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Durham Energy Institute



New book on Synchronous Reluctance Motor Technology

(20 September 2017)

Magnetic laminations for the rotor of an experimental synchronous reluctance motor

Dr Christopher Donaghy-Spargo has recently agreed to produce a manuscript for a forthcoming book on high energy efficiency electric motors for the Institution of Engineering and Technology (IET). Dr Donaghy-Spargo is Assistant Professor of Electrical Engineering, Deputy Research Challenge Director for Future Energy Systems in the Department of Engineering and DEI Early Career Fellow

The hardcover is to be entitled ‘Synchronous Reluctance Motor Technology: An Introduction’, its aim is to provide academic researchers and industrial engineers with a comprehensive overview of this type of electric motor and compare it with existing technology. It will cover the fundamental theory, design operation and recent advances in this energy efficient technology.

The Synchronous Reluctance motor is slowly becoming the replacement technology of choice for the traditional Induction Motor in variable speed industrial motor-drive applications where high energy efficiency is required. Despite the fact that the Synchronous Reluctance motor was invented in the 1920’s, it has not enjoyed large scale industrial deployment due to the widespread use of the Induction Motor (an older but sufficiently robust and efficient motor with good self-starting and controllability for almost all practical industrial applications such as pumps, mills and blowers) and the conservative stance of industry in general – if it isn’t broken, don’t fix it

Government figures indicate that almost 50% of all the electrical power generated in the UK drives electric motors and around 60-70% of these are three phase induction motors, as found in every industrial facility in the country. Recent UK and EU legislation now requires that industrial motors meet higher efficiency standards to effect a reduction in industrial energy demand and carbon emissions. From the electric motor design perspective, it is difficult to improve the induction motor to meet these standards with the trade-offs of size, weight, cost and manufacturing complexity. The adoption of Permanent Magnet Synchronous Motors would meet the performance requirements, however, to produce these machines on the annual volume of new machines required, would be very demanding on global Rare Earth reserves and rather expensive CAPEX. As such, the Synchronous Reluctance motor, which contains no permanent magnets or rotor windings, using only the attractive force of an electromagnet picking up and iron nail, to produce a torque on the rotor shaft, has been recently commercialised by a number of large electrical companies. This motor technology offers low manufacturing complexity, good performance characteristics and higher energy efficiency – typically 3-4% more efficient than a comparative Induction Motor. Over the lifetime of an industrial motor (many years) on 24/7 operation represents a large potential saving in energy demand and the consequential reduction in carbon emissions. Recent studies have suggested that by increasing the efficiency of the global platform of industrial motors by this 3%, over 100GW of electrical power generation could be decommissioned due to demand reduction. The Synchronous Reluctance motor certainly has a role to play.

Dr Donaghy-Spargo has been engaged in research into the Synchronous Reluctance Motor since 2011. In 2016 he published a paper “Synchronous Reluctance Motor Technology: Industrial Opportunities, Challenges and Future Direction”, outlining the energy efficient benefits of this technology in IET Engineering & Technology Reference, DOI: 10.1049/etr.2015.0044. He continues to research advanced topologies of this type of motor with the aim of further increasing the energy efficiency for industrial applications.

The manuscript is due to be completed December 2018 and will be published for sale via SciTech Publishing, the publisher of the Institution of Engineering and Technology, in Q1 2019.

The completed volume will be the first book dedicated to this specific electric motor technology since 1996.