Design of a D Q Axis Controlled Micro Inverter with Flyback Converter for Grid Connected PV Systems

Abstract

Inverters are one of the most important components of photovoltaic (PV) systems. Inverters are utilized as an operational interface between PV panels and the power grid or residential applications. In order to provide high system efficiency and reliable power transfer from PV panels, intensive studies have been conducted on the power circuit topologies and control structures of these inverters. In this paper, a two-stage grid-connected microinverter is designed. There is a flyback converter on the DC-DC side and a full-bridge inverter structure on the DC-AC side. The designed microinverter has the ability to amplify the input voltage. The DC voltage amplified at the inverter output is converted at the output of the microinverter to be suitable for the grid. The flyback converter is controlled by a maximum power point tracking (MPPT) algorithm and a PI controller. On the other side, the full-bridge inverter section is controlled by a D-Q axis controller. The system response is analyzed under different irradiance values. The control structures created in the designed microinverter accurately tracked the maximum power point, and maximum power transfer to the grid is observed according to different irradiance values.

Keywords

• Photovoltaic panel
• maximum power point tracking
• flyback converter
• microinverter
• D-Q axis control

Şebekeye Bağlı FV Sistemler için Flyback Dönüştürücülü D-Q Eksen Kontrollü Mikro Evirici Tasarımı

Abstract

Fotovoltaik (FV) sistemlerin en önemli bileşenlerinden biri eviricilerdir. Eviriciler FV paneller ile elektrik şebekesi veya konut uygulamaları arasında operasyonel bir arayüz görevi görmeleri nedeniyle kullanılmaktadır. Yüksek sistem verimliliği ve FV panellerden güvenilir güç aktarımı sağlanması için bu eviricilerin güç devresi topolojileri ve kontrol yapılarına yönelik yoğun çalışmalar yapılmaktadır. Bu makalede iki aşamalı şebekeye bağlı bir mikroevirici tasarımı yapılmıştır. DC-DC tarafında flyback dönüştürücü, DC-AC tarafında ise tam köprü evirici yapısı bulunmaktadır. Tasarlanan mikroevirici giriş voltajını yükseltme kabiliyetine sahiptir. Çevirgeç çıkışında yükseltilen DC gerilim mikroevirici çıkışında şebekeye uygun olacak şekilde dönüştürülmüştür. Flyback dönüştürücü maksimum güç noktası takibi (MGNT) algoritması ve PI kontrolör ile kontrol edilmiştir. Diğer yandan tam köprü evirici bölümü D-Q eksenli kontrolör ile kontrol edilmektedir. Sistem tepkisi farklı ışınım değerleri altında test edilmiştir. Tasarlanan mikroeviricide oluşturulan kontrol yapıları sayesinde maksimum güç noktası doğru bir şekilde izlenmiş ve farklı ışınım değerlerine göre şebekeye maksimum güç aktarımının sağlandığı gözlemlenmiştir.

Keywords

• Fotovoltaik panel
• maksimum güç noktası takibi
• flyback dönüştürücü
• mikroevirici
• D-Q eksenli kontrol

References

1. [1] C. L. Trujillo, F. Santamaría, and E. E. Gaona, “Modeling and testing of two-stage grid-connected photovoltaic micro-inverters,” Renew. Energy, vol. 99, pp. 533–542, Dec. 2016.
2. [2] M. Barghi Latran and A. Teke, “Investigation of multilevel multifunctional grid connected inverter topologies and control strategies used in photovoltaic systems,” Renew. Sustain. Energy Rev., vol. 42, pp. 361–376, 2015.
3. [3] Ö. Çelik, A. Teke, and A. Tan, “Overview of micro-inverters as a challenging technology in photovoltaic applications,” Renew. Sustain. Energy Rev., vol. 82, pp. 3191–3206, Feb. 2018.
4. [4] H. A. Sher and K. E. Addoweesh, “Micro-inverters — Promising solutions in solar photovoltaics,” Energy Sustain. Dev., vol. 16, no. 4, pp. 389–400, Dec. 2012.
5. [5] Ö. Çelik, “Controller design and experimental verification of grid-connected microinverters for photovoltaic applications,” Ph.D. dissertation, Dept. Elect. and Electr. Eng., Çukurova Univ., Adana, Turkey, 2019.
6. [6] L. Hassaine, E. Olias, J. Quintero, and V. Salas, “Overview of power inverter topologies and control structures for grid connected photovoltaic systems,” Renew. Sustain. Energy Rev., vol. 30, pp. 796–807, 2014.
7. [7] R. Hasan, S. Mekhilef, M. Seyedmahmoudian, and B. Horan, “Grid-connected isolated PV microinverters: A review,” Renew. Sustain. Energy Rev., vol. 67, pp. 1065–1080, Jan. 2017.
8. [8] B. Hükümen, “Geniş giriş gerilimi aralıklı solar mikro evirici tasarımı ve uygulaması,” M.S. thesis, Dept.Elect. and Electr. Eng., Karabük Univ., Karabük, Turkey, 2024.

9. [9] R. Hasan and S. Mekhilef, “Highly efficient flyback microinverter for grid-connected rooftop PV system,” Sol. Energy, vol. 146, pp. 511–522, Apr. 2017.
10. [10] R. Z. B. R. Umar, “High efficiency photovoltaic grid connected flyback microinverter,” Ph.D. dissertation, Institute for Advanced Studies, Malaya Univ., Kuala Lumpur, Malezya, 2023.
11. [11] F. Ronilaya et al., “A Phase-based Control Method to Control Power Flow of a Grid-connected Solar PV through a Single Phase Micro-inverter,” Int. J. Renew. Energy Res., vol. 10, no. v10i2, pp. 912–921, 2020.
12. [12] M. H. Rezaei and M. Akhbari, “Power decoupling capability with PR controller for Micro-Inverter applications,” Int. J. Electr. Power Energy Syst., vol. 136, no. August 2021, p. 107607, Mar. 2022.
13. [13] E. Kabalcı, “Review on novel single-phase grid-connected solar inverters: Circuits and control methods,” Sol. Energy, vol. 198, no. October 2019, pp. 247–274, 2020.
14. [14] C. Deng, M. Chen, F. Zhang, R. Zheng, and F. Jiang, “A Novel Analog Control Strategy with Simplified Implementation Scheme for Boundary Conduction Mode Flyback Microinverter,” IEEE Trans. Power Electron., vol. PP, pp. 1–13, 2025.
15. [15] C. Haliloğlu, “Şebekeye bağlı fotovoltaik sistemler için araya yerleştirilmiş flyback mikro-evirici tasarımı,” M.S. thesis, Dept.Elect. and Electr. Eng., Kahramanmaraş Sütçü İmam Univ., Kahramanmaraş, 2019.
16. [16] N. Laxmi, V. V. Kumar, and S. T. Sv, “Design and Assessment of DC-DC Interleaved Flyback Stage for Module-Integrated PV Microinverters,” 2025 IEEE 1st Int. Conf. Smart Sustain. Dev. Electr. Eng. SSDEE 2025, pp. 1–6, 2025.
17. [17] M. Tasnim, A. Sarwar, and F. I. Bakhsh, “Implementation of Flyback DC-DC Converter Topology for DC Power Supply Application,” 2025 Int. Conf. Cogn. Comput. Eng. Commun. Sci. Biomed. Heal. Informatics, IC3ECSBHI 2025, no. 3, pp. 681–686, 2025.
18. [18] S. Zengin, F. Deveci, and M. Boztepe, “Design of Flyback Micro-inverter for Grid Connected Photovoltaic Systems,” Pamukkale Univ. J. Eng. Sci., vol. 21, no. 2, pp. 30–36, 2015.
19. [19] M. Effendy, K. Hidayat, and H. N. A. Humaidi, “An Interleaved Isolated Flyback Converter with MPPT using Modified P&O Algorithm for Photovoltaic Generators,” Eng. Technol. Appl. Sci. Res., vol. 15, no. 3, pp. 22295–22300, 2025.
20. [20] N. R. B. Soham G. Deshpande, N. R. Bhasme, Soham G. Deshpande, “Modeling and Simulation of Microinverter with Flyback Converter for Grid Connected PV Systems,” Int. J. Electr. Electron. Eng. Res., vol. 7, no. 4, pp. 71–82, 2017.
21. [18] E. Kabalci and A. Boyar, “An Interleaved Flyback Micro Inverter with H5 Topology for Photovoltaic Applications,” in 2020 2nd Global Power, Energy and Communication Conference (GPECOM), Oct. 2020, pp. 12–17.
22. [19] J. F. Sultani, “Modelling, design and implementation of D-Q control in single-phase grid-connected inverters for photovoltaic systems used in domestic dwellings," Ph.D. dissertation, Faculty of Technology, De Montfort Univ., Leicester, UK, 2013.
23. [20] U. Tanrikulu, E. Akboy, and B. Akin, “Design and Analysis of a Flyback Converter With Improved Snubber Cells,” Sigma J. Eng. Nat. Sci., vol. 38, no. 4, pp. 2205–2216, 2020.
24. [21] E. Kabalci and A. Boyar, “Design and Analysis of a Single Phase Flyback Micro Inverter,” in 2018 6th International Conference on Control Engineering & Information Technology (CEIT), Oct. 2018, pp. 1–6.
25. [22] E. Baldan and H. Erişti, “Parçalı Gölgelenme Durumunda Yapay Sinir Ağları ve Parçacık Sürü Optimizasyonu Tabanlı Bir Maksimum Güç Noktası Takibi Algoritması,” Kahramanmaraş Sütçü İmam Üniversitesi Mühendislik Bilim. Derg., vol. 26, no. 4, pp. 895–908, Dec. 2023.
26. [23] K. A. El Wahid Hamza, H. Linda, and L. Cherif, “LCL filter design with passive damping for photovoltaic grid connected systems,” in IREC2015 The Sixth International Renewable Energy Congress, Mar. 2015, pp. 1–4.
27. [24] A. E. W. H. Kahlane, L. Hassaine, and M. Kherchi, “LCL filter design for photovoltaic grid connected systems,” Third Int. Semin. new Renew. energies, vol. 8, no. 2, pp. 227–232, 2014.