CN219997177U

CN219997177U - Current sampling circuit, vehicle and electric equipment

Info

Publication number: CN219997177U
Application number: CN202321313009.9U
Authority: CN
Inventors: 侯贻真; 张大鹏; 周鹏飞
Original assignee: Contemporary Amperex Technology Co Ltd; Contemporary Amperex Intelligence Technology Shanghai Ltd
Current assignee: Contemporary Amperex Technology Co Ltd; Contemporary Amperex Intelligence Technology Shanghai Ltd
Priority date: 2023-05-26
Filing date: 2023-05-26
Publication date: 2023-11-10
Anticipated expiration: 2033-05-26

Abstract

The utility model discloses a current sampling circuit, a vehicle and electric equipment, wherein the current sampling circuit comprises: the shunt is connected in series on a current transmission line; the amplifying circuit is connected with two ends of the shunt and is used for amplifying and outputting the voltage difference between the two ends of the shunt; and a comparison circuit connected to the amplification circuit for comparing the amplified voltage difference with a voltage threshold and outputting a comparison result indicating overcurrent or undercurrent. The scheme utilizes the current divider, the amplifying circuit and the comparing circuit to judge the overcurrent or undercurrent of the transmission line, and has the advantages of simplicity, low cost and improved precision.

Description

Current sampling circuit, vehicle and electric equipment

Technical Field

The utility model relates to the field of electronic circuits, in particular to a current sampling circuit, a vehicle and electric equipment.

Background

In automotive control applications, typical current sampling is implemented using a shunt and current sampling chip scheme, but such sampling is typically less accurate and typically carried out on the low side. This implementation is costly if high-side high-precision sampling is to be achieved, such as with a splitter, high-side sampling chip, and analog-to-digital (Analog to Digital, AD) conversion chip.

Disclosure of Invention

In view of the above problems, the utility model provides a current sampling circuit, a vehicle and electric equipment, which can solve the problems of low precision and high cost of the current sampling mode at present.

A first aspect of an embodiment of the present utility model provides a current sampling circuit, including:

the shunt is connected in series on a current transmission line;

the amplifying circuit is connected with two ends of the shunt and used for acquiring the voltage difference between the two ends of the shunt, amplifying the voltage difference and outputting the amplified voltage difference; and

and the comparison circuit is connected with the amplifying circuit and is used for comparing the amplified voltage difference with a voltage threshold value and outputting a comparison result representing overcurrent or undercurrent.

In the technical scheme of the embodiment of the utility model, the current is sampled by connecting the current divider in series on the current transmission line, the current is converted into the voltage by the current divider, the voltage is amplified and output by the amplifying circuit, and the amplified voltage is compared with the voltage threshold value to obtain the comparison result which indicates overcurrent or undercurrent.

In some embodiments, the comparison circuit comprises:

and the first comparator is connected with the output of the amplifying circuit and is used for comparing the amplified voltage difference with an overcurrent voltage threshold value and outputting a comparison result representing overcurrent when the amplified voltage difference is larger than the overcurrent voltage threshold value.

According to the technical scheme provided by the embodiment of the utility model, the first comparator is arranged to compare the amplified voltage difference with the overcurrent voltage threshold value, so that a comparison result of whether the transmission line is overcurrent or not can be obtained according to the comparison, the scheme is simple and reliable, and the cost is low.

In some embodiments, the comparison circuit comprises:

and the second comparator is connected with the output of the amplifying circuit and is used for comparing the amplified voltage difference with a current-lack voltage threshold value and outputting a comparison result representing current lack when the amplified voltage difference is smaller than the current-lack voltage threshold value.

According to the technical scheme provided by the embodiment of the utility model, the second comparator is arranged to compare the amplified voltage difference with the undercurrent voltage threshold value, so that a comparison result of whether the transmission line is undercurrent or not can be obtained according to the comparison, the scheme is simple and reliable, and the cost is low.

In some embodiments, the amplifying circuit includes a differential amplifier having a differential input and a single-ended output, the differential input of the differential amplifier being connected to both ends of the shunt, the single-ended output of the differential amplifier being connected to the comparing circuit.

According to the technical scheme provided by the embodiment of the utility model, the common mode signal on the transmission line can be restrained by adopting the differential input and single differential amplifier, so that the accuracy of current sampling is improved.

In some embodiments, the shunt includes a resistor connected in series on the transmission line. Optionally, the shunt may further comprise a capacitance to ground in parallel with the resistor for filtering out disturbances.

In some embodiments, the apparatus further comprises a control circuit connected to an output of the amplifying circuit for outputting a current value indicative of a magnitude of a current of the transmission line according to the amplified voltage difference.

In the technical scheme of the embodiment of the utility model, a control circuit is arranged to receive the voltage output by the amplifying circuit and carry out analog-to-digital conversion on the voltage to obtain the current representing the transmission line, so that the method is simple and reliable.

In some embodiments, the control circuit is further connected to an output of the comparing circuit, and is configured to output an overcurrent alarm message or an undercurrent alarm message according to the comparison result of the overcurrent or the undercurrent.

According to the technical scheme provided by the embodiment of the utility model, the control circuit can provide the overcurrent alarm information or the undercurrent alarm information for the equipment according to the comparison result of the overcurrent or the undercurrent, so that the equipment or a user can execute related operation according to the information, and the safety of the equipment is ensured.

In some embodiments, the amplifying circuit and the comparing circuit are integrated in the same integrated circuit chip.

In the technical scheme of the embodiment of the utility model, the amplifying circuit and the comparing circuit are integrated in the same integrated circuit chip, and the unified specification is beneficial to the large-scale application of the current sampling circuit and the miniaturization of products.

In some embodiments, the transmission line comprises a dc positive line or a dc negative line.

According to the technical scheme provided by the embodiment of the utility model, the current sampling circuit can sample the current of the high-voltage side of the direct-current bus, and can also sample the low-voltage side of the direct-current bus, so that the adaptability is improved.

The second aspect of the embodiment of the utility model also provides a vehicle, which comprises a transmission line for supplying power and an automobile controller, and further comprises the current sampling circuit, wherein the current sampling circuit is connected with the transmission line and the automobile controller, and outputs a comparison result representing overcurrent or undercurrent to the automobile controller.

According to the technical scheme provided by the embodiment of the utility model, the vehicle can simply, reliably and accurately sample the current of the transmission line for supplying power in the vehicle by adopting the current sampling circuit, so that the reliability of electric equipment is improved, the normal operation of the equipment is ensured, and meanwhile, the cost of the electric equipment is also reduced.

The second aspect of the embodiment of the utility model also provides electric equipment, which comprises the current sampling circuit.

According to the technical scheme provided by the embodiment of the utility model, the electric equipment can simply, reliably and accurately sample the current by adopting the current sampling circuit, so that the reliability of the electric equipment is improved, the normal operation of the equipment is ensured, and meanwhile, the cost of the electric equipment is reduced.

The foregoing description is only an overview of the present utility model, and is intended to be implemented in accordance with the teachings of the present utility model in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present utility model more readily apparent.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

fig. 1 is a schematic diagram of a current sampling circuit according to an embodiment of the present utility model;

fig. 2 is a schematic block diagram of a current sampling circuit according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram of a current sampling circuit according to an embodiment of the present utility model;

fig. 4 is a schematic block diagram of a vehicle according to an embodiment of the present utility model.

Reference numerals in the specific embodiments are as follows:

a current sampling circuit 100, an automobile controller 200;

a shunt 110, an amplifying circuit 120, a comparing circuit 130, a control circuit 140;

differential amplifier 122. A first comparator 132, a second comparator 134;

the transmission line Vbus, the over-current reference voltage Vref1, the under-current reference voltage Vref2.

Detailed Description

Embodiments of the technical scheme of the present utility model will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present utility model, and thus are merely examples, and are not intended to limit the scope of the present utility model.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model; the terms "comprising" and "having" and any variations thereof in the description of the utility model and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present utility model, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present utility model, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the utility model. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present utility model, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of embodiments of the present utility model, the term "multi-frame" refers to more than two (including two).

In the description of the embodiments of the present utility model, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present utility model.

In automotive control applications, typical current sampling is implemented using a shunt, current sampling chip solution, which is typically less accurate and typically applied to the low side (dc bus negative) sampling. If the high-precision sampling of the high side (the positive electrode of the direct current bus) is to be realized, the high-precision sampling is realized through a current divider, a high-side sampling chip and an analog-to-digital conversion chip, and the realization scheme has higher cost. To this end, the utility model proposes to sample the current with high precision using a topology of current splitters, amplifiers and comparators, and with bi-directional (i.e. forward and reverse) overcurrent detection diagnostics.

The current sampling circuit disclosed by the utility model can be applied to conventional electric equipment, and can be particularly arranged on the positive electrode of any direct current power supply circuit of the electric equipment or on the negative electrode of any direct current power supply bus. The consumer is, for example, a vehicle controller (i.e., a drive computer: electronic Control Unit, ECU) in the vehicle, or a battery management system (Battery Management System, BMS) in the vehicle or other device having an energy storage device.

For convenience of description, the following embodiment will take a current sampling circuit according to an embodiment of the present utility model as an example.

Referring to fig. 1, fig. 1 is a schematic block diagram of a current sampling circuit according to some embodiments of the utility model. The current sampling circuit 100 includes: a shunt 110, an amplifying circuit 120 and a comparing circuit 130.

Shunt 110 is connected in series on the transmission line Vbus of the current; the amplifying circuit 120 is connected to two ends of the shunt 110, and is configured to obtain a voltage difference between two ends of the shunt 110, amplify and output the voltage difference; the comparison circuit 130 is connected to the amplification circuit 120, and is configured to compare the amplified voltage difference with a voltage threshold value and output a comparison result indicating an overcurrent or an undercurrent.

The shunt 110 is connected in series to the current transmission line Vbus, and when a current flows through the transmission line Vbus, a voltage drop is generated across the shunt 110, that is, a voltage difference across the shunt 110. Generally, in order to reduce the loss caused by the current divider 110, the actual impedance of the current divider 110 is relatively small, and the voltage drop is relatively small, so that the voltage drop needs to be amplified by the amplifying circuit 120, so that the comparing circuit 130 can identify the voltage signal, thereby improving the detection accuracy. In addition, the voltage threshold set in the comparison circuit 130 may include an upper limit value and/or a lower limit value, and thus, a result that the amplified voltage difference is greater than the upper limit value, or less than the lower limit value, or between the upper limit value and the lower limit value may be obtained by comparing the amplified voltage difference with the upper limit value and/or the lower limit value. The comparison circuit 130 outputs a comparison result indicating that the current of the transmission line Vbus is flowing, that is, the voltage difference is larger than the upper limit value, that is, the current of the transmission line Vbus is flowing, the comparison circuit 130 outputs a comparison result indicating that the current of the transmission line Vbus is flowing, that is, the voltage difference is between the upper limit value and the lower limit value, that is, the current of the transmission line Vbus is normal, and the comparison circuit 130 does not output the comparison result.

Therefore, the scheme utilizes the current divider 110, the amplifying circuit 120 and the comparing circuit 130 to judge the overcurrent or the undercurrent of the transmission line Vbus, and has simple scheme, low cost and improved precision.

Referring to fig. 2, fig. 2 is a schematic circuit diagram of a current sampling circuit 100 according to some embodiments of the utility model. In some embodiments, the comparison circuit 130 includes a first comparator 132, the first comparator 132 being connected to an output of the amplifying circuit 120 for comparing the amplified voltage difference with an over-current voltage threshold and outputting a comparison result indicative of an over-current when the amplified voltage difference is greater than the over-current voltage threshold.

The overcurrent voltage threshold is the upper limit value described above. Specifically, the non-inverting input terminal of the first comparator 132 and the output of the amplifying circuit 120, the inverting input terminal of the first comparator 132 is connected to the over-current reference voltage Vref1, and when the amplified voltage difference output by the amplifying circuit 120 is greater than the over-current reference voltage Vref1, a high level is output to indicate that the current of the transmission line Vbus flows.

By providing the first comparator 132 to compare the amplified voltage difference with the threshold value of the over-current voltage, a comparison result of whether the transmission line Vbus is over-current can be obtained according to the comparison, and the scheme is simple and reliable, and the cost is low.

With continued reference to fig. 2, in some embodiments, the comparing circuit 130 includes a second comparator 134, where the second comparator 134 is connected to an output of the amplifying circuit 120, and is configured to compare the amplified voltage difference with the undercurrent voltage threshold, and output a comparison result indicating undercurrent when the amplified voltage difference is less than the undercurrent voltage threshold.

The undercurrent voltage threshold is the lower limit value. Specifically, the inverting input terminal of the second comparator 134 and the output of the amplifying circuit 120, the non-inverting input terminal of the first comparator 132 is connected to the undercurrent reference voltage Vref2, and when the amplified voltage difference output by the amplifying circuit 120 is smaller than the undercurrent reference voltage Vref2, a high level is output to indicate the current undercurrent of the transmission line Vbus.

It can be seen that, based on the above two embodiments, the comparison circuit 130 may include a first comparator 132 and a second comparator 134, which have two output terminals for outputting a comparison result indicating an overcurrent and a comparison result indicating an undercurrent, respectively. The scheme is simple and reliable, and the cost is low.

With continued reference to fig. 2, in some embodiments, the amplifying circuit 120 includes a differential amplifier 122 having a differential input (end) and a single-ended output (end), the differential input of the differential amplifier 122 is connected to two ends of the shunt 110, and the single-ended output (end) of the differential amplifier 122 is connected to the comparing circuit 130. The differential amplifier 122 with differential input and single-ended output can suppress the common mode signal on the transmission line Vbus, thereby improving the accuracy of current sampling.

In some embodiments, the shunt 110 comprises a resistor connected in series on the transmission line Vbus. Optionally, the shunt 110 may also include a capacitance to ground in parallel with the resistor for filtering out disturbances.

Referring to fig. 3, fig. 3 is a schematic circuit diagram of a current sampling circuit 100 according to some embodiments of the utility model. In some embodiments, the current sampling circuit 100 further includes a control circuit 140, the control circuit 140 being connected to the output of the amplifying circuit 120 for outputting a current value representing the magnitude of the current of the transmission line Vbus according to the amplified voltage difference.

Specifically, the control circuit 140 may perform analog-to-digital conversion on the amplified voltage difference, thereby obtaining a current value representing the magnitude of the current of the transmission line Vbus. It is understood that the control circuit 140 may be an analog-to-digital conversion chip, or may be a microprocessor (Microcontroller Unit, MCU) with analog-to-digital conversion function, for example, a single chip microcomputer may be used. And the voltage is subjected to analog-to-digital conversion to obtain the current which represents the transmission line Vbus, so that the method is simple and reliable.

Optionally, the control circuit 140 may further include a display screen, or be connected to the display screen, so as to output the current value to the display screen to directly display the current value, so that the user can know the current magnitude of the transmission line Vbus at this time.

In some embodiments, the control circuit 140 is further connected to an output of the comparing circuit 130, for outputting the over-current alarm information or the under-current alarm information according to a comparison result of the over-current or the under-current.

For example, the control circuit 140 includes a microprocessor, which can directly use the over-current alarm information or the under-current alarm information to control the device to execute related operations, so as to ensure the safety of the device. The user may control the device to perform the related operation according to the overcurrent alarm information or the undercurrent alarm information output by the control circuit 140.

In some embodiments, the amplifying circuit 120 and the comparing circuit 130 are integrated in the same integrated circuit chip. The integrated circuit is integrated in the same integrated circuit chip, and the unified specification is beneficial to the large-scale application of the current sampling circuit 100 and the miniaturization of products.

In some embodiments, the transmission line Vbus is a dc positive line or a dc negative line. That is, the current sampling circuit 100 of the present utility model can be used for sampling the low-voltage end current of the dc transmission line Vbus, and also can be used for sampling the high-voltage end current of the dc transmission line Vbus, and the circuit is widely applied and is not affected by high and low voltages.

With continued reference to fig. 3, the current sampling circuit 100 provided by the present utility model adopts a scheme of a current divider 110, a comparator, an amplifier and a Microprocessor (MCU) to perform current sampling and overcurrent and undercurrent protection; the differential voltage at two ends of the shunt 110 is amplified by an amplifier and then converted into single-ended voltage; comparing the detected value with a limit value through a comparator, and giving an alarm if overcurrent or undercurrent occurs; in addition, the voltage amplified by the amplifier enters an AD pin of the microprocessor to carry out analog-to-digital conversion, and high-precision sampling is realized through a Kalman filtering algorithm; compared with the scheme of a common high-side sampling chip and an AD conversion chip, the circuit scheme has lower cost.

With continued reference to fig. 4, the second aspect of the embodiment of the present utility model further provides a vehicle 10, where the vehicle 10 includes a transmission line Vbus and an automobile controller (ECU) 200 for supplying power, and the above-mentioned current sampling circuit 100, and the current sampling circuit 100 is connected to the transmission line Vbus and the automobile controller 200, and is configured to output a comparison result indicating an overcurrent or an undercurrent to the automobile controller 200.

The transmission line Vbus for power supply in the vehicle may be any power supply transmission line, such as a transmission line from a power supply battery to a power supply module, or a transmission line from a power supply module to any load. The current sampling circuit 100 is configured to output a comparison result indicating an overcurrent or an undercurrent to the vehicle controller 200, and the vehicle controller 200 may perform a corresponding action, such as disconnecting a transmission line for power supply, sounding an alarm, or the like, according to the comparison result.

In some embodiments, the control circuit 140 in the current sampling circuit may include the vehicle controller 200, and may also include a microprocessor connected to the vehicle controller 200.

A third aspect of an embodiment of the present utility model further provides a powered device, including the current sampling circuit 100 as described above. By adopting the current sampling circuit 100, the electric equipment can simply, reliably and accurately sample current, the reliability of the electric equipment is improved, the normal operation of the equipment is ensured, and meanwhile, the cost of the electric equipment can be reduced.

The electric equipment is common fuel oil vehicles, electric vehicles, energy storage equipment, motor equipment, robot equipment, electronic products and the like.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present utility model. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

In the embodiments provided by the present utility model, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the electronic device embodiments described above are merely illustrative. For example, the division of a module or unit is merely a logical function division, and there may be another division manner when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other forms.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present utility model may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model, and are intended to be included in the scope of the present utility model.

Claims

1. A current sampling circuit, comprising:

the shunt is connected in series on a current transmission line;

2. The current sampling circuit of claim 1 wherein said comparison circuit comprises:

3. The current sampling circuit of claim 1 wherein said comparison circuit comprises:

4. The current sampling circuit of claim 1 wherein the amplifying circuit comprises a differential amplifier having a differential input, a single ended output, the differential input of the differential amplifier being connected across the shunt, the single ended output of the differential amplifier being connected to the comparing circuit.

5. The current sampling circuit of claim 1 wherein said shunt comprises a resistor, said resistor being connected in series on said transmission line.

6. The current sampling circuit according to any one of claims 1 to 5, further comprising a control circuit connected to an output of the amplifying circuit for outputting a current value representing a magnitude of a current of the transmission line according to the amplified voltage difference.

7. The current sampling circuit of claim 6 wherein said control circuit is further coupled to an output of said comparison circuit for outputting an over-current alarm message or an under-current alarm message based on said comparison of over-current or under-current.

8. The current sampling circuit according to any one of claims 1 to 5, wherein said amplifying circuit and said comparing circuit are integrated in the same integrated circuit chip.

9. The current sampling circuit according to any one of claims 1 to 5, wherein the transmission line includes a direct current positive electrode line or a direct current negative electrode line.

10. A vehicle comprising a transmission line for supplying power and a vehicle controller, further comprising a current sampling circuit as claimed in any one of claims 1 to 9, connected to the transmission line and the vehicle controller, for outputting a comparison result representing an overcurrent or undercurrent to the vehicle controller.

11. A powered device comprising a current sampling circuit according to any of claims 1-9.