Adaptive MPPT for Partial Shading

January 24, 2026

Project Overview

Uneven shading on rooftop solar panels (from water tanks, trees, or chimneys) creates multiple peaks on the power-voltage (P-V) curve. Standard MPPT trackers get stuck on local, lower peaks, which causes significant energy loss. This project implements an intelligent, adaptive MPPT controller using an ESP32. The system monitors the array's electrical characteristics and switches between high-speed local tracking (Incremental Conductance) and global optimization (Particle Swarm Optimization) to ensure maximum power extraction under any shade condition.

Adaptive MPPT for Partial Shading: Switching Between INC and PSO

A practical look at an ESP32-based MPPT solar charge controller that detects partial shading in real time and switches between Incremental C...

Technical Implementation

Hybrid Algorithm Flow

Incremental Conductance (INC): Used during uniform sunlight. It converges quickly and has zero oscillations once the maximum power point is reached.
Particle Swarm Optimization (PSO): Activated when shading is detected. It initializes a "swarm" of candidate duty cycles that explore the entire voltage spectrum, crossing local valleys to find the absolute global maximum.

Shading Detection Mechanism

Power Deviation: The controller compares real-time voltage and current outputs to baseline values.
Voltage Ripple Analysis: The ESP32 high-speed ADC samples the switching ripple on the input capacitors, analyzing changes in wave shape caused by bypass diodes turning on.
In testing, this method detected shading events with 94.7% accuracy within 2.3 seconds.

Key Features

Real-Time Shading Detection: Switches tracking modes without manual configuration or scheduled sweeps.
12% to 18% Energy Increase: Field tests showed clear yield improvements under active partial shading compared to traditional trackers.
FreeRTOS Resource Optimization: Task scheduling runs the control loop on Core 0 and handles remote MQTT logging on Core 1 to prevent processing delays.

Challenges and Solutions

Sweep Efficiency: Sweeping the entire voltage range to find the global peak interrupts power delivery. This was resolved by designing the real-time shading detector so that the global PSO sweep is only triggered when a physical shading signature is identified.