CN114935680A - Shunt superposition detection circuit and power supply protection device - Google Patents
Shunt superposition detection circuit and power supply protection device Download PDFInfo
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- CN114935680A CN114935680A CN202210524080.5A CN202210524080A CN114935680A CN 114935680 A CN114935680 A CN 114935680A CN 202210524080 A CN202210524080 A CN 202210524080A CN 114935680 A CN114935680 A CN 114935680A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
- H02J7/61—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements against overcharge
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
- H02J7/62—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements against overcurrent
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
- H02J7/63—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements against overdischarge
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Abstract
本发明提供一种分流叠加检测电路和电源保护装置，所述电路包括：多条分流支路，每条分流支路接于总电流输入端和总电流输出端之间，每条分流支路均串联一电流检测电阻，每条分流支路的电流检测电阻的两端各串联一电压叠加电阻后并接于同一电压检测端的正负极；其中，电压检测端的电压值为每条分流支路形成的压降叠加值，电压检测端的电压值与多条分流支路的电流值之和为线性比例关系，每条分流支路的电流值为总电流值的任意比例。本发明所述分流叠加检测电路成本低、方案简单，多条分流支路输出可使得电源内部均衡发热和散热，可靠性和安全性高。
The invention provides a shunt superposition detection circuit and a power supply protection device. The circuit includes: a plurality of shunt branches, each shunt branch is connected between a total current input end and a total current output end, and each shunt branch has a A current detection resistor is connected in series, and both ends of the current detection resistor of each shunt branch are connected in series with a voltage superimposed resistor and then connected to the positive and negative electrodes of the same voltage detection terminal; wherein, the voltage value of the voltage detection terminal is formed by each shunt branch. The superposition value of the voltage drop, the sum of the voltage value of the voltage detection terminal and the current value of multiple shunt branches is a linear proportional relationship, and the current value of each shunt branch is an arbitrary ratio of the total current value. The shunt superposition detection circuit of the present invention has low cost and simple scheme, and the output of multiple shunt branches can make the internal heating and heat dissipation of the power supply balanced, and the reliability and safety are high.
Description
Technical Field
The invention relates to the technical field of circuits, in particular to a shunt superposition detection circuit and a power supply protection device.
Background
At present, the output end of a battery cell or other power supply devices is a total current loop, and the total current can be obtained by directly detecting the total current loop. However, as the power of the application device is continuously increased, the heat generated inside the battery cell or inside the other power supply devices is concentrated and is not easy to dissipate, so that the local temperature is too high, and the user experience and the service life of the device are influenced.
To improve this problem, the inside of the battery cell or other power supply devices are divided into multiple paths of input and output, and each path of current is arbitrarily distributed, so that the detection of the total current will face a serious challenge. The current solution is to design a current detection circuit for each branch circuit to obtain a current of each branch circuit, then design a current collection detection circuit to collect the current of each branch circuit, and finally obtain a total current, and calculate an electric quantity value according to the total current. However, this solution involves a complex application of software and hardware, which is costly and inefficient.
Disclosure of Invention
The invention provides a shunt superposition detection circuit and a power supply protection device, which are used for solving the problems of high software and hardware cost and low benefit caused by calculating the total current of each branch circuit in the prior art.
In a first aspect, the present invention provides a shunt superposition detection circuit, which has a total current input terminal and a total current output terminal, wherein the total current input terminal and the total current output terminal are both connected to an internal or external power device, the shunt superposition detection circuit has a voltage detection terminal, and the shunt superposition detection circuit includes:
each shunt branch is connected between the total current input end and the total current output end, each shunt branch is connected with a current detection resistor in series to detect the current value of the branch, two ends of the current detection resistor of each shunt branch are connected with a voltage superposition resistor in series and then connected with the positive electrode and the negative electrode of the voltage detection end, and the voltage superposition resistor is used for forming voltage drop at the voltage detection end;
the voltage value of the voltage detection end is a voltage drop superposition value formed by each shunt branch, the sum of the voltage value of the voltage detection end and the current values of the shunt branches is in a linear proportional relation, and the current value of each shunt branch is in any proportion to the total current value.
In an embodiment of the present invention, if the resistances of the current detection resistors of each shunt branch are equal, the linear proportional relationship is expressed by the following equation:
Uo＝(1/n)*R*(I1+I2+I3+I4+...+In)；
wherein, Uo represents the voltage value of the voltage detection end, n represents n shunt branches, R represents the resistance value of the current detection resistor, I1-In represents the current value of the 1 st to nth shunt branches respectively, and n is a natural number greater than 1.
In an embodiment of the present invention, the shunt superposition detection circuit further includes a plurality of loads, and the current detection resistor of each shunt branch is connected in series with a load and then connected to the total current output terminal.
In an embodiment of the present invention, the plurality of shunting branches include a first shunting branch and a second shunting branch, the first shunting branch is connected in series with a first current detection resistor, the second shunting branch is connected in series with a second current detection resistor, two ends of the first current detection resistor are respectively connected in series with a voltage superposition resistor and then connected in parallel with an anode and a cathode of the voltage detection terminal, and two ends of the second current detection resistor are respectively connected in series with a voltage superposition resistor and then connected in parallel with an anode and a cathode of the voltage detection terminal.
In an embodiment of the present invention, the voltage value of the voltage detection terminal and the sum of the current value of the first shunt branch and the current value of the second shunt branch are in a linear proportional relationship, and if the resistance value of the first current detection resistor is equal to the resistance value of the second current detection resistor, the linear proportional relationship is expressed by the following formula:
Uo＝0.5a*(I1+I2)；
wherein Uo represents a voltage value of the voltage detection terminal, a represents a resistance value of the first current detection resistor or the second current detection resistor, I1 represents a current value of the first shunt branch, and I2 represents a current value of the second shunt branch.
In an embodiment of the invention, a resistance value of the current detection resistor is equal to a resistance value of the voltage superposition resistor.
In an embodiment of the invention, a resistance value of the current detection resistor is smaller than a resistance value of the voltage superposition resistor, the resistance value of the current detection resistor is in a milliohm level, and the resistance value of the voltage superposition resistor is in an ohm level.
In an embodiment of the present invention, the current detection resistor or the voltage superposition resistor is a series-parallel resistor, a series-parallel capacitor, a series-parallel inductor, or an equivalent resistor combined with any one or more of a resistor, a capacitor, and an inductor.
In an embodiment of the invention, the current detection resistor is a precision resistor.
In a second aspect, the present invention further provides a power protection device, including the shunt superposition detection circuit according to any one of the first aspects.
In an embodiment of the present invention, the power protection apparatus further includes a battery cell body, a first connector, a second connector, and a fuel gauge, wherein two shunt branches of the battery cell body are respectively connected to the first connector and the second connector, and the shunt superposition detection circuit is connected between the first connector and the second connector; the electricity meter is connected with the positive electrode and the negative electrode of the voltage detection end and used for measuring the voltage value of the voltage detection end and calculating total current according to the linear proportional relation of the voltage value of the voltage detection end and the sum of the current values of all the shunt branches to obtain the electric quantity value of the voltage protection device, and the total current is the sum of the current values of all the shunt branches.
According to the shunting and overlapping detection circuit and the power supply protection device, the total current can be randomly shunted through the symmetrical design of the equivalent resistor, and then the voltage drop formed by each shunting branch is overlapped to obtain the total current.
Drawings
In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other embodiments can be obtained according to the drawings without creative efforts.
FIG. 1 is a multi-path schematic diagram of a shunt and stack detection circuit provided by the present invention;
FIG. 2 is an equivalent circuit diagram of FIG. 1 in a first case;
FIG. 3 is a simplified circuit diagram of FIG. 2;
FIG. 4 is an equivalent circuit diagram of FIG. 3;
FIG. 5 is a simplified circuit diagram of FIG. 4;
FIG. 6 is an equivalent circuit diagram of FIG. 1 in a second case;
FIG. 7 is a circuit diagram of FIG. 6;
FIG. 8 is an equivalent circuit diagram of FIG. 7;
FIG. 9 is a simplified circuit diagram of FIG. 8;
FIG. 10 is a schematic diagram of two principles of a shunt overlap detection circuit according to the present invention;
FIG. 11 is a schematic diagram of a multi-pass application provided by an embodiment of the present invention;
FIG. 12 is a schematic diagram of one of two applications provided by an embodiment of the present invention;
fig. 13 is a second schematic diagram of two applications provided by the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terms "first," "second," and the like in the description and claims of the present invention and in the preceding drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein.
The problem that local temperature is too high due to concentrated heating and difficult heat dissipation inside the battery core or inside other power supply devices can be solved by the aid of the multipath input and output of the battery core or other power supply devices, but due to the multipath input and output, the current of each branch of related software and hardware is calculated in the prior art, and then the current of each branch is collected to obtain the total current.
Therefore, in order to solve the problem, the present invention provides a shunt and overlap detection circuit and a power protection device, which can, through the symmetrical design of the current detection resistor and the voltage overlap resistor, shunt the total current according to any proportion, then overlap the voltage drop formed by each shunt branch to obtain the voltage of the voltage detection end, and calculate the total current according to the linear relationship between the voltage of the voltage detection end and the sum of the current values of each shunt branch.
Compared with the prior art, the shunting and superposing detection circuit has the advantages of low cost, simple scheme, balanced heating and heat dissipation in the power supply due to the output of the plurality of shunting branches, high reliability and safety and the like.
The shunt superposition detection circuit and the power supply protection device of the present invention are described below with reference to fig. 1 to 13.
Fig. 1 is a schematic diagram of a multi-path principle of a shunt superposition detection circuit provided by the present invention, as shown in fig. 1. The utility model provides a reposition of redundant personnel stack detection circuitry, has total current input end and total current output end, total current input end with total current output end all connects In an external power supply device's inside or outside, reposition of redundant personnel stack detection circuitry includes many reposition of redundant personnel branch roads (I1 ~ In, n is for being greater than 1 natural number), and every reposition of redundant personnel branch road connects In between total current input end and the total current output end. Illustratively, on the circuit structure, In order to balance heat generation and heat dissipation, the current can be divided according to any proportion by arranging a plurality of current dividing branches (I1-In). The total current I is always split by each branch (I1-In), i.e., I total — I1+ I2+ I3+. + In.
Illustratively, each shunt branch is connected in series with a current detection resistor, and the current detection resistor is used for detecting the current value of the branch. For example, the first shunt branch I1 is connected in series with a current detection resistor R1, the second shunt branch I2 is connected in series with a current detection resistor R2, the third shunt branch I3 is connected in series with a current detection resistor R3, and the fourth shunt branch I4 is connected in series with a current detection resistor R4. The nth shunt branch In is connected In series with a current detection resistor Rn.
Illustratively, an input of the total current iital is connected to a negative terminal of an external power source, and a positive terminal of the external power source is connected to an output of the total current iital. The shunting and superposing detection circuits I1-In further include a plurality of loads, such as the loads 1-n shown In fig. 1, and the current detection resistor of each shunting branch is connected In series with a load and then connected to the output end of the total current itotal. For example, the first shunting branch I1 is connected In series with a current detection resistor R1, then connected In series with a load 1, and then connected to the output terminal of the total current iduct, the second shunting branch I2 is connected In series with a current detection resistor R2, then connected In series with a load 2, and then connected to the output terminal of the total current iduct, and so on, the nth shunting branch In is connected In series with a current detection resistor Rn, then connected In series with a load n, and then connected to the output terminal of the total current iduct.
Exemplarily, the external power supply is composed of array cells, and may be composed of n × n array cells connected in series and in parallel, that is, the cells may be divided into n paths for output, so that the inside of the cells generates heat and dissipates heat in a balanced manner, and reliability and safety are improved. It can be understood that the external power supply may also be formed by connecting a plurality of battery cells in parallel, so the number and arrangement of the battery cells are not limited in the present invention.
For example, two ends of the current detection resistor of each shunt branch are respectively connected in series with a voltage superposition resistor and then connected in parallel with the positive electrode and the negative electrode of the same voltage detection end, and the voltage superposition resistor is used for forming a voltage drop at the voltage detection end.
For example, the first shunting branch I1 is connected in series with a current detection resistor R1, and is connected in series with a voltage superposition resistor R1 and a voltage superposition resistor R2 at two ends of the current detection resistor R1, and then is connected to the positive and negative poles (+, -) of the voltage detection terminal Uo.
The second shunt branch I2 is connected in series with a current detection resistor R2, and is connected in series with a resistor voltage superposition R3 and a voltage superposition resistor R4 at two ends of the current detection resistor R2 and then connected with the anode and the cathode (+, -) of the same voltage detection end UO.
The third shunt branch I3 is connected in series with a current detection resistor R3, and is connected in series with a voltage superposition resistor R5 and a voltage superposition resistor R6 at two ends of the current detection resistor R3 and then connected with the positive and negative poles (+, -) of the same voltage detection end Uo.
The fourth shunting branch I4 is connected in series with a current detection resistor R4, and is connected in series with a voltage superposition resistor R7 and a voltage superposition resistor R8 at two ends of the current detection resistor R4 and then connected to the positive and negative poles (+, -) of the same voltage detection terminal Uo.
The nth shunt branch In is connected In series with a current detection resistor Rn, and is respectively connected In series with a voltage superposition resistor r (2n-1) and a voltage superposition resistor r (2n) at two ends of the current detection resistor Rn and then connected with the anode and the cathode (+, -) of the same voltage detection end UO.
Illustratively, the current detection resistors (R1 to Rn) or the voltage superposition resistors (R1 to R (2n)) may be equivalent resistors, such as a series-parallel resistor, a series-parallel capacitor, a series-parallel inductor, or the like, or may be equivalent to a current detection resistor or a voltage superposition resistor by combining any one or more of the resistors, capacitors, and inductors. Since in theory, for example, the inductor is an inductor, but in practice it can be equivalent to a resistor + inductor, since the copper lines of the inductor itself have a resistance. The current detection resistor is generally required to pass a large current, for example, a current with a current value of 10A is required to pass in the current fast charging, so the resistance value of the current detection resistor is generally small, for example, substantially within 5 milliohms. Therefore, the present invention may be applied with an inductance equivalent to a resistance. The equivalent resistance of the present invention is not limited to this form of resistance.
For example, a certain resistor Rx and a certain capacitor Cx connected in parallel are equivalent to a certain resistor Ry connected in series, and since the capacitor Cx is connected with alternating current and isolated from direct current, and a general battery is direct current, the effect of the capacitor Cx is small, so that the two forms are basically equivalent. As can be seen from fig. 1, the voltage value of the voltage detection terminal Uo is a voltage drop superposition value formed by each shunt branch, and through the following theoretical calculation, it can be seen that the sum of the voltage value of the voltage detection terminal Uo and the current value of each shunt branch (i.e., I1+ I2+ I3+ I4+.. + In) is In a linear proportional relationship, and the current value of each shunt branch can be shunted according to any proportion of the total current value, so that the current value of a specific proportion can be set according to the actual shunt branch.
For example, assuming that the resistance values of the current detection resistors of each shunt branch are equal, i.e., R1-R2-R3-R4-Rn-R, the linear proportional relationship is expressed as:
Uo＝(1/n)*R*(I1+I2+I3+I4+...+In)；
wherein Uo represents a voltage value of the voltage detection terminal, n represents n shunt branches, R represents a resistance value of the current detection resistor, I1 to In represent current values of 1 st to nth shunt branches, respectively, and n is a natural number greater than 1.
The linear proportional equation is derived by theoretical calculation.
Wherein, I is total I1+ I2+ I3+ I4+ … + In;
suppose that:
r＝r1＝r2＝r3＝r4＝…＝r(2n-1)＝r(2n)；
R＝R1＝R2＝R3＝R4＝…＝Rn；
the current arrows shown in fig. 1 are in the reference direction, and if the current arrows are in the opposite direction to that shown in fig. 1, this current value is negative. The following formula derivation is done in two cases:
in the first case:
assuming that the resistances of the resistors R1, R2, R3, R4.. Rn are much smaller than those of the resistors R1, R2, R3, and r4... R (2n), the resistances of the current f1 ═ f2 ═ f3 ═ f4 ═ … … ═ f (2n) ═ 0 (very close to 0 and set to 0), that is, the resistances of the current detection resistors R1, R2, R3, and R4.. Rn are preferably in milliohm range; the resistance values of the voltage superposition resistors r1, r2, r3, r4... r (2n) are preferably in the ohm level, even in the K ohm level.
Fig. 2 is an equivalent circuit diagram of fig. 1, as shown in fig. 2. Assume that the currents I1, I2, I3, I4... In form voltage drops of U1, U2, U3, U4... Un at the resistors R1, R2, R3, R4.. Rn, respectively.
Fig. 2 is simplified to fig. 3, and an equivalent fig. 4 is obtained according to thevenin's theorem and norton's theorem. And further simplifies fig. 4 to fig. 5. Among them, the Thevenin theorem and the Nuodon theorem are commonly used circuit simplification methods.
Making Is1+ Is2+ Is3+ Is4+ - + Isn;
rs＝(r1+r2)//(r3+r4)//...//(r(2n-1)+r(2n))；
then:
Uo＝Is*rs。
by combining the above fig. 2 to 5, the following results were obtained:
U1＝I1*R1，U2＝I2*R2，U3＝I3*R3，U4＝I4*R4，...，Un＝In*Rn；
Is1＝U1/(r1+r2)，Is2＝U2/(r3+r4)，...，Isn＝Un/(r(2n-1)+r(2n))。
then:
according to the following assumptions:
r＝r1＝r2＝r3＝r4＝…＝r(2n-1)＝r(2n)；
R＝R1＝R2＝R3＝R4＝…＝Rn；
the following results were obtained:
Is＝(I1+I2+I3+I4+…+In)*R/(2*r)；
rs＝(2*r)/n；
then:
Uo＝Is*rs＝(1/n)*R*(I1+I2+I3+I4+…+In)。
therefore, by the theoretical derivation, the voltage value Uo of the detection voltage end of the shunt superposition detection circuit of the present invention and I1+ I2+ I3+ I4+ … + In have a linear relationship, that is:
Uo＝(1/n)*R*(I1+I2+I3+I4+…+In)。
transforming the above formula to obtain:
i total ═ I11+ I2+ I3+ I4+ … + In ═ Uo × n/R.
The voltage Uo can be directly detected by the ammeter, and the ammeter can automatically correct the voltage Uo to obtain the value of Itotal according to the value of Itotal.
Therefore, In the above formula, when R1 ═ R2 ═ R3 ═ R4 ═ … ═ Rn ═ 2m Ω, the precise resistance actually detected by the fuel gauge is (2/n) m Ω, but at the same time, the detection of I1+ I2+ I3+ I4+ … + In by the fuel gauge is also satisfied.
Preferably, for the convenience of theoretical derivation calculation, the present invention assumes that the current detection resistance of each shunt branch is equal, and the voltage superposition resistance of each shunt branch is equal, i.e. the present invention assumes that the current detection resistance of each shunt branch is equal to the voltage superposition resistance of each shunt branch
R1, R2, R3, R4, …, Rn; R1R 2R 3R 4R … R (2n-1) R (2n), resistances R1, R2, R3, R4 … … Rn are much smaller than R1, R2, R3, R4 … … R (2 n).
It should be noted that the resistors R1, R2, R3, R4, …, and Rn may also be unequal, for example, if R1 is n times of the other current detection resistors, and the resistance values of the other current detection resistors are R, if n is3, the above equation may be expressed as:
U1＝I1*R1，U2＝I2*R2，U3＝I3*R3，U4＝I4*R4，...，Un＝In*Rn；
obtaining:
U1＝I1*3R，U2＝I2*R2，U3＝I3*R3，U4＝I4*R4，...，Un＝In*Rn；
the following results were obtained:
Is1＝U1/(r1+r2)，Is2＝U2/(r3+r4)，...，Isn＝Un/(r(2n-1) +r(2n))；
r1, r2, r3, r4, r (2 n);
R＝3*R＝R2＝R3＝R4...＝Rn；
obtaining:
Is＝(3*I1+I2+I3+I4+...+In)*R/(2*r)；
rs＝(2*r)/n；
then:
Uo＝(1/n)*R*(3*I1+I2+I3+I4+…+In)。
it can be seen that when the current sensing resistances of each of the branches are different, a coefficient, such as the above current I1 multiplied by a coefficient 3, is multiplied on the current value of each branch to indicate whether the current of the branch is amplified or reduced.
In practical applications, the resistance value R of the current detection resistor Rx of one of the shunt branches may be used as a reference, and the resistance values of the current detection resistors Ry of the other shunt branches are multiples of the resistance Rx, such as 0.1 times (i.e., 0.1R), 0.007 times (i.e., 0.007R), 5 times (i.e., 5R), and the like.
In the second case:
assuming that the resistances R1, R2, R3, R4 … … Rn and R1, R2, R3, and R4 … … R (2n) are close to each other, f1 ═ f2 ═ f3 ═ f4 ═ f … … ═ f (2n) is not 0.
Using the superposition theorem of circuit analysis, let only one of I1, I2, I3, I4 … … In be other than 0, i.e.: only one of load 1, load 2, load 3, load 4, … …, load n, is not off, and the remaining full off current is 0.
When I1 is not 0, I2 ═ I3 ═ I4 ═ I … … ═ In ═ 0, the circuit shown In fig. 6 is obtained.
In fig. 6, r4, r6 and r8 … … r (2n) are connected in parallel to simplify the circuit shown in fig. 7, wherein Z1 is r4// r6// r8// ·.// r (2 n).
In fig. 7, (R2+ R3), (R3+ R5), (R4+ R7) … … (Rn + R (2n-1)) are connected in parallel, simplifying the circuit shown in fig. 8, wherein,
G1+H1＝(R2+r3)//(R3+r5)//(R4+r7)//......//(Rn+r(2n-1))。
the circuit shown in fig. 9 is obtained by sorting the above fig. 8.
Let only one of I1, I2, I3 … … In be other than 0, i.e.: only one of load 1, load 2, load 3, … …, load n, is not off, and the remaining full off current is 0.
Let I1 not be 0, I2 ═ I3 ═ I4 ═ I … … ═ In ═ 0, to give:
let x1, x2, x3 … … xn and y1, y2, y3 … … yn be constant coefficients, I1, I2, I3 … … In and J1, J2, J3 … … Jn be currents, and the following forms are obtained by analogy:
let I1 not be 0, I2 ═ I3 ═ I4 ═ I … … ═ In ═ 0, to give: uo1 ═ I1 × 1+ J1 × y 1;
let I2 not be 0, I1 ═ I3 ═ I4 ═ I … … ═ In ═ 0, to give: uo2 ═ I2 × 2+ J2 × y 2;
let I3 not be 0, I1 ═ I2 ═ I4 ═ I … … ═ In ═ 0, to give: uo3 ═ I3 × 3+ J3 × y 3;
......；
let In not be 0, I1-I2-I3- … … -I (n-1) -0, to obtain: uon ═ In × n + Jn × yn;
and (3) superposition theorem: uo total ═ Uo1+ Uo2+ Uo3+ … … Uon;
the practical application proposal is as follows:
r＝r1＝r2＝r3＝r4＝……＝r(2n-1)＝r(2n)，R＝R1＝R2＝R3＝R4＝……＝Rn；
the following form is obtained:
uo total ═ R (1/n) × (I1+ I2+ I3+ I4+ … … + In).
The shunt superposition detection circuit according to the invention is described below by way of an embodiment with two shunt branches.
Fig. 10 is a schematic diagram of two principles of the shunt superposition detection circuit provided by the present invention, as shown in fig. 10. The circuit diagram shown in fig. 9 is equivalent to the circuit diagram shown in fig. 10.
Illustratively, a shunt superposition detection circuit is connected to the power source Us. Fig. 10 shows two shunt branches, each of which is connected in series to a load, i.e., the first shunt branch I1 is connected in series to a load 1, and the second shunt branch I2 is connected in series to a load 2.
Illustratively, the power source Us may represent a power source of a battery cell, the loads 1 and 2 may represent a mobile phone or other electric equipment, and the shunt I1 and the shunt I2 represent a large current discharged through two branches.
Fig. 10 shows two shunt branches, that is, a first shunt branch I1 and a second shunt branch I2, where an output end of a total current icotal is connected to the first shunt branch I1 and the second shunt branch I2, the first shunt branch I1 is connected in series to a current detection resistor R1, the second shunt branch I2 is connected in series to a current detection resistor R2, two ends of a current detection resistor R1 of the first shunt branch I1 are connected in series to a voltage superposition resistor RS1 and a voltage superposition resistor RS3, respectively, and then connected in parallel to a positive pole and a negative pole of a voltage detection terminal Uo, and two ends of a current detection resistor R2 of the second shunt branch I2 are connected in series to a voltage superposition resistor RS2 and a voltage superposition resistor RS4, respectively, and then connected in parallel to a positive pole and a negative pole of the voltage detection terminal Uo. The current detection resistor R1 is used for detecting the current value of the first shunt branch I1, and the current detection resistor R2 is used for detecting the current value of the second shunt branch I2. The voltage superposition resistor RS1 and the voltage superposition resistor RS3 are used for forming voltage drop at the voltage detection end UO, the voltage superposition resistor RS2 and the voltage superposition resistor RS4 are also used for forming voltage drop at the voltage detection end UO, and the voltage detection end UO is provided with a positive electrode and a negative electrode.
As shown in fig. 10, the first branch I1 is shunted into currents I3 and I4 through voltage superposition resistors RS1 and RS3, so as to form a voltage drop at the voltage detection terminal Uo.
In fig. 10, RI1, RI2, RI3, and RI4 represent internal resistances of wires, the current detection resistors R1 and R2 are precision resistors, and the voltage superposition resistors RS1 to RS4 are common detection resistors. The voltage detection terminal Uo is a voltage that can be output to the electricity meter to calculate the total current.
As can be seen from fig. 10, the voltage value of the voltage detection terminal Uo is a voltage drop superposition value formed by the first shunt branch I1 and the second shunt branch I2, and it is known that the voltage value of the voltage detection terminal Uo and the sum of the current values of the first shunt branch I1 and the second shunt branch I2 (i.e., I1+ I2) are in a linear proportional relationship through the following theoretical calculation, and the current values of the first shunt branch I1 and the second shunt branch I2 can be split according to any proportion of the total current value, so that it is also convenient to set the current values of a specific proportion according to the actual shunt branches.
For example, assuming that the resistances of the current detection resistors of the first shunt branch I1 and the second shunt branch I2 are equal, i.e., R1 ═ R2 ═ a, the linear proportional relationship is expressed by the following equation:
Uo＝0.5a*(I1+I2)；
wherein Uo represents a voltage value of the voltage detection terminal, a represents a resistance value of the current detection resistor, I1 represents a current value of the first shunt branch, and I2 represents a current value of the second shunt branch.
The linear proportional equation is derived by theoretical calculation.
Wherein: the values of Us, load 1, load 2, R1, R2, and RS1, RS2, RS3, RS4 are known, and the relationship between Uo and I1, I2 is found.
Let R1-R2-R, RS 1-RS 2-RS 3-RS 4-b, obtained from kirchhoff's law:
I1*Rl1+I3*(RS1+RS2)＝I2*Rl2；---------------------------------------①
I3*(RS1+RS2)+(I2+I3)*R2＝(I1-I3)*R1+I4*(RS3+RS4)；---------②
Uo+I3*RS1＝(I1-I3)*R1+I4*RS3；-------------------------------------③
obtaining:
obtained by the following steps:
substituting I3 into I4 to obtain:
substituting the fourth step and the fifth step into the third step to obtain:
finishing to obtain:
the final coefficients of I1 and I2 are all constant values, and UO is linearly proportional to I1 and I2:
if 1: rl1 ═ Rl 2;
if 2: rl1 and Rl2 are internal resistances of the lead, and the internal resistance is very small and is set to be 0;
if 1 or if 2, then:
if 3: r1 ═ R2 ═ a, RS1 ═ RS2 ═ RS3 ═ RS4 ═ b, then:
Uo＝0.5a(I1+I2)。
when the current measuring device is applied, preferably, R1 ═ R2, RS1 ═ RS2 ═ RS3 ═ RS4, and when a ═ R1 ═ R2 ═ 2m Ω, the precision resistance actually detected by the fuel gauge IC or other current and voltage detection IC is 1m Ω, and the detection of I1 and I2 by the fuel gauge is satisfied.
The shunting and overlapping detection circuit can be applied to any power supply protection device, such as a lithium battery protection device in a mobile phone.
The following is an embodiment of the shunt superposition detection circuit applied to the field of mobile phones.
Fig. 11 is a schematic diagram of a multi-path application provided by the embodiment of the present invention, as shown in fig. 11. The left power supply in fig. 11 is a matrix cell of n × n, the voltage value of the voltage detection terminal is detected by the fuel gauge IC or other current and voltage detection ICs to obtain a corresponding voltage value, and then the voltage value of the voltage detection terminal and the total current are known to be in a linear relationship according to the above-mentioned formula, so as to calculate the value of the total current. In the figure, a rectangular dashed line frame is a protection circuit, for example, a protection circuit with a disconnection protection function, such as overcharge, overdischarge, overcurrent, short circuit, and the like, can be added to a large current loop.
Fig. 12 is a schematic diagram of one of two applications provided by the embodiment of the present invention, and fig. 13 is a schematic diagram of a second application provided by the embodiment of the present invention, as shown in fig. 12 and fig. 13. The power protection device shown in fig. 12 includes a battery cell body, and in order to prevent the internal temperature of the battery cell body from being too high, fig. 12 shows that the battery cell body is divided into two paths of current outputs, that is, I1 and I2 represent two paths of large currents on the left and right.
The large-current charging and discharging connector J1 and the connector J2 shown in fig. 12 correspond to the connector J1 and the connector J2 in fig. 13, and the current sum detection line in fig. 12 corresponds to the current sum detection line in fig. 13.
Illustratively, the power protection device comprises the shunt superposition detection circuit.
Exemplarily, the power protection device further includes a cell body, a first connector, a second connector, and an electricity meter, two shunt branches of the cell body are respectively connected to the first connector and the second connector, the shunt superposition detection circuit is two shunt branches, and includes a current detection resistor R1, a current detection resistor R2, a voltage superposition resistor RS1, a voltage superposition resistor RS2, a voltage superposition resistor RS3, and a voltage superposition resistor RS4, and a connection relationship between the current detection resistor and the voltage superposition resistor may be shown in fig. 10, which is not repeated herein.
Illustratively, the power protection device further comprises a current overcurrent detection module, and two ends of the current detection resistor R1 are connected with a current overcurrent detection module, and are used for detecting whether the shunt branch is overcurrent to realize overcurrent protection; the two ends of the current detection resistor R2 are also connected to a current over-current detection module, and are also used to detect whether the shunt branch is over-current to implement over-current protection.
Illustratively, the fuel gauge is connected to the positive electrode and the negative electrode of the voltage detection end Uo, and is configured to measure a voltage value of the voltage detection end Uo, and calculate a total current according to a linear proportional relationship in which a sum of the voltage value of the voltage detection end Uo and a current value of each shunt branch is a sum of the current values of each shunt branch.
For example, as can be seen from the above description, if Uo is 0.5a (I1+ I2), then the current value of I1+ I2, i.e., I1+ I2 is Uo/0.5a, can be obtained from the voltage Uo measured by the electricity meter, and since the electricity meter itself has a coefficient of 1/0.5a, the electricity meter can correct Uo by itself, so as to obtain the total current imetal I is I1+ I2, and then the electric quantity value of the mobile phone battery can be calculated from the current value of I1+ I2.
It should be noted that the shunt branch of the shunt superposition detection circuit of the present invention may be disposed at different positions according to different circuit structures, and may also be disposed with any multi-channel input/output, which is not limited to the manner provided in the above embodiments.
Further, the shunt superposition detection circuit of the present invention may also be applied to other power protection devices, and the other power protection devices are not limited to the above two shunt branches, but may also be a multi-path shunt branch, and the multi-path shunt branch may shunt according to any proportion.
In addition, the shunt superposition inspection circuit can be integrated on the PCB protection board, so that the design space required by the protection board can be reduced, the multi-layer complexity of PCB design can be reduced, for example, the shunt superposition inspection circuit is beneficial to avoiding positive and negative superposition between PCB layers, reducing the risk of short circuit of a positive electrode and a negative electrode, and improving the reliability and the safety of products.
In summary, the shunt and overlap detection circuit provided by the invention can enable the power supply to uniformly heat and radiate the inside of the power supply through the multi-path shunt branch, avoid focusing heating, improve the reliability and safety of the power supply and the power supply protection board, and prolong the service life of the power supply.
Moreover, the shunt superposition detection circuit provided by the invention is simple in circuit and low in cost through the symmetrical design of pure resistors; after the total current is divided according to any proportion, voltage drops formed by the current of each branch circuit are superposed, the total current can be calculated, and complex software and hardware design is not required to be additionally provided.
Furthermore, the shunt superposition detection circuit provided by the invention can be used for randomly setting multiple independent large-current input and output according to the actual circuit structure, improving the charging efficiency of a large-capacity power supply and reducing the charging time so as to meet the requirements of quick charging and endurance of consumers. Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a reposition of redundant personnel stack detection circuitry, has total current input end and a total current output end, total current input end with total current output end all connects in an external power supply device's inside or outside, its characterized in that, reposition of redundant personnel stack detection circuitry has a voltage detection end, reposition of redundant personnel stack circuit includes:
each shunt branch is connected between the total current input end and the total current output end, each shunt branch is connected with a current detection resistor in series for detecting the current value of the branch, two ends of the current detection resistor of each shunt branch are connected with a voltage superposition resistor in series and then connected with the positive electrode and the negative electrode of the voltage detection end in parallel, and the voltage superposition resistor is used for forming voltage drop at the voltage detection end;
the voltage value of the voltage detection end is a voltage drop superposition value formed by each shunt branch, the sum of the voltage value of the voltage detection end and the current values of the shunt branches is in a linear proportional relation, and the current value of each shunt branch is in any proportion to the total current value.
2. The shunt superposition detection circuit according to claim 1, wherein if the resistances of the current detection resistors of each shunt branch are equal, the linear proportional relationship is expressed by the following equation:
Uo＝(1/n)*R*(I1+I2+I3+I4+...+In)；
wherein Uo represents a voltage value of the voltage detection terminal, n represents n shunt branches, R represents a resistance value of the current detection resistor, I1 to In represent current values of the 1 st to nth shunt branches, respectively, and n is a natural number greater than 1.
3. The shunt superposition detection circuit according to claim 1, further comprising a plurality of loads, wherein the current detection resistor of each shunt branch is connected in series with a load and then connected to the total current output terminal.
4. The shunt superposition detection circuit according to claim 1, wherein the shunt branches include a first shunt branch and a second shunt branch, the first shunt branch is connected in series with a first current detection resistor, the second shunt branch is connected in series with a second current detection resistor, two ends of the first current detection resistor are respectively connected in series with a voltage superposition resistor and then connected in parallel with the positive and negative electrodes of the voltage detection terminal, and two ends of the second current detection resistor are respectively connected in series with a voltage superposition resistor and then connected in parallel with the positive and negative electrodes of the voltage detection terminal.
5. The shunt superposition detection circuit according to claim 4, wherein the voltage value of the voltage detection terminal is in a linear proportional relationship with the sum of the current value of the first shunt branch and the current value of the second shunt branch, and if the resistance value of the first current detection resistor is equal to the resistance value of the second current detection resistor, the linear proportional relationship is expressed by the following formula:
Uo＝0.5a*(I1+I2)；
wherein Uo represents a voltage value of the voltage detection terminal, a represents a resistance value of the first current detection resistor or the second current detection resistor, I1 represents a current value of the first shunt branch, and I2 represents a current value of the second shunt branch.
6. The shunt superposition detection circuit according to claim 1, wherein the resistance value of the current detection resistor is equal to the resistance value of the voltage superposition resistor.
7. The shunt superposition detection circuit according to claim 1, wherein the resistance of the current detection resistor is smaller than the resistance of the voltage superposition resistor, the resistance of the current detection resistor is in milliohm level, and the resistance of the voltage superposition resistor is in ohm level.
8. The shunt superposition detection circuit according to claim 1, wherein the current detection resistor or the voltage superposition resistor is an equivalent resistor employing a series-parallel resistor, a series-parallel capacitor, a series-parallel inductor, or any one or more of a resistor, a capacitor, and an inductor; the current detection resistor is a precision resistor.
9. A power supply protection device comprising the shunt superposition detection circuit according to any one of claims 1 to 8.
10. The power protection device of claim 9, further comprising a cell body, a first connector, a second connector, and a fuel gauge, wherein two shunt branches of the cell body are respectively connected to the first connector and the second connector, and the shunt superposition detection circuit is connected between the first connector and the second connector; the electricity meter is connected with the positive electrode and the negative electrode of the voltage detection end and used for measuring the voltage value of the voltage detection end and calculating total current according to the linear proportional relation of the voltage value of the voltage detection end and the sum of the current values of all the shunt branches to obtain the electric quantity value of the power supply protection device, and the total current is the sum of the current values of all the shunt branches.
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