qing-an HuangAbstract:This paper introduces a novel method for the simulation and verification of the laterally-driven electrothermal microactuator. A Nodal Analysis model of the electrothermal microactuator was built without meshing. This model may simulate the static and dynamic behaviour of the electrothermal microactuators with variational thermal conductivity, electrical resistivity and thermal expansion coefficient. There are only three stages of ODEs in the model, but its static relative error is below 5% in comparison with the results of the nonlinear model of ANSYS with the nonlinear geometrical options turned on. The equivalent circuit was then built to present the capability of co-simulating with the control and feedback circuits.
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A Nodal Analysis model for out-of-plane beamshaped electrothermal microactuators
2006 8th International Conference on Solid-State and Integrated Circuit Technology Proceedings, 2006Co-Authors: Qing-an HuangAbstract:This paper originally introduces a Nodal Analysis model for the out-of-plane beam-shaped electrothermal microactuator, which could simulate the temperature distribution along the actuator and the Nodal displacement of the actuator. The beam is extracted as the essential element from this kind of actuators. With the temperature correlation along the beam taken into account, the computational complexity is significantly reduced to build the coupled electrothermal model of the beam. The Nodal model of the beam with 12 degrees of freedom is utilized to represent the out-of-plane electrothermal microactuator which takes the effect of the change of axial length and large axial stress into account. The temperature dependent thermal conductivity of the beam and the air, heat convection coefficient of the beam surface, and the electrical resistivity are also calculated in the model of the beam. Simultaneously, the change of the gap between the beam and the substrate while actuating which is related closely to the heat transfered from the beam to the substrate, is included in the model. This Nodal Analysis model of the beam is verified by the published experiment results of the out-of-plane electrothermal microactuator fabricated at MUMPs
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Nodal Analysis of the in-plane thermal microactuator
Proceedings. 7th International Conference on Solid-State and Integrated Circuits Technology 2004., 1Co-Authors: Qing-an HuangAbstract:The behavior of a thermal microactuator was conventionally simulated by FE or FD method in the past. A novel approach is proposed to simulate the behavior of the thermal microactuator with the Nodal Analysis method in this paper. The approach can build the macromodel of the thermal microactuator by odd continuation and Fourier transform based on the traditional Nodal Analysis method. Unlike the model order reduction method, this approach has apparent physical meaning which leads to a good understandability. This approach is then verified by the FE method and the results agree well with each other.
Phillip E. Moseley - One of the best experts on this subject based on the ideXlab platform.
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Nodal Analysis for SAGD Production Wells with Gas Lift
All Days, 2015Co-Authors: Grant J. Duncan, Scott A. Young, Phillip E. MoseleyAbstract:Abstract Steam Assisted Gravity Drainage (SAGD) is an enhanced oil recovery process wherein a long horizontal steam injection well is located above a long horizontal production well. Injected steam forms a steam chamber above the SAGD well pair, heating the reservoir rock and reservoir fluids. Heated oil (or bitumen) plus condensed steam flow down the sides of the steam chamber towards the production well. The condensed steam and bitumen are then lifted to surface with a downhole pump or by gas lift. Due to a rapidly increasing number of SAGD well pairs, Suncor required a tool that could accurately model these challenging thermal production wells. Nodal Analysis for well performance is based on the principle that reservoir inflow and wellbore outflow can be independently characterized as functions of flow rate and pressure. Nodal Analysis is used to design new wells and optimize production or injection on existing wells. Wellbore simulations are cheaper than instrumentation, meters or single well tests. Well evaluation software is the most popular engineering package in Suncor's production engineering toolkit because it is very accurate and easy to use. Over the past few years Suncor worked with their software provider to develop Nodal Analysis for SAGD production wells. Suncor can now model SAGD producers with electric submersible pumps (ESPs) and gas lift with a high degree of confidence. The new SAGD Nodal models quite closely match production rates, plus surface and downhole pressure and temperature data. Reliable and rigorous SAGD Nodal models enable improved decisions with respect to SAGD field development and production optimization. Nodal Analysis can be used as a predictive tool for production optimization, or for a better understanding of what is happening downhole with respect to temperature, pressure, and flow distribution within the wellbore. This paper is a logical continuation of SPE 170054, Nodal Analysis for SAGD Production Wells with ESPs (ref 1). The main difference between modeling wells with gas lift rather than mechanical lift is that the gas lift models also account for steam lift. Steam lift occurs when some of the produced water (PW) in the emulsion flashes to steam as pressure is reduced. The resulting vapour significantly augments gas lift and reduces lift gas requirements.
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Nodal Analysis for SAGD Production Wells with ESPs
Day 2 Wed June 11 2014, 2014Co-Authors: Grant J. Duncan, Richard Michael Stahl, Phillip E. MoseleyAbstract:Abstract Steam Assisted Gravity Drainage (SAGD) is an enhanced oil recovery process whereby a long horizontal steam injection well is located above a long horizontal production well. Injected steam forms a steam chamber above the SAGD well pair, heating the reservoir rock and reservoir fluids. Heated oil (or bitumen) plus condensed steam flows down the sides of the steam chamber towards the production well. The condensed steam and bitumen are then lifted to surface with a downhole pump or by gas lift. Over the past decade, SAGD has become an increasingly popular method for extracting bitumen from Canadian oilsand leases that are too deep for surface mining, largely due to the high recovery factor from SAGD. Nodal Analysis for oil and gas wells enables the user to model well production or injection performance from the producing reservoir to the surface gathering system. Nodal Analysis for well performance is based on the principle that reservoir inflow and wellbore outflow can be independently characterized as functions of flow rate. The single rate that balances the pressure losses in the inflow-outflow components with the pressure drop across the total system defines well flow. Nodal Analysis is used to design new wells and optimize production or injection on existing wells. In addition, wellbore simulations are cheaper than instrumentation, meters or single well tests. Well evaluation software is the most popular package in Suncor's conventional production engineering toolkit because it is very accurate and easy to use. Due to a rapidly increasing number of SAGD well pairs, Suncor required a tool that could accurately model these thermal wells. Over the past few years we worked with our software provider to develop Nodal Analysis for SAGD production wells, and we can now model SAGD producers with electric submersible pumps (ESP) with a high degree of confidence. The new SAGD Nodal models quite closely match production rates, plus surface and downhole pressure and temperature data. Reliable and rigorous SAGD Nodal models will enable improved decisions with respect to SAGD field development and production optimization.
Carlos Sánchez-lópez - One of the best experts on this subject based on the ideXlab platform.
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Symbolic Nodal Analysis of Analog Circuits with Modern Multiport Functional Blocks
2013Co-Authors: Carlos Sánchez-lópez, A. Ruiz-pastor, R. Ochoa-montiel, M. A. Carrasco-aguilarAbstract:Abstract. This paper proposes admittance matrix models to approach the behavior of six modern multiport functional blocks called: differential difference amplifier, differential difference operational floating amplifier, differential difference operational mirror amplifier, differential difference current conveyor, current backward transconductance amplifier and current differencing transconductance amplifier. The novelty is that the behavior of any active device mentioned above can immediately be introduced in the Nodal admittance matrix by using the proposed admittance matrix models and without requiring the use of extra variables. Therefore, a standard Nodal Analysis is applied to compute fully-symbolic small-signal performance parameters of analog circuits containing any active devices mentioned above. This means that not only the size of the admittance matrix is smaller than those generated by applying modified Nodal Analysis method, for instance, but also, the number of nonzero elements and the generations of cancellation-terms are both reduced. An Analysis example for each amplifier is provided in order to show the useful of the proposed stamps.
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Symbolic Nodal Analysis of fully-differential analog circuits
2013 IEEE 4th Latin American Symposium on Circuits and Systems (LASCAS), 2013Co-Authors: Carlos Sánchez-lópez, A. Ruiz-pastor, R. Ochoa-montiel, B. M. Gonzalez-contrerasAbstract:In this paper, a simple element stamp for floating or grounded voltage-controlled voltage sources is proposed. The novelty is that not only the behavior of single-ended, fully-differential and balanced differential operational amplifiers can directly be introduced in the admittance matrix without extra variables, but also the new stamp has few nonzero elements. As a consequence, a reduced and sparse system of equations is built, which means that the computational complexity and memory consumption during the solution of the system of equations by using recursive determinant-expansion techniques are both enhanced. Three Analysis examples are used to show that fully-symbolic transfer functions of single-ended, fully-differential and balanced differential analog circuits can be computed by using standard Nodal Analysis. Furthermore, symbolic expressions for the common-mode rejection ratio of the fully-differential amplifiers are also computed.
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Pathological Equivalents of Fully-Differential Active Devices for Symbolic Nodal Analysis
IEEE Transactions on Circuits and Systems I: Regular Papers, 2013Co-Authors: Carlos Sánchez-lópezAbstract:The use of pathological elements (i.e., nullators, norators, and the voltage mirror-current mirror pair) as universal active elements opens up the possibility to model the behavior of active devices with either differential features or input-output multiples, in order to be used in Analysis tasks of linear(ized) analog circuits. This brief tries on the modeling this class of active devices, which is carried out by considering the impedance characteristics along with the behavior equation of each active device, the kind of signal to be processed and by applying the pathological element properties. In order to obtain a more realistic model, not only parasitic elements associated to the input-output terminals of each active device are considered, but the tracking errors of voltage and current differential followers modeled with grounded pathological elements and admittances are also included. Due to that the gain and tracking errors are finites and of limited bandwidth, a two-pole model is used for each of them in order to include their contributions on the symbolic expressions computed. Because the behavior of fully-differential amplifiers is modeled with grounded pathological elements, a standard Nodal Analysis can be performed. This imply that not only the size of the admittance matrix is smaller than those generated by applying modified Nodal Analysis (MNA) method, for instance, but also the number of nonzero elements and the generation of cancellation-terms are both reduced. As a result, the computational complexity during the solution of the system of equations is reduced when recursive determinant-expansion techniques are applied. Examples are described and compared with the MNA method, in order to show the usefulness of the proposed models to compute fully-symbolic small-signal characteristics of analog circuits containing fully-differential active devices and/or with input-output multiples.
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NEWCAS - Symbolic Nodal Analysis of analog integrated circuits using pathological elements
10th IEEE International NEWCAS Conference, 2012Co-Authors: Esteban Tlelo-cuautle, Carlos Sánchez-lópez, Sheldon X.-d. TanAbstract:Improvements in analog signal processing applications require the selection of adequate active devices. However, each kind of active device offers different port-characteristics. For instance, the parasitic elements play an important role in selecting the best one for a given application. Symbolic Nodal Analysis is a useful tool to derive electrical characteristics of analog circuits, but compact models for the active devices are required to generate small matrices and analytical expressions. That way, this paper shows the usefulness of using pathological elements to generate behavioral models including dominant parasitic elements. The proposed approach is useful for the selection of active devices in analog design and synthesis procedures.
Denis Hau Aik Lee - One of the best experts on this subject based on the ideXlab platform.
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Voltage Stability Assessment Using Equivalent Nodal Analysis
IEEE Transactions on Power Systems, 2016Co-Authors: Denis Hau Aik LeeAbstract:This paper presents a simple method for voltage stability assessment by reducing the bus impedance matrix of a network into its two-bus equivalent model at a referred bus. Closed-form equations of the equivalent model could then be derived to facilitate an equivalent Nodal Analysis at the referred bus to determine its voltage stability limit. The method was also shown to have parallels with the well-accepted modal Analysis of the Jacobian matrix. These include defining geometric indices to identify critical buses and participation factors to quantify contribution of network elements to their criticality. The method however does not require post power flow solution processing of the Jacobian matrix; such computational advantage may make it suitable for online applications. The IEEE 300-bus system was tested with the method which was shown to be valid and computationally robust and efficient.
Grant J. Duncan - One of the best experts on this subject based on the ideXlab platform.
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Nodal Analysis for SAGD Production Wells with Gas Lift
All Days, 2015Co-Authors: Grant J. Duncan, Scott A. Young, Phillip E. MoseleyAbstract:Abstract Steam Assisted Gravity Drainage (SAGD) is an enhanced oil recovery process wherein a long horizontal steam injection well is located above a long horizontal production well. Injected steam forms a steam chamber above the SAGD well pair, heating the reservoir rock and reservoir fluids. Heated oil (or bitumen) plus condensed steam flow down the sides of the steam chamber towards the production well. The condensed steam and bitumen are then lifted to surface with a downhole pump or by gas lift. Due to a rapidly increasing number of SAGD well pairs, Suncor required a tool that could accurately model these challenging thermal production wells. Nodal Analysis for well performance is based on the principle that reservoir inflow and wellbore outflow can be independently characterized as functions of flow rate and pressure. Nodal Analysis is used to design new wells and optimize production or injection on existing wells. Wellbore simulations are cheaper than instrumentation, meters or single well tests. Well evaluation software is the most popular engineering package in Suncor's production engineering toolkit because it is very accurate and easy to use. Over the past few years Suncor worked with their software provider to develop Nodal Analysis for SAGD production wells. Suncor can now model SAGD producers with electric submersible pumps (ESPs) and gas lift with a high degree of confidence. The new SAGD Nodal models quite closely match production rates, plus surface and downhole pressure and temperature data. Reliable and rigorous SAGD Nodal models enable improved decisions with respect to SAGD field development and production optimization. Nodal Analysis can be used as a predictive tool for production optimization, or for a better understanding of what is happening downhole with respect to temperature, pressure, and flow distribution within the wellbore. This paper is a logical continuation of SPE 170054, Nodal Analysis for SAGD Production Wells with ESPs (ref 1). The main difference between modeling wells with gas lift rather than mechanical lift is that the gas lift models also account for steam lift. Steam lift occurs when some of the produced water (PW) in the emulsion flashes to steam as pressure is reduced. The resulting vapour significantly augments gas lift and reduces lift gas requirements.
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Nodal Analysis for SAGD Production Wells with ESPs
Day 2 Wed June 11 2014, 2014Co-Authors: Grant J. Duncan, Richard Michael Stahl, Phillip E. MoseleyAbstract:Abstract Steam Assisted Gravity Drainage (SAGD) is an enhanced oil recovery process whereby a long horizontal steam injection well is located above a long horizontal production well. Injected steam forms a steam chamber above the SAGD well pair, heating the reservoir rock and reservoir fluids. Heated oil (or bitumen) plus condensed steam flows down the sides of the steam chamber towards the production well. The condensed steam and bitumen are then lifted to surface with a downhole pump or by gas lift. Over the past decade, SAGD has become an increasingly popular method for extracting bitumen from Canadian oilsand leases that are too deep for surface mining, largely due to the high recovery factor from SAGD. Nodal Analysis for oil and gas wells enables the user to model well production or injection performance from the producing reservoir to the surface gathering system. Nodal Analysis for well performance is based on the principle that reservoir inflow and wellbore outflow can be independently characterized as functions of flow rate. The single rate that balances the pressure losses in the inflow-outflow components with the pressure drop across the total system defines well flow. Nodal Analysis is used to design new wells and optimize production or injection on existing wells. In addition, wellbore simulations are cheaper than instrumentation, meters or single well tests. Well evaluation software is the most popular package in Suncor's conventional production engineering toolkit because it is very accurate and easy to use. Due to a rapidly increasing number of SAGD well pairs, Suncor required a tool that could accurately model these thermal wells. Over the past few years we worked with our software provider to develop Nodal Analysis for SAGD production wells, and we can now model SAGD producers with electric submersible pumps (ESP) with a high degree of confidence. The new SAGD Nodal models quite closely match production rates, plus surface and downhole pressure and temperature data. Reliable and rigorous SAGD Nodal models will enable improved decisions with respect to SAGD field development and production optimization.