System and method for controlling modulation of an inverter

摘要

A current measurement module is adapted to measure an observed current level for the inverter. A data processor or mode controller accesses a stored representation of first current level versus rotor speed output at which a total harmonic distortion level is less than threshold total harmonic distortion level. The data processor or mode controller enables the inverter to use SVPWM (space vector pulse width modulation) if the observed current level is less than the first current level for the measured or determined rotor speed. Further, the data processor or mode controller enables the inverter to use DPWM (discontinuous pulse width modulation) if the observed current level is greater than or equal to the first current level for the measured or determined rotor speed.

主权项

1. A method for controlling an inverter, the method comprising:
measuring a rotor speed of a motor coupled to the inverter; measuring an observed current level at a fundamental frequency for the inverter; accessing a stored representation of first current level, at the fundamental frequency, versus rotor speed output at which the total harmonic distortion level is less than a threshold total harmonic distortion level, where the total harmonic distortion level can be expressed as a percentage and where the total harmonic distortion level is estimated based on amplitude of one or more harmonic frequencies compared to an amplitude of the fundamental frequency; enabling the inverter to use SVPWM (space vector pulse width modulation) if the observed current level is less the first current level for the measured rotor speed and for the fundamental frequency; and enabling the inverter to use DPWM (discontinuous pulse width modulation) if the observed current level is greater than or equal to the first current level for the measured rotor speed and for the fundamental frequency.