AC Kinetics purchased a drive claimed to be the “World’s Best Drive” for the tests below, and configured this drive in its standard and energy-saving modes. This drive is labeled Drive 1 in the plots to follow. The energy savings and performance improvements measured from an implementation of the AC Kinetics drive control algorithms are compared with this drive and another leading commercial drive in industry today. For a brief description of each of the test protocols, please see the Results section.
The error and energy consumption totals are given below.
Note: Drive 1 deviated from the reference significantly when the load disturbance was applied. This large tracking error meant that Drive 1 was controlling the motor to operate at a significantly lower speed for much of the data collection window, leading to a small yet deceiving input power number. Had the drive better maintained tracking of the speed reference, it would have consumed more energy.
Steady State Efficiency
The plot below shows how motor efficiency changes under the control of each drive at five different speeds as the load was swept from 20% of rated to 100% rated torque. The first crest shows motor efficiency under increasing load at 350 RPM, the second crest shows motor efficiency under increasing load at 700 RPM, etc.
For the industrial cycle tests, each drive was commanded to make the motor follow a trapezoidal velocity reference that accelerated a large inertia between zero and rated speed. A constant load was also applied to the motor shaft by a separate brushless motor setup. Torque was measured on the load motor side of the inertia, so all torque output by the induction motor to overcome bearing friction and accelerate the inertia is not captured by this measurement.