apl. Prof. Dr. Zhong Li
Photo: Hardy Welsch
Research Interests
(in the fields covered by the research center)
Integrating Renewable Energy Sources with Low Losses and Emissions into Dynamic Power Grids
The research deals with three areas that are important for the energy revolution: the dynamic behaviour of power grids, energy conversion and electromagnetic emissions. The rise of intelligent power networks (smart grids) requires a multi-disciplinary approach with efforts being made in a areas of power electronics, intelligent systems, and automation technology, as well as IT.
The importance of power electronics is fundamental for the development of intelligent networks using renewable and/or alternative energy sources that require high-efficiency current transformer systems, optimum energy transfer, bidirectional power flows, high reliability, synchronizability, resistance to electromagnetic interference, intelligent metering, telecommunications capabilities, fault tolerance and much more. Smart grids are, by their very nature, highly complex, non-linear dynamic networks. Monitoring and regulation are key tasks for ensuring self-repair, self-organization and self-configuration capabilities.
Complex network theory offers one promising method for addressing and simulating issues arising from network complexity such as damage susceptibility, robustness, and spontaneous behavior of power systems. Applying Z-source topology to power-electronic components is being used to develop an innovative semi-conductor that, thanks to its high-voltage level amplification, meets the requirements of photovoltaics. Solar modules with maximum power point tracking are usually connected to power grids by means of grid-connected inverters, which therefore play an important role in ensuring high quality of solar energy fed into the grids.
High-frequency switching in these inverters, however, leads to serious electromagnetic faults, especially at high ouptuts. To help with this, an innovative method is being developed for chaotic sinusoidal pulse width modulation for grid-connected inverters that offers design flexibility and low costs. The results of this work are to be validated using a micronetwork that is fed by renewable sources such as solar cells, wind turbines or energy storage systems and also involves the use of intelligent meters, new transformers, etc.
-
(in the fields covered by the research center)
- Zhang, G./Yuan, J./Li, Z./Yu, Samson/Chen, S./Trinh, H./Zhang, Y. (2020): Forming a Reliable Hybrid Microgrid Using Electric Spring Coupled with Non-sensitive Loads and ESS, in: IEEE Transactions on Smart Grid, DOI: 10.1109/TSG.2020.2970486
- Song, Y./Niu, J./Li, Z. (2019): Chaos versus EMI: Methodologies and Practice, in: International Journal of Bifurcation and Chaos, Vol. 29, No. 12, 1930033
- Zhang, G./Zhang, B./Li, Z. (2018): Designing Impedance Networks Converters, Serie “Studies in Systems, Decision and Control,” Springer International Publishing, Basel.
- Zhang, G./Li, Z./Zhang, B./Halang, W. A. (2018): Power Electronics Converters: Past, Present and Future, in: Renewable & Sustainable Energy Reviews, Vol. 81, Part 2, pp. 2028–2044.
- Zhang, G./Ho-Ching Iu, H./Zhang, B./Li, Z./Fernando, T. L./Chen, S./Zhang, Y. (2017): An Impedance Networks Boost Converter with a High-voltage Gain, in: IEEE Transactions on Power Electronics, Vol. 32, No. 9, pp. 6661–6665.
-
(in the fields covered by the research center)
- Alexander von Humboldt Research Group Linkage Programme, FernUni.-City U Hong Kong 2014-2017, „Integrating Renewable Energy Sources with Low Losses and Emissions into Dynamic Power Grids”, Prof. W. Halang, Prof. Zhong Li
- AiF-IGF-Project 17211N, Germany 2011-2013, “Unterdrückung elektromagnetischer Stör-aussendungen elektronischer Geräte durch Chaosregelung”, Prof. W. Halang, Prof. Z. Li
- Key Program of National Natural Science Foundation of China (No. 50937001) , 2010-2013, “Nicht-lineare Analyze und Regelungsstrategie in der Leistungselektronik”, Prof. B. Zhang, Prof. Z. Li
