Stable and Passive Observer-Based V/Hz Control for Induction Motors

This paper proposes an observer-based volts-per-hertz (V/Hz) control method for induction motors. The proposed method consists of a state-feedback control law and a flux observer, both of which are designed to be inherently sensorless. The gains can be selected using simple closed-form expressions, resulting in a locally stable and passive system in the whole feasible operating range. Unstable regions and heuristic tuning of conventional V/Hz control are thus avoided. Compared to sensorless field-oriented control, no speed controller or separate field-weakening method is needed, the full inverter voltage can be utilized, and the sensitivity to parameter errors is reduced.