Sensorless Control of Synchronous Reluctance Machines and Permanent Magnet Synchronous Machines for Pump Applications

Sammanfattning: Energy efficiency in electric machines is both environmentally and economically important. Water pumps with an integrated Variable Frequency Drive (VFD) and a Permanent Magnet Synchronous Machine (PMSM) have challenged the status quo of the Induction Machine (IM) for water pumps. The Synchronous Reluctance Machine (SynRM) is also a viable alternative that does not use permanent magnets. This degree project focuses on the control of SynRM, with particular attention on sensorless control methods. Simulation models for a SynRM and a Surface Permanent Magnet Synchronous Machine (SPMSM), together with their control systems, were developed in MATLAB Simulink. Two sensorless control methods were implemented and examined: the Luenberger state observer and the Model Reference Adaptive System (MRAS). The control system was adapted to use sensorless control methods. The investigated sensorless control methods allowed the application of the speed-torque test profile for two method and motor type combinations, without causing instability. The Luenberger observer was stable with the SPMSM and the MRAS with the SynRM. Parameter sensitivity with respect to the variation of inductance and stator resistance values used by the sensorless methods was also tested. The Luenberger observer kept the control system stable with up to a ±5 % variation of inductance. The MRAS kept the control system stable down to −12 %, but only up to +2 % for an overestimation of the inductance. The variation of stator resistance had a limited impact on the stability of both sensorless schemes.