Cable and Connectors

Cable and connectors with optional fault modeling

Since R2024b

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Libraries:
Simscape / Electrical / Connectors & References

Description

The Cable and Connectors block models a cable and connectors using resistors and inductors.

For most applications, you can connect two or more blocks together directly with physical connection lines. These connection lines are heavily idealized and have no resistance or inductance. If you need a simple physics-based model for an electrical cable or connectors, you can use a combination of Resistor blocks and Inductor blocks. Use the Cable and Connectors block instead, if you want to:

• Model multiple conductors in a single cable.

• Analyze cables with open-circuit faults.

• Analyze input or output connectors with short-circuit faults.

• Parameterize the conductors by defining the material and geometry instead of the resistance and inductance.

• Specify the gauge of the conductors using the American wire gauge (AWG) system.

Cable

The Cable and Connectors block models each conductor in the cable as a resistor. You can choose to also include an inductor in series with the resistor by selecting the Model cable inductance parameter. Clear this parameter to prioritize high simulation speeds. Select this parameter to prioritize accurate results.

To model a single conductor, clear the Model multiple conductors in cable parameter. To model multiple conductors, select the Model multiple conductors in cable parameter and specify the number of conductors using the Number of independent conductors in cable parameter.

The Cable and Connectors block has two ports that represent the electrical input and output. If you model a single conductor, the input and output ports are electrical conserving ports. If you model multiple conductors, the input and output ports are electrical array-of-nodes conserving ports. To connect the electrical array-of-nodes ports to the rest of your network, use an Array of Electrical Nodes block to act as a mux for the Simscape™ electrical domain by concatenating all input array of nodes into a single 1-D array. First, connect the input and output ports to the outConn port of separate Array of Electrical Nodes blocks. Then, set the Number of input connections parameter of the Array of Electrical Nodes blocks to the same numerical value as you set the Number of independent conductors in cable parameter of the Cable and Connectors block. This figure shows how to connect a Cable and Connectors block with three independent conductors in the cable.

Equations

The block assumes that the conductors in the cable are round wires and calculates the resistance of each conductor R using these equations [1],

$$R=\rho \frac{L}{\pi (r^2-{(r-\delta )}^2)}$$

$$\delta =\{\begin{array}{l}\frac{1}{\sqrt{\pi \mu \sigma f}}\text{ if }r\ge \frac{1}{\sqrt{\pi \mu \sigma f}}\\ r\text{ if }r\le \frac{1}{\sqrt{\pi \mu \sigma f}}\end{array}$$

where:

• ρ is the electrical resistivity of each conductor.

• L is the value of the Length of conductor parameter.

• r is the radius of the conductor.

• δ is the skin depth.

• μ is the magnetic permeability of the conductor.

• σ is the specific conductivity of the conductor.

• f is the rated frequency.

For DC current, there is no skin effect. Current spreads evenly over the cross-section of the conductor so δ = r. For high-frequency AC current, at full skin effect, current flows only on the surface of the conductor and δ = 0.

If you clear the Model skin effect parameter, f = 0. If you select the Model skin effect parameter, f is equal to the value of the Rated frequency parameter.

If you select the Model cable inductance parameter, the block calculates the inductance of each conductor L_DC using these equations [2],

$$L_{DC}=\frac{{\mu }_0}{2\pi }L\left(\ln \left(\frac{2L}{r}\right)-Y\right)$$

$$Y=\frac{1}{1+r\sqrt{\frac{\pi }{4}\mu \sigma f}}$$

where:

• μ₀ is the permeability of free space.

• Y is the current distribution constant.

The current distribution constant has a value between 0 and 1. For DC current, Y = 1. For high-frequency AC current Y approaches 0.

Connectors

The block models the connectors with resistors. The number of pins in the conductor is equal to the number of independent conductors in the cable. This figure shows the equivalent circuit for a three-pin input connector. The resistors labelled Ri model the contact resistance between each pin and the corresponding socket. The resistors labelled Gij model the inter-pin conductance for each pin pair (i,j).

Specify the resistance of resistors Ri using the Contact resistance between pin and sockets parameter. Specify the conductance of resistors Gij using the Conductance between pins parameter.

You do not always need to model connectors at both ends of the cable. For example:

• If you model a cable soldered directly to a printed circuit board (PCB), then it is more accurate not to model the connector at that end of the cable.

• If you model a cable with almost ideal connectors or you model an open-circuit fault in the cable, the inter-pin conductance and the contact resistance between the pins and sockets, in the connectors, have a negligible impact on the simulation results.

You can choose whether to model each connector by using the Model input connector and Model output connector parameters. If you do not need to model the connectors, choose not to model them to increase simulation speed.

Model Faults

To model a fault in the Cable and Connectors block, in the Faults section, click the Add fault hyperlink next to the fault that you want to model. In the Add Fault window, specify the fault properties. For more information about fault modeling, see Fault Behavior Modeling and Fault Triggering.

The Cable and Connectors block models electrical faults as an instantaneous change in the conductance of the cable or connectors. You can model an open-circuit fault in the cable or a short-circuit fault in the connectors.

The block can trigger fault events:

• At a specific time.

• When the current or temperature exceeds the maximum permissible value for longer than a specific time interval.

If you want to trigger a fault at a specific time, in the Fault Inspector window, set Trigger type to Timed. If you want to determine whether a system fails and, if so, when it fails, in the Fault Inspector window, set Trigger type to Behavioral.

If you select the behavioral trigger, the component fails as soon as one of the trigger conditions is true.

When the cable fails in open-circuit, the conductance of the conductors changes to the value of the Open-circuit conductance parameter. If you model multiple conductors in the same cable, you can choose to trigger faults for all conductors or specify which conductors you want to fail. To trigger an open-circuit fault for all conductors, set Faultable conductors to Make all conductors faultable. To trigger an open-circuit fault for specific conductors only, set Faultable conductors to Specify faultable conductors and specify which conductors you want to fail using the Indices of faultable conductors parameter.

When an input or output connector short circuits, the inter-pin conductance of pin pairs changes to the value of the Short-circuit conductance of faulted input connector or Short-circuit conductance of faulted output connector parameters. To trigger a short-circuit fault for all pin pairs, set Faultable pin pairs to Make all pin pairs faultable. To trigger a short-circuit fault for specific pin pairs only, set Faultable conductors to Specify faultable conductors and specify which conductors you want to fail using the Matrix of faultable pin pairs parameter. Each row of this matrix defines a pair of pins by their indices. For example, to enable a short circuit fault between pins 1 and pin 2, add the row 1,2; to the matrix.

Ports

Conserving

input — Input

electrical | electrical array-of-nodes

Electrical conserving port or electrical array-of-nodes conserving port associated with the input connector terminal.

If you clear the Model multiple conductors in cable parameter, this port is an electrical conserving port.

If you select the Model multiple conductors in cable parameter, this port is an electrical array-of-nodes conserving port. Connect the input port to the outConn port of an Array of Electrical Nodes block. Set the Number of input connections parameter parameter of the Array of Electrical Nodes block to the same numerical value as the Number of independent conductors in cable parameter of the Cable and Connectors block.

output — Negative terminal

electrical | electrical array-of-nodes

Electrical conserving port or electrical array-of-nodes conserving port associated with the output connector terminal.

If you clear the Model multiple conductors in cable parameter, this port is an electrical conserving port.

If you select the Model multiple conductors in cable parameter, this port is an electrical array-of-nodes conserving port. Connect the output port to the outConn port of an Array of Electrical Nodes block. Set the Number of input connections parameter parameter of the Array of Electrical Nodes block to the same numerical value as the Number of independent conductors in cable parameter of the Cable and Connectors block.

H — Thermal mass

thermal

Thermal conserving port associated with the thermal mass.

Dependencies

To enable this port, clear the Model thermal effects parameter.

Parameters

To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Main

Model multiple conductors in cable — Option to model multiple conductors

Off (default) | On

Option to model multiple conductors in the cable.

Number of independent conductors in cable — Number of independent conductors in cable

3 (default) | finite positive scalar

Number of independent conductors in cable.

Dependencies

To enable this parameter, select the Model multiple conductors in cable parameter.

Model input connector — Option to model input connector

On (default) | Off

Option to model an input connector.

Model output connector — Option to model output connector

On (default) | Off

Option to model an output connector.

Cable

Conductor material — Conductor material

Copper (default) | Annealed copper | Aluminum | Silver | Gold | Custom

Conductor material. This parameter determines the electrical conductivity and magnetic permeability of the material. To specify your own values for material properties, set this parameter to Custom.

Electrical conductivity of material — Electrical conductivity of material

5.96e7 S/m (default) | nonnegative scalar

Electrical conductivity of the material.

Dependencies

To enable this parameter, set Conductor material to Custom.

Length of conductor — Length of conductor

1 m (default) | positive scalar

Length of each conductor.

Gauge of each conductor — Gauge of conductor in AWG system

Custom (default) | AWG1 | AWG2 | ...

Gauge of each conductor, specified in the American wire gauge (AWG) system. Choose a value from AWG1 to AWG40.

To specify the gauge in length units, set this parameter to Custom and specify the value for the Conductor diameter parameter.

Conductor diameter — Gauge of each conductor in length units

0.5 mm (default) | positive scalar

Gauge of each conductor, specified in length units.

Dependencies

To enable this parameter, set Gauge of each conductor to Custom.

Model cable inductance — Option to model cable inductance

Off (default) | On

Option to model the inductance of the cable.

Clear this parameter to prioritize high simulation speeds.

Select this parameter to prioritize accurate results.

Model skin effect — Option to model skin effect

Off (default) | On

Option to model the skin effect.

Rated frequency — Rated frequency

50 Hz (default) | nonnegative scalar

Rated frequency.

Dependencies

To enable this parameter, select the Model skin effect parameter.

Relative magnetic permeability of material — Relative magnetic permeability of material

1 (default) | positive scalar

Relative magnetic permeability of the material.

Dependencies

To enable this parameter, set Conductor material to Custom.

Connectors

Contact resistance between pins and sockets — Contact resistance between pins and sockets

1 Ohm (default) | positive scalar

Contact resistance between the pins and sockets.

Dependencies

To enable this parameter, select the Model input connector or Model output connector parameter.

Conductance between pins — Conductance between pins

1e-12 S (default) | positive scalar

Conductance between the pins.

Dependencies

To enable this parameter:

• Select the Model input connector or Model output connector parameter.

• Select the Model multiple conductors in cable parameter.

Thermal

Model thermal effects — Option to model thermal effects

Off (default) | On

Option to model thermal effects. Select this parameter to enable the H port.

Resistance temperature coefficient — Resistance temperature coefficient

1e-6 1/K (default) | nonnegative scalar

Resistance temperature coefficient.

Dependencies

To enable this parameter, select the Model thermal effects parameter.

Measurement temperature — Measurement temperature

298.15 K (default) | scalar

Measurement temperature. This is the temperature at which you quote the value for the Resistance temperature coefficient parameter.

Dependencies

To enable this parameter, select the Model thermal effects parameter.

Thermal mass of each conductor — Thermal mass of each conductor

0.1 J/K (default) | positive scalar

Thermal mass of each conductor.

Dependencies

To enable this parameter, select the Model thermal effects parameter.

Thermal mass of each connector pin — Thermal mass of each connector pin

0.1 J/K (default) | positive scalar

Thermal mass of each connector pin.

Dependencies

To enable this parameter, select the Model thermal effects parameter.

Faults

Inter-pin short circuit in input connector fault — Option to add inter-pin short circuit in input connector fault

Add fault (default)

Option to add an inter-pin short circuit fault to the input connector of the Cable and Connectors block.

To add a fault, click the Add fault hyperlink.

Dependencies

To enable this parameter, select the Model multiple conductors in cable and Model input connector parameters.

Inter-pin short circuit in output connector fault — Option to add inter-pin short circuit in output connector fault

Add fault (default)

Option to add an inter-pin short circuit fault to the output connector of the Cable and Connectors block.

To add a fault, click the Add fault hyperlink.

Dependencies

To enable this parameter, select the Model multiple conductors in cable and Model output connector parameters.

Open-circuit fault — Option to add open-circuit fault

Add fault (default)

Option to add an open-circuit fault to the conductors in the cable of the Cable and Connectors block.

To add a fault, click the Add fault hyperlink.

Maximum permissible current — Maximum permissible current

inf A (default) | positive scalar

Upper load-current threshold for an open-circuit fault.

Dependencies

To enable this parameter:

• Add an open-circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Open-circuit fault parameter.

• In the Fault Inspector window, set Trigger Type to Behavioral.

This parameter appears in the Trigger section of the Fault Inspector window. For more information, see Set Fault Triggers.

Maximum permissible temperature — Maximum permissible temperature

inf degC (default) | scalar

Upper temperature threshold for an open-circuit or short-circuit fault.

Dependencies

To enable this parameter:

• Select the Model thermal effects parameter, in the Thermal settings.

• Add a fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in input connector fault, Inter-pin short circuit in output connector fault, or Open-circuit fault parameter.

• In the Fault Inspector window, set Trigger Type to Behavioral.

This parameter appears in the Trigger section of the Fault Inspector window. For more information, see Set Fault Triggers.

Time to fail when exceeding current — Time to fail when exceeding current

1 s (default) | positive scalar

Amount of time that the current must continuously exceed the maximum permissible current before a behavioral fault is triggered.

Dependencies

To enable this parameter:

• Add an open-circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Open-circuit fault parameter.

• In the Fault Inspector window, set Trigger Type to Behavioral.

This parameter appears in the Trigger section of the Fault Inspector window. For more information, see Set Fault Triggers.

Time to fail when exceeding temperature — Time to fail when exceeding temperature

1 s (default) | positive scalar

Amount of time that the temperature must continuously exceed the maximum permissible temperature before a behavioral fault is triggered.

Dependencies

To enable this parameter:

• Add a fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in input connector fault, Inter-pin short circuit in output connector fault, or Open-circuit fault parameter.

• In the Fault Inspector window, set Trigger Type to Behavioral.

This parameter appears in the Trigger section of the Fault Inspector window. For more information, see Set Fault Triggers.

Trigger fault at time — Time before entering faulted state

0 s (default) | nonnegative scalar

Simulation time at which the block enters the faulted state.

Dependencies

To enable this parameter, in the Fault Inspector window, set Trigger Type to Timed.

This parameter appears in the Trigger section of the Fault Inspector window. For more information, see Set Fault Triggers.

Short-circuit conductance of faulted input connector — Short-circuit conductance of faulted input connector

1e9 S (default) | nonnegative scalar

Short-circuit conductance of a faulted input connector.

Dependencies

To enable this parameter, add a fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in input connector fault parameter.

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Short-circuit conductance of faulted output connector — Short-circuit conductance of faulted output connector

1e9 S (default) | nonnegative scalar

Short-circuit conductance of a faulted output connector.

Dependencies

To enable this parameter, add a fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in output connector fault parameter.

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Faultable pin pairs — Faultable pin pairs

Make all pin pairs faultable (default) | Specify faultable pin pairs

Option to make all pin pairs faultable or to specify the faultable pin pairs.

Dependencies

To enable this parameter:

• Select the Model multiple conductors in cable parameter.

• Select the Model input connector or Model output connector parameters.

• Add an inter-pin short circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in input connector fault parameter or Inter-pin short circuit in output connector fault parameter.

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Matrix of faultable pin pairs — Faultable pin pairs

[1,2;1,3] (default) | matrix

Faultable pin pairs, specified as an N-by-2 matrix where N is the number of faultable pin pairs and each row defines a pair of pins by their indices. For example, to enable a short circuit fault between pins 1 and pin 2, add the row 1,2; to the matrix. When a short-circuit fault triggers, the inter-pin conductance changes only for the pin pairs you specify.

Dependencies

To enable this parameter:

• Select the Model multiple conductors in cable parameter.

• Select the Model input connector or Model output connector.

• Add an inter-pin short circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Inter-pin short circuit in input connector fault or Inter-pin short circuit in output connector fault parameter.

• Set Faultable pin pairs to Specify faultable pin pairs

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Open-circuit conductance — Open circuit conductance

1e-5 S (default) | positive scalar

Open-circuit conductance of a faulted conductor in the cable.

Dependencies

To enable this parameter, add an open-circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Open-circuit fault parameter.

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Faultable conductors — Faultable conductors

Make all conductors faultable (default) | Specify faultable conductors

Option to make all conductors faultable or to specify the faultable conductors.

Dependencies

To enable this parameter:

• Select the Model multiple conductors in cable parameter.

• Add an open-circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Open-circuit fault parameter.

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

Indices of faultable conductors — Indices of faultable conductors

[1,2] (default) | vector

Indices of faultable conductors. When an open-circuit fault triggers, the conductance changes only for the conductors with the indices that you specify.

Dependencies

To enable this parameter:

• Select the Model multiple conductors in cable parameter.

• Add an open-circuit fault to the Cable and Connectors block by clicking the Add fault hyperlink in the Open-circuit fault parameter.

• Set Faultable conductors to Specify faultable conductors

After you create the fault, you can change the properties in the Fault Inspector window. When you open a block that has a fault, the Open Fault Inspector hyperlink appears instead of the Add fault hyperlink. For an example that shows how to include faults, see Analyze a DC Armature Winding Fault.

References

[1] Keller, R. B. “Skin Effect.” In Design for Electromagnetic Compatibility--In a Nutshell, by Reto B. Keller, 135–43. Cham: Springer International Publishing, 2023. https://doi.org/10.1007/978-3-031-14186-7_10.

[2] Rosa, E. B. “The Self and Mutual Inductances of Linear Conductors.” In Bulletin of the Bureau of Standards 4, no. 2 (January 1908): 301. https://doi.org/10.6028/bulletin.088.

Extended Capabilities

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

Version History

Introduced in R2024b