A Hybrid Active Flux Observer Based Encoderless Control Method for AC Motor Drives

This paper addresses a novel hybrid active flux observer based encoderless control scheme for AC motors. An Extended State Observer (ESO) is used to combine voltage model (VM) and current model (CM), and stabilizes the critically stable VM. Moreover, an adaptive law is designed to identify and compensate the voltage errors caused by inverter nonlinearities. The low-speed operation performance is improved via the proposed control scheme. Experimental results conducted on an asynchronous motor verify the effectiveness of the proposal.