Self-sensing control of the externally-excited synchronous machine for electric vehicle traction application

Authors: Mohamad Koteich, Amir Messali, Simon Daurelle

Conference: 2017 IEEE International Symposium on Sensorless Control for Electrical Drives (SLED), Catania, Italy.

DOI: 10.1109/SLED.2017.8078436

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Abstract: This paper studies the possibility of removing the position sensor from electric vehicles (EVs) powertrains that employ the externally-excited synchronous machine (EESM) for traction. Three position estimation approaches are studied: back-electromotive-force integration, state-observer and high-frequency voltage injection approaches. Theoretical background is presented, a comparative performance analysis is performed, and experimental results on a 65-kW EESM drive test bench are shown. Some requirements for EV powertrains are emphasized.

Flux estimation algorithms for electric drives: a comparative study

Author: Mohamad Koteich

Conference: REDEC – International Conference on Renewable Energies for Developing countries, July 2016, Lebanon.

DOI: 10.1109/REDEC.2016.7577558

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Abstract: This paper reviews the stator flux estimation algorithms applied to the alternating current motor drives. The socalled voltage model estimation, which consists of integrating the back-electromotive force signal, is addressed. However, in practice, the pure integration is prone to drift problems due to noises, measurement error, stator resistance uncertainty and unknown initial conditions. This limitation becomes more restrictive at low speed operation. Several solutions, reported in the literature, are reviewed and compared. Emphasis is placed on the low-pass filter based algorithms that show good performance in steady-state as well as in transient operating conditions.

Energy Equalization Module for Modular Multilevel Converters in Variable Speed Motor Drives

Authors: Mohammad Sleiman, Mohamad Koteich, Handy Fortin Blanchette, Hadi Kanaan, Kamal Al-Haddad

Conference: REDEC – International Conference on Renewable Energies for Developing countries, July 2016, Lebanon.

DOI: 10.1109/REDEC.2016.7577559

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Abstract: Modular Multilevel Converters (MMC) processing phase quantities at low frequency are vulnerable to high cell voltage ripples. MMC upper and lower arms processes pulsating power at fundamental and second harmonic phase components. As a consequence, arms are expected to buffer the energy difference exchanged between DC-link and each AC-phase. This buffered energy is translated into increased cell voltage ripple when operating at low phase frequency. Several remedies have been presented in literature, which can be classified under software and hardware methods. To address this short-come we introduced a plug-in hardware alternative that permit energy exchange between cells from upper and lower arms thus remarkably reducing capacitor voltage ripples caused by out of phase energy variations. The proposed method can improve MMC performance over the full operation region and is mainly attractive to low frequency operation such as in variable-speed motor drives where higher-than-nominal torques might be required for a wide speed range. Performed simulations over a synchronous machine using maximum torque per current control technique, conforms well with the analytical findings and shows the effectiveness of the proposed method.

A unified model for low-cost high-performance AC drives: the Equivalent Flux concept

Authors: Mohamad Koteich, Gilles Duc, Abdelmalek Maloum, Guillaume Sandou

Conference: The Third International Conference on Electrical, Electronics, Computer Engineering and their Applications (EECEA2016), Apr 2016, Beirut, Lebanon.

DOI: 10.1109/EECEA.2016.7470768

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Abstract: This paper presents a unified modeling approach of alternating current (AC) machines for low-cost high-performance drives. The Equivalent Flux concept is introduced. Using this concept , all AC machines can be seen as a non-salient synchronous machine with modified (equivalent) rotor flux. Therefore, complex salient-rotor machines models are simplified, and unified shaft-sensorless AC drives can be sought. For this purpose, a unified observer-based structure for rotor-flux position and speed estimation is proposed. The equivalent flux concept generalizes the existing concepts, such as the extended back-electromotive force, the fictitious flux and the active flux.

Local Weak Observability Conditions of Sensorless AC Drives

Authors: Mohamad Koteich, Abdelmalek Maloum, Gilles Duc, Guillaume Sandou

Conference: 17th Conference on Power Electronics and Applications-EPE’15-ECCE Europe, Geneva, Switzerland, 8-10 September 2015

DOI: 10.1109/EPE.2015.7309238

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Abstract: Alternating current (AC) electrical drive control without mechanical sensors is an active research topic. This paper studies the observability of both induction machine and synchronous machine sensorless drives. Observer-based sensorless techniques are known for their deteriorated performance in some operating conditions. An observability analysis of the machines helps understanding (and improving) the observer’s behavior in the aforementioned conditions.

Permanent magnet synchronous drives observability analysis for motion-sensorless control

Authors: Mohamad Koteich, Abdelmalek Maloum, Gilles Duc, Guillaume Sandou

Conference: 6th IEEE International Symposium on Sensorless Control for Electrical Drives – SLED, Sydney, NSW, Australia, 7-8 June 2015.

DOI: 10.1109/SLED.2015.7339264

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Abstract: Motion-sensorless control techniques of electrical drives are attracting more attention in different industries. The local observability of sensorless permanent magnet synchronous drives is studied in this paper. A special interest is given to the standstill operation condition, where sensorless drives suffer of poor performance. Both, salient and non-salient machines are considered. The results are illustrated using numerical simulations.

Observability analysis of sensorless synchronous machine drives

Authors: Mohamad Koteich, Abdelmalek Maloum, Gilles Duc, Guillaume Sandou

Conference: 2015 European Control Conference (ECC), Linz, Austria, 15-17 July 2015, pages 3560-3565.

DOI: 10.1109/ECC.2015.7331085

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Abstract: This paper studies the local observability of synchronous machines using a unified approach. Recently, motion sensorless control of electrical drives has gained high interest. The main challenge for such a technology is the poor performance in some operation conditions. One interesting theory that helps understanding the origin of this problem is the observability analysis of nonlinear systems. In this paper, the observability of the wound-rotor synchronous machine is studied. The results are extended to other synchronous machines, adopting a unified analysis. Furthermore, a high-frequency injection-based technique is proposed to enhance the sensorless operation of the wound-rotor synchronous machine at standstill.