Design and Implementation of a Novel Multilevel DC–AC Inverter

 ABSTRACT:

 In this paper, a novel multilevel dc–ac inverter is proposed. The proposed multilevel inverter generates seven-level ac output voltage with the appropriate gate signals’ design. Also, the low-pass filter is used to reduce the total harmonic distortion of the sinusoidal output voltage. The switching losses and the voltage stress of power devices can be reduced in the proposed multilevel inverter. The operating principles of the proposed inverter and the voltage balancing method of input capacitors are discussed. Finally, a laboratory prototype multilevel inverter with 400-V input voltage and output 220 Vrms/2 kW is implemented. The multilevel inverter is controlled with sinusoidal pulse-width modulation (SPWM) by TMS320LF2407 digital signal processor (DSP). Experimental results show that the maximum efficiency is 96.9% and the full load efficiency is 94.6%.

KEYWORDS:

1.      DC–AC inverter

2.      Digital signal processor (DSP)

3.      Maximum power point tracking (MPPT)

4.      Multilevel

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Block diagram of renewable system.

EXPECTED SIMULATION RESULTS:

Fig. 2. Waveforms of v_gs1, v_ab, v_o, and i_o at 500 W.

Fig. 3. Output voltage harmonic spectrum of v_ab calculated by FFT.

Fig. 4. Output voltage harmonic spectrum of v_o calculated by FFT

Fig. 5. Waveforms of vC2, v_o, and i_o at 1000 W.

Fig. 6. Waveforms of vC2, v_o, and i_o at 2000 W.

Fig. 7. Waveforms of v_o and i_o at 400 VA.

CONCLUSION:

A novel seven-level inverter was designed and implemented with DSP in this paper. The main idea of the proposed configuration is to reduce the number of power device. The reduction of power device is proved by comparing with traditional structures. Finally, a laboratory prototype of seven-level inverter with 400-V input voltage and output 220 Vrms/2kW is implemented. Experimental results show that the maximum efficiency is 96.9% and the full load efficiency is 94.6%.

REFERENCES:

[1] R. Gonzalez, E. Gubia, J. Lopez, and L. Marroyo, “Transformerless single-phase multilevel-based photovoltaic inverter,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2694–2702, Jul. 2008.

[2] S. Daher, J. Schmid, and F. L.M. Antunes, “Multilevel inverter topologies for stand-alone PV systems,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2703–2712, Jul. 2008.

[3] W. Yu, J. S. Lai, H. Qian, and C. Hutchens, “High-efficiency MOSFET inverter with H6-type configuration for photovoltaic nonisolated, acmodule applications,” IEEE Trans. Power Electron., vol. 26, no. 4, pp. 1253–1260, Apr. 2011.

[4] R. A. Ahmed, S. Mekhilef, and W. P. Hew, “New multilevel inverter topology with minimum number of switches,” in Proc. IEEE Region 10 Conf. (TENCON), 2010, pp. 1862–1867.

[5] M. R. Banaei and E. Salary, “New multilevel inverter with reduction of switches and gate driver,” in Proc. IEEE 18th Iran. Conf. Elect. Eng. (IECC), 2010, pp. 784–789.