Advanced | SISYM3

SYMMETRIC COMPONENTS – [SISYM3]
Compute the symmetric components of three signals for a given harmonic.
CATEGORY
SI5

DESCRIPTION
This function is used to compute the symmetric components of three signals for a given harmonic. This function computes the module, the phase, and the real and imaginary parts for the symmetric components of a harmonics.
RESULT VARIABLES AND PARAMETERS

Module (m)	Module (or amplitude) for the symmetric components of a harmonic, multiplied by the absolute value of the factor.
Phase (a)	Angle a (or phase) of the symmetric component sequence, between -180 and 180 degrees [°]. Since the module is multiplied by the absolute value of the factor, the phase is modified if the multiplying factor is negative. In this case, 180 degrees are added to the phase.
Phase (a0)	Angle of the symmetric component sequence, found between 0 and 360 degrees [°].
Real (r)	Real part r of the required symmetric component sequence (m * cos(a)).
Imaginary (i)	Imaginary part i of the required symmetric component sequence (m * sin(a)).
Signal_A	First signal to analyze.
Signal_B	Second signal to analyze.
Signal_C:	Third signal to analyze.
Freq	Fundamental frequency of the signal in Hertz [Hz], normally computed with the sifreq function.
Harmonic number	Number of harmonic to compute. 0: DC; 1: Fundamental; 2: 2nd harmonic; n: nth harmonic (max. 30).
Sequence	Sequence of symmetric components to compute. 0: zero sequence 1: positive sequence 2: negative sequence
Begin_time	Time at which the analysis of a signal must start. This time is expressed in milliseconds [ms]. This value must be greater than 0 and lower than the duration of the test. The default value is 0.
End_time	Time at which the analysis of a signal must end. This time is expressed in milliseconds [ms]. The value of this time must be larger than the specified begin_time and smaller than the duration of the test. Use the “HUGE” value to specify the end of the test. The default value is HUGE. The begin_time and end_time specified for the calculation of the harmonics must be the same as those used in the sifreq sequences to compute the fundamental frequency.
Factor:	Multiplying factor for the results generated by the function. The default value of the multiplying factor is 1.0 and has no effect on the results. The factor applies to the moyd, tmax and ttot results.

SYNTAX
[m, a, a0, r, i] = sisym3( a, b, c, 60, 1, 1, 0, HUGE, 1 )
CHARACTERISTICS
Data type support
Double Floating point
EXAMPLE
The following diagram shows the mathematical functions used to compute the symmetric components related to three signals.

m1	module of required harmonic for signal 1
m2	module of required harmonic for signal 2
m3	module of required harmonic for signal 3
a1	angle of required harmonic for signal 1
a2	angle of required harmonic for signal 2
a3	angle of required harmonic for signal 3