TORQUE RIPPLE MINIMIZATION CONTROL OF PERMANENT MAGNET SYNCHRONOUS MOTORS FOR EPS APPLICATIONS |
G. H. LEE1, W. CH. CHOI1, S. I. KIM2, S. O. KWON2, J. P. HONG2 |
1Kookmin university 2Hanyang University |
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ABSTRACT |
This paper identifies a control method used to reduce torque ripple of a permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. NVH (Noise Vibration Harshness) is important for safe and convenient driving. Vibration caused by motor torque is a problem in column type EPS systems. Maintaining a very low torque ripple is one solution that allows for smoother steering. Theoretically, it is possible to design and drive the motor without torque ripple. However, in reality, a PMSM system torque ripple is caused by the motor itself (saturation in the iron core and EMF distortion) and the imperfect driver. This paper analyzes torque ripple of a PMSM system, and an advanced PMSM control method for the column typed EPS system is presented. Results of the analysis indicate that the compensation current is needed in order to minimize torque ripple when a PMSM is driven. |
Key Words:
Electric power steering, Magnetic saturation, PMSM, Torque ripple, Deadtime, EMF distortion |
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