The Vizimag transformer design aid provides a free manual mode which calculates parameters of a transformer equivalent circuit, and a model mode where parameters such as flux coupling are calculated from a Vizimag simulation. The manual mode will remain working even when the trial period is over.
Using the Transformer Design Function
The Vizimag transformer design aid calculates the parameters in the transformer equivalent circuit;
Vp is the input voltage, which is assumed to be sinusoidal. Rp is the resistance and Lp the inductance of the primary winding. K is the coupling factor between primary and secondary (unity if there is no flux loss between the windings). Lp is the inductance and Rs the resistance of the secondary winding. RL is the load resistance. Ep is the actual voltage across the primary winding after losses, and Es is the voltage developed in the secondary winding, before losses due to load current flowing in the secondary circuit. Vs is the measured secondary voltage across the load. Not included are core hysteresis and eddy current losses (which would be modeled as a shunt resistor and inductor in the primary circuit), and saturation of the core.
Circuit equations
The effective primary resistance and reactance include the effect of the secondary loading (if any).
Secondary inductance
Mutual inductance
for the open circuit case
this reduces to
for the open circuit case this reduces to
Effective impedance
Primary current
Primary winding voltage
Secondary winding voltage
Secondary current
for the open circuit case
is zero.
Analysis modes
Two modes are available when the transformer design
icon is clicked
.
In manual mode the user must provide a value for the primary inductance, and the coupling coefficient is assumed to be unity. In model mode, a Vizimag model of the transformer is analyzed. From the model dimensions, turns and current the actual inductance is calculated from the flux, and the flux coupling coefficient will be calculated. Model requirements will be discussed later. The manual mode is available even in time expired trial software.
Manual mode
When the manual button is
clicked, the following panel appears:
A set of possible circuit conditions is suggested. Change them to the particular design needs. All the marked edit boxes must be filled in the primary circuit, but not the inductance, coupling coefficient or mutual inductance in the secondary. Then click the calculate button to work out the remaining circuit values. For no-load conditions leave the load resistor edit box blank. Enter figures in decimal or scientific notation.
Model mode
The model mode is used in conjunction with a Vizimag magnetic model. When the model button is clicked the following panel appears:
The primary and then the secondary coil of the model must be clicked to tell Vizimag which to use for analysis.
These panels are similar to those for the manual mode, except Vizimag has calculated the primary and secondary inductances, and the coupling coefficient, from the model. The model fixes the number of turns. Change other parameters as required and click calculate. It is also possible to select a round or square section coil. For no-load calculations leave the load resistor edit box blank. Click the reset button to restore the original values taken from the model.
Magnetic field software. Vizimag modelling software gives visualization of field lines and flux density.