JPS63294228A - Charging circuit - Google Patents

Abstract

PURPOSE:To charge a battery stably by controlling the phase of charging currents according to the value of charging currents and keeping charging currents constant. CONSTITUTION:An output from a step-down transformer 22 stepping down a commercial input power 21 is fed to a battery 25 to be charged through a rectifier circuit 23 and a phase control circuit 24. Charging currents to the battery 25 to be charged are detected by a current detecting sensor 26, and the phase control circuit 24 is controlled by a constant-current control circuit 27 so that charging currents are brought to specified constant currents on the basis of a value detected by the sensor 26.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a charging circuit for photoelectrically charging a battery with a set and constant charging current.

(Conventional technology) An example of a conventionally widely known charging circuit is shown in FIG.

The circuit system shown in the figure is called the "Do1" collar type.
The voltage of the commercial input power is stepped down by the transformer T, converted to DC by the rectifier bridge Ref', and smoothed by the capacitor C1.
The current determined by the emitter voltage and resistor R3 is
The battery B to be charged is charged by flowing through the transistor Q1.

This method has no drawbacks such as noise generation because the charging current is pure direct current, but when a large current is passed during charging, the transistor Q1 generates a very large amount of heat, and it is also sensitive to battery voltage fluctuations and input voltage fluctuations. On the other hand, the heat generation of the transistor Q1 fluctuates greatly, which poses a practical problem.

Next, FIG. 10 shows another example of a conventional charging circuit.

This system is a self-excited chopper type constant current charging circuit, and by controlling the control transistor (or thyristor control element, etc., although not shown) on and off,
It is also called a switching type, which attempts to keep the current or voltage to the charged battery B constant by chopping the input voltage.

That is, in the J circuit shown in FIG. 10, the commercial power source whose voltage is stepped down by the transformer T is converted to DC by the rectifier bridge Ref, and smoothed by the =1 capacitor C1. So()
The transistor Q1 is a control switching element,
Inductance 1 and capacitor C3 function as a smoothing filter. In addition, the coils A to D1 have a function of effectively flowing the energy stored in the inductance to the load. In addition, a boriko, -mu VR1, which detects the charging current to battery B,
A charging current control circuit including transistors Q3, 02, etc. controlled by the output of the amplifier A is provided to the amplifier that compares the voltage Vr corresponding to this charging current with the base t\=voltage VZ.

11(a), (11), and (C) show the waveforms of the output voltage, detection voltage Vr, reference voltage Vz, and output current in the circuit of FIG. 10, respectively.

The voltage Vr detected by the charging current detection volume VR is compared with the reference voltage Vz by the amplifier 8, and its output is used to drive the transistors Q3. The conduction of transistor Q1 is controlled via Q2.

Therefore, if the output current 1o is now high, the output of the amplifier A decreases, and the transistor Q1 turns off.As a result, the energy stored in the inductance flows to the load through the diode D1.

By repeating such operations, a constant current charging output can be obtained.

This method can reach an efficiency of 90 to 95%, making it possible to obtain an extremely efficient, compact, and high-power constant current charging circuit. The output is stable against fluctuations, but
It is disadvantageous in that it is expensive and tends to generate noise as shown in FIG. 11 (C1) due to the switching operation.

(Object of the Invention) The present invention has been made in view of the above points, and it is capable of stably charging a battery with a constant charging current even if the input power supply voltage or battery assignment changes. The purpose of the present invention is to provide an inexpensive charging circuit that can perform high-speed charging and generate less heat and noise.

(Structure of the Invention) The present invention includes a step-down transformer that steps down the input power supply voltage, a rectifier circuit that rectifies the output of this step-down transformer,
The charging circuit includes a current control circuit unit that controls the output current of the rectifier circuit to control the charging current to the battery to be charged, and a current detection sensor 1 that detects the charging current flowing to the battery to be charged. and the current control circuit section is provided with a phase control circuit that controls the phase of the charging current according to the value detected by the current detection sensor to keep the charging current constant. .

With this configuration, the phase of the charging output is controlled according to the detected value of the charging current, thereby enabling constant current charging.

(Embodiment) FIG. 1 shows the basic block configuration of the charging circuit of the present invention.

-〇- This charging circuit includes a step-down transformer 22 that steps down the voltage of the commercial input type 8!21, a rectifier circuit 23 that rectifies the output of this step-down transformer 22, and a rectifier circuit 23 that controls the output current of the rectifier circuit 23 to The phase control circuit 24 is equipped with a current control circuit section for controlling the charging current to the battery 25 and a phase control circuit 24 for controlling the charging current to the battery 25, and a current detection circuit for detecting the charging current to the battery 25 so that the phase control circuit 24 is phase-controlled to a constant current. It is provided with a sensor 26 and a constant current control circuit 27 that controls the phase control circuit 24 so that the charging current becomes a predetermined constant current based on the value detected by the sensor 26.

FIG. 2 shows a concrete first embodiment of the present invention.

In FIG. 2, blocks 21 to 27 are equivalent to those in FIG. 1. 28 is a charging circuit for 70-ting, 29 is a control circuit power supply, 30 is a V-1 conversion circuit, 31 is a constant current setting circuit, 32 is a zero reset and triangular wave generation circuit, 33
is a comparison circuit, 34 is an output circuit, 35 is a display circuit, 36 is a temperature sensor circuit, 37 is a comparator, 38 is a timer circuit,
39 is a reset circuit.

And, Juki V-1 conversion circuit 30, constant current setting circuit 31
, zero reset and triangular wave generation circuit 32, comparison circuit 33
and the output circuit 34 constitute a constant current control circuit 27, and the phase control circuit 24 and the constant current control circuit 2
A current control circuit section for controlling the charging current is provided by 7 or the like.

The battery to be charged (B) 25 includes a thyristor (SCR) which is a control element of the phase control circuit 240 and a current detection sensor (R5).
) 26 and 9+1, and is connected to the output end of the rectifier circuit 23.

In addition, the comparison signal input @(■ pin) of the V-1 conversion circuit 30 is inputted with both asthmatic currents of the current detection sensor R5, and the transistor 02 of the output circuit 34 is connected to the phase control circuit 24 through the display circuit 35. The control thyristor G1 is connected to the transistor Q1 forming the circuit.

Furthermore, a signal from a temperature sensor circuit 36 that detects the temperature of battery B is input to the - input of the comparator 7, and the output of the comparator 37 and the timer circuit 38 are connected to the reset 1 input.
The output circuit 34 is controlled by the reset circuit 39, and battery charging is controlled by the temperature and timer.

Briefly explaining the operation of the constant current control circuit 27 shown in FIG. 2, the charging current detected by the current detection sensor °R5 is converted into a voltage, and then converted into a current by the V-1 conversion circuit 30. At this time, the charging 11i of the electrolytic capacitor C1 is determined by the volume VR of the constant current setting circuit 31, and the amount of discharge is determined by the output current of the VI conversion circuit 30.

A triangular wave is generated by the zero reset and triangular wave generation circuit 32 at the same frequency as the oscillation frequency of the commercial power supply frequency,
It is input to the (2) bin of IC2 of the comparator circuit 33. This input is compared with the voltage across the capacitor C1, and the voltage across the capacitor C1 is compared.
1 voltage is high, the output of the comparator circuit 33 is 11''], and the transistor Q2 of the output circuit 34 is turned on, so
The transistor Q1 of the phase control circuit 24 also passes the gate current of the thyristor ONL, and the thyristor is ONL, -
〇 - Charge battery B. Conversely, when the capacitor C1 voltage is lower than the triangular wave voltage, the thyristor is turned off.

Thus, the phase of the thyristor is controlled so that the voltage at point (1) in FIG.

A time chart of the above operation is shown in FIG. 3 using the voltages at each point in FIG. 2.

According to the above embodiment, since control is performed every time the power supply frequency is recycled, the response speed to load fluctuations and input power fluctuations is not only faster than that of conventional ON/OFF control methods, but also in one cycle. It has the advantage that large current does not flow.

Furthermore, if the current setting is set to the maximum number of batteries in the constant current setting circuit 31, it becomes possible to charge from one battery to the maximum number of batteries with a constant current, making it possible to share charging equipment. .

In addition, even if the battery is short-circuited, constant current charging is used, so the charging current does not increase compared to a conventional charging circuit with only one lance, so battery deterioration can be stopped and damage caused by heat generation of the circuit can be prevented.

In addition, since there is no variation in charging current due to input voltage fluctuations,
Thailand? - The capacity of the battery can be maintained even after charging.

Furthermore, since it is constant current charging, the battery voltage rise curve,
The battery temperature curve becomes constant, so the so-called -
Rapid charge control such as ΔV and ΔT control can be easily performed.

Next, FIG. 4 shows a second embodiment of the present invention. This embodiment detects the voltage and temperature of the battery and has both voltage control and temperature control functions (71).The configuration and operation of the constant current control circuit 27 are the same as in the above embodiment.

The current control circuit section 40 compares the reference voltage set by resistors R18 and R19 with the battery voltage at [C3], and when the battery voltage exceeds the reference voltage, the output of IC3 becomes 1'l-IJ, and the transistor Q5 ONL, the output circuit 34 is stopped and the thyristor is turned off. In addition, the resistor R21
The series circuit of the diode DIO and the diode DIO is a hysteresis generating circuit for IC3.

On the other hand, the temperature control circuit 41 includes a resistor R22 and a resistor R23.
The reference voltage set by temperature sensor R16, diode D7. Temperature sensor R16 consisting of a series circuit of D8 and voltage are compared and it is determined that temperature sensor R16 is placed in close contact with battery B. Then, the output of the IC4 becomes [H-1], the transistor 06 becomes ONL, and the υ iris of the phase control circuit 24 is set to 01F as in the case of the voltage control circuit 40 described above. Note that the series circuit of resistor R25 and diode D11 is a hysteresis generating circuit for IC4.

In this second embodiment, by providing the voltage control circuit 40, Ff, 1 car 1 becomes constant on the battery voltage, so that it is possible to stabilize the control voltage and equalize the charging capacity of the battery.

FIG. 5 shows a third embodiment of the invention. In this embodiment, the temperature sensor is replaced with a PTCW master, and this is connected in series with the resistor R10 and Polycomb VR, which is the charging circuit for the capacitor c1 of the constant current setting circuit 31.
This makes it possible to control battery temperature without using a special control circuit.

The thermistor is provided in close contact with the battery B so that the battery temperature can be easily detected. Although a PTC thermistor has a small resistance value at room temperature, its rise characteristic is steep. Therefore, normal constant current charging to the capacitor C1 is possible near room temperature, and by setting the control temperature to a state where the thermistor's rising temperature is steep, the thermistor's resistance value will decrease as the battery temperature rises. As a result, the charging current to the capacitor C1 decreases, and as a result, the voltage at point 61 in FIG. However, the charging current to battery B is reduced, and the temperature of the battery can be controlled.

FIG. 6 shows a fourth embodiment of the invention. In this embodiment, a soft start circuit 42 is provided as a part of the constant current control circuit 27. That is, by adding f1 to the capacitor C1, a sonoto start circuit 42 with a large time constant consisting of a resistor R19 and a capacitor C6, (d)
The thermal voltage is raised slowly, thereby gradually increasing the charging current to the battery by 15%.

FIG. 7 shows each voltage waveform of the circuit of this embodiment.

As shown in the figure, the charging current does not flow immediately after the power is turned on, but gradually begins to flow.

In this fourth embodiment, by gradually increasing the charging current when power is input, the feedback is delayed by at least one cycle, which prevents inrush current, prevents destruction of thyristors and rectifier bridges, and prevents current fuses (not shown in the figure). figure)
Helps prevent destruction.

FIG. 8 shows the FIG. 5 embodiment of the present invention. In this embodiment, an inductance [is connected in series with the thyristor of the phase control circuit 24, that is, in series with the battery B. The other configurations are the same as those of the first embodiment.

By providing the inductance L in this manner, the rising waveform when the thyristor is turned on can be blunted, and the effective current can be reduced.

Therefore, in this fifth embodiment, it is possible to downsize the transformer, prevent the thyristor from generating heat, and prevent the battery from deteriorating.

(Effects of the Invention) As described above, according to the present invention, the current control circuit section is provided with a phase control circuit that performs phase control on the charging current according to the charging N current detection value by the current detection sensor, and keeps the charging current constant. Since the battery is equipped with a constant current, the battery can be charged with a constant current.
Moreover, it is stable against load fluctuations, power supply voltage fluctuations, etc., and can reduce heat generation and noise generation. therefore,
It is possible to solve problems such as heat generation of control elements, load fluctuations, and input fluctuations in the conventional dropper method, as well as problems such as cost and noise in the switching (chopper) method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the charging circuit of the present invention, FIG. 2 is a circuit configuration diagram showing a specific first embodiment of the present invention, and FIG. 3 is a voltage waveform of each part of the circuit in FIG. 4 is a circuit diagram showing a second embodiment of the present invention, FIG. 5 is a circuit diagram showing a third embodiment of the present invention, and FIG. 6 is a circuit diagram showing a fourth embodiment of the present invention.
FIG. 7 is a voltage waveform diagram of each part of the circuit shown in FIG. 6, FIG. 8 is a circuit diagram showing the fifth embodiment of the present invention, and FIG. 9 is an example of a conventional charging circuit. FIG. 10 is a circuit diagram showing another conventional example, FIG. 11(a)
(b) and (C) are the output voltages of the circuit in Figure 10, respectively;
3 is a waveform diagram of detection, reference voltage, and output current; FIG. 21... Input power supply, 22... Step-down transformer, 23.
... Rectifier circuit, 24 ... Phase control circuit, 25 ... Battery, 26 ... Current detection sensor, 27 ... Constant current control circuit, 30 ... V-1 conversion circuit, 31 ... Constant current setting circuit, 32... Zero threshold 1~ and triangular wave generation circuit, 33... Comparison circuit, 34... Output circuit, R16.
...Temperature sensor (thermistor), 42...Soft start circuit, C1...Electrolytic capacitor, 1...Inductance, B...Battery. Procedural amendment (voluntary) July 14, 1988

Claims (1)

[Claims] 1. A step-down transformer that steps down the input power supply voltage, a rectifier circuit that rectifies the output of the step-down transformer, and a control current that controls the output current of the rectifier circuit to control the charging current to the battery to be charged. A charging circuit comprising a current control circuit section includes a current detection sensor for detecting a charging current flowing to a battery to be charged, and a charging current is supplied to the current control circuit section according to a value detected by the current detection sensor. A charging circuit characterized by being provided with a phase control circuit that controls the phase and makes the charging current constant. 2. The phase control circuit consists of a V-I conversion circuit that converts the voltage detected by the current detection sensor into a current, and a constant current circuit that discharges the electric charge stored in the electrolytic capacitor at a constant rate and charges the electrolytic capacitor with a constant current. , a triangular wave generating circuit that generates a triangular wave every cycle of the input power frequency; and a comparison circuit that compares the electrolytic capacitor voltage with the triangular wave generating circuit voltage and generates a phase control output. The charging circuit described in item 1. 3. The charging circuit according to claim 1, comprising a voltage control circuit that detects the battery voltage, compares the detected battery voltage with a reference voltage, and controls the output of the phase control. . 4. Claim 1, characterized in that a temperature-dependent resistance element is provided in the phase control circuit, and the resistance element is used as a temperature detection element of the battery to control the battery temperature.
Charging circuit described in section. 5. The charging circuit according to claim 1, further comprising a soft start circuit in the phase control circuit. 6. The charging circuit according to claim 1, characterized in that an inductance is connected in parallel with the battery.