Einstein International Journal Organization(EIJO)

Abstract  

This paper proposes a new Nine Level Inverter for a photovoltaic system. The nine- level inverter is configured using a capacitor selection circuit and a full-bridge power converter, connected in cascade. Since the output of PV array is very low, a DC –DC converter is used to boost the output of PV array. The DC-DC power converter consists of DC-DC boost converter and a transformer to convert the output voltage of the PV array into three independent voltage sources with multiple relationships.

The capacitor selection circuit in the nine-level inverter converts the three output voltage sources of DC–DC power converter into a four-level DC voltage, and the full-bridge power converter further converts this four-level DC voltage into a nine-level AC voltage. In this way, the proposed system can generates a sinusoidal output current that is in phase with the utility voltage and is fed into the utility. The salient features of the proposed nine-level inverter are that only seven power electronic switches are used. The proposed concepts have been verified by MATLAB simulations.

Keywords: Distribution System, Multilevel inverter.

[1] R. Dugan, T. McDermott, “Distributed generation,” IEEE Ind. Appl. Mag., vol. 8, no. 2, pp. 19-25, Mar./Apr. 2002.

[2] R. A. Mastromauro, M. Liserre, and A. Dell’Aquila, “Control issues in single-stage photovoltaic systems: MPPT, current and voltage control,” IEEE Trans. Ind. Informat., vol. 8, no. 2, pp. 241–254, May. 2012.

[3] N. Mohan, T. M. Undeland, and W. P. Robbins, “Power Electronics Converters, Applications and Design”, Media Enhanced 3rded. New York,NY, USA: Wiley, 2003.

.[4] J.-M. Shen, H. L. Jou, and J. C. Wu, “Novel transformer-less grid connected power converter with negative grounding for photovoltaic generation system,” IEEE Trans. Power Electron., vol. 27, no. 4, pp. 1818– 1829, Apr. 2012.

[5] Jinn-Chang Wu, Member, IEEE, and Chia-Wei Chou,” A Solar Power Generation System With a Seven-Level Inverter”, IEEE Trans. on power electronics, vol. 29, no. 7, july 2014

[6] K. Hasegawa and H. Akagi, “Low-modulation-index operation of a five level diode-clamped pwm inverter with a dc-voltagebalancing circuit for a motor drive,” IEEE Trans. Power Electron., vol. 27, no. 8, pp. 3495–3505, Aug. 2012.

[7] E. Pouresmaeil, D. Montesinos-Miracle, and O. Gomis- Bellmunt, “Control scheme of three-level NPC inverter for integration of renewable energy resources into AC grid,” IEEE Syst. J., vol. 6, no. 2, pp. 242–253, Jun. 2012.

[8] S. Srikanthan and M. K. Mishra, “DC capacitor voltage equalization in neutral clamped inverters for DSTATCOM application,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2768–2775, Aug. 2010

[9] N. A. Rahim, K. Chaniago, and J. Selvaraj, “Singlephase seven-level grid-connected inverter for photovoltaic system,” IEEE Trans. Ind. Electr.,vol. 58, no. 6, pp. 2435– 2443, Jun. 2011.

[10] S. Thielemans, A. Ruderman, B. Reznikov, and J. Melkebeek, “Improved natural balancing with modified phase-shifted PWM for single-leg fivelevel flying-capacitor converters,” IEEE Trans. Power Electron., vol. 27, no. 4, pp. 1658–1667, Apr. 2012.

[11] S. Choi and M. Saeedifard, “Capacitor voltage balancing of flying capacitor multilevel converters by space vector PWM,” IEEE Trans. Power Delivery, vol. 27, no. 3, pp. 1154 1161, Jul. 2012.

[12] L. Maharjan, T. Yamagishi, and H. Akagi, “Activepower control of individual converter cells for a battery energy storage system based on a multilevel cascade pwm converter,” IEEE Trans. Power Electron., vol. 27, no. 3, pp. 1099– 1107, Mar. 2012.

[13] A. J.Watson, P.W. Wheeler, and J. C. Clare, “A complete harmonic eliminationapproach to DC link voltage- balancing for cascaded multilevelrectifier,” IEEE Trans. Ind. Electron., vol. 54, no. 6, pp. 2946–2953, Dec.2007

[14] S. Sirisukprasert, A. Q. Huang, and J. S. Lai, “Modeling, analysis and controlof cascaded-multilevel converter-based STATCOM,” in Proc. IEEEPower Eng. Soc., 2003, pp. 2561–2568.

[15] T. Esram and P. L. Chapman, “Comparison of photovoltaic array maximumpower point tracking techniques,” IEEE Trans. Energy Convers.,vol. 22, no. 2, pp. 439–449, Jun. 2007.

[16] D. Floricau, E. Floricau, and G. Gateau, “New multilevel converters withcoupled inductors: Properties and control,” IEEE Trans. Ind. Electron.,vol. 58, no. 12, pp. 5344–5351, Dec. 2011.