Battery Fuel Gauging Circuit

Abstract

The embodiment of the present disclosure provides a battery power measurement circuit, which includes: a power supply, a voltage sampling resistor module, a current sampling resistor module, a differential compensation module, a common mode inductor, a relay, and a battery; the first end of the voltage sampling resistor module is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the voltage sampling resistor module is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; the first end of the current sampling resistor module is respectively connected to the second end of the common mode inductor and the first end of the differential compensation module; the second end of the current sampling resistor module is connected to the second end of the differential compensation module; the third end of the common mode inductor is connected to the first end of the relay; the fourth end of the common mode inductor is connected to the positive terminal of the battery; and the second end of the relay is connected to the negative terminal of the battery.

Description

Technical Field

[0001] The present disclosure relates to the technical field of batteries, and in particular to a battery capacity measurement circuit. Background Art

[0002] Currently, when a battery is charged and discharged, it is necessary to measure the amount of electricity in the battery during the charging and discharging process. During the measurement, a metering chip is usually used for measurement.

[0003] In order to accurately collect the battery power during the charging and discharging process, it is usually necessary to use a metering chip to collect the voltage at both ends of the battery and the current in the circuit. Since there are usually common-mode inductors, relays and other devices at the front end of the battery, when the metering chip is used to directly collect the voltage at both ends of the battery, the EMI (Electromagnetic Interference) interference inside the power supply will bypass the common-mode inductor through the metering chip, causing interference to the circuit, and the voltage spike when the power module is hot-swapped may damage the metering chip.

[0004] In order to prevent these problems, in the related art, the metering chip is powered independently and communicates with the control chip inside the power module through an isolation chip to complete the battery power metering, but this increases the complexity of the circuit power metering circuit. Summary of the invention

[0005] The embodiments of the present disclosure provide a battery power measurement circuit to solve the problem of high complexity of the battery power measurement circuit caused by the need to independently power the measurement chip in the related art.

[0006] In a first aspect, an embodiment of the present disclosure provides a battery capacity measurement circuit, the circuit comprising:

[0007] Power supply, voltage sampling resistor module, current sampling resistor module, differential compensation module, common mode inductor, relay, and battery;

[0008] Wherein, the first end of the voltage sampling resistor module is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the voltage sampling resistor module is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module;

[0009] The first end of the current sampling resistor module is connected to the second end of the common mode inductor and the first end of the differential compensation module respectively; the second end of the current sampling resistor module is connected to the second end of the differential compensation module;

[0010] The third end of the common mode inductor is connected to the first end of the relay; the fourth end of the common mode inductor is connected to the positive terminal of the battery;

[0011] The second end of the relay is connected to the negative terminal of the battery;

[0012] The power source is used to charge the battery or receive discharge from the battery;

[0013] When the battery is charged or discharged, the differential compensation module is used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at a preset position of the voltage sampling resistor module the same as the voltage value of the battery; the voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module are used to measure the power of the battery.

[0014] At least one of the above technical solutions provided by the embodiments of the present invention can achieve the following technical effects:

[0015] In the circuit provided by the embodiment of the present invention, when the battery is charged or discharged, current flows into the current sampling resistor module and generates a voltage on the current sampling resistor module. The differential compensation module can be used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at the preset position of the voltage sampling resistor module the same as the voltage value of the battery. After the differential compensation voltage is output, the voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module can be used to measure the circuit of the battery.

[0016] Therefore, in the circuit provided by the embodiment of the present invention, the metering chip can directly measure the voltage value at the preset position of the voltage sampling resistor module and the current value of the current sampling resistor module to complete the battery power measurement. Since there is no need to directly collect the voltage across the battery, it can avoid EMI interference from the power supply, and there is no need to independently power the metering chip, thereby effectively solving the technical problem of high circuit complexity caused by the need to independently power the metering chip in the related art, and effectively reducing the circuit complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate one or more embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

[0018] Figure 1 One of the schematic diagrams of a battery capacity measurement circuit provided by an embodiment of the present invention;

[0019] Figure 2A second schematic diagram of a battery capacity measurement circuit provided by an embodiment of the present invention;

[0020] Figure 3 A third schematic diagram of a battery capacity measurement circuit provided by an embodiment of the present invention;

[0021] Figure 4 A fourth schematic diagram of a battery capacity measurement circuit provided by an embodiment of the present invention;

[0022] Figure 5 A fifth schematic diagram of a battery capacity measurement circuit provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the technical parties in this technical field better understand the technical aspects of one or more embodiments of the present disclosure, and to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in combination with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0025] See also Figure 1 , Figure 1 One of the schematic diagrams of a battery capacity measurement circuit provided by an embodiment of the present invention is as follows: Figure 1 As shown, the battery capacity measurement circuit includes: a power supply, a voltage sampling resistor module, a current sampling resistor module, a differential compensation module, a common mode inductor, a relay, and a battery;

[0026] Wherein, the first end of the voltage sampling resistor module is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the voltage sampling resistor module is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module;

[0027] The first end of the current sampling resistor module is connected to the second end of the common mode inductor and the first end of the differential compensation module respectively; the second end of the current sampling resistor module is connected to the second end of the differential compensation module;

[0028] The third end of the common mode inductor is connected to the first end of the relay; the fourth end of the common mode inductor is connected to the positive terminal of the battery;

[0029] The second terminal of the relay is connected to the negative terminal of the battery;

[0030] The power source is used to charge the battery, or receive the discharge of the battery;

[0031] When the battery is charging or discharging, the differential compensation module is used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at the preset position of the voltage sampling resistor module the same as the voltage value of the battery; the voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module are used to measure the battery power.

[0032] like Figure 1 As shown, the connection relationship of each component or module in the circuit shown in the embodiment of the present invention is as follows: the positive terminal of the power supply is connected to the first end of the voltage sampling resistor module and the first end of the common mode inductor, and the second end of the voltage sampling resistor module is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; the second end of the common mode inductor is respectively connected to the first end of the current sampling resistor module and the first end of the differential compensation module; the third end of the common mode inductor is connected to the first end of the relay; the fourth end of the common mode inductor is connected to the positive terminal of the battery; the second end of the relay is connected to the negative terminal of the battery; the second end of the current sampling resistor module is connected to the second end of the differential compensation module.

[0033] Based on the above connection relationship, when the power supply is used to charge or discharge the battery, the battery can be charged and discharged through the common mode inductor and the relay. In order to obtain the current power of the battery without being interfered by the EMI inside the battery, the embodiment of the present invention proposes that the voltage at both ends of the battery can be determined according to the voltage at the front end of the common mode inductor, so as to measure the battery power through the voltage at the front end of the common mode inductor.

[0034] In order to make the voltage at the front end of the common mode inductor consistent with the voltage at both ends of the battery, in the circuit of the embodiment of the present invention, when the battery is charged, the differential compensation module can be used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at the preset position of the voltage sampling resistor module the same as the voltage value at both ends of the battery. The voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module can be used to measure the battery power.

[0035] Therefore, in the circuit shown in the embodiment of the present invention, the voltage value at the preset position of the voltage sampling resistor module and the current value flowing through the current sampling resistor module can be measured by a metering device or a metering component, such as a metering chip, and the battery power can be measured according to the measured voltage value and current value. Of course, the charge and discharge power of the battery can also be determined according to the measured voltage value and current value.

[0036] In a circuit shown in an embodiment of the present invention, the voltage sampling resistor module may specifically include a first voltage sampling resistor, a second voltage sampling resistor, and a third voltage sampling resistor, and the connection relationship between them in the circuit is:

[0037] The first end of the first voltage sampling resistor is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the first voltage sampling resistor is respectively connected to the first end of the second voltage sampling resistor and the first end of the third voltage sampling resistor; the second end of the second voltage sampling resistor is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; the second end of the third voltage sampling resistor is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module.

[0038] Based on the above connection relationship, when the battery is charged or discharged, the first voltage sampling resistor, the second voltage sampling resistor, and the third voltage sampling resistor can be used to determine the differential compensation coefficient when the differential compensation module performs differential compensation processing on the voltage generated on the current sampling resistor module; wherein the differential compensation coefficient can be used to adjust the voltage generated on the current sampling resistor module so that the voltage generated on the third voltage sampling resistor is the same as the voltage at both ends of the battery. Therefore, when the metering chip is used to measure the voltage value at a preset position to determine the voltage value at both ends of the battery, the voltage value generated on the third voltage sampling resistor can be measured.

[0039] In the above circuit shown in the embodiment of the present invention, the current sampling resistor module may include a current sampling resistor, and the connection relationship between the current sampling resistor and other components in the circuit is: the first end of the current sampling resistor is respectively connected to the second end of the common mode inductor and the first end of the differential compensation module; the second end of the current sampling resistor is connected to the second end of the differential compensation module.

[0040] Based on the above connection relationship, when the battery is charging or discharging, the current sampling resistor can be used to determine the above differential compensation coefficient.

[0041] In the above circuit shown in the embodiment of the present invention, the differential compensation module may specifically include a differential compensator and a first differential resistor, a second differential resistor, a third differential resistor and a fourth differential resistor, and their connection relationship in the circuit is:

[0042] The first end of the first differential resistor is respectively connected to the second end of the current sampling resistor, the second end of the second voltage sampling resistor, and the second end of the third voltage sampling resistor; the second end of the first differential resistor is respectively connected to the first end of the fourth differential resistor and the first end of the differential compensator; the first end of the second differential resistor is respectively connected to the second end of the common mode inductor and the first end of the current sampling resistor; the second end of the second differential resistor is respectively connected to the second end of the differential compensator and the first end of the third differential resistor; the second end of the third differential resistor is respectively connected to the third end of the differential compensator, the second end of the second voltage sampling resistor, and the second end of the third voltage sampling resistor; the second end of the fourth differential resistor is respectively connected to the second end of the second voltage sampling resistor and the second end of the third voltage sampling resistor.

[0043] Based on the above connection relationship, when the battery is charged or discharged, the first differential resistor and the fourth differential resistor can be matching resistors of the differential compensator; and the second differential resistor and the third differential resistor can be used to determine the above differential compensation coefficient. For example, the ratio of the resistance value of the third differential resistor to that of the second differential resistor can be determined as the above differential compensation coefficient.

[0044] In the above circuit shown in the embodiment of the present invention, the first terminal and the second terminal of the differential compensator may be input terminals; the third terminal of the differential compensator may be an output terminal. In addition, the above differential compensation coefficient may be a positive value or a negative value. Specifically, when the battery is charging, the differential compensation coefficient may be a negative value; when the battery is discharging, the differential compensation coefficient may be a positive value.

[0045] like Figure 2 As shown, it is a second schematic diagram of a battery capacity measurement circuit provided by an embodiment of the present invention. In the circuit shown in the embodiment of the present invention, resistors R1-R3 can represent a voltage sampling resistor module, specifically, resistor R1 can represent the above-mentioned first voltage sampling resistor; resistor R2 can represent the above-mentioned second voltage sampling resistor; resistor R3 can represent the above-mentioned third voltage sampling resistor; resistor R4 can represent the above-mentioned current sampling resistor; U2 can represent a differential amplifier; resistors R5-R8 and differential amplifier U2 can represent a differential compensation module, specifically, resistor R5 can represent a first differential resistor; resistor R6 can represent a second differential resistor; resistor R7 can represent a third differential resistor; resistor R8 can represent a fourth differential resistor; L1 can represent a common mode inductor; K1 can represent a relay; B1 can represent a battery; a bidirectional ACDC module can represent an output direct current or alternating current, and can be used to represent a power supply.

[0046] For the convenience of description, Figure 3As shown, the voltage between the voltage Vo+ at both ends of the power supply and GND can be expressed as Vo; the voltage between Vbat+ and Vbat- at both ends of the battery is expressed as Vbat; the voltage across the current sampling resistor is expressed as VR4; the current flowing through the resistor R4 is expressed as Io, wherein Io=VR4 / R4; the metering chip can measure the voltage value of the voltage sampling resistor R3 and the current value flowing through the current sampling resistor R4, and realize the metering of the battery power according to the measured voltage value and current value.

[0047] When the battery is charging, Figure 2 and Figure 3 The circuit shown, and Figure 4 The current flow diagram shown can be expressed as follows:

[0048] P 充电 =Vbat*I o (1)

[0049] Vo=Vbat+(R i1 +R i2 )*I o (2)

[0050] Among them, P 充电 is the charging power of the battery; R i1 is the impedance between Vo+ and Vbat+; R i2 is the impedance between GND and Vbat-.

[0051] From formula (2), we can get the following formula:

[0052] Vbat=Vo-(R i1 +R i2 )*I o (3)

[0053] According to formulas (1)-(3), we can get formulas (4) and (5):

[0054] P 充电 =[Vo-(R i1 +R i2 )*I o]*I o (4)

[0055]

[0056] Among them, Vo_sam can represent the voltage value generated on the resistor R3; K can represent the differential compensation coefficient of the differential compensation module, that is, the differential compensation multiple when the voltage generated on the current sampling resistor module is differentially compensated. When the battery is charging, the differential compensation coefficient can be a negative value to compensate for the impedance R i1 and R i2 The voltage drop caused by the

[0057] In the embodiment of the present invention, the differential compensation coefficient K may be:

[0058]

[0059] According to formulas (5) and (6), the following formula can be obtained:

[0060]

[0061] From formula (7), by setting appropriate voltage sampling resistors, current sampling resistors, and differential compensation modules in the circuit, appropriate resistance values ​​and impedance values ​​can be obtained, and the impedance R i1 and R i2 The voltage drop caused by the voltage drop is well compensated so that the voltage value of Vo_sam can be the same as the voltage across the battery.

[0062] Correspondingly, when the battery is discharged, Figure 2 and Figure 3 The circuit shown, and Figure 5 The current flow diagram shown can be expressed as follows:

[0063] P 放电 =Vbat*I o (8)

[0064] Vbat=Vo+(R i1 +R i2 )*I o (9)

[0065] Among them, P 放电 is the discharge power of the battery. According to formulas (8) and (9), the following formula can be obtained:

[0066] P 放电 =[Vo+(R i1 +R i2 )*I o]*I o (10)

[0067]

[0068] When the battery is discharged, the differential compensation coefficient K can be positive to compensate for the impedance R i1 and R i2 The voltage drop caused by the

[0069] In the embodiment of the present invention, the differential compensation coefficient K may be:

[0070]

[0071] According to formulas (11) and (12), the following formula can be obtained:

[0072]

[0073] From formula (13), it can be seen that by setting appropriate voltage sampling resistors, current sampling resistors, and differential compensation modules in the circuit, appropriate resistance values ​​and impedance values ​​can be obtained, and the impedance R i1 and R i2 The voltage drop caused by the voltage drop is well compensated so that the voltage value of Vo_sam can be the same as the voltage across the battery.

[0074] In the circuit provided by the embodiment of the present invention, when the battery is charged or discharged, current flows into the current sampling resistor module and generates a voltage on the current sampling resistor module. The differential compensation module can be used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at the preset position of the voltage sampling resistor module the same as the voltage value of the battery. After the differential compensation voltage is output, the voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module can be used to measure the circuit of the battery.

[0075] Therefore, in the circuit provided by the embodiment of the present invention, the metering chip can directly measure the voltage value at the preset position of the voltage sampling resistor module and the current value of the current sampling resistor module to complete the battery power measurement. Since there is no need to directly collect the voltage across the battery, it can avoid EMI interference from the power supply, and there is no need to independently power the metering chip, thereby effectively solving the technical problem of high circuit complexity caused by the need to independently power the metering chip in the related art, and effectively reducing the circuit complexity.

[0076] The above description is only an embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the scope of the claims of the present disclosure.

Claims

1. A battery capacity measurement circuit, characterized in that: The circuit comprises: Power supply, voltage sampling resistor module, current sampling resistor module, differential compensation module, common mode inductor, relay, and battery; Wherein, the first end of the voltage sampling resistor module is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the voltage sampling resistor module is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; The first end of the current sampling resistor module is connected to the second end of the common mode inductor and the first end of the differential compensation module respectively; the second end of the current sampling resistor module is connected to the second end of the differential compensation module; The third end of the common mode inductor is connected to the first end of the relay; the fourth end of the common mode inductor is connected to the positive terminal of the battery; The second end of the relay is connected to the negative terminal of the battery; The power source is used to charge the battery or receive discharge from the battery; When the battery is charged or discharged, the differential compensation module is used to perform differential compensation processing on the voltage generated on the current sampling resistor module, and output a differential compensation voltage that makes the voltage value at a preset position of the voltage sampling resistor module the same as the voltage value of the battery; the voltage value at the preset position of the voltage sampling resistor module and the current value of the current flowing into the current sampling resistor module are used to measure the power of the battery; The voltage sampling resistor module includes a first voltage sampling resistor, a second voltage sampling resistor, and a third voltage sampling resistor; The first end of the first voltage sampling resistor is respectively connected to the positive terminal of the power supply and the first end of the common mode inductor; the second end of the first voltage sampling resistor is respectively connected to the first end of the second voltage sampling resistor and the first end of the third voltage sampling resistor; The second end of the second voltage sampling resistor is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; The second end of the third voltage sampling resistor is respectively connected to the negative terminal of the power supply and the second end of the differential compensation module; When the battery is charged or discharged, the first voltage sampling resistor, the second voltage sampling resistor, and the third voltage sampling resistor are used to determine the differential compensation coefficient when the differential compensation module performs differential compensation processing on the voltage generated on the current sampling resistor module; wherein the differential compensation coefficient is used to make the voltage generated on the third voltage sampling resistor the same as the voltage at both ends of the battery after adjusting the voltage generated on the current sampling resistor module; The current sampling resistor module includes a current sampling resistor; The first end of the current sampling resistor is connected to the second end of the common mode inductor and the first end of the differential compensation module respectively; the second end of the current sampling resistor is connected to the second end of the differential compensation module; When the battery is charged or discharged, the current sampling resistor is used to determine the differential compensation coefficient; The differential compensation module includes a differential compensator and a first differential resistor, a second differential resistor, a third differential resistor and a fourth differential resistor; The first end of the first differential resistor is respectively connected to the second end of the current sampling resistor, the second end of the second voltage sampling resistor, and the second end of the third voltage sampling resistor; the second end of the first differential resistor is respectively connected to the first end of the fourth differential resistor and the first end of the differential compensator; The first end of the second differential resistor is respectively connected to the second end of the common mode inductor and the first end of the current sampling resistor; the second end of the second differential resistor is respectively connected to the second end of the differential compensator and the first end of the third differential resistor; The second end of the third differential resistor is respectively connected to the third end of the differential compensator, the second end of the second voltage sampling resistor, and the second end of the third voltage sampling resistor; The second end of the fourth differential resistor is respectively connected to the second end of the second voltage sampling resistor and the second end of the third voltage sampling resistor; When the battery is charged or discharged, the first differential resistor and the fourth differential resistor are matching resistors of the differential compensator; and the second differential resistor and the third differential resistor are used to determine the differential compensation coefficient.

2. The circuit according to claim 1, characterized in that The first end and the second end of the differential compensator are input ends; and the third end of the differential compensator is an output end.

3. The circuit according to claim 2, characterized in that The differential compensation coefficient is a positive value or a negative value; When the battery is being charged, the differential compensation coefficient is a negative value; when the battery is being discharged, the differential compensation coefficient is a positive value.

Images