Dr Paul Lefley

Academic and chartered electronics engineer

Paul Lefley

Personal details

  • In-depth practical electronics expertise (including aerospace electronics, control systems, and power electronics)
  • Director for the MSc in Advanced Electrical and Electronic Engineering
  • Formula Student Coordinator
  • IET Liaison Officer

BSc (Eng), PhD, CEng, MIET, MIEEE, FHEA
T: +44 (0)116 252 2526
F: +44 (0)116 252 2619
E: pwl3@le.ac.uk

Location: Room 1002, Engineering Tower

Electronics expertise (including industrial power and aerospace electronics)

Publications

Analysis of the stator topology impact on cogging torque for surface permanent magnet motor, Lidija Petkovska , Paul Lefley, Goga Cvetkovski, COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, Vol. 34 Iss: 2, pp.456 – 474, 2015

Optimal design of single phase permanent magnet brushless DC motor using particle swarm optimisation,Goga Cvetkovski , Lidija Petkovska , Paul Lefley, COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, Vol. 33 Iss: 6, pp.1863 – 1876. Published 13/11/14

Evaluation of Two Global Optimization Techniques for Total Loss Reduction of a Distribution Transformer, Digalovski M, Lefley P, The 5th International Symposium on Applied Electromagnetics – SAEM'2014, Skopje, Macedonia, June 8-11, 2014

Implementation of Skewing and Dummy Slots in Stator Teeth for Cogging Torque Reduction of PM Synchronous Motor, Cvetkovski G, Petkovska L, Lefley P, The 5th International Symposium on Applied Electromagnetics – SAEM'2014, Skopje, Macedonia, June 8-11, 2014

Finite Element Modelling of the Double Stator Cup-Rotor Machine, Diryak E, Lefley P, The 5th International Symposium on Applied Electromagnetics – SAEM'2014, Skopje, Macedonia, June 8-11, 2014

• Multi-Objective GA Minimisation of Permanent Magnets’ Weight of Axial Field Motor for EV Drive, Cvetkovski G, Gair S, Lefley P, iEEE International Magnetics Conference - INTERMAG 2014, Dresden, Germany, May 2014.

• Iron Loss Optimisation of a Distribution Transformer, Digalovski M, Lefley P, Petkovska L, The 9th IET International Conference on Computations in Electromagnetics - CEM 2014, London, March 2014.

• Analysis of a New Design of Single Phase Permanent Magnet Brushless DC Motor for Low Cost Applications, Lefley P, Petkovska L,  Ahmed S, and Cvetkovski G, The 9th IET International Conference on Computations in Electromagnetics - CEM 2014, London, March 2014

• Evaluation Studies of Combined Wavelet and Neural Network Applications in High Voltage Transmission Line Protection, JWAD D, Lefley P, The 12th International Conference on Developments in Power System Protection – DPSP 2014, Copenhagen, Denmark, 31 March – 3 April 2014.

• ISTET2013 Particle Swarm Design Optimisation of Single Phase Permanent Magnet Brushless DC Motor, Cvetkovski G, Petkovska L, Lefley P, Ahmed S, International Symposium on Theoretical Electrical Engineering – ISTET2013, Pilsen, Czech Republic, June 24 – 26, 2013.

• In-Depth Cogging Torque Analysis of a Single Phase PMBLDC Motor, P. Lefley, L. Petkovska, G. Cvetkovski, ISEF 2013 - XVI International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, Ohrid, Macedonia, September 12-14, 2013.

• Design Optimization of a Double Stator Cup-Rotor Machine, E. Diryak, P. Lefley, L. Petkovska, and G. Cvetkovski, World Academy of Science, Engineering and Technology 71 PP 1569-1575, Paris, November 2012.

• Optimal Design of a Novel Single Phase PM BLDC Motor Using Genetic Algorithm, Lefley P, Ahmed S, EPE-PEMC 2012, Novi-Sad, September 2012.

• Cogging Torque Minimization in the Double Stator Cup Rotor Machine, Diryak E, Lefley P, 4th Symposium on Applied Electromagnetics SAEM'12, 3rd to 6th June 2012, Sopron Hungary.

• High Voltage, High Frequency Transformer Design, Lefley P, Devine P. Transformers Analysis Design and Measurement, CRC Press, Monograph Ch 21, ISBN 9781466508248.

• Synthesis and Analysis of a High-performance Low-cost Permanent Magnet Brushless DC Motor, Lefley P,  International journal for Computation and Mathematics in Electrical and Electronic Engineering (COMPEL).

• Fault Detection of a Series Compensated Line during the Damping Process of Inter-area Mode of Oscillation, Lami F, Lefley P. IET DPSP 2012 - Protecting the Smart Grid. The 11th International Conference on Developments in Power System Protection. 23-26 April 2012.

 

Research

Research Interests

My research interests are principally in four areas: practical electronic systems, novel electrical machines, drives and control, and the application of power electronics and pulsed power to new areas, for example, ultra-rapid battery recharging for various kinds of batteries and electric vehicles. I have an international reputation on all of this work, and much of it has been commercialized through two spin-out companies. I would like to encourage interested parties to make contact to find out how they can become involved with his research.

Electrical Machines and Drives:
Recent work in the field of electrical machines has lead to the development of a new type of brushless electric motor that is energy efficient, electronically controlled and has a low manufacturing cost, with the intention to make OEM manufacturers aware of an alternative to the world’s reliance on inefficient single phase induction motors. These energy efficient motors are based on new patented designs and are essentially permanent magnet based brushless DC motors with very low electronic component count. The new designs have been developed for low torque ripple and quiet operation. The new motors are attracting growing commercial interest worldwide. See also the link to the Centre for Advanced Electrical Machines and Drives at Leicester.

I have considerable experience in developing various types of novel electric motors, in particular for electric and hybrid vehicles. However, recently I have also developed new bespoke motor/generator technologies for aerospace applications where high power densities at very high speeds are essential. Such machines are designed to be directly coupled to gas-turbines for power generation and APU applications. The machine performs initially as a high speed starter and then as a generator after the gas-turbine has fired up. This is a new field and is of considerable interest not only in aerospace but in military applications as well. I have also developed in conjunction with colleagues from the Electrical and Electronic Power Engineering Group a complete fuel cell based electric vehicle drive system using a Nexa fuel cell, ultra-capacitors for energy storage, and an energy efficient permanent magnet brushless DC motor.

Dr Paul Lefley - nexa fuel cell

Fig 1: Nexa fuel cell; part of the electric vehicle traction drive system developed in the Electrical and Electronic Power Engineering Group

Electronics expertise (including industrial power and aerospace electronics)

Current Major Research Projects:

Power Electronics and Pulsed Power
I have considerable experience in the development of power electronic based systems including recently, the application of pulsed power both at very high currents and high voltages. The work on ultra-rapid battery recharging stemmed from fundamental work on how a rechargeable battery may accept charge at a high rate without causing deleterious effects to the battery such as overheating, gassing, active material shedding, etc. A new recharging scheme has been devised to inject charge into the battery at a very high rate.

The work on very high current power electronics (up to 2,500 amps) is applicable to all large scale energy storage media, and interested parties are encouraged to contact Dr. Lefley. Much of the ultra-rapid battery recharging development is currently seeing commercial interest. The work on electrostatic precipitation was an application of modern high frequency switched mode power electronics to replace the traditional low frequency transformer/rectifier set, but also, to improve the dust collection efficiency in the precipitator by applying a controllable pulsed waveform from the new power supply. This system was implemented in a pilot project at Didcot B power station in Oxfordshire, UK.

Electrical Machines

I continue to develop low cost, energy efficient electric motors based on the single phase BLDC motor design, as well as high power density machines for aerospace applications. The most recent project is the development of an electromagnetic torque amplifier (or converter). This is a very novel idea intended for hybrid electric vehicles. It combines aspects from both a series hybrid and a parallel hybrid drive trains, with the intention to reduce the weight and cost of existing hybrid vehicle power plant and transmission systems.

Dr Paul Lefley - energy efficient electric motor

Fig 2: A CAD model of a new energy efficient electric motor

Total income to date (research, KTPs, business development, consultancies):  £ 867k.

 

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