High-precision Flux Linkage Observation of Induction Motor at Low Switching Frequency

The delay effect caused by the switching device is not considered in traditional methods of induction motor flux observation. However, ignoring the delay effect causes the mathematical model of the induction motor flux observation to be inaccurate. In actual work, this disadvantage will affect the flux observation of the induction motor. It will also influence the anti-load performance of the motor and even lead to system instability. Especially at low switching frequencies, switch delay causes input delay. Input delay will result in configuration poles deviating from their expected position in the closed-loop control, affecting the induction motor performance. In this study, the induction motor time-delay model is established to modify the model and solve the above problem. Spectral decomposition theory is used to establish the induction motor flux observer, which configures the unstable poles of the system. The poles that deviate from their expected position are also reconfigured to the desired position, which improves the motor performance and the observing accuracy of the flux chain. Finally, the process of proving the stability of the spectral decomposition flux observer (SDFO) is provided. The reliability of the SDFO is proven through specific simulations and experiments.