WO2013164500A1

WO2013164500A1 - System for managing the power of led luminaires

Info

Publication number: WO2013164500A1
Application number: PCT/ES2013/000112
Authority: WO
Inventors: Axelle VERGES; Alessandro Caviasca; Oscar SACRISTA; Jordi VERDAGUER; Eduardo VILA
Original assignee: Jvv Grup Montajes Y Desarrollos De Proyectos Electricos, S.L.; Studio Intinerante Arquitectura, S.L.
Priority date: 2012-05-03
Filing date: 2013-05-02
Publication date: 2013-11-07
Also published as: ES2432840B1; ES2432840A1; WO2013164500A8

Abstract

The invention relates to a system for managing power in LED luminaires (1) powered by a standalone photovoltaic solar energy system with photovoltaic solar panels (2) which charge a battery (3), which powers the luminaires (1). The system integrates, in a single device, a microprocessor provided with an MPPT algorithm, which makes it possible at all times to store in the battery (3) the maximum power from the solar panels (2), and a second microprocessor provided with data entries on the state of charge of the battery (3), and a predictive algorithm which calculates the power to be delivered from the battery (3) to the luminaire (1), according to one or more of the following pieces of data: date and time, geographical coordinates and state of charge of the battery (3).

Description

D E S C R I P C I O N

"System for power management of LED luminaires" Technical sector of the invention

The present invention relates to a system for the management of power in autonomous electrical consumption, and for the rationalization of energy consumption, formed by an autonomous source of renewable energy, for example solar, and a consumption of variable electrical power, for example , although not exclusively, one or several LED luminaires.

The system involves computing means (a microprocessor) implemented with an MPPT algorithm of the type of current efficiency, which allows at all times to store the maximum power in the battery, at a voltage such that the power is maximum for the radiant power captured by the panels at all times.

Background of the invention

Photovoltaic solar panels have a complex relationship between their operating environment and the maximum power they can produce. The behavior of the solar panel is not linear, which is characterized by the filling factor, FF, which is defined as the ratio between the maximum removable power of the solar panel and the product VQ _C I _SC . (maximum voltage and maximum intensity, respectively, of the first quadrant; see Fig. 1). For each set of operating conditions, solar panels have a unique point where the current (I) and voltage (V) values of the panel provide maximum power output. These values correspond to a specific value of the load resistance equal to V / 1, in accordance with Ohm's Law. The power will be given by P = V I. A photovoltaic panel has an approximately exponential relationship between current and voltage. From the basic circuit theory, the power delivered to or from a device is optimal (a maximum) when the derivative (ie the slope) dl / dV of the curve lV It is equal to the quotient l V (where dP / dV = 0). This point is known as Maximum Power Point (MPP), and corresponds to the "knees" - as it is called on the slang - of the curve of Fig. 1, in which a value of current l _max and voltage V _max .

In this Fig. 1 only two curves are shown: a lower nocturnal curve (N), for a solar irradiation (for example W / m ² ) null or very low and a diurnal upper curve (D), in which the intensity supplied It has positive values, up to a V _oc value of the voltage, changing the direction current from this value. For each value of solar irradiation there is a characteristic D curve.

In many applications it is important to track this MPP, to keep the maximum power delivery. For this, the maximum power point tracking devices (MPPT, or "Maximum Power Point Tracking", in English language) are known.

The MPPT, or follower of the maximum power point, is a DC / DC converter controlled by a microcontroller that carries an integrated algorithm to maximize the production of a panel, some work with sensors that monitor radiation and temperature, for example: when the temperature from the panel increases, the voltage that is capable of supplying the module decreases, but at the same time the intensity also increases. If the MPPT control decreases the voltage, causing a rise in intensity, the power remains substantially constant. The same, but vice versa, is applicable when the radiation on the photovoltaic solar panel decreases, in cold conditions, clouds, sunrise and sunset. The earnings can be between 20% and 40%.

MPPT devices use different types of algorithms, for example MPPT of the current efficiency type, which allows to store the maximum power in the battery at all times, at a voltage such that the power is maximum for the radiant power captured by the panels at every moment. The MPPT of the present invention uses such an algorithm. The captured electrical energy is delivered to a battery, managed by the MPPT, and the battery feeds the electrical consumption (luminaires, irrigation controls, small motors, ...) and the surplus over consumption is stored in the battery. These known systems, of which many embodiments are known, have drawbacks. The first is that in the absence of demand, excess energy can be sent to electricity consumption, either from the battery or directly from the solar panels. This is the case of a luminaire that stays on all night unnecessarily. If it is an autonomous luminaire, for example in an urban space, without power supply, the battery is discharged and cannot power other devices, for example, the next day is cloudy.

On the other hand, the consumptions are programmed statically, that is, a fixed electric power is assigned to each time slot to be delivered to the luminaire (or other consumptions) from the battery, without taking into account the actual present conditions or in terms of availability of Radiant energy, no state of charge of the battery, nor demand of real power required by the luminaire.

Finally, for a specific geographical location of the luminaire there are historical data and controllable geo-climatic conditions that would make the availability of radiant energy predictable for each day of the specific year. In addition, the consumption characteristics of a particular installation could also be predictable. However, in current autonomous photovoltaic luminaire devices it is not known that they provide this predictability functionality, but that from the battery they deliver all the power demanded by the consumption or set for it if taking into account the real or predictable practical circumstances.

In short, energy is not accumulated or consumed effectively. The present invention aims to provide a system that allows to solve these problems, rationalize energy consumption and adapt to the real demand and in a predictable way both the battery charge and the energy delivery. Explanation of the invention.

To this end, the object of the present invention is a system for the management of instantaneous power in luminaires powered by an autonomous system of photovoltaic solar energy, comprising photovoltaic solar panels that charge a battery, which feeds the luminaires, which in Its essence is characterized in that it integrates, in a single device, two functionalities: - First computing means with an MPPT algorithm of the type of current efficiency, which allows at all times the first functionality to store in a battery the maximum power from the solar panels, and - a few second computing means, provided with data inputs on the state of charge of the battery, and a predictive algorithm that has the functionality of calculating the power to be delivered from the battery to the luminaire, depending on the day of the year and time, geographic coordinates, and battery charge status.

The first computing means and the second computing means can be integrated in a single microcontroller, or each of them can be made in an independent microcontroller. Preferably, the system of the invention further comprises means for providing the geographic coordinates of the system.

According to a preferred embodiment, the system comprises memory means for storing historical data, such as for example: daily solar charge, duration in night hours, total power absorbed every day, total power consumed by the luminaires every day, energy in the batteries before and after charging, duration of consumption, and because said predictive algorithm is adapted to calculate the power to be delivered, also based on historical values for said day and said time.

Preferably, the two microcontrollers will have continuous communication with each other for the exchange of variables.

In accordance with another preferred embodiment, means are provided to gradually decrease the light intensity as the battery discharge occurs, by decreasing voltage, to allow the luminaire to never turn off during operation.

According to another feature of the system of the present invention, this comprises GPRS communication means. According to another preferred embodiment of the invention, the system comprises a presence sensor, to cause a temporary increase in the luminous intensity of the luminaires.

The system of the invention may comprise communication ports, such as Bluetooth®, wired RS232, Ethernet®, GPRS, etc., for data downloading or for entering data for programming control features.

Radiofrequency synchronization means of a luminaire with other similar luminaires are provided.

Preferably, the luminaires are LED luminaires whose light intensity is regulated by pulse width modulation (PWM). However, the technical principles and rules of the present invention can also be applied in consumptions other than luminaires, for example irrigation controls, small engines, traffic camera systems, etc. Brief description of the drawings

Next, it will make the detailed description of a preferred, but not exclusive, embodiment of the system of the present invention, for whose better understanding it accompanies some drawings, given merely by way of non-limiting illustrative example, in which: Fig. 1 is a characteristic curve lV of a standard photovoltaic solar panel; Fig. 2 is a block diagram of the system architecture of the present invention; Fig. 3 is an illustrative graph of the light flow as a function of time for when a presence or movement sensor is activated, in the case of a luminaire; Fig. is a graph illustrating the programming of the time of the luminous flux for different battery charge levels, also in the case of a luminaire; and Fig. 5 is a perspective view showing a device housing the systems of the present invention in a housing, and illustrating the different connections to the luminaire, solar panels, battery, other consumptions and ports I / O for communications and peripherals.

Description of embodiments of the invention

The objective of the present invention is to provide a microcontroller management system 100 integrated in a PV 1 luminaire, regulated by PWM (pulse width modulation). The system 100 will be responsible for managing the ignition and instantaneous power in the LED luminaire 1 and its luminous level. Other LED consumption 7 can also be managed, for example signaling or indication. The system will determine the nighttime hours and act accordingly to carry out proper power-up management. The luminaires 1 are powered by an autonomous solar energy system based on photovoltaic solar panels 2 that charge a 12 / 24V battery 3, which in turn feeds the luminaires 1.

The system includes:

- a first microcontroller 4 with an MPPT algorithm of the current efficiency type, which allows the maximum power from the solar panels 2 to be stored at battery 3 at all times,

- means for providing the geographical coordinates of the system 100, which can be pre-programmed at the factory or by GPS or an equivalent positioning system,

- memory means 6 for storing historical data, for example a programmable double erasable EEPROM memory. The data can be: daily solar charge, duration at night, total power absorbed every day, total power consumed by the luminaires every day, battery power 3 before and after charging, duration of consumption, etc,

- a second microcontroller 5 equipped with data inputs on the state of charge of the battery 3, and provided with a predictive algorithm that calculates the power to be delivered from the battery 3 to the luminaire 1, based on the day of the year and the time , of the historical values for said day and said hour, of the geographical coordinates, and of the state of charge of the battery 3.

In Fig. 2 the block diagram of the system 100 can be seen. The first microcontroller 4 is connected to the solar panels 2, through a charge shunt 21, and with the battery 3 by means of an outlet 31 The microcontroller 4 manages the energy supply to the battery by means of an MPPT algorithm of current efficiency. The second microcontroller 5, which contains the predictive algorithm for the management of the power supply of the luminaire 1 (battery discharge), is communicated with the luminaire 1 and the battery 3. One of the central points of the algorithm is the ability to decrease Gradually the light intensity in the luminaire 1 as the discharge of the battery 3 occurs, by means of a decrease in voltage, to allow the luminaire 1 to never turn off during operation (see Fig. 4). The system 100 comprises a series of I / O 8 and communication ports, such as Bluetooth, wired RS232, Ethernet, GPRS, etc., for data downloading or for data entry and for programming control features.

There are 5 variables for the calculation of the predictive algorithm: 1- Geographic Coordinates

With the geographical coordinates of the location of the device, it can be predicted that the average radiation will have throughout the year, from the historical data available in the Nasa database. 2- Current Date

With the current date (recovered from the internal clock of the second microcontroller 5) and the data of the previous point, the energy obtainable by day with the solar panels and therefore the energy that can be consumed during the night can be known.

3- Historical Accumulated

The system generates its own table of historical values to supply the calculation database. These parameters are: daily solar charge, the value of the battery before and after charging Energy consumption, consumption duration, etc.

4- Current Battery Status The state of the battery 3, at all times is important in case there are days when solar radiation does not reach the averages, either due to inclement weather or other causes. This data allows to protect the battery 3, which is the most delicate point of the installation to avoid a discharge that leaves the system 100 without supply.

5- Radiated power in solar panels

The radiated power in solar panels 2 is an instantaneous power variable in time and depends on the existing solar radiation. The algorithm follows that variation to obtain maximum load power.

The basic operation is as follows. The process begins to demand current from solar panel 2 and is increasing. Upon reaching its maximum point, the solar panel 2 lowers the voltage and the algorithm detects it and stops increasing the current request. When radiation variations occur (for example when passing a cloud over) the system 100 reduces the current request to maintain the maximum power point (MPPT, "Maximum PowerPoint Tracking '). See Fig. 1

With these variables two blocks of calculations are made: the calculation of battery charge and the calculation of discharge (or consumption). The charge acts on the MPPT microcontroller 4 of the solar panels 2 and allows to increase the charging efficiency of the battery 3 by 30% compared to traditional constant current methods. For the calculation of discharge or consumption, the fall of the system is anticipated as the consumption is not extreme at times when the load does not meet the established forecasts. The calculation of the discharge or consumption acts on the luminaire microcontroller 5, which executes the predictive algorithm.

Each calculation block acts on an independent microcontroller to make the instant calculation more powerful. Among the microcontrollers there is a continuous communication of variable exchange. The sum of these two blocks allows to achieve a system that guarantees the maximum possible energy efficiency. The operation of the predictive algorithm executed in the second microcontroller is explained below:

This algorithm is broken down into two sequential steps:

1. Calculation of instant consumption

2. Distribution of cargo overnight

1. Calculation of instant consumption

Explanation of variables:

MCP (Maximum consumption allowed): It is determined from the average radiation of the place where the system is located. It is measured as a percentage having a range from 10% to 25%.

EBH (Historic Battery Status). It is the average state of charge of the battery in the previous 5 days. It is determined just before nightfall. It is measured in percentage having a range from 40% to 100%

Cl (Instant consumption). It is determined from the variation that the state of charge of the battery has suffered at the end of the day compared to EBH. It is measured in percentage having a range that goes from 5% to MCP.

Calculation example 1

Thus, for example if the system has the following variables:

- Cl = 13% (13% of the battery charge will be consumed at night)

- MCP = 22%: (that at most 22% of the battery charge can be consumed)

- EBH = 80% (the battery is charged up to 80% of its capacity) In these conditions,

- If the battery goes from 80% to 75% the Cl decreases by 1% to 12%

- If the battery goes from 80% to 85%, the Cl is maintained at 13%. If for 4 days in a row, the battery increases its state of charge, the Cl increases by

0.4% going to 13.4%.

Calculation example 1 Thus, for example if the system has the following variables:

- Cl = 22% (22% of the battery charge will be consumed at night)

- MCP = 22% (which at most can consume 22% of the battery charge)

- EBH = 80% (the battery is charged up to 80% of its capacity)

In these conditions,

-If the battery goes from 80% to 75% the Cl decreases by 1% going to 21%

-If the battery goes from 80% to 85%, the Cl is maintained at 22%. If, for 4 days in a row, the battery increases its status, Cl cannot be increased since it has reached the maximum allowed MCP.

Thus, the battery consumption is set from the duration of the night.

In summer you can consume up to 25% of the battery capacity daily, while in winter up to 10% of its capacity.

With these upper limits, the consumption will be determined by the current state of the battery with respect to the last 5 days and its trend. This gives the parameter called Instant Consumption (Cl) that depends on the historical capacity of the battery. 2. Distribution of cargo overnight

Once Cl is known, it is determined how this load is distributed throughout the night. Initially, the luminaire is given maximum light power (for two hours if possible) to gradually reduce it. A case in which the maximum illumination flux is maintained for 1 hour for a 15% battery charge, 2 hours for a 30% battery charge, 3 hours for a battery charge is illustrated in Fig. 4 45% battery, and so on until maintaining 6 h for a 90% charge. Subsequently, the illumination of the LED luminaire (or the discharge of the battery) decreases gradually, except in the case of battery charging, it is maintained at 100%.

The dynamic algorithmic programming criteria can be the following

Example - 1 (summer):

Cl = 20%

The battery charge is 80% (EBH = 80%)

With a 210Ah Battery (Total Battery Capacity CTB = 210) With a load that consumes 4A (IL Load Intensity = 4A)

With a night that lasts 10h

If CF is the Final Consumption, then the consumption curve will be: CF = Cl * EBH * CTB = 20% * 80% * 210A = 33.6A The first 2 hours 4Ah of consumption (100%) 33.6A - 4A * 2 = 25.6A Divided into 8h => 25.6A / 8h = 3.2A The remaining 8: 3.2A consumption (80%) Example - 2 (winter)

Cl = 12%

The battery charge is 70% (EBH = 70%)

With a 210Ah Battery (Total Battery Capacity CTB = 210)

With a load that consumes 4A (IL Load Intensity = 4A)

With a night that lasts 14h

The consumption curve will be:

The final consumption is (CF):

CF = Cl * EBH * CTB = 12% * 70% * 21 OA = 17.64A The first 2 hours 2.8Ah of consumption (70%) 17.64A - 2.8A * 2 = 12.04A Divided into 12h => 12 , 04A / 12h = 1A

The remaining 12: 1A of consumption (25%)

The system may comprise a presence sensor (PRESENCE SENSOR in Fig. 2), movement or noise, to cause "requests" to temporarily increase the flux (light intensity) of the luminaires 1, interrupting the previous algorithm momentarily and returning to its execution after a certain period of time. See Fig. 3, in which some of these requests are exemplified. In this way, this algorithmic allows to decrease the light intensity in percentage as the battery is discharged (voltage decrease) to allow the luminaire to never turn off during operation. The system of the invention allows to manage and prolong the life of the batteries by reducing the number of charge and discharge cycles by means of the previous dynamic programming in operating hours. The system "compacts" the functions of regulation of charge / discharge of batteries and regulation of the light intensity in a single electronic device.

This union of both functions allows the rapid implementation of fully autonomous automatisms (luminaires, irrigation, autonomous controls, ...). The integration of a mini computer allows the rapid programming and adaptation of any equipment to your requirements.

In addition, all this allows the devices of the system of the invention to be present integrated in an aluminum tight housing 10, with a high level of tightness and rigidity. No electrical protection panel is required, as the system is wired inside the housing 10.

There is the possibility of connecting an external AC / DC 81 power supply in order to charge the battery from the mains at minimum load times. So that the external power supply does not consume anything while the photovoltaic system is operating, the control unit will control the source ignition by means of a relay. If the battery's charge capacity is compromised, the system will activate the source allowing the battery to be charged through the network. Once charged, the system will disconnect the source returning to its autonomous photovoltaic state. Although this is outside the scope of the invention. The system will have two NTC temperature probes: a first probe 31 in the battery (NTC1 TE P_BAT PROBE in Fig. 2) and a second probe in the electronic device board (NTC2 TE P_PLACA PROBE in Fig. 2) integrated in the I / O 8. The first temperature probe NTC 31 of the battery will allow to adapt the charging voltage to the temperature variation, guaranteeing optimal use of the battery.

The COMMS output / input allows you to connect different external wireless connection modules such as Bluetooth, RS232 cable, Ethernet or GPRS for data download or for programming control features.

A radio frequency electronics to synchronize the different luminaires through transceivers to connect and disconnect. It will also have switches for the configuration of the "master" and all slaves that will be assigned an identification number.

The electronic components of the board will be chosen in extended temperature range. A "switch of 8" allows you to select the capacity of the batteries measured in amps (A), in addition to being able to select whether a presence sensor is desired or not, and select other operating modes (possible extension).

An entry is planned to integrate presence or movement sensors. If you have presence sensors, there will be another mode of operation adapted to the lighting needs specified for each application. The device allows customization of the application.

In addition, an optional input (OPTIONAL INPUT, in Fig. 2) is also provided in the I / O block 8, in order to add optional components (expansion bus).

In the aforementioned EEPROM memory, the data obtained during the day is stored through the monitoring or monitoring system, as explained more above. The data saved through this monitoring or monitoring system can be downloaded to analyze the operation and have a history of the equipment. In future revisions of the project, the download can be accessed remotely via GPRS or other communication channels.

A signaling or indication LED 7 installed on one of the faces of the waterproof housing 10 (Fig. 5) and powered by a "shunt" 71 are used to give different information of a light type.

Describing sufficiently the nature of the present invention, it is noted that whatever does not alter its principle is within the scope of protection of the claims. In this sense, one skilled in the art will understand that LED luminaires could be replaced by other similar or equivalent consumptions, such as for example:

- irrigation systems,

- stand-alone laptops,

- wastewater purification systems using reverse osmosis, - autonomous traffic chambers,

- small engines or pumps, etc.

Likewise, solar panels could be replaced by wind turbines or wind turbines, these being also included in the scope of the invention as long as their principles can be applied.

Claims

1.- System for power management in luminaires (1) powered by an autonomous system of photovoltaic solar energy with photovoltaic solar panels (2) that charge a battery (3), which feeds the luminaires (1), characterized in that the system (100) integrates:

- first computing means, equipped with an MPPT algorithm, which allows the maximum power from the solar panels (2) to be stored in the battery (3), and

- second computing means, provided with data inputs on the state of charge of the battery (3), and a predictive algorithm that calculates the power to be delivered from the battery (3) to the luminaire (1), depending on of at least one of the following data: day of the year and time, geographic coordinates, and battery charge status (3).

2 - System according to claim 1, characterized in that said first computing means are constituted in a first microcontroller (4), and said second computing means is constituted in a second microcontroller (5).

3. - System according to claim 1, characterized in that said first computing means and said second computing means are integrated in a single microcontroller.

4. - System according to claim 1, characterized in that it comprises means for providing the geographical coordinates of the system (100).

5. System according to claim 1, characterized in that it further comprises memory means (6) for storing historical data, such as for example: daily solar charge, duration at night, total power absorbed each day, total power consumed by the luminaire (1) every day, energy in the battery (3) before and after charging, duration of consumption, and because said predictive algorithm is adapted to calculate the power to be delivered, also based on historical values for said day and said time.

6. System according to claim 2, characterized in that the two microcontrollers (4, 5) have a continuous communication for the exchange of variables.

7. - System according to claim 1, characterized in that it comprises means to gradually decrease the light intensity as the discharge of the battery (3) occurs, by means of voltage reduction, to allow the luminaire (1) to never turn off during its operation.

8. - System according to claim 1, characterized in that it comprises GPRS communication means.

9. - System according to claim 1, characterized in that it comprises a presence sensor, to cause a temporary increase in the luminous intensity of the luminaire (1).

10. - System according to claim 1, characterized in that it comprises communication ports, such as Bluetooth, wired RS232, Ethernet, GPRS, etc., for downloading data or for entering data for programming control features.

11. - System according to any one of the preceding claims, characterized in that it comprises means for radiofrequency synchronization of a luminaire (1) with other similar luminaires.

12. System according to any one of the preceding claims, characterized in that the luminaire (1) is a LED luminaire whose light intensity is regulated by pulse width modulation (PWM).