JP3322925B2 - Battery charging control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main business for a photovoltaic power generation system used in a case where electric equipment is used in a desert area, a mountainous area, a campsite, a shore, an offshore, etc. where it is difficult to use commercial power. Main storage battery (first storage battery) used for storage and additional storage battery (second storage battery) used for auxiliary purposes
Further, the present invention relates to a storage battery charge control system for controlling both a storage battery used for starting an engine in a car, a boat, and the like, and an additional storage battery used for general purposes.

[0002]

2. Description of the Related Art Storage batteries are used for various purposes. In particular, in places where it is difficult to use commercial power, a photovoltaic power generation system is suitably used, and when many unusual weather days continue. It is common practice to provide a margin for the capacity of the storage battery used.

In such a photovoltaic power generation system, electricity is often used for purposes other than the main business. For example, a TV or the like may be added to a lighting system so that it can be used for entertainment. In this case, when the storage battery voltage falls below a certain reference value, control is performed such that the TV load is disconnected and power is supplied only for illumination, thereby effectively utilizing the generated power. In addition, in camping cars active in recent outdoor leisure,
It is common practice to provide an additional storage battery for a power source used in a camper, in addition to the storage battery for the engine start. In such an example, if the additional storage battery can be charged by the generator mounted on the car, it is very convenient to effectively use the generated power.

[0004]

By the way, in order to prevent the above-mentioned main operation of the photovoltaic power generation system from being hindered even if the storage battery is added, the electric power must be supplied only when there is a margin in the photovoltaic power generation amount. It is an absolute condition to use it, and if the TV set for entertainment is used too much, the lighting operation time is shortened. Also, in the case of a camper, it is obvious that a serious problem will occur if the storage battery for starting the engine is discharged.

Therefore, it is necessary to electrically separate the added storage battery from the storage battery for starting the engine. That is, it is necessary to perform control such that charging from the generator of the engine is performed while charging is not performed from the storage battery for starting the engine. Conventionally, there has been a system in which a backflow is prevented by a diode for this purpose. This is known in which an isolator is used. In this method, the output of a generator is divided by two diodes to separate an output for additional installation and an engine start.

However, in the method using the isolator, the voltage of the power generation means is reduced by about 1 V due to the diode. There is a problem that it is not possible to start power generation without flowing. In addition, a storage battery that is separately and independently added is not charged immediately after use, and thus is often left over-discharged, which significantly affects the life of the storage battery.

[0007]

Therefore, the present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide a system that can fully utilize an added load or fully utilize an added storage battery, and to provide a storage battery charge control system that minimizes overdischarge leaving by charging a solar cell.

[0008]

To achieve the above object, a storage battery charging control system according to the present invention comprises a storage battery connected between a first storage battery charged by a power generation means and a second storage battery. A charge control system, comprising: current detection means for detecting the magnitude and direction of a current flowing between the storage batteries; voltage detection means for detecting a terminal voltage of the storage batteries; and switch means for opening and closing the storage batteries. When the voltage detecting means detects that the terminal voltage of the first storage battery exceeds the first set voltage and is higher than the terminal voltage of the second storage battery, the switch means closes. The second storage battery is controlled to be maintained and charged by the power generation means, and at least the voltage detection means detects that the terminal voltage of the second storage battery has exceeded a second set voltage. Or when the current detecting means detects that a current has flowed from the second storage battery side to the first storage battery side, the switch means is maintained in an open state, and the current detecting means detects When it is detected that the magnitude of the current flowing between the storage batteries exceeds a set value, the switching means is repeatedly opened and closed to control the current to be constant.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below in detail.

First, an overall configuration of the present system will be described with reference to FIG. Solar power system S for main business
Is provided with a first solar cell P1 as a power generation means and a storage battery B1 as a first storage battery charged by the first solar cell P1. The storage battery charge control system M according to the present invention is connected to the photovoltaic power generation system S. The current from the second photovoltaic cell P2 is passed through the backflow prevention diodes D1 and FET1. This current is further divided by the shunt diodes D2 and D3, and the added second
The storage battery B2 is a storage battery, a load for entertainment (for example, a television set) L1, and the storage battery B1.

The solar cell P1 provided in the photovoltaic power generation system S is connected to a storage battery B1, and this storage battery B1 is used for a main work load L1 (light in this embodiment such as a refrigerator, a medical refrigerator, and a communication device). Lamps such as lamps). Note that the first control circuit C1 mainly performs overcharge and overdischarge of the storage battery B1 and the like. The charging current from the photovoltaic power generation system S can charge the additional storage battery B2 through FET2 and FET3 which are switch means for opening and closing the first and second storage batteries provided in the storage battery charging control system M. it can. The storage battery B2 is configured so that a load L2 can be added.

The second control circuit C2 provided in the storage battery charging control system M includes voltage detecting means for detecting the terminal voltage of the storage battery B2 and the terminal voltage of the storage battery B1, and the second control circuit C2 detects the terminal voltage of the storage battery B1. If it is lower than the set value, the control is performed so that the switch means FET2 and FET3 are turned off. In this case, the storage battery B2 is not charged from the solar power generation system S. On the other hand, the amount of electricity used in the photovoltaic power generation system S is small, the storage battery B1 approaches a fully charged state, the terminal voltage of the storage battery B1 exceeds the first set voltage, and the terminal voltage is higher than the terminal voltage of the storage battery B2. In this case, the charging current from the photovoltaic power generation system S flows to the storage battery B2 by controlling the FET2 and the FET3 to the ON state. That is, the first set voltage described here is changed to the storage battery B1 used in the photovoltaic power generation system S.
Is set to a value that indicates almost full charge,
Only when surplus power is generated in the system, the operation of charging the added storage battery B2 is performed. In addition, the storage battery B
When the voltage detecting means detects that the battery 2 is fully charged and exceeds the second set voltage, the FETs 2 and 3 are turned off.

Further, a minute resistor RS as a current detecting means is connected between the terminal of the storage battery B1 and the FET2.
This is because when the FET2 and the FET3 are turned on, the storage battery B
1 flows from the storage battery B2 to the storage battery B2. By limiting the current value, when a charging current exceeding the allowable current value of these FETs flows, protection of the FET as a switching means and protection of the added storage battery B2 are performed. Charging current can be limited. That is, by using the voltage generated at both ends of the micro-resistor RS, when this voltage value exceeds the set value, the control for turning off the FET2 and the FET3 is performed. By providing a time constant for the on / off control, a general switching operation can be easily performed, and it can be clamped to a constant charging current value.

Next, a case where the present storage battery charging control system is connected to a power generation system using an engine of an automobile or a ship will be described. As shown in FIG. 2, instead of the above-described solar power generation system S, the output of the generator G by the engine is connected to the terminal of the first storage battery B3 in parallel with the storage battery B3.

For example, when the terminal voltage of the storage battery B3 is lower than the set value while the engine is stopped and charging from the generator G is not performed, as described above, the FETs 2 and F
ET3 is turned off. Conversely, the engine is started and the generator B charges the storage battery B3.
Approaches the fully charged state, and when the terminal voltage VB3 of the storage battery B3 exceeds the set voltage, the FET2 and the FET3 are turned on, so that the charging current flows to the storage battery B2. That is, even in this case, when the set voltage is set to a value indicating the fully charged state of the storage battery B3, an operation of charging the added storage battery B2 only when surplus power is generated in the power generation system by the engine can be performed. it can. The function of the minute resistor RS provided between the terminal of the storage battery B3 and the FET 2 has already been described with reference to FIG.

Here, when the above-mentioned generator G is stopped, or when the load L2 of the photovoltaic power generation system
When the charging current to the storage battery B2 decreases due to an increase in the power supply to the storage battery B2 and the current is further reversed, even if the terminal voltage of the storage battery B3 exceeds the set value,
Conversely, a discharge current may flow from the storage battery B2 to the storage battery B2. In order to prevent this discharge, a comparator H is provided in the control circuit. When the terminal voltage of the storage battery B2 becomes higher than the terminal voltage of the storage battery B3, the terminal voltage of the storage battery B3 becomes higher than the first set value. FE even if high
It can be controlled to turn off T2 and FET3.

[0017]

As described above, when the storage battery charging control system according to the present invention is applied to a camper or the like, it is possible to use up the added second storage battery, and to maximize the capacity of this storage battery. There is an effect that can be done.

Further, in the present system, the second storage battery added by the power generation means can be charged.
Even when the storage battery is completely used up to the overdischarged state, for example, the battery can be charged to some extent during the day of the next day.
Damage of the storage battery can be reduced as much as possible.

Further, an additional storage battery, which could not be connected conventionally, can be connected to the IC-based power generation means (engine generator), which is very convenient in use.

When the present system is added to the solar power generation system, the surplus power of the solar power generation system can be stored in the additional storage battery. No troubles such as operation stop occur. As a result, it is possible to expect a remarkable effect that the energy use efficiency becomes extremely high and surplus power can be supplied safely and effectively in addition to the intended use.

Further, when it is detected by the current detecting means that the magnitude of the current flowing between the two storage batteries exceeds the set value, the switching means is repeatedly opened and closed to control the current to be constant, It is possible to protect the switch means and limit the current to the storage battery.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a storage battery charging control system according to the present invention.

FIG. 2 is an overall configuration diagram showing another embodiment of the storage battery charging control system according to the present invention.

[Explanation of symbols]

P1, P2: solar cell (power generation means), G: generator (power generation means), FET1, FET2: switch means, B1, B
3: First storage battery, B2: Second storage battery, RS: Micro resistor (current detection means), C1, C2: Control circuit, M: Storage battery control system

Claims (1)

(57) [Claims] 1. A storage battery charging control system connected between a first storage battery charged by a power generating means and a second storage battery, wherein a magnitude and a direction of a current flowing between the two storage batteries are detected. Current detecting means, a voltage detecting means for detecting a terminal voltage of the two storage batteries, and a switch means for opening and closing between the two storage batteries, wherein the terminal voltage of the first storage battery is set to a first voltage by the voltage detecting means. When it is detected that the voltage exceeds the set voltage and is higher than the terminal voltage of the second storage battery, control is performed such that the switch means is kept closed to charge the second storage battery by the power generation means,
At least when the voltage detection means detects that the terminal voltage of the second storage battery has exceeded a second set voltage, or when the current detection means causes a current to flow from the second storage battery to the first storage battery. The switch means is maintained in an open state when the flow is detected, and when the magnitude of the current flowing between the two storage batteries exceeds a set value by the current detection means, the switch means is controlled. And a battery charging control system for controlling the current to be constant by repeatedly opening and closing the battery.