Saturable Transformers
Purpose
Single-phase transformers with two or three windings and core saturation.
Library
Nonlinear
Description

These transformers model two or three coupled windings on the same
core.
The core saturation characteristic is piece-wise linear and is modeled using the
Saturable Inductor. The magnetizing current
and flux
value pairs are
referred to the primary side. To model a transformer without saturation enter 1 as
the magnetizing current values and the desired magnetizing inductance
as the
flux values. A stiff Simulink solver is recommended if the iron losses are not
negligible, i.e.
is not infinite.
In the transformer symbol, the primary side winding is marked with a little circle.
The secondary winding is marked with a dot at the outside terminal, the tertiary
winding with a dot at the inside terminal.
Parameters and Dialog Box
-
Leakage inductance
- A vector containing the leakage inductance of the primary
side
, the secondary side
and, if applicable, the tertiary side
. The
inductivity is given in henries (H).
-
Winding resistance
- A vector containing the resistance of the primary winding
, the secondary winding
and, if applicable, the tertiary winding
,
in ohms (
).
-
No. of turns
- A vector containing the number of turns of the primary winding
, the secondary winding
and the tertiary winding
, if applicable.
-
Magnetizing current values
- A vector of positive current values in amperes (A)
defining the piece-wise linear saturation characteristic of the transformer legs.
The current values must be positive and strictly monotonic increasing. At least
one value is required.
-
Magnetizing flux values
- A vector of positive flux values in Vs defining the
piece-wise linear saturation characteristic. The flux values must be positive and
strictly monotonic increasing. The number of flux values must match the number
of current values.
-
Core loss resistance
- An equivalent resistance
representing the iron losses in
the transformer core. The value in ohms (
) is referred to the primary side.
-
Initial current
- A vector containing the initial currents on the primary side
,
the secondary side
and the tertiary side
, if applicable. The currents are
given in amperes (A) and considered positive if flowing into the transformer at
the marked terminals. The default is [0 0 0].