Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
  • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
  • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

• the present invention relates to an optimized operating method of an autonomous system comprising a photovoltaic generator.
• photovoltaic solar energy is an inexhaustible source of energy, it is however weakened by screens, such as clouds, lying on the path of photons emitted by the sun to the solar modules.
• screens such as clouds
• MPPT Maximum Power Point Tracker
• an autonomous system comprising a source of photovoltaic energy generally comprises an energy storage means such as a battery.
• an energy storage means such as a battery.
• a DC / DC converter that reduces the voltage and raises the current, can be integrated in the autonomous system to adapt the characteristics of the photovoltaic panel to the characteristics of the battery.
• a BMS (Battery Management System) device can be associated in addition to the system. The device makes it possible to limit the current, thus leading to a loss of power. The use of a BMS device in combination with a DC / DC converter is then counterproductive, from an optimization point of view of the energy produced by the photovoltaic generator.
• patent application US 2010/0066309 discloses a mode of management of the charge of a battery by an intermittent source, through a super-capacitor. This mode of charge management aims primarily to limit the charging current, and does not optimize the solar energy not stored in the battery.
• the patent application US 2010/0231162 discloses a device for charging and discharging a battery comprising a plurality of cells. The cells are connected in series during the discharge. When the temperature of one of the cells reaches a maximum allowable temperature, it is disconnected from the battery.
• EP 2282392 discloses a device comprising a battery, a charge controller of said battery and a photovoltaic generator, connected in series. The charge controller has a bypass circuit controlled by a control circuit.
• EP 2200152 discloses a photovoltaic system comprising a photovoltaic generator and a backup voltage generator. The system includes a switch for either connecting the voltage generator in series with the photovoltaic generator or disconnecting it.
• a first switch system arranged to disconnect the secondary load from the main load
• the method further comprises the following steps:
• the measurement step including the measurement of the voltage at empty at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator;
• the measuring step comprises measuring the output current intensity of the photovoltaic generator, and the first threshold value comprises a predetermined threshold current intensity.
• the first switch system is in a first state so that the photovoltaic generator supplies the primary load and then the secondary load in series when the result of the comparison shows that the no-load voltage at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator is greater than the first threshold voltage.
• the first switch system is in a second state, opposite to the first state, so as to disconnect the secondary load from the main load when the result of the comparison step shows that the no-load voltage at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator is lower than the first threshold voltage.
• the primary charge comprises a first battery
• the secondary charge comprises a thermal device configured to heat or cool the first battery and / or the photovoltaic generator.
• the measurement step may comprise measuring the no-load voltage at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator, and the threshold voltage corresponds to the sum of the minimum voltage of the photovoltaic generator.
• the threshold voltage corresponds to the sum of the minimum voltage of the photovoltaic generator.
• a second switch system is arranged to disconnect the primary load from the main load. The first switch system and the second switch system can be operated according to the result of the comparison step.
• the measuring step comprises measuring the no-load voltage at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator, and the first threshold value comprises a threshold voltage corresponding to the voltage minimum operation of the primary load.
• the measured electrical quantity is compared with a second threshold voltage corresponding to the minimum operating voltage of the secondary load (30).
• the first and second switch systems are operated so as to disconnect the primary load from the main load, so that the photovoltaic generator supplies only the secondary load when the result of the comparison step shows that the no-load voltage at the terminals of the photovoltaic generator or the voltage of the maximum power produced at the terminals of the photovoltaic generator is between the second and first threshold voltages.
• FIG. 1 - Figures 1, 3 and 4 show, schematically, an autonomous system according to one embodiment of the invention
• - Figures 2a and 2b show, schematically, a switch system included in the autonomous system according to another embodiment of the invention.
• the aim is to optimize the use of the power produced by a photovoltaic generator of an autonomous system, by providing an operating method taking advantage of the excess power available beyond the supply of a primary primary load, in order to feed a secondary load.
• the autonomous system 10 comprises at least one photovoltaic generator 1 1 arranged to feed a main load 12.
• autonomous system is meant a system capable of providing independent of its administration and its energy supply.
• the photovoltaic generator 1 1 preferably comprises at least one panel provided with photovoltaic solar cells.
• the autonomous system 10 comprises two essential elements, the main load 12 and the photovoltaic generator 11.
• the main load 12 is connected to the photovoltaic generator 1 1 by its output terminals B and D.
• the current flows inside the load 12 from a first terminal (B or D) to a second terminal (D or B).
• Each of its two elements (1 1 and 12) may include one or more devices.
• the photovoltaic generator 1 1, upstream of the output terminals B and D, may comprise an MPPT device, a DC / DC converter, etc.
• the photovoltaic generator 1 1 is devoid of DC / DC converters.
• the main load 12 includes a primary load 20 connected in series with a secondary load 30.
• the primary load 20 is connected between the terminals B and C and the secondary load 30 is connected between the terminals C and D.
• Each of the loads, primary 20 and secondary 30, is configured to include one or more electrical devices.
• the primary 20 and secondary 30 charges are distinct elements and can not be assimilated to cells belonging to a battery.
• electrical device is meant any device requiring a supply of electrical energy to perform a specific function.
• the electrical device may be a floor lamp, a roller shutter, a parking meter, a battery, a fan, etc.
• the primary load 20 comprises the main device or devices of the autonomous system 10.
• the autonomous system 10 gives priority to the supply of the primary load 20 and its electrical devices, with respect to the secondary load 30 and its electrical devices.
• the autonomous system advantageously comprises a management device 40 comprising a first switch system 31, controlled by the management device 40 via integrated control means (not shown ).
• the first switch system 31 is arranged to disconnect or connect the secondary load 30 of the main load 12.
• the switch system 31 may have at least first E1 0 and second E1 cc states.
• the first switch 31 is configured to be in the first state E1 0 so as to leave the secondary load 30 connected in series with the primary load 20 within the main load 12.
• the first switch 31 is in the first state E1 0 so that the photovoltaic generator 1 1 supplies the primary load 20 and the secondary load 30 in series.
• the first switch system 31 is also configured to be in the second state E1 cc so as to disconnect the secondary feed 30 of the main charge 12, in other words, the PV generator 1 1 does feeds between its output terminals B and D, that the main load 20.
• the switch system 31 comprises a first switch 31 connected in parallel with the secondary load 30.
• the first switch 31 bypasses the secondary load 30
• the current generated by the generator 1 1 travels only the main charge 20.
• the secondary charge 30 remains connected in series with the primary charge 20.
• the photovoltaic generator 1 1 can supply, and the primary charge 20 and secondary charge 30.
• the switch system may advantageously include several switches so as to disconnect the secondary load 30 while avoiding short-circuiting.
• the switch system 31 may comprise a second switch 31b, mounted between the secondary load 30 and one of the terminals C and D.
• the first switch 31a is mounted between the terminals C and D, in parallel with the branch comprising the secondary load 30 and the second switch 31 b.
• the first switch system 31 is in the first state E1 0 , when the first switch 31a is open and the second switch 31b is closed.
• the first switch system 31 has the second state E1 cc, when the first switch 31a is closed and the second switch 31b is opened.
• the two switches 31a and 31b are advantageously in opposite states.
• the switch system 31 may comprise an electronic switch, for example a transistor, or a mechanical switch for example an electromechanical microsystem (MEMS).
• an electronic switch for example a transistor
• a mechanical switch for example an electromechanical microsystem (MEMS).
• MEMS electromechanical microsystem
• first switch system 31 Here we have given two examples of execution of the first switch system 31. However, those skilled in the art may also use other configurations depending on the devices included in the secondary load 30, so as to have two states of the switch system 31: a first state in which the generator 1 1 feeds both the primary charge 20 and the secondary charge 30, and a second state in which the secondary charge 30 is disconnected from the main charge 12 so that the generator 1 1 feeds only the primary charge 20.
• the operating method of the autonomous system 10 comprises at least one step of measuring an electrical quantity A m .
• the measuring step is performed by a measuring device 42, preferably integrated in the management device 40.
• the measuring device 42 is configured to measure at least one electrical quantity, for example a voltage or a current intensity.
• the measurement device 42 may comprise one or more conventional systems, such as a digital voltmeter, for measuring the voltage at the terminals of an element of the autonomous system 10, or such as a digital ammeter, a shunt, or a current transformer for measuring the intensity of current flowing in an element of the autonomous system 10.
• the measuring device 42 comprises one or more sensors for measuring voltage and / or intensity continuously and / or periodically.
• the choice of the conventional measurement system or systems is determined by the skilled person according to the elements included in the autonomous system 10, and the measurement accuracy envisaged.
• the measured electrical quantity A m is chosen from the following electrical quantities:
• a voltage A at the terminals of the photovoltaic generator 1 1, in other words a voltage between the terminals B and D;
• the method further comprises a step of comparing the latter. Indeed, the measured quantity A m is compared with a first threshold value A s i.
• the first threshold value A s i is chosen as a function of the measured quantity A m , so that the comparison result can provide information on the capacity of the photovoltaic generator 1 1 to be fed, the primary load only, or the primary charge 20 and the secondary charge 30 at the same time.
• the comparison step may be performed by a conventional computer integrated in the control means 41 of the management device 40.
• the computer 41 is configured, either to directly compare the magnitude measured A m with the first threshold value A s i, or to compare values representative of these quantities (A m , A s i).
• the management device 40 will operate the first switch system 31.
• the management device 40 will actuate the first switch system 31 so that the secondary load 30 remains connected in series with the primary load 20.
• the photovoltaic generator 1 1 by feeding the main load 12, will supply at the same time the primary charge 20 and the secondary charge 30.
• the management device 40 when the comparison result shows that the power of the photovoltaic generator 1 1 is insufficient to supply the primary load 20 and the secondary load 30 at the same time, the management device 40 will actuate the first switch system 31 so that to disconnect the secondary charge 30 from the main charge 12. As a result, the photovoltaic generator 1 1 by supplying the main charge 12, will supply only the primary charge 20.
• the measuring step comprises measuring the output current intensity lu of the photovoltaic generator 1 1.
• the read intensity measured can be, for example, the short-circuit current of the photovoltaic generator 1 1.
• the first threshold value A s i comprises a predetermined threshold current intensity Is. This threshold current intensity is predetermined according to the components included in the primary load 20, or depending on the components of the primary load 20 and the secondary charge 30. Moreover, in certain applications and / or certain configurations of the autonomous system 10, it is easier and more useful to measure a voltage and compare it to a threshold than to measure and compare a current intensity.
• the measuring step thus comprises the measurement of the open- circuit voltage U 0C v at the terminals of the photovoltaic generator 1 1, in other words, between the terminals B and D.
• the measured electrical quantity (A m , A) then corresponds to the open- circuit voltage U 0C v which is characteristic of the generator 1 1 and also depends on the sunlight conditions.
• the measuring step can also comprise the measurement of the voltage of the maximum output power UMPP at the terminals of the photovoltaic generator 1 1, otherwise said, between terminals B and D. This voltage of the maximum power UMPP is determined by the MPPT device.
• the step of comparing the measured quantity (U 0C v or UMPP) with the first threshold value A s i advantageously makes it possible to provide an indication of the capacity of the photovoltaic generator 1 1 to supply, in addition to the primary load 20, the secondary charge 30.
• the first switch system 31 is in the first state E1 0 when the result of the comparison shows that the voltage at the terminals of the photovoltaic generator (Un, U ocv ) or the voltage of the maximum power produced at the terminals of the photovoltaic generator (One, UMPP) is greater than the first threshold voltage A s i.
• the first electronic switch system 31 is in the second state E cc when the result of the comparison step shows that the no- load voltage at the terminals of the photovoltaic generator (Un, U ocv ) or the voltage of the maximum power produced at the terminals of the photovoltaic generator (Un, UMPP) is lower than the first threshold voltage A s i.
• the first threshold value A s i may comprise a threshold voltage corresponding to the minimum operating voltage U pr im of the primary load 20.
• This voltage U pr im is predetermined depending on the components included in the primary charge 20.
• the step of comparing U 0C v or UMPP with U pr im advantageously provides information if, after the supply of the priority devices of the main load 20, the energy produced by the generator 1 1 has a surplus of energy available.
• the latter can then be used to feed the secondary load 30.
• the secondary charge 30 may comprise an electronic device operating at low electrical energy, such as a device based on light-emitting diodes, for example a lamp, or an information display, etc.
• the secondary charge 30 may also include an electronic device operating in proportion to the amount of energy it receives, such as linear actuators, for example, an electromechanical actuator.
• the primary load 20 comprises a first battery 22 and the secondary load comprises a thermal device 32 configured to heat or cool the first battery 22 and / or the photovoltaic generator 1 1 (see Figure 3).
• the battery 22 is an electric accumulator, that is, an electrochemical system configured to store electrical energy. The system restores chemical energy into electrical energy, using electrochemical reactions.
• the battery 22 comprises a reversible electrochemical system, it can thus be rechargeable.
• the battery 22 is configured to be charged when connected to the photovoltaic generator 1 1.
• the battery 22 may be a lead-acid battery, an alkaline battery, or a lithium-based battery.
• the battery 22 is a lithium-ion type battery.
• the thermal device 32 comprises a fan 33 configured to cool the battery 22 and / or the photovoltaic generator 11.
• the power dissipated by the thermal device 32 is equivalent to or substantially equivalent to the power supplied by the photovoltaic generator 1 1.
• the combination of this type of fan 33 with a battery 22 makes it possible to take advantage of the surplus electrical power generated, especially when the solar panels receive a strong solar irradiation. More irradiation is important plus the rise in the temperature of the battery 22 and the temperature of the solar panels of the generator 1 1 is important.
• This configuration ensures efficient operation of the fan 33 with a faster and faster speed depending on the solar irradiation.
• the fan 33 advantageously makes it possible to lower the ambient temperature around the battery and / or the solar panels of the generator 1 1 by forced convection.
• the lowering of the temperature of the battery 22 allows an improvement in the charging operation, and the increase in its lifetime.
• the lowering of the temperature of the photovoltaic panels of the generator 1 1 by self-consumption ventilation allows advantageously an improvement in the energy recovery of the photovoltaic generator during strong solar irradiation.
• the combination of this type of fan 33 with a battery 22 allows a beneficial use of the surplus power produced during strong solar irradiation, improving the performance and reliability of the battery 22 and the photovoltaic generator 1 1, in other words of the autonomous system 10.
• the secondary charge 30, according to this embodiment may also include heating sheets 33 'configured to be associated with the battery 22.
• the carrier mobility decreases and the internal impedance increases within a battery, in particular a lithium-ion battery.
• the high current capacity of the battery 22 is limited.
• battery manufacturers generally prohibit recharging the battery if its temperature is below a preset temperature (at low temperatures), since charging the battery in these conditions may damage it.
• at low temperatures are meant temperatures below 0 ° C, and preferably below -10 ° C.
• the management device 40 or the thermal device 32 may comprise a measurement system (not shown in the figures) of the temperature of the battery 22.
• the measurement system is configured to provide information on the temperature of the battery 22. It can comprise a plurality of temperature sensors distributed in the battery 22, for example distributed over the surface of the battery 22.
• the temperature sensors may comprise a thermometer, a thermocouple, a thermistor, or any system making it possible to provide a measurement of the temperature.
• the management device 40 according to the result of the comparison and the measurement of the temperature of the battery 22, will operate either the fan 33 or the heating sheets 33 '.
• the threshold voltage A s i corresponds to the sum of the minimum operating voltage U pr im of the primary charge 20 and the minimum operating voltage U c of the secondary load 30
• the method is advantageously usable when the secondary charge 30 also comprises one or more electrical devices requiring a minimum supply of electrical energy to fulfill a certain function.
• the surplus power must be sufficient to operate the second load 30 for the management device actuates the first switch system 21, so that the photovoltaic generator 1 1 feeds both the primary load 20 and the secondary charge 30 connected in series with the latter.
• the autonomous system 10 comprises a second switch system 21 arranged to disconnect the primary load 20 from the main load 12.
• the operation of the second switch system 21 with the primary load 20 is similar to the operation of the first switch system 31 with the secondary load 30.
• the first switch system 31 and the second switch system 21 are controlled by the management device 40, and are operated according to the result of the comparison step.
• this configuration offers the management device 40 more possibilities for managing the electrical energy produced by the photovoltaic generator 1 1. It is advantageously possible to disconnect the primary load while leaving the secondary load connected.
• the primary and secondary loads 30 may both include a battery.
• the use of two switch systems 21 and 31 associated with the loads 20 and 30 makes it possible to charge the battery of the primary load 20 as a priority.
• the management device 40 can, if the power delivered is sufficient, charge in addition the battery of the secondary charge 30. If after the comparison step, it turns out that the power delivered by the photovoltaic generator 1 1 can only charge the battery of the primary charge 20, then the management device 40 will disconnect the secondary load 30.
• the management device 40 may advantageously switch to another state in which the primary charge 20 is disconnected, and the secondary charge 30 is connected to the main load 12, to recharge the battery of the secondary charge 30.
• the measuring step comprises measuring the no-load voltage at the terminals of the photovoltaic generator (Un, Uocv) or the voltage of the maximum power produced at the terminals of the photovoltaic generator (Un, UMPP).
• the first threshold value A s i comprises a threshold voltage corresponding to the minimum operating voltage U pr im of the primary load 20.
• the measured electrical quantity A m is compared with both the first threshold value A s i and at a second threshold value A S 2, corresponding to the minimum operating voltage U sec of the secondary load 30.
• the first 31 and second 21 switch systems are actuated so as to disconnect the primary load 20, so that the photovoltaic generator 1 1 feeds the secondary load 30 when the result of the comparison step shows that the no- load voltage at the terminals of the photovoltaic generator (Un, U ocv ) or the voltage of the maximum power produced At the terminals of the photovoltaic generator (A, UMPP) is between the second A S 2 and the first A s i th threshold voltages.
• the power delivered by the photovoltaic generator 1 1 is not sufficient for the normal operation of the primary load 20
• this embodiment advantageously makes it possible to take advantage of the power of the generator 1 1 to supply the secondary load 30 and to operate the electrical device or devices included in the secondary charge 30.
• the secondary load 30 may include a backup battery that can be connected to the devices of the primary charge 20.
• the backup battery When the backup battery is charged, it can be associated with the photovoltaic generator 1 1 to provide power of the primary charge, in the case where the generator 1 1 alone can not operate the devices of the primary charge 20 (for example in conditions of low sunlight).
• the current flowing in the main load 12 flows through the primary load 20 only, through the secondary load 30 only or through the primary and secondary loads 20 and 30 mounted in the main load. series.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)
• Secondary Cells (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=54066011

Family Applications (1)

Country Status (3)

Family Cites Families (4)

• 2015
  • 2015-05-25 FR FR1554670A patent/FR3036866B1/fr not_active Expired - Fee Related
• 2016
  • 2016-05-25 EP EP16726843.2A patent/EP3304683A1/de not_active Withdrawn
  • 2016-05-25 WO PCT/EP2016/061808 patent/WO2016189035A1/fr unknown

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