A kind of euqalizing current control circuit, battery circuit and control method
Technical field
The present invention relates to battery charging and discharging technical field, more particularly to a kind of euqalizing current control circuit, battery circuit
And control method.
Background technology
With the extensive application of portable charging apparatus, to the capacity requirement more and more higher of battery, it is desirable to battery output
Electric current is increasing, but electric current output it is too big, not only system design difficulty is substantially improved, at the same under high current battery heating
As outstanding problem.Under conditions of power output is certain, the voltage of battery series connection is higher, and output current will be smaller, and this just makes
The series connection application for obtaining battery is more and more wider.While battery series connection is used widely, problems are also faced with, wherein, such as
What realizes that battery voltage balanced is exactly one of them.
Battery voltage balanced refers to battery during charge or discharge, to keep the voltage of all series-connected cells identical,
But this is very difficult to be realized by battery itself.Although internal resistance and capacity of the series-connected cell when dispatching from the factory per batteries are
Identical, if now being charged with 2A electric currents to two section series-connected cells, the blanking voltage of charging is 8.4V, after charging terminates,
Voltage per batteries is 4.2V;But when battery is after tens of or even hundreds of secondary charge and discharge cycles, even aging, often economize on electricity
Certain random change can all occur in the internal resistance in pond and capacity, if now also being carried out with same equipment to the two sections series-connected cell
8.4V charges, then the voltage per batteries is just no longer 4.2V, but is inversely proportional with battery capacity, is also inversely proportional with internal resistance;Such as
Two section series-connected cells are after discharge and recharge after a while, the capacity attenuation 5% of a batteries, the capacity attenuation of another batteries
20%, when now carrying out 8.4V chargings to the two sections series-connected cell, the voltage of two batteries is approximately:
Battery capacity decay 20% battery both end voltage be:VBAT1=8.4V*0.95/ (0.8+0.95)=4.56V
Battery capacity decay 5% battery both end voltage be:VBAT2=8.4V*0.8/ (0.8+0.95)=3.84V
It was found from above formula, after random decay occurs for battery capacity, it would be possible to cause charging voltage in two batteries
Upper to produce different voltages, the more batteries of capacity attenuation, itself capacity becomes smaller, and both end voltage is higher, or even has been higher by electricity
The safe voltage scope of pond in itself, causes the generation of potential safety hazard.
Because the randomness of battery capacity decay can not change, i.e., series circuit is bound to the decay of battery capacity
There is the problem of cell voltage distribution is uneven, it is therefore desirable in serial connection charge, equilibrium is carried out to the voltage of each rechargeable battery, by force
System makes every section series-connected cell voltage in discharge and recharge all identical, when avoiding certain batteries from causing discharge and recharge because of battery capacity change
Its voltage is different from other cell voltages.
And in existing voltage balance circuit, mainly each cell voltage is compared using comparator, finds out battery
The high battery of voltage, and in serial connection charge, in the battery both ends of a high voltage resistance in parallel, allow part charging current to exist
Flowed away during charging from resistance bypass, reduce the electric current for being filled with the battery, so as to control voltage of the battery in charging to rise
Speed is slower than other batteries, until the cell voltage is identical with other cell voltages, completes equilibrium during battery charging.Existing electricity
Although pressing equalizing circuit is simple easily to realize, there is also shortcomings:Resistance by-pass current is such as used, resistance heating can be caused;Adopt
Although can reduce heating with power resistor, power resistor space-consuming is big, does not utilize and reduces circuit volume;And resistance bypasses
The ability of equalization it is limited, generally within 200mA.Therefore it provides a kind of more efficient equalizing circuit is that present assistant officer is to be solved
Problem.
The content of the invention
In view of the above the shortcomings that prior art, it is an object of the invention to provide a kind of euqalizing current control circuit,
Battery circuit and control method are serious and balanced in the presence of heating is caused because electric current is excessive for solving existing voltage balance circuit
The problem of limited in one's ability.
In order to achieve the above objects and other related objects, the present invention provides a kind of euqalizing current control circuit, the equilibrium
Current control circuit includes:
Voltage detection unit, for sample the first battery first voltage and the second battery second voltage, and pass through by
The first voltage obtains the pressure difference of the first voltage and the second voltage and defeated compared with the second voltage
Go out;
Switching frequency regulates and controls unit, is connected with the voltage detection unit, for being exported according to the voltage detection unit
Pressure difference, compared with setting pressure difference, and according to the pressure difference compared to it is described setting pressure difference deviation multiple,
Retroregulation configuration switch frequency, so as to produce a regulating switch frequency and export;And
Switch element, it is connected with switching frequency regulation and control unit, for regulating and controlling unit output according to the switching frequency
Regulating switch frequency, control the disconnection switched in the switch element and closure, controlled while realizing balancing battery voltage
The average current of the euqalizing current control circuit.
Preferably, the voltage detection unit includes an error amplifier, the first input end of the error amplifier with
The positive pole connection of first battery, the second input of the error amplifier are connected with the positive pole of second battery, institute
The output end for stating error amplifier is connected with the input of switching frequency regulation and control unit.
Preferably, the switching frequency regulation and control unit includes a voltage controlled frequency generator, the voltage controlled frequency generator
Input is connected with the output end of the voltage detection unit, output end and the switch element of the voltage controlled frequency generator
Connection.
Preferably, the switching frequency regulation and control unit is realized using microprocessor.
Preferably, the switch element includes switching capacity, first switch and second switch, one end of the switching capacity
It is connected with the control terminal of the first switch, the other end of the switching capacity is connected with the control terminal of the second switch, institute
The first connection end for stating first switch is connected with the positive pole of first battery, the second connection end of the first switch with it is described
The negative pole connection of first battery, the first connection end of the second switch are connected with the positive pole of second battery, and described second
The second connection end of switch is connected with the negative pole of second battery, wherein, the control terminal of the first switch and described second
The regulating switch FREQUENCY CONTROL that the control terminal of switch exports by switching frequency regulation and control unit.
The present invention also provides a kind of euqalizing current control method, and the control method includes:
Sample the first voltage of the first battery and the second voltage of the second battery, and by by the first voltage with it is described
Second voltage is compared, and obtains the pressure difference of the first voltage and the second voltage;
By the way that the pressure difference is pressed compared with setting pressure difference, and according to the pressure difference compared to the setting
The deviation multiple of difference, retroregulation configuration switch frequency, produce a regulating switch frequency;And
According to the disconnection and closure switched in the regulating switch FREQUENCY CONTROL euqalizing current control circuit, balanced electricity is realized
The average current of the euqalizing current control circuit is controlled while cell voltage.
Preferably, obtaining the method for the regulating switch frequency includes:According to the deviation multiple, described in inverse proportion regulation and control
Configuration switch frequency;The regulating switch frequency meets equation below:Wherein, FreqFor regulating switch frequency,
FreqsFor configuration switch frequency, n is deviation multiple.
Preferably, the average current of the euqalizing current control circuit is a steady state value, and its value meets that formula is as follows:I=C
×ΔVS×Freqs, wherein, I be the euqalizing current control circuit average current, C be switching capacity capacitance, Δ VSTo set
Differential pressure value, FreqsFor configuration switch frequency.
The present invention also provides a kind of battery circuit, and the battery circuit includes:
N batteries;
The charhing unit or energy-storage units being connected with the N sections battery;And
It is connected to two adjacent sections battery both ends, (N-1) as described above described in any one individual euqalizing current control circuit;
Wherein, N is the integer more than or equal to 2.
Preferably, it is cascaded structure or parallel-connection structure that N, which saves the battery,.
As described above, a kind of euqalizing current control circuit, battery circuit and the control method of the present invention, have beneficial below
Effect:
1st, euqalizing current control circuit of the present invention not only solves the equalization problem of cell voltage, improves the control
The ability of equalization of circuit processed, also by regulating and controlling the size of current in the control circuit, improve the safety of the control circuit
Property, avoid and generated heat because electric current is excessive, and then cause the generation of safety problem.
2nd, not only circuit structure is simple for euqalizing current control circuit of the present invention, it is easy to accomplish, and occupy little space,
It is easy to reduce circuit volume.
Brief description of the drawings
Fig. 1 is shown as the circuit block diagram of euqalizing current control circuit of the present invention.
Fig. 2 is shown as the circuit diagram of euqalizing current control circuit described in embodiment one.
Fig. 3 is shown as the flow chart of euqalizing current control method described in embodiment two.
Fig. 4 is shown as the circuit diagram of battery circuit described in embodiment three.
Component label instructions
10 voltage detection units
20 switching frequencies regulate and control unit
30 switch elements
Embodiment
Illustrate embodiments of the present invention below by way of specific instantiation, those skilled in the art can be by this specification
Disclosed content understands other advantages and effect of the present invention easily.The present invention can also pass through specific realities different in addition
The mode of applying is embodied or practiced, the various details in this specification can also be based on different viewpoints with application, without departing from
Various modifications or alterations are carried out under the spirit of the present invention.
Fig. 1 is referred to Fig. 4.It should be noted that the diagram provided in the present embodiment only illustrates this in a schematic way
The basic conception of invention, the component relevant with the present invention is only shown in schema then rather than according to package count during actual implement
Mesh, shape and size are drawn, and kenel, quantity and the ratio of each component can be a kind of random change during its actual implementation, and its
Assembly layout kenel may also be increasingly complex.
Embodiment one
As shown in figure 1, the present embodiment provides a kind of euqalizing current control circuit, the euqalizing current control circuit includes:
Voltage detection unit 10, for sampling the first voltage of the first battery and the second voltage of the second battery, and pass through
By the first voltage compared with the second voltage, the pressure difference of the first voltage and the second voltage is obtained simultaneously
Output;
Switching frequency regulates and controls unit 20, is connected with the voltage detection unit 10, for according to the voltage detection unit
The pressure difference of output, compared with setting pressure difference, and according to deviation of the pressure difference compared to the setting pressure difference
Multiple, retroregulation configuration switch frequency, so as to produce a regulating switch frequency and export;And
Switch element 30, it is connected with switching frequency regulation and control unit 20, for regulating and controlling unit according to the switching frequency
The regulating switch frequency of output, controls the disconnection switched in the switch element and closure, while realizing balancing battery voltage
Control the average current of the euqalizing current control circuit.
As an example, as shown in Fig. 2 the voltage detection unit 10 includes an error amplifier, the error amplifier
First input end be connected with the positive pole of first battery, the second input of the error amplifier and second battery
Positive pole connection, the input that the output end of the error amplifier and the switching frequency regulate and control unit is connected.
As an example, as shown in Fig. 2 switching frequency regulation and control unit 20 includes a voltage controlled frequency generator, the pressure
The input of control frequency generator is connected with the output end of the voltage detection unit, the output end of the voltage controlled frequency generator
It is connected with the switch element.
As another example, the switching frequency regulation and control unit 20 is realized using microprocessor.
As an example, as shown in Fig. 2 the switch element 30 includes switching capacity C0, first switch S1 and second switch
S2, one end of the switching capacity C0 are connected with the control terminal of the first switch S1, the other end of the switching capacity C0 with
The control terminal connection of the second switch S2, the first connection end of the first switch S1 and the positive pole of first battery connect
Connect, the second connection end of the first switch S1 is connected with the negative pole of first battery, and the first of the second switch S2 connects
Connect end to be connected with the positive pole of second battery, the second connection end of the second switch S2 and the negative pole of second battery connect
Connect, wherein, the control terminal of the first switch S1 and the second switch S2 control terminal regulate and control list by the switching frequency
The regulating switch FREQUENCY CONTROL of the output of member 20.
Embodiment two
As shown in figure 3, the present embodiment also provides a kind of euqalizing current control method, the control method includes:
Sample the first voltage of the first battery and the second voltage of the second battery, and by by the first voltage with it is described
Second voltage is compared, and obtains the pressure difference of the first voltage and the second voltage;
By the way that the pressure difference is pressed compared with setting pressure difference, and according to the pressure difference compared to the setting
The deviation multiple of difference, retroregulation configuration switch frequency, produce a regulating switch frequency;And
According to the disconnection and closure switched in the regulating switch FREQUENCY CONTROL euqalizing current control circuit, balanced electricity is realized
The average current of the euqalizing current control circuit is controlled while cell voltage.
As an example, obtaining the method for the regulating switch frequency includes:According to the deviation multiple, inverse proportion regulation and control institute
State configuration switch frequency;The regulating switch frequency meets equation below:Wherein, FreqFor regulating switch frequency,
FreqsFor configuration switch frequency, n is deviation multiple.
It should be noted thatWherein, n is deviation multiple, and Δ V is pressure difference, Δ VSTo set pressure difference.
As an example, the average current of the euqalizing current control circuit is a steady state value, its value meets that formula is as follows:I
=C × Δ VS×Freqs, wherein, I be the euqalizing current control circuit average current, C be switching capacity capacitance, Δ VS
To set pressure difference, FreqsFor configuration switch frequency.
It should be noted that by regulating and controlling to the average current value of the euqalizing current control circuit, may be implemented in
In the case of ensureing the euqalizing current control circuit security, the equilibrium of cell voltage is completed within the most short time.
Below by taking the euqalizing current control circuit of two section series-connected cells as an example, to euqalizing current controlling party described in the present embodiment
The feasibility of method carries out reverse logic analysis, specific as follows:
Formula one is obtained according to electric charge formula I × t=C × U:And for switching capacity, above-mentioned formula one can
It is transformed to formula two:I=C × Δ V/Tcyc=C × Δ V × Freq, wherein, I is the average electricity of the euqalizing current control circuit
Stream, C be switching capacity capacitance, Δ V be two batteries voltage difference, FreqFor switching frequency;It was found from above-mentioned formula two,
As switching frequency FreqOne regularly, and the change of the voltage difference Δ V between two batteries can directly result in the euqalizing current control
The change of circuital current, therefore when the voltage difference Δ V between two batteries changes, inverse proportion adjusting switch frequency can be passed through
Rate FreqRealize that the electric current of the euqalizing current control circuit is constant.
Embodiment three
As shown in figure 4, the present embodiment provides a kind of battery circuit, the battery circuit includes:
N batteries;
The charhing unit or energy-storage units being connected with the N sections battery;And
It is connected to two adjacent sections battery both ends, (N-1) as described in embodiment one individual euqalizing current control circuit;Its
In, N is the integer more than or equal to 2.
As an example, it is cascaded structure or parallel-connection structure that N, which saves the battery,.
In summary, a kind of euqalizing current control circuit, battery circuit and control method of the invention, have beneficial below
Effect:
1st, euqalizing current control circuit of the present invention not only solves the equalization problem of cell voltage, improves the control
The ability of equalization of circuit processed, also by regulating and controlling the size of current in the control circuit, improve the safety of the control circuit
Property, avoid and generated heat because electric current is excessive, and then cause the generation of safety problem.
2nd, not only circuit structure is simple for euqalizing current control circuit of the present invention, it is easy to accomplish, and occupy little space,
It is easy to reduce circuit volume.
So the present invention effectively overcomes various shortcoming of the prior art and has high industrial utilization.
The above-described embodiments merely illustrate the principles and effects of the present invention, not for the limitation present invention.It is any ripe
Know the personage of this technology all can carry out modifications and changes under the spirit and scope without prejudice to the present invention to above-described embodiment.Cause
This, those of ordinary skill in the art is complete without departing from disclosed spirit and institute under technological thought such as
Into all equivalent modifications or change, should by the present invention claim be covered.