MX2013014983A - System for controlling the orientation in sun-path subordinated devices. - Google Patents

Abstract

The invention refers to a diffuse control system for solar units subordinated to the sun path, the same pertaining to the field of renewable energies. The invention includes an embedded control system for controlling, in an individual manner, the solar units through a Remote Terminal Unit and a central control, which are communicated through a wireless communication network with a mesh typology. The inventive system manages the transferred data in each solar unit through a graphic interface managed by the central control. The Remote Terminal Unit calculates the sun path and modifies the position of the solar units connected to an azimuth-elevation mechanism.

Description

SYSTEM OF CONTROL OF ORIENTATION OF DEVICES SUBORDINATED TO THE PATH SOLAR FIELD OF THE INVENTION The invention is found in the field of renewable energies, particularly in the field of solar energy and control for devices designed to assemble solar units that depend on the tracking of the solar path.

BACKGROUND OF THE INVENTION A device subordinate to the solar path or solar unit; as heliostats, solar ovens, photovoltaic solar cells; It is positioned in the direction of the sun at any time of the day to capture energy, the use of solar tracking technologies increases the efficiency of solar units by one third or up to 40% compared to units that do not use this system. In order to achieve an adequate monitoring of the solar trajectory, control systems are designed, which are based mainly on the location of the sun at any time of the day and on the modification of the position of the solar unit. Solar tracking algorithms that calculate the location of the sun, based on geographic location and time, are used to design the control system.

Some of the problems that solar tracking systems present are disturbances, which are unwanted movement due to external effects, can be produced by the seeing, gravity on the solar unit and even a seismic variation.

The solar movement presents the biggest problem, because the system must adjust the position of the solar units with respect to the movement of the sun, so the control system must make the necessary adjustments with a response time that allows capturing as much of the sun as possible. solar radiation.

Chinese document CN203164725U "Tower type solar thermal thermal power generation plant heliostat field control system" describes a heliostat field control system of a solar thermal tower power plant, which includes heliostats and heliostat controls. Each row of heliostats is divided into multiple groups, each group encompassing a number of heliostats. Controllers are placed in each row, group and units of heliostats. The central computer connects with all controllers in the heliostat field. The controllers are also connected each. The control system is suitable for fields with up to thousands of heliostats. The control system reflects the principles of dispersed control.

In the Chinese document CN103235603A "Automatic tracking solar device and control method" describes an automatic solar tracking device and the control method, the device includes a mobile platform with three degrees of freedom with the circuit mounted on the platform. The main control module is responsible for the operation of the complete equipment, processing, command, coordination and management of the device core. The invention automatically follows the sun, with a reasonable structure, stable circuit operation, high efficiency and less affected by external conditions.

In comparison with the documents cited above and the revised technology, the control system provides the solar units with an individual power supply and communicate wirelessly, since the use of cables can propagate the damage to the system if it is struck by lightning . This individual power supply guarantees that in case of any failure in the system, only one solar unit will be affected and not the entire system. In addition to each solar unit calculating the optimal position to be placed, the central computer only sends a record of date and time as a history, but each unit will be independent and will have its own embedded control system.

OBJECT OF THE INVENTION This invention consists of a method for tracking the solar path by means of a diffuse control and a wireless network of communications of mesh type for solar units with azimuthal and elevation movement. Each solar tracking mechanism contains a digital signal processor that is responsible for communication between the central control (PC) and the transmission modules that work at a frequency of 2.4 GHz. The actuators to be controlled are direct current (DC) motors with brushes, powered by a system of photovoltaic solar panels.

BRIEF DESCRIPTION OF THE INVENTION The control system of the field of solar units includes an embedded system to control individually the solar units, the system has an RTU (Remote Terminal Unit) and a central control or BTU (Central Base Unit), communicated through a wireless communication network with mesh topology. Through a graphical interface the BTU administers the data sent by the solar units and controls the operation in a general way. The RTU calculates the solar path and modifies the position of the solar units connected to an azimuth-elevation mechanism. The control method calculates the position of the sun by azimuth and elevation, considering the geographical position in addition to the date and time at the time of calculation, to later calculate the optimal position of the solar unit.

DESCRIPTION OF THE FIGURES Figure 1 is a schematic representation of the wireless communication network with mesh topologies (3) and (6) of the solar units (4), which are composed of the Central Base Unit (1) and (2), and the embedded system for each solar unit (5).

Figure 2 is a schematic representation of the flow diagram of the control process of the solar units, which consists of the following elements: Start (7), Receive (8) where status, date and time are processed; Read status (9), Calculate (10) where the azimuth and elevation angles are calculated, Set (11) where the results of the previous calculations are established, Receive (12), Read encoder (13) where they are read the actual angles of the solar unit at the time, Control Algorithm (14) and Move the motor (15) which performs the adjustment movement of the solar unit.

DETAILED DESCRIPTION OF THE INVENTION The control system of the field of solar units is constituted of a central control or BTU (Central Base Unit) (1) and (2); and of an individual embedded system for each of the solar units to be controlled or RTU (Remote Terminal Unit) (5), communicated through a wireless communication network with mesh topology (3) and (6).

The BTU, (1) and (2), manages and controls the operation of the field of solar units (4) sending the status of each one, which is defined as Stop (stopped), Start (start), Off (off) and Safe (safe position).

The central control (1) and (2) also sends the date and time for each individual system to perform the calculation of its current orientation with respect to the position of the sun and the position of the solar units (4) with respect to the receiver. The BTU (1) and (2) receives the information of all the solar units (4) individually beginning with the identification number (between 0 and 65535), followed by the orientation values (elevation angle and azimuth angle) and the battery level of the RTU (5).

The RTU (5) is an embedded system mounted on the base of each solar unit, which calculates the solar path and modifies the orientation of the tracking unit connected to an azimuth-elevation mechanism, with respect to a fixed objective by means of of a digital signal processor (DSP) designed to support motor control applications. Each RTU (5) controls the sending and receiving of information with the central control wirelessly (3) and (6), the reading of the position of the solar unit (4) by means of two absolute rotary encoders, the movement of two motors direct current by means of pulse width modulation (PWM) signals, reading a panel with emergency stop button and displaying the data on an LCD screen.

The control algorithm (4) calculates the position of the sun using horizontal coordinate formulas (azimuth and elevation) taking as data the geography position of the solar unit (longitude and latitude) and the date and time at the time of calculation. Subsequently the calculation of the desired orientation of the tracking unit is made taking as data the position of the sun at the time of calculation and the position of the solar unit with respect to the fixed receiver. The algorithm also reads the control status (stop, start, off and safe) and depending on its value modifies the orientation of the solar unit.

Claims (3)

CLAIMS Having described the invention, it is considered as a novelty and, therefore, what is contained in the following clauses is claimed:

1. An orientation control system for devices subordinate to the solar path (4) characterized by an embedded system to individually control the solar units or RTU (Remote Terminal Unit) (5) and a central control or BTU (Central Base Unit) (1) and (2), communicated through a wireless communication network with mesh topology (3) and (6).

2. An orientation control system for devices subordinate to the solar path according to claim 1 characterized by the movement of two direct current motors by means of pulse width modulation (PWM) signals.

3. A control system for orientation of devices subordinate to the solar path according to claim 1, characterized by a control algorithm (14) that calculates the position of the sun by means of horizontal coordinate formulas (azimuth and elevation) taking the geography position as data of the solar unit (longitude and latitude) and the date and time at the time of calculation, in addition the algorithm reads the control status (stop, start, off and safe) and depending on its value modifies the orientation of the solar unit.