C2000 Space Vector Generator

Duty ratios for stator reference voltage

Library

Embedded Coder^® Support Package for Texas Instruments™ C2000™ Processors/ Optimization/ C28x DMC

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Description

This block calculates duty ratios that generate a given stator reference voltage using space vector PWM technique. Space vector pulse width modulation is a switching sequence of the upper three power devices of a three-phase voltage source inverter and is used in applications such as AC induction and permanent magnet synchronous motor drives. The switching scheme results in three pseudosinusoidal currents in the stator phases. This technique approximates a given stator reference voltage vector by combining the switching pattern corresponding to the basic space vectors.

The inputs to this block are

• Alpha component — the reference stator voltage vector on the direct axis stationary reference frame (Ua)

• Beta component — the reference stator voltage vector on the direct axis quadrature reference frame (Ub)

The alpha and beta components are transformed via the inverse Clarke equation and projected into reference phase voltages. These voltages are represented in the outputs as the duty ratios of the PWM1 (Ta), PWM3 (Tb), and PWM5 (Tc).

Note

The implementation of this block does not call the corresponding Texas Instruments library function during code generation. The TI function uses a global Q setting and the MathWorks^® code used by this block dynamically adjusts the Q format based on the block input. See Using the IQmath Library for more information.

References

For detailed information on the DMC library, see C/F 28xx Digital Motor Control Library, Literature Number SPRC080, available at the Texas Instruments Web site.