A control strategy of DC-link voltages for a seven-level cascaded H-bridge inverter is proposed in this paper. The DC-link voltage balancing is accomplished by an appropriate selection of H-bridges and control of their duty cycles in space-vector modulation (SVM) algorithm. The proposed SVM method allows to maintain the same voltage level on all inverter capacitors. Regardless of the balancing function, the SVM strategy makes it possible to generate the output voltage vector properly also in the case where the DC-link voltages are not balanced. The results of simulation and experimental investigations are presented in the paper.
 J. Rodriguez, J. Pontt, E. Silva, J. Espinoza, and M. Perez, “Topologies for regenerative cascaded multilevel inverters,” in Proc. 34th Annu. Power Electron. Spec. Conf. IEEE PESC 2, 519–524 (2003).
 M.R. Islam, Y. Guo, and J. Zhu, “A high-frequency link multilevel cascaded medium-voltage converter for direct grid integration of renewable energy systems,” IEEE Trans. Power Electron. 29 (8), 4167–4182, (2014).
 J. Rodriguez et al., “High-voltage multilevel converter with regeneration capability,” IEEE Trans. Ind. Electron. 49 (4), 839–846, (2002).
 A. Goodman, A. Watson, A. Dey, J. Clare, P. Wheeler, and Y. Zushi, “DC side ripple cancellation in a cascaded multi-level topology for automotive applications,” in Proc. IEEE ECCE, 5916–5922 (2014).
 H. Vahedi, K. Al-Haddad, P.-A. Labbe, and S. Rahmani, “Cascaded multilevel inverter with multicarrier PWM technique and voltage balancing feature,” in Proc. 23rd Int. Symp. Ind. Electron. IEEE ISIE, 2155–2160 (2014).
 A. Kumar, D. Kumar, and D. R. Meena, “SRF based modeling and control of cascaded multilevel active rectifier with uniform DC-buses,” in Proc. Recent Adv. Eng. Comp. Scien. RAECS, 1–5 (2014).
 A. Marzoughi, H. Imaneini, “Optimal selective harmonic elimination for cascaded H-bridge-based multilevel rectifiers,” IET Power Electron. 7 (2), 350–356, (2014).
 O.A. Taha, M. Pacas, “Hardware implementation of balance control for three-phase grid connection 5-level cascaded H-bridge converter using DSP,” in Proc. 23rd Int. Symp. Ind. Electron. IEEE ISIE, 1366–1371 (2014).
 I. Ahmed and V. B. Borghate, “Simplified space vector modulation technique for seven-level cascaded H-bridge inverter,” IET Power Electron. 7 (3), 604–613 (2014).
 P.I. Correa Vasquez, Fault Tolerant Operation of Series Connected H-Bridge Multilevel Inverters, 2006.
 J. Gholinezhad and R. Noroozian, “Application of cascaded H-bridge multilevel inverter in DTC-SVM based induction motor drive,” in Proc. 3rd Power Electron. Drive Sys. Techn. PEDSTC, 127–132 (2012).
 E.P. Nowicki and B.N. Roodsari, “Fast space vector modulation algorithm for multilevel inverters and its extension for operation of the cascaded H-bridge inverter with non-constant DC sources,” IET Power Electron. 6 (7), 1288–1298 (2013).
 A. Marzoughi, Y. Neyshabouri, and H. Imaneini, “Control scheme for cascaded H-bridge converter-based distribution network static compensator,” IET Power Electron. 7 (11), 2837–2845 (2014).
 Y. Sun, J. Zhao, and Z. Ji, “An improved CPS-PWM method for cascaded multilevel STATCOM under unequal losses,” in Proc. 39th Annu. Conf. IEEE IECON, 418–423 (2013).
 J. Chavarria, D. Biel, F. Guinjoan, C. Meza, and J. J. Negroni, “Energy-balance control of PV cascaded multilevel grid-connected inverters under level-shifted and phase-shifted PWMs,” IEEE Trans. Ind. Electron. 60 (1_, 98–111 (2013).
 M. Angulo, P. Lezana, S. Kouro, J. Rodriguez, and B. Wu, “Level-shifted PWM for cascaded multilevel inverters with even power distribution,” in Proc. Power Electron. Spec. Conf. IEEE PESC, 2373–2378 (2007).
 C. Gu, Z. Zheng, Y. Li, “A novel voltage balancing method of cascaded H-bridge rectifiers for locomotive traction applications,” in Proc. 15th Europ. Conf. Power Electron. A EPE, 1–8 (2013).
 M. Moosavi, G. Farivar, H. Iman-Eini, S.M. Shekarabi, “A voltage balancing strategy with extended operating region for cascaded H-bridge converters,” IEEE Trans. Power Electron. 29 (9), 5044–5053 (2014).