SOLAR TRACKER POWER MANAGEMENT

Abstract

The invention relates to electric solar trackers powered by rechargeable power sources, such as rechargeable batteries and how the solar tracker is fed in order to operate. The object of the invention embraces a system and a method for operating a solar tracker mainly fed by rechargeable power sources, powered by a main power supply fed by electricity produced by a solar panel associated to the solar tracker and operated by the latter. A controller is furnished with a set of instructions aimed to manage a power flow feeding the rechargeable power sources and the operating modes for the solar tracker, either fed by the main power supply or by the rechargeable power sources.

Claims

1-14. (canceled)

15. A circuit arrangement for managing power in a solar tracker, the circuit arrangement comprising: a main solar power supply; a solar tracker; at least two rechargeable power sources connected to the solar tracker and to the main solar power supply; a controller configured to control a set of switches and arranged between: each one of the rechargeable power sources and the main solar power supply, to control an electricity flow feeding said rechargeable power source from the main solar power supply, and each one of the rechargeable power sources and the solar tracker to control an electricity flow feeding the solar tracker from said first rechargeable power source.

16. The circuit arrangement of claim 15, wherein the rechargeable power sources are defined by at least a first rechargeable battery and a second rechargeable battery independently arranged.

17. The circuit arrangement of claim 15, wherein the rechargeable power sources are respective groups of rechargeable battery cells defining battery banks.

18. A power management method for a solar tracker, the method comprising the steps of: feeding at least two rechargeable power sources with respective nominal capacity (Ah) summing up the theoretical nominal capacity (Ah) required for operating the solar tracker and connected to a main solar power supply feeding the solar tracker; controlling a set of switches arranged between: one of the rechargeable power sources and the main solar power supply, to control an electricity flow feeding said rechargeable power sources from the main solar power supply, and each one of the rechargeable power sources and the solar tracker to control an electricity flow feeding the solar tracker from said rechargeable power source, feeding at least one of the rechargeable power sources from the main solar power supply, and feeding the solar tracker from the at least one of the rechargeable power sources.

19. The method of claim 18, wherein the rechargeable power sources comprise three different power levels: a recommended operative level corresponding to a power level for the rechargeable power source to feed the solar tracker, a minimum operative level corresponding to a power level for the rechargeable power source not to feed the solar tracker, a full charge level corresponding to a power level for the rechargeable power source not to charge anymore, the method further comprising start charging any of the rechargeable power sources from the main solar power supply only when: PV power is available, and said rechargeable power source is in idle mode and below full charge level.

20. The method of claim 19, wherein at least one of the rechargeable power sources, being an active rechargeable power source feeding the tracker, is determined to have a power level below the minimum operative level; the method further comprising performing a swap so that said active rechargeable power source feeding the tracker with a power level below the minimum operative level becomes an idle rechargeable power source.

21. The method of claim 20, wherein the idle rechargeable power source has a power level greater than or equal to the recommended operative level for swap to be allowed.

22. The method of claim 20, wherein the power level of the idle rechargeable power source is below the recommended operative level; wherein the method comprises delaying the swap until recommended operative level is reached at the idle rechargeable power source.

23. The method of claim 22, further comprising: sending the solar tracker to a stow position, and turn the solar tracker off.

24. The method of claim 18, further comprising: feeding the solar tracker from all rechargeable power sources when a critical situation arises.

25. The method of claim 18, wherein the rechargeable power sources are a first rechargeable battery and a second rechargeable battery, independently arranged.

26. The method of claim 18, wherein the rechargeable power sources are groups of rechargeable battery cells defining at least two banks acting as rechargeable power sources.

27. A solar tracker comprising: a circuit arrangement for managing power in a solar tracker, the circuit arrangement comprising: a main solar power supply; a solar tracker; at least two rechargeable power sources connected to the solar tracker and to the main solar power supply; a controller configured to control a set of switches and arranged between: each one of the rechargeable power sources and the main solar power supply, to control an electricity flow feeding said rechargeable power source from the main solar power supply, and each one of the rechargeable power sources and the solar tracker to control an electricity flow feeding the solar tracker from said first rechargeable power source.

28. The solar tracker of claim 27, wherein the controller performs a power management method for a solar tracker, the method comprising the steps of: feeding at least two rechargeable power sources with respective nominal capacity (Ah) summing up the theoretical nominal capacity (Ah) required for operating the solar tracker and connected to a main solar power supply feeding the solar tracker; controlling a set of switches arranged between: one of the rechargeable power sources and the main solar power supply, to control an electricity flow feeding said rechargeable power sources from the main solar power supply, and each one of the rechargeable power sources and the solar tracker to control an electricity flow feeding the solar tracker from said rechargeable power source, feeding at least one of the rechargeable power sources from the main solar power supply, and feeding the solar tracker from the at least one of the rechargeable power sources.

Description

DESCRIPTION OF THE DRAWINGS

[0018] To complement the description being made and in order to aid towards a better understanding of the characteristics of the invention, in accordance with a preferred example of practical embodiment thereof, a set of drawings is attached as an integral part of said description wherein, with illustrative and non-limiting character, the following has been represented:

[0019] FIG. 1.- Shows an illustration depicting the state of the art where a diagram of a typical configuration of battery system with charger is represented.

[0020] FIG. 2.- Shows an electric diagram of one of the aspects of the object of the invention in a preferred embodiment wherein two rechargeable batteries, also referred as batteries throughout this document, are implemented as rechargeable power sources.

[0021] FIG. 3.- Shows a flowchart of the method of one aspect of the object of invention aimed to power management of a solar tracker, said power being provided by at least two rechargeable power sources fed by a solar powered main power supply.

DETAILED DESCRIPTION

[0022] In a preferred embodiment of any of the aspects of the invention, rechargeable power sources (1, 2) are connected to a main solar power supply (4) and to a solar tracker (3), and may be defined by at least two rechargeable batteries which nominal capacity (Ah) sums up the theoretical nominal capacity (Ah) required for feeding and operating a solar tracker (3).

[0023] In said preferred embodiment of the object of the invention, the rechargeable power sources (1, 2) are defined by a first and a second batteries each one preferably having half of theoretical nominal capacity (Ah) required for feeding and operating a solar tracker (3). By having two rechargeable batteries, the solar tracker (3) might be powered by one of the rechargeable batteries being an active battery, while the other rechargeable battery may be at idle state whilst recharging, being an idle battery.

[0024] In a yet preferred embodiment of the invention, the rechargeable power sources (1, 2) may be defined as groups of rechargeable battery cells defining banks, which may in turn be enclosed in a rechargeable battery; again, the respective nominal capacities (Ah) of the rechargeable power sources (1, 2) should sum up the theoretical nominal capacity required to operate the solar tracker (3).

[0025] A controller (not represented in figures) would be responsible for controlling power management based on certain configurable parameters such as: power levels and according to said parameters setting the first battery as active battery where power is taken from said first battery thus feeding the solar tracker (3), whereas the second battery is set in idle mode as idle battery where power is fed to the second battery from the, preferably solar powered, main solar power supply (4) connected to a solar panel (not represented in figures) of the solar tracker (3); in order to do so the controller is associated with a set of switches (Q1, Q2, Q3, Q4) preferably associated in pairs to each one of the rechargeable power sources (1,2) as follows: [0026] Between each one of the rechargeable power sources (1,2) and the main solar power supply (4); to control an electricity flow feeding said rechargeable power source (1,2) from the main solar power supply (4). [0027] Between each one of the rechargeable power sources (1, 2) and the solar tracker (3); to control an electricity flow feeding the solar tracker (3) from said rechargeable power source (1,2).

[0028] As per FIG. 2, a simple two batteries embodiment may be deployed as follows: [0029] A first switch (Q1) may be arranged between the first battery and the main solar power supply (4), acting as battery charger, to control an electricity flow feeding the first battery. [0030] A second switch (Q2) may be arranged between the second battery and the main solar power supply (4), acting as a battery charger, to control an electricity flow feeding the second battery. [0031] A third switch (Q3) may be arranged between the first battery and the solar tracker (3) to control an electricity flow feeding the solar tracker (3) from the first battery. [0032] A fourth switch (Q4) may be arranged between the second battery and the solar tracker (3) to control an electricity flow feeding the solar tracker (3) from the second battery.

[0033] Following the electric diagram of FIG. 2, and in order to describe a possible scenario where the first battery is meant to be charged, the first switch (Q1) is switched on allowing power to flow from the main solar power supply (4) to the first battery feeding the latter, whereas the second battery would feed the solar tracker (3) once the fourth switch (Q4) is switched on. Should we need charging the second battery, according to the electric diagram of FIG. 2, said second battery will then have to be fed by operating the second switch (Q2) allowing power to flow from the main solar power supply (4) to the second battery, whilst the first battery would be feeding the solar tracker (3) whilst the third switch (Q3) is switched on.

[0034] The controller may be defined by a specific device associated with the circuit arrangement or may be embedded in any one of the components of the circuit arrangement, thus furnishing said component or components of the circuit arrangement of the first aspect of the invention with instructions needed to carry out the object of the invention.

[0035] The table below shows the different operation modes according to the different combinations of states of switches (Q1, Q2, Q3, Q4) for two batteries acting as rechargeable power sources (1,2) scenario:

TABLE-US-00001 Switches Operation mode Q1 Q2 Q3 Q4 off off off off Solar tracker (3) not fed. Batteries not fed- nor charging. on off off on First battery fed- charging. Second battery feeds solar tracker (3). off on on off First battery feeds solar tracker (3). Second battery fed- charging. off off on on Batteries feed Solar tracker (3). Batteries not fed- nor charging. on on off off Solar tracker (3) not fed. Batteries fed- charging.

[0036] As per the table above, switching on one of the switches (Q1, Q2, Q3, Q4) allows current flow passing through, thus electrically connecting components associated thereof; consequently, feeding either at least one of the batteries and/or the solar tracker (3).

[0037] In a preferred embodiment of the invention any one of the rechargeable power sources (1, 2), i.e. batteries, is meant to have at least three different power levels: [0038] Recommended operative level: Minimum recommended level to start discharging the rechargeable power source (1, 2), thus feeding the solar tracker (3). [0039] Minimum operative level: Level from which it is not recommended to feed the solar tracker (3) from the rechargeable power source (1, 2). [0040] Full charge: 100% charged, level from which it is not recommended to charge any one of the rechargeable power sources (1, 2) anymore.

[0041] It is worth noting that any one of the rechargeable power sources (1, 2) may be found: [0042] Charging up to 100% power level. [0043] Charging until reaching the recommended operative level, “Battery swap delayed” in the event that the power level of one of the rechargeable power sources (1, 2) acting as active rechargeable power source, namely feeding the solar tracker (3), falls below the minimum operative level, any rechargeable power sources (1, 2) acting as idle rechargeable power source, is charged to a recommended operative level, and once this level is reached, a battery swap will be performed. [0044] Not charging because there is no PV power.

[0045] The following conditions are previously checked to start charging any of the rechargeable power sources (1, 2): [0046] 1. Availability of PV power [0047] 2. Rechargeable power sources (1, 2) in idle mode. [0048] 3. Rechargeable power sources (1, 2) not 100% charged; namely not being at full charge level.

[0049] The aforementioned battery swap is further detailed in the light of FIG. 3, a swap (normal conditions, when it goes from being active rechargeable power source to being idle rechargeable power source) is carried out when the active rechargeable power source power level is determined to be below the minimum operative level, hence said rechargeable power source (1, 2), being the active rechargeable power source, becomes the idle rechargeable power source, please note that the idle rechargeable power source had to have a power level greater than or equal to the recommended operative level for swap to be allowed. A delayed swap is performed in the event that the charge level of the idle rechargeable power source power level is below said recommended operative level, then a battery swap will not be performed until said recommended operative level is reached at the idle rechargeable power source power level, thereby delaying the battery swap. In this case, the tracker (3) is sent to a stow position and then turned off.

[0050] Should PV power be available, then charging continues until recommended operative level is reached and battery swap is accomplished, then the solar tracker (3) is turned on and starts operating. Should PV power not be available, main solar power supply (4) is sent to sleep, that is, it is put in ultra-low power mode, and only wakes up to check if there is PV power. Should PV power be available back, then the process continues where stayed.

[0051] Should a critical situation arise, namely any situation that may endanger the structural integrity of the solar tracker (3) such as strong winds that do not allow to reach the stow position, an overload of the mechanical structure of the follower due to snow accumulation, freezing of the grease of the motor reducer making tracker movement impossible, etc. In general, an extra supply of power should be required for the engine to be able to operate the solar tracker (3). All these cases would make it impossible for the solar tracker (3) to adopt its secure/stow position and therefore, it would be exposed to environmental conditions that could damage its mechanical structure; in this case, all available rechargeable power sources (1, 2) are set to feed the solar tracker (3), once the critical situation is over, normal operating mode is set back. In order to prevent the solar tracker (3) to be damaged, this condition overrides any other condition.