Implementation of Three-Phase Grid-Connected Solar PV System
Setting Up the Model
To begin, open MATLAB and access the library browser. Navigate through the following directories: Simscape > Electrical > Specialized Power Systems > Renewables. Here, select the solar component and place it into your model workspace.
Next, connect a constant block for irradiation and temperature:
Set irradiation to 1000 W/m².
Set temperature to 25°C.
This establishes the baseline conditions for your solar PV system.
Configuring Circuit Components
In this section, we will configure the solar array and its associated components. For the simulation, we’ll set up a solar array consisting of 10 series and 47 parallel strings, with each panel rated at 230 W. Key specifications include:
Open circuit voltage: 36.3 V
Voltage at maximum power point: 29 V
Short circuit current: 7.84 A
Current at maximum power point: 1.35 A
Next, we need to connect a boost converter after the solar panel. This requires components such as IGBTs, diodes, capacitors, and inductors. Here's how to set them up:
Use a resistance of 1 Ω and capacitance of 1000 µF for the circuit.
Select an inductor value of 1.5 mH.
Implementing the MPPT Algorithm
To optimize the power output from the solar panels, we will implement an MPPT algorithm. This process involves several key steps:
Initialize parameters for voltage and power.
Create a loop to continuously adjust the reference voltage based on real-time conditions.
The MPPT algorithm will monitor the voltage and current, adjusting the reference voltage as needed to maximize power extraction. This is accomplished by comparing current and previous power values and updating the reference voltage accordingly.
Designing the Inverter
With the solar array and MPPT algorithm in place, it’s time to design the three-phase inverter. This involves:
Connecting six IGBTs to create the inverter circuit.
Implementing filters to manage voltage and current output.
Use measurement blocks to monitor the inverter’s performance, ensuring that you can capture both voltage and current data. Additionally, apply coordinate transformations from ABC to Alpha-Beta and DQ to facilitate better control.
Simulation and Results
Once the model is complete, run the simulation to observe how the system responds to changes in irradiation. For instance, setting the irradiation to 500 W/m² will demonstrate a reduction in power output, showcasing the system's efficiency and responsiveness.
The results illustrate the impact of varying radiation levels on power generation, providing valuable insights into the system's performance under different conditions.
Conclusion
Setting up a three-phase grid-connected solar PV system in MATLAB is a detailed process that encompasses model configuration, component selection, algorithm implementation, and simulation. By following the steps outlined above, you can effectively create and analyze a solar PV system, gaining a deeper understanding of its operation and efficiency.
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