Adaptive V/f-based control for induction machines in distributed electric propulsion systems

A novel adaptive control function is presented as an improvement to the classic volts per hertz (V/f) technique where high torque oscillations occur during rapid changes of the rotating speed. The proposed adaptive feature of an improved controller limits torque oscillations by injecting a pulse and imposing the pre- determined bands on a voltage reference waveform whenever the scheduled change in speed occurs. This adaptive function has been integrated with the closed-loop V/f control scheme, subsequently modelled and evaluated numerically using transient simulation studies, as well as experimentally using an induction machine drive test rig. The results have shown that the proposed adaptive element provides an improved dynamic performance for using the V/f method, which is required in compact distributed drive systems with single voltage source inverter (VSI) controlling multiple interconnected motors