Automatic biaxial sun tracker (heliostat)

In the renewable energy field El.Ma. is currently engaged in the development and realization of solar systems for the electrical and thermal energy cogeneration, mainly of parabolic concentrators and based on Fresnel lenses.

The solar concentrators technology has to follow an on-going and exact research about solar radiation with the optimum angle on the receiver located on the focus line, which can be thermal-thermodynamic or photovoltaic, so that solar beams are as much parallel as possible to the parabolic system axis.

Obviously, a dish parabolic system should dispose on an automatic two-axis sun following system (azimuth and elevation), while a linear focus cylindrical system can dispose on an automatic one-axis sun following system (azimuth or elevation), by keeping the other axis constant during the time.

It is interesting to notice that also in case of traditional PV systems working with flat solar panels, in comparison to the traditional fixed installation with azimuth and tilt costant during the time, the right orientation through a sun following system allows to optimize the efficiency up to 35% compared with the traditional installation with azimuth and tilt constant.

By connecting to this link it's possible to view in real-time the parameters of a small monoaxial PV solar plant, installed by El.Ma. in order to test this kind of technology.

For these reasons El.Ma. has planned and realized an automatic sun following system based on real-time calculation of solar coordinates in relation to hour, day, latitude and longitude with the maximum theorical accuracy (greater than 0.010°).

The control board presents the following features:

low consumption and low cost 16 bit microcontroller;
possibility to connect different types of motors;
CAN interface with protocol CAN open and DSP402 Drive Profile Interface;
2xRS232 interfaces;
LCD display for showing all data and keyboard for setting all parameters and moving system in manual mode;
DCF77 for automated setting of date and hour;
sensors for monitoring wind speed (anemometer) and temperature (4xPT100);
management of limit switches;
management of 4 digital I/O.

Actual drivers can manage two kinds of motors:

DC motors with encoder with voltage 24V and inrush current up to 10A (mosfets are on board and motors are controlled in PWM with variable duty cycle);
stepper motors up to 3 Nm (they can manage also greater torque values - up to 6 Nm - but speed decreases).

In both cases the movement (interval is setable on angle or time) is done with speed/position control.

If greater torque/power values are needed, the electronic control board can be customized on customer's requirements; in fact in this case it's possible to connect commercial motor drivers working on CAN with CANopen DSP402 Drive Profile Interface protocol.

Originally, the sun tracker is biaxial i.e. it manages independently the two polar axes (azimuth and elevation). However, it can easily settled in order to move only an axis (e.g. the azimuth one), keeping the other one as fixed (tilt): in this case, it is possible to move two different strings (or linear solar concentrators) through just one tracker.

An easy manual configuration of parameters (GPS coordinates, reduction ratios, tracking interval and cinematic values) is assured by onboard keyboard and display; obviously these settings can be applied through a PC/notebook connection via RS232 serial port thanks to dedicated software.

In the future a GPS and a compass, which communicate through the NMEA0183 protocol, will allow the system to obtain latitude/longitude and the North-South direction.

Moreover, it's previewed the connection with a sensor in order to calibrate the system, to compensate installation errors.

In order to synchronize more panels or solar concentrators (array) it's previewed the development of a master board based on the high performances process control, with a 32 bit CPU and 10/100 Mbit LAN interface with protocols TCP/IP, UDP/IP, ICMP and HTTP: a web server will be included in order to allow an easy configuration of the solar concentrator and to display real-time following data:

electrical parameters;
thermal-termodynamic parameters;
temporal parameters;
solar coordinates;
measurement of luminous intensity on orientation sensors;
chronological report of possible malfunctions.

Through the supervision software installed on a PC, it will be possible to control a plant; the program will allow to monitor all information and the plant functioning. Moreover, it will be possible to send specific orders to a single panel and/or to groups of panels, firmware updates etc., in local or remotely, via Internet or through a modem GSM/GPRS.

If you need further details or information about the purchase of the sun following system, please fill the contacts page.


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The solar concentrators technology has to follow an on-going and exact research about solar radiation with the optimum angle on the receiver located on the focus line, which can be thermal-thermodynamic or photovoltaic, so that solar beams are as much parallel as possible to the parabolic system axis. Obviously, a dish parabolic system should dispose on an automatic two-axis sun following system (azimuth and elevation), while a linear focus cylindrical system can dispose on an automatic one-axis sun following system (azimuth or elevation), by keeping the other axis constant during the time. It is interesting to notice that also in case of traditional PV systems working with flat solar panels, in comparison to the traditional fixed installation with azimuth and tilt costant during the time, the right orientation through a sun following system allows to optimize the efficiency up to 35% compared with the traditional installation with azimuth and tilt constant. By connecting to this link it's possible to view in real-time the parameters of a small monoaxial PV solar plant, installed by El.Ma. in order to test this kind of technology. For these reasons El.Ma. has planned and realized an automatic sun following system based on real-time calculation of solar coordinates in relation to hour, day, latitude and longitude with the maximum theorical accuracy (greater than 0.010°). The control board presents the following features: low consumption and low cost 16 bit microcontroller; possibility to connect different types of motors; CAN interface with protocol CAN open and DSP402 Drive Profile Interface; 2xRS232 interfaces; LCD display for showing all data and keyboard for setting all parameters and moving system in manual mode; DCF77 for automated setting of date and hour; sensors for monitoring wind speed (anemometer) and temperature (4xPT100); management of limit switches; management of 4 digital I/O. Actual drivers can manage two kinds of motors: DC motors with encoder with voltage 24V and inrush current up to 10A (mosfets are on board and motors are controlled in PWM with variable duty cycle); stepper motors up to 3 Nm (they can manage also greater torque values - up to 6 Nm - but speed decreases). In both cases the movement (interval is setable on angle or time) is done with speed/position control. If greater torque/power values are needed, the electronic control board can be customized on customer's requirements; in fact in this case it's possible to connect commercial motor drivers working on CAN with CANopen DSP402 Drive Profile Interface protocol. Originally, the sun tracker is biaxial i.e. it manages independently the two polar axes (azimuth and elevation). However, it can easily settled in order to move only an axis (e.g. the azimuth one), keeping the other one as fixed (tilt): in this case, it is possible to move two different strings (or linear solar concentrators) through just one tracker. An easy manual configuration of parameters (GPS coordinates, reduction ratios, tracking interval and cinematic values) is assured by onboard keyboard and display; obviously these settings can be applied through a PC/notebook connection via RS232 serial port thanks to dedicated software. In the future a GPS and a compass, which communicate through the NMEA0183 protocol, will allow the system to obtain latitude/longitude and the North-South direction. Moreover, it's previewed the connection with a sensor in order to calibrate the system, to compensate installation errors. In order to synchronize more panels or solar concentrators (array) it's previewed the development of a master board based on the high performances process control, with a 32 bit CPU and 10/100 Mbit LAN interface with protocols TCP/IP, UDP/IP, ICMP and HTTP: a web server will be included in order to allow an easy configuration of the solar concentrator and to display real-time following data: electrical parameters; thermal-termodynamic parameters; temporal parameters; solar coordinates; measurement of luminous intensity on orientation sensors; chronological report of possible malfunctions. Through the supervision software installed on a PC, it will be possible to control a plant; the program will allow to monitor all information and the plant functioning. Moreover, it will be possible to send specific orders to a single panel and/or to groups of panels, firmware updates etc., in local or remotely, via Internet or through a modem GSM/GPRS. If you need further details or information about the purchase of the sun following system, please fill the contacts page.