Inductor with initial current

Symbol

Information

An inductor is a passive electrical component that stores energy in a magnetic field and resists changes in current. This model implements an inductor with an initial current (Ic), meaning it starts with a predefined current when the simulation begins.

The voltage-current relationship of an ideal inductor is given by:

\[ \begin{align}\begin{aligned}V = L \cdot \frac{dI}{dt}\\I(t=0) = I_c\end{aligned}\end{align} \]

Where: - \(V\) is the voltage across the inductor - \(I\) is the current through the inductor - \(L\) is the inductance (in Henrys) - \(I_c\) is the initial current

Ports

• p, n → Inductor terminals (voltage across & current through)

Symbol description

Field	Value
Symbol.name	InductorIc
Symbol.file	InductorIc.sym
Symbol.directory	Basic
Symbol.referance	L
Model.name	InductorIc
Model.file	InductorIc.py

Model

This model represents an inductor with an initial current. The voltage across the inductor is proportional to the rate of change of current.

Attributes:

• V (signal): Output voltage across the inductor.

• I (signal): Input current through the inductor.

• L (param): Inductance value in Henrys (default: 1.0e-3 H).

• Ic (param): Initial current in Amperes (default: 0 A).

Methods:

analog(): Defines the voltage-current relationship using the differential equation.

from pyams.lib import signal, model, param
from pyams.lib import voltage, current
from pyams.lib import ddt

class InductorIc(model):
    """
    Inductor model with initial current.
    """

    def __init__(self, p, n):
        # Signal declarations
        self.V = signal('out', voltage, p, n)
        self.I = signal('in', current, p, n)

        # Parameter declarations
        self.L = param(1.0e-3, 'H', 'Inductor value')
        self.Ic = param(0, 'A', 'Initial charge')

    def analog(self):
        """Defines the inductor's voltage-current relationship with initial current."""
        self.V += self.L * ddt(self.I, self.Ic)

Command syntax

To use this InductorIc model in a PyAMS simulation:

# Import the model
from pyams.models import InductorIc

# Define the inductor
# L1: instance name
# p, n: Inductor terminals
L1 = InductorIc(p, n)