ABSTRACT:
With the
increasing use of PV cells in power system, optimal utilization of the
equipment is an important issue. In these systems the MPPT controller is used
to inject the maximum available power from solar energy. During day time that
the active power decreases because of low intensity, the inverter is capable of
injecting reactive power up to its nominal capacity and this is a chance for reactive
power compensation. In this paper the aim is to propose a control method for
injecting the maximum active power and if possible, the reactive power. In addition,
a low pass filter is suggested to solve the problem of current fluctuations in
case of unbalanced load. Simulation results on a typical system in MATLAB
indicate proper performance of the presented method.
KEYWORDS:
1.
NPC inverter
2.
Maximum Power Point Tracking (MPPT)
3.
Photovoltaic cell (PV)
4.
PI current control
5.
Space vector pulse width modulation (SVPWM)
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig1.
Studied system for injecting power to the grid and local load
EXPECTED SIMULATION RESULTS:
Figure2. output active and reactive power of
the inverter
Figure3. THD of injected current to the
grid in no-load condition
Figure4. Injecting active power in no-load
condition and low intensity of light
Figure5. load increase at t=0.5s and its
effects on active and reactive power
Figure6. Injected voltage
and current to the grid and the effect of inductive load on current
Figure7. Analyzing THD of injected current to
the grid in PeL=50kw and PQL=30kvar condition
Figure8.
Power increment in two levels: a. at t=0.5s and b. at t=0.7s
Figure9. Output power of inverter and the
grid
Figure10. Output voltage and current after
using filter and limiter
Figure11. THD of circuit when PeL=50kw and
PQL=30kvar and using filter and limiter
CONCLUSION:
In this paper a control strategy is
proposed for current control of PV inverter that control s maximum generated
active power and reactive power compensation of local load simultaneously .The
main idea is to utilize inverter for reactive power injection during active
power decrement .using a low pass filter and power limiter in control system , produced
oscillations due to unbalanced load is eliminated and inverter works in safe
condition simulation results show the proposed method to be viable in
controlling inverter
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[1]
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ELECTRONICS, VOL. 28, NO. 4, APRIL 2013
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