ABSTRACT:
In
recent years, renewable energy sources, specifically solar power systems, have
developed rapidly owing to their technological maturity and cost effectiveness.
However, its grid integration deteriorates frequency stability because of
insufficient rotating masses and inertial response. Hence, a synchronverter,
which is an inverter that mimics the operation of a synchronous generator, is
crucial to interface solar power in a power grid. It stabilizes the power grid
by emulating a virtual inertia. However, a conventional proportional-integral(PI)-based synchronverter is not equipped with an adaptive damping factor (Dp)
or a digitalized smart controller to manage fast-responding solar inputs.
Hence, a novel fuzzy logic controller (FLC) framework is proposed such that the
synchronverter can operate in a grid-connected solar power system. In this
study, Dp is controlled in real time using an FLC to achieve balance between
speed and stability for frequency error correction based on frequency difference.
Results of four case studies performed in Matlab/Simulink show that the
proposed FLC-based synchronverter can stabilize the grid frequency by reducing
the frequency deviation by at least 0.2 Hz (0.4%), as compared with the
conventional PI-based synchronverter.
KEYWORDS:
1. Fuzzy logic controller (FLC)
2. Synchronverter
3. Renewable energy system (RES)
4. Grid stability
5. Solar power system
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1
Power section of synchronverter
EXPECTED SIMULATION RESULTS:
Fig. 2 Active power for varying resistive
loads (RL)
Fig. 3 Outputs of synchronverter for first
case study
Fig. 4 Testing environment for second case
study
Fig. 5 Outputs of synchronverter for second
case study
Fig. 6 Testing environment for third case
study
Fig. 7 Outputs of synchronverter for third
case study
Fig. 8 Testing environment for fourth case
study
Fig. 9 Outputs of synchronverter for fourth
case study
CONCLUSION:
Herein,
a novel FLC-based framework was proposed to control a synchronverter in a grid-
connected solar power system under dynamic weather conditions. Four case
studies were simulated in Matlab/Simulink, and the results validated the ability
of the proposed controller in stabilizing fg by reducing the frequency
deviation by at least 0.2 Hz (0.4%), as compared with the conventional PI-basedsynchronverter. The performance of the FLC-based synchronverter was optimal
even under sudden load changes or varying irradiances and temperatures. P was
injected or absorbed whenever the frequency decreased or increased,
respectively. The Dp controlled by the FLC was able to balance between transient
speed and stability, whereby a larger Dp afforded a more prominent dampening
effect, and vice versa.
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