Modular Multilevel Converters for Medium Voltage Applications

The Power Electronics research team from the School of Engineering at the University of Edinburgh is now looking to a recruit a high calibre PhD candidate to work on the topic of Modular Multilevel Converters; their design, control, operation and general optimization. This project aims to transpose the modular power converters outside of their inceptual HVDC market into medium voltage ratings where their positive characteristics (e.g. high waveform quality, high power efficiency) can support the increase in demand for power conversion applications, typically in distribution networks and electric drives. This means that aspects such as power density, passive and active components, overall power efficiency, control systems, and performance under widely-varying conditions must be thoroughly re-examined.

Over the two last decades, Modular Multilevel Converters have revolutionised the HVDC sector, delivering scalable, highly controllable converter structures, which reach higher performances in terms of waveform quality and power efficiency. In fact, the HVDC environment provided to power electronics engineers the ideal ground for fundamentally changing the paradigm of power converter design. The extreme voltage levels processed by HVDC converters impose the use of thousands of the highest rating power semiconductor devices. This environment meant that large research efforts have been put on the electrical arrangement of all these devices, ultimately resulting in the inception of a new building block, called Sub-Modules (SM). SMs can be stacked, yet individually controlled forming modular power converters able to generate high quality waveforms at high power efficiency.

This PhD project consists in studying the state-of-the-art modular power converter technology applied to medium voltage applications, e.g. 10 kV. The research will identify key application areas and potential gains from the use of modular power converters, and address key barriers (e.g. number of levels, SM voltage, or modulation strategy) to their adoption. This project will include the development of new power electronics designs and converter operating principles based on Modular Power Converter technology. The objective is to bring some of the benefits of modular technology into medium voltage applications while aiming for low overall volume, high power efficiency, good thermal management, low EMI emission, and fault-resilient operation.

Further Information: 

The School of Engineering at Edinburgh has been recently ramping up its power electronics activity. This new research activity integrates ideally with the strong legacy of work done on renewable energy and machine design, carried out within the Institute for Energy Systems. The supervisor, Dr Michaël M.C. Merlin, joined the University of Edinburgh in August 2018 after 10 years at Imperial College London. There, he researched on the topic of high voltage modular power converters, working closely with GE Grid Solutions (formerly Alstom Grid), developing new converter technology and bespoke extensive control algorithms, and published several journal publications and joint patents.

The successful applicant will be expected to be knowledgeable or at least a keen interest in the concepts of electrical power engineering, power electronics, control theory, power electronic design and electronic lab environment. This research project will be involved mathematical modelling, simulation-based testing, hardware design and experimental verification.

Closing Date: 

Friday, July 6, 2018
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Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in electronics, electrical engineering or a relevant science, possibly supported by an MSc Degree. Skills in MATLAB, Simulink, PSpice, advanced control theory, thermal modelling, EMI are highly desirable but not essential. Applicants must be enthusiastic and highly motivated to learn and work across traditional discipline boundaries.

Further information on English language requirements for EU/Overseas applicants.


Tuition fees and stipend are available for Home/EU students. International students can apply, but the funding only covers the Home/EU fee rate. Applications are also welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhere.

Further information and other funding options.

Informal Enquiries: