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Embedded Software and Motor Control Libraries for PXR40xx

Embedded Software and Motor Control Libraries for PXR40xx

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The feed-<strong>for</strong>ward voltages u_dq_comp are added to the voltages generated by the current<br />

controllers u_dq, which cover the R-L model. The resulting voltages represent the direct<br />

u q_dec <strong>and</strong> quadrature u q_decq components of the decoupled voltage vector that is to be<br />

applied on the motor terminals (using a pulse width modulator). The back EMF voltage<br />

component is already considered to be compensated by an external function.<br />

The function GMCLIB_DecouplingPMSM_F32 calculates the cross-coupling voltages<br />

u_dq_comp <strong>and</strong> adds these to the input u_dq voltage vector. Because the back EMF<br />

voltage component is considered compensated, this component is equal to zero.<br />

There<strong>for</strong>e, calculations per<strong>for</strong>med by GMCLIB_DecouplingPMSM_F32 are derived<br />

from these two equations:<br />

Equation GMCLIB_DecouplingPMSM_Eq4<br />

where u_dq is the voltage vector calculated by the controllers (with the already<br />

compensated back EMF component), u_dq_comp is the feed-<strong>for</strong>ward compensating<br />

voltage vector described in GMCLIB_DecouplingPMSM_Eq3, <strong>and</strong> u_dq_dec is the<br />

resulting decoupled voltage vector to be applied on the motor terminals. Substituting<br />

GMCLIB_DecouplingPMSM_Eq3 into GMCLIB_DecouplingPMSM_Eq4, <strong>and</strong><br />

normalizing GMCLIB_DecouplingPMSM_Eq4, results in the following set of equations:<br />

Equation GMCLIB_DecouplingPMSM_Eq5<br />

Chapter 4 API References<br />

where subscript f denotes the fractional representation of the respective quantity, <strong>and</strong> U<br />

max, I max, Ω max are the maximal values (scale values) <strong>for</strong> the voltage, current <strong>and</strong> angular<br />

velocity respectively.<br />

Real quantities are converted to the fractional range [-1, 1) using the following equations:<br />

<strong>Embedded</strong> <strong>Software</strong> <strong>and</strong> <strong>Motor</strong> <strong>Control</strong> <strong>Libraries</strong> <strong>for</strong> <strong>PXR40xx</strong>, Rev. 1.0<br />

Freescale Semiconductor, Inc. 463

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