How do solar trackers work?

A solar tracker system is a structural solution capable of automatically adjusting the angle of PV modules, allowing them to face the sun as directly as possible and thereby increasing power generation. Compared with fix-mounted systems, solar trackers typically enhance energy yield by 15%–45%.

Key Components

A solar tracker generally consists of the following components.

1. Structural support: Posts, beams, and purlins that secure PV modules and bear environmental loads such as wind and snow.
2. Control system: Controllers, sensors, and GPS units that compute solar position and issue actuation commands.
3. Drive system: Electric linear actuators or motors that provide movement.
4. Transmission system: Bearings, linkages, and gearboxes that transfer motion to the moving structure. Additionally, the foundation anchors the tracker to the ground.  Devices such as windspeed sensors and limit switches help ensure stable operation, and in high-wind conditions, they can adjust the system to a safe stow position.

Working Principle and Control Logic

The controller of a solar tracker send commands to the motor, driving the supporting structure to rotate so that PV modules always face the sun. The operation is an automated closed-loop control process, which can be broken down into the following steps.

1. Information acquisition. If the astronomical algorithm is applied, the controller uses date, time, and plant coordinates (latitude and longitude) to calculate the theoretical trajectory and real-time position of the sun. If light sensors are used, the sensors detect light intensity in different directions in real time, by comparing intensity, the system determines the actual position of the sun.
2. Control calculation. After acquiring solar position data, the controller computes the target angle for the PV modules. Based on this target, it generates commands for motor rotation, such as direction and speed.
3. Angle adjustment. The motor operates according to the command and, through actuators or worm gear drives, smoothly moves the structure to adjust the PV modules angle.
4. Position correction. Angle sensors or encoders are usually equipped to detect the actual angle of the tracker. This data is fed back to the controller. If there is a deviation from the target angle, the controller issues correction commands to fine-tune the position.
5. Loop and reset. From sunrise to sunset, the cycle of acquisition, calculation, execution, and correction repeats continuously. After sunset, the controller instructs the solar tracker to return to its initial position or stow position, awaiting the next sunrise.

Tracking Algorithms

Astronomical algorithm. Based on time, date, and geographic coordinates, this algorithm calculates the sun’s altitude and azimuth angles. The controller’s built-in astronomical model predicts the solar path and drives the motor to move the tracker accordingly. It’s advantage is that it does not rely on weather conditions and is convenient for coordinating multiple devices, making it widely used in large-scale projects.

Light-sensing algorithm. By installing light sensors on the solar tracker to measure irradiance in different directions in real time, the controller drives the motor so the tracker moves toward the direction of stronger light until balance is reached. It’s advantage is intuitive response and real-time feedback, with relatively simple maintenance, making it suitable for smaller-scale projects.

Conclusion

The above provides an introduction to the principles of solar tracking systems. In practice, solar trackers must withstand challenges such as the impact of wind loads on structural design, the effect of soil conditions on foundations, the durability and serviceability of equipment, and the balance between cost and energy gain. At the same time, AI algorithms are able to optimize tracking angles based on real-time weather data. High-strength, low-maintenance materials are further enhancing system reliability. Looking ahead, solar trackes are expected to become an integral component of the intelligent energy ecosystem.