Speed-sensorless state feedback control of induction machines with LC filter
It addresses the challenge of sensorless control for induction machines with LC filters, offering a practical solution with easy tuning for industrial applications.
The paper proposes a speed-sensorless state feedback controller for induction machines with LC filter, using a speed-adaptive observer and gain-scheduled LQR. Experimental validation shows good performance under various load and speed conditions, including zero-speed crossings.
A speed-sensorless state feedback controller for induction machines (IMs) with LC filter is proposed. The estimation of speed and remaining states is based on a speed-adaptive observer, requiring only the measurement of the filter input currents. The motor currents are controlled by a state-feedback controller with proportional and integral control action to achieve fast and asymptotic set point tracking. Observer \emph{and} controller gains are calculated offline using linear quadratic regulator (LQR) theory and updated online (gain-scheduling), in order to guarantee stability and improve control performance in the whole operation range. The proposed control scheme is validated by simulation and experimental results including several zero-crossings of the mechanical speed. It is shown that the overall control system performs well under various load- and speed conditions; while its tuning remains easy making it attractive also for industrial application.