ABSTRACT:
In this paper a model predictive control (MPC) has been
designed and implemented on the Packed U-Cell (PUC) inverter which has one
isolated DC source and one capacitor as an auxiliary DC link. The MPC is
designed to regulate the capacitor voltage at the desired magnitude to have
seven voltage levels at the output of the inverter. Since grid-connected application
is targeted by this application, the inverter should be capable of supplying
requested amount of active and reactive power at the point of common coupling
(PCC) as well. Therefore, MPC should also consider the line current control in
order to monitor the exchange of reactive power with the grid while injecting
appropriate active power at low THD. Various experimental tests including
change in DC source voltage, active power variation and operation at different
power factor (PF) have been performed on a laboratory prototype to validate the
good performance obtained by the proposed MPC. The dynamic performance of the
controller during sudden changes in dc capacitor voltage, supply current and PF
demonstrates the fast and accurate response and the superior operation of the
proposed controller.
KEYWORDS:
1.
PUC Inverter
2.
Multilevel
Inverter
3.
Model
Predictive Control
4.
Grid-Connected
PV
5.
Power Quality
SOFTWARE:
MATLAB/SIMULINK
CONCLUSION:
In
this paper, a Model Predictive Control has been designed for the 7-level PUC
inverter in grid-connected mode of operation, an excellent candidate for
photovoltaic and utility interface application to deliver green power to the
utility. MPC is a simple and intuitive method that does not have confusing gains
to adjust as well as featuring fast response during any change in the system
parameters. Experimental results have been provided to show the fast response
of the implemented controller on the grid-connected multilevel PUC inverter. It
has been demonstrated that the DC link capacitor voltage has been regulated at
desired level and 7-level voltage waveform has been generated at the output of
the inverter. The injected current to the grid was successfully controlled to
have regulated amplitude and synchronized waveform with the grid voltage to
deliver maximum power with unity power factor. Moreover, the PF has been
controlled easily to exchange reactive power with the grid while injecting the
available active power. Exhaustive experimental results including change in the
grid current reference, DC source and AC grid voltages variations, as well as
PF have been tested and results have been illustrated which ensured the good
dynamic performance of the proposed controller applied on the gridconnected PUC
inverter.
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