Induction motor open- and closed-loop control using Volt-per-Hertz controller

The Volts-per-Hertz controller is designed to accommodate the variable speed commands by using the invertor to apply a voltage of correct magnitude and frequency so as to approximately achieve the commanded speed without the use of speed feedback. The studies are focused first with of open-loop and then with the closed-loop with the application of slew rate. Results show that the slew rate reduces the transient time period which is better for the life of the machine. The steady state error reduces to zero but takes longer time in the closed-loop method.