I understand that you are trying to implement Battery charging using PV panel with Buck converter without MPPT. After running the simulation, there is a drop in the voltage of Solar panel to that of the battery voltage. This issue can be due to multiple reasons as:
- The buck converter is not regulating properly. Ensure that the input voltage range of the buck converter is correctly set to handle the PV panel’s output. Also check the duty cycle settings for the voltage conversion.
- If the PV panel is not generating enough power, the voltage will drop when the load (battery) is connected.
- Without MPPT, the control algorithm might not be effectively managing the power transfer. So, you can implement a basic control method to regulate the voltage and current. For example, using a simple voltage feedback loop to adjust the duty cycle of the buck converter. You can refer the below example https://www.mathworks.com/help/sps/ug/buck-converter-voltage-control.html
- Incorrect parameters for the PV panel, buck converter, or battery in your Simulink model. Make sure that the PV panel’s characteristics (like open-circuit voltage and short-circuit current) are accurately represented.
- Ensure that the initial conditions for the PV panel and battery are set correctly. And the PV panel should start with an open-circuit voltage higher than the battery voltage.
By checking the above conditions in the Simulink Model, you can try to rectify the issue.
