Design of Flyback Micro-inverter for Grid Connected Photovoltaic Systems

Abstract

The flyback micro-inverters operating at discontinuous conduction mode are very attractive due to the operation in open loop and working without current sensor. In this paper, the working characteristics of a grid-connected photovoltaic micro-inverter based on flyback converter are investigated and design details are presented. “Perturbation and observation” method is used for maximum power point tracking. A micro-inverter prototype of 80 Wp is designed and produced. All the inverter functions, such as maximum power point tracking, islanding protection, serial communication, power control etc., are implemented by PIC24FJ64GA002 microcontroller. The measurements taken from protyped micro-inverter are compatible with design values. The highest efficiency of the converter was found as 80% and the loss mechanisms are discussed.

Keywords

• Maximum power point tracking, Grid connected flyback micro-inverter

Şebekeye Bağlı Fotovoltaik Sistemler İçin Flyback Mikro-evirici Tasarımı

Abstract

Kesikli iletim kipinde çalışan flyback mikro-eviriciler açık çevrim kontrol edilebilmeleri ve akım algılayıcısı olmadan çalışabilmeleri nedeniyle oldukça ilgi görmektedirler. Bu makalede flyback dönüştürücü tabanlı şebekeye bağlı bir fotovoltaik mikro-eviricinin çalışma karakteristikleri incelenmiş ve tasarım detayları verilmiştir. Maksimum güç noktası izleme için “değiştir ve gözle” algoritması kullanılmıştır. 80 Wp gücünde bir prototip mikro-eviricinin tasarımı yapılmış ve üretilmiştir. Maksimum güç noktası izleme, adalama koruması, seri haberleşme, güç kontrolü gibi eviricinin bütün kontrolleri PIC24FJ64GA002 mikrodenetleyicisi ile gerçekleştirilmiştir. Mikro-eviriciden alınan ölçümlerin tasarım değerleriyle uyumlu olduğu görülmüştür. Tasarlanan eviricinin maksimum verimi %80 olarak ölçülmüş ve oluşan kayıpların nedenleri irdelenmiştir.

Keywords

• Maksimum güç noktası izleme, Şebekeye bağlı flyback mikro-evirici

References

1. Dinçer F. "The Analysis on Photovoltaic Electricity Generation Status, Potential and Policies of the Leading Countries in Solar Energy”. Renewable and Sustainable Energy Reviews, 15(1), 713-720, 2011.
2. International Energy Agency. “Photovoltaic Power System Programme (PVPS)”, International Energy Agency, Annual Report, 2010.
3. European Photovoltaic Industry Association. “Solar Generation V-Solar Electricity for Over one Billion People and two Million Jobs by 2020”, European Photovoltaic Industry Association Report, Brussels, Belgium, 73, 2009.
4. Kaundinya DP, Balachandra P, Ravindranath NH. “Grid-Connected Versus Stand-Alone Energy Systems for Decentralized Power-A Review of Literature”. Renewable and Sustainable Energy Reviews, 13(8), 2041-2050, 2009.
5. Çekinir S, Boztepe M. “A Comparative Analysis of Grid-connected PV System Topologies”. 5th International Ege Energy Symposium and Exhibition, Denizli, Turkey, 27-30 June 2010.
6. Kjaer SB, Pedersen JK, Blaabjerg F. “A Review of Single- Phase Modules”. IEEE Transactions on Industry Applications, 41(5), 1292-1306, 2005. Inverters for Photovoltaic
7. Xue Y, Chang L, Kjær SB. “Topologies of Single-Phase Inverters for Small Distributed Power Generators : An Overview”. IEEE Transsactions on Power Electronics, 19(5), 1305-1314, 2004.
8. Li Q, Wolfs P. “A Review of the Single Phase Photovoltaic Module Integrated Converter Topologies With Three Different DC Link Configurations”. IEEE Transactions on Power Electronics, 23(3), 1320-1333, 2008.

9. Kyritsis AC, Tatakis EC, Papanikolaou NP. “Optimum Design of the Current-Source Flyback Inverter for Decentralized Grid-Connected Photovoltaic Systems”. IEEE Transactions on Energy Conversion, 23(1), 281-293, 2008.
10. Zengin S, Deveci F, Boztepe M. “Decoupling Capacitor Selection in DCM Flyback PV Microinverters Considering Harmonic Distortion”. IEEE Transactions on Power Electronics, 28(2), 816–825, 2013.
11. Sharma R. “Switching Frequency Filter Design for Utility Connected PV Inverters”. Australasia Universities Power Engineering Australia, 29th September to 2nd October 2002. Proceedings, Melbourne,
12. Esram T, Chapman PL. “Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques”. IEEE Transactions on Energy Conversion, 22(2), 439-449, 2007.
13. Wu TF, Chang CH, Chang YD, Lee KY. “Power Loss Analysis of 2009 International Conference on Power Electronics and Drive Systems (PEDS 2009), Taipei, Taiwan, 2-5 November 2009. Photovoltaic System”.