JP2011249598A - Photovoltaic power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a charging circuit or a protection circuit of an accumulator which composes a photovoltaic power generator.SOLUTION: The photovoltaic power generator comprises: a panel module 1 which is provided with at least a plurality of photovoltaic cells in series connection; a battery module 59 which is connected in parallel with the panel module and charged by output of the panel module; driving circuits 11, 15 which intermit the output of the battery module and supply to a rectifier circuit; and a control circuit 18 which controls the driving circuit that drives the rectifier circuit according to an output voltage of the rectifier circuit. The output voltage of the panel module in series connection is lower than an upper limit of a charging voltage in a lithium ion battery unit.

Description

  The present invention relates to a solar power generation device, and more particularly, to a solar power generation device capable of simplifying a protection circuit for a storage battery constituting the solar power generation device.

  The energy generated by the solar power generation panel is stored in a storage battery such as a lithium ion battery. In this case, a voltage higher than the voltage of one lithium ion battery cell is generated, and the lithium ion batteries connected in series at this voltage are charged (Patent Document 1).

In such a charging circuit, a voltage higher than the standard (upper limit voltage, for example, 4.2 V) may be applied between both electrodes of the lithium ion battery. Therefore, it is necessary to provide a complicated charging / discharging circuit, a protection circuit, or the like. Yes (Patent Document 2)
FIG. 8 is a diagram illustrating a conventional solar power generation device. In FIG. 8, 1 is a photovoltaic panel module, 2 to 8 are cells constituting the photovoltaic panel, 53 is a lithium ion battery cell, 50 is a voltage detection circuit for detecting the voltage of the lithium ion battery, 51 is a resistor, 52 is a switch element, 54 to 58 are lithium ion battery units including a protection circuit, 59 is a lithium ion battery module, 11 is a coil, 12 and 15 are power MOSFETs, 13 and 16 are parasitic diodes in the power MOSFET, and 14 and 17 Is a drive circuit, 18 is a control circuit, 60 is a rectifier circuit, 61 and 62 are diodes, 64 and 65 are detection resistors, 67 is a capacitor, and 66 is an output terminal.

  In FIG. 8, the photovoltaic power generation panel module 1 is configured by a series circuit of a plurality of cells constituting the photovoltaic power generation panel, and the lithium ion battery unit 54 includes a lithium ion battery cell 53, a voltage detection circuit 50, a resistor. 51 and a switch element 52. The lithium ion battery module 59 includes a plurality of lithium ion battery units 54 to 58, and the rectifier circuit 60 includes diodes 61 and 62 and a capacitor 67.

  In FIG. 8, the solar power generation panel generates a predetermined voltage determined by the intensity of sunlight when irradiated with sunlight. A general photovoltaic power generation panel generates a voltage of about 0.6 V at maximum. The photovoltaic power generation panel module 1 generates a predetermined voltage determined by the series number of cells constituting the photovoltaic power generation panel.

  When the power MOSFET 12 is on, the voltage generated in the photovoltaic panel module 1 is applied to the lithium ion battery module 59. Moreover, it applies to the lithium ion battery cell 53 in the lithium ion battery unit 54, and each lithium ion battery cell is charged.

  The voltage detection circuit 50 in the lithium ion battery unit 54 detects the voltage applied to the lithium ion battery cell 53 and transmits the detected voltage information to the control circuit 18. Similar operations are performed in the other lithium ion battery units 55 to 58 in the lithium ion battery module 59, and voltage information between the lithium ion battery electrodes is transmitted to the control circuit 18.

  The control circuit 18 monitors the voltage detected by the voltage detection circuit 50. When the detected voltage exceeds a predetermined value, the control circuit 18 turns off the power MOSFET 12 and stops charging the lithium ion battery 53.

  A series circuit including a resistor 51 and a switch element 52 connected in parallel with the lithium ion battery 53 adjusts the charging capacity of the lithium ion battery. For example, when the battery is overcharged as compared with other lithium ion batteries, the switch element 52 is turned on to lower the charge capacity and adjust the charge amount.

  The power MOSFET 15, the coil 11, and the rectifier circuit 60 constitute a chopper type booster circuit. Magnetic energy is stored in the coil 11 while the power MOSFET 15 is on, and the stored magnetic energy is transferred as boosted electrostatic energy to the capacitor 67 in the rectifier circuit 60 when the power MOSFET 15 is off.

  The control circuit 18 detects the output voltage Vout generated at both ends of the capacitor 67 via the resistors 64 and 65, and supplies the power MOSFET 15 to the power MOSFET 15 via the drive circuit 17 so that the output voltage Vout becomes a desired voltage. The waveform of the voltage V is controlled.

JP 2008-154334 A JP 2009-89488 A

  In the prior art, the voltage generated in the photovoltaic panel module 1 is applied to a plurality of serially connected lithium ion battery cells 53 in the lithium ion battery unit 54. That is, the voltage generated in the solar power generation panel module 1 is a voltage that is a multiple of the voltage of each lithium ion battery. When this voltage is not applied equally to the plurality of lithium ion batteries, each lithium ion battery is equal. Will not be charged. For this reason, in the lithium ion battery units 54 to 58 connected in series, it is necessary to provide a circuit for adjusting the charging rate of the cell including a voltage detection circuit, a resistor, and a switch element for each unit. For this reason, the number of circuit components increases and the cost increases.

  The present invention has been made in view of such problems, and in a photovoltaic power generation apparatus that charges a storage battery using a photovoltaic power generation panel, the charging circuit or protection circuit of the storage battery constituting the photovoltaic power generation apparatus is simplified. The solar power generation device which can do is provided.

  In order to solve the above problems, the present invention employs the following means.

  A panel module comprising at least a plurality of solar cells connected in series, a battery module connected in parallel to the panel module and charged by the output of the panel module, and a drive for intermittently supplying the output of the battery module to the rectifier circuit A control circuit that controls the drive circuit that drives the rectifier circuit according to the output voltage of the circuit and the rectifier circuit, and the output voltage of the panel module that is connected in series is less than or equal to the upper limit value of the charge voltage of a single battery is there.

  Since this invention is provided with the above structure, the charging circuit or protection circuit of the storage battery which comprises a solar power generation device can be simplified.

It is a figure which shows 1st Embodiment. It is a figure which shows 2nd Embodiment. It is a figure which shows 3rd Embodiment. It is a figure which shows 4th Embodiment. It is a figure which shows 5th Embodiment. It is a figure which shows 6th Embodiment. It is a figure which shows 7th Embodiment. It is a figure which shows the conventional solar power generation device.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, 1 is a photovoltaic panel module, 2 to 8 are photovoltaic panel cells, 59 is a lithium ion battery module, 9 is a lithium ion battery unit including a protection circuit, 10 is a lithium ion battery cell, 11 is Boosting coil, 12 and 15 are power MOSFETs, 13 and 16 are parasitic diodes in the power MOSFET, 14 and 17 are drive circuits, 18 is a control circuit, 19 is a rectifier circuit, 24 to 33 are diodes, and 40 and 41 are detections. The resistors 20 to 23 and 34 to 38 are capacitors, and 39 is an output terminal.

  In FIG. 1, a photovoltaic power generation panel module 1 includes a series circuit of cells that constitute a photovoltaic power generation panel. Further, the lithium ion battery module 59 is configured by a single lithium ion battery unit 9, and the lithium ion battery unit 9 is configured by using a single lithium ion battery cell 10.

  In FIG. 1, the rectifier circuit 19 includes diodes 24 to 33 and capacitors 20 to 23 and 34 to 38, and this rectifier circuit is called a multiple voltage rectifier circuit or a cock croft-Walton circuit. This circuit generates a voltage obtained by multiplying the voltage between both terminals of the capacitor 38 by an integer, and this voltage is output from the output terminal 39 as the output voltage Vout.

  The resistors 40 and 41 detect the output voltage Vout output from the output terminal 39, and this detected voltage is supplied to the control circuit 18.

  In the solar power generation device shown in FIG. 1, energy for charging the lithium ion battery module 59 is generated by the solar power generation panels 2 to 8.

  The maximum generated voltage per panel of the photovoltaic power generation panel module 1 is about 0.6V, and the generated voltage when seven panels are connected in series as shown in FIG. 1 is about 4.2V. As a result, the maximum voltage supplied to the lithium ion battery module 59 is also about 4.2V.

  That is, in the apparatus shown in FIG. 1, the voltage supplied to the lithium ion battery module is limited to about 4.2V. As a result, the voltage supplied to the lithium ion battery cell 10 can be suppressed within the upper limit value of the charging voltage of the lithium ion battery. That is, the energy obtained when seven photovoltaic power generation panels are connected in series can be stored in the lithium ion battery cell 10 without exceeding the upper limit value of the charging voltage of the lithium ion battery.

  For this reason, in a conventional charging device, a protection circuit required when lithium ion batteries are connected in series, that is, a circuit (resistor 51, switch element 52 in FIG. 8) or a circuit for reducing the voltage variation of the lithium ion battery or The voltage detection circuit 50 that detects the voltage of the lithium ion battery can be eliminated.

  In the circuit shown in FIG. 1, the drive circuit 14 and the power MOSFET 12 are turned on when the photovoltaic power generation panel module 1 is generating power, and supply a charging current to the lithium ion battery module 59. Moreover, when the photovoltaic power generation panel module 1 is not generating electric power, it is turned off to prevent backflow from the lithium ion battery module 59 to the photovoltaic power generation panel.

  The energy stored in the lithium ion battery module 59 is boosted by a booster circuit including the coil 11, the power MOSFET 15, and the drive circuit 17 and supplied to the rectifier circuit 19. The control circuit 18 variably controls, for example, the duty ratio of the MOSFET 15 of the drive circuit that drives the rectifier circuit 19 according to the output voltage Vout of the rectifier circuit 19 to control the output voltage Vout to a desired value.

  The rectifier circuit 19 shown in FIG. 1 is a multiple voltage rectifier circuit, and can generate a higher voltage than the rectifier circuit shown in FIG. For this reason, even when the voltage output from the lithium ion battery module 59 is low, the desired output voltage Vout can be output from the output terminal 39.

  Thus, according to the present embodiment, the circuit (resistor 51, switch element 52) that reduces the voltage variation of the lithium ion battery cell and the voltage detection circuit 50 that detects the voltage of the lithium ion battery cell can be deleted. It is possible to simplify the apparatus.

  FIG. 2 is a diagram showing a second embodiment of the present invention. In the example shown in FIG. 2, a multiple voltage rectifier circuit is used as the rectifier circuit 19, and lithium ion capacitors are used as the capacitors 34 to 38 constituting one capacitor row.

  Lithium ion capacitors have a larger capacity than electrolytic capacitors. Similarly, the voltage rating can be made higher than that of an electric double layer capacitor having a large capacity.

  The voltage rating of the lithium ion capacitor is about 3.8V, which is substantially equal to the output voltage (about 3.7V) from the single cell of the lithium ion battery. Further, by using a lithium ion capacitor as the capacitor of the multiple voltage rectifier circuit, the output voltage Vout can be further stabilized.

  In FIG. 2, reference numerals 70 to 74 denote voltage detection circuits, which detect voltages between both terminals of the lithium ion capacitors 34 to 38. Lithium ion capacitors may fail when a voltage exceeding the rating is applied. For this reason, in the apparatus shown in FIG. 2, the voltage detection circuits 70 to 74 monitor the voltage between both terminals of the lithium ion capacitor and provide a protective function by a method such as turning off the power MOSFET 15 when an abnormality occurs. .

  FIG. 3 is a diagram showing a third embodiment of the present invention. In the example shown in FIG. 3, similarly to the example shown in FIG. 2, a multiple voltage rectifier circuit is used as the rectifier circuit 19, and lithium ion capacitors are used as the capacitors 34 to 38 constituting one capacitor row. As the feedback voltage fed back to the control circuit 18, a voltage obtained by dividing the voltage generated at both ends of the capacitor 38 by the resistors 40 and 41 is used. As described above, in this embodiment, the voltage applied to one lithium ion capacitor is divided by the resistors 40 and 41, and the divided voltage is monitored. Thereby, the voltage applied per lithium ion capacitor can be monitored. Therefore, by controlling so that the voltage divided by the resistors 40 and 41 does not exceed a predetermined value, the voltage across the lithium ion capacitor can be controlled not to exceed a predetermined value. In this way, by controlling the voltage across the capacitor 38, the voltages of the capacitors 34 to 37 that generate the same voltage as the capacitor 38 can be controlled so as not to exceed a predetermined value. Thus, according to the third embodiment of the present invention, the voltage detection circuits 70 to 74 shown in FIG. 2 can be eliminated.

  FIG. 4 is a diagram showing a fourth embodiment of the present invention. In the example shown in FIG. 4, a switching circuit including a power MOSFET 44, a parasitic diode 44 in the power MOSFET, and a drive circuit 42 is used instead of the boosting coil 11 shown in FIG.

  In the apparatus shown in FIG. 4, a pulse voltage can be supplied to the rectifier circuit 19 by alternately turning on and off the power MOSFET 43 and the power MOSFET 15. The rectifier circuit 19 constitutes a multiple voltage rectifier circuit, and can output a voltage that is an integral multiple of the input voltage input to the rectifier circuit 19 as the output voltage Vout.

  In the apparatus of this embodiment, a circuit for supplying a feedback voltage to the control circuit 18 used in the apparatus shown in FIGS. Therefore, according to the present embodiment, the voltage generated by the lithium ion battery cell 10 can be converted into an output voltage Vout that is an integral multiple of the voltage generated by a simpler configuration.

  FIG. 5 is a diagram showing a fifth embodiment of the present invention. In the example shown in FIG. 5, a parallel connection body of a plurality of lithium ion battery cells 101 to 104 is used as the lithium ion battery module 59. In the example shown in FIG. 5, more charges can be stored by using a plurality of lithium ion battery cells connected in parallel. Even when a plurality of lithium ion battery cells are connected in parallel, the voltage applied to both ends of the lithium ion battery cell is about 4.2 V or less, which is the maximum voltage generated in the photovoltaic power generation module 1. Therefore, also in the example shown in FIG. 5, the circuit (resistor 51, switch element 52) for reducing the voltage variation of the lithium ion battery and the voltage detection circuit 50 of the lithium ion battery used in the conventional example are deleted. can do.

  FIG. 6 is a diagram showing a sixth embodiment of the present invention. The apparatus shown in FIG. 6 differs from the fifth embodiment shown in FIG. 5 in that current balance means (balancers) 105 to 108 are used. The current balance means shown in FIG. 5 adjusts so that the currents flowing through the lithium ion battery cells 101 to 104 are equal. As the current balancing means, a resistor, a coil, a semiconductor element, or the like can be used. In particular, by adjusting the parameters of the elements used as the current balance means, it is possible to reduce current imbalance caused by variations in the internal resistance of the lithium ion battery cells.

  According to this embodiment, even when lithium ion battery cells are connected in parallel, the current flowing through each lithium ion battery cell can be made evenly closer and the life of the lithium ion battery cell can be made longer by using current balancing means. Can do.

  FIG. 7 is a diagram showing a seventh embodiment of the present invention. In the circuit shown in FIG. 7, a plurality of photovoltaic power generation panels are connected in parallel, and each parallel circuit is connected in seven stages in series. For this reason, also in the apparatus shown in FIG. 7, the voltage output from the photovoltaic power generation panel module is about 4.2 V at the maximum. For this reason, as the lithium ion battery module 59, the series-parallel circuit of the lithium ion battery cells 101-104 and the current balance means 105-108 can be used similarly to the circuit shown in FIG. In the present embodiment, since a plurality of photovoltaic power generation panels are connected in parallel, the voltage output from the photovoltaic power generation panel module 1 even when the output voltage of one photovoltaic power generation panel drops due to leaves or the like.・ Current reduction can be minimized.

  As described above, according to the present embodiment, the voltage generated by the photovoltaic power generation panel is set to be lower than 4.2 V which is the upper limit value of the charging voltage of one lithium ion battery cell, That is, the photovoltaic power generation panel is set to 7 series or less (0.6 V × 7), and a booster circuit or a multiple voltage rectifier circuit is used for the power supply path for supplying power from the lithium ion battery to the load, and then the load is increased. To supply.

  For this reason, in normal operation, a voltage higher than the upper limit value of the charging voltage is not applied to the lithium ion battery. Therefore, it is possible to simplify a circuit for protecting the lithium ion battery from overvoltage, which is necessary when charging a circuit in which lithium ion batteries are connected in series.

1 Power generation panel module 2 to 8 cells 9 Battery unit 10 cells 11 Boosting coil 12 MOSFET
13 Parasitic diode 14 Drive circuit 15 MOSFET
DESCRIPTION OF SYMBOLS 16 Parasitic diode 17 Drive circuit 18 Control circuit 19 Rectifier circuit 20-23 Capacitor 24-33 Diode 34-38 Capacitor 39 Output terminal 40, 41 Detection resistance

Claims (7)

A panel module comprising at least a plurality of solar cells connected in series;
A battery module connected in parallel to the panel module and charged by the output of the panel module;
A drive circuit for intermittently supplying the output of the battery module to the rectifier circuit;
A control circuit that controls the drive circuit that drives the rectifier circuit according to the output voltage of the rectifier circuit;
An output voltage of the panel module formed by connecting a plurality of solar cells in series is equal to or lower than an upper limit value of a charging voltage of a single battery. In the solar power generation device according to claim 1,
The battery module is a battery module of a lithium ion battery that is not connected in series, and an output voltage of a panel module composed of a plurality of solar cells connected in series is equal to or lower than an upper limit value of a charging voltage of the battery module. Solar power generator. In the solar power generation device according to claim 1,
The rectifier circuit is a multiple voltage rectifier circuit using a lithium ion capacitor in one capacitor row, and includes a voltage detection circuit that monitors the voltage of the lithium ion capacitor and stops the drive circuit in the event of an abnormality. Solar power generator. In the solar power generation device according to claim 1,
The photovoltaic power generation apparatus according to claim 1, wherein the drive circuit is a boost circuit that includes a series connection circuit of a reactor and a switching circuit, and obtains a boost output from a connection point of the reactor and the switching circuit. In the solar power generation device according to claim 2,
The battery module is a battery module in which a plurality of series circuits including battery cells and a balancer are connected in parallel, and the panel module is a panel module in which a plurality of solar cells are connected in series and parallel. . A panel module comprising at least a plurality of solar cells connected in series;
A battery module that is connected in parallel to the panel module and is charged by the output of the panel module, and does not include a series connection;
A driving circuit comprising a reactor and a switching circuit connected in parallel to the battery module;
A multiple voltage rectifier circuit connected to a connection point of the reactor and the switching circuit;
A control circuit for controlling the switching circuit;
The output voltage of the panel module composed of the plurality of solar cells connected in series is equal to or lower than the upper limit value of the charging voltage of the battery module,
The said control circuit variably controls the duty ratio of the drive circuit which drives the said rectifier circuit according to the output voltage of the said multiple voltage rectifier circuit, The solar power generation device characterized by the above-mentioned. A panel module comprising at least a plurality of solar cells connected in series;
A battery module that is connected in parallel to the panel module and is charged by the output of the panel module, and does not include a series connection;
A drive circuit comprising a first switching circuit and a second switching circuit series body connected in parallel to the battery module;
A voltage doubler rectifier circuit connected to a connection point of the first switching circuit and the second switching circuit;
A control circuit for alternately turning on and off the first and second switching circuits;
An output voltage of a panel module composed of a plurality of solar cells connected in series is equal to or lower than an upper limit value of a charging voltage of the battery module.

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