The
goal of this paper is to investigate the application of nonlinear control technique
to a multi-input multi output (MIMO) nonlinear model of a wind energy battery storage
system using a permanent magnet synchronous generator (PMSG). The challenge is
that the system should operate in both grid-connected and standalone modes
while ensuring a seamless transition between the two modes and an efficient
power distribution between the load, the battery and the grid. Our approach is
different from the conventional methods found in literature, which use a
different controller for each of the modes. Instead, in this work, a single
unified nonlinear controller is proposed. The proposed control system is
evaluated in simulation. The results showed that the proposed control scheme
gives high dynamic responses in response to grid power outage and load variation
as well as zero steady-state error.
KEYWORDS:
1. Battery
storage
2. Bi-directional
buck-boost converter
3. Feedback
linearization
4. Grid-connected
5. Multi-input
mutioutput
6. Permanent
magnet synchronous generator
7. Stand-alone
8. Wind
turbine
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1. WECS based permanent magnet synchronous generator.
Fig.
2. Optimum Rotor Speed and Output Power.
Fig.
3. Voltage and current of the load.
Fig.
4. dc-link voltage.
Fig.
5. Wind Turbine Output Power (MW).
Fig.
6. Load Power (MW).
Fig.
7. Charge/discharge of Battery (%).
Fig.
8. Grid Power (MW).
CONCLUSION:
This
paper has proposed a nonlinear MIMO controller based on the feedback
linearization theory to regulate the load voltage in both grid-connected and
stand-alone mode while ensuring a seamless transition between the two modes and
an efficient power distribution between the load, the battery and the grid. Our
approach is different from the conventional methods found in literature, which
use a different controller, PID based, for each mode of operation. Instead, in
this work, a single unified nonlinear controller is proposed. The performance
of the proposed controller has been tested with different wind speeds as well
as in the two modes of operation with dynamic load. The simulation results show
that applying nonlinear feedback linearization based control strategy provides
a good control performance. This performance is characterized by fast and
smooth transient response as well as good steady state stability and reference
tracking quality, even with variable wind speed and dynamic load operation. However,
this study assume that the system parameters are fixed. A future work will be
to test the system when parameters are unknown using adaptive control design
theory.
REFERENCES:
[1]
M. Fatu, F. Blaabjerg, and I. Boldea, “Grid to standalone transition motion-sensorless
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3463–3472, Jul. 2014.
[2]
M. Fatu, L. Tutelea, R. Teodorescu, F. Blaabjerg, and I. Boldea, “Motion sensorless
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PESC 2007. IEEE. IEEE, 2007, pp. 1239–1244.
[3]
R. Teodorescu and F. Blaabjerg, “Flexible control of small wind turbines with
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Transactions on Power Electronics, vol. 19, no. 5, pp. 1323–1332, Sept.
2004.
[4]
T. Chaiyatham and I. Ngamroo, “Optimal fuzzy gain scheduling of pid controller
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[5]
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