RLC (Three-Phase)

Three-phase impedance

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Libraries:
Simscape / Electrical / Passive / RLC Assemblies

Description

The RLC (Three-Phase) block models a three-phase impedance with two three-phase connections. Each of the three identical impedance components can include any combination of a resistor (R), capacitor (C), and inductor (L), connected in series or in parallel.

Define the values for the R, L, and C components by specifying the appropriate block parameters. Do not set the parameter values to zero or infinity to remove terms. Instead, select the correct option for the Component structure parameter.

For certain combinations of R, L, and C, for some circuit topologies, you should specify parasitic resistance or conductance values that help the simulation to converge numerically. These parasitic terms help create a small parallel resistive path for an inductor and a small series resistance for a capacitor.

Faults

Since R2024b

To model a fault in the RLC (Three-Phase) 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 RLC (Three-Phase) block allows you to represent one or more faulted phases. The block models the faulted phase as a resistor. To specify the value of the faulted resistance, use the Faulted resistance parameter.

For example, this diagram shows the equivalent circuit of three-phase inductor branch.

When you add a branch fault and you set the Faulted phase parameter to Phase a, this diagram shows the equivalent circuit of the faulted three-phase inductor branch.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see System Scaling by Nominal Values.

For this block, the Initial Targets and Nominal Values settings are visible only if, in the Main section, you do not set the Component structure parameter to R.

Examples

Power-Loss Analysis of a Three-Phase Rectifier

Perform a power-loss analysis using the ee_getPowerLossSummary function and the power_dissipated variable. The Rectifier contains six Diode blocks. Diodes D1, D2, D4, and D5 each dissipate, on average, 52.19 W over the course of the 0.5 second simulation. Diodes D3 and D6 each dissipate an average of 52.22 W for the same time period because they experience a 340 W transient power-dissipation spike due to DC-load capacitor charging before t = 1e-3 s. For each diode, the average power dissipated when the rectifier is operating in steady-state, t = 0.4 to 0.5 s, is 52.19 W.

• Open Model

Three-Phase Asynchronous Machine Starting

Model a wye-delta starting circuit for an induction machine. When the supply is connected to the machine via switch S1, switch S2 is initially off resulting in the machine being connected in a wye configuration. Once the machine is close to synchronous speed, switch S2 is operated thereby reconnecting the machine in a delta configuration. The higher impedance seen by the supply when the motor is in wye configuration reduces the starting current, and causes less disruption to other connected loads.

• Open Model

Ports

Conserving

~1 — Three-phase port

electrical

Composite three-phase port.

For more information about composite and expanded three-phase ports, see Three-Phase Ports.

Dependencies

To enable this port, set Electrical connection to Composite three-phase ports.

~2 — Three-phase port

electrical

Composite three-phase port.

For more information about composite and expanded three-phase ports, see Three-Phase Ports.

Dependencies

To enable this port, set Electrical connection to Composite three-phase ports.

a1 — a-phase

electrical

Electrical conserving port associated with the a-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

b1 — b-phase

electrical

Electrical conserving port associated with the b-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

c1 — c-phase

electrical

Electrical conserving port associated with the c-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

a2 — a-phase

electrical

Electrical conserving port associated with the a-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

b2 — b-phase

electrical

Electrical conserving port associated with the b-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

c2 — c-phase

electrical

Electrical conserving port associated with the c-phase.

Dependencies

To enable this port, set Electrical connection to Expanded three-phase ports.

Parameters

Main

Electrical connection — Whether to model composite or expanded three-phase ports

Composite three-phase ports (default) | Expanded three-phase ports

Since R2024b

Whether to model composite or expanded three-phase ports.

Composite three-phase ports represent three individual electrical conserving ports with a single block port. You can use composite three-phase ports to build models that correspond to single-line diagrams of three-phase electrical systems.

Expanded three-phase ports represent the individual phases of a three-phase system using three separate electrical conserving ports.

Component structure — Desired component combination

R (default) | L | C | Series RL | Series RC | Series LC | Series RLC | Parallel RL | Parallel RC | Parallel LC | Parallel RLC

Select the desired combination of a resistor (R), capacitor (C), and inductor (L), connected in series or in parallel.

Resistance — Resistance

1 Ohm (default) | positive scalar

Resistance of each of the line impedances.

Dependencies

To enable this parameter, set Component structure to either R, Series RL, Series RC, Series RLC, Parallel RL, or Parallel RC.

Inductance — Inductance

1e-3 H (default) | positive scalar

Inductance of each of the line impedances.

Dependencies

To enable this parameter, set Component structure to either L, Series RL, Series LC, Series RLC, Parallel RL, or Parallel LC.

Capacitance — Capacitance

1e-6 F (default) | positive scalar

Capacitance in each of the line impedances.

Dependencies

To enable this parameter, set Component structure to either C, Series RC, Series LC, Series RLC, Parallel RC, or Parallel LC.

Parasitics

Parasitic series resistance — Parasitic series resistance

0 Ohm (default) | nonnegative scalar

Series resistance value added to all instances of capacitors in the load.

Dependencies

To enable this parameter, set Component structure to either C, Parallel RC, or Parallel LC.

Parasitic parallel conductance — Parasitic parallel conductance

0 1/Ohm (default) | nonnegative scalar

Parallel conductance value added across all instances of inductors in the load. This parameter represents small parasitic effects.

If you set Component structure to either Series RL, Series LC, or Series RLC, the parasitic parallel conductance is connected across the full branch of the block.

Dependencies

To enable this parameter, set Component structure to either L, Series RL, Series LC, or Series RLC.

Faults

To modify the faults, create a fault and, in the block dialog box, click Open fault properties. To open the faults, in the Property Inspector, click the Fault behavior link.

Branch fault — Option to add branch fault

Add fault

Since R2024b

Option to add a branch fault in the RLC (Three-Phase) block.

To add a fault, click the Add fault hyperlink.

Faulted phase — Option to specify faulted phase

Phase a (default) | Phase b | Phase c | Phase a and b | Phase b and c | Phase c and a | Phase a, b and c

Since R2024b

Option to specify the faulted phase of the RLC (Three-Phase) block. You can specify one or more faulted phases.

Dependencies

To enable this parameter, add a fault to the RLC (Three-Phase) block by clicking the Add fault hyperlink in the Branch fault parameter.

Faulted resistance — Resistance of faulted impedance components

0.01 Ohm (default) | positive scalar

Since R2024b

Resistance of the faulted impedance components.

Dependencies

To enable this parameter, add a fault to the RLC (Three-Phase) block by clicking the Add fault hyperlink in the Branch fault parameter.

Extended Capabilities

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

Version History

Introduced in R2013b

R2024b: Model branch faults

You can now model one or more faulted phases. The block models the faulted phase as a resistor. To specify the value of the faulted resistance, use the Faulted resistance parameter.

R2024b: The Modeling Option parameter has changed

The Modeling option parameter has been replaced with the Electrical connection parameter inside the Main section in the block dialog box or Property Inspector.

If a model you created in an earlier release contains this block, the software automatically sets the value of the Electrical connection parameter to the value you specified for the Modeling option parameter.