CN110696672B

CN110696672B - System for realizing rapid charging of power battery

Info

Publication number: CN110696672B
Application number: CN201911087007.0A
Authority: CN
Inventors: 张江林; 张绍全; 庄慧敏; 王震; 谢晓娜; 李代伟; 樊昌元; 张道元; 邓昌建; 唐必秀
Original assignee: Chengdu University of Information Technology
Current assignee: Chengdu University of Information Technology
Priority date: 2019-11-08
Filing date: 2019-11-08
Publication date: 2023-04-11
Anticipated expiration: 2039-11-08
Also published as: CN110696672A

Abstract

The invention discloses a system for realizing rapid charging of a power battery, which mainly solves the problem that the service life of the battery is very short due to the fact that the power battery is charged by adopting a constant-current charging mode and a constant-voltage charging mode in the prior art. The system comprises an EMI filter circuit connected with a mains supply, a rectifying circuit connected with the EMI filter circuit, a BOOST synchronous rectifying circuit and an auxiliary power supply circuit which are simultaneously connected with a rectifying current, a rechargeable battery connected with the BOOST synchronous rectifying circuit, a control circuit which is simultaneously connected with the rechargeable battery and the auxiliary power supply circuit and feeds signals back to the BOOST synchronous rectifying circuit, and a prompt circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit. Through the scheme, the invention achieves the purposes of controlling the main circuit through the control circuit and charging the battery load, and has very high practical value and popularization value.

Description

System for realizing rapid charging of power battery

Technical Field

The invention belongs to the technical field of battery charging, and particularly relates to a system for realizing rapid charging of a power battery.

Background

Whether the electric automobile can be developed quickly or not is an extremely important part for improving the charging mode, and if the charging time is too long and the endurance is poor, the electric automobile can be in a standstill, so that the research on improving the charging mode of the power battery is very important. At first, the charging mode of the power battery is single, the power battery is mainly charged by adopting a constant-current charging mode and a constant-voltage charging mode, the two charging methods are simple, and no place needing to be controlled exists. The battery is charged by the two charging modes, the service life of the battery is very short, and the maximum acceptable charging curve of the battery is found later through the research on the characteristics of the battery. According to the charging curve, the current required by the battery is intuitively known to be smaller and smaller along with the charging of the power battery. Therefore, in the initial stage of constant voltage charging of the power battery, when the large current generated in the charging circuit or the constant current charging is adopted, the large current generated in the final stage of charging exceeds the maximum charging current accepted by the battery, and the battery is in an overcharged state. These causes can cause polarization and gassing of the battery, which shortens battery life, reduces battery capacity, and damages the power battery. On the basis, researchers at home and abroad further optimize the charging mode, and provide various charging modes such as a constant-current constant-voltage charging mode, a positive pulse charging method, a negative pulse charging method, a variable-current intermittent charging method, a variable-voltage charging method and the like, and a multi-stage constant-current charging method and the like which are developed in recent research work. The modes not only greatly improve the charging efficiency and the charging speed of the power battery, but also ensure the service life of the battery and inhibit the reactions of polarization phenomenon, gassing phenomenon and the like of the battery to the damage of the battery. In the process of rapid development of electric vehicles, lithium batteries are the most important part of power batteries, and the research on the charging mode of the lithium batteries is very important. However, to eliminate the polarization phenomenon in the true sense, a more complete fast charging mode is sought, and more research is needed. The electric automobile as a new energy automobile is a necessary process to replace the traditional automobile. In order to have a place for the huge industry in the automotive field, a power battery is taken as the core of an electric automobile. Therefore, it is very important to research the way of fast charging the power battery.

Disclosure of Invention

The invention aims to provide a system for realizing rapid charging of a power battery, which mainly solves the problem that the service life of the battery is very short due to the fact that the power battery is charged by adopting a constant-current charging mode and a constant-voltage charging mode in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a system for realizing rapid charging of a power battery comprises an EMI filter circuit connected with a mains supply, a rectifying circuit connected with the EMI filter circuit, a BOOST synchronous rectifying circuit and an auxiliary power supply circuit which are simultaneously connected with a rectifying current, a rechargeable battery connected with the BOOST synchronous rectifying circuit, a control circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit and feeding back signals to the BOOST synchronous rectifying circuit, and a prompt circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit;

the EMI filter circuit comprises a capacitor C1 with two ends respectively connected with a mains supply, a transformer T1 with an input end respectively connected with two ends of the capacitor C1, a capacitor C2 with two ends respectively connected with an output end of the transformer, a capacitor C3 and a capacitor C4 which are respectively connected with two ends of the capacitor C2 after being connected in series, and a transformer T2 with an input end simultaneously connected with two ends of the capacitor C2, wherein one end of the capacitor C3 is connected with one end of the capacitor C2 to be grounded, and the output end of the transformer T2 is connected with a rectification circuit;

the EMI filter circuit, the rectifying circuit and the BOOST synchronous rectifying circuit connected with the mains supply form a main circuit.

Furthermore, the rectifier circuit is a bridge rectifier circuit, the AC end of the bridge rectifier circuit is connected with the output end of the transformer T2, and the positive and negative ends of the bridge rectifier circuit are respectively connected with the filter capacitor C5 and the BOOST synchronous rectifier circuit, wherein the capacitor C5 is an electrolytic capacitor, and the positive electrode is connected with the positive electrode of the bridge rectifier.

Further, the BOOST synchronous rectification circuit comprises an electrolytic capacitor C6 with the positive electrode and the negative electrode respectively connected with the positive end and the negative end of the bridge rectification circuit, a capacitor C7 respectively connected with the two ends of the electrolytic capacitor C6, an inductor L1 connected with the positive electrode end of the electrolytic capacitor C6 at one end, an MOS tube Q2 with the drain electrode connected with the other end of the inductor L1 and the source electrode connected with the negative electrode of the electrolytic capacitor C6, an MOS tube Q1 with the source electrode connected with the drain electrode of the MOS tube Q2, an electrolytic capacitor C8 with the positive electrode connected with the drain electrode of the MOS tube Q1 and the negative electrode connected with the source electrode of the MOS tube Q2 after parallel connection, and a capacitor C9, wherein the two ends of the capacitor C9 are connected with a rechargeable battery, and the source electrode of the MOS tube Q2 is grounded.

Specifically, the control circuit includes a driving chip IR2111 with a 6 th pin connected to a source of a MOS transistor Q1 in the BOOST synchronous rectification circuit, a resistor R4 with one end connected to the 6 th pin of the driving chip IR2111 and the other end connected to a gate of the MOS transistor Q1, a resistor R1 with one end connected to the 7 th pin of the driving chip IR2111 and the other end connected to the gate of the MOS transistor Q1, a capacitor C10 with one end connected to the 6 th pin of the driving chip IR2111 and the other end connected to a 8 th pin of the driving chip IR2111, a resistor R7 with one end connected to the 4 th pin of the driving chip IR2111 and the other end connected to the gate of the MOS transistor Q2, a resistor R8 with one end connected to the gate of the MOS transistor Q2 and the other end connected to ground, a diode D5 with a positive electrode connected to the 1 st pin of the driving chip IR2111, a negative electrode connected to the 8 th pin of the driving chip IR2111, a capacitor C11 with one end connected to the 1 st pin of the driving chip 2111 and the other end connected to the 3 rd pin of the driving chip IR2111, a collector of the driving chip 2111 connected to the driving chip, a base electrode of the driving chip Q3, and a base electrode of the driving chip Q3 of the driving chip, and a base electrode of the chip, wherein the chip R3 of the chip are connected to the driving chip, and the base of the chip R3 of the single chip, and the base of the chip are connected to the chip, and the single chip 2111, and the triode chip, and the base of the chip Q3 of the chip, and the chip, wherein the chip are connected to the chip 2111.

Compared with the prior art, the invention has the following beneficial effects:

(1) The main function of the main circuit design of the invention is to filter out higher harmonics in the power grid after the commercial power AC220V passes through the EMI rectification circuit, so as to avoid damaging elements in the circuit and even influencing the performance of the rechargeable battery. Then, alternating current is converted into direct current through a rectifying circuit, and the direct current is output to an external rechargeable battery through a BOOST synchronous rectifying circuit, namely the running state of the main circuit. The main circuit is controlled by the control circuit to charge the battery load.

(2) The invention adjusts the output voltage of the charging circuit through the control circuit, and performs constant current charging and constant voltage charging on the battery, thereby completing the constant current and constant voltage rapid charging on a certain basis. The invention has the advantages that the internal resistance of the battery is larger and larger along with the charging, and the voltage drop at two ends of the battery is higher and higher. In order to ensure that the constant current charging is carried out on the battery load, the output voltage of the main circuit is higher and higher, and the charging mode is not changed until the requirement of constant voltage output is met, so that the constant voltage charging mode is carried out.

(3) The rectifier circuit of the invention adopts bridge rectification, and the full-bridge rectification adopts four rectifier diodes in the circuit, thus reducing half of reverse voltage and current borne by the rectifier diodes, increasing the output power of the circuit by two rectifier diodes, and being in line with a high-power circuit for rapidly charging a power battery.

Drawings

FIG. 1 is a block diagram of the system architecture of the present invention.

FIG. 2 is a schematic circuit diagram of an EMI filter circuit according to the present invention.

Fig. 3 is a schematic circuit diagram of a rectifier circuit of the present invention.

FIG. 4 is a schematic circuit diagram of a BOOST synchronous rectification circuit of the present invention.

Fig. 5 is a circuit schematic of the control circuit of the present invention.

FIG. 6 is a schematic diagram of the auxiliary power circuit 12V of the present invention.

FIG. 7 is a schematic diagram of an auxiliary power supply circuit 5V circuit according to the present invention

FIG. 8 is a schematic circuit diagram of the hint circuit of the present invention.

Detailed Description

The present invention is further illustrated by the following figures and examples, which include, but are not limited to, the following examples.

Examples

As shown in fig. 1 to 8, a system for realizing fast charging of a power battery comprises an EMI filter circuit connected with a mains supply, a rectifier circuit connected with the EMI filter circuit, a BOOST synchronous rectifier circuit and an auxiliary power supply circuit simultaneously connected with a rectifier current, a rechargeable battery connected with the BOOST synchronous rectifier circuit, a control circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit and feeding back signals to the BOOST synchronous rectifier circuit, and a prompt circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit; the EMI filter circuit comprises a capacitor C1 with two ends respectively connected with a mains supply, a transformer T1 with an input end respectively connected with two ends of the capacitor C1, a capacitor C2 with two ends respectively connected with an output end of the transformer, a capacitor C3 and a capacitor C4 which are respectively connected with two ends of the capacitor C2 after being connected in series, and a transformer T2 with an input end simultaneously connected with two ends of the capacitor C2, wherein one end of the capacitor C3 is connected with one end of the capacitor C2 to be grounded, and the output end of the transformer T2 is connected with a rectification circuit; the EMI filter circuit, the rectifying circuit and the BOOST synchronous rectifying circuit connected with the mains supply form a main circuit.

As shown in fig. 2, when the EMI filter circuit charges the power battery, a commercial AC220V power supply is input, in order to prevent the interference of the AC signals with other frequencies in the power grid to the power battery and the charging circuit, the high-frequency signals in the external power grid will affect the charging circuit, and even damage the performance of the power battery, the EMI filter circuit is used to input the AC power with the frequency of 50Hz in the power grid to the charging device, filter out other high-frequency signals, and reduce the external electromagnetic interference.

When a controllable circuit is adopted, a signal is needed to control the switching process of the controllable silicon, compared with an uncontrollable circuit, a driving circuit of an MOS (metal oxide semiconductor) tube is added, and the circuit structure is also complicated. Because a BOOST synchronous rectification circuit is added behind the rectification circuit, the switching duty ratio of an MOS tube in the circuit is changed, and the output voltage is adjusted, an uncontrollable rectification circuit is adopted, the cost is saved, a control circuit is reduced, and the circuit structure is simple.

The working principle of the bridge rectifier circuit in fig. 3 is as follows: rectifier diodes D1 and D4 are a set of bridge arms, and D2 and D3 are another set of bridge arms. When the point of Ua is higher than the potential of Ub, the rectifier diodes D3 and D2 are conducted, and current flows back to the end of the power Ub from the power Ua through the D3, the load and the D2; when the voltage of Ub is higher than that of Ua, the rectifier diodes D4 and D1 are conducted, and current flows from the power supply Ub through the D4, the load and the D1 to the power supply a end. After passing through the rectifying circuit, the output voltage is a sine wave with all positive voltages, thereby realizing bridge rectification. And a large filter capacitor C5 is added at the end of the rectifying circuit, so that a relatively stable voltage can be obtained.

FIG. 4 is a BOOST synchronous rectification circuit diagram. The voltage obtained by the rectifying circuit is about 310V, and the initial voltage required by the designed high-power charging mode is about 400V, so that the BOOST chopper circuit is selected to increase the voltage. If the traditional BOOST circuit is adopted, when the Schottky diode reverses, the diode plays a role in isolation, and the service life of the circuit cannot be influenced. When the diode is conducted in the forward direction, because the diode has a voltage drop, much energy is consumed, and the power efficiency is reduced, so that the charging efficiency is higher the lower the voltage drop of the selected diode is. Therefore, the main circuit of the design adopts the BOOST synchronous rectification circuit, utilizes the advantages of low on-state voltage, small on-state resistance and low loss of the MOS tube to replace a Schottky diode in the BOOST booster circuit with the MOS tube, and charges the battery after the input voltage is boosted by the BOOST synchronous rectification circuit. The voltage and current across the cell are then collected. The acquired signals are input into the singlechip after analog-to-digital conversion, and set PID operation is carried out, so that the output voltage of the charging circuit is controlled. Because the knowledge of the single chip microcomputer is limited, the STM32 single chip microcomputer is adopted to analyze current sampling, corresponding PWM waves are output, then the PWM waves are amplified, the MOS tube is controlled, and finally constant-current charging and constant-voltage charging are realized.

Fig. 5 shows a control circuit, when a single chip microcomputer (STM 32 series single chip microcomputer) outputs a PWM signal, the signal can be amplified by a triode and then input to a driving chip, and through the chip, a completely opposite signal can be obtained in addition to a mode-identical PWM signal. Thus, the standard of the full symbol BOOST synchronous rectification circuit just controls the switching of two MOS tubes in the booster circuit, and the IR2111 can be fully used for +600V.

The auxiliary power supply circuit of the invention respectively adopts the existing 12V stabilized power supply circuit and 5V stabilized power supply circuit, the 12V stabilized power supply circuit adopts an LM7812 stabilized voltage chip to reduce the input 15V direct current voltage to 12V stabilized voltage, and because the input power supply voltage of the driving chip IR2111 and the operational amplifier LM358 is 12V, a voltage of 12V is needed. And the maximum current of LM7812 can reach 1.5A, and the normal use of the electronic elements can be completely endured. Meanwhile, filter capacitors are added at the input end and the output end of the LM7812 voltage stabilizing chip, so that the voltage is more stable, an electronic element cannot be damaged, and the auxiliary power supply circuit is the first part of the auxiliary power supply circuit. The second part of the auxiliary power supply adopts an LM7805 voltage stabilizing chip to stabilize the input 12V voltage to 5V, and the maximum current of the auxiliary power supply can also reach 1.5A, so that the auxiliary power supply conforms to the circuit design. Similarly, a filter capacitor is added at the output end of LM 7805. 5V voltage mainly supplies power to ACS712, STM32 singlechip and two LED diodes of current sensor

The indicating circuit is an existing conventional circuit, the common end of the relay JK1 is connected to a 5V stabilized power supply, the normally closed end is grounded through an LED diode emitting red light, and the normally open end is grounded through an LED diode emitting yellow light. The coil one end direct ground connection of relay JK1, the other end is connected at voltage comparator's output, embeds a resistance in the relay, and the effect of this resistance limits the size of electric current, guarantees relay normal operating. When the red LED is on, the constant current charging is performed; when the yellow LED diode is on, it indicates that constant voltage charging is being performed.

The above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, but all changes that can be made by applying the principles of the present invention and performing non-inventive work on the basis of the principles shall fall within the scope of the present invention.

Claims

1. A system for realizing rapid charging of a power battery is characterized by comprising an EMI filter circuit connected with a mains supply, a rectifying circuit connected with the EMI filter circuit, a BOOST synchronous rectifying circuit and an auxiliary power supply circuit which are simultaneously connected with rectifying currents, a rechargeable battery connected with the BOOST synchronous rectifying circuit, a control circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit and feeding signals back to the BOOST synchronous rectifying circuit, and a prompt circuit simultaneously connected with the rechargeable battery and the auxiliary power supply circuit;

the EMI filter circuit, the rectifying circuit and the BOOST synchronous rectifying circuit connected with the mains supply form a main circuit;

the rectifying circuit is a bridge rectifying circuit, the AC end of the bridge rectifying circuit is connected with the output end of the transformer T2, and the positive end and the negative end of the bridge rectifying circuit are respectively connected with a filter capacitor C5 and a BOOST synchronous rectifying circuit, wherein the capacitor C5 is an electrolytic capacitor, and the positive electrode of the capacitor is connected with the positive electrode of the bridge rectifying circuit;

the BOOST synchronous rectification circuit comprises an electrolytic capacitor C6, a capacitor C7, an inductor L1, a MOS tube Q2, a source electrode, an MOS tube Q2, an electrolytic capacitor C8 and a capacitor C9, wherein the positive electrode and the negative electrode of the electrolytic capacitor C6 are respectively connected with the positive end and the negative end of the bridge rectification circuit, the capacitor C7 is respectively connected with the two ends of the electrolytic capacitor C6, the inductor L1 is connected with the positive electrode end of the electrolytic capacitor C6 at one end, the drain electrode is connected with the other end of the inductor L1, the source electrode is connected with the negative electrode of the electrolytic capacitor C6, the MOS tube Q1 is connected with the drain electrode of the MOS tube Q2, the positive electrode is connected with the drain electrode of the MOS tube Q1 after the parallel connection, and the negative electrode is connected with the source electrode of the MOS tube Q2;

the control circuit comprises a drive chip IR2111 with a 6 th pin connected with a source electrode of an MOS tube Q1 in a BOOST synchronous rectification circuit, a resistor R4 with one end connected with the 6 th pin of the drive chip IR2111 and the other end connected with a grid electrode of the MOS tube Q1, a resistor R1 with one end connected with the 7 th pin of the drive chip IR2111 and the other end connected with the grid electrode of the MOS tube Q1, a capacitor C10 with one end connected with the 6 th pin of the drive chip IR2111 and the other end connected with the 8 th pin of the drive chip IR2111, a resistor R7 with one end connected with the 4 th pin of the drive chip IR2111 and the other end connected with the grid electrode of the MOS tube Q2, a resistor R8 with one end connected with the grid electrode of the MOS tube Q2 and the other end grounded, a diode D5 with a positive pole connected with the 1 st pin of the drive chip IR2111, a negative pole connected with the 8 th pin of the drive chip IR2111, a capacitor C11 with the 1 st pin of the drive chip IR2111, a first end connected with the 3 rd pin of the drive chip IR2111, a collector connected with the drive chip IR2111, and a triode, and a collector of the drive chip, wherein the emitter of the drive chip is connected with the drive chip and the drive chip, the emitter of the drive chip and the drive chip, and the emitter of the drive chip is connected with the drive chip Q1, and the emitter of the chip, and the emitter of the chip is connected with the drive chip and the resistor R3, and the emitter of the chip.