Nowadays, the power steering is a standard device in commercial vehicles. The electric power steering is becoming an alternative to the traditional hydraulic power steering. Right now, the electric drive commonly used in this application is the DC brush motor drive. Today, different electric drives are seen as a future option but the best candidate seems to be the permanent magnet synchronous motor drive. However due to its constructive simplicity, absence of permanent magnets and fault tolerance the switched reluctance motor drive is an alternative that should not be ignored. In this article a switched reluctance motor drive is presented for a rack-type electric power steering for midsize cars with a rack force 10 kN. The drive consists of a switched reluctance motor of four-phase with 8 stator poles and 6 rotor poles fed through an electronic power converter with Power MOSFETs switches, an incremental encoder and digital torque control to minimize torque ripple and to mitigate disturbances that appear when clearing a fault and the drive works with one or two open phases. The drive has been built and tested in the laboratory and experimental results have confirmed its suitability as a drive for power steering.

Peer Reviewed