Optimal State Control of Induction Machine with Improved Stator Flux Estimation

The concept of stator flux orientation control of induction motor (IM) based on the optimal regulator theory has been introduced in the literature. In this paper, the idea is expanded to improve the performance at low speeds by proposing programmable low-pass filter (LPF) for flux vector synthesis. The developed control structure provides high-quality signal for the stator frequency. This signal is utilized here to determine the filter coefficients as well as the vector rotator. Compared with other programmable LPF implementations, the presented one is likely to provide better results since it is independent of the machine equations and doesn´t impose additional dynamic delay. Simulation and experimental studies on 1-kW three-phase induction motor are provided to validate the method.