.. include:: /project-links.txt
.. include:: /abbreviation.txt


#############
 Transformer
#############

.. getthecode:: Transformer.py
    :language: python3
    :hidden:
    :notebook:


.. code-block:: py3

    
    from PySpice.Spice.Netlist import SubCircuitFactory
    from PySpice.Unit import *
    
    
    class Transformer(SubCircuitFactory):
    
        __name__ = 'Transformer'
        __nodes__ = ('input_plus', 'input_minus',
                     'output_plus', 'output_minus')
    
    
        def __init__(self,
                     turn_ratio,
                     primary_inductance=1@u_H,
                     copper_resistance=1@u_Ω,
                     leakage_inductance=1@u_mH,
                     winding_capacitance=20@u_pF,
                     coupling=.999,
                 ):
    
            super().__init__()
    
            # For an ideal transformer you can reduce the values for the flux leakage inductances, the
            # copper resistors and the winding capacitances. But
            if copper_resistance <= 0:
                raise ValueError("copper resistance must be > 0")
            if leakage_inductance <= 0:
                raise ValueError("leakage inductance must be > 0")
    
            # primary_turns =
            # secondary_turns =
            # turn_ratio = primary_turns / secondary_turns
            # primary_inductance =
            # primary_inductance / secondary_inductance = turn_ratio**2
            secondary_inductance = primary_inductance / float(turn_ratio**2)
    
            # Primary
            self.C('primary', 'input_plus', 'input_minus', winding_capacitance)
            self.L('primary_leakage', 'input_plus', 1, leakage_inductance)
            primary_inductor = self.L('primary', 1, 2, primary_inductance)
            self.R('primary', 2, 'output_minus', copper_resistance)
    
            # Secondary
            self.C('secondary', 'output_plus', 'output_minus', winding_capacitance)
            self.L('secondary_leakage', 'output_plus', 3, leakage_inductance)
            secondary_inductor = self.L('secondary', 3, 4, secondary_inductance)
            self.R('secondary', 4, 'output_minus', copper_resistance)
    
            # Coupling
            self.CoupledInductor('coupling', primary_inductor.name, secondary_inductor.name, coupling)