Phasor Control of Converter Output Voltage for Frequency Regulation

Masahide Hojo, Ryo Ikeshita, Yoshinobu Ueda, Toshihisa Funabashi

EcoTopia Science Institute, Nagoya University, Nagoya, Japan.
Institute of Technology and Science, The University of Tokushima, Tokushima, Japan.
Power Utility Sector Business Unit, Meidensha Corporation, Tokyo, Japan.

DOI: 10.4236/jpee.2014.27003                

Abstract

The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by synchronizing their output voltage with the one at the point of common coupling. In the circumstances, a concept of Virtual Synchronous Machine (VSM) is proposed, where the self-commutated power converters are emulating synchronous generators. This paper describes a converter control to contribute to enhancing the synchronizing torque. The proposed control is similar to the VSM but it simply realizes active power trades among power generation units including converter-based generators by modulating phase angles of their output voltages. Therefore, it can provide an effective support to regulate the system frequency where the total rated power of the converter-based generators increases as much as the one of conventional rotating generators like a microgrid. This paper especially focuses on its robustness where the number of converter-based generators is increased or they are dispersed in the power network. The effectiveness is verified by simulation study based on instantaneous values.

Keywords

Self-Commutated Power Converter, Synchronous Generator, Frequency Control, Voltage Phasor

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Beck, H.P. and Hesse, R. (2007) Virtual Synchronous Machine. International Conference on Electrical Power Quality and Utilization, Barcelona, 9-11 October 2007, 6 p.
[2]	Visscher, K. and Haan, S.W.H. (2008) Virtual Synchronous Machines (VSG’s) for Frequency Stabilization in Future Grids with a Significant Share of Decentralized Generation. CIRED Seminar 2008: Smart-Grids for Distribution, Frankfurt, 23-24 June 2008, 0118.
[3]	Sakimoto, K., Sugimoto, K. and Shindo, Y. (2013) Low Voltage Ride through Capability of a Grid Connected Inverter Based on the Virtual Synchronous Generator. Proceedings of the IEEE 10th International Conference on Power Electronics and Drive Systems, Kitakyushu, 22-25 April 2013, 1066-1071.
[4]	Alipoor, J., Miura, Y. and Ise, T. (2014) Voltage Sag Ride-Through Performance of Virtual Synchronous Generator. Proceedings of the 2014 International Power Electronics Conference—ECCE, Hiroshima, 18-21 May 2014, 3298-3305.
[5]	Liu, J., Miura, Y. and Ise, T. (2014) Dynamic Characteristics and Stability Comparisons between Virtual Synchronous Generator and Droop Control in Inverter-Based Distributed Generators. Proceedings of the 2014 International Power Electronics Conference—ECCE, Hiroshima, 18-21 May 2014, 1536-1543.
[6]	Hojo, M., Ikeshita, R., Terauchi, T., Ueda, Y. and Funabashi, T. (2011) A Converter Controller of Virtual Synchronous Machine for Stable Operation of Microgrid. Conference Proceedings of 21th International Conference and Exhibition on Electricity Distribution (CIRED), Frankfurt, 6-9 June 2011, 0535.