PhD, Indian Institute of Technology Bombay
Traditional distribution grids are becoming more and more smart. In a smart grid, there will be more customer participation, large scale integration of renewable at the customer site, formation of micro grids etc. This would require the traditional 50/60 Hz distribution transformer to be replaced by more sophisticated (intelligent) transformer to route the power efficiently. This new transformer should have all the functionalities of the traditional transformer apart from having its own intelligence to provide ancillary services to the grid. It employs of power electronic converters and medium frequency transformer to achieve the functionalities like high power density, intelligent power management etc.
Abstract: A novel method for real-time small-signal stability analysis for power electronic-based components in a power system. The method is based on impedance measurement techniques and Generalized Nyquist Criterion. The method is capable of real-time application. The method may be used to monitor a system in real-time by perturbing the system persistently and utilizing the system's responses to calculate source/load impedance in time-domain and based on d-q impedance measurement theory. Time-domain results may be transferred to frequency-domain results by taking advantage of a fast Fourier transform algorithm (or optionally discrete Fourier transformer for discrete systems) and monitoring the system's stability by obtaining a Nyquist contour and employing Generalized Nyquist Criterion or unit circle criterion.
Pub.: 19 Apr '16, Pinned: 27 Jul '17
Abstract: An AC-AC Converter for an AC source which in one embodiment has a first rectifier section rectifying the AC source into a first pulsed DC link voltage signal and a high frequency modulating section coupled to the first pulsed DC link voltage signal and producing a high frequency AC voltage signal. A high frequency transformer is coupled to the high frequency AC voltage signal producing a transformed high frequency AC signal. There is a second rectifier section coupled to the transformed high frequency AC signal and producing a second pulsed DC voltage signal and an unfolder section coupled to the second pulsed DC voltage signal and producing an output AC signal.
Pub.: 04 Feb '14, Pinned: 27 Jul '17
Abstract: The present invention relates to an energy router for an energy internet, which comprises a three-phase three-level bi-directional rectifying unit, a six-phase interleaved DC/DC bi-directional conversion unit, a self-excitation soft start push-pull full-bridge DC/DC bi-directional conversion unit, a three-phase resonant soft switching bi-directional inversion unit, a single-phase full-bridge bi-directional inversion unit, a high-voltage DC bus and a low-voltage DC bus. The three-phase three-level bi-directional rectifying unit, the six-phase interleaved DC/DC bi-directional conversion unit, the self-excitation soft start push-pull full-bridge DC/DC bi-directional conversion unit, the three-phase resonant soft switching bi-directional inversion unit and the single-phase full-bridge bi-directional inversion unit each have three energy flow operating modes: a forward conduction, a reverse conduction and a non-conduction. According to the energy flow operating mode of each unit, different operating modes of the energy router for the energy internet are formed.
Pub.: 07 Feb '17, Pinned: 27 Jul '17
Abstract: Publication date: February 2017 Source:International Journal of Electrical Power & Energy Systems, Volume 85 Author(s): Yong Li, Jiye Han, Yijia Cao, Yunxuan Li, Jiamin Xiong, Denis Sidorov, Daniil Panasetsky To overcome the limitation of the existing topologies and control strategies of SST, a modular multilevel converter type solid state transformer (MMC-SST) with internal model control method is proposed in this paper. First, the structure and operating characteristics of MMC-SST are analyzed, and accordingly its mathematical model of input- and output-stage under synchronous rotating coordinate is established. Secondly, a new kind of dual-loop control structure combine with the internal model control (IMC) current inner loop and proportional integral (PI) voltage outer loop is developed, according to the characteristics of IMC. Lastly, a simulation model is established and the typical operating cases, i.e., the grid side voltage variation, load change, grid and load side power factor deviation, are simulated. Results show that the internal model control based MMC-SST can run stable under the required power factor, and the good performances such as fast voltage and current response speed, strong anti-disturb ability to load, and enhanced robustness on system operation are demonstrated.
Pub.: 24 Sep '16, Pinned: 27 Jul '17
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