SRF2ABC:

--------------------------------------------------------------------------
   Transformation from abc to switching reference frame.
   You need to pass the switching function matrix.
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   SRF         (3,1)  Voltage or current in SRF reference frame
   S           (3,3)  Switching function matrix

   -------
   Outputs
   -------
   ABC         (3,1)  Voltage or current in ABC reference frame

--------------------------------------------------------------------------
   Reference:   Nikkhajoei et al "Dynamic Model of a Matrix Converter for
                Controller Design and System Studies", IEEE Transactions
                on Power Delivery, vol. 21, no. 2, April 2006, pp 744-754
--------------------------------------------------------------------------