Harmonic Mitigation in Grid connected PV using Shunt Active Filter
Introduction:
Welcome, viewers! we will explore the concept of harmonic mitigation in grid-connected photovoltaic (PV) systems employing Syntactive Power Filters. This simulation model is designed to showcase the effectiveness of Syntactive Power Filters in reducing harmonics in grid currents generated by PV systems. Let's delve into the components, control strategies, and simulation results.
System Components:
PV Array:
Rated at 100.2 kilowatts.
Comprising 47 power strings with 10 series-connected modules each.
Boost Converter:
Connects the PV array to the inverter.
Controlled by Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT).
Inverter:
Three-phase inverter.
Controlled by voltage and current controllers.
Boosts voltage from 290V to 700V.
LCL Filter:
Connected between the inverter and the point of common coupling.
Filters out harmonics.
Grid:
Represents the utility grid.
400V grid voltage at 50Hz.
Syntactive Power Filter:
Mitigates harmonics in the grid current.
Uses hysteresis controllers and compensating current calculation.
Non-linear Load:
Diode rectifier with RL load.
Introduces harmonics into the system for testing.
Control Mechanism:
Boost Converter Control:
P&O MPPT controls the boost converter to maximize PV power extraction.
Inverter Control:
Voltage and current controllers ensure grid synchronization.
Field-oriented decoupling control used for current control.
Syntactive Power Filter Control:
Hysteresis controllers and compensating current calculation for harmonic mitigation.
Simulation and Results:
Simulation Steps:
Initial simulation without nonlinear load and Syntactive Power Filter.
Simulation with the nonlinear load.
Simulation with Syntactive Power Filter.
Grid Current Analysis:
THD analysis of grid current.
Comparison of THD before and after adding the Syntactive Power Filter.
Observations:
Without Non-linear Load:
Grid current THD within acceptable limits (3.63%).
With Non-linear Load:
THD increases due to harmonics introduced by the nonlinear load (7.23%).
After Adding Syntactive Power Filter:
THD significantly reduced to 4.85%, meeting standards.
Conclusion:
This simulation demonstrates the importance of Syntactive Power Filters in mitigating harmonics in grid-connected PV systems. The filter effectively reduces THD in grid currents, ensuring compliance with standards even in the presence of nonlinear loads.
Future Considerations:
Further exploration can involve testing the system with varying PV array sizes, different nonlinear loads, and assessing the impact of Syntactive Power Filters on system stability under dynamic conditions.
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