Cascaded Voltage Control of Three-Phase Four-Leg Inverter for OFF Grid Solar Photovoltaic Applications
Solar photovoltaics (PV) is one of the popular renewable energy sources in tropical countries like India which can help in supplementing the rising demand of electrical energy. DC input from solar PV strings needs to be converted into AC component both for ON and for OFF grid applications. Three-phase inverters are used for the above inversion when power levels are high. In OFF grid applications, task of maintaining stable terminal voltage across the loads lies with the inverter in the absence of utility grid. It also has to supply variety of balanced and unbalanced loads. In this paper, cascaded voltage control scheme, for a three-phase four-leg inverter, is developed. Parameters of the proportional resonant controllers (PR) are tuned using bode plot techniques. Simulations results are presented for operation under different loading conditions.
KeywordsCascaded voltage control Four-leg inverter PR controller Solar inverter
The authors express their gratitude to Council of Scientific and Industrial Research (CSIR), New Delhi, for funding this project under TAPSUN program.
- 1.Akhtar, M.A., Ikkurti, H.P.: A new controller for maximum power extraction from photovoltaic system using phase modulated converter. In: Proceedings of IEEE International Conference on Advances in Power Conversion and Energy Technologies, pp. 1–6. Andhra Pradesh, India (2012)Google Scholar
- 2.Zhang, R., Boroyevich, D., Prasad, V.H., Mao, H.C., Lee, F.C., Dubovsky, S.: A three-phase inverter with a neutral leg with space vector modulation. In: Proceedings of Twelfth Annual Applied Power Electronics Conference and Exposition, vol. 2, pp. 857–863 (1997)Google Scholar
- 3.Griffith, D.C.: Neutral wire current monitoring for three-phase four-wire power distribution system. Patent US 5182547A (1993)Google Scholar
- 6.Zhang, R.S.: High performance power converter systems for nonlinear and unbalanced load/source. Ph.D. Dissertation, Virginia Polytechnic Institute and State University (1998)Google Scholar
- 8.De, D., Ramanarayanan, V.: A proportional multiresonant controller for three-phase four-wire high-frequency link inverter. IEEE Trans. Power Electron. 25(4), 899–906 (2010)Google Scholar
- 9.Demirkutlu, E., Çetinkaya, S., Hava, A.M.: Output voltage control of a four-leg inverter based three-phase UPS by means of stationary frame resonant filter banks. In: Proceedings of IEEE International Electric Machines & Drives Conference, vol. 1, pp. 880–885. Antalya-Turkey (2007)Google Scholar