Design and Research of a Sliding Mode Observer Based on Line Back-EMF for Brushless DC Motors

Abstract:

This paper designs and implements a sliding mode observer with line-to-line trapezoidal back-EMF for brushless DC (BLDC) motor. Through the detection of three phase voltage and the current, the phase to-phase back-EMF is observed, and then the position signal and the rotor speed are estimated. The corresponding relationship between back-EMF and six rotor positions of the motor is established in this paper. With saturation function instead of sign function, the line current difference is used as the sliding surface. The whole control system employs an inner current PI loop with an outer speed PI loop. Simulation results show that the designed observer can correctly estimate the position information and speed, with strong robustness to changes of system parameters and external disturbances.

• Periodical: Applied Mechanics and Materials (Volume 615)
• Pages: 11-17
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.615.11
• Online since: August 2014
• Authors: Lai Cai Ju*, Zi Qiang Wang, Meng Yu He
• Keywords: Brushless Dc Motor (BLDCM), Line-to-Line Back-EMF, Sensorless Control, Sliding Mode Observer

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