Application example: solar tracker (photovoltaic)

Solar power plants are essential to achieving the transition to renewable energy. A PV (photovoltaic) panel provides maximum yield when the sunlight strikes the panel at a normal angle (90 degrees).

Because the sun moves from East to West during the day, the peak potential yield occurs at about midday, when the sun is highest, and the angle of the sunlight is closest to 90 degrees to the panel surface. However, the yield from a single panel can be increased over the entire day by continuously adjusting the angle of the panel to follow the sun, using a Solar tracker. A Solar tracker consists of a control unit, a motor, and a position sensor. Although a rotary encoder can be used for this purpose, the inclinometer is increasingly becoming the preferred means of measuring the momentary angle of the PV panel.

An inclinometer directly measures the angle of the PV panel with reference to the direction of the gravitational force. Unlike indirect angular sensors, it requires no artificial reference, such as a magnet or laser beam, and can therefore be mounted virtually anywhere on a PV panel or synchronous group of PV panels. Moreover, it is not adversely affected by dynamic effects of the tracking movements, as these are extremely slow and small.

The inclinometer sends the measured angle of the PV panel to the control unit, which in turn instructs the motor to adjust the angle of the PV panel such that the panel is always perpendicular to the incoming rays of sunlight, according to a stored algorithm).

This results in optimum conversion efficiency from sunrise to sunset, increasing the yield by around 20% compared to fixed panel arrays. This significant boost in yield means the investment in solar tracking is quickly repaid.

Solar tracking generally entails mounting an array of PV panels on a mechanical rack, with a single inclinometer per array. Most solar tracking installations use a single axis solar tracker, which controls only the daily east-west movement. However, the yield can be maximized by using a dual axis tracker to adjust for the changing elevation of the sun during the seasons. By employing a dual axis inclinometer, the north-south tilt of the panels can also be measured and mechanically adjusted to keep the panels orientated normal to the sun, at every moment of daylight throughout the year.

Sensor:

• Single axis Inclination sensor QG30, with optional low pass filter
• Dual axis Inclination sensor QG40 or QG40N, with optional low pass filter

Specific:                          

• 1 or 2-axis ±90° (output 4-20mA / 0.5-4.5V)

More information

Would like to know more about this application or questions about another solution? Please contact your local distributor.