ABSTRACT:
This
work proposes a microgrid (μ-grid) integrating wind and solar photovoltaic (PV)
resources, along with the battery energy storage (BES) to the three phase grid
feeding the nonlinear load. The μ-grid disconcerted by probabilistic nonlinear
time dependent parameters and their effects are compensated by cohesive controllers
used for utility grid side voltage source converter (GVSC) and machine side VSC
(MVSC). The switching controls and the reconfigurability of the μ-grid are
addressed on imperative aspects of improving power quality (PQ), power
reliability, nonlinear load compensation and economic utilization of resources.
The nonlinear load compensation and PQ enhancement are achieved by executing
modified version of the adaptive filtering technique including “momentum” based
least mean square (MLMS) control technique, utilized for providing the
switching control signals to the GVSC. It utilizes two preceding gradient
weights for obtaining updated weight thereby improving the convergence rate and
overcoming the limitation of conventional control of the same family. The MVSC
acquires its switching signals from conventional vector control scheme and the
encoderless estimation of speed and rotor position of the synchronous generator
(SG) driven by wind turbine through back electromotive force control technique.
The external environmental disturbances are overcome by utilizing perturb and
observe (P&O) maximum power point (MPP) for wind optimal power extraction
and adaptive P&O with variable perturbation step size for solar MPP
estimation. Test results are obtained from the laboratory prototype under
steady state and dynamic conditions including altering wind speed, intermittent
solar insolation and variable load conditions. The PQ issues are addressed and
investigated successfully.
KEYWORDS:
1. Wind Power Generation
2. Solar PV Power Generation
3. AC Microgrid
4. MLMS
5. MPP and Power Quality
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
The
proposed wind-solar AC microgrid has been designed and implemented to
illustrate its improved PQ performance for local nonlinear load using MLMS adaptive
control. The weight component and system performance using MLMS has been found
with reduced oscillations. Effectiveness of the MLMS is realized through
successful harmonic elimination, extraction of load current fundamental
component with low static error and faster convergence rate. The wide range of
wind speeds, solar insolation and load variations have been considered and the
test results obtained from the prototype provide exceedingly well performance
for the entire operational range. The grid current THD has been found well
within the IEEE-519 harmonic standard. The proposed system has operated well
under all the dynamic conditions as well as the power quality issues are
mitigated satisfactorily.
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