In recent decades, the concept of environmental degradation has manifested itself as an imminent threat, prompting world leadership to forego environmentally harmful habits. A major part of this change is the shift towards renewable energy sources, solar energy in particular. According to the Tracking Power 2019 report by the International Energy Agency, solar PV generation registered an impressive 31% increase in 2018; the highest of all renewable technologies.

How to automate solar panels

Figure 1: A PV Panel Array for Harvesting Solar Energy

This rising trend of solar power has also encouraged a number of innovations within this industry. This article discusses a rising trend in the solar panel industry: solar panel automation. A comprehensive breakdown of how solar automation systems work and what they comprise of will be discussed, giving you a key insight into this trend and how it may be worthwhile for you.

Automatic Solar Panels

Solar panels, technically known as Photo-Voltaic (PV) modules, are an excellent means of harvesting the unlimited, highly reliable energy provided by the sun.

Solar panels were previously mounted in a fixed position in a certain location, slant, and direction. As the sun is not fixed in the sky, this is not a fully optimal setting as it follows a trajectory from sunrise to sunset. Sunlight was almost never exactly perpendicular to the plane of the solar panels, which is a condition required for maximum energy conversion.

This flaw in fixed solar panel systems led to the idea of ‘solar tracking’. Solar tracking systems consists of an automated system to lift and tilt solar panels, allowing them to follow the path of the sun throughout the day, guaranteeing maximum insolation. Solar tracking has gained massive popularity owing to its better ROI and has been implemented across the industry, from massive solar farm automation projects to domestic units.

The Solar Tracking Solution Kit

Automated linear actuator solutions can easily be incorporated into your solar panel application; by considering the components discussed below, it will make the transition as seamless as possible.

Solar Panel Control Box

The most crucial element of a solar tracking unit is its control system. A solar panel control system is usually a closed-loop mechanism operated via controller hardware.

Linear actuator for solar tracker

Control System Basics

The basic components of a control system are as follows:

  • Controller: The central unit of a controller contains a programmed logic for running the system successfully. In this context, this controller is usually a PLC that is capable of tasks such as calculating the sun’s position, assessing weather conditions, deploying safety protocols of the panels, etc. It is the main decision-maker regarding how the tracking is performed.
  • Sensors: The sensors act as input to the controller which in turn makes its decisions. Solar panel systems use sensors for variables like sunlight irradiance, wind speed, panel slope, etc. All these are fed into the PLC’s program, which uses it to equate its actions.
  • Actuators: These are the outputs of the system. Based on the controller’s output signal, these actuators cause the system to move in the desired way. A common actuator for a solar tracking system is a linear actuator.
  • Feedback: This is not a physical component but is equally as important as the aforementioned. When operating on a closed-loop, the controller not only relies on sensors from input points but also on sensors integrated into the actuators. This means that if the actuators are not acting perfectly, these feedback signals compute an error that the PLC is programmed to deal with. Closed-loop control systems make more accurate and energy-efficient solar trackers.

PLC for a solar tracker

Qualities of a Good PLC

When choosing a PLC for a solar tracker, you should keep in mind the core needs of your control box.

  • Durable: It must withstand the area’s climate and survive outdoors for years.
  • Computing Power: It must have ample computing power to run your tracking program.
  • Communication Modules: Depending upon the I/O methods your control system comprises, your PLC must have the correct protocol provision to ensure quick communication between devices.
  • Easy to Use: A PLC is a technical device. It is always best to go for an option that has an easy interface.

Solar Tracker Actuator

The second part of the solar tracking solution kit is its actuation system. A below-par actuation system may not complement your PLC, might require extra maintenance, and can even lead to financial loss by failing altogether.

There are numerous applications for an actuator in solar tracking, depending upon the type of configuration employed. A single-axis solar tracker requires just one linear actuator for solar panels, which keeps the panels in sync with the sun in either the North-South axis or the East-West axis. A dual-axis setup warrants the use of two actuators, one for each axis; this is understandably the most precise setup.

Some solar trackers make use of motors instead of linear actuators. A prime example is setup with a rotating base, which includes an actuator to rotate solar arrays as the sun changes position.

While there are innumerable factors that must be considered before finalizing your actuators, we have picked the most important ones you must bear in mind when engineering solar trackers.

Force, Power, & Speed Ratings

The primary job of an actuator is to produce motion, and these ratings are what determine the kind of motion an actuator produces. You can compute the power and force requirements of your actuators through a basic force analysis. Static and dynamic loads should both be included as you do not want your actuator to lose performance while moving your panels.  

The speed rating of actuators is not that important in the design of solar tracking. The reason behind this is that the sun moves very slowly across the sky. Consequently, the actuators do not have to move swiftly. An advantage of the low-speed requirement is that it keeps the power rating down, even though the force/torque requirement is generally high due to the weight of the panels.

Environmental Protection Rating

This is a specification you have to choose carefully. Since solar tracker actuators operate outdoors, they are often exposed to dirt and moisture. Hence, environmental protection ratings of actuators must be on the upper end, preferably IP65 or more.

Another important consideration stemming from the environment is mounting. The linear actuator for a solar tracker is ideally mounted with the motor side up. This is to prevent the dirt/water build-up on the actuator shaft from penetrating its seals and causing damage.

Feedback

If a closed-loop system is opted for, the feedback unit of the actuator must be up to the mark. The encoder your actuator packs must be of the desirable rating, as precise feedback leads to better positioning and power generation. A low-rated encoder can prove to be counterproductive as it can lead to huge error signals that can meddle with the PLC logic.

Mechanical Strength

The final point in our list is the mechanical integrity of the chosen actuator. The actuator itself must be rigid and strong enough to withstand the forces subjected to it. For example, if an application is using a linear actuator to raise solar panels, it should not buckle under the load it faces. An important consideration regarding mechanical strength is holding force. Extreme weather conditions like strong winds are a possibility that cannot be ignored. In this case, the actuators must exhibit enough holding force to keep the panels in place or keep them stowed.

Linear actuator PA-100 model by Progressive Automations used in solar energy industry

Where to Find the Ultimate Solar Panel Motor Kit?

The purpose of this article is to enlighten you about solar tracking and share the solution kit required for this technology. If you find yourself interested in automating your solar panel systems, we would like to point you to our catalog of high-force linear actuators, particularly our PA-100 electric linear actuator that is designed specifically for solar applications.

We would be happy to offer more advice and guidance on this topic – feel free to contact us with your queries and one of our expert engineers will gladly help you.