JPS6289435A - Charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (b) Conventional technology Solar cells made of silicon have been developed and are being applied to consumer devices, but their output is greatly affected by sunlight conditions, so backup It is common to use a secondary battery in combination for this purpose. For example, as a power source for a solar battery equipped with a rechargeable battery charging device,
There is a publication No.-198846. This consists of solar cells that generate electricity from sunlight, multiple storage batteries that are connected in series to each other and store the power generated by the solar cells, and multiple storage batteries that are constructed by dividing each previous station storage battery into a predetermined number of batteries. A first switch group consisting of a plurality of switches that respectively connect blocks to the solar cells, and a plurality of other storage battery blocks configured by dividing each of the storage batteries into a number different from the predetermined number, connect the blocks to the solar cells. This device is equipped with a second switch group consisting of a plurality of switches each connected to a second switch group, and a control section that controls on/off of each switch in both switch groups. Sometimes, by simply switching on the control unit from the first switch group to the second switch group or from the second switch group to the first switch group and turning on, the fluctuation in the output voltage of the solar cell is reduced and the voltage is almost the optimum output voltage. It is possible to efficiently charge the lead-acid battery due to its inexpensive structure, and it is also possible to increase the low output voltage of the solar cell and input it to the inverter without using an NC-DC converter. , solar cells and inverters can be operated efficiently. However, if the weather is bad depending on the season and the output is not sufficient to charge the lead-acid battery, there is a problem that the load cannot be operated and the system does not function properly.

In view of these points, a battery charging circuit using a solar battery and a commercial AC power supply has been proposed, the outline of which is shown in the block diagram in Figure 4 (for details, see NEDo Photovoltaic Symposium 83 Proceedings P, 69r). (See ``Current Status and Future Challenges of Photovoltaic Power Research and Development'').

In devices like this, which charge a storage battery with the generated output of a solar cell and supply the stored power to a load, in order to prevent the storage battery from overdischarging due to insufficient generated power, the load must be disconnected or the commercial power supply A method is adopted in which the storage battery is charged using a separate power source such as a generator or a generator.

In FIG. 4, the large-scale diode (101) charges the storage battery (103) through the backflow prevention diode (102).

On the other hand, the secondary output of the transformer (104) is the rectifier and smoothing circuit (lo
Similarly, the storage battery (103) Ic is connected via the storage battery (103) Ic.

When the storage battery (103) falls below the lower limit value set by each energy storage company, commercial electricity (10g) is connected to the negative side of the transformer (1os) by closing the switch (107), and charging starts. Ru. Then, when the electricity storage capacity I of the storage battery increases due to the electric current supplied by the commercial power and exceeds the set upper limit, the commercial power supply (106) switches the switch (107).
) is opened, the battery is disconnected and charging stops. During this time, the charging current to the storage battery (1os) is the sum of the currents of the commercial power source (XOS) and the solar cells (lot). At the same time, a discharge current is also generated from the load (log) K.

In power supply devices that use both solar power generation and commercial power, the purpose is often to save power, and the commercial power is used as a backup when the generated power is insufficient. In addition, in such applications, storage batteries are usually of a floating charging type, so they must be charged evenly at regular intervals to extend their lifespan, and are therefore used as a charging power source. However, the charging current fluctuates rapidly due to fluctuations in the power generation of the solar cells and fluctuations in the load, and when charging using a commercial power source, it is difficult to determine the amount of electricity being charged, resulting in the problem that equal charging cannot be carried out accurately. Particularly in the case of nickel-cadmium batteries, in which the state of charge is difficult to reflect on changes in terminal voltage, the method becomes complicated, such as by adopting a method of integrating the charging current. Generally, a full charge detection method using a temperature switch is used, but if the charging current does not reach a specified value or higher, the detection will be inaccurate due to the influence of the outside temperature.

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are that in a charging system ft1l that uses a commercial AC power source as a backup for a solar cell, the charging current to the secondary battery is constant when charging by the commercial AC power source. It is important to keep it.

2) Means for solving the problem Connect a solar cell and a commercial AC power source in parallel to a rechargeable secondary battery, and use both together The power generation output of the battery decreases and the secondary battery starts discharging. is started just before
Further, the charging is terminated immediately before the secondary battery reaches full charge. Furthermore, commercial AC power is rectified and then smoothed and converted into DC, and a function is provided to control the output current value by commands.

(E) Operation When the output of the solar cell is insufficient and photoelectric current is supplied to the secondary battery from the commercial AC power source, the control function detects the charging current value supplied to the secondary battery, and this charging current is The amount of charging current supplied by the commercial AC power source is adjusted so that it is maintained at the set constant value.

(F) Embodiment The charging device of the present invention will be described in detail below with reference to an embodiment of the drawings.

Solar pond made of amorphous silicon (2)
(4) is a nickel-cadmium battery connected between both output terminals of the solar cell (1) via a backflow prevention diode (3); This is a load connected in parallel to the

(5) is a commercial AC power supply, (6) is a transformer whose secondary coil is connected via a switch (7), ]8) is connected to the secondary coil of the transformer (6). The rectifying and smoothing circuit section (9) is connected to the rectifying and smoothing circuit section (8).
This is a C-DC converter, which is configured with a chopper circuit, and has the function of adjusting the output current value according to a command.

(1) A comparator that gives commands to the ED c - DC converter (9), one input is the detected value of the lightning and current detector (11) inserted in series with the battery (2), The other input is a set value (1). The DC-DC converter (9) adjusts the output according to the command of the comparator +1 (m), and the comparator output is the set value. It operates in the direction in which the output signals of Shino and the current detector (11) match.

The purpose of the DC-DC converter (9) can be achieved by the well-known tt technique, so a detailed explanation will be omitted, but the average value of the output current can be adjusted arbitrarily by controlling the width of the chopper. , generally uses a switching power supply system that is used in DC stabilized power supplies. The output current C of the DC-DC converter (9) is supplied to the battery (2) via a diode.

In the charging device having the above configuration, the output signal of the current detector (11) has a positive polarity if the direction of the current that charges the battery (2) is positive, and conversely, the output signal of the current detector (11) has a positive polarity when the current that charges the battery (2) is positive. The current is of negative polarity. Here, the set value 0 to 0 is positive polarity, and the DC-DC converter (9) is connected to the battery (2
) From the charging current (supply C from the solar cell), the output current from the DC-DC converter △
In order for the pump to operate normally, the set value (
The condition is that the set value (actual current corresponding to one odor) is higher than the maximum value of the charging current that can be generated by the solar cell (1) alone.

In other words, the condition is (-U)=IC 10 Pv-Work, that is, IC Mit B-(Work PV-Work L). Here, construct DC-DC converter t9
1Jl" Due to its nature (function), it does not take a negative value, so in order to keep the bias constant as described above, it must be set at pv-IL.

FIG. 2 shows the changes over time of each current in FIG. 1. When the charging current exceeds the set value, this is detected by the comparator (10) and the DC-DC converter (9) is controlled to reduce the IC. Then, IC decreases in accordance with the increment of power pv to keep the charging current jB constant. Time b, time t! When the load (4) changes, Ii increases. When the main U charging current IB falls below the set value, this is detected by the comparator C, and the DC-DC converter +91 is controlled to increase the IC. Charge the universe, keep the flow in one universe.

At time t5, the power PV takes the maximum value, but the IC becomes the minimum value. And the output current of the solar pond f1) P■
The output current IC of the DC-DC converter (9) increases 17 in accordance with the decrease in the charge current, and the charging current is maintained at one level.

FIG. 3 shows another example of the charging device of the present invention, in which a commercial AC power supply (
6) is equipped with a current control function to realize output control.

The differences from Figure 1 are the commercial AC power supply (5) and the transformer (
A bidirectional thyristor 04) is inserted between the secondary coil of 6) instead of the switch (7), and the gate of the thyristor H has a firing phase that controls the firing phase of the thyristor (1). The control circuit is connected 1.y, and the control circuit is connected to the comparator (l) (7). Adjust the input voltage of the transformer (6) by changing the firing phase of the thyristor (l) and as a result change the current of the 6J IC,
Keep charging current IB constant.

(G) Effects of the Invention As described above, the present invention connects a solar cell and a commercial AC power source in parallel to a rechargeable secondary battery, and uses both together to supply a charging current to the secondary battery. It is a device that adjusts the amount of charging current supplied from the solar cell and the amount of charging current supplied from the commercial AC power source while the charging current is supplied from the commercial AC power source, so that the equal charging current is constant. Since the charge amount can be regulated according to time, and the charging current can be prevented from becoming excessive, the life of the battery can be extended.

[Brief explanation of drawings]

Fig. 1 is an implementation circuit diagram of the charging device of the present invention, and Fig. 2 is a circuit diagram of the charging device of the present invention.
The time-dependent change characteristics of each current shown in the figure, Figure @3 is another implementation circuit diagram, and Figure 4 is a conventional circuit diagram corresponding to Figure @1. 12)...Secondary battery, (1)...Solar cell, (6)
...Commercial AC power supply, (4)...Load.

Claims (2)

[Claims] (1) A solar cell and a commercial AC power source are connected in parallel to a rechargeable secondary battery, and both are used together to supply charging current to the secondary battery, and the charging current is a commercial AC power source. The amount of charging current supplied from the commercial AC power source is adjusted so that the sum of the amount of charging current supplied from the solar cell and the amount of charging current supplied from the commercial AC power source remains constant while being supplied from the power source. Charging device. (2) A load is connected to the secondary battery, and the solar cell and the commercial AC power supply are used to charge the secondary battery while adjusting the amount of charging current supplied from the commercial AC power source so that the total amount of charging current supplied is constant. The above-mentioned device for charging a secondary battery is characterized in that, when discharging from the secondary battery to a load occurs simultaneously during charging of the secondary battery, the net charging current to the secondary battery is adjusted. A charging device according to claim 1.