Carel Du Rand

Dr. Carel Du Rand


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 September 2013 in Sensors
Verified
Journal Article
Open access
PDF file
ANAndries C. Niemann
Andries C. Niemann
GSGeorge van Schoor
George van Schoor
CRCarel Du Rand
Carel Du Rand
Active magnetic bearings (AMBs) have become a key technology in various industrial applications. Self-sensing AMBs provide an integrated sensorless solution for position estimation, consolidating the sensing and actuating functions into a single electromagnetic transducer. The approach aims to reduce possible hardware failure points, production costs, and system complexity. Despite these advantages, self-sensing methods must address various technical challenges to maximize the performance thereof. This paper presents the direct current measurement (DCM) approach for self-sensing AMBs, denoting the direct measurement of the current ripple component. In AMB systems, switching power amplifiers (PAs) modulate the rotor position information onto the current waveform. Demodulation self-sensing techniques then use bandpass and lowpass filters to estimate the rotor position from the voltage and current signals. However, the additional phase-shift introduced by these filters results in lower stability margins. The DCM approach utilizes a novel PA switching method that directly measures the current ripple to obtain duty-cycle invariant position estimates. Demodulation filters are largely excluded to minimize additional phase-shift in the position estimates. Basic functionality and performance of the proposed self-sensing approach are demonstrated via a transient simulation model as well as a high current (10 A) experimental system. A digital implementation of amplitude modulation self-sensing serves as a comparative estimator.

1 December 2011 in Sensors and Actuators A: Physical
Verified
Journal Article
Closed access
ERE.O. Ranft
E.O. Ranft
GSGeorge van Schoor
George van Schoor
CRCarel Du Rand
Carel Du Rand

5 November 2012 in Sensors and Actuators A: Physical
Verified
Journal Article
Closed access
GSGeorge van Schoor
George van Schoor
ANA.C. Niemann
A.C. Niemann
CRCarel Du Rand
Carel Du Rand


1 December 2011 in Sensors and Actuators A: Physical
Verified
Journal Article
Closed access
ERE.O. Ranft
E.O. Ranft
GSGeorge van Schoor
George van Schoor
CRCarel Du Rand
Carel Du Rand