Creating Electric Circuits

Electrical circuits are conducting loops of interconnected electrical components, such as batteries, power sources, resistors, and inductors. You specify the circuit elements and the connections between them to define the conducting path and account for mutual interactions.

You can create electric circuits using the Circuit Editor, or set them up directly in the simulation tree.

Using the Circuit Editor—The Circuit Editor provides a graphical interface for creating circuits. You can use simple drag and drop functions to create the necessary circuit elements and define connections between them. This method can be quicker and easier than setting up your circuits directly in the simulation tree.
See Circuit Editor Reference.
Using the simulation tree—You create the necessary circuit elements under the Circuit Elements node and define the connections under the Circuit Connections node.
See Using the Simulation Tree.

To define an electrical circuit, you create connections between circuit elements. It is possible to connect circuit elements in parallel and in series. In a series connection, the positive terminal of one circuit element is connected with the negative terminal of another. In a parallel connection, the circuit connection contains three or more terminals, depending on the layout of the circuit.

When you create connections in a circuit, the following conditions apply:

A battery module can be used once only in a simulation: you cannot use the same battery module in two or more circuits.
A program file can be used in multiple circuits.
The maximum number of grounded connections in a circuit is specified in the Number of Allowed Groundings property of the circuit. By default, this value is 1.

To create an electric circuit:

In the physics continuum, activate the following models:


Group Box	Model
Time	Implicit Unsteady
Material	Solid or Multi-Part Solid
Optional Models	Battery or Electromagnetism Circuit Model (selected automatically when the Battery model is activated)

The Circuits node is added to the simulation tree. This node contains a default circuit, Circuit 1. See Circuit Model Reference.

The Circuits node can contain multiple circuits, which can be independent or coupled. For example, you can use two coupled circuits to simulate a transformer, in which the change in magnetic energy in one circuit is the voltage source for another circuit. You can use multiple independent circuits when modeling multiple batteries in the same thermal environment, where each battery has its own load.

For each additional circuit that you want to add, right-click the Circuits node and select New.
The new [circuit] node is added under the Circuits node.
Select the [circuit] node and set the circuit properties.

You set the properties independently for each circuit. See Circuit Properties.

These settings are used by the Circuit Solver. See Circuit Solver.
Create the circuit elements and connections that you require:
- If you want to use the Circuit Editor, right-click the [circuit] node and select Open Circuit Editor.
  The Circuit Editor provides a graphical interface for creating and modifying circuits. Using the Circuit Editor to create circuit elements and connections can be quicker and easier than setting up your circuits directly in the simulation tree.
  See Using the Circuit Editor.
- If you want to use the simulation tree, see Using the Simulation Tree.
Set the circuit element properties. For each circuit element:
1. Select the Circuit Elements > [circuit element] node.
2. In the Properties panel, specify the appropriate values.
3. If necessary, specify the initial current or voltage.
See Circuit Element Properties.

Mutual inductance connections account for the mutual interaction between the inductances of the connected circuit elements. You can create mutual inductance connections between the following:

Two inductance elements. That is, any two scalar circuit elements that have the Load Type set to Inductance.
Two excitation coil circuit elements, when the Load Type of each element is set to Compound.

Create any necessary mutual inductance connections. For each connection:
1. Under the Circuit Elements node, multi-select the two inductance elements or the two excitation coil elements that you want to connect.
  You cannot create a mutual inductance connection between an inductance element and an excitation coil element.
2. Right-click any selected element and then click Create Mutual Inductance Connection.
  
  The new connection is added under the [circuit] > Mutual Inductance Connections node.
For each mutual inductance connection, specify the mutual inductance.
- For a connection between two inductance elements:
  Select the [circuit] > Mutual Inductance Connections > [mutual inductance connection] node and specify the Mutual Inductance property value.
- For a connection between two excitation coil elements:
  In the physics continua associated with the coil regions, activate the Excitation Coil Lumped Parameter model.
  Simcenter STAR-CCM+ automatically calculates the mutual inductance from the inductances of each coil region. See Excitation Coil Lumped Parameter Model Reference.

You can create current and voltage reports for specific circuit elements.

For each circuit element for which you want to create a report:
1. Right-click the Reports node, click New Report > Circuit Model, and then click the appropriate report type:
  - Circuit Element Current
  - Circuit Element Current Derivative
  - Circuit Element Voltage
  The corresponding node is added under the Reports node.
2. Select the new report node and set the Circuit Element property to specify the appropriate circuit element.
3. Set the remaining properties as required.
See Circuit Element Reports.

You can create additional reports for excitation coil elements.

For each excitation coil circuit element for which you want to create reports:
1. Right-click the [circuit] > Circuit Elements > [excitation coil] node and then click Create Reports.
  Four reports are created for the excitation coil circuit element and the corresponding nodes are added under the Reports node:
  - [excitation coil] Excitation Coil Conductor Resistance
  - [excitation coil] Magnetic Flux Linkage
  - [excitation coil] Magnetic Inductance
  - [excitation coil] Magnetic Motion Induced Voltage
2. For each report, select the new report node and set the appropriate properties.
See Excitation Coil Model Reference and Excitation Coil Lumped Parameter Model Reference.
Save the simulation.