CN112491121A - Lithium battery charging circuit and charging method based on BUCK mode - Google Patents
Lithium battery charging circuit and charging method based on BUCK mode Download PDFInfo
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- CN112491121A CN112491121A CN202011281519.3A CN202011281519A CN112491121A CN 112491121 A CN112491121 A CN 112491121A CN 202011281519 A CN202011281519 A CN 202011281519A CN 112491121 A CN112491121 A CN 112491121A
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- 238000007600 charging Methods 0.000 title claims abstract description 116
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 57
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000003990 capacitor Substances 0.000 claims abstract description 31
- 238000001914 filtration Methods 0.000 claims description 17
- 238000010277 constant-current charging Methods 0.000 claims description 12
- 238000010280 constant potential charging Methods 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 abstract description 3
- 239000002253 acid Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000010926 waste battery Substances 0.000 description 2
- 239000013543 active substance Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010892 electric spark Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
- H02J7/04—Regulation of charging current or voltage
- H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
- H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
- H02J7/0049—Detection of fully charged condition
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
- H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J2207/20—Charging or discharging characterised by the power electronics converter
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
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- Electromagnetism (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
The invention relates to a lithium battery charging circuit and a charging method based on a BUCK mode, wherein the charging circuit comprises a preceding stage control circuit and a voltage reduction charging circuit, and the output end of the preceding stage control circuit is connected with the input end of the voltage reduction charging circuit; the front-stage control circuit comprises an EMC filter circuit, a rectifying filter circuit and a BUCK mode PFC circuit; the rectification filter circuit is arranged between the EMC filter circuit and the BUCK mode PFC circuit; the front-stage control circuit is formed by arranging the EMC filter circuit, the rectifier filter circuit and the BUCK mode PFC circuit, so that a subsequent BUCK charging circuit can adopt a filter capacitor with lower withstand voltage, a power switch tube with lower withstand voltage and an inductor with lower inductance, higher conversion efficiency can be obtained, and the whole volume of a power supply is reduced.
Description
Technical Field
The invention relates to the field of BUCK circuits, in particular to a lithium battery charging circuit based on a BUCK mode.
Background
The initial rechargeable batteries were lead acid batteries, conventional lead acid batteries, which made the device more portable, but followed the problem of disposal of large quantities of waste batteries. With the development of the battery field, a lithium battery appears later, and compared with a lead-acid storage battery, the lithium battery has smaller volume and longer service life, so that the cost can be saved, and the problem of waste battery treatment can be relieved to a certain extent, and the lithium battery is rapidly popularized and developed. Because the chemical properties and physical properties of lithium batteries and lead-acid batteries are different, the charging mode of the traditional lead-acid battery is difficult to be applied in the lithium batteries, and on the other hand, because the energy density of the lithium batteries is higher, a stricter charging management scheme is also needed. At present, mature lithium battery charging modes are designed based on a lithium battery charging management chip, but the charging modes are suitable for low lithium battery voltage, generally below 20V, and the charging scheme of high-power lithium batteries of 48V and above is not perfect. Therefore, a charging circuit suitable for a high-power lithium battery is required.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a lithium battery charging circuit based on a BUCK mode, which is simple in structure and convenient to use and can realize the step-by-step charging of high-power lithium batteries.
A lithium battery charging circuit based on a BUCK mode comprises a preceding stage control circuit and a voltage reduction charging circuit, wherein the output end of the preceding stage control circuit is connected with the input end of the voltage reduction charging circuit; the front-stage control circuit comprises an EMC filter circuit, a rectifying filter circuit and a BUCK mode PFC circuit; the rectification filter circuit is arranged between the EMC filter circuit and the BUCK mode PFC circuit.
Further, the EMC filter circuit comprises an EMC filter, the input end of the EMC filter is connected with the power supply voltage, and the output end of the EMC filter is connected with the input end of the rectifying filter circuit; the rectifying and filtering circuit comprises a rectifying bridge and a filtering capacitor E1; the rectifier bridge is a full-bridge rectifier circuit and comprises diodes D1, D2, D3 and D4; and a filter capacitor E1 is connected between the positive electrode and the negative electrode of the output end of the rectifier bridge, and a filter capacitor E1 is positioned between the rectifier bridge and the BUCK mode PFC circuit.
Further, the BUCK mode PFC circuit comprises a PFC control chip, a resistor R1, a resistor R2, a switching tube Q1, a diode D5, an inductor L1 and a capacitor E2; the negative electrode of the diode D5 is connected with the positive electrode of the output end of the rectifying and filtering circuit, the negative electrode of the diode D5 is connected with the drain electrode of the switching tube Q1, the source electrode of the switching tube Q1 is connected with the resistor R2, the other end of the resistor R2 is connected with the negative electrode of the output end of the rectifying and filtering circuit, and the switching tube Q1 is an N-channel mos tube; the grid electrode of the switching tube Q1 is connected with the output end of the PFC control chip, and a pull-down resistor R1 is arranged between the PFC control chip and the grid electrode of the switching tube Q1; one end of an inductor L1 is connected between the anode of the diode D5 and the drain of the switching tube Q1, the other end of the inductor L1 is connected with one end of a capacitor E2, and the other end of the capacitor E2 is connected with the cathode of a diode D5; both ends of the capacitor E2 are output in the BUCK mode PFC circuit.
Further, the buck charging circuit comprises a single chip microcomputer, a resistor R3, a resistor R4, a switching tube Q2, a diode D6 and an inductor L2; the cathode of the diode D6 is connected with the anode of the output end of the BUCK mode PFC circuit, the cathode of the diode D6 is connected with the drain of the switching tube Q2, the source of the switching tube Q2 is connected with the resistor R4, and the other end of the resistor R4 is connected with the cathode of the output end of the BUCK mode PFC circuit; the switching tube Q2 is an mos tube with an N channel; the grid of the switching tube Q2 is connected with the output end of the single chip microcomputer, and a pull-down resistor R3 is arranged between the single chip microcomputer and the grid of the switching tube Q2; one end of an inductor L2 is connected between the anode of the diode and the drain of the switching tube Q2, and the other end of the inductor L2 and the cathode of the diode D6 are used as the output of the buck charging circuit.
A charging method of a lithium battery charging circuit based on a BUCK mode comprises the following steps:
the method comprises the following steps: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than the full-charge voltage of the battery; if the battery voltage is lower than the full-electricity voltage of the battery, entering a second step; otherwise, entering a sleep mode, and returning to the first step after the interval time t1 in the sleep mode; the lithium battery is a battery string consisting of N single batteries; the voltage range of a single battery is 2.75V-4.2V, and the full-electricity voltage of the battery is 4.2 NV;
step two: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than a preset pre-charging voltage threshold value or not; the pre-charge voltage threshold is 3 NV; if the battery voltage is lower than the pre-charging voltage threshold value, trickle charging is carried out through a charging circuit until the battery voltage reaches the pre-charging voltage threshold value, and the step three is carried out, wherein the charging current value of the trickle charging is 0.01C; c is the representation mode of the nominal capacity of the battery to the current; if the battery voltage is higher than or equal to the pre-charging voltage threshold value, entering a step three;
step three: the lithium battery is subjected to constant current charging through a charging circuit, and the charging current value of the constant current charging is 0.2-1C; until the battery voltage reaches the full-charge voltage of the battery;
step four: after the single chip microcomputer judges that the battery is charged to full voltage, the battery is converted into constant voltage charging, the charging current is gradually reduced at the moment, and the charging is finished until the charging current is reduced to 0.01C;
step five: the singlechip interval set time t2 judges whether the battery voltage is lower than a recharging voltage threshold value; if the battery voltage is lower than the set recharging voltage threshold value, returning to the step two; and if the battery voltage is not lower than the recharging voltage threshold value, returning to the step five.
Further, in the first step, the interval time t1 is 0, and the singlechip monitors the battery voltage in real time in the sleep mode and judges whether the battery voltage is lower than the full-charge voltage of the battery.
Further, in the fifth step, the time t2 is set to be 0, and the single chip microcomputer judges whether the battery voltage is lower than the recharging voltage threshold value in real time.
Furthermore, the charging circuit comprises a preceding stage control circuit and a voltage reduction charging circuit; the switching frequency of the switching tube Q1 in the preceding stage control circuit is set to 100kHz, and the range of the switching duty ratio D of the switching tube Q1 is related to the input voltage Uin and the output voltage Uout of the BUCK mode PFC circuit and is shown as
Where Dmax represents the maximum duty cycle and Dmin represents the minimum duty cycle; uinmin represents a minimum input voltage in the BUCK mode PFC circuit, Uinmax represents a maximum input voltage in the BUCK mode PFC circuit; uout represents the output voltage of the BUCK mode PFC circuit.
Further, the buck charging circuit comprises a switching tube Q2, and the switching frequency of the switching tube Q2 is set to be 100 kHz.
Further, in the second step, the duty ratio of the switching tube Q2 is controlled by the output PWM wave of the singlechip to be less than 10%, so that trickle charging is realized; in the third step, the single chip microcomputer outputs PWM waves to control the duty ratio range of the switching tube Q2 to be 40% -60%, and constant-current charging is realized; in the fourth step, the singlechip outputs PWM waves to control the duty ratio of the switching tube Q2 to gradually decrease until the charging is finished, and the constant-voltage charging is realized.
The invention has the beneficial effects that:
the EMC filter circuit, the rectifier filter circuit and the BUCK mode PFC circuit form a preceding stage control circuit, so that a subsequent BUCK charging circuit can adopt a filter capacitor with lower withstand voltage, a power switch tube with lower withstand voltage and an inductor with lower inductance, higher conversion efficiency can be obtained, and the whole volume of a power supply is reduced;
by setting the switching frequency of the switching tubes Q1 and Q2 to be 100kHz, the range of electromagnetic interference (EMI) generated by switching the switching tubes Q1 and Q2 is higher than 100kHz, and interference on charging of the lithium battery is avoided;
through setting up trickle charge, constant current charge and constant voltage charge's the mode of charging step by step, better protection lithium cell when guaranteeing to accomplish quick realization and charge prolongs the life of lithium cell.
Drawings
FIG. 1 is a block diagram of a first embodiment of the present invention;
FIG. 2 is a preceding stage control circuit topology according to a first embodiment of the present invention;
fig. 3 is a step-down charging circuit topology according to a first embodiment of the invention;
fig. 4 is a flowchart of a charging method according to a first embodiment of the invention;
fig. 5 is a schematic diagram of a charging curve of a lithium battery according to a first embodiment of the invention;
fig. 6 is a diagram of a current voltage waveform of the BUCK mode PFC circuit when the switching transistor Q1 operates according to the first embodiment of the present invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
The first embodiment is as follows:
as shown in fig. 1, a lithium battery charging circuit based on BUCK mode includes a front stage control circuit and a BUCK charging circuit. The output end of the preceding stage control circuit is connected with the input end of the voltage reduction charging circuit.
The front stage control circuit comprises an EMC filter circuit, a rectifying filter circuit and a BUCK mode PFC circuit. The rectification filter circuit is arranged between the EMC filter circuit and the BUCK mode PFC circuit; the EMC circuit is used for inhibiting and eliminating strong electromagnetic interference and electric spark interference on the site of the industrial automation system; the rectification filter circuit is used for converting the alternating current passing through the EMC filter circuit into direct current and filtering to smooth the waveform of the direct current voltage; the BUCK mode PFC circuit is used for carrying out voltage reduction processing on the output voltage of the rectifying and filtering circuit, correcting power factors and improving the power factors of the circuit.
As shown in fig. 2, the EMC filter circuit comprises an EMC filter, the input of which is connected to the mains voltage, in this case 110 VAC-230 VAC, and the output of which is connected to the input of the rectifying filter circuit. The rectifying and filtering circuit comprises a rectifying bridge and a filtering capacitor E1, wherein the rectifying bridge is a conventional full-bridge circuit and comprises diodes D1, D2, D3 and D4. And a filter capacitor E1 is connected between the positive electrode and the negative electrode of the output end of the rectifier bridge, and a filter capacitor E1 is positioned between the rectifier bridge and the BUCK mode PFC circuit. The BUCK mode PFC circuit comprises a PFC control chip, a resistor R1, a resistor R2, a switching tube Q1, a diode D5, an inductor L1 and a capacitor E2. The negative electrode of the diode D5 is connected with the positive electrode of the output end of the rectifying and filtering circuit, the negative electrode of the diode D5 is connected with the drain electrode of the switching tube Q1, the source electrode of the switching tube Q1 is connected with the resistor R2, and the other end of the resistor R2 is connected with the negative electrode of the output end of the rectifying and filtering circuit, wherein the switching tube Q1 is an N-channel mos tube, and a P-channel mos tube can be adopted in some other embodiments. The gate of the switching tube Q1 is connected to the output end of the PFC control chip, a resistor R1 is provided between the PFC control chip and the gate of the switching tube Q1, and the resistor R1 is used as a pull-down resistor. One end of an inductor L1 is connected between the anode of the diode D5 and the drain of the switching tube Q1, the other end of the inductor L1 is connected with one end of a capacitor E2, and the other end of the capacitor E2 is connected with the cathode of a diode D5. Both ends of the capacitor E2 are used as outputs in the BUCK mode PFC circuit.
As shown in fig. 3, the buck charging circuit includes a single chip, a resistor R3, a resistor R4, a switching tube Q2, a diode D6, and an inductor L2. The cathode of the diode D6 is connected to the anode of the output terminal of the BUCK mode PFC circuit, the cathode of the diode D6 is connected to the drain of the switching tube Q2, the source of the switching tube Q2 is connected to the resistor R4, and the other end of the resistor R4 is connected to the cathode of the output terminal of the BUCK mode PFC circuit, wherein the switching tube Q2 is an N-channel mos tube, and in some other embodiments, a P-channel mos tube may also be used. The grid of the switch tube Q2 is connected with the output end of the single chip microcomputer, a resistor R3 is arranged between the single chip microcomputer and the grid of the switch tube Q2, and the resistor R3 is used as a pull-down resistor. One end of an inductor L2 is connected between the anode of the diode and the drain of the switching tube Q2, and the other end of the inductor L2 and the cathode of the diode D6 are used as the output of the buck charging circuit.
In the implementation process, the alternating current of 110V-230V is adjusted to the direct current of 100V or below through the pre-stage control circuit, so that the voltage-reducing charging circuit can adopt a filter capacitor with lower withstand voltage, a power switch tube with lower withstand voltage and an inductor with lower inductance, can obtain higher conversion efficiency, and is higher in level on the whole volume of the power supply.
In the step-down charging circuit, if the switching tube Q2 is switched on, the current returns to the V-end from V + through the lithium battery BAT, the inductor L2, the switching tube Q2 and finally the sampling resistor R4; if the switching tube Q2 is turned off, the electromotive force stored in the inductor L2 may cause the current to flow through the fast recovery diode D6 to the positive electrode of the lithium battery BAT, thereby completing the charging of the lithium battery; the charging current is adjusted by adjusting the duty ratio of the switching tube Q2.
As shown in fig. 4 and 5, a method for charging a lithium battery based on a BUCK mode includes the following steps:
the method comprises the following steps: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than the full-charge voltage of the battery; if the battery voltage is lower than the full-electricity voltage of the battery, entering a second step; otherwise, entering a sleep mode, and returning to the first step after the interval time t1 in the sleep mode; the lithium battery is a battery string consisting of N single batteries; the voltage range of the single battery is 2.75V-4.2V; the full-battery voltage represents the battery voltage when the electric quantity of the lithium battery is 100%, and is 4.2 NV;
step two: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than a preset pre-charging voltage threshold value or not; the precharge voltage threshold is 3NV in this embodiment; if the battery voltage is lower than the pre-charging voltage threshold value, trickle charging is carried out through a charging circuit until the battery voltage reaches the pre-charging voltage threshold value, and the step three is carried out, wherein the charging current value of the trickle charging is 0.01C; c is a representation of the nominal capacity of the battery versus current, e.g., the battery has a capacity of 20Ah, 1C is the charging current 20A; if the battery voltage is higher than or equal to the pre-charging voltage threshold value, entering a step three;
step three: the lithium battery is subjected to constant current charging through a charging circuit, and the charging current value of the constant current charging is 0.2-0.3C; until the battery voltage reaches the full-charge voltage of the battery;
step four: after the single chip microcomputer judges that the battery is charged to full voltage, the battery is converted into constant voltage charging, the charging current is gradually reduced at the moment, and the charging is finished until the charging current is reduced to 0.01C;
step five: the singlechip interval set time t2 judges whether the battery voltage is lower than a recharging voltage threshold value; if the battery voltage is lower than the set recharging voltage threshold value, returning to the step two; if the battery voltage is not lower than the recharging voltage threshold value, returning to the step five; the recharge voltage threshold is 3.89 NV.
The battery voltage is detected through voltage detection equipment, and a detection result is transmitted to the single chip microcomputer.
The relationship between the battery power and the battery voltage of the single battery in the first step is shown in a first table:
first meter, relation meter of battery electric quantity and battery voltage
| Residual capacity of battery | 0％ | 5％ | 25％ | 50％ | 75％ | 100％ |
| Voltage of battery | 2.75V | 3.50V | 3.73V | 3.85V | 3.95V | 4.20V |
When the battery voltage of the lithium battery is 3NV, the battery voltage of a single battery is 3V at the moment, and the electric quantity of the battery is 0-5%; when the battery voltage of the lithium battery is 4.2NV, the battery voltage of a single battery is 4.2V, and the battery electric quantity is 100%; when the battery voltage of the lithium battery is 3.89NV, the battery voltage of a single battery is 3.89V, and the electric quantity of the battery is 50% -75%.
It should be noted that the interval time t1 may be 0 in step one, and if the interval time t1 is 0, it indicates that the single chip microcomputer monitors the battery voltage in real time in the sleep mode and determines whether the battery voltage is lower than the full-battery voltage. In the fifth step, the set time t2 may be 0, and if the set time t2 is 0, it indicates that the single chip microcomputer determines whether the battery voltage is lower than the recharging voltage threshold in real time.
As shown in fig. 6, the charging circuit in the second step includes a pre-stage control circuit and a step-down charging circuit, wherein the switching frequency of the switching tube Q1 in the pre-stage control circuit is set to 100kHz, so that the range of the electromagnetic interference EMI generated by the switching of the switching tube Q1 is higher than 100 kHz. Wherein the switching duty cycle D of the switching tube Q1 is controlled by the PFC control chip. The range of the switching duty cycle D of the switching tube Q1 is related to the input voltage Uin and the output voltage Uout of the BUCK mode PFC circuit, and is denoted as
Wherein DmaxDenotes the maximum duty cycle, DminRepresents a minimum duty cycle; u shapeinminIndicating the minimum input voltage, U, in a BUCK mode PFC circuitinmaxRepresents the maximum input voltage in the BUCK mode PFC circuit; u shapeoutThe output voltage of the BUCK mode PFC circuit is shown to be 100VDC in this example. The input voltage of the rectifying and filtering circuit is 110 VAC-230 VAC, and the output voltage is 155 VDC-310 VDC after passing through the full-bridge rectifying and filtering circuit, so that U is the voltage of the transformer in the present exampleinminIs 155VDC, UinmaxAt 310VDC, a switching duty cycle range of Q1 of 32.25% -64.5% was obtained. The output voltage of the BUCK mode PFC circuit is stabilized to be 100VDC by adjusting the switching duty ratio of the Q1 through the PFC control chip.
In the rectifying and filtering circuit, the power supply voltage is rectified by an EMC filter through a D1 full bridge, a D2 full bridge, a D3 full bridge and a D4 full bridge, and then electric energy is stored on a capacitor E1. In the BUCK mode PFC circuit, when Uin is larger than Uout, current flows from the positive electrode of the capacitor E1 through the capacitor E2, passes through the inductor L1, passes through the power switch tube Q1, the sampling resistor R2 and returns to the negative electrode of the capacitor E1; when Uin is less than Uout, the current starts from the positive electrode of the capacitor E2, charges the positive electrode of the capacitor E1, and then returns to the negative electrode of the capacitor E2 from the negative electrode of E1 through the sampling resistor R2, the freewheeling diode of the switching tube Q1 and the inductor L1; when Uin is equal to Uout, the switching signal of the PFC control chip is meaningless, and meanwhile, since the input voltage Vin of the preceding stage control circuit is less than Uin, the rectifier bridge composed of D1, D2, D3 and D4 is in an off state. Wherein the output voltage Vout of the preceding stage control circuit is equal to Uout. It should be noted that in this example, since the BUCK mode PFC circuit is a voltage reduction circuit, Uin is always larger than Uout.
In the second step, the singlechip outputs PWM waves to control the duty ratio of the switching tube Q2 to be less than 10%, so that trickle charging is realized; in the third step, the singlechip outputs PWM waves to control the duty ratio range of the switching tube Q2 to be 40% -60%, and constant-current charging is realized; in the fourth step, the duty ratio of the switching tube Q2 is controlled to gradually decrease by the single chip microcomputer outputting PWM waves until the charging is finished, and the duty ratio is 0 at the moment, so that the constant-voltage charging is realized. The frequency range of the switching tube Q2 is related to the model of the selected singlechip and switching tube; the switching frequency of the switching tube Q2 is set to 100kHz in this example in order to avoid electromagnetic interference.
In the battery string formed by 13 single batteries of the lithium battery in the first step in the embodiment, N is 13, so that the pre-charging voltage threshold value is 39V; the full-electricity voltage of the battery is 54.6V in the same way; the recharging voltage threshold is set to be 50.6V, the voltage of a single battery is 3.89V, and the electric quantity of the single battery is between 50% and 75% and is 60%.
In the implementation process, trickle charging is carried out if the battery voltage of the lithium battery is lower than 39V; if the battery voltage of the lithium battery is higher than or equal to 39V and lower than 54.6V, performing constant-current charging, and after the constant-current charging is completed, performing constant-voltage charging to gradually reduce the charging current until the charging is stopped; and if the battery voltage is detected to be lower than 50.6V again, charging is carried out, and judgment is carried out according to the rule. Trickle charging is carried out firstly when the battery is low in electricity quantity, so that active substances in the lithium battery are activated, constant-current charging is carried out after the lithium battery reaches certain electricity quantity, quick charging is realized, and the charging of the lithium battery can be completed under the condition of ensuring the safety of the lithium battery.
The battery charge level can also be detected in some other embodiments to classify trickle charge, constant current charge, and recharge criteria.
The above description is only one specific example of the present invention and should not be construed as limiting the invention in any way. It will be apparent to persons skilled in the relevant art(s) that, having the benefit of this disclosure and its principles, various modifications and changes in form and detail can be made without departing from the principles and structures of the invention, which are, however, encompassed by the appended claims.
Claims (10)
1. A lithium battery charging circuit based on a BUCK mode is characterized by comprising a preceding stage control circuit and a voltage reduction charging circuit, wherein the output end of the preceding stage control circuit is connected with the input end of the voltage reduction charging circuit; the front-stage control circuit comprises an EMC filter circuit, a rectifying filter circuit and a BUCK mode PFC circuit; the rectification filter circuit is arranged between the EMC filter circuit and the BUCK mode PFC circuit.
2. The BUCK mode-based lithium battery charging circuit as recited in claim 1, wherein the EMC filter circuit comprises an EMC filter, an input terminal of the EMC filter is connected to the supply voltage, and an output terminal of the EMC filter is connected to an input terminal of the rectifying filter circuit; the rectifying and filtering circuit comprises a rectifying bridge and a filtering capacitor E1; the rectifier bridge is a full-bridge rectifier circuit and comprises diodes D1, D2, D3 and D4; and a filter capacitor E1 is connected between the positive electrode and the negative electrode of the output end of the rectifier bridge, and a filter capacitor E1 is positioned between the rectifier bridge and the BUCK mode PFC circuit.
3. The BUCK mode-based lithium battery charging circuit as claimed in claim 2, wherein the BUCK mode PFC circuit comprises a PFC control chip, a resistor R1, a resistor R2, a switching tube Q1, a diode D5, an inductor L1 and a capacitor E2; the negative electrode of the diode D5 is connected with the positive electrode of the output end of the rectifying and filtering circuit, the negative electrode of the diode D5 is connected with the drain electrode of the switching tube Q1, the source electrode of the switching tube Q1 is connected with the resistor R2, the other end of the resistor R2 is connected with the negative electrode of the output end of the rectifying and filtering circuit, and the switching tube Q1 is an N-channel mos tube; the grid electrode of the switching tube Q1 is connected with the output end of the PFC control chip, and a pull-down resistor R1 is arranged between the PFC control chip and the grid electrode of the switching tube Q1; one end of an inductor L1 is connected between the anode of the diode D5 and the drain of the switching tube Q1, the other end of the inductor L1 is connected with one end of a capacitor E2, and the other end of the capacitor E2 is connected with the cathode of a diode D5; both ends of the capacitor E2 are output in the BUCK mode PFC circuit.
4. The BUCK mode-based lithium battery charging circuit as claimed in claim 1, wherein the BUCK charging circuit comprises a single chip microcomputer, a resistor R3, a resistor R4, a switching tube Q2, a diode D6 and an inductor L2; the cathode of the diode D6 is connected with the anode of the output end of the BUCK mode PFC circuit, the cathode of the diode D6 is connected with the drain of the switching tube Q2, the source of the switching tube Q2 is connected with the resistor R4, and the other end of the resistor R4 is connected with the cathode of the output end of the BUCK mode PFC circuit; the switching tube Q2 is an mos tube with an N channel; the grid of the switching tube Q2 is connected with the output end of the single chip microcomputer, and a pull-down resistor R3 is arranged between the single chip microcomputer and the grid of the switching tube Q2; one end of an inductor L2 is connected between the anode of the diode and the drain of the switching tube Q2, and the other end of the inductor L2 and the cathode of the diode D6 are used as the output of the buck charging circuit.
5. A charging method of a lithium battery charging circuit based on a BUCK mode is characterized by comprising the following steps:
the method comprises the following steps: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than the full-charge voltage of the battery; if the battery voltage is lower than the full-electricity voltage of the battery, entering a second step; otherwise, entering a sleep mode, and returning to the first step after the interval time t1 in the sleep mode; the lithium battery is a battery string consisting of N single batteries; the voltage range of a single battery is 2.75V-4.2V, and the full-electricity voltage of the battery is 4.2 NV;
step two: the single chip microcomputer judges whether the battery voltage of the lithium battery is lower than a preset pre-charging voltage threshold value or not; the pre-charge voltage threshold is 3 NV; if the battery voltage is lower than the pre-charging voltage threshold value, trickle charging is carried out through a charging circuit until the battery voltage reaches the pre-charging voltage threshold value, and the step three is carried out, wherein the charging current value of the trickle charging is 0.01C; c is the representation mode of the nominal capacity of the battery to the current; if the battery voltage is higher than or equal to the pre-charging voltage threshold value, entering a step three;
step three: the lithium battery is subjected to constant current charging through a charging circuit, and the charging current value of the constant current charging is 0.2-1C; until the battery voltage reaches the full-charge voltage of the battery;
step four: after the single chip microcomputer judges that the battery is charged to full voltage, the battery is converted into constant voltage charging, the charging current is gradually reduced at the moment, and the charging is finished until the charging current is reduced to 0.01C;
step five: the singlechip interval set time t2 judges whether the battery voltage is lower than a recharging voltage threshold value; if the battery voltage is lower than the set recharging voltage threshold value, returning to the step two; and if the battery voltage is not lower than the recharging voltage threshold value, returning to the step five.
6. The method as claimed in claim 5, wherein the time interval t1 is 0, and the single chip microcomputer monitors the battery voltage in real time and determines whether the battery voltage is lower than the full-charge voltage.
7. The method as claimed in claim 5, wherein the time t2 is set to 0 in the fifth step, and the single chip determines whether the battery voltage is lower than the recharging voltage threshold in real time.
8. The charging method of the BUCK mode-based lithium battery charging circuit as claimed in claim 5, wherein the charging circuit comprises a preceding stage control circuit and a BUCK charging circuit; the switching frequency of the switching tube Q1 in the preceding stage control circuit is set to 100kHz, and the range of the switching duty ratio D of the switching tube Q1 is related to the input voltage Uin and the output voltage Uout of the BUCK mode PFC circuit and is shown as
Wherein DmaxDenotes the maximum duty cycle, DminRepresents a minimum duty cycle; u shapeinminIndicating the minimum input voltage, U, in a BUCK mode PFC circuitinmaxRepresents the maximum input voltage in the BUCK mode PFC circuit; u shapeoutRepresents the output voltage of the BUCK mode PFC circuit.
9. The method as claimed in claim 8, wherein the BUCK charging circuit comprises a switch Q2, and the switching frequency of the switch Q2 is set to 100 kHz.
10. The method as claimed in claim 9, wherein in the second step, the singlechip outputs a PWM wave to control the duty ratio of the switching transistor Q2 to be less than 10%, so as to realize trickle charge; in the third step, the single chip microcomputer outputs PWM waves to control the duty ratio range of the switching tube Q2 to be 40% -60%, and constant-current charging is realized; in the fourth step, the singlechip outputs PWM waves to control the duty ratio of the switching tube Q2 to gradually decrease until the charging is finished, and the constant-voltage charging is realized.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101834539A (en) * | 2010-05-27 | 2010-09-15 | 浙江大学 | High-efficiency AC/DC combined converter with wide output voltage range |
| CN102111008A (en) * | 2009-12-29 | 2011-06-29 | 台达电子工业股份有限公司 | High-voltage battery charging system architecture of electric automobile |
| CN103051039A (en) * | 2011-10-11 | 2013-04-17 | 台达电子工业股份有限公司 | High-voltage battery charge system and charger therefor |
| CN203942325U (en) * | 2014-07-20 | 2014-11-12 | 湖南科技学院 | A kind of high performance lithium ion battery charger |
| CN105207328A (en) * | 2015-10-22 | 2015-12-30 | 江苏绿扬电子仪器集团有限公司 | Multifunctional charging module |
-
2020
- 2020-11-16 CN CN202011281519.3A patent/CN112491121A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102111008A (en) * | 2009-12-29 | 2011-06-29 | 台达电子工业股份有限公司 | High-voltage battery charging system architecture of electric automobile |
| CN101834539A (en) * | 2010-05-27 | 2010-09-15 | 浙江大学 | High-efficiency AC/DC combined converter with wide output voltage range |
| CN103051039A (en) * | 2011-10-11 | 2013-04-17 | 台达电子工业股份有限公司 | High-voltage battery charge system and charger therefor |
| CN203942325U (en) * | 2014-07-20 | 2014-11-12 | 湖南科技学院 | A kind of high performance lithium ion battery charger |
| CN105207328A (en) * | 2015-10-22 | 2015-12-30 | 江苏绿扬电子仪器集团有限公司 | Multifunctional charging module |
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