ABSTRACT
This
paper presents the simulation studies on a Cascaded H-Bridge converter based Distribution
Static Synchronous Compensator (DSTATCOM) for improving the power quality of a
distribution system. Voltage source converter based DSTATCOM has been
established as the most preferred solution for management of reactive power in
distribution utilities and for improving voltage regulation, power factor and power
quality in industries. For high power applications, cascaded H-Bridge converter
is the most ideal choice compared to two-level inverter with series connected
power devices. In the present work DSTATCOM controller is designed using DQO modelling
for reactive power management and thereby improving the power factor in
distribution systems. The dc link voltage and the three phase load currents are
used as feedback signals for the controller and it is designed in such a way
that DSTATCOM is able to supply the reactive current demanded by the load both
during steady state and transient conditions using sinusoidal pulse width
modulation control.
KEYWORDS
1. Cascaded
H-Bridge Converter
2. DSTATCOM
3. Reactive
power compensation
4. Sinusoidal PWM
SOFTWARE:
MATLAB/SIMULINK
SIMULINK BLOCK DIAGRAM:
Fig.
1. The cascade H-bridge converter based DSTATCOM.
EXPECTED SIMULATION RESULTS
Fig.
2. The phase voltage (top trace ) and line-to-line voltages of H-bridge
cascaded
inverter.
Fig.
3. Source phase voltage (top trace) and source phase Current (bottom
trace)
with DSTATCOM in closed loop power factor control mode.
Fig.
4. DC link voltage (Vd,) (Top or First Trace), direct and quadrature axis
source
currents (Second Trace) ,inverter currents Id and Iq (Third Trace) and
load
reactive current (Bottom Trace).
Fig 5.
Individual Capacitor voltages of three level Cascaded H-Bridge
Inverter.
CONCLUSION
The
paper presents the principle of operation of cascaded H-bridge converter and
simulation studies on cascaded converter based DSTATCOM using Sinusoidal PWM
control. It is observed that the DSTATCOM is capable of supplying the reactive
power demanded by the load both during steady state and transient operating
conditions. The harmonics in cascaded H-bridge three-level inverter current are
less compared to two-level inverter operating at same switching frequency.
REFERENCES
[1]
Jih-Sheng Lal, Fang Zheng Peng," Multilevel Converters - A New Breed of
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[2]
Muni B.P., Rao S.E., Vithal J.V.R., Saxena S.N., Lakshminarayana S., Das R.L.,
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Applications", Conference Proceedings, IEEE, Region Tenth Annual
Conference, TENCON-03. Page(s): 278- 282 Vol. 1
[3]
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