SIMetrix Cosimulation Interface

Interface Simulink signals and Simscape Electrical nodes with SIMetrix model

Since R2025a

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  • SIMetrix Cosimulation Interface block

Libraries:
Simscape / Electrical / Additional Components / Cosimulation

Description

The SIMetrix Cosimulation Interface block creates a virtual connection between Simulink® signals and Simscape™ Electrical™ nodes and a SIMetrix netlist. Use this block to run cosimulations using Simscape and SIMetrix. By running cosimulations, you can incorporate designs developed in different tools into a Simscape model. For example, you can:

  • Model electronics in SIMetrix using models provided by device manufacturers.

  • Design electrical, electromechanical, and other multidomain systems using Simscape.

  • Design control systems using Simulink.

Cosimulation can improve team integration. You can build a system-level model that models semiconductor devices with ideal switching using Simulink and Simscape. Then, to validate the model, you can run a cosimulation using detailed designs of the electronics developed in SIMetrix. You can also use cosimulation to test circuits developed in SIMetrix against a realistic load, such as a motor in Simscape Electrical.

Cosimulation is an alternative to the subcircuit2ssc function, which converts SPICE subcircuits to an equivalent Simscape component. Cosimulation is usually the better choice for SPICE models developed in SIMetrix. The subcircuit2ssc function is useful only to convert circuits with a small number of R, L, C, and transistor devices. Large networks of semiconductor devices are more challenging to simulate and only simulate reliably by using the SPICE simulation engine for which they were originally written.

To run cosimulations, you also need to use a Cosimulation Interface in your SIMetrix schematic. This figure shows how the Cosimulation Interface in SIMetrix exchanges information with the SIMetrix Cosimulation Interface block in Simscape.

Figure showing how SIMetrix and Simulink can exchange information. The SIMetrix circuit exchanges voltage and current values with the Cosimulation Interface in SIMetrix. The virtual connection between SIMetrix passes current values from the Cosimulation Interface in SIMetrix to the block in Simscape and passes voltage values from the block in Simscape to the Cosimulation Interface in SIMetrix. The block in Simscape exchanges voltage and current values with the Simscape Electrical circuit.

In your Simscape model, the SIMetrix Cosimulation Interface block represents the part of your electrical network that you want to simulate in SIMetrix. You can connect this block to a Simulink block diagram by using signal lines or to an electrical network in Simscape by using physical connection lines. You can also choose whether SIMetrix sends voltage or current values to Simscape.

You can build your SIMetrix schematic and Simscape model independently. However, the number, name, and type of the ports of the SIMetrix Cosimulation Interface block depend on the options you select for the Cosimulation Interface in SIMetrix. To prepare the models for cosimulation, you therefore need to update the SIMetrix schematic first. To use the SIMetrix Cosimulation Interface block in your Simscape model, you first need to save your SIMetrix schematic, with a predefined interface with Simulink, as a netlist:

  1. Build a schematic of the electronics that you want to simulate in SIMetrix.

  2. Create a Cosimulation Interface in the SIMetrix schematic — In the Command Shell, enter Simulink_create_interface_symbol.

  3. Configure the Cosimulation Interface and connect it to your circuit — How you do this depends on what information you want SIMetrix and Simscape to exchange. For more information about completing this step, see Create Virtual Connections.

  4. Convert the schematic into a netlist — In the SIMetrix Command Shell, enter netlist followed by the name of your netlist. For example, netlist yourNetlistName.net.

After you save your netlist in SIMetrix, you build the block diagram or electrical network that you want to simulate in Simscape. You then use the SIMetrix Cosimulation Interface block to create virtual connections between your SIMetrix and Simscape models. Specify the file path of the SPICE netlist using the Netlist file path parameter of the SIMetrix Cosimulation Interface block or click the Browse button to select the SPICE netlist using your system browser. Then, to build the input/output device, click the Build I/O button. This action creates the virtual connections between SIMetrix and Simscape and enables the correct ports in the SIMetrix Cosimulation Interface block.

You set the fixed rate at which SIMetrix provides output to Simulink, using the Sample time (s) parameter. In between sample times, SIMetrix runs with a variable step solver. You must set the Sample time (s) parameter to a value that it small enough for Simulink to capture the important dynamics from the SIMetrix simulation. This configuration, with a variable time step for the SIMetrix simulation sampled at a fixed rate in the Simulink simulation, means that cosimulation works most efficiently when you model the faster dynamics in SIMetrix and model the slower dynamics in Simulink or Simscape. For example, cosimulation works efficiently when you model a motor drive by modeling the power electronics in SIMetrix and modeling the motor and mechanical load in Simscape.

When you run the model, SIMetrix and Simscape simulate together. SIMetrix and Simscape can both store the results. You can visualize and postprocess the data using either software.

The SIMetrix Cosimulation Interface block supports SIMetrix Pro and SIMetrix Elite 9.1 and beyond.

Create Virtual Connections

The number, name, and type of the ports of the SIMetrix Cosimulation Interface block depend on the options you select for the Cosimulation Interface in SIMetrix. To create virtual connections, you need to understand these options.

The Configuration parameter determines whether SIMetrix sends information to or receives information from Simulink or Simscape. The Input connections and Output connections parameters determine the nature of this information. You can exchange values of current, voltage, or both. You can also choose whether to measure voltage values relative to ground or to model two separate connections. The Number of ports parameter determines the number of ports of the Cosimulation Interface in SIMetrix.

You can set the Configuration parameter to:

  • Input only — SIMetrix sends voltage or current values as input to Simulink. Selecting this option enables the Input connections parameter. The corresponding SIMetrix Cosimulation Interface block has a Simulink output port.

  • Output only — SIMetrix receives voltage or current values as output from Simulink. Selecting this option enables the Output connections parameter. The corresponding SIMetrix Cosimulation Interface block has a Simulink input port.

  • Combined Input Output V/I or I/V — SIMetrix sends voltage or current values to Simscape and receives current or voltage values from Simscape. Selecting this option enables the Output connections parameter. SIMetrix automatically selects the appropriate value for the Input connections parameter. The corresponding SIMetrix Cosimulation Interface block has one or two Simscape conserving ports.

You can set the Input connections or Output connections parameter to:

  • Single-ended Voltage

  • Differential Voltage

  • Single-ended Current

  • Differential Current

Choosing Single-ended Voltage or Single-ended Current effectively grounds and hides the negative terminals.

If you set the Configuration parameter to Combined Input Output V/I or I/V, the input and output configuration must have the same number of ports and have the same type of connection, either single-ended or differential. If you also set the Output Connections parameter to Single-ended Voltage or Single-ended Current, the SIMetrix Cosimulation Interface block has one conserving port. If you set the Output Connections parameter to Differential Voltage or Differential Current, the SIMetrix Cosimulation Interface block has two conserving ports.

This table summarizes how SIMetrix exchanges information with Simulink or Simscape. The table also shows the types of ports that the corresponding SIMetrix Cosimulation Interface has and the names of those ports.

Configuration Parameter ValueInput Connections Parameter ValueOutput Connections Parameter ValueInformation ExchangeSIMetrix Cosimulation Interface Block Port TypeSIMetrix Cosimulation Interface Simulink Block Diagram
Input OnlySingle-ended VoltageN/ASIMetrix sends voltage values as input to Simulink.Simulink output port U1

Simulink block diagram of a block with one output port, U1. The port connects to an Outport block through a Simulink signal line.

Differential VoltageN/A
Single-ended CurrentN/ASIMetrix sends current values as input to Simulink.
Differential CurrentN/A
Output OnlyN/ASingle-ended VoltageSIMetrix receives voltage values as output from Simulink.Simulink input port U1

Simulink block diagram of a block with one input port, U1. The port connects to an Inport block through a Simulink signal line.

N/ADifferential Voltage
N/ASingle-ended CurrentSIMetrix receives current values as output from Simulink.
N/ADifferential Current
Combined Input Output V/I or I/VSingle-ended CurrentSingle-ended VoltageSIMetrix sends current values to Simscape and receives voltage values from Simscape.Simscape conserving port U1V

Simscape network diagram of a block with one conserving port, U1V. The port connects to a Connection Port block through a physical connection line.

Differential CurrentDifferential VoltageSimscape conserving ports U1V+ and U1V-

Simscape network diagram of a block with two conserving ports, U1V+ and U1V-. The ports connect to Connection Port blocks through a physical connection lines.

Single-ended VoltageSingle-ended CurrentSIMetrix sends voltage values to Simscape and receives current values from Simscape.Simscape conserving port U1I

Simscape network diagram of a block with one conserving port, U1I. The port connects to a Connection Port block through a physical connection line.

Differential VoltageDifferential CurrentSimscape conserving ports U1I+ and U1I-

Simscape network diagram of a block with two conserving ports, U1I+ and U1I-. The ports connect to Connection Port blocks through a physical connection lines.

Note

The number, name, and type of the ports in this table always apply if you have a single Cosimulation Interface in SIMetrix. However, one SIMetrix Cosimulation Interface block corresponds to one SIMetrix schematic or netlist, not one Cosimulation Interface. You can build a SIMetrix Cosimulation Interface block with more ports and multiple port types by using multiple Cosimulation Interfaces in SIMetrix. SIMetrix labels each Cosimulation Interface Uk, where k is an integer between 1 and the number of Cosimulation Interfaces in the schematic. These numbers correspond to the numbers in the port names of the SIMetrix Cosimulation Interface block.

The Number of ports parameter defines the number of ports of the Cosimulation Interface in SIMetrix. This parameter does not affect the number of ports of the SIMetrix Cosimulation Interface block in Simscape. Instead, the port type changes to support the correct number of voltage or current values. If you set this parameter to 1:

  • Simulink input and output ports carry scalar signals.

  • Simscape ports are electrical conserving ports.

If you set this parameter to a value greater than 1:

  • Simulink input and output ports carry vector signals.

  • Simscape ports are electrical array-of-nodes conserving ports. You can connect the SIMetrix Cosimulation Interface block to your electrical network by using an Array Connection block.

Create Virtual Connections Between SIMetrix Schematics and Simscape Electrical Networks

To create connections between a SIMetrix schematic and a Simscape Electrical network, set the Configuration parameter of the Cosimulation Interface in SIMetrix to Combined Input Output V/I or I/V.

To model an inductive load or current source in Simscape, set the Output connections parameter to Single-ended Voltage or Differential Voltage. To model a capacitive load or voltage source in Simscape, set the Output connections parameter to Single-ended Current or Differential Current. To model a purely resistive load in Simscape, you can use any of these options.

This table shows simple examples of corresponding SIMetrix schematics and Simscape networks for cosimulation. The table also shows the equivalent electrical network modeled entirely in Simscape. The Inductor and Capacitor blocks in the Simscape networks represent any inductive or capacitive load, respectively.

GoalInput ConnectionsOutput ConnectionsExample SIMetrix Schematic for CosimulationExample Simscape Network for CosimulationEquivalent Simscape Network
Model an inductive load in SimscapeSingle-ended CurrentSingle-ended Voltage

SIMetrix schematic of a resistor connected to a Cosimulation Interface with one port

Simscape network diagram of a block with one conserving ports connected to an Inductor block

Simscape network diagram of a resistor and an inductor connected in a closed loop

Differential CurrentDifferential Voltage

SIMetrix schematic of a resistor connected to a Cosimulation Interface in with two ports in a closed loop

Simscape network diagram of a block with two conserving ports connected to an Inductor block in a closed loop

Model a capacitive load in SimscapeSingle-ended VoltageSingle-ended Current

SIMetrix schematic of a resistor connected to a Cosimulation Interface with one port

Simscape network diagram of a block with one conserving port connected to a Capacitor block

Simscape network diagram of a resistor and a capacitor connected in a closed loop

Differential VoltageDifferential Current

SIMetrix schematic of a resistor connected to a Cosimulation Interface in with two ports in a closed loop

Simscape network diagram of a block with two ports connected to a Capacitor block in a closed loop

Create Virtual Connections Between SIMetrix Schematics and Simulink Block Diagrams

To create virtual connections between a SIMetrix schematic and a Simulink block diagram, set the Configuration parameter of the Cosimulation Interface in SIMetrix to Input only or Output only. These figures show a simple example with both an input and an output.

Simulink block diagram of a block with an input and an output

SIMetrix schematic of a Cosimulation Interface with an input and an output

The Simulink input port, U1, sends the gate-emitter voltage signal to the IGBT in the SIMetrix schematic. This port corresponds to the U1 Cosimulation Interface in SIMetrix. To create the virtual connection, in the Cosimulation Interface set:

  • Configuration to Output only

  • Output connections to Differential Voltage

  • Number of ports to 1

The Simulink output port, U2, receives the single-ended collector voltage signal from the IGBT in SIMetrix. This port corresponds to the U2 Cosimulation Interface in SIMetrix. To create the virtual connection, in the Cosimulation Interface set:

  • Configuration to Input only

  • Input connections to Single-ended Voltage

  • Number of ports to 1.

Assumptions and Limitations

  • In SIMetrix, you can set the Configuration parameter of the Cosimulation Interface to:

    • Input only

    • Output only

    • Separate Input Output

    • Combined Input Output V/I or I/V

    The SIMetrix Cosimulation Interface block does not support the Separate Input Output option.

  • You cannot run cosimulations using a Simscape model with more than one SIMetrix Cosimulation Interface block.

  • The SIMetrix Cosimulation Interface block supports up to 16 ports.

Ports

Note

The SPICE netlist defines the name, type, and number of ports of the SIMetrix Cosimulation Interface block. To update the ports after changing the parameters of the Cosimulation Interface in SIMetrix, convert the schematic into a netlist and build the input/output device in Simscape. For more information, see the Description section.

Input

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Simulink input port that measures the voltage or current that Simulink sends to SIMetrix. The SIMetrix Cosimulation Interface block sends this signal to the kth Cosimulation Interface, Uk, in your SIMetrix model.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, the associated signal is a scalar. If you set the Number of ports parameter to a value greater than 1, the associated signal is a vector.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Output only.

Output

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Simulink output port that measures the voltage or current that SIMetrix sends to Simulink. The SIMetrix Cosimulation Interface block receives this signal from the kth Cosimulation Interface, Uk, in your SIMetrix model.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, the associated signal is a scalar. If you set the Number of ports parameter to a value greater than 1, the associated signal is a vector.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Input only.

Conserving

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Electrical conserving port associated with the positive terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape grounds and hides the corresponding negative terminal. Simscape sends voltage values to SIMetrix and receives current values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Single-ended Current.

Electrical conserving port associated with the positive terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape sends voltage values to SIMetrix and receives current values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Differential Current.

Electrical conserving port associated with the negative terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape sends voltage values to SIMetrix and receives current values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Differential Current.

Electrical conserving port associated with the positive terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape grounds and hides the corresponding negative terminal. Simscape sends current values to SIMetrix and receives voltage values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Single-ended Voltage.

Electrical conserving port associated with the positive terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape sends current values to SIMetrix and receives voltage values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Differential Voltage.

Electrical conserving port associated with the negative terminal of the kth Cosimulation Interface, Uk, in your SIMetrix model. Simscape sends current values to SIMetrix and receives voltage values from SIMetrix.

If you set the Number of ports parameter in the Cosimulation Interface in SIMetrix to 1, this port is an electrical conserving port. If you set the Number of ports parameter to a value greater than 1, this port is an electrical array-of-nodes conserving port.

Dependencies

To enable this port, in the Cosimulation Interface in SIMetrix, set the Configuration parameter to Combined Input Output V/I or I/V and set Output Connections to Differential voltage.

Parameters

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File path of the SPICE netlist.

Browse button. Click this button to select the SPICE netlist file using your system browser.

Build the input/output device. Click this button to create or update the virtual connections between the SIMetrix Cosimulation Interface block and your SIMetrix netlist.

Sample time, in seconds. This value describes the fixed rate at which SIMetrix provides output to Simulink. You must set this parameter to a value that it small enough for Simulink to capture the important dynamics from the SIMetrix simulation.

Version History

Introduced in R2025a

See Also

Functions

Simscape Blocks

External Websites