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Smooth air-gap synchronous machine with main flux saturation.
Electrical / Machines
The Round Rotor Synchronous Machine models main flux saturation by means of a function. The model is implemented with machine equations in the rotor reference frame (Park transformation). Since the machine terminals have current-source characteristic, no external inductors may be connected. They must be included in the leakage inductances. The machine can be used with both the continuous and the discrete state-space method.
The machine operates as a motor or generator; the sign of the mechanical torque determines the mode of operation (positive for motoring, negative for generating). All electrical variables and parameters are viewed from the stator side. In the component icon, phase a of the stator winding and the positive pole of the field winding are marked with a dot.
In order to inspect the implementation, please select the component in your circuit and choose Look under mask from the Edit menu. If you want to make changes, you must first choose Break library link and then Unprotect, both from the Edit menu.
The electrical system of the machine model is implemented with state-variable
equations that are derived from the equivalent circuit in the rotor reference frame.
The value of the main flux inductance is not constant but depends on the main
flux linkage
as illustrated in the
diagram. For flux linkages
far
below the transition flux
, the relationship between flux and current is almost
linear and determined by the unsaturated magnetizing inductance
. For large
flux linkages the relationship is governed by the saturated magnetizing inductance
.
defines the knee of the transition between unsaturated and
saturated main flux inductance. The tightness of the transition is defined
with the form factor
. If you do not have detailed information about the
saturation characteristic of your machine,
is a good starting value. The
function
plsaturation(Lm0, Lmsat, PsiT, fT)
plots the main flux vs. current curve and the magnetizing inductance vs. current curve for the parameters specified.
The model accounts for steady-state cross-saturation, i.e. the steady-state magnetizing inductances along the d-axis and q-axis are functions of the currents in both axes. In the implementation, the stator currents, the field current and the main flux linkage are chosen as state variables. With this type of model, the representation of dynamic cross-saturation can be neglected without affecting the machine's performance. The computation of the time derivative of the main flux inductance is not required.
Electromagnetic torque:
Mechanical rotor speed :
Most parameters for the Salient Pole Synchronous Machine are also applicable to this round rotor machine. The following parameters are different:
Same as for the Salient Pole Synchronous Machine.
Most probe signals for the Salient Pole Synchronous Machine are also available with this machine. Only the following probe signal is different: