ABSTRACT

Multilevel voltage-fed inverters with space vector pulse width modulation method are gained importance in high power high work industrial drive use. This paper planned a new simplified space vector PWM method for a three-level inverter fed induction motor drive.

PWM

The three- level inverter has a large number of switching states compared to a two-level inverter.In the planned scheme, three-level space vector PWM inverter is easily achieve as conventional two-level space vector PWM inverter. Therefore, the planned method can also be applied to multilevel inverters.

R-L LOAD

In this work, a three-level inverter using space vector modulation method has been modeled and simulated.Simulation results are given for various operation conditions using R-L load and motor load to verify the system model.

KEYWORDS

1. Space vector PWM
2. Three-level inverters
3. Multilevel inverters

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig.1 Three level multilevel inverter using cascaded inverters with separated DC sources

EXPECTED SIMULATION RESULTS

Fig.2 The line output voltage waveform for fo=10Hz and m=0.65

Fig.3 Three-phase line output current waveforms for fo=10Hz and m=0.65

Fig.4 The line output voltage waveform and its spectrum for fo=10Hz and m=0.65.

Fig.5 The line output voltage waveform for fo=50Hz and m=0.7

CONCLUSION

The space vector PWM algorithm for a three level voltage-fed inverter using cascaded H-bridges inverter has been modeled and simulated using Simulink/MATLAB package program. Simulation results have been given for both R-L and induction motor loads using 1 kHz switching density with various output density.

MULTILEVEL INVERTER

The planned control algorithm used in the three-level inverter can be easily applied to multilevel inverters with more than three levels. It has been shown that high quality waveforms at the output of the multilevel inverter can be get even with 1 kHz of low switching density.

REFERENCES

1. M. Bhagwat and V.R. Stefanovic, “Generalized Structure of A Multilevel Inverter”, IEEE Trans. On I.A., Vol. IA-19, n.6, 1983, pp. 1057-1069.
2. K. Mondal, J.O.P Pinto, B.K. Bose, “A Neural- Network-Based Space Vector PWM Controller for a Three-Level Voltage-Fed Inverter Induction Motor Drive”, IEEE Trans. on I.A., Vol. 38, no. 3, May/June 2002, pp.660-669.
3. K. Mondal, B.K. Bose, V. Oleschuk and J.O.P Pinto, “Space Vector Pulse Width Modulation of Three-Level Inverter Extending Operation Into Overmodulation Region”, IEEE Trans. on Power Electronics, Vol. 18, no. 2, March 2003, pp.604-611.
4. Manjrekar and G. Venkataramanan, “Advanced Topologies and Modulation Strategies for Multilevel Inverters”, Power Electronics Specialists Conference, Vol. 2, 23-27 June 1996, pp. 1013-1018.
5. Nabae, I. Takahashi and H. Akagi, “A New Neutral-Point-Clamped PWM Inverter”, IEEE Trans. on I.A., Vol. 17, No.5, September/October 1981, pp.518-523.