College - Author 1
College of Engineering
Department - Author 1
Electrical Engineering Department
Degree Name - Author 1
BS in Electrical Engineering
College - Author 2
College of Engineering
Department - Author 2
Electrical Engineering Department
Degree - Author 2
BS in Electrical Engineering
College - Author 3
College of Engineering
Department - Author 3
Electrical Engineering Department
Degree - Author 3
BS in Electrical Engineering
Date
6-2026
Primary Advisor
Dale Dolan, College of Engineering, Electrical Engineering Department
Abstract/Summary
Unlike an ideal DC Power Supply, a solar panel does not operate with linear I-V Characteristics. The voltage and current characteristics of a solar panel change based on irradiance, temperature, weather conditions, and load demand. Because of these factors, solar panels do not always operate at their Maximum Power Point, which can lead to significant power losses. Maximum Power Point Tracking is used to adjust the panel operating point so that more usable power can be delivered to the load.This project developed a Maximum Power Point Tracking system using an STM32 Nucleo-L4A6ZG microcontroller and an LT8705A DC-DC converter stage. The LT8705A was selected because it is a four-switch buck-boost controller, allowing the system to operate when the input voltage is above, below, or near the desired operating voltage.The system is organized into hardware and software subsystems. The hardware includes voltage sensing, current sensing, the LT8705A buck-boost power stage, and STM32 control circuitry. The software includes ADC sampling, power calculation, MPPT control logic, DAC output control, fault detection, and UART display output. Fault conditions are handled through the LT8705A shutdown behavior and are displayed on the serial monitor for debugging and monitoring. The final design work focused on verifying STM32 voltage and current measurements, confirming that the control output can produce measurable changes in the LT8705A operating point, and preparing the system for full MPPT validation. Major technical considerations included ADC noise, current and voltage measurement accuracy, MPPT command saturation, converter stability, and reliable fault detection and recovery. Overall, this project provides a complete design foundation for an STM32-controlled MPPT buck-boost converter.
URL: https://digitalcommons.calpoly.edu/eesp/737