Single-Sensor-Based Three-Phase Permanent-Magnet Synchronous Motor Drive System With Luenberger Observers for Motor Line Current Reconstruction

This paper presents an algorithm that enables single-sensor operation of vector-controlled three-phase permanent-magnet-synchronous-motor voltage source inverter (VSI)-based drive systems. The closed-loop operation is performed through measuring only the VSI dc-link current. The measured VSI dc-link current is fed to a space-vector-based lookup table, which reconstructs the motor line currents. Three Luenberger-style observers are used to filter out the reconstructed motor line currents and estimate the rotor position and speed. The effect of observer bandwidth on the accuracy of the motor´s estimated parameters is also investigated. The drive system´s physical dynamic stiffness is used as a key metric to compare the drive system performance in single-sensor mode and fully sensored mode, in order to find the lowest steady-state speed limit for the single-sensor drive system operation.