PV MPPT Charger Control for Battery in MATLAB Simulink

This product presents a MATLAB/Simulink model of a PV-based MPPT battery charging system with overcharge protection. The system includes a solar PV array, P&O MPPT controller, PWM-controlled buck converter, lithium-ion battery, and SOC-based charging protection logic.

The main objective of this model is to extract maximum available power from the PV panel and safely charge the battery. The P&O MPPT controller tracks the maximum power point of the PV array and controls the buck converter duty cycle. When the battery SOC reaches 100%, the MPPT control is disabled and the buck converter switching operation is stopped to protect the battery from overcharging.

The simulation clearly shows PV voltage, PV current, PV power, battery voltage, battery current, battery power, and battery SOC response under different operating conditions.

Specification

Working

The PV array receives irradiance and temperature as input signals. The PV voltage and PV current are measured and given to the P&O MPPT controller.

The P&O MPPT controller calculates the change in PV power and adjusts the duty cycle to operate the PV system near the maximum power point. The generated duty cycle is applied to the PWM control circuit, which drives the switching device of the buck converter.

The buck converter steps down and regulates the PV output voltage to charge the 12 V lithium-ion battery. During charging, the battery current and battery power appear as negative values due to the Simulink battery measurement convention. This indicates that the battery is absorbing power from the PV system.

As the battery charges, the SOC gradually increases from 99.7% to 100%. Once the SOC reaches 100%, the protection logic disables the MPPT control signal and stops the buck converter switching operation. This prevents additional charging current from flowing into the battery and protects the battery from overcharging.

After the buck converter is stopped, the battery current becomes nearly zero, the battery power becomes nearly zero, and the SOC remains constant at 100%.

Simulation Result Highlights

Operation Explanation

• Solar irradiance and temperature are applied to the PV array.

• PV voltage and PV current are measured.

• PV power is calculated using PV voltage and PV current.

• The P&O MPPT controller tracks the maximum power point.

• The MPPT controller generates the duty cycle for the buck converter.

• The PWM circuit produces switching pulses for the converter switch.

• The buck converter transfers controlled PV power to the battery.

• The lithium-ion battery charges and its SOC increases.

• The SOC protection logic continuously monitors the battery SOC.

• When SOC reaches 100%, the MPPT controller is disabled.

• The buck converter switching pulses are stopped.

• Battery charging current becomes nearly zero to avoid overcharging.

• Battery SOC remains constant at 100% after full charge protection.

Use Cases