Practical methods of device and circuit modelling

Magnitude-phase equivalent circuit and steady-state power-angle characteristic analysis of DFIG

Equivalent circuit modeling of power equipment is a crucial foundation for power system analysis, fault diagnosis, and monitoring equipment health. Traditional circuit modeling methods rely on manual identification and calculations. These approaches are inefficient and prone to errors when handling complex circuits. This paper proposes an automatic modeling and simulation system for equivalent circuits of power equipment based on intelligent image recognition. The system uses deep learning technology for automatic component recognition in circuit diagrams and applies image processing algorithms to detect node connection relationships. It automatically establishes Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL) equation systems—standard electrical circuit principles to describe current and voltage flows—and then solves circuit frequency-domain characteristics using state-space equations. The system features a triple verification framework. It cross-validates the results from intelligent recognition and automatic calculations with simulation results from manually constructed Multisim models and automatically generated Simulink simulation models via a JSON (JavaScript Object Notation) interface. Using the equivalent circuit of a transformer winding as an example, experimental results show that the system can accurately identify repetitive unit structures, extract circuit features, and establish mathematical models. The high-frequency impedance spectra calculated by the intelligent method agree with results from manual simulation in Multisim and automatic modeling in Simulink. This validates the intelligent modeling method's effectiveness and accuracy. The system automates circuit modeling, providing an efficient and intelligent solution for a wide range of power equipment.

An improved nonlinear modeling technique for high electron mobility transistors (HEMT) based on the combination of the conventional equivalent circuit and artificial neural network (ANN) modeling techniques is presented. Effective initial values of the artificial neural network for each nonlinear element in HEMT model are evaluated from a semi-analytical parameter extraction technique. A multi-goal DC, S-parameter, and harmonic (DC/S/HB) training process has been formulated. Good agreement is obtained between the model and data of the DC, S parameter, and harmonic performance for a 200um gate width 0.25μm PHEMT (FHX04LG) over a wide range of bias points.

The dipole antennas are widely used for RF communication applications and usually provide a potential front-door path of coupling electromagnetic pulse (EMP). In this paper, the transient current response of dipoles exposed to EMP is calculated with an equivalent circuit based model, which consists of an equivalent pulse voltage source and an antenna equivalent circuit. A center-driven wire dipole and a normal mode helical antenna are utilized for validate the circuit models. The results from the circuit based models agree well with data obtained from full numerical solution of the actual antennas. They takes only a few seconds to calculate the transient response with circuit models, which could also be directly connected to RF front-end circuits of communication system for electromagnetic susceptibility assessment.

As power electronic engineers increase the switching speed of voltage source converters for the purpose of higher power density, the dI/dt and dV/dt across the power semiconductors increases as well. A well-known adverse consequence of high dV/dt is parasitic turn-on of the power device in the same phase leg as the device being triggered. This causes a short circuit with high shoot-through current, high instantaneous power dissipation and possibly device degradation and destruction. It is critical for converter designers to be able to accurately predict this phenomenon through diagnostic and predictive modelling. In this paper, a physics-based device and circuit model is presented together with experimental results on parasitic turn-on of IGBTs in voltage source converters. Because the model is physics based, it produces more accurate results compared with compact circuit models like SPICE and other circuit models that use lumped parameters. The discharge of the Miller capacitance is simulated as a voltage dependent depletion capacitance and an oxide capacitance as opposed to a lumped capacitor. The model presented accurately simulates IGBT tail currents, PiN diode reverse recovery and the non-linear miller capacitance all of which cannot be solved by lumped parameter compact models. This is due to the fact that the IGBT current in the model is calculated using the Fourier series based re-construction of the ambipolar diffusion equation and the miller capacitances are calculated using fundamental device physics equations. This paper presents a physics-based device and circuit model for parasitic turn-on in silicon IGBTs by numerically modelling the minority carrier distribution profile in the drift region. The model is able to accurately replicate the transient waveforms by avoiding the use of lumped parameters normally used in compact models.

Over the years, there has been tremendous progress in developing new methods for modeling and diagnosing reliability at the level of individual transistors and interconnects. The thrust to propagate these models to higher levels of abstraction to predict the reliability of larger circuits is much more recent. This paper addresses the intersection of physics, circuits, and architecture for reliability modeling and optimization that must come together for cross-layer optimization. For various device reliability phenomena, this paper shows how physical models can be leveraged at the circuit level, or circuit models at the architecture level, to deliver composite solutions that comprehend chip-level design goals.

A new equivalent circuit for the insulated-gate field-effect transistor (IGFET) is described. This device model is particularly useful for computer-aided analysis of monolithic integrated IGFET switching circuits. The results of computer simulations using the new equivalent circuit are in close agreement with experimental observations. As an example of a practical application, simulation results are shown for an integrated circuit IGFET memory cell.

Extensive work has been done in the last three decades on modelling classical semiconductor devices through physical device models. The majority of these models is based on the simultaneous solution of Poisson's equation, current and continuity equations for electrons and holes using iterative techniques. The vast work done on classical semiconductor devices has been extended to include the study of the motion of charged species upon the application of external fields in insulators, ionic materials, mixed conductors or proton conductors. In this paper the methods used are discussed together with their potential in leading to an understanding of the mechanisms governing charge transport in materials exhibiting more complex conductivity than classical semiconductors.

The small-signal rate equations for a semiconductor laser can be represented as a network of electrical components, as shown by Tucker and Kaminow [R. S. Tucker and I. P. Kaminow, J. Lightwave Technol. LT-2, 385 (1984)] for the case of finite gain compression ε>0. However, a calculation of small-signal response curves δS/δI vs I derived from this equivalent circuit exhibit a linear decrease (“droop”) above threshold that is inconsistent with the dc solutions of the original rate equations. This problem flags a subtle flaw in the formulation of the circuit model. We observe, moreover, that the expression for the resonance damping parameter used throughout the laser literature follows exactly from this same RLC circuit model. The derivation of the circuit model from the rate equations is revisited. Consistency between the dc and ac solutions is achieved when the differential of the net gain δ{G/(1+εS)} is appropriately represented as a shunt element with zero admittance. The corrected circuit model resolves the “droop” problem in the small-signal δS/δI vs I relation. As expected, the new circuit model leads to a modified expression for the damping parameter.

The growing use of electric vehicles has led to an ever-increasing demand for efficient and reliable management systems to control the behavior of lithium-ion batteries, especially with respect to heat generation and state-of-charge. Understanding these patterns constitutes a major new challenge for these batteries, as remaining ignorant of their behavior can result in decreased performance, shorter service life and even safety dangers. This review provides an overview of the different modeling techniques applied to simulate battery behavior. Different methods using equivalent electrical circuit models are discussed, covering both simple battery models and more complex equivalent electrical circuit models, with a focus on the 2RC-Thévenin circuit model. In this context, parameter approach methods for these systems are reviewed. In addition, laboratory tests are run to identify the various model parameters for a lithium-ion battery. This comprehensive study is designed to guide scientists and engineers in the selection and use of suitable tools for state-of-charge and battery health studies.

On the nanoscale, equivalent circuit models are not scale invariant. An ideal equivalent circuit can be a valid model of a device at the macro or even micro-scale, but it might not reveal even the qualitative properties of the same device during downscaling. We illustrate the consequences of downscaling to the nanoscale with an example, the nanoscale capacitor. The circuit models combine four groups of state variables: (1) classical mechanical, (2) classical electromagnetic, (3) quantum mechanical, and (4) quantum electromagnetic. In general, a quantum-classical equivalent circuit is combined from four coupled “subcircuits,” representing the classical mechanical dynamics of the nuclei, the classical dynamics of the electromagnetic field, the quantum wave-dynamics of the electrons, and the QFT dynamics of photons. The modeling procedure should determine the state-variables of the four subcircuits and their couplings.

Presently, there are mainly two problems that prevent Electric Vehicles (EVs) from becoming popular against the Internal Combustion Engine Vehicles (ICEVs), namely: short range and too long to recharge the battery pack of the EV. Due to this, battery development is a crucial aspect to improve the performance of EVs. This progress requires dependable computer aided designs to model the characteristics of a battery accurately and reliably. This paper uses Power Systems Computer Aided Design (PSCAD) to create an equivalent runtime circuit model to observe the qualities of the Lithium Iron Phosphate battery cell under discharge at different temperatures. The model is a 3-R-C branch runtime equivalent circuit model. In order to find the fixed parameters of the circuit, MATLAB was used to implement basic current voltage characteristics. 3-D tables have been used in PSCAD to implement the State of Charge (SOC) and temperature dependent circuit parameters of the model. Once the simulations for all temperatures were completed, the average marginal error between measured and simulated terminal voltage came to be 2.1%, therefore making PSCAD an accurate simulation tool for modeling equivalent circuits of different batteries.

As the operating frequency of integrated circuit (IC) is rapidly increased, the importance of electromagnetic compatibility (EMC) performance test in the design stage of IC development process is becoming more significant. The new EMC test method, IC-Stripline enables fast and accurate EMC test with smaller form factor and lower cost compared with transverse electromagnetic (TEM) cell which is the most widely used for radiated electromagnetic interference test at the moment. This paper presents the equivalent lumped-element circuit model to capture capacitive and inductive coupling between open version of IC-Stripline and an IC package. Also, the equations to calculate the circuit components with geometrical structure of IC-Stripline are proposed. The S-parameter results from presented circuit models are compared against those obtained by 3D EM solver. The presented models are very accurate up to 3 GHz which is the upper limit of effective frequency range of IC-Stripline described in IEC standards [1], [2]. Therefore, the proposed IC-Stripline models can be effectively used to predict radiated emission and immunity of ICs using circuit level simulation tools.

Some recent modeling results of Chalmers manufactured InP HEMT devices are presented in this paper. Device models and measurements as well as comparison to simulation programs are studied. The equivalent circuit and large signal model are verified by comparing measurements and computer simulations for DC characteristics, S-parameters and power spectrum.

Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.