Main Content

Network Coupler (Voltage-Current)

Split network at an electrical connection

Since R2022a

expand all in page
  • Network Coupler (Voltage-Current) block

Libraries:
Simscape / Utilities / Network Couplers

Description

The Network Coupler (Voltage-Current) block provides a starting point for you to split a Simscape™ network into two coupled networks at an electrical connection. Use this block when Network 1 (as described in Naming Conventions) has series-connected inductors or current sources, but Network 2 does not.

This block changes the behavior of the system because it adds a first-order lag to break the algebraic loop.

Port 1 interface of the Network Coupler (Current-Voltage) block is implemented as a voltage source. Therefore, you cannot connect this port to a voltage loop, such as a set of series-connected voltage sources and capacitors, because this would cause an Index-2 topology (for more information, see Avoiding Numerical Simulation Issues). Port 2 interface is implemented as a current source. Therefore, you cannot connect this port to a series-connected inductor or current source because this would also cause an Index-2 topology.

To facilitate working with models that contain arrays of electrical nodes or three-phase connection, the Port 1 Interface and Port 2 Interface subsystems contain custom blocks, such as Controlled Voltage Source or Current Sensor. These custom blocks are based on the equivalent Foundation library blocks but are modified to support vectorized and three-phase electrical nodes. The source files for these custom blocks are located in the following namespace: 

matlabroot/toolbox/physmod/simscape/library/m/+foundation/+internal/+couplers/+electrical

where matlabroot is the MATLAB® root directory on your machine, as returned by entering 

matlabroot

at the MATLAB command prompt. The namespace contains source files for voltage and current sources and sensors, as well as a resistor and an electrical reference with array and three-phase support. You can use these blocks to customize your network coupler configuration.

Working with the Block on the Model Canvas

When you add the block to your model and double-click it, the Network Coupler (Voltage-Current) subsystem opens.

Network Coupler (Voltage-Current) subsystem diagram

The Port 1 Interface block contains the dynamics that break the algebraic loop. Double-click this block to set all of the Network Coupler (Voltage-Current) subsystem parameters and view the derived values.

The rate transition blocks are, by default, commented through. Uncomment them if at least one of the coupled networks is running fixed step.

Using the Derived Values to Estimate Block Parameters

On the Analysis tab of the Port 1 Interface block dialog box, the Derived values section contains the Calculated fastest trackable time constant (s) value, based on the impact of the coupler lag. If both networks are variable-step, then you specify the filter time constant directly, as a block parameter. If at least one of the networks is fixed-step, the block calculates the time constant automatically based on the sample times that you specify, and the Derived values section displays the Calculated filter time constant (s) value.

The Update button lets you recalculate the derived values after you change the parameters of the connected networks.

Examples

Configuring an EV Simulation for Multirate HIL

Configuring an EV Simulation for Multirate HIL

An electric vehicle model suitable for multirate Hardware-In-the-Loop (HIL) deployment. The example uses the Simscape™ Network Couplers Library to split the model into separate Simulink® subsystems that can be deployed at different sample rates. This allows you to run parts of the system (for example thermal components) with a slower sample time thereby reducing overall computational cost.

Ports

Conserving

expand all

If one of the coupled networks is running variable step, connect it to port 1 of the Network Coupler (Voltage-Current) block. If both networks are running fixed step, connect this port to the network with the smaller sample time. If both networks are running variable step, or fixed step with the same step size, then the block polarity does not matter.

If one of the coupled networks is running variable step, connect port 2 of the Network Coupler (Voltage-Current) block to the fixed-step network. If both networks are running fixed step, connect this port to the network with the larger sample time.

Parameters

expand all

Main

Select this check box when breaking connections between three-phase electrical ports. Because the top-level subsystem is unmasked, you need to select this check box both for Port 1 Interface and Port 2 Interface blocks. Selecting this check box disables the Electrical node array size parameter because ports 1 and 2 become three-phase electrical ports.

Specify the size of the electrical node array connected to the two electrical ports, 1 and 2. Because the top-level subsystem is unmasked, you need to set this parameter to the same value both for Port 1 Interface and Port 2 Interface blocks.

If you are breaking a regular electrical connection, leave the default value of 1 unchanged.

Dependencies

To enable this parameter, clear the Use three-phase electrical connections check box.

Select how the coupled networks are sampled:

  • Variable step at ports 1 and 2 — Both networks are variable-step.

  • Variable step at port 1 and fixed step at port 2 — Network 1 is variable-step and Network 2 is fixed-step.

  • Fixed step both ports with common sample time — Both networks are fixed-step, with the same step size.

  • Fixed step both ports with faster sampling at port 1 — Both networks are fixed-step, with different step sizes.

Specify the filter time constant, in seconds, to remove the algebraic loop.

Dependencies

To enable this parameter, set the Sampling type parameter to Variable step at ports 1 and 2.

Specify sample time for Network 1, in seconds.

Dependencies

To enable this parameter, set the Sampling type parameter to Fixed step both ports with common sample time or Fixed step both ports with faster sampling at port 1.

Specify sample time for Network 2, in seconds.

Dependencies

To enable this parameter, set the Sampling type parameter to Variable step at port 1 and fixed step at port 2 or Fixed step both ports with faster sampling at port 1.

Select this check box to enable the prediction (discrete->continuous) algorithm. For more information, see Prediction and Smoothing.

Dependencies

To display this option, set the Sampling type parameter to Variable step at port 1 and fixed step at port 2.

Select this check box to enable the smoothing (continuous->discrete) algorithm. For more information, see Prediction and Smoothing.

Dependencies

To display this option, set the Sampling type parameter to Variable step at port 1 and fixed step at port 2.

Specify time constant, in seconds, for the first-order filter that the smoothing algorithm uses to remove unwanted high-frequency information.

Dependencies

To enable this parameter, select the Use smoothing when connecting variable step to fixed step check box.

Select this check box to enable the prediction (slow->fast) algorithm. For more information, see Prediction and Smoothing.

Dependencies

To display this option, set the Sampling type parameter to Fixed step both ports with faster sampling at port 1.

Select this check box to enable the smoothing (fast->slow) algorithm. For more information, see Prediction and Smoothing.

Dependencies

To display this option, set the Sampling type parameter to Fixed step both ports with faster sampling at port 1.

The smoothing algorithm works by averaging the last N samples. You specify N by using this parameter.

Dependencies

To enable this parameter, select the Use smoothing when connecting fast to slow sample times check box.

Analysis

For information on how to use the Derived values section, see Using the Derived Values to Estimate Block Parameters.

Initial Conditions

Specify initial condition for the current transmitted by the coupler, in A.

Specify initial condition for the voltage across the coupler, in V.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2022a

expand all

See Also

| | |

Topics