Source code for diamondback.transforms.ComplexTransform
""" **Description**
A complex transform converts a three-phase real signal to a complex
signal, or converts a complex signal to a three-phase real signal, in
equivalent and reversible representations. A neutral condition is
specified.
Singleton.
.. math::
\gamma = \scriptsize{ \matrix{ 1 & \\frac{-1}{2} & \\frac{-1}{2}\cr 0 & \\frac{3^{0.5}}{2} & \\frac{-3^{0.5}}{2}\cr 1 & 1 & 1 } }
.. math::
\\alpha = \matrix{\\frac{1}{3}}^{0.5}\ e^{\ -j\ \\frac{\pi}{6}\ }
Complex - Three-Phase.
.. math::
y_{n} = \matrix{ x^{T}_{n}\ \gamma\ }\ \scriptsize{[\ \matrix{ 1 & j & 0 }\ ]^{T}}
.. math::
\overline{\scriptsize{Neutral}}\ \qquad\longrightarrow\qquad y_{n} = y_{n}\ \\alpha
Three-Phase - Complex.
.. math::
\overline{\scriptsize{Neutral}}\ \qquad\longrightarrow\qquad x_{n} = \\frac{x_{n}}{\\alpha}
.. math::
y_{n} = \matrix{\ \matrix{ \gamma^{T}\gamma }^{-1}\ \gamma^{T}\ \scriptsize{[\ \matrix{ real(\ x_{n}\ ) & imag(\ x_{n}\ ) & 0 }\ ]^{T}}}^{T}
**Example**
::
from diamondback import ComplexExponentialFilter, ComplexTransform
import numpy
x = ComplexExponentialFilter( 0.0 ).filter( numpy.linspace( -1.0e-4, 1.0e-4, 128 ) + 0.1 )
# Transform an incident signal, forward and inverse.
y = ComplexTransform.transform( x, neutral = True )
z = ComplexTransform.transform( y, neutral = True )
**License**
`BSD-3C. <https://github.com/larryturner/diamondback/blob/master/license>`_
© 2018 - 2022 Larry Turner, Schneider Electric Industries SAS. All rights reserved.
**Author**
Larry Turner, Schneider Electric, Analytics & AI, 2018-01-26.
"""
from typing import List, Union
import math
import numpy
[docs]class ComplexTransform( object ) :
""" Complex transform.
"""
__coefficient = ( 2.0 / 3.0 ) * numpy.array( [ [ 1.0, -0.5, -0.5 ],
[ 0.0, 0.5 * ( 3.0 ** 0.5 ), -0.5 * ( 3.0 ** 0.5 ) ],
[ 1.0, 1.0, 1.0 ] ] )
__gain = ( ( 1.0 / 3.0 ) ** 0.5 ) * numpy.exp( -1j * math.pi / 6.0 )
[docs] @classmethod
def transform( cls, x : Union[ List, numpy.ndarray ], neutral : bool = True ) -> numpy.ndarray :
""" Transforms a real three-phase or complex incident signal into a complex
or three-phase reference signal.
Arguments :
x : Union[ List, numpy.ndarray ] - incident signal.
neutral : bool.
Returns :
y : numpy.ndarray - reference signal.
"""
if ( ( not numpy.isscalar( x ) ) and ( not isinstance( x, numpy.ndarray ) ) ) :
x = numpy.array( list( x ) )
if ( ( len( x.shape ) > 2 ) or ( len( x ) == 0 ) ) :
raise ValueError( f'X = {x}' )
if ( len( x.shape ) < 2 ) :
rows, cols = 1, x.shape[ 0 ]
else :
rows, cols = x.shape
if ( ( rows not in ( 1, 3 ) ) or ( cols <= 0 ) ) :
raise ValueError( f'Rows = {rows} Columns = {cols}' )
if ( rows == 1 ) :
v = x
if ( not neutral ) :
v = x / ComplexTransform.__gain
y = numpy.matmul( numpy.linalg.inv( ComplexTransform.__coefficient ), numpy.array( [ v.real, v.imag, numpy.zeros( cols ) ] ) )
else :
v = numpy.matmul( ComplexTransform.__coefficient, x )
y = v[ 0, : ] + 1j * v[ 1, : ]
if ( not neutral ) :
y *= ComplexTransform.__gain
return y