Power System Blockset

Mutual Inductance

Implement a magnetic coupling between two or three windings.

Library

Elements

Description

The Mutual Inductance block implements a magnetic coupling between three separate windings. Specify the self resistance and inductance of each winding on the first three entries of the dialog box and the mutual resistance and inductance in the last entry.

The electrical model for this block is given below:

Dialog Box and Parameters

Winding 1 self impedance

The self resistance and inductance for the winding 1, in ohms () and henries (H).

Winding 2 self impedance

The self resistance and inductance for the winding 2, in ohms () and henries (H).

Winding 3 self impedance

The self resistance and inductance in ohms () and henries (H) for the winding 3. Set the Winding 3 self impedance parameter to 0 to implement a Mutual Inductance block with two windings; a new icon will be displayed:

Mutual impedance

The mutual resistance and inductance between windings, in ohms () and henries (H). If the mutual resistance and reactance are set to [0,0], the block will implement three separate inductances with no mutual coupling.

Measurements

Select Winding voltages to measure the voltage across the winding terminals.

Select Winding currents to measure the current flowing through the windings.

Select Winding voltages and currents to measure the winding voltages and currents.

Place a Multimeter block in your model to display the selected measurements during the simulation.

In the Available Measurement listbox of the Multimeter block, the measurements will identified by a label followed by the block name.

Measurement	Label
Winding voltages	u w1: , u w2: , u w3:
Winding currents	i w1: , i w2: , i w3:

Inputs and Outputs

The winding 1 is connected between input and output one of the Mutual Inductance block. The winding 2 is connected between input and output two and the winding 3, if defined, is connected between input and output three.

The input ports of the Mutual impedance block are at the same instantaneous polarity.

Limitations

Due to modeling constraints, the following restrictions apply:

Negative values are allowed for the self and mutual inductances as long as the self inductances are different from the mutual inductance.

Windings can be left floating (i.e not connected by an impedance to the rest of the circuit). The floating winding will be internally connected to the main circuit through a resistor. This invisible connection does not affect voltage and current measurements.

Example

Three coupled windings are used to inject a third harmonic voltage into a circuit fed at 60 Hz. This example is available in the psbmutual.mdl file.

Simulation produces the following load voltage waveform:

See Also
Linear Transformer, Saturable Transformer

Multimeter

Neutral