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This paper presents a theoretical analysis of a Maximum Torque Per Ampere control strategy based on the Extremum Seeking Control working principle, which provides useful insights for the definition of a systematic and quantitative design procedure. The focus is on the convergence properties to the optimal operating point, and a method for evaluating an upper bound of the convergence time is proposed. The analysis is supported by several experimental tests performed on an Interior Permanent Magnet Synchronous Motor

(2017) Energy-efficient autonomous solar water-pumping system for permanent-magnet synchronous motors. IEEE Transactions on Industrial Electronics, 64 (1). pp. 43-51. ISSN 1557-9948Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/40003/1/Energy-efficient%20autonomous%20solar%20water-pumping%20system%20for%20permanent-magnet%20synchronous%20motors.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1 Energy-efficient autonomous solar water-pumping system for permanent magnet synchronous motors Riccardo Antonello, Member, IEEE, Matteo Carraro, Alessandro Costabeber, Member, IEEE, Fabio Tinazzi, and Mauro Zigliotto, Member, IEEEAbstract-This paper presents a novel stand-alone solarpowered water pumping system, especially suited for usage in rural or remote areas. The system is primarily designed to reduce both cost and complexity, while simultaneously guaranteeing optimal utilisation of the photovoltaic generator. The use of standard hardware and control architectures ensures ease of installation, service and maintenance. The proposed solution consists of a water pump driven by a permanent magnet synchronous motor (PMSM), controlled by a conventional field oriented control scheme. The photovoltaic array is directly connected to the DC bus of the inverter, with no intermediate power conversion stages. A perturbation based extremum-seeking controller adjusts the motor speed reference to attain the maximum power point operation of the photovoltaic array. Both simulations and experimental results on a full-scale prototype support the effectiveness of the proposed system. Index Terms-PMSM drives, MPPT tracking, PV water pumping, extremum seeking control NOMENCLATURE Variables names convention (letter / subscript):• uppercase / uppercase: large-signal DC quantity.• lowercase / lowercase: small-signal quantity.• uppercase / lowercase: amplitude of a small-signal sinusoidal perturbation.• lowercase / uppercase: total quantities (i.e. small-signal perturbation superimposed on large-signal DC quantity) Symbols used: p P , u P PV array output power and voltage. p C , p I power stored in DC bus capacitor, power absorbed by the inverter. p R , p M Joule losses and delivered mechanical power. u D,Q , i D,Q PMSM voltages and currents in the dq frame.

As a step towards the self-commissioning of the next generation of AC drives, the work deals with an automatic procedure for the identification of the inverse-Gamma equivalent circuit of inverter-fed induction motors (IM) at standstill. The algorithm, cut out for the modern microprocessors, combines different test signals with the aim of extracting and mapping the magnetic model non--linearity. As a key feature, the procedure uses the existing inverter as a precise voltage probe, to get the complete parameter set usually required by the advanced control of AC drives. The theoretical investigations are supported by experimental results, and reported in the paper. A distinguished characteristic of the proposed method among the other existing solutions is the accuracy of the results, confirmed by the comparison with finite-element analysis tools, tailored to the laboratory IM prototypes