Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
  • H10F77/00—Constructional details of devices covered by this subclass
  • H10F77/95—Circuit arrangements
  • H10F77/953—Circuit arrangements for devices having potential barriers
  • H10F77/955—Circuit arrangements for devices having potential barriers for photovoltaic devices
• • 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
  • H02J1/00—Circuit arrangements for DC mains or DC distribution networks
• • 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
• • 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
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S323/00—Electricity: power supply or regulation systems
  • Y10S323/906—Solar cell systems

Definitions

• the field of the charging device is that of low-voltage accumulators for which there are commonly photovoltaic panels with direct connection, that is to say comprising an internal series of cells (or elementary photocells) îiuffisanl.e to obtain, under solar exposure, a no-load voltage of the panel higher than the voltage! of the accumulator, and therefore directly allowing the charging of the accumulator by its electrical connection to the panel.
• the invention relates to devices of the photo-v ⁇ lta ⁇ que type, intended to satisfy the charge of an electric accumulator under very variable lighting circumstances.
• the devices using a method according to the invention lend themselves to charging the accumulator when the available illumination decreases in proportion to its nominal value.
• the invention applies not only to electrochemical accumulators, but also to the charging of elements accumulating electrical energy in electrostatic form (with or without polarization), such as capacitors or super capacitors.
• This patent describes in particular how to optimize the power so as to directly supply a motor, without even passing through an accumulator.
• the converter structure is that of a conventional elevator, ilnais cel iii-ci explicitly plays the role of power amplifier, not voltage, as shown in Figure 1 and claimed.
• the goal is to automatically decrease the power called by the load if the available power of the panel decreases: it is again an adaptation system, type MPPT.
• This patent provides for using several amplifiers, each operating at variable frequencies, to balance the voltages of the output of panels placed in parallel.
• a photovoltaic panel of given surface intended for the charge of low voltage electric energy accumulator is characterized in that the internal structure of the panel is defined so as to deliver, under a given illumination, a short intensity circuit as high as possible as long as the elbow voltage of the panel or at least its voltage there empty remains greater than the operating threshold of a step-up converter interposed between said panel and said accumulator.
• I is characterized in that a minimum number of elementary cells in series is connected between the two terminals of the photovoltaic panel, this minimum number i being defined so that, under a given illumination, the elbow voltage of the photovoltaic panel is higher than the operating threshold voltage of the converter.
• the minimum number of elementary cells connected in series can be defined so that, under a given illumination, the open circuit voltage of the photovoltaic panel is higher than the threshold operating voltage of the converter.
• a device comprising a low voltage, a step-up converter, a photovoltaic panel comprising elementary photovoltaic cells and intended for charging the accumulator via
• I j the converter, characterized in that the connection of the elementary cells of said panel is essentially parallel, the serial connections being limited to what is necessary to obtain a panel bend voltage or a no-load voltage of the panel which is greater than the operating threshold voltage of the converter.
• the step-up converter uses a constant frequency and / or duty cycle. Note that the converter has active operating periods and inactive periods, which inactive periods are used to charge using the panel, a storage capacitor disposed upstream of the converter.
• the converter includes an oscillator with an input inhibiting the operation of the converter if the voltage on this input becomes less than a given threshold voltage, e 1t may well then! s inhibited as long as this voltage has not recovered a value greater than the threshold voltage.
• the electrical energy accumulator is of the electrochemical type, or of the capacitor or super capacitor type.
• FIG. 3 is a graphic representation of the load curve of a traditional device and of the device according to the invention.
• FIG. 4 is a schematic view of the charging device according to the invention and in particular of its step-up converter.
• FIG. 5 illustrates the operation, and displays the conduction times of the converter switch.
• FIG. 1 represents a traditional charging device (12) for ensuring the charging of an accumulator (11) of nominal voltage (UA), said device being of the type with photovoltaic panel, comprising a configuration of the elementary cells giving a voltage unladen (UB) i greater than the nominal voltage (UA) of the accumulator, and this for nominal illumination (WR).
• UAV voltage unladen
• WR nominal illumination
• this converter (24) has at least one mode of intermittently, associated with an upstream storage element (the electric heater).
• a conventional device for charging a nominal voltage accumulator (UA) leads to choosing a panel such that the current / voltage charge curve (I / U) has a no-load voltage (UB) greater than the nominal voltage (UA) of the accumulator, as shown schematically in Figure 3, by the curve (31).
• the operating point is chosen, in the prior art, such that the nominal voltage (UA) of the accumulator, corresponds to the elbow ( 32) of the curve (31).
• the invention recommends, for
• I I the same surface of the photovoltaic panel, to favor the value of i j the maximum intensity (I max) of the short-circuit current, to the detriment of the
• the four ; panel cell groups are now arranged in parallel: the panel output voltage is four times lower, therefore lower than the nominal voltage of the accumulator, but the maximum current that the panel can supply has become four times greater.
• the invention does not specifically seek to follow the point (34) of maximum power, but will preferentially use the range (35) in which the panel behaves as a current generator.
• the multiplying coefficient (N) can take a value (not necessarily an integer) as large as possible. There is however a technological limitation: it is imperative that the no-load voltage of the
• the invention favors the paralleling of the elementary cells of a panel of given surface (S).
• the design according to the invention amounts to using a] photovoltaic lap having only cells in parallel for a given total surface.
• the converter production technology should therefore have a minimum operating voltage (UC) lower than the elbow voltage or at least the no-load voltage of an elementary cell of the photovoltaic panel.
• the dimensioning of the panel according to the invention will simply have to limit i the number of series connections of cell groupings, to what is necessary for obtaining an elbow tension. of the panel, or at least no-load voltage (UB2), which is greater than the operating threshold
• this J onction threshold is of the order of 1 volt.
• j For an elbow voltage of the elementary cells equal to 0.5 volts, we will take for example a panel whose surface is divided into three groupings in series, by inserting such a step-up converter taken with a multiplying coefficient of 10 to apply the invention charged by a 12 volt accumulator. According to the prior art, the panel surface would have been divided into at least 24 groups connected in series.
• the above principles are retained in the case where it is necessary to charge a capacitor rather than an electrochemical accumulator.
• the voltage (UA) previously defined as the nominal voltage of the accumulator will this time be defined either as i charge stop voltage of the capacitor, or as mean value of a charge voltage in an operation tolerating a small excursion of on either side of this value.
• the step-up converter (24) here comprises an inductor (43), a switch (44) controlled by an oscillator (45) whose duty cycle defines the voltage rise, and operating for example at constant frequency i, and finally a diode (46) connected to the accumulator. Any other lifting structure known to those skilled in the art would also be suitable.
• Linear's LT1613 circuit which performs all of the booster and oscillator functions, naturally stops working if its voltage drops below about 0.99 volts, and resumes for a
• the assembly with diode and input capacitor is known to those skilled in the art, this assembly avoiding directly stressing the panel when the switch is turned on.
• FIG. 5 illustrates such an operation, by visualizing the conduction times of the switch.
• the diode (47) is not used, so as to avoid an additional voltage drop.
• i use can also be made of a muting input
• the duty cycle of the converter can be chosen to be variable so as to optimize the conduction time of the switch (44) in the

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)
• Dc-Dc Converters (AREA)
• Air Bags (AREA)

Priority Applications (4)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26213160

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (82)

Citations (1)

Family Cites Families (7)

• 2002
  • 2002-05-03 FR FR0205656A patent/FR2832870B1/fr not_active Expired - Fee Related
  • 2002-08-08 JP JP2003522240A patent/JP2005500792A/ja active Pending
  • 2002-08-08 WO PCT/IB2002/003161 patent/WO2003017446A1/fr not_active Ceased
  • 2002-08-08 AT AT02755440T patent/ATE410812T1/de not_active IP Right Cessation
  • 2002-08-08 EP EP02755440A patent/EP1417741B1/fr not_active Expired - Lifetime
  • 2002-08-08 DE DE60229265T patent/DE60229265D1/de not_active Expired - Lifetime
  • 2002-08-08 US US10/486,007 patent/US7030597B2/en not_active Expired - Fee Related

Patent Citations (1)

Non-Patent Citations (3)

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