Selective Harmonic Elimination in Multi-level Inverters with Series-Connected Transformers with Equal Power Ratings

  • Moussa, Mona Fouad ;
  • Dessouky, Yasser Gaber
  • Received : 2015.06.09
  • Accepted : 2015.10.01
  • Published : 2016.03.20


This study applies the selective harmonic elimination (SHE) technique to design and operate a regulated AC/DC/AC power supply suitable for maritime military applications and underground trains. The input is a single 50/60 Hz AC voltage, and the output is a 400 Hz regulated voltage. The switching angles for a multi-level inverter and transformer turns ratio are determined to operate with special connected transformers with equal power ratings and produce an almost sinusoidal current. As a result of its capability of directly controlling harmonics, the SHE technique is applicable to apparatus with congenital immunity to specific harmonics, such as series-connected transformers, which are specially designed to equally share the total load power. In the present work, a single-phase 50/60 Hz input source is rectified via a semi-controlled bridge rectifier to control DC voltage levels and thereby regulate the output load voltage at a constant level. The DC-rectified voltage then supplies six single-phase quazi-square H-bridge inverters, each of which supplies the primary of a single-phase transformer. The secondaries of the six transformers are connected in series. Through off-line calculation, the switching angles of the six inverters and the turns ratios of the six transformers are designed to ensure equal power distribution for the transformers. The SHE technique is also employed to eliminate the higher-order harmonics of the output voltage. A digital implementation is carried out to determine the switching angles. Theoretical results are demonstrated, and a scaled-down experimental 600 VA prototype is built to verify the validity of the proposed system.


AC to DC converter;DC to AC inverters;Power supply;Regulated power supply


  1. A. M. Ruban, N. Hemavathi, and N. Rajeswari, "Real time harmonic elimination PWM control for voltage source inverters," in Conf. Rec. Advances in Engineering, Science and Management (ICAESM), pp. 479-484, 2012.
  2. Y. Zhang and X. Ruan, “AC-AC Converter with Controllable Phase and Amplitude,” IEEE Trans. PowerElectron., Vol. 29, No. 11, pp. 6235-6244, Jan. 2014.
  3. A. K. Al Othman, N. A. Ahmed, M. E. Alsharidah, and H. A. Al Mekhaizim, “A hybrid real coded genetic algorithm – pattern search approach for selective harmonic elimination of PWM AC/AC voltage controller,” Electrical Power and Energy Systems, Vol. 44, No. 1, pp. 123-133, Jan. 2013.
  4. J. L. Díaz Rodriguez, L. D. F. Pabon, and A. Pardo Garcia, "Harmonic distortion optimization of multilevel PWM inverter using genetic algorithms," in Conf. Rec. IEEE 5th Colombian Workshop on Circuits and Systems (CWCAS), pp. 1-6, 2014.
  5. M. Balasubramonian and S. Dharani, "Design and implementation of SHE PWM in a single phase A.C. chopper using generalized hopfield neural network," in Conf. Rec. Engineering Technology and Science- (ICETS'14), pp. 2347-6710, 2014.
  6. H. Lou, C. Mao, D. Wang, J. Lu, and L. Wang, “Fundamental modulation strategy with selective harmonic elimination for multilevel inverters,” IET Power Electronics, Vol. 7, No. 8, pp. 2173-2181, Aug. 2014.
  7. S. Kouro, M. Malinowski, K. Gopakumar, J. Pou, L.G. Franquelo, W. Bin, J. Rodriguez, M.A. Perez, and J.I. Leon, “Recent advances and industrial applications of multilevel converters,” IEEE Trans. Ind. Electron., Vol. 57, No. 8, pp. 2553-2580, Aug. 2010.
  8. W. Fei, B.Wu, and Y. Huang, “Half-wave symmetry selective harmonic elimination method for multilevel voltage source inverters,” IEE Proc. Power Electron., Vol. 4, No. 3, pp. 342-351, 2011.
  9. G. S. Konstantinou, M. S. A. Dahidah, and V. G. Agelidis, “Solution trajectories for selective harmonic elimination pulse-width modulation for seven-level waveforms: analysis and implementation,” IEE Power Electron., Vol. 5, No. 1, pp. 22-30, Mar. 2012.
  10. F. Wanmin, D. Xiaoli, and W. Bin, “A generalized halfwave symmetry SHE-PWM formulation for multilevel voltage inverters,” IEEE Trans. Ind. Electron., Vol. 57, No. 9, pp. 3030-3038, Apr. 2010.
  11. M. S. A. Dahidah and V. G. Agelidis, “Selective harmonic elimination PWM control for cascaded multilevel voltage source converters: A generalized formula,” IEEE Trans. Power Electron., Vol. 23, No. 4, pp. 1620-1630, May 2008.
  12. S. Bhadra and H. Patangia, "A microcontroller based SHE inverter for maximum power point operation," in Conf. IEEE PEDS, Australia 9 - 12 June 2015.
  13. D. Ahmadi and J. Wang, “Online selective harmonic compensation and power generation with distributed energy resources,” IEEE Trans. Power Electron., Vol. 29, No. 7, pp. 3738-3747, Jul. 2014.
  14. V. G. Agelidis, A. I. Balouktsis, and C. Cossar, “On attaining the multiple solutions of selective harmonic elimination PWM three-level waveforms through function minimization,” IEEE Trans. Ind. Electron., Vol. 55, No. 3, pp. 996-1004, Mar. 2008.
  15. M. T. Hagh, H. Taghizadeh, and K. Razi, “Harmonic minimization in multilevel inverters using modified speciesbased particle swarm optimization,” IEEE Trans. Power Electron., Vol. 24, No. 10, pp. 2259-2267, Oct. 2009.
  16. D.A. Paice, Power Electronic Converter Harmonics: Multi-Pulse Methods for Clean Power, New York: IEEE Press, 1996.
  17. H. Taghizadeh and M.T. Hagh, “Harmonic elimination of cascade multilevel inverters with nonequal DC sources using particle swarm optimization,” IEEE Trans. Ind. Electron., Vol. 57, No. 11, pp. 3678-3684, Jul. 2010.
  18. D. Roy and T. Roy "A new technique to implement conventional as well as advanced pulse width modulation techniques for multi-level inverter," Power Electronics (IICPE), 2014 IEEE 6th India International Conference on 2014.
  19. A. Lhaligh, J. R. Wells, P. L. Chapman, and P.T. Krein, “Dead-time distortion in generalized selective harmonic control,” IEEE Trans. Power Electron., Vol. 23, No. 3, pp. 1511-1517, 2008.
  20. M.F. Moussa, N. Biomy, and Y.G. Dessouky, "Stabilized power AC-DC-AC converter using polygon transformer," in Conf. Rec. Renewable Energies and Power Quality (ICREPQ'11)', 2011.
  21. M.F. Moussa, H. Hussein, and Y.G. Dessouky, "Regulated AC/DC/AC Power Supply Using Scott Transformer," in Conf. Rec. IET, (PEMD), 2012.
  22. M. F. Moussa and Y. G. Dessouky, "Design and control of a diode clamped multilevel wind energy system using a standalone AC-DC-AC converter," in Conf. Rec. Sustainability in Energy and Buildings conference SEB'12, 2012.
  23. M. F. Moussa and Y. G. Dessouky, “Selective harmonic control for AC-DC-AC regulated converter AC-DC-AC converter,” International Journal of Advanced Renewable Energy Research (IJARER), Vol. 1, No. 8, pp. 481-486, Oct. 2012.
  24. S. N. Rao, D. V. A. Kumar, and C. S. Babu, "New multilevel inverter topology with reduced number of switches using advanced modulation strategies," in Conf. Rec. Power, Energy and Control (ICPEC), pp. 693-699, 2013.
  25. Law Kah Haw, Mohamed S. A. Dahidah, and Haider A. F. Almurib, “SHE–PWM cascaded multilevel inverter with adjustable DC voltage levels control for STATCOM applications,” IEEE Trans. Power Electron., Vol. 29, No. 12, pp. 6433-6444, Dec. 2014.
  26. C. M. Young, S. F. Wu, and Y.Z. Liu, "Implementation of a multi-level inverter based on selective harmonic elimination and zig-zag connected transformers," in Conf. Rec. Power Electronics Drive Syst., pp. 387-392, 2009.
  27. M. Murugan and P. Balaraman, "Selective harmonic elimination PWM method in two level inverter by differential evolution optimization technique," in Conf. IEEE on Recent Advances and Innovations in Engineering (JCRAIE-2014), 2014.
  28. R. Singuor, P. Solanki, N. Pathak and D. S. Babu, “Simulation of single phase transformer with different supplies,” International Journal of Scientific and Research Publications, Vol. 2, No. 4, Apr. 2012.