Embedded Software and Motor Control Libraries for PXR40xx

• actual amplitude of the DC bus voltage U DC_BUS_ACTUAL=90[V]
• voltage to be applied to the PWM modulator to generate U reg=50[V] on the inverter
phase output:
Equation GMCLIB_ElimDcBusRip_Eq2
The imperfections of the DC bus voltage are compensated for by the modification of
amplitudes of the direct- α and the quadrature- β components of the stator reference
voltage vector. The following formulas are used:
• for the α-component:
• for the β-component:
Equation GMCLIB_ElimDcBusRip_Eq3
Equation GMCLIB_ElimDcBusRip_Eq4
Chapter 4 API References
where fltModIndex is the inverse modulation index, fltArgDcBusMsr 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 fltModIndex and fltArgDcBusMsr are supplied to the function within the parameters
structure through its members. The u α, u β correspond respectively to the fltArg1 and
fltArg2 members of the input structure pIn, and the u α* and u β* respectively to the
fltArg1 and fltArg2 members of the output structure pOut.
It should be noted that although the modulation index (see the parameters structure
pParam, the fltModIndex 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.
Embedded Software and Motor Control Libraries for PXR40xx, Rev. 1.0
Freescale Semiconductor, Inc. 485