Applications of Perturbation Theory to Power Electronic Converters
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Mathematical Sciences
Abstract
This project aims to develop advanced mathematical modelling approaches to predict instability and define actions to mitigate the risk of undesired behaviours of networks of power converters. The ideal outcome of this project is the development of a generalised modelling and stability assessment framework. In general, renewable energy sources are interfaced to the main grid by power electronic converters. The method implemented in this research will be used to predict the impact on stability of a power-electronics-based generator, as well as to assess the capability of network to accommodate multiple generators of this kind. Theoretical findings will be validated in simulation and on laboratory-scale experiments representative of practical application scenarios.
Organisations
People |
ORCID iD |
| Stephen Cox (Primary Supervisor) | |
| Marta Laterza (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N50970X/1 | 30/09/2016 | 29/09/2021 | |||
| 1951105 | Studentship | EP/N50970X/1 | 30/09/2017 | 30/03/2021 | Marta Laterza |
| Description | Stability assessment of electrical grids is now growing in complexity due to the shift from centralised production, based on fossil fuels and nuclear, to microgrids, small autonomous regions based on distributed generation from renewable sources. A microgrid is a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. Renewable sources are generally interfaced to the main grid by power electronic converters, silicon-based high-frequency switching devices which convert electrical power from DC to AC and vice versa. Due to their negligible physical inertia, power electronic converters are flexible in operation, but susceptible to oscillations and network disturbances. To prevent instability, they require relatively complex controllers including multiple nested loops. Stability analysis of such systems can become computationally challenging due to the high number of variables and nonlinearities, in particular when big systems or multiple devices are involved. In the engineering literature, some ad hoc approximations are usually applied to deal with these complexities. This work aimed to apply mathematical methods to power electronic systems, in order to model effectively electrical grids based on distributed generation, reduce the order of the system systematically and evaluate the system stability. A systematic reduction method based on nonlinearisation and perturbation theory has been found to work well on models for electrical systems composed by a small number of converters (1-3) and resistive loads. Full and reduced systems show a good agreement in terms of stability analysis. Reduced systems have approximately 50-60% fewer variables and ordinary differential equations than the full ones. |
| Exploitation Route | Further reductions of the same systems can be evaluated. Bigger and more complex systems could be analysed and eventually reduced through the same methods. |
| Sectors | Electronics Energy Environment Transport |