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DESIGN AND IMPLEMENTATION OF TRANSFORMERLESS INVERTER WITH DC CURRENT ELIMINATION Guided By Dr. Sasidharan Sreedharan Presented By, SUDHIN P.K 1 PGEE02012 CONTENTS OBJECTIVE MOTIVATION LITERATURE REVIEW PROPOSED CONVERTER COMPLETE MODEL – BLOCK DIAGRAM EXPECTED OUTCOME GANTT CHART REFERENCES 2 OBJECTIVE Phase I : i. ii. Simulation : Transformerless Inverter Model Hardware implementation of Transformerless inverter (Off Grid Model) Phase II : i. ii. PLL Design Grid Integration of Developed Model 3 MOTIVATION Increasing demand of PV system Development of Cost Effective system Complete elimination of CM leakage current 4 WHY ‘LESS’ TOPOLOGY? Most Commercial PV inverters employ either linefrequency or high-frequency isolation transformers. Increases – Size,Cost,Losses Transformerless Topology – Reduced Size, weight, cost and installation complexity Increases efficiency by 2% produces Common Mode Leakage Current 5 THE COMMON MODE LEAKAGE CURRENT, increases the system losses reduces the grid connected current quality induces severe conducted and radiated electromagnetic interference causes personal safety problems. 6 7 Literature Review Full H Bridge Topology [5] I. Simple Structure II. High EMI III. High Common mode Leakage Current Half H Bridge Topology [5] I. Simple Structure II. High EMI III. High Common mode Leakage Current IV. High Voltage Stress across switches 8 HERIC Topology [6] H5 Topology [7] I. I. Large number of Switches Less number of Switches II. Low EMI II. Low EMI III. Low Common mode Leakage Current III. Low Common mode Leakage Current 9 PROPOSED TOPOLOGY : CONCEPT 10 PROPOSED TOPOLOGY 11 COMPARISON WITH PATENTED TOPOLOGIES HERIC (Sunways) H5 Topology (SMA) Proposed Topology Input Capacitors 1 1 1 (but one additional switched capacitor) Input Capacitance low low low Switches 6 5 5 Diodes 2 0 0 No of output voltage Levels 3 3 3 Leakage Current Very Low Very Low Nil 12 COMPLETE MODEL 12/24 V (DC) DC-DC CONVERTER (MPPT) Triggering Pulses MICRO CONTROLLER Vpv,Ipv 400 V (DC) TRANSFORMERLESS INVERTER 220 V (AC) LOAD/ GRID Triggering Pulses (SPWM) MICRO CONTROLLER 13 EXPECTED OUTCOME Simulation and Hardware implementation of Transformerless Inverter with complete DC current elimination. Less voltage and current stress on switches in comparison with HERIC and H5 Topology 14 GANTT CHART 15 REFERENCES [1] Gu, Yunjie, Wuhua Li, Yi Zhao, Bo Yang, Chushan Li, and Xiangning He. "Transformerless Inverter with Virtual DC Bus Concept for Cost Effective Gridconnected PV Power Systems." (2013): 1-1. [2] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of single-phase gridconnected inverters for photovoltaic modules,” IEEE Trans. Ind.Appl., vol. 41, no. 5, pp. 1292–1306, Sep./Oct. 2005. [3] T. Kerekes, R. Teodorescu, P. Rodr´ıguez, G. V´azquez, and E. Aldabas, “A new high-efficiency single-phase transformerless PV inverter topology,”IEEE Trans. Ind. 16 Electron., vol. 58, no. 1, pp. 184–191, Jan. 2011. REFERENCES [4] Yang, Bo, Wuhua Li, Yunjie Gu, Wenfeng Cui, and Xiangning He. "Improved transformerless inverter with common-mode leakage current elimination for a photovoltaic grid-connected power system." Power Electronics, IEEE Transactions on 27, no. 2 (2012): 752-762. [5] Patrao, Iván, Emilio Figueres, Fran González-Espín, and Gabriel Garcerá. "Transformerless topologies for grid-connected single-phase photovoltaic inverters." Renewable and Sustainable Energy Reviews 15, no. 7 (2011): 3423-3431. [6] S. Heribert, S. Christoph, and K. Juergen, German Patent HERIC Topology,DE 10221592 A1, Apr. 2003. [7] V. Matthias, G. Frank, B. Sven, and H. Uwe, German Patent H5Topology,DE 102004030912 B3, Jan. 2006. 17