JP2010045930A - Charging circuit and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a storage battery from deteriorating due to a very small charging current. <P>SOLUTION: A coil 3 connected to a solar cell 1 generates a magnetic field corresponding to the magnitude of a current supplied from the solar cell 1. If a magnetic flux density B of a magnetic field H generated by the coil 3 exceeds B<SB>1</SB>, a hall IC 5 controls so that a charging current can flow from the coil 3 to a storage battery 2. On the contrary, if the magnetic flux density B becomes not more than B<SB>2</SB>smaller than B<SB>1</SB>, the hall IC 5 controls so that a charging current does not flow from the coil 3 to the storage battery 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charging circuit and a charging method for charging an electric power generated by a solar battery to a storage battery, and more particularly to a charging circuit and a charging method capable of preventing deterioration of the storage battery due to a minute charging current.

  Conventionally, when weather observation or monitoring is performed in a place where it is difficult to secure a power supply infrastructure, a solar cell system combining a solar cell and a storage battery can be used as a power source for data collection and information transmission. In the solar cell system, for example, power generated by the solar cell is supplied to the load during the daytime, the storage battery is charged with surplus power, and necessary power is supplied by discharging from the storage battery at night.

  As an example of such a solar cell system, for example, Patent Documents 1 and 2 describe an independent solar power generation system in which a storage battery and a solar cell are combined. Specifically, Patent Document 1 discloses a Ni-MH (nickel-hydrogen) storage battery that is charged by a first converter connected to the output of the solar battery and a charger connected to the output of the first converter. And a second converter connected to the output of the first converter and the output of the electric double layer capacitor and connected to the Ni-MH battery via a backflow prevention diode, and connected to the output of the second converter. A stand-alone photovoltaic system with a load is described.

  Patent Document 2 discloses a solar cell that generates electric power by sunlight, a converter connected to the output of the solar cell, an electric double layer capacitor connected to the output of the converter, an output of the converter, and an electric double layer. Independent solar light comprising a plurality of chargers connected to capacitors, a plurality of Ni-MH batteries connected corresponding to the chargers, and a load connected to the outputs of the plurality of Ni-MH batteries A power generation system is described.

  Thus, when charging a storage battery with a solar battery, it is common to charge via a converter. The converter outputs a constant voltage to the storage battery with the solar battery as an input, and matches the output voltage with the charging voltage of the storage battery. Here, the generated electric power of the solar cell greatly fluctuates due to sunlight, but the fluctuation appears as an increase or decrease in the output current (charging current) of the converter. That is, even if the power generation amount decreases, the output voltage (charging voltage) of the converter does not change, and the output current (charging current) decreases.

JP 2000-250646 A JP 2001-069688 A

  However, normally, the optimum value is set for the charging current of the storage battery, and when the charging current becomes very small, the charging efficiency is remarkably lowered and the storage battery is not charged. In that case, most of the electric power input to the storage battery is converted into heat, but there is a problem that the deterioration of the storage battery proceeds due to this exothermic reaction.

  The present invention has been made to solve the above-described problems caused by the prior art, and an object thereof is to provide a charging circuit and a charging method capable of preventing deterioration of a storage battery due to a minute charging current.

  In order to solve the above-described problems and achieve the object, the present invention is a charging circuit that charges a storage battery with power generated by a solar battery, and is connected to the solar battery and supplied from the solar battery. An inductance for generating a magnetic field according to the magnitude of the magnetic field, and when the magnetic flux density of the magnetic field generated by the inductance exceeds a first threshold value, control is performed so that a charging current flows from the inductance to the storage battery, and the magnetic flux Switch means for controlling the charging current not to flow from the inductance to the storage battery when the density is equal to or lower than a second threshold value smaller than the first threshold value.

  The present invention also relates to a charging method for charging a storage battery with electric power generated by a solar battery, wherein an inductance connected to the solar battery generates a magnetic field corresponding to the magnitude of a current supplied from the solar battery. And when the magnetic flux density of the magnetic field generated by the inductance exceeds a first threshold value, the switching means controls the charging current to flow from the inductance to the storage battery, and the magnetic flux density is And a step of controlling so that a charging current does not flow from the inductance to the storage battery when it is equal to or smaller than a second threshold value smaller than the threshold value.

  According to the present invention, there is an effect that it is possible to prevent deterioration of the storage battery due to a minute charging current.

  Exemplary embodiments of a charging circuit and a charging method according to the present invention will be explained below in detail with reference to the accompanying drawings. In addition, a present Example demonstrates the case where this invention is applied to the solar cell system which combined the solar cell and the storage battery, and demonstrates centering on the case where the electric power generated by the solar cell is charged to a storage battery.

  First, the configuration of the solar cell system according to the first embodiment will be described. FIG. 1 is a block diagram illustrating the configuration of the solar cell system according to the first embodiment. As shown in the figure, this solar cell system includes a solar cell 1, a storage battery 2, a coil (inductance) 3, a diode 4, and a Hall IC 5. Here, the coil 3, the diode 4, and the Hall IC 5 constitute a charging circuit that charges the storage battery 2 with the electric power generated by the solar battery 1.

  The solar cell 1 generates electric power by converting solar energy into electric energy.

  The storage battery 2 stores the electric power generated by the solar battery 1. For example, a Ni-MH storage battery is used as the storage battery 2.

  The coil 3 has one terminal connected to the solar cell 1 and the other terminal connected to the diode 4. The coil 3 generates a magnetic field H corresponding to the magnitude of the current supplied from the solar cell 1.

  The diode 4 has an anode terminal connected to the coil 3 and a cathode terminal connected to the storage battery 2. This diode 4 prevents the backflow of current from the storage battery 2 to the solar battery 1.

  The Hall IC 5 is switch means in which the positive terminal of the contact is connected between the coil 3 and the diode 4, and the negative terminal of the contact is connected between the storage battery 2 and the solar battery 1. The Hall IC 5 is a switch that switches on / off of the connection between both terminals based on the Hall element that detects the magnetic field H generated by the coil 3 and the magnetic flux density B of the magnetic field H detected by the Hall element. And a switch.

  In the first embodiment, the Hall IC 5 detects the magnetic field H generated by the coil 3 and controls the charging current flowing to the storage battery 2 based on the magnitude of the magnetic flux density B of the detected magnetic field H. This makes it possible to prevent deterioration of the storage battery due to a minute charging current.

Specifically, the Hall IC 5 turns off the changeover switch when the magnetic flux density B of the magnetic field H detected by the Hall element exceeds the first threshold value B ₁ . Thereby, the current flowing through the Hall IC 5 is interrupted, and as a result, the charging current flows from the coil 3 to the storage battery 2 through the diode 4.

On the other hand, the Hall IC 5 turns on the changeover switch when the magnetic flux density B detected by the Hall element becomes equal to or less than B ₂ which is a second threshold value smaller than B ₁ . Here, the current supplied from the solar cell 1 does not flow to the storage battery 2 but flows to the Hall IC 5 via the coil 3. At this time, since the diode 4 is connected to the storage battery 2, the storage battery 2 is not short-circuited by the Hall IC.

Here, the relationship between the current flowing through the coil 3 and the charging current supplied to the storage battery 2 will be described. FIG. 2 is a diagram for explaining the relationship between the current flowing through the coil 3 and the charging current supplied to the storage battery 2. In this drawing, (a) shows a temporal change of the current I _L flowing in the coil 3, the vertical axis represents the magnitude of the current I _L, the horizontal axis represents the time t. On the other hand, (b) shows the change over time of the charging current I _C supplied to the storage battery 2, the vertical axis shows the magnitude of the charging current I _C , and the horizontal axis shows the time t.

Moreover, in (a) and (b) of the figure, I ₁ shown is the magnitude of the current flowing through the coil 3 when the magnetic flux density B becomes B _1, and I ₂ is the magnetic flux density B is the magnitude of the current flowing in the coil 3 when the B _2. These I ₁ and I ₂ have a relationship of I ₁ > I ₂ , and I ₂ is set to be equal to or higher than the minimum current that can charge the storage battery 2.

First, as shown in the figure, it is assumed that I _L and I _C are 0 at the time of t = 0, and the changeover switch of the Hall IC 5 is turned on.

As time t elapses, _IL gradually increases as shown in FIG. Then, when I _L exceeds I ₁ , that is, when the magnetic flux density B of the magnetic field H generated by the coil 3 exceeds B ₁ , the changeover switch of the Hall IC 5 is turned off. Thus, as shown in the same figure (b), to flow the charging current I _C to the battery 2.

Thereafter, when the time t further elapses, I _L gradually decreases as shown in FIG. Then, when I _L becomes I ₂ or less, that is, when the magnetic flux density B of the magnetic field H generated by the coil 3 becomes B ₂ or less, the Hall IC 5 turns on the changeover switch. Thus, as shown in the same figure (b), the charging current I _C flowing through the battery 2 becomes zero.

As described above, the Hall IC 5 repeats the control of the charging current I _C based on the change of the current I _L flowing through the coil 3, that is, the change of the magnetic flux density B of the magnetic field H generated by the coil 3. A pulsed charging current I _C is sequentially supplied.

For example, many solar radiation, when the power generation by the solar cell 1 is sufficiently performed, I _L is I ₂ greater than, in other words, when the changeover switch of the hole IC5 is off continues. Therefore, in this case, the storage battery 2 continues to be charged with a charging current I _C that is greater than or equal to the minimum charging current.

When the solar radiation is lowered during charging, the switching switch hole IC5 is turned on when the current I _L flowing in the coil 3 becomes I ₂ or less. Here, if the addition amount of solar radiation decreases, a current I _L flowing through the coil 3 is not reached I _1, continues the state changeover switch hole IC5 is on. Therefore, in this case, charging of the storage battery 2 is completely stopped.

  Next, the procedure of the charging method in the solar cell system according to the first embodiment will be described. FIG. 3 is a flowchart illustrating the procedure of the charging method in the solar cell system according to the first embodiment.

  As shown in the figure, in this solar cell system, first, the Hall IC 5 turns on the changeover switch (step S1). Thereby, the current supplied from the solar cell 1 does not flow to the storage battery 2 but flows to the Hall IC 5 via the coil 3.

  Thereafter, the coil 3 generates a magnetic field H corresponding to the magnitude of the current supplied from the solar cell 1 (step S2).

Subsequently, holes IC5 detects the magnetic field H generated by the coil 3, (step S3, Yes) if the detected magnetic flux density B exceeds B _1, to turn off the switch (step S4). As a result, a charging current flows from the coil 3 to the storage battery 2.

Thereafter, when the magnetic flux density B becomes B ₂ or less (step S5, Yes), the Hall IC 5 turns on the changeover switch again (step S1). This prevents charging current from flowing from the coil 3 to the storage battery 2.

  By repeating the above procedure, the solar cell system intermittently repeats charging of the storage battery 2.

As described above, in Example 1, the coil 3 connected to the solar cell 1 generates a magnetic field according to the magnitude of the current supplied from the solar cell 1. The Hall IC 5 controls the charging current to flow from the coil 3 to the storage battery 2 when the magnetic flux density B of the magnetic field H generated by the coil 3 exceeds B ₁ . On the other hand, when the magnetic flux density B is less than B ₂ which is smaller than B ₁ , the Hall IC 5 controls the charging current not to flow from the coil 3 to the storage battery 2.

Thereby, when the magnetic flux density becomes B ₂ , the charging current lower than the current I ₂ flowing through the coil 3 does not flow into the storage battery 2, so that the deterioration of the storage battery 2 due to a minute charging current can be prevented. It becomes possible. Moreover, since the fall of charging efficiency by supplying a very small charging current to the storage battery 2 can be prevented, it becomes possible to charge the storage battery 2 efficiently.

In Example 1, the magnitude of the current I _L flowing through the coil 3 when the magnetic flux density B matches the second threshold B ₂ is equal to or greater than the minimum current that can charge the storage battery 2. Since the value is set as described above, it is possible to prevent the charging battery 2 from being supplied with a charging current that is so fine that charging is impossible, and to charge the storage battery 2 more efficiently.

  In the first embodiment, the case where the Hall IC 5 is used as the switch means for controlling the charging current supplied to the storage battery 2 has been described. However, the present invention is not limited to this. For example, the coil and the switch It is also possible to use a relay having contacts that operate as means.

  Therefore, in the following, a case where a relay is used will be described as a second embodiment. FIG. 4 is a block diagram illustrating the configuration of the solar cell system according to the second embodiment. As shown in the figure, the solar cell system according to the second embodiment includes a relay 10 instead of the coil 3 and the Hall IC 5 in the first embodiment. Here, the relay 10 and the diode 4 constitute a charging circuit that charges the storage battery 2 with the electric power generated by the solar battery 1.

  The relay 10 has a coil 11 and a contact 12 that operates as a switch means. Here, the coil 11 has one terminal connected to the solar cell 1 and the other terminal connected to the diode 4. Similar to the coil 3 in the first embodiment, the coil 11 generates a magnetic field H corresponding to the magnitude of the current supplied from the solar cell 1.

  The contact 12 has one terminal connected between the coil 11 and the diode 4, and the other terminal connected between the storage battery 2 and the solar battery 1. The contact 12 switches on / off the connection between both terminals based on the magnitude of the magnetic flux density B of the magnetic field H generated by the coil 11.

  And in this Example 2, this relay 10 controls the charging current which flows into the storage battery 2 based on the magnitude | size of the magnetic flux density B of the magnetic field H which the coil 11 generate | occur | produced, Deterioration of the storage battery by a minute charging current It is possible to prevent.

Specifically, the relay 10 turns off the contact 12 when the magnetic flux density B of the magnetic field H generated by the coil 11 exceeds the first threshold value B ₁ . Thereby, the current flowing through the contact 12 is interrupted, and the charging current flows from the coil 11 to the storage battery 2 via the diode 4.

On the other hand, the relay 10 turns on the contact 12 when the magnetic flux density B generated by the coil 11 becomes equal to or less than B ₂ which is a second threshold value smaller than B ₁ . Here, the current supplied from the solar cell 1 does not flow to the storage battery 2 but flows to the contact 12 via the coil 3. At this time, since the diode 4 is connected to the storage battery 2, the storage battery 2 is not short-circuited by the contact 12.

As described above, when the magnetic flux density B becomes B ₁ , the relay 10 turns off the changeover switch, and when the magnetic flux density B becomes equal to or less than B _2, which is the second threshold value smaller than B ₁ , the switching is performed. The switch can be turned on because the coil 3 has hysteresis. Hysteresis as used herein refers to a curve when the magnetic flux density indicating magnetization increases and decreases in the relationship between the external magnetic field and the magnetization of the magnetic material when the magnetic material placed in the magnetic field is magnetized. This is because the curve does not match.

In other words, hysteresis is when the magnitude of the external magnetic field does not match between the timing when the magnetization switches from negative to positive and the timing when the magnetization switches from positive to negative, and the magnetic field when the magnetization switches from negative to positive. Is larger than the magnitude of the magnetic field when switching from positive to negative. Therefore, in the relay 10, when the magnetic flux density B of the magnetic field H generated by the coil 11 exceeds B ₁ , the contact 12 is turned off, and when the magnetic flux density B becomes less than B _{2 which is} smaller than B ₁ , Contact 12 is turned on.

The relay 10 has been specifically described above. However, as the relay 10, a relay that is widely used can be used as appropriate. That is, when the magnitude of the current when the magnetic flux density is B ₁ in the coil is I ₁ and the magnitude of the current when the magnetic flux density is B ₂ is I ₂ , the input current of the coil is I ₁ . contacts when the became switches from oN to oFF, the contact at the time when the input current becomes I ₂ may be selected relay specifications switched from off to on. At this time, the value of I ₂ is desirably equal to or greater than the minimum charging current that can charge the storage battery 2.

As described above, in the second embodiment, the relay 10 having the coil 11 and the contact 12 is used, and the coil 11 connected to the solar cell 1 depends on the magnitude of the current supplied from the solar cell 1. Generate a magnetic field. The contact 12 controls the charging current to flow from the coil 11 to the storage battery 2 when the magnetic flux density B of the magnetic field H generated by the coil 11 exceeds B ₁ . On the other hand, when the magnetic flux density B is less than B ₂ which is smaller than B ₁ , the contact 12 controls the charging current not to flow from the coil 11 to the storage battery 2.

As a result, as in the first embodiment, when the magnetic flux density becomes B ₂ , the charging current lower than the current I ₂ flowing through the coil 11 does not flow into the storage battery 2, so that the storage battery with a minute charging current is used. 2 can be prevented. Moreover, since the fall of charging efficiency by supplying a very small charging current to the storage battery 2 can be prevented, it becomes possible to charge the storage battery 2 efficiently.

  Further, in the second embodiment, since a relay that is generally spread is used, it is not necessary to prepare a special control device for controlling the charging current supplied to the storage battery 2. Therefore, the circuit can be configured easily, and it is possible to realize a reduction in cost and a reduction in failure rate.

  As described above, the charging circuit and the charging method according to the present invention are useful when charging the storage battery with the electric power generated by the solar battery, and in particular, it is required to prevent deterioration of the storage battery due to a minute charging current. Suitable for cases.

1 is a block diagram illustrating a configuration of a solar cell system according to Example 1. FIG. FIG. 3 is a diagram for explaining a relationship between a current flowing through a coil 3 and a charging current supplied to the storage battery 2. 3 is a flowchart illustrating a procedure of a charging method in the solar cell system according to the first embodiment. It is a block diagram which shows the structure of the solar cell system which concerns on the present Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Storage battery 3 Coil 4 Diode 5 Hall IC
10 Relay 11 Coil 12 Contact

Claims (5)

A charging circuit for charging a storage battery with electric power generated by a solar battery,
An inductance connected to the solar cell and generating a magnetic field according to the magnitude of the current supplied from the solar cell;
When the magnetic flux density of the magnetic field generated by the inductance exceeds a first threshold value, control is performed so that a charging current flows from the inductance to the storage battery, and the magnetic flux density is smaller than the first threshold value. Switch means for controlling charging current not to flow from the inductance to the storage battery when
A charging circuit comprising:   The value of the current flowing through the inductance when the magnetic flux density matches the second threshold value is set to be equal to or greater than the lowest current that can charge the storage battery. The charging circuit according to claim 1.   3. The Hall IC according to claim 1, wherein the switch means is a Hall IC that detects a magnetic field generated by the inductance and controls the flow of the charging current based on the magnitude of the magnetic flux density of the detected magnetic field. The charging circuit as described.   The charging circuit according to claim 1, further comprising a relay having the inductance and a contact that operates as the switch unit. A charging method for charging a storage battery with electric power generated by a solar battery,
An inductance connected to the solar cell generates a magnetic field according to the magnitude of the current supplied from the solar cell;
When the magnetic flux density of the magnetic field generated by the inductance exceeds a first threshold value, the switch means controls the charging current to flow from the inductance to the storage battery, and the magnetic flux density is smaller than the first threshold value. A step of controlling the charging current not to flow from the inductance to the storage battery when the second threshold value is reached or less;
The charging method characterized by including.

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