CN202206178U - AC/DC charging power supply - Google Patents

Abstract

The utility model relates to an AC/DC charging power supply, including an AC/DC conversion circuit, the power supply terminal of the AC/DC conversion circuit is connected to 220V alternating current, the AC/DC conversion circuit is connected to a lithium battery pack through a charging judgment control circuit, and the charging judgment control circuit is connected to the AC/DC conversion circuit through a constant current control circuit. The utility model has a small volume, which is 1/3 or 1/2 of a power supply with the same power; the conversion efficiency is high, and the conversion efficiency can reach 90% within the entire input voltage range, while the general power supply can only reach 85%; currently, the battery is charged with a current of 0.5C, and a one-time charging takes 4 hours to complete, while the utility model charges at three times the speed, and the charging is completed within 2.5 hours.

Description

AC/DC charging power supply

technical field

The utility model relates to the field of charging power sources, in particular to an AC/DC charging power source.

Background technique

At present, lithium battery packs have been widely used in the market, and the disadvantage of slow charging time of large-capacity lithium battery packs has become more and more prominent. In order to speed up the charging time, the battery charger becomes the key to the charging speed. So it is very important to design a charger with high output power and conversion efficiency and small size.

Utility model content

The purpose of the utility model is to provide an AC/DC charging power source with small volume, high output power and conversion efficiency, and capable of fast charging a large-capacity lithium battery pack. the

In order to achieve the above purpose, the utility model adopts the following technical solutions: an AC/DC charging power supply, including an AC/DC conversion circuit, the power supply terminal of the AC/DC conversion circuit is connected to 220V alternating current, and the AC/DC conversion circuit is controlled by charging judgment The circuit is connected with the lithium battery pack, and the charging judgment control circuit is connected with the AC/DC conversion circuit through the constant current control circuit.

It can be seen from the above technical scheme that the volume of the utility model is small, and its volume is 1/3 or 1/2 of the power supply of the same power; the conversion efficiency is high, and the conversion efficiency can reach 90% in the entire input voltage range, while the general power supply Only 85% can be achieved; now the battery is charged with a current of 0.5C, and one-time charging takes 4 hours to complete, while the utility model is charged at three times the speed, and the charging is completed within 2.5 hours.

Description of drawings

Fig. 1 is a circuit block diagram of the utility model.

Detailed ways

An AC/DC charging power supply, comprising an AC/DC conversion circuit 1, the power supply terminal of the AC/DC conversion circuit 1 is connected to 220V alternating current, the AC/DC conversion circuit 1 is connected to a lithium battery pack through a charging judgment control circuit 4, and the charging judgment control circuit The circuit 4 is connected with the AC/DC conversion circuit 1 through the constant current control circuit 2, as shown in FIG. 1 . AC/DC conversion circuit 1 converts 220V AC power into DC voltage. In order to reduce the volume of AD/DC conversion circuit 1, a single-ended forward power conversion method is used; When the lithium battery pack is fully charged, the output is in a constant current mode to meet the charging requirements of the battery in a constant current state; the charging judgment control circuit 4 can directly stop charging after the lithium battery pack is fully charged, so as to avoid overcharging of the lithium battery pack. After displaying the state of the green light, the lithium battery pack is still being charged, so long-term charging may cause overcharging of the battery, which will bring a series of potential safety hazards, and the charging judgment control circuit 4 directly uses an electronic switch to cut off the charging of the lithium battery pack. The charging of the battery pack achieves a safe charging process.

As shown in FIG. 1 , the AC/DC conversion circuit 1 is connected to the protection circuit, and the charging judgment control circuit 4 is connected to the charging display circuit 3 . The charging display circuit 3 shows the charging state of the lithium battery pack, the red light is on during constant current charging, the yellow light is on during constant voltage charging, and the green light is on when charging is completed. The protection function of the protection circuit is the temperature protection function and the input power protection function. The temperature protection function is to prevent the charging power supply from being damaged due to excessive operating temperature. High and damage the charging power supply.

As shown in Figure 1, the AC/DC conversion circuit 1 is composed of an input rectification filter circuit, a PWM pulse width controller, a power switch tube, an output rectification filter circuit, an output voltage sampling circuit and a constant voltage control circuit. The power supply terminal of the input rectification filter circuit is connected to 220V AC, the output end of the input rectification filter circuit is connected to the input end of the PWM pulse width controller, and the output end of the PWM pulse width controller is connected to the input end of the output rectification filter circuit through a power switch tube , the output end of the output rectification filter circuit is connected to the input end of the charging judgment control circuit 4, the output end of the charging judgment control circuit 4 is connected to the input end of the output voltage sampling circuit, and the output end of the output voltage sampling circuit is connected to the constant voltage control circuit. The input terminals are connected, and the output terminal of the constant voltage control circuit is connected with the input terminal of the PWM pulse width controller.

AC/DC conversion circuit 1 converts 220V AC power into 310V DC power through the input rectification filter circuit, controls the power switch tube through the PWM pulse width controller, makes the transformer step down and outputs pulsating DC power, and obtains the DC power used for charging through the output rectification filter circuit Voltage. The voltage is controlled by the output voltage sampling circuit and then compared and amplified to obtain a control signal to control the PWM pulse width controller to adjust the conduction pulse width of the power switch tube to achieve a constant voltage DC voltage. AD/DC conversion circuit 1 adopts a single-ended forward conversion method. The advantage of the forward energy transfer circuit is that the ripple at the output end is lower than that of the flyback type. The circuit is simple, and each output only needs one secondary coil and two coils. Only a diode, an inductor, and a capacitor are a suitable choice for a power supply with size requirements. The PWM pulse width controller chooses the chip UC3843, which has the advantages of adjustable output frequency, wide operating voltage range, few peripheral components, and simple external circuit assembly, and is suitable for single-ended forward conversion.

As shown in Figure 1, described constant current control circuit 2 is made up of output current sampling circuit and control circuit, and the output terminal of described charge judgment control circuit 4 is connected with the input terminal of output current sampling circuit, and the output terminal of output current sampling circuit The output end is connected with the input end of the control circuit, and the output end of the control circuit is connected with the input end of the PWM pulse width controller. Lithium battery packs have a constant current charging process when charging, and need to reach a state where the current remains constant and the voltage changes. Through the output current sampling circuit, when the current reaches a certain value, the control circuit starts to work. By controlling the PWM pulse width controller of the previous stage to adjust the conduction of the power switch tube, the pulse width achieves the effect of constant current, and the constant current control takes precedence over Constant pressure control.

As shown in Figure 1, the protection circuit is composed of a temperature sampling circuit, a temperature protection circuit, an input current sampling circuit and a power protection circuit, the output of the temperature sampling circuit is connected to the input of the temperature protection circuit, and the temperature protection The output end of the circuit is connected to the input end of the PWM pulse width controller, the output end of the input rectification filter circuit is connected to the input end of the input current sampling circuit, and the output end of the input current sampling circuit is connected to the input end of the power protection circuit , the output terminal of the power protection circuit is connected with the input terminal of the PWM pulse width controller. The temperature sampling circuit uses the temperature switch to sample the temperature of the radiator of the charging power supply. When the temperature reaches 95°C, the temperature switch opens and the temperature protection circuit starts to work. When the switch closes the temperature, the whole charging power supply can resume working. The power protection circuit is mainly to protect the entire power conversion part from working under the rated power, so that it will not cause thermal breakdown damage, through the sampling of the input current sampling circuit, when the current reaches a certain value, the power protection circuit starts to work, through the PWM pulse The wide controller controls to turn off the power switch tube, so that the whole power conversion part stops working.

Claims (5)

1. AC/DC charge power supply; It is characterized in that: comprise AC/DC translation circuit (1); The power supply termination 220V alternating current of AC/DC translation circuit (1); AC/DC translation circuit (1) judges that through charging control circuit (4) links to each other with the lithium battery group, and charging judges that control circuit (4) links to each other with AC/DC translation circuit (1) through constant-current control circuit (2).

2. AC/DC charge power supply according to claim 1 is characterized in that: described AC/DC translation circuit (1) links to each other with protective circuit, and charging judges that control circuit (4) links to each other with charging display circuit (3).

3. AC/DC charge power supply according to claim 1; It is characterized in that: described AC/DC translation circuit (1) is made up of input rectifying filter circuit, PWM pulse width controller, power switch pipe, output rectifier and filter, output voltage sampling circuit and constant-voltage control circuit; The power supply termination 220V alternating current of described input rectifying filter circuit; The output of input rectifying filter circuit links to each other with the input of PWM pulse width controller; The output of PWM pulse width controller links to each other with the input of output rectifier and filter through power switch pipe; The output of output rectifier and filter judges that with charging the input of control circuit (4) links to each other; Charging judges that the output of control circuit (4) links to each other with the input of output voltage sampling circuit, and the output of output voltage sampling circuit links to each other with the input of constant-voltage control circuit, and the output of constant-voltage control circuit links to each other with the input of PWM pulse width controller.

4. AC/DC charge power supply according to claim 3; It is characterized in that: described constant-current control circuit (2) is made up of output current sample circuit and control circuit; Described charging judges that the output of control circuit (4) links to each other with the input of output current sample circuit; The output of output current sample circuit links to each other with the input of control circuit, and the output of control circuit links to each other with the input of PWM pulse width controller.

5. AC/DC charge power supply according to claim 3; It is characterized in that: described protective circuit is made up of temperature sampling circuit, temperature protection circuit, input current sample circuit and power protecting circuit; The output of described temperature sampling circuit links to each other with the input of temperature protection circuit; The output of temperature protection circuit links to each other with the input of PWM pulse width controller; The output of described input rectifying filter circuit links to each other with the input of input current sample circuit, and the output of input current sample circuit links to each other with the input of power protecting circuit, and the output of power protecting circuit links to each other with the input of PWM pulse width controller.

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