JPH0336936A - Battery 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 [Field of Application of the Invention] The present invention relates to a charging device for a nickel-cadmium battery.

[Background of the invention]

In charging equipment for nickel-cadmium batteries.

When the voltage of the AC power source 1 changes rapidly, the output voltage of the power transformer 2, which is a charging current source, also changes, causing the charging current to change. As shown in FIG. 2, the battery voltage during charging varies depending on the charging current; the larger the charging current, the higher the battery voltage, and the smaller the charging current, the lower the battery voltage. When a 1-ΔV method is used to detect the drop in battery voltage due to full charge as a battery full charge detection method, if the power supply situation is bad and the voltage fluctuation of the AC power source is large, the battery voltage fluctuation will be 1 ΔV.
There is a problem that charging stops before the set value is exceeded and the battery is fully charged.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to prevent charging from being stopped before full charge due to sudden fluctuations in power supply.

[Summary of the invention]

In a charging device for a nickel-cadmium battery, the present invention does not perform -ΔV full charge detection control when the charging current is fluctuating due to sudden power fluctuations, but only when the charging current is within a certain range, when the charging current reaches -ΔV. This system performs a charging detection system.

[Embodiments of the invention]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figures 3A and B
, C is a flowchart 1 showing an embodiment of the present invention.
In the figure, ] is an AC power supply, 2 is a power transformer, and 3.4
．． 7 and 8 are rectifier diodes, and 5 and 6 are SCRs that control constant current charging.

9 is a charging current detection means consisting of resistors 9a, 9b, 9c, an operational amplifier 9d, and a capacitor 9e; 10 is a constant voltage power source consisting of a voltage regulator 10a, a diode 10b, and a smoothing capacitor 10c, which serves as a power source for a microcomputer 11 etc. to be described later. .

11 is salt calculation means (CPU) 11 a, ROMI l b
, ROM11c, timer lid, external interrupt manual lid
This is a single-chip microcomputer (hereinafter referred to as a microcomputer) consisting of an input port llf, an input port llf, an output port 11g, and an A/D converter llh. 12 is resistance 1.2
The battery voltage detection means consisting of a and 12b detects the battery set 14.
Divides the input voltage from 13 is a transistor 13a
, a resistor 13b13c, and a diode 13d.
It is an ignition means. 14 is a battery to be charged, battery 14a
A battery set consisting of a thermostat 14b and a thermostat 14b are connected.

16 is a transistor 16a, a resistor 16b, an i 6 c,
16d is a battery connection detection means. 17 is a power supply zero cross detection means consisting of a transistor 17a and resistors 17b and 17c.

When the power supply voltage is zero voltage, an interrupt signal is generated to the external interrupt input 11e of the microcomputer 1]2. 1.5 is the above power transformer 2, rectifier diode 3.4.7 and 8.5
CR5 and 6. Charging current detection means 9, constant voltage power supply 10,
Microcomputer 11. This charging device includes battery voltage detection means 12, SCR ignition means 13, battery connection detection means 16, and power supply zero cross detection means 1-7.

Next, the operation will be explained based on the flowcharts shown in FIGS. 3A, B, and C.

When the battery 14 is connected to the charging device 15, the microcomputer 11 determines the connection of the battery 14 based on the signal from the battery connection detection means 16, allows external interrupt from the power zero cross detection means 17, starts charging, and performs constant current charging. Control (step 20
1 to 205) and -ΔV full charge detection control (step 4
01 to 405).

Constant current charging control is performed based on the difference between the charging current data Inew obtained through the charging current detection means 9 and the A/D converter llh and the charging current setting data Icmd written in advance in the ROM 11b, and the timer set time. (
SCR ignition time) is calculated, and the charging current to the battery 14 is controlled to be constant. That is, Inew and Ie
When md is equal, leave the timer set time as it is, and set 5
Do not change the conduction angle of CR5 and CR6. Also, I new is I c
If it is smaller than md, reduce the timer set time and set 5C.
The conduction angle of R5 and R6 is increased (step 204). Conversely, when Inew is larger than Icmd, the timer cent time is increased and the conduction angle of 5CR5 and 6 is decreased (step 2).
05), I! The battery 14 charging current is controlled to be I cmd.

-ΔV charge detection control is performed by battery voltage detection means 12 and A.
When the battery voltage data Vnew obtained through the /D converter llh is larger than the battery peak voltage data Vpeak, Vnew is set as the new Vpeak and stored in RAM1.
1c (step 403). Also, as charging progresses and the battery voltage drops and Vnew becomes smaller than Vpeak, the difference between Vnew and Vpeak and the RO
-ΔV data Vdel written in M11b is compared (step 404), and when Vpeak-Vnew is larger than Vdel, it is determined that the battery is fully charged and charging is stopped. (Step 405).

When the charging current is fluctuating due to power fluctuations, the battery voltage is also fluctuating, so after constant current charging control, the Inew
Compare the difference Ierr between I cmd and charging current deviation data Idel written in the ROM 11b in advance (step 302), and if Iarr is larger than Idel,
That is, when the difference between the charging current data and the charging current setting data is large, the 1 ΔV full charge detection control is not performed. Also, I
When del is larger than Ierr, that is, when the difference between charging current data and charging current setting data is small, 1 ΔV full charge detection control is performed.

Here, the microcomputer 11 has a power supply zero cross detection means 17.
Inputs charging current data through the charging current detection means 9 and A/D converter 11h by an external interrupt from
Step 501) If battery voltage data is stored in the Ins* data area of the RAM 11e, the battery voltage detection means 1
2 and A/D converter llh, RAM
Store it in the Vnew data area of 11c Step 5
02), set the timer set time (step 503)
). In addition, the ignition of the SCR is controlled by an interrupt from the internal timer lid (Stellaf 601 to 603).

〔Effect of the invention〕

According to the present invention, even if the battery voltage fluctuates due to fluctuations in the yellow current due to fluctuations in the AC power supply voltage, charging can be prevented from stopping before the full charge period.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between charging current and battery voltage, and FIGS. 3A to 3C are flowcharts showing an embodiment of the present invention. 9 is a charging current detection means, 11 is a microcomputer, and 12 is a battery voltage detection means.

Claims (1)

[Claims] A full charge detection method for a battery comprising a detection means for detecting charging current, a detection means for detecting battery voltage, and a storage means for storing charging current and battery voltage, which detects a drop in battery voltage due to full charge. , a charging device using a -ΔV method, characterized in that -ΔV full charge detection control is performed only when a charging current is within a certain range.