Current Harmonic mitigation in Grid tied solar pv system
Introduction:
Welcome to LMS Solution! In this blog post, we'll explore the topic of harmonic mitigation in a grid-connected solar PV system using an active current coefficient control approach. Harmonics in the grid can significantly impact the quality of the current, and we'll see how this issue is effectively addressed through advanced control techniques.
Problem Statement:
When non-linear loads are introduced between the grid and a solar PV system, harmonic distortion in the grid current can exceed acceptable limits. In this video, we observe a Total Harmonic Distortion (THD) of around 22.24%, which can adversely affect the performance of other connected systems. To mitigate this issue, an active current coefficient control concept is introduced.
System Components:
The solar PV system comprises a PV array with seven series strings, a boost converter, and a voltage source inverter connected to the grid. The boost converter is controlled by Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT), ensuring optimal power extraction from the PV array. The voltage source inverter utilizes the active current coefficient control approach to mitigate harmonics in the grid.
Active Current Coefficient Control:
The active current coefficient control concept involves calculating the active current coefficient for each line in the load. By measuring the load current and grid voltage, the system determines the coefficients and uses them to control the inverter. This method ensures that the inverter supplies compensation currents, maintaining sinusoidal grid currents.
Simulation Results:
The simulation demonstrates the system's robust performance under various conditions. When irradiation changes, the inverter adapts to supply real and reactive power to the load, minimizing dependency on the grid. Additionally, during voltage distortion and sag/swell conditions, the inverter compensates effectively to maintain sinusoidal grid currents.
Conclusion:
The active current coefficient control approach proves to be a powerful solution for harmonic mitigation in grid-connected solar PV systems. By dynamically adjusting compensation currents based on load conditions, the system ensures a high-quality grid current, reducing the impact of harmonics on the overall power network.