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Christopher Lee

Towards Advanced Electric Motors

Assistant Professor, Nanyang Technological University

NRF Fellow Assistant Professor Christopher Lee from Nanyang Technological University's School of Electrical & Electronic Engineering is reinventing electric motors for next-generation vehicles and aircrafts.


An experimental setup for motor testing. Photo: Dr Christopher Lee

Born and raised in the seaside town of Aberdeen, Hong Kong, Assistant Professor Christopher Lee did not grow up wanting to be a scientist.

His childhood ambition was to be a high school teacher, which offered a rewarding and stable career. “I planned to study hard and get a good job to change my life,” he says. For a while, life seemed to be going according to plan – he graduated from university at the top of his class and became a high school teacher, a career which he thought he would stay in for good.

But that changed in 2011, when tsunami waves hit Fukushima and left many reeling from the nuclear disaster. Watching the scenes play out on the television, Dr Lee realised that his science degree could be put to a better use – in the development and application of other, safer sources of sustainable energy. In March that year, Dr Lee quit his job at the high school and returned to academia at his alma mater, The University of Hong Kong, with this newfound ambition. His bachelor’s degree in electrical engineering meant a natural pivot to focus on electric vehicles, which Dr Lee believes is a “very promising solution…to ever-increasing concerns about the energy crisis and environmental pollution”.

“I would not say that electricity can replace fossil fuel energy, but I am very confident that electrical energy will step up gradually in the next few decades,” he adds. “I can foresee that both fossil fuel and electrical energy will be used in parallel in our future society.”

Reinventing a century-old technology

Invented over a century ago, electric motors are today used in almost every modern-day appliance, including refrigerators and computer hard drives. And they are promising – electric cars, for instance, do away with the need for gasoline and diesel by relying on these motors to convert electrical energy into mechanical energy, propelling its motion.

With the move towards such appliances, which are more efficient and power-intensive, increasingly advanced electric motors are required, says Dr Lee. “Existing technology suffers from some inherited problems that cannot fulfill requirements for latest applications. As such, extensive research for further development on this classical technology is very important,” he explains.

However, fabricating advanced electric motors is not an easy task, even with the usage of robotic systems that are now commonplace to automate the assembly process. The most challenging part is the fabrication of metal core and permanent-magnet materials, which play a key role in the conversion of electrical energy into mechanical energy using electromagnetism.

Since moving to Singapore and joining Nanyang Technological University (NTU) two years ago, Dr Lee has worked on developing tools to tailor-make metal core and permanent-magnet materials. For example, adding metal alloys can make the materials hardier, which could be useful for situations with higher pressure or temperature.

Now an Assistant Professor at NTU’s School of Electrical & Electronic Engineering, Dr Lee is also developing 3D-printing techniques to fabricate auxiliary components in electric motors. These include the screws, frame, shield, seal and flange, which act as the glue to hold and connect the major components of an electric motor. In a bid to produce higher-performing electric motors with greater design flexibility, he wants to eventually 3D-print the metal core and permanent-magnet materials too.

These technologies will be increasingly relevant, Dr Lee explains, as more land, sea and air vehicles become electrified or hybridised (driven by a combination of electric motor and combustion engine). In fact, he and his research team are now working with global MNCs such as Rolls-Royce and Schaeffler Group to develop next-generation electric aircrafts and automated ground vehicles.

Fellowship opens new opportunities

Although electric motors have been around for years, existing research teams usually focus only on one particular area, such as electrical engineering or material science, says Dr Lee. Only a handful of research teams can afford to focus on more than research area – but Dr Lee believes that, in the development of such motors, there is a need to consider different disciplines.

In this, the NRF Fellowship offered a solution. After having successfully applied for the Fellowship last year, Dr Lee now has the resources he needs to assemble a research team involving experts from multiple disciplines – “one of the very few motor teams in the world that can afford to do so”.

He is also planning on buying more sophisticated equipment, such as a laser machine for metal customisation, which is seldom seen in material science and motor laboratories. The resources will be channelled towards solving problems in electric vehicles: for example, the team hopes to develop customised materials and components to enhance the performance of electric motors, such as a gearless structure to replace mechanical gearboxes – which are subject to poor lubrication, misalignment, or wear and tear – in existing electric vehicles.

With the support of the Fellowship, Dr Lee has high hopes for the future. “I’m confident that five years from now, our team can become one of the market leaders in the motor field,” he says, adding that he hopes that the team’s research can someday be widely implemented across the world.

The NRF Fellowship is a competitive programme that provides opportunities for early career researchers to carry out independent research in Singapore. It is open to all areas of science and technology, and outstanding young scientists and researchers of all nationalities are welcome to apply. Application closes on 28 February 2020. Visit www.nrf.gov.sg/NRFfellowship for details. 

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