Position-sensorless biaxial position control with industrial PM motor drives based on INFORM- and back EMF model

In the presented paper the practical realization of a position sensorless biaxial positioning system based on industrial permanent magnet synchronous motor (PMSM) drives is introduced. At low speed including standstill the INFORM-method is used for sensorless position estimation, at high speed an EMF-based short circuit model is applied. With the help of a proper control structure and a corresponding implementation in the DSP the standard deviation of the estimated rotor position is just about 3-5 degrees (el.) at both models, resulting in a linear position resolution of about 0.05 mm in the presented application. In order to reduce the costs of the drive and to increase its reliability once more the energy consumption at generating mode is implemented without any additional hardware just by a slightly modified control structure. As a result a highly dynamic low-cost sensorless position control with a positioning accuracy of about 3-5° el. is practically realized.