The goal of a solar energy system is to efficiently turn sunlight into usable electricity. One of the challenges of this conversion is the changing environmental conditions where solar panels are typically installed. Some days are sunnier than others; therefore, panels are never consistent in their energy collection. The best way to maintain the energy harvest and efficiently convert that sunlight into usable energy is to manage how the solar panels operate.

To do this, technicians have created the Maximum Power Point Tracking (MPPT) technology. MPPT is built to optimize the interaction between the PV panels and batteries. In this article, we'll discuss what MPPT is, why it's important for maintaining efficiency, and how it impacts solar performance.

The Challenge of Variable Solar Conditions

Solar panels rarely operate under steady conditions. Even on sunny days, the sun rises in the morning, peaks in the daytime, and then sets in the evening. During this time, the angle of the sun changes, changing how much light strikes each panel at varying times. Cloud cover only complicates this unpredictability, while partial shading from objects in the environment also affects panels.

Each photovoltaic (PV) module has an ideal operating condition. Under ideal operating conditions, the panel produces maximum power. Most of the time, this ideal operating condition is not the condition the PV module is experiencing. This leads to lost energy production throughout the day.

What Is Maximum Power Point Tracking (MPPT)?

The MPPT is an advanced technology that dynamically adjusts the operating point of the PV to ensure maximum power extraction from solar panels in fluctuating conditions. The major concept of MPPT is to force the PV module to operate at the most efficient voltage (or the maximum power point). MPPT does this by checking the output of the PV module, comparing it to the battery voltage, and then converting the energy to the best voltage to get the maximum current into the battery.

Since the maximum power point shifts throughout the day, and PV modules and batteries are unable to adapt to these changing conditions on their own, the MPPT is essential for ensuring efficient collection of energy in the real world.

How Inverter Control Logic Uses MPPT

Solar inverters are responsible for converting DC to AC power, while the MPPT provides power point tracking (DC to DC conversion). These two pieces work together to ensure efficient conversion of sunlight into usable energy. In some systems, the MPPT and inverter are separate devices, and in other systems, they're integrated. Small solar systems on homes tend to have integrated systems, while larger solar arrays often have separate devices.

Inverters work by sampling the voltage and current from the array, while the MPPT searches for the optimal operating point without disrupting output. How efficiently these two systems work together — and how easily they can adapt to changing environmental conditions — depends on many factors, including whether or not the devices are integrated.

Why MPPT Matters Under Partial Shading

Partial shading of one panel can dramatically affect the energy output of the entire array, because the string of panels is limited by the lowest performing panel. When one panel's output drops, it reduces the current for the string, disproportionately reducing the array's output. Modern solutions can minimize this by managing each panel's output individually. This allows unshaded panels to reach their full potential while isolating the shaded panel.

Different System Configurations

Central inverters of the past treated solar arrays like strings of Christmas lights. When one panel's productivity stopped or slowed, the entire array was affected. Today, there are options to help maximize efficiency even when part of the solar panel is in shade.

Microinverters are small inverters that are attached to the back of each solar panel, treating each panel as a separate entity. Another option is power optimizers, which use MPPT to adjust the voltage as needed, so the system is always getting the maximum amount of power from the solar array.

Real World Considerations

The type of system that consumers should choose for their array, including whether to use microinverters or power optimizers, depends on the ordinary conditions where the solar array is being installed. Partial shading due to objects in the environment differs from shading due to cloud cover. When choosing a system, the configuration of the rooftop, local climate, and features in the environment all affect which system is best.

Tools for Monitoring

Solar technicians can track efficiency in a solar system through various means, including inverter dashboards and analytics tools. Tracking current and power can help ensure maximum efficiency in the moment. Following efficiency trends helps the solar technician determine how successful the system is over time. This allows for troubleshooting and repair that could lead to greater efficiency over time.

How to Get Started as a Solar Technician

Solar is a growing field that has become a realistic option for businesses and consumers seeking to reduce energy costs and exist more sustainably. Solar technicians are responsible for the installation, monitoring, maintenance, and repair of various solar systems for commercial and residential purposes.

If you're interested in growing your career as a solar technician, start with a Solar Technician Training program that teaches real-world skills in the maintenance and installation of solar panels. To get started with George Brown Polytechnic’s Solar Technician Training Program, call 1-888-553-5333 or contact us by email at [email protected].