Standstill Sensorless Self-Commissioning Strategy of Synchronous Machines Including Initial Positioning and Torque Canceling Techniques

Abstract

This article proposes a standstill sensorless self-commissioning strategy for synchronous machines, including the initial positioning and torque canceling techniques. The proposed identification consists of the self-axis test to identify self-saturation and the cross-saturation test to identify cross-saturation. An inverter feeds the machine during the process. The induced current and the flux data can be gathered from multi-points within the current constraints to identify the flux saturation characteristics. The induced current generates the torque, including the magnetic and reluctance torque. The generated torque moves the rotor, and the data would be distorted since the data gathering assumes the rotor stands still. However, the rotor position can be maintained if each torque is canceled. The proposed method considers not only the magnetic torque but also the reluctance torque, which is not considered in the conventional method. Initial positioning with zero speed is achieved with the proposed techniques. So, more accurate data can be obtained, and the self-commissioning time is significantly reduced since the additional alignment process can be removed. Experiments were performed on a 1.5 kW SynRM and an 11 kW IPMSM, and the results proved the effectiveness of the proposed method.