Sensorless operation of outer-rotor permanent magnet drives with concentrated windings

A drive with permanent magnet synchronous machine (PSM) is presented, which is characterized by a high torque per volume ratio, high efficiency up to wide field weakening range and short-circuit-strength. The construction of the machine contains analytical calculation and numerical simulation of the magnetic behaviour. The used sensorless control method, which works up to three-times rated current down to standstill, is shown. The depicted, Characteristic INFORM curves" (Indirect Flux detection by Online Reactance Measurement) illustrate the sensorless position control capability. Furthermore, the implemented control structure and efficiency and torque measurements of the drive are presented. Calculation, simulation and measurements of the short-circuit-behaviour are also discussed in this paper.