Estimation and Compensation of Load-Dependent Position Error in a Hybrid Stepper Motor
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Estimering och kompensering av lastberoende positionsfel i en elektrisk stegmotor (Swedish)
Hybrid stepper motors are a common type of electric motor used throughout industry thanks to its low-cost, high torque at low speed and open loop positioning capabilities. However, a closed loop control is often required for industrial applications with high precision requirements. The closed loop control can also be used to lower the power consumption of the motor and ensure that stalls are avoided. It is quite common to utilise a large and costly position encoder or resolver to feedback the position signal to the control logic. This thesis has explored the possibility of using a low-cost position sensor based on Hall elements. Additionally, a sensorless estimation algorithm, using only stator winding measurements, has been investigated both as a competitive alternative and as a possible complement to the position sensor. The thesis work summarises and discusses previous research attempts to adequately measure or estimate and control the hybrid stepper motors position and load angle without using a typical encoder or resolver. Qualitative results have been produced through simulations prior to implementation and experimental testing.
The readings from the position sensor is subject to noise, owing to its resolution and construction. The position signal has been successfully filtered, improving its accuracy from 0.56° to 0.25°. The output from the sensorless estimation algorithm is subject to non-linear errors caused by errors in phase voltage measurements and processing of velocity changes. However, the dynamics are reliable at constant speeds and could be used for position control.
Place, publisher, year, edition, pages
2016. , 99 p.
Adaptive Notch Filter, Back-EMF, Electric Motor Position Control, Error Modelling, Field-Oriented Control, Hybrid Stepper Motor, Kalman Filter, Load Angle, Magnetic Rotary Position Sensor, Sensorless Control, Sliding Window Discrete Fourier Transform, Stall Detection and Prediction.
IdentifiersURN: urn:nbn:se:liu:diva-129554ISRN: LiTH-ISY-EX--16/4954--SEOAI: oai:DiVA.org:liu-129554DiVA: diva2:940724
ABB Corporate Research Center in Sweden
Subject / course
2016-06-02, Algoritmen, campus Valla, Linköpings universitet, 581 83 Linköping, 14:00 (English)
Hedberg, Erik, Ph.D. StudentLiu, Bin, Ph.D.
Gunnarsson, Svante, Prof.