Prof. De Doncker and Jingxin Hu visit the IEEE IFEEC-ECCE Asia conference in Kaohsiung, Taiwan
During June 3rd – 7th, Professor De Doncker and Jingxin Hu visited the IEEE IFEEC-ECCE Asia 2017 conference held in Kaohsiung, Taiwan. Professor De Doncker was invited to give a keynote speech on the topic of “Power Electronics – key enabling technology for a CO2 neutral electrical energy supply”. Meanwhile Jingxin Hu presented his paper “A Duty-Cycle Control Method to Ensure Soft-Switching Operation of a High-Power Three-Phase Dual-Active Bridge Converter”. The abstracts of the speech and the paper will be presented in the following.Copyright: © Jingxin Hu
Power Electronics – key enabling technology for a CO2 neutral electrical energy supply
Prof. Dr.ir. Dr.h.c. Rik W. De Doncker
Awareness of global climate change due to the high consumption of fossil fuels and the expectation of cost increases of primary energy sources in the coming decades has stimulated worldwide research and innovation towards a CO2-free energy environment. To realize this “Energiewende”, i.e. energy transformation, research, development and innovation is required both on the energy supply and the consumption side, as well as on flexible grids and storage systems.
The speaker focuses on key enabling technologies that are pursued in research programs, in particular in Germany and Europe, to prepare the electrical supply system and the grid for an increased use of more decentralized and more volatile, renewable power sources at all voltage levels, i.e. high-voltage transmission, medium- and low-voltage distribution level. As research is not only focused on electrical grids and electrochemical storage systems, but also on low- and high-temperature heat and gas storage systems for medium- and long-term storage capacities, efficient energy conversion systems are required. Such storage systems can already be found as “dual use” storages in buildings, heating, ventilation and air-conditioning systems, in demand side energy management systems for buildings and homes, in the electrification of transportation, most notably in electric vehicles. In all these areas, power electronic energy conversion systems will be used. For such scenario, the speaker will highlight the advantages of DC technology to help future grids to become more efficient, flexible and cost effective.
A Duty-Cycle Control Method to Ensure Soft-Switching Operation of a High-Power Three-Phase Dual-Active Bridge Converter
Jingxin Hu, Zhiqing Yang, Nils Soltau, Rik W. De Doncker
In this paper, a symmetrical duty-cycle control (SDCC) method for a three-phase dual-active bridge (DAB3) converter with snubber capacitors is proposed to ensure the zero-voltage switching (ZVS) operation over the whole operation range. Closed-form expressions for the proposed modulation scheme are derived. Furthermore, the equivalent circuit and mathematical model of the converter commutation process are presented and analyzed, based on which an analytical method to determine a suitable deadtime is given. Moreover, the minimum current for a successful commutation is suggested. Based on the simulation results of a 5MW DAB3 converter with a 1 μF snubber capacitor in parallel to each device, the proposed commutation-current-constrained SDCC method ensures the soft-switching operation over the whole operation range with obsolete auxiliary circuits. Applying the switching optimized IGCT devices, the DAB3 converter achieves a high efficiency of 96.5% to 99.2% for a wide operation range.