Embedded Software and Motor Control Libraries for PXR40xx

Function GMCLIB_ElimDcBusRip_F32
Equation GMCLIB_ElimDcBusRip_Eq4
where: f32ModIndex is the inverse modulation index, f32ArgDcBusMsr is the measured
DC bus voltage, the u α and u β are the input voltages, and the u α* and u β* are the
output duty-cycle ratios.
The f32ModIndex and f32ArgDcBusMsr are supplied to the function within the
parameters structure through its members. The u α, u β correspond respectively to the
f32Arg1 and f32Arg2 members of the input structure, and the u α* and u β* respectively
to the f32Arg1 and f32Arg2 members of the output structure.
It should be noted that although the modulation index (see the parameters structure, the
f32ModIndex member) is assumed to be equal to or greater than zero, the possible values
are restricted to those values resulting from the use of Space Vector Modulation
techniques.
In order to correctly handle the discontinuity at f32ArgDcBusMsr approaching 0, and for
efficiency reasons, the function will assign 0 to the output duty cycle ratios if the
f32ArgDcBusMsr is below the threshold of 2 -15 . In other words, the 16 least significant
bits of the f32DcBusMsr are ignored. Also, the computed output of the and u β*
components may have an inaccuracy in the 16 least significant bits.
Note
Both the inverse modulation index pIn->f32ModIndex and the
measured DC bus voltage pIn->f32DcBusMsr must be equal to
or greater than 0, otherwise the results are undefined.
4.103.5 Re-entrancy
The function is re-entrant.
4.103.6 Code Example
#include "gmclib.h"
#define U_MAX (36.0) // voltage scale
SWLIBS_2Syst_F32 f32AB;
Embedded Software and Motor Control Libraries for PXR40xx, Rev. 1.0
478 Freescale Semiconductor, Inc.