DESIGN AND IMPLEMENTATION OF TRANSFORMERLESS INVERTER WITH DC CURRENT ELIMINATION Presented By, SUDHIN P.K PGEE02012 Guided By Dr. Sasidharan Sreedharan 1

CONTENTS OBJECTIVE MOTIVATION LITERATURE REVIEW PROPOSED CONVERTER COMPLETE MODEL – BLOCK DIAGRAM EXPECTED OUTCOME GANTT CHART REFERENCES 2

OBJECTIVE Phase I : i. Simulation : Transformerless Inverter Model ii. Hardware implementation of Transformerless inverter (Off Grid Model) Phase II : i. PLL Design ii. 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 line- frequency 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

T HE 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

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Full H Bridge Topology [5]Half H Bridge Topology [5] I.Simple Structure II.High EMI III. High Common mode Leakage Current I.Simple Structure II.High EMI III. High Common mode Leakage Current IV. High Voltage Stress across switches Literature Review 8

HERIC Topology [6]H5 Topology [7] I.Large number of Switches II.Low EMI III. Low Common mode Leakage Current I.Less number of Switches II.Low EMI III. Low Common mode Leakage Current 9

P ROPOSED TOPOLOGY : C ONCEPT 10

P ROPOSED TOPOLOGY 11

C OMPARISON WITH P ATENTED T OPOLOGIES HERIC (Sunways) H5 Topology (SMA) Proposed Topology Input Capacitors 11 1 (but one additional switched capacitor) Input Capacitance low Switches 655 Diodes 200 No of output voltage Levels 333 Leakage Current Very Low Nil 12

C OMPLETE MODEL DC-DC CONVERTER (MPPT) TRANSFORMER- LESS INVERTER LOAD/ GRID MICRO CONTROLLER MICRO CONTROLLER 12/24 V (DC) 400 V (DC) 220 V (AC) V pv,I pv Triggering Pulses Triggering Pulses (SPWM) 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 Grid- connected PV Power Systems." (2013): 1-1. [2] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of single-phase grid- connected inverters for photovoltaic modules,” IEEE Trans. Ind.Appl., vol. 41, no. 5, pp. 1292–1306, Sep./Oct [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. Electron., vol. 58, no. 1, pp. 184–191, Jan

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): [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): [6] S. Heribert, S. Christoph, and K. Juergen, German Patent HERIC Topology,DE A1, Apr [7] V. Matthias, G. Frank, B. Sven, and H. Uwe, German Patent H5- Topology,DE B3, Jan