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Hybrid Position Sensorless Control of a RSM in the rated speed range. Francois Barnard Stellenbosch University. Energy Postgraduate Conference 2013. The RSM. Reluctance Synchronous Machine No conductive material (copper/ aluminium ) on rotor
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Hybrid Position Sensorless Control of aRSM in the ratedspeed range Francois Barnard Stellenbosch University Energy Postgraduate Conference 2013
The RSM • Reluctance Synchronous Machine • No conductive material (copper/aluminium) on rotor • Comparable performance under closed-loop controlwith feedback • RSM ASDs have higher operating efficiency compared to induction machine ASDs
Position Sensor • RSM drives require speed/position information • Position sensors unreliable in comparison with complete system • Increase overall cost of systems • Position estimation eliminates the need for a position sensor
Position Estimation • Fundamental model techniques (medium to high speed) • Signal injection saliency based techniques (standstill to low/medium speed) • Viable with modern technology • No single estimation technique sufficiently capable for all operating conditions • Hybrid techniques implement different schemes at different speeds
Active Flux Method • Simulated speed step response
Active Flux Method • Simulated rotor angle tracking (4% error)
Arbitrary Injection • Used with standard field oriented control (FOC), including Space Vector Modulation • No particular injection voltage required, only the presence of a current derivative • Smaller percentage bus voltage than common High Frequency Injection method – higher torque • Adapted to be parameter insensitive – detect motor parameters in the algorithm
Arbitrary Injection • Discrete model derived using Euler approximation of integration • FOC scheme disregards rotor saliency in estimation(using isotropic machine model) • Actual rotor saliency causes estimation error • Estimation error and applied voltage information allows calculation of rotor position
Hybrid Controller • Arbitrary injection estimated angle used to reconstruct active flux vector at low speeds • Deliver sensorless control in entire rated speed range • Control applicable to variable speed generator • Use as part of a wind turbine system Image courtesy of Anusorn P nachol / FreeDigitalPhotos.net