The Doubly-Fed Induction Generator (DFIG) is one of the most popular and widely used technologies for wind power applications with limited variable speed ranges (e.g. 2:1 or so) due to its good overall performance and a low cost partially-rated (typically 30%) power electronics converter. However, the significant maintenance requirements of the brushes and slip rings, the high failure rates of the high-speed (3rd) stage of a gearbox, and consequent costly drive train downtimes (especially in off-shore installations), as well as the grid-code compliance issues under faulty operating conditions, are notable disadvantages of the DFIGs compared to synchronous generators. This fact has led to increasing interests in reliable, maintenance-free, brushless doubly-fed counterparts (BDFGs), which can largely overcome these DFIG drawbacks whilst still retaining the cost-effectiveness of the fractional converter rating and the benefits of decoupled field oriented control. The main BDFG advantages over the DFIG are the absence of brush gear, its medium speed nature allowing the use of a simpler, more compact 1-2 stage gearbox, and proportionally lower fault current magnitudes, and hence facilitated converter protection circuitries, afforded by the relatively higher leakage inductances.
In this project, a comparative control development and grid integration studies of a promising BDFG reluctance rotor version, the Brushless Doubly-Fed Reluctance Generator (BDFRG), and a similarly rated DFIG will be undertaken for performance comparisons. Realistic computer simulations using specialist software will be done at a large-scale (MW) level, whereas the existing laboratory test facilities for emulation of wind energy conversion systems based on each generator type will be used for the experimental work. Both normal and abnormal operation of the DFIG/BDFRG and their grid connection aspects including maximum power point tracking, low voltage ride through properties and/or frequency support capabilities, will be thoroughly addressed and investigated.
Given the scope and demands of the project, we are expecting one or two prospective PhD students to take part. Knowledge of the fundamental theory, dynamic modelling and power electronics control of electrical machines (doubly-excited in particular), digital signal processing and/or high-level computer programming would be preferable. The successful candidate(s) would be associated with the reputable Electrical Power and Control Systems research group.
Please note eligibility requirement:
* Academic excellence of the proposed student i.e. 2:1 (or equivalent GPA from non-UK universities [preference for 1st class honours]); or a Masters (preference for Merit or above); or APEL evidence of substantial practitioner achievement.
* Appropriate IELTS score, if required
For further details of how to apply, entry requirements and the application form, see https://www.northumbria.ac.uk/research/postgraduate-research-degrees/how-to-apply
Please note: Applications that do not include a research proposal of approximately 1,000 words (not a copy of the advert), or that do not include the advert reference (e.g. SF18/MPEE/JOVANOVIC) will not be considered.
Start Date: 1 March 2019 or 1 June 2019 or 1 October 2019
Northumbria University takes pride in, and values, the quality and diversity of our staff. We welcome applications from all members of the community. The University hold an Athena SWAN Bronze award in recognition of our commitment to improving employment practices for the advancement of gender equality and is a member of the Euraxess network, which delivers information and support to professional researchers.
 F. Zhang, S. Yu., Y. Wang, S. Jin, M. G. Jovanovic, “Design and Performance Comparisons of Brushless Doubly-Fed Generators with Different Rotor Structures”, IEEE Transactions on Industrial Electronics, Vol. 66, No. 1, pp. 631-640, 2019.
 F. Zhang, H. Wang, G. Jia, D. Ma, M. G. Jovanovic, “Effects of design parameters on performance of brushless electrically-excited synchronous reluctance generator”, IEEE Transactions on Industrial Electronics, Vol. 65, No. 11, pp. 9179-9189, Nov. 2018.
 M. Cheng, P. Han, G. Buja, M. G. Jovanović, “Emerging Multi-Port Electrical Machines and Systems: Past Developments, Current Challenges and Future Prospects”, invited guest editorial paper, IEEE Transactions on Industrial Electronics, Vol. 65, No. 7, pp. 5422–5435, July 2018.
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 S. Ademi and M. Jovanovic, "High-Efficiency Control of Brushless Doubly-Fed Machines for Wind Turbines and Pump Drives", Energy Conversion and Management, Elsevier, Vol. 81, pp. 120-132, May 2014.