This function is a conceptual model which is used as a building block to create a wide variety of inductive and magnetic circuit models. This function is almost always expected to be used in conjunction with the LCOUPLE model to build up systems which mock the behavior of linear and nonlinear magnetic components. There are two fundamental modes of operation for the core model. These are the PWL mode (which is the default, and which is the most likely to be of use to you) and the HYSTERESIS mode. These are detailed below.
PWL Mode (mode = 1)
The core model in PWL mode takes as input a voltage which it treats as a
magnetomotive force (mmf) value. This value is divided by the total
effective length of the core to produce a value for the Magnetic Field
Intensity, H. This value of H is then used to find the corresponding Flux
Density, B, using the piecewise linear relationship described in the
H_array / B_array coordinate pairs. B is then multiplied by the
cross-sectional area of the core to find the Flux value, which is output as
a current. The pertinent mathematical equations are listed below:
H = mmf/L, where L = Length
Here H, the Magnetic Field
Intensity, is expressed in ampere-turns/meter.
B = f(H)
The B value is derived from a piecewise
linear transfer function described to the model via the
(H_array,B_array) parameter coordinate pairs. This transfer function does not
include hysteretic effects; for that, you would need to substitute a HYST
model for the core.
Φ = BA, where A = Area
The
final current allowed to flow through the core is equal to Φ. This value in
turn is used by the LCOUPLE model to obtain a value for the voltage
reflected back across its terminals to the driving electrical circuit.
HYSTERESIS Mode (mode = 2)
The core model in HYSTERESIS mode takes as input a voltage which it treats as a magnetomotive force (mmf) value. This value is used as input to the equivalent of a hysteresis code model block. The parameters defining the input low and high values, the output low and high values, and the amount of hysteresis are as in that model. The output from this mode, as in PWL mode, is a current value which is seen across the mc port.
Parameters
| Parameter | Description | Default |
|---|---|---|
| H_array | Magnetic field array. | 0 1 |
| B_array | Flux density array. | 0 1 |
| area | Cross-sectional area. | 1 |
| length | Core length. | 1 |
| input_domain | Input smoothing domain. | 0.01 |
| fraction | Smoothing fractional/abs switch (True,False). | TRUE |
| mode | Mode switch (PWL, HYST). | PWL |
| in_low | Input low value. | 0 |
| in_high | Input high value. | 1 |
| hyst | Hysteresis. | 0 |
| out_lower_limit | Output lower limit. | 0 |
| out_upper_limit | Output upper limit. | 1 |
 Nota: |
|---|
One final note to be made about the two core model modes is that certain parameters are available in one mode, but not in the other. In particular, the in_low, in_high, out_lower_limit, out_upper_limit, and hysteresis parameters are not available in PWL mode. Likewise, the H_array, B_array, area, and length values are unavailable in HYSTERESIS mode. The input_domain and fraction parameters are common to both modes (though their behavior is somewhat different; for explanation of the input_domain and fraction values for the HYSTERESIS mode, you should refer to the HYSTERESIS code model). |
Example
The following example shows the use of two lcouple models and one core model to produce a simple primary/secondary transformer.
