Comparison between 2-level and 3-level grid connected inverters implemented using SRF PLL technique

In recent days in order to have effective utility of Renewable Energy (RE) Resources, they are being integrated to the Grid through a power converter. So, the grid side inverter control of RE systems is one of the main issues in power production units besides that, the voltages and the currents that are being feed to the grid must be free from harmonics and they should have the same phase angle as that of the grid. The THD of the inverter output voltage can be reduced by increasing the step level of the inverter topology. In this paper a comparative study between the 2-level & 3-level inverters that are interconnected to the grid is studied by using the SRF-PLL technique and the results have shown that the amount of THD for the 3-level topology is less, compared to that of the 2-level topology.

[1]  Vinod John,et al.  A Method to Improve PLL Performance Under Abnormal Grid Conditions , 2007 .

[2]  Hyosung Kim,et al.  Filter design for grid connected PV inverters , 2008, 2008 IEEE International Conference on Sustainable Energy Technologies.

[3]  V. Blasko,et al.  Operation of a phase locked loop system under distorted utility conditions , 1997 .

[4]  M. Liserre,et al.  Design and control of an LCL-filter based three-phase active rectifier , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[5]  J. Arai,et al.  Power electronics and its applications to renewable energy in Japan , 2008, IEEE Circuits and Systems Magazine.

[6]  J. Schlabbach,et al.  Voltage Quality in Electrical Power Systems , 2001 .

[7]  Rickard Ekström.  Inverter System Design and Control for a Wave Power Substation , 2009 .

[8]  B.R.J. Caunce,et al.  Flexible AC transmission systems [Book Reviews] , 2000 .

[9]  P. Ashmole,et al.  Flexible AC transmission systems , 1995 .

[10]  S.V. Araujo,et al.  LCL filter design for grid-connected NPC inverters in offshore wind turbines , 2007, 2007 7th Internatonal Conference on Power Electronics.

[11]  E. Ortjohann,et al.  Challenges in integrating distributed Energy storage systems into future smart grid , 2008, 2008 IEEE International Symposium on Industrial Electronics.