An Efficient Grid-tied Flyback Micro-inverter with DCM Control Strategy

  • Salam Jabr Yaqoob Authority of the Popular Crowed, Prime Minister, Iraq
  • Adel A. Obed Electrical Engineering Technical College, Middle Technical University, Iraq
Keywords: Single-stage micro-inverter, Grid-tied Micro-inverter, flyback inverter, DCM control strategy, SPWM control, PSIM simulation


In two-stage micro-inverter photovoltaic (PV) applications, DC/DC converter is used to obtain the highest DC power from the PV module. In this type of inverter, the rising of voltage from the PV module to a grid voltage level is limited to a certain value. Moreover, the absence of the isolation between the input and output makes it is less efficient. For these reasons, an efficient single-stage grid-tied flyback PV micro-inverter with discontinuous conduction mode (DCM) control strategy is proposed to feed an alternating current (AC) to the main grid with a lower value of the total harmonic distortion (THD). The control strategy is based on a sine sinusoidal pulse width modulation (SPWM) technique to control the main switch of flyback inverter. Also, a simple perturb and observe (P&O) maximum power point tracking (MPPT) technique has been presented to obtain the MPP point from the PV module for any environmental conditions. The proposed control was verified using PSIM software and simulation results is obtained. The proposed control is tested under different weather conditions for solar irradiance and temperature, as a result, a pure sin wave current has been injected into the grid with a lower harmonics value. Finally, the small size, low cost and high reliability of single stage flyback micro-inverter is presented without the need for DC/DC converter.


G. Eason, B. Noble, and I. N. Sneddon, “On certain integrals of Lipschitz-Hankel type involving products of Bessel functions,” Phil. Trans. Roy. Soc. London, vol. A247, pp. 529–551, April 195.

A. Khaligh and O. Oner, “Energy Harvesting Solar, Wind, and Ocean Energy Conversion Systems,” Talyer and Franceis Group, ISBN: 978-1-4398-1508-3, U.S.A, 2010.

Yaqoob, S. J., & Obed, A. A. (2019). Modeling, Simulation and Implementation of PV System by Proteus Based on Two-diode Model. Journal of Techniques, 1(1), 39-51.‏

Mohammadi, S., Izadfar, H. R., & Eskandarian, N. (2020). Performance optimisation of the grid-connected flyback inverter under improved hybrid conduction mode. IET Renewable Power Generation, 14(13), 2437-2446.‏

M. Dong, X. Tian, L. Li, D. Song, L. Wang, and M. Zhao, “Model –Based Current Sharing Approach for DCM Interleaved Flyback Micro-inverter,” Energies, Vol. 11, No. 7, pp.1685, Jul. 2018.

A. Ch. Kyristis, E. C. Tatakis, and N.P. Papanikolaou, “Optimum Design of the Current-Source Flyback Inverter for Decentralized Grid-connected Photovoltaic Systems,” IEEE Transactions on Energy Conversion, Vol.23, No.1, pp.281-293, Mar. 2008.

Y. Kim, J. Kim, Y. Ji, C. Won, and T. Lee, “Flyback Inverter Using Voltage Sensor-less MPPT for AC Module Systems,” IEEE Power Electronics Conference (IPEC), pp.948-953, Jun. 2010.

Y. Kim, J. Kim, Y. Ji, C. Won, and T. Lee, “A New Control Strategy of Active Clamped Flyback Inverter for A Photovoltaic AC Module System,” IEEE, 8th International Conference on Power Electronics Conference (ECCE), pp.1880-1885, Korea, May 30 - June 3, 2011.

J. Jan, Y. Kim, D. Ryu, C. Won, and Y. Jung, “High Efficiency Control Method for Interleaved Flyback Inverter with Synchronous Rectifier Based on Photovoltaic AC Modules,” IEEE, 38th Annual Conference in Industrial Electronics Society (IECON), pp.5720-5725, Oct. 2012.

S. Öztürk and I. Çadirci, “DSPIC Microcontroller Based Implementation of A Flyback PV Micro-Inverter Using Direct Digital Synthesis,” IEEE Energy Conversion Congress and Exposition (ECCE), pp. 3426 - 3433, Denver, Sep. (15-19), 2013.

Salam J. Yqoob, A. A. Obed, “Photovoltaic Flybck Micro-inverter with Power Decoupling Technique,” Indonesian Journal of Electrical Engineering and Computer Science (IJEECS) vol.15 no.1 pp. 9-19 July, 2019.

B. D. Reddy, M. P. Selvan and S. Moorthi, “Design, Operation, and Control of S3 Inverter for Single-Phase Micro-grid Applications,” IEEE Transactions on Industrial Electronics, Vol. 62, No. 9, pp. 5569–5577, Sep. 2015.

H. A.Sher, K. E. Addoweesh and K. Al-Haddad, “Performance Enhancement of a Flyback Photovoltaic Inverter using Hybrid Maximum Power Point Tracking,” IEEE, 1st Annual Conference in Industrial Electronics Society (IECON), pp. 005369 - 005373, Yokohama, Nov. (9-12). 2015.

M. Khalilian, M. M. Rad, E. Adib, and H. Farzanehfard,“New Single-Stage Soft Switching Flyback Inverter for AC Module Application with Simple Circuit,” IEEE, 6th International Power Electronics Drive Systems and Technologies Conference (PEDSTC), pp. 41-46, 3-4 February, Tehran, Iran. 2015.

J.Liao, J. Su, L. Chang, and J. Lai, “A Mixed Decoupling Power Method for Single-Phase Grid-connected Inverters,” IEEE, 7th international Symposium on Power Electronics for Distributed Generator Systems (PEDG) pp.1-5, Jun. 2016.

T. Lodh, and V. Agarwal, “Single Stage Multi-Port Flyback Type Solar PV Module Integrated Micro-inverter with Battery Backup,” IEEE, International Conference in Power Electronics, Drives, and Energy Systems (PEDES), pp.1-6, Dec.2016.

M. Kalilian, and P. Guglilmi, “Single Stage Grid-connected Flyback Inverter with Zero Current Switching for AC Module Application,” IEE, Annual Conference in Industrial Electronics Society (IECON), pp.2390-2395, Oct.2016.

C. L. Trujillo, F.Santamaria, and E. E. Gaona, “Modeling and Testing of Two-Stage Grid-connected Photovoltaic Micro-inverter,” Elsevier publisher, Renewable Energy, Vol.99, pp.533-542, Jul.2016.

S. Sukatjasakul and S. Po-Ngam “The Micro-grid Connected Single-Phase Photovoltaic Inverter with Simple MPPT Controller,” IEEE, 5th International Electrical Engineering Congress, Pattaya, Thailand, pp.1-4, Mar. (8-10), 2017.

Saleh, A. L., Obed, A. A., Hassoun, Z. A., & Yaqoob, S. J. (2020, July). Modeling and Simulation of A Low Cost Perturb& Observe and Incremental Conductance MPPT Techniques In Proteus Software Based on Flyback Converter. In IOP Conference Series: Materials Science and Engineering (Vol. 881, No. 1, p. 012152). IOP Publishing.‏

Yaqoob, S. J., Hussein, A. R., & Saleh, A. L. (2020). Low Cost and Simple P&O-MPP Tracker Using Flyback Converter. Solid State Technology, 63(6), 9676-9689.‏

Ram, J. P., Babu, T. S., & Rajasekar, N. (2017). A comprehensive review on solar PV maximum power point tracking techniques. Renewable and Sustainable Energy Reviews, 67, 826-847.‏

Ram, J. P., & Rajasekar, N. (2016). A novel flower pollination based global maximum power point method for solar maximum power point tracking. IEEE Transactions on Power Electronics, 32(11), 8486-8499.‏

Bahrami, M., Gavagsaz-Ghoachani, R., Zandi, M., Phattanasak, M., Maranzanaa, G., Nahid-Mobarakeh, B., ... & Meibody-Tabar, F. (2019). Hybrid maximum power point tracking algorithm with improved dynamic performance. Renewable energy, 130, 982-991.‏

Fadhel, S., Diallo, D., Delpha, C., Migan, A., Bahri, I., Trabelsi, M., & Mimouni, M. F. (2020). Maximum power point analysis for partial shading detection and identification in photovoltaic systems. Energy Conversion and Management, 224, 113374.‏

Tavakoli, S., & Safaei, M. (2018). Analytical PID control design in time domain with performance-robustness trade-off. Electronics Letters, 54(13), 815-817.‏

How to Cite
Yaqoob, S., & Obed, A. (2021). An Efficient Grid-tied Flyback Micro-inverter with DCM Control Strategy. Journal of Techniques, 3(1), 74-84.