阅读说明：本技术 一种智能充电电路及智能充电方法 (Intelligent charging circuit and intelligent charging method ) 是由 朱洪卫 于 2021-06-15 设计创作，主要内容包括：本发明公开了一种智能充电电路,包括电源电路部分和主控电路部分；电源电路部分包括交流输入电路、直流输出电路；交流输入电路包括降压变换电路和全桥整流滤波电路；直流输出电路包括电源管理芯片U1、开关管Q和升压斩波电路；主控电路部分包括主控芯片U0和主体电路；主体电路包括以一个可控稳压源芯片U2为主体的电压调节电路、以一个双运放芯片U3为主体的电流调节电路和光耦合器U4；主控芯片U0的PWM调制电压信号输出端子、PWM调制电流信号输出端子分别连接主体电路的电压输入端、电流输入端。本发明还公开了基于上述智能充电电路的智能充电方法。本发明能够对多种规格参数的电池充电,充电过程实现充电电压以及最大允许充电电流的自动调节和控制。(The invention discloses an intelligent charging circuit, which comprises a power circuit part and a main control circuit part, wherein the power circuit part comprises a power supply circuit and a power supply circuit; the power supply circuit part comprises an alternating current input circuit and a direct current output circuit; the alternating current input circuit comprises a step-down conversion circuit and a full-bridge rectification filter circuit; the direct current output circuit comprises a power management chip U1, a switching tube Q and a boost chopper circuit; the main control circuit part comprises a main control chip U0 and a main circuit; the main circuit comprises a voltage regulating circuit taking a controllable voltage-stabilizing source chip U2 as a main body, a current regulating circuit taking a double operational amplifier chip U3 as a main body and an optical coupler U4; the PWM modulation voltage signal output terminal and the PWM modulation current signal output terminal of the main control chip U0 are connected to the voltage input terminal and the current input terminal of the main body circuit, respectively. The invention also discloses an intelligent charging method based on the intelligent charging circuit. The invention can charge batteries with various specification parameters, and realizes the automatic regulation and control of the charging voltage and the maximum allowable charging current in the charging process.)

1. An intelligent charging circuit, its characterized in that:

the power supply circuit comprises a power supply circuit part and a main control circuit part; wherein the content of the first and second substances,

the power supply circuit part comprises an alternating current input circuit and a direct current output circuit;

the alternating current input circuit comprises a step-down conversion circuit and a full-bridge rectification filter circuit;

the direct current output circuit comprises a power management chip U1, a switching tube Q and a boost chopper circuit;

the main control circuit part comprises a main control chip U0 and a main circuit;

the main circuit comprises a voltage regulating circuit taking a controllable voltage-stabilizing source chip U2 as a main body, a current regulating circuit taking a double operational amplifier chip U3 as a main body and an optical coupler U4;

the PWM modulation voltage signal output terminal and the PWM modulation current signal output terminal of the main control chip U0 are connected to the voltage input terminal and the current input terminal of the main body circuit, respectively.

2. The intelligent charging circuit of claim 1, wherein:

the input end of the alternating current input circuit is connected with a pair of diodes D1 and D2 in parallel, and is connected with a high-voltage input end HV of a power management chip U1, so that forced starting of the power management chip is realized.

3. The intelligent charging circuit of claim 1, wherein:

the positive electrode input end of the controllable voltage-stabilizing source chip U2 is connected with the positive voltage terminal of the direct current output circuit; the reference input end of the controllable voltage-stabilizing source chip U2 is connected with the positive voltage terminal of the direct current output circuit and two paths of PWM modulation voltage signals from the main control chip U0.

4. The intelligent charging circuit of claim 3, wherein:

and the PWM modulation voltage signal passes through an integral buffer circuit and is used as the reference voltage of a controllable voltage-stabilizing source chip U2.

5. The intelligent charging circuit of claim 1, wherein:

the inverting input end of a double operational amplifier chip U3 of the current regulating circuit is connected with the negative voltage terminal of the direct current output circuit; the positive direction input end of the double operational amplifier chip U3 is connected with a 5V positive power supply, and meanwhile, the double operational amplifier chip also comprises two paths of PWM modulation current signals from the main control chip U0.

6. The intelligent charging circuit of claim 5, wherein:

and the PWM modulation current signal passes through an integral buffer circuit and is used as the reference voltage of a controllable voltage-stabilizing source chip U3.

7. The intelligent charging circuit of claim 1, wherein:

the main control chip U0 is further connected to a battery voltage detection circuit and a thermal protection voltage detection circuit, and a light emitting diode circuit for displaying a charging state.

8. The intelligent charging circuit of any one of claims 1 to 7, wherein:

the main control chip U0 is connected with an external input device through a bidirectional communication interface U5 to set specification parameters of the battery to be charged.

9. An intelligent charging method based on the intelligent charging circuit of claim 8, characterized in that:

the execution steps are as follows:

(1) setting battery specification parameters through external equipment;

(2) the alternating current power supply is switched on, and the power supply management chip U1 is forced to start;

(3) the power management chip U1 drives the switching tube Q to supply power to the battery through the boost chopper circuit;

(4) the main control chip U0 detects the battery voltage;

if the initial voltage of the battery is lower than the preset voltage threshold value of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to turn on a current regulation circuit, and controls a power supply driving circuit to pre-charge the battery at constant low current;

if the initial charging voltage of the battery is greater than the preset voltage threshold of the main control chip U0, or when the voltage of the battery rises above the preset voltage threshold of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to change the output of the current regulating circuit, and controls the power supply driving circuit to charge the battery with the maximum current allowed by the battery;

(5) the main control chip U0 monitors the battery temperature in real time through a thermal protection voltage detection circuit to generate a corresponding thermal protection PWM modulation current signal, and changes the output of a current regulation circuit to reduce the current output of a power supply driving circuit;

(6) when the voltage of the battery rises to be close to the rated voltage, the main control chip U0 outputs a PWM voltage signal to turn on the voltage regulating circuit and control the power supply driving circuit to charge the battery with constant voltage;

(7) when the charging current is smaller than the threshold value set by the main control chip U0, the current regulating circuit outputs low level, and the power management chip U1 turns off the switch tube Q.

10. The intelligent charging method according to claim 9, wherein:

in the step (5), if the battery has a thermal runaway condition, the main control chip U0 starts the automatic protection circuit to cut off the connection between the charging circuit and the battery.

Technical Field

The invention belongs to the technical field of switching power supplies, and particularly relates to an intelligent charging circuit and an intelligent charging method.

Background

With the popularization of electric vehicles, further research is required for a technology of charging a battery.

The first is the adaptability problem of the charger. The specifications of batteries on various electric vehicles are not uniform, and chargers which are individually adapted are often needed, that is, the universality of the chargers is low. New vehicles or new batteries also need to be equipped with new chargers, resulting in increased consumption costs

The second is the battery charging process control problem. The conventional various chargers basically perform charging control in four stages of trickle charging, constant-current charging, constant-voltage charging and charging termination. In terms of the charging characteristics of secondary batteries, especially lithium ion batteries, the internal resistance of the battery is continuously reduced due to the heat generation of the battery during the charging process, the charging current of the battery is further increased, and a more significant thermal effect is generated, so that the output voltage or current of a charger needs to be changed in real time to avoid the thermal runaway phenomenon. Conventional four-phase chargers do not achieve this function.

Disclosure of Invention

The invention aims to solve the problems of insufficient adaptability and low charging efficiency of the conventional charger, and provides an autonomously designed intelligent charging circuit which can set specification parameters of a battery to be charged by external equipment and realize automatic control of thermal balance under the maximum charging efficiency.

The invention provides an intelligent charging circuit, which comprises a power circuit part and a main control circuit part, wherein the power circuit part comprises a power supply circuit and a power supply circuit; the power supply circuit part comprises an alternating current input circuit and a direct current output circuit; the alternating current input circuit comprises a step-down conversion circuit and a full-bridge rectification filter circuit; the direct current output circuit comprises a power management chip U1, a switching tube Q and a boost chopper circuit; the main control circuit part comprises a main control chip U0 and a main circuit; the main circuit comprises a voltage regulating circuit taking a controllable voltage-stabilizing source chip U2 as a main body, a current regulating circuit taking a double operational amplifier chip U3 as a main body and an optical coupler U4; the PWM modulation voltage signal output terminal and the PWM modulation current signal output terminal of the main control chip U0 are connected to the voltage input terminal and the current input terminal of the main body circuit, respectively.

Furthermore, the step-down conversion circuit is composed of a resistor R1, a power frequency transformer T1 and a capacitor C1, wherein the resistor R1 is connected to the input side of the power frequency transformer T1 in parallel, and the capacitor C1 is connected to the output side of the power frequency transformer T1 in parallel.

Furthermore, the boost chopper circuit consists of a first secondary side of the high-frequency pulse transformer T2, a diode D3 and a capacitor C2 connected in parallel with the direct-current output end; the primary winding of the high-frequency pulse transformer T2 is connected between the output end of the full-bridge rectification filter circuit and the drain electrode of the switching tube Q.

Furthermore, a pair of diodes D1 and D2 are connected in parallel at the input end of the alternating current input circuit, and are connected to a high-voltage input end HV of a power management chip U1, so that forced starting of the power management chip is realized.

Further, the positive electrode input end of the controllable voltage-stabilizing source chip U2 is connected with a positive voltage terminal of the direct current output circuit; the reference input end of the controllable voltage-stabilizing source chip U2 is connected with the positive voltage terminal of the direct current output circuit and two paths of PWM modulation voltage signals from the main control chip U0.

Furthermore, the PWM modulation voltage signal passes through an integral buffer circuit to be used as a reference voltage of a controllable voltage-stabilizing source chip U2.

Furthermore, the inverting input end of a double operational amplifier chip U3 of the current regulating circuit is connected with the negative voltage terminal of the direct current output circuit; the positive direction input end of the double operational amplifier chip U3 is connected with a 5V positive power supply, and meanwhile, the double operational amplifier chip also comprises two paths of PWM modulation current signals from the main control chip U0.

Furthermore, the PWM modulation current signal passes through an integral buffer circuit to be used as a reference voltage of a controllable voltage-stabilizing source chip U3.

Further, the main control chip U0 is also connected to a battery voltage detection circuit, a thermal protection voltage detection circuit, and a light emitting diode circuit for displaying a charging state.

Further, the main control chip U0 is connected to an external input device through the bidirectional communication interface U5, so as to realize specification selection of the battery to be charged.

Furthermore, a second secondary side T3 of the high-frequency pulse transformer T2 is connected to a power supply terminal of the power management chip U1 through a rectification voltage stabilizing circuit, so as to provide a stable working power supply for the U1.

Further, a third secondary side T4 of the high-frequency pulse transformer T2 provides working voltage for the main control chip U0, the controllable regulator chip U3 and the bidirectional communication interface U5 through the regulator circuit.

The invention also provides an intelligent charging method, which comprises the following steps:

(1) setting battery specification parameters through external equipment;

(2) the alternating current power supply is switched on, and the power supply management chip U1 is forced to start;

(3) the power management chip U1 drives the switching tube Q to supply power to the battery through the boost chopper circuit;

(4) the main control chip U0 detects the battery voltage;

if the initial voltage of the battery is lower than the preset voltage threshold value of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to turn on a current regulation circuit, and controls a power supply driving circuit to pre-charge the battery at constant low current;

if the initial charging voltage of the battery is greater than the preset voltage threshold of the main control chip U0, or when the voltage of the battery rises above the preset voltage threshold of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to change the output of the current regulating circuit, and controls the power supply driving circuit to charge the battery with the maximum current allowed by the battery;

(5) the main control chip U0 monitors the battery temperature in real time through a thermal protection voltage detection circuit to generate a corresponding thermal protection PWM modulation current signal, and changes the output of a current regulation circuit to reduce the current output of a power supply driving circuit;

(6) when the voltage of the battery rises to be close to the rated voltage, the main control chip U0 outputs a PWM voltage signal to turn on the voltage regulating circuit and control the power supply driving circuit to charge the battery with constant voltage;

(7) when the charging current is smaller than the threshold value set by the main control chip U0, the current regulating circuit outputs low level, and the power management chip U1 turns off the switch tube Q.

Further, in the step (5), if the battery has a thermal runaway condition, the main control chip U0 starts an automatic protection circuit to cut off the connection between the charging circuit and the battery.

Compared with the charger in the prior art:

the intelligent charging circuit has a simple structure and can be adapted to batteries with various specification parameters. In the charging process, the charging voltage and the allowed maximum charging current of the battery are automatically regulated and controlled, and the charging is rapid. When the maximum charging current of the battery is automatically regulated and controlled, the battery overheating protection is realized, and no potential safety hazard exists.

Drawings

FIG. 1 is a block diagram of the intelligent charging circuit of the present invention;

FIG. 2 is a schematic diagram of the operation of the power circuit portion of the present invention;

FIG. 3 is a wiring diagram of a main control chip according to the present invention;

fig. 4 is a schematic diagram of the operation of the main circuit of the main control circuit part of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

as shown in fig. 1, the intelligent charging circuit of the present invention includes a power circuit portion and a main control circuit portion.

The power supply circuit part comprises an alternating current input circuit and a direct current output circuit. The working principle diagram is shown in figure 2.

The AC input circuit adopts a structure with a BUCK conversion circuit (BUCK) and a full-bridge rectification filter circuit. In fig. 2, a resistor R1, a power frequency transformer T1, and a capacitor C1 form a BUCK conversion circuit, the resistor R1 is connected in parallel to the input side of the power frequency transformer T1, and the capacitor C1 is connected in parallel to the output side of the power frequency transformer T1.

The direct current output circuit comprises a power management chip U1, a switching tube Q and a Boost chopper circuit (Boost). The Boost circuit is composed of a first secondary side of a high-frequency pulse transformer T2, a diode D3 and a capacitor C2 connected in parallel to a direct current output end. The primary winding of the high-frequency pulse transformer T2 is connected between the output end of the full-bridge rectification filter circuit and the drain electrode of the switching tube Q.

The power management chip U1 may be selected from a model commonly used in the art, such as PN 8273. The power driving chip U1 performs PWM control on the switching tube Q, and outputs the PWM control to the outside through the high-frequency pulse transformer T2. The illustrated switching transistor Q is an N-type MOS transistor.

The input end of the alternating current input circuit is connected with a pair of diodes D1 and D2 in parallel, and is connected with a high-voltage input end HV of a power management chip U1, so that forced starting of the power management chip is realized.

The second secondary side T3 of the high-frequency pulse transformer T2 is connected to a power supply terminal of the power management chip U1 through a rectification voltage stabilizing circuit, and provides a stable working power supply for the U1. Meanwhile, the second secondary side T3 is connected to the voltage feedback terminal DRMG of the power management chip through a voltage dividing resistor, and outputs a compensation current signal through the CS terminal inside the U1 as a line voltage compensation detection signal.

The third secondary side T4 of the high frequency pulse transformer T2 may be used as an input terminal of the 5V operating voltage stabilizing circuit inside the intelligent charging circuit of the present invention. This can be done by a person skilled in the art according to the prior art.

The main control circuit part comprises a main control chip U0 and a main body circuit. In the embodiment of the invention, the main control chip adopts a single chip microcomputer packaged by SOP 20.

The main peripheral wiring of the master control chip U0 is shown in fig. 3. The main control chip U0 is connected to an external input device (e.g., PC) through a bidirectional communication interface U5 (e.g., MAX485) to realize specification selection of the battery to be charged.

The main control chip U0 is also connected with a battery voltage detection circuit, a thermal protection voltage detection circuit, and a light emitting diode circuit for displaying the charging state.

The PWM modulation voltage signal output terminal and the PWM modulation current signal output terminal of the main control chip U0 are connected to the voltage input terminal and the current input terminal of the main body circuit, respectively.

The operation principle of the main circuit is shown in fig. 4, and the main circuit comprises a voltage regulating circuit taking a controllable voltage-stabilizing source chip U2(TL431) as a main body, a current regulating circuit taking a double-operational amplifier chip U3(LM358) as a main body and an optical coupler U4.

The positive terminal of the voltage regulation circuit controllable voltage-stabilizing source chip U2 is connected with the positive voltage terminal (B +) of the direct current output circuit, and the reference input terminal of the controllable voltage-stabilizing source chip U2 is connected with the positive voltage terminal of the direct current output circuit and two paths of PWM modulation voltage signals from the main control chip U0. The PWM modulation voltage signal is used as the reference voltage of the controllable voltage-stabilizing source chip U2 through an integral buffer circuit formed by a capacitor C3, a resistor R1 and a capacitor C4, so that the output current of the controllable voltage-stabilizing source chip U2 is regulated, the output current change of the controllable voltage-stabilizing source chip U2 is fed back to a feedback input access point A of a power management chip U1 through an optical coupler U4, the power management chip U1 performs PWM duty ratio control on a switch tube Q, and the regulation of the output voltage of the power circuit part is completed.

The inverting input end of the double operational amplifier chip U3 of the current regulating circuit is connected with the negative voltage terminal (B-) of the direct current output circuit. The positive input end (current feedback input end) of the dual operational amplifier chip U3 is connected with a 5V positive power supply, and meanwhile, the dual operational amplifier chip also comprises two paths of PWM modulation current signals from the main control chip U0. The PWM modulation current signal is used as the reference voltage of a controllable voltage-stabilizing source chip U3 through an integral buffer circuit consisting of a capacitor C5, a resistor R2 and a capacitor C6, the output low level of the controllable voltage-stabilizing source chip U3, the change of the output voltage of the controllable voltage-stabilizing source chip U3 is fed back to a feedback input access point A of a power management chip U1 through the conduction current of an optical coupler U4, the power management chip U1 performs PWM control on a switch tube Q, and therefore the adjustment of the output current of the power circuit part is completed.

A diode D4 is connected in series between the controlled regulator chip U3 and the optocoupler U4 in reverse to isolate the voltage regulation circuit from the current regulation circuit.

The intelligent charging circuit of the invention controls the charging process of the battery as follows:

and setting specification parameters of the battery to be charged through the external equipment.

When a 220V alternating current power supply is switched on, a half-bridge circuit formed by diodes D1 and D2 supplies power to a high-voltage input end HV of a power management chip U1, and the power management chip U1 is forced to be started.

An alternating current power supply is rectified and filtered by an alternating current input circuit and then loaded to the switching tube Q through the high-frequency pulse transformer T2, the switching tube Q is driven by the power management chip U1 to supply power (B +, B-) to the outside through the first secondary side of the high-frequency pulse transformer T2, and a battery is charged.

Meanwhile, a second secondary side T3 of the high-frequency pulse transformer T2 is connected to a power supply terminal of the power management chip U1 through a rectification voltage stabilizing circuit, and a stable working power supply is provided for the U1. Meanwhile, a second secondary side T3 of the high-frequency pulse transformer T2 is connected to a voltage feedback terminal DRMG of the power management chip through a voltage dividing resistor to serve as a line voltage compensation detection signal, and a compensation current signal is output through a CS terminal in the U1; the third secondary side T4 of the high-frequency pulse transformer T2 provides working voltage for the main control chip U0, the controllable voltage-stabilizing chip U3 and the bidirectional communication interface U5 through the voltage-stabilizing circuit.

The main control chip U0 detects the battery voltage to determine the charging mode. If the initial voltage of the battery is lower than the preset voltage threshold of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to turn on the current regulation circuit, and the power supply driving circuit is controlled to pre-charge the battery at constant low current.

When the voltage of the battery rises above the preset voltage threshold of the main control chip U0, the main control chip U0 outputs a PWM modulation current signal to change the output of the current regulating circuit, and the power supply driving circuit is controlled to charge the battery with the maximum current (C rate between 0.2 and 1.0) allowed by the battery. And directly starting high-current charging if the initial charging voltage of the battery is greater than the preset voltage threshold.

In the large-current charging stage, the heat productivity of the internal resistance of the battery is increased, the temperature of the battery is increased, and meanwhile, the activity of the material of the battery is increased, so that the internal resistance of the battery is further reduced, and the charging current is further increased. The relatively fast temperature rise process tends to cause the cell temperature to exceed the structural tolerance of the cell itself, causing severe damage. Therefore, the main control chip U0 monitors the battery temperature in real time through the thermal protection voltage detection circuit to generate a corresponding thermal protection PWM modulation current signal, and changes the output of the current regulation circuit to reduce the current output of the power driving circuit, thereby achieving thermal balance. If the battery has a thermal runaway condition, the main control chip U0 starts an automatic protection circuit to cut off the connection between the charging circuit and the battery.

When the main control chip U0 determines that the battery voltage rises to near the rated voltage (voltage selected by the external device), the main control chip U0 outputs a PWM modulated voltage signal to turn on the voltage regulating circuit, and controls the power driving circuit to charge the battery with a constant voltage (battery rated voltage).

In the constant voltage charging process, the battery charging current is gradually reduced, the voltage on a resistor R3 at the inverting input end in the current regulating circuit is reduced, when the charging current is smaller than the set threshold value of the main control chip U0, the current regulating circuit outputs low level, the conducting current of the optical coupler U4 feeds back the output voltage change of the controllable voltage-stabilizing source chip U3 to the feedback input access point A of the power management chip U1, the power management chip U1 turns off the switch tube Q, and the charging is finished.

The intelligent charging circuit disclosed by the invention is simple and practical in structure, realizes automatic regulation of the charging voltage and the charging current of the battery in the whole charging process, and improves the charging efficiency on the premise of safe charging.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

The present invention is not limited to the above description of the embodiments, and those skilled in the art should, in light of the present disclosure, appreciate that many changes and modifications can be made without departing from the spirit and scope of the invention.