Implementation of a new speed estimation technique for vector controlled switched reluctance machines

In this paper a discussion on unipolar vector-controlled speed sensorless SRM-drive is underlined. It is well known that SRM-drive requires speed/position information for its efficient control and hence, use of speed/ position sensor is mandatory. As, the limitations posed by speed/position sensors are obvious therefore, there is an urgent need for some speed/position estimation algorithm for having speed sensorless operation. In literature different speed/position estimation techniques are available. Among them MRAS (Model-Reference-AdaptiveSystem) speed-estimators are very simple to implement and free from large LUT's (Lookup-tables). Therefore, this paper concentrates on implementation of a new MRAS based scheme for improving the performance of speed-sensorless vector controlled SRM drive. This scheme uses 'Q0' as the functional candidate for building the MRAS structure. Unlike existing F-MRAS scheme, the proposed sensorless scheme does not require the measured nominal or on-line estimated value of stator resistance. This scheme is totally insensitive to stator resistance of the machine which is verified by performing sensitivity-analysis to stator-resistance variations. Apart from it the given estimation scheme is less sensitive to the inductance related parameter 'Lav' in comparison to 'Z-MRAS' speed estimator which is more sensitive to its respective inductance parameter 'Delta L'. Thus, making the proposed speed estimator better than Z-MRAS speed estimator in this respect. This estimator is also free from drift problems which are associated with pure integrator, as no integration related terms can be seen in both reference and adjustable models of the proposed scheme which is unlike the case of existing F-MRAS scheme which involves integrator in the adjustable model. Also, the proposed MRAS scheme is found to be stable in both motoring and regeneration modes which is concluded by performing the stability-analysis. Thus, making it suitable for aircraft propulsion applications. The sensorless-drive has been simulated in MATLAB/SIMULINK and verified experimentally on the dSPACE-1104 platform.

Automated summary

In this paper, a discussion on unipolar vector-controlled speed sensorless SRM-drive is highlighted. A new MRAS-based scheme is proposed to improve the performance of speed-sensorless vector controlled SRM drive. The proposed scheme does not require the measured value of stator resistance and is insensitive to variations in stator resistance. It is also less sensitive to the inductance related parameter 'Lav' compared to other speed estimators. The proposed scheme is stable and suitable for aircraft propulsion applications.