Patent ID: 6477067
Filing Date: 2002-11-05
Classification: H02M

Abstract:
An apparatus for reducing distortion at the output terminals of an inverter drive system, wherein the system includes an N phase inverter and an inverter controller, the inverter including a plurality of switches that link positive and negative DC buses to N output terminals, a separate terminal for each of the inverter phases, the controller receiving N modulating signals and a carrier signal and comparing the modulating signals and the carrier signals to generate firing pulses to control the switches, the apparatus comprising, for each of the N phases:a polarity discriminator for determining the polarity of the current passing through the phase output terminal; a device dynamics compensator including upper and lower compensation values where the upper compensation value is different than the lower compensation value, the compensator linked to and receiving the polarity signal from the discriminator and, when the polarity is positive, providing the upper compensation value as an compensation signal and, when the polarity is negative, providing the lower compensation value as the compensation signal; and a combiner for receiving the modulating signal and the compensation signal and mathematically combining the modulating and compensation signals.