# Designing & Modeling Electrical Systems and Devices

## What is the simulation of Electrical Systems?

The use of simulation to design electrical systems, components, and devices is a practice that is quickly being adopted by the electrical engineering community. Designing and optimizing these systems and components often requires a good understanding and appreciation of the static, low or high-frequency electromagnetic phenomena affecting them. This can occur on large scales, such as in power cables transmitting electricity from country to country, or on the nanometer scale of a semiconductor diode. Simulation lets the designer take these variables into account in one unified environment and helps reduce the time-to-market for these electrical systems.

## AC/DC Electromagnetics

Electrical devices come in many shapes and sizes and often have to connect and correlate with many other devices in an electrical system. These can include inductors, capacitors, coils, motors, and insulating material, where the parameters that must be measured and optimized to describe their property include inductance, capacitance, impedance, force, torque, and resistance. Doing this requires simulating the individual device's electric, magnetic, and electromagnetic fields in the low-frequency domain, and connecting these solutions to other devices within a system or circuit. Often, BH curves and other material nonlinearities must also be considered and included in the simulation.

#### Featured User Story

Enhancing Transmission Line Performance

POWER Engineers, Inc

#### Featured Model

E-core Transformer: A single phase transformer with multiple coil turns is modeled while including the material's nonlinear B-H curve and its connection to an external circuit.

#### Featured User Story

ABB Alamo

Simulate electric, magnetic, and electromagnetic fields with the: AC/DCモジュール

## Electro- and Magnetostatics

Conductors, insulators, and magnets are devices that are described by simulating the electrostatic and magnetostatic fields within and surrounding them. The current-carrying media for these applications can be thick or thin, and appropriate simulating techniques, such as thin shell formulations for direct currents, are required to achieve accurate results. Electromagnetic shielding is also an important phenomenon that needs to be considered when optimizing devices for electromagnetic compatibility (EMC) and interference (EMI).

#### Featured User Story

How Reclosers Ensure a Steady Supply of Power: It’s All in the Magnet

ABB AG

#### Featured User Story

MRI Tumor-Tracked Cancer Treatment

Cross Cancer Institute

#### Featured Model

Magnetic Signature of a Submarine: The magnetic signature of a submarine within the Earth's magnetic field is simulated using features that model magnetic shielding.

Electro- and Magnetostatics applications can be modeled with the: AC/DCモジュール

## Joule and Induction Heating

Whenever an electrical system conducts current, heat will be produced. Joule heating involves the direct application of current through the conductor, while induction heating involves an electromagnetically-induced eddy current in the device that is producing heat. Joule and induction heating can have both positive and negative effects, but in all situations, this effect should be understood and designed for through simulation. The change in temperature can alter the material’s conductivity, while thermal stresses can lead to material deformation and destruction.

#### Featured User Story

Current Transformer Design That Combines Finite Element Analysis and Electric Circuit Simulation

ABB AG

#### Featured User Story

Innovative Packaging Design for Electronics in Extreme Environments

Arkansas Power Electronics International

#### Featured User Story

Multiphysics Simulation Helps Miele to Optimize Induction Stove Designs

Miele

#### Featured User Story

Simulation Enables the Next Generation of Power Transformers and Shunt Reactors

Siemens

Joule and Induction Heating can be modeled with: AC/DCモジュール 伝熱モジュール

## Microwave and RF Engineering

RF and microwave devices, such as waveguides, antennas, filters, and cavities require accurately simulating their resonant behavior through solving Maxwell's equations for electromagnetic wave propagation. Specialized elements used in the discretization scheme together with appropriate preconditioning algorithms and direct or iterative solvers are used for simulating the often computationally-expensive systems. Sometimes, parallel processing on multicore computers is useful for simulating large models or running frequency sweeps to compute properties such as S-parameters, power dissipation, transmission, reflection, impedance, and electromagnetic field distributions.

#### Featured User Story

Picking the Pattern for a Stealth Antenna

Altran

#### Featured User Story

A 100-Fold Improvement in Lithography Resolution Realized with a 150-Year-Old “Perfect Imaging” System

#### Featured User Story

Scattering of Electromagnetic Waves by Particles

AltaSim Technologies

#### Featured Model

Wilkinson Power Divider: This example shows the simulation of a Wilkinson power divider, outperforms lossless T-junction and resistive dividers.

Microwave and RF Engineering simulation can be completed with the: RFモジュール

## Optics and Photonics

High-frequency electromagnetic wave phenomena propagating in structures that are long and large in comparison to their wavelengths are challenging to simulate. Devices of these types are typically used for optics and photonics applications, where even anisotropic, nonlinear, and metamaterial media may need to be considered. For these systems, which include optical fibers, bidirectional couplers, plasmonic devices, and laser beams, robust and accurate simulations often require special methods for the discretization of Maxwell's equations to compute the full transmission and reflection properties.

#### Featured User Story

Nanoresonators Get New Tools For Their Characterization

LABORATOIRE PHOTONIQUE, Numérique, et Nanosciences of the Université de Bordeaux

#### Featured User Story

Meeting High-speed Communications Energy Demands Through Simulation

Bell Labs Research

#### Featured Model

Self-Focusing of an Optical Beam: A nonlinear optical material has a refractive index dependent on a beam of light's intensity that lets it self-focus the beam.

Model Optics and Photonics with the: 波動光学モジュール

## Ray Optics

Electromagnetic wave propagation through systems that are several orders of magnitude larger than the wavelength can be efficiently simulated using a ray tracing approach. Rays may either propagate in straight lines through homogeneous media, undergoing reflection and refraction at boundaries, or they may follow curved paths through graded index materials. As the rays propagate, changes in ray intensity, polarization, and phase must often be analyzed. For high-powered laser applications, accurate treatment of the attenuation of rays in absorbing media and of the temperature variation and structural deformation in the surrounding domains is vital.

#### Featured Model

A Czerny-Turner monochromator uses a combination of mirrors and diffraction gratings to separate polychromatic light into its constituent monochromatic rays, each of which is focused at a different point on a detector.

#### Featured Model

High-powered rays are focused onto a target in this laser system model. As the rays pass through the lenses, thermal expansion and a temperature induced change in the refractive index cause the focus of the beam to be shifted away from the target.

#### Featured Model

Caustic surfaces are explored in this model of the Vdara® hotel. During specific times of the day at specific times of the year, solar radiation was reflected off the curved surface of the hotel and focused at certain locations surrounding the pool.

Ray Optics can be modeled with: 光線光学モジュール

## RF and Microwave Heating

Electric energy losses in RF and microwave components invariably result in the production of heat, which can sometimes be put to use in devices like microwave ovens and biomedical treatment. On the other hand, imposed heat from the environment can have effects on the electromagnetic properties of such devices, including waveguides, antennas, and filters. All such characteristics should be accounted for prior to the manufacturing and deployment of such devices. Often, such simulations require simultaneously solving for the electromagnetic wave behavior in the frequency domain and the heat transfer equation in the stationary- or time-domain.

#### Featured User Story

Doubling Beam Intensity Unlocks Rare Opportunities for Discovery at Fermi National Accelerator Laboratory

Fermi National Accelerator Laboratory

#### Featured Video (Tutorial)

Electromagnetic losses in a dielectric block (dielectric heating), placed inside a waveguide as well as in the waveguide walls, leads to an increase in temperature in this example of RF heating. As the electromagnetic properties are functions of temperature, this becomes a multiphysics problem.

RF and Microwave Heating can be simulated with the: RFモジュール 伝熱モジュール

## MEMS and Piezoelectric Devices

Simulations of microelectromechanical systems (MEMS) and piezoelectric devices require consideration of both the electric and mechanical aspects of these devices. Actuators, sensors, gyroscopes, and resonators are just some of the many microscale and nanoscale components that require the coupling of these two phenomena when modeled, often with other phenomena such as thin-film gas damping, anisotropic loss-factors for solid and piezo materials, anchor damping, and thermoelastic damping. This requires sophisticated techniques to provide analyses in the stationary and transient domains, as well as to perform fully-coupled eigenfrequency, quasi-static, and frequency response analyses. Find additional MEMS models and user stories by visiting the MEMS Showcase.

#### Featured User Story

Modeling Optimizes a Piezoelectric Energy Harvester Used in Car Tires

Siemens

#### Featured User Story

Gaining Insight into Piezoelectric Materials for Acoustic Streaming

SUNY Albany, NY, USA and SEMATECH, NY, USA

#### Featured Video (Tutorial)

For devices that perform electrical operations through the use of moving parts, it is necessary to simultaneously conduct both structural and electrical analyses. In this step-by-step instructional video, you will learn how the Electromechanics interface in COMSOL Multiphysics can be used to solve solid mechanics and electrostatic problems through simulation.

MEMS and Piezoelectric Devices can be modeled with the: MEMSモジュール

## Semiconductor Simulation

Simulating semiconductor devices, such as MOSFETs and MESFETs, Schottky diodes, and P-N junctions at the fundamental level involves solving the drift-diffusion equations to model the transport of electrons and holes. In order to do this, you often need to use mobility models that describe the scattering of carriers within the semiconductor material. Often, multiphysics effects can influence semiconductor performance, as residual thermal stresses are present after manufacturing, and a lot of devices generate heat. These affect the mobility and transport properties within semiconductors, and must be considered in the model.

#### Featured Model

MOSFET Transistor: The threshold voltage for a MOSFET is calculated and then the linear and saturation regions for the device are identified in this example.

#### Featured Model

GaN Based LED: Optimum operating conditions of an LED are obtained by calculating the emission intensity, spectrum, and efficiency as a function of current.

#### Featured Model

Bipolar Transistor: The output current-voltage characteristics of a bipolar transistor in the common-emitter configuration are calculated and the common-emitter current gain is computed in this example.

Simulate semiconductors with the: 半導体モジュール

## Plasma Physics

Low-temperature plasma sources and systems are highly nonlinear in that slight perturbations in either the chemical or electrical input can lead to large changes in the discharge characteristics. Simulating them requires considering contributions from fluid mechanics, chemical reaction engineering, physical kinetics, heat and mass transfer, and electromagnetics. Considering the coupled multiphysics aspects of plasma physics is the only way to simulate direct current discharges, inductively-coupled plasmas, and microwave plasmas.

#### Featured Model

Dielectric Barrier Discharge: This model simulates the electrical characteristics of a dielectric barrier discharge (DBD). A plasma is periodically formed in between two parallel dielectric plates, one of which is grounded and the other applied with a sinusoidal voltage.

Featured Model Documentation PDF

#### Featured Model

In-Plane Microwave Plasma: In this example, a wave is launched into reactor and an argon plasma is created. The wave is absorbed by the plasma which sustains the discharge.

Featured Model Documentation PDF

#### Featured Model

GEC ICP Reactor: This model investigates the electrical characteristics of the Gaseous Electronics Conference (GEC) reference cell for argon chemistry.

Featured Model Documentation PDF

## Start Designing and Modeling Electrical Systems and Devices

• Simulating the electromagnetic behavior of electrical systems, components, and devices allows you to design and optimize effectively and reduce time-to-market.
• COMSOL Multiphysics and its modules for electromagnetic simulation and electrical design simulation is the perfect platform for accomplishing this.
• See it in action and try it hands-on at one of our COMSOL workshops, then go home with a free trial copy.

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