JPS6016173B2 - Storage battery charging device - Google Patents

Description

Detailed Description of the Invention The present invention operates an inverter with a rectified voltage of an AC power supply, charges a storage battery with a half-wave current obtained by rectifying its output, detects a predetermined state of charge of the storage battery, and oscillates the inverter. The present invention relates to a storage battery charging device that reduces output.

In this type of conventional device, the predetermined state of charge of the storage battery is detected based on the storage battery voltage.

However, when a storage battery such as a nickel-cadmium battery is continuously charged, the storage battery charging voltage characteristic A has a peak point a as shown in FIG.
occurs at a point before the saturation point t of the storage battery charging capacity characteristic B. Further, since the slope near the peak point of characteristic A is difficult to detect, the predetermined storage battery voltage V is detected in the range where the slope is large. This detection time is before the peak time t2, and the charging capacity at that time is lower than the saturation value, so in order to increase the charging capacity even a little, without immediately switching to trickle charging from the detection time,
The battery is being moved to joggle charging. Therefore, the average charging current has characteristic C, which has the disadvantage that the charging capacity cannot be sufficiently increased and the charging time becomes longer. Furthermore, there is a drawback that the conventional charging device cannot be incorporated into an electronic device due to noise generated during jogging charging. The present invention was invented in view of this point, and does not detect the storage battery voltage.
A differentiating circuit is placed in parallel with the storage battery, and by focusing on the fact that its differential output exhibits special characteristics related to the storage battery charging voltage characteristics, the system detects a predetermined state of charge of the storage battery and immediately shifts to trickle charging without jogging charging. This is something that we are trying to encourage. First, the principle of a charging device using a differential circuit will be explained based on FIGS. 2 and 1.

'1) may be a power supply device that rectifies an AC power source to produce a constant current output or a constant voltage output, or may be constructed using other batteries. A differentiating circuit 4 and a voltage dividing circuit 5 are connected in parallel with a storage battery 3 that is charged via a switch circuit 2 by the output of the power supply device 1, and an intermediate point between the differential output of the output terminal 6 of the differentiating circuit 4 and the voltage dividing circuit 5 is connected. A detection circuit 8 detects a predetermined voltage difference between the voltages of the terminals 7 and reduces the conduction of the switch circuit 2. The differentiating circuit 4 is constructed with two elements of a resistor, a coil, and a capacitor as main elements, and FIG. 2 shows a case where a capacitor 9 and a resistor 10 are used, and another case is shown in FIG.

Therefore, the voltage characteristic of the output terminal 6 of the differentiating circuit 4 is as shown in Figure 1D, and the normal differential characteristic E is obtained at the point d (hereinafter referred to as the peak point) and the point d2 (hereinafter referred to as the valley point). different from.

The peak point d, temporally coincides with the peak point a of the storage battery charging voltage characteristic A. The reason why peak point d occurs is not clear, but the voltage across the differentiating circuit 4 increases due to the increase in battery voltage due to characteristic A with respect to characteristic E. This is thought to be due to an increase in the voltage drop across the resistor 10 due to an increase in the inflow current. When the voltage divider circuit 5 is composed of a series circuit of a resistor and a constant voltage element, for example, and the voltage at the intermediate terminal 7 exhibits a constant voltage (reference voltage), the difference voltage between the differential output and the intermediate terminal voltage depends on the differential characteristic 0. . Therefore, the detection time point of the detection circuit 8 is set to a predetermined voltage V3 lower than the voltage V2 at the valley point d2, and the conduction of the switch circuit 2 is reduced by the detection. Further, when the voltage dividing circuit 5 is composed of a series circuit of a plurality of resistors as shown in FIG. 2, and the voltage at the intermediate terminal 7 is proportional to the storage battery voltage, the difference voltage between the differential output and the intermediate terminal voltage is has a characteristic F, and any predetermined differential voltage can be detected. In this case, detection after the peak time is important if the charging capacity is large and the characteristic F
It is preferable that the gradient is large, which makes detection easier. The present invention uses the above-mentioned principle device, and one embodiment thereof will be described below with reference to the drawings. In FIG. 4, reference numeral 11 denotes a transistor inverter, which is connected between DC output terminals 15, 15 of a full-wave rectifier circuit 14, which is connected between AC power supply terminals 12, 12 via a noise filter 13. This inverter 11 connects a series circuit of a primary coil 18 of an oscillation transformer 17 equipped with a resonant capacitor 6 and a collector-emitter of an oscillation transistor 9 to DC output terminals 15, 15.
A series circuit of a feedback coil 20 and a capacitor 21 of the oscillation transistor 17 is inserted between the base and emitter of the oscillation transistor 19, and a bias circuit 22 is provided at the base of the oscillation transistor 19 via the feedback coil 20. ing. The circuit 22 is composed of resistors 23 and 24 connected in series and a control transistor 25 connected in parallel to one of the resistors 24. Oscillation transformer 17-2
The secondary coil 26 is connected to a storage battery 28 via a diode 27, and to the storage battery 28, a differentiation circuit 31 and a resistance voltage divider circuit 32, each of which has a capacitor 29 and a resistor 30 as main elements, are connected in parallel.

33 is a detection circuit that detects a predetermined voltage difference between the terminal 34 of the differentiating circuit 31 and the intermediate terminal 35 of the resistive voltage divider circuit 32 to control the control transistor 25; a first transistor 36 that detects the predetermined voltage difference; , the transistor 36
A second transistor 37 conducts when the transistor 37 conducts, a third transistor 38 operates in reverse with respect to the transistor 37, and a silicon controlled rectifier (hereinafter referred to as SCR) 39 is activated by a rise in the collector voltage when the transistor 38 is cut off. Be prepared.

In addition, a capacitor 40 for maintaining current and a light emitting diode 41 for displaying charging are connected in parallel to the SCR 39,
The short circuit switch 42 of R39 moves with the short circuit switch 43 of the capacitor 29 of the differential circuit 31, and both switches 4
2 and 43 are temporarily opened at the time of starting. The operation in the above configuration will be explained.

Both switches are temporarily closed to release the energy stored in the capacitor 29 and cut off the SCR 39. When the transistor inverter 11 operates in oscillation in this state, the storage battery 28 is charged by the rectified output of the secondary coil 26. In this case, the resistor 24 is short-circuited by the conduction of the control transistor 25, and the base current of the oscillation transistor 9 is large, and the storage battery 28 is charged with a large current. As the charging time elapses, the voltage of the storage battery 28 increases according to the characteristic A, and the voltage of the differential output of the differentiating circuit 31 decreases according to the characteristic D. The characteristic D passes through the valley point d2 and then reaches the peak point d, and at the same time, the characteristic A shows the peak point a. Since the storage battery voltage decreases after that point, the voltage at the divided voltage output terminal 35 also decreases proportionally, but the differential output decreases so much that both terminals 34
, 35 increases as shown by characteristic F, and the first transistor 36 becomes conductive at a predetermined voltage difference V4. Therefore, the second transistor 37 is turned on and the third transistor 38 is turned off, so its collector voltage increases and S
CR39 fires. This SCR39 is capacitor 40
Thus, conduction is maintained, and at the same time, the light emitting diode 41 that has been lit up until now turns off, indicating that the storage battery 28 has been charged to a predetermined charging capacity. Since the control transistor 25 is cut off due to conduction of the SCR 39, a resistor 24 is inserted in the bias circuit 22, and the oscillation transistor 1
The base current of g. The trickle charging current becomes a saddle. As described above, according to the configuration of the present invention, a differentiating circuit is connected in parallel to the storage battery charged by the oscillation output of the inverter, and a predetermined differential voltage after the peak of the differential voltage characteristic appearing in the differentiating circuit output is detected. Since the oscillation output is sharply reduced, the peak point corresponds to the peak point of the charging voltage characteristic of the storage battery, so the detection time of the predetermined differential voltage is after the peak point, and the high current time of the storage battery is large, increasing the charging capacity. Since the charging device according to the present invention can be incorporated into electronic equipment, it is possible to eliminate jogging charging to secure the charging capacity as in the case of secondary charging, and it is also possible to eliminate the noise generated during jogging charging. The usage range of the charging device can be expanded. Furthermore, when the predetermined differential voltage is set to a voltage lower than the trough voltage that occurs before the peak of the differential voltage characteristic, switching the charging current from the large current to the trickle charging current is delayed, and the charging capacity can be further increased.

[Brief explanation of the drawing]

Fig. 1 is a charging characteristic diagram, Fig. 2 is an electric circuit diagram for explaining the principle of the present invention, Fig. 3 is another implementation circuit diagram of the differential circuit, and Fig. 4 is an electric circuit diagram showing one embodiment of the present invention. It is. 11... Inverter, 28... Storage battery, 31... Differential circuit, D... Differential voltage characteristic, d. ......peak point, Q...trough point. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A transistor inverter including an oscillating transistor operated by a rectified voltage of an AC power supply and an oscillating transistor connected to the oscillating transistor, and rectifying the output of the inverter generated in a secondary coil of the oscillating transistor. and a detection circuit that detects a predetermined state of charge of the storage battery, and the output of the detection circuit reduces the base current of the oscillation transistor and reduces the oscillation output of the inverter. A differentiating circuit using two elements of a resistor, a coil, and a capacitor is connected in parallel to the storage battery, and a predetermined differential after the peak of the differential voltage characteristic during battery charging, which appears in the output of the differentiating circuit, is A storage battery charging device characterized in that the voltage is detected by the detection circuit and the oscillation output is sharply lowered. 2. The storage battery charging device according to claim 1, wherein the predetermined differential voltage is a voltage lower than the trough voltage that occurs before the peak of the differential voltage characteristic.