ABSTRACT:
This
paper presents an investigation of five-Level Cascaded H - bridge (CHB)
Inverter as Distribution Static Compensator (DSTATCOM) in Power System (PS) for
compensation of reactive power and harmonics. The advantages of CHB inverter
are low harmonic distortion, reduced number of switches and suppression of
switching losses. The DST ATCOM helps to improve the power factor and eliminate
the Total Harmonics Distortion (THD) drawn from a Non-Liner Diode Rectifier
Load (NLDRL). The D-Q reference frame theory is used to generate the reference
compensating currents for DSTATCOM while Proportional and Integral (PI) control
is used for capacitor dc voltage regulation. A CHB Inverter is considered for
shunt compensation of a 11 kV distribution system. Finally a level shifted PWM
(LSPWM) and phase shifted PWM (PSPWM) techniques are adopted to investigate the
performance of CHB Inverter. The results are obtained through Matlab/Simulink
software package.
KEYWORDS:
1. DSTATCOM
2. Level
shifted Pulse width modulation (LSPWM)
3. Phase
shifted Pulse width modulation (PSPWM)
4. Proportional-Integral (PI) control
5. CRB
multilevel inverter
6. D-Q reference frame theory
SOFTWARE: MATLAB/SIMULINK
SCHEMATIC DIAGRAM:
Fig.
1 Schematic Diagram of a DST ATCOM
Fig.
2 Block diagram of 5-level CHB inverter model
EXPECTED SIMULATION RESULTS:
Fig.
3 five level PSCPWM output
Fig.
4 Source voltage, current and load current without DSTATCOM
Fig. 5 DC Bus Vooltage
Fig.
6 Phase-A source voltage and current
Fig.
7 Harmonic spectrum of Phase-A Source current without DSTATCOM
Fig.
8 Harmonic spectrum of Phase-A Source current with DSTATCOM
CONCLUSION:
A
DSTATCOM with five level CHB inverter is investigated. Mathematical model for
single H-Bridge inverter is developed which can be extended to multi H Bridge. The
source voltage , load voltage , source current, load current, power factor
simulation results under nonlinear loads are presented. Finally Matlab/Simulink
based model is developed and simulation results are presented.
REFERENCES:
[
I ] K.A Corzine. and Y.L Familiant, "A New Cascaded Multi-level HBridge Drive:'
IEEE Trans. Power.Electron .• vol. I 7. no. I. pp. I 25-I 3 I . Jan 2002.
[2]
J.S.Lai. and F.Z.Peng "Multilevel converters - A new bread of converters,
"IEEE Trans. Ind.Appli .• vo1.32. no.3. pp.S09-S17. May/ Jun. 1996.
[3]
T.A.Maynard. M.Fadel and N.Aouda. "Modelling of multilevel converter:'
IEEE Trans. Ind.Electron .• vo1.44. pp.3S6-364. Jun. I 997.
[4]
P.Bhagwat. and V.R.Stefanovic. "Generalized structure of a multilevel PWM
Inverter:' IEEE Trans. Ind. Appln, VoI.IA-19. no.6, pp. I OS7-1069, Nov.!Dec ..
1983.
[5]
J.Rodriguez. Jih-sheng Lai, and F Zheng peng, "Multilevel Inverters; A
Survey of Topologies, Controls, and Applications," IEEE Trans. Ind.
Electron., vol.49 , n04., pp.724-738. Aug.2002.
