Patent ID: 9595907
Date: 2017-03-14
CPC Classifications: H02P

Claim:
1. A method for controlling an inverter, the method comprising: measuring or determining, by an interface, a fundamental frequency output of at least one phase output of the inverter; measuring, by a current measurement module, an observed current level for the inverter; accessing, by a data processor, a stored representation of first current level versus fundamental frequency output at which a total harmonic distortion level, is less than threshold total harmonic distortion level; enabling, by a mode controller, 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 fundamental frequency; and enabling, by the mode controller, 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 fundamental frequency, wherein the enabling of the inverter to use DPWM further considers a first countervailing factor of hysteresis to oppose or inhibit the use of DPWM for an observed sampling period if the observed current level is greater than or equal to the first current level by less than a hysteresis amount for a sampling period and if the inverter is currently operating in the SPWM mode for an earlier sampling period substantially immediately prior to the observed sampling period.