CN115656622A - Charging power measuring device and method for charging cable - Google Patents

Charging power measuring device and method for charging cable Download PDF

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CN115656622A
CN115656622A CN202211091884.7A CN202211091884A CN115656622A CN 115656622 A CN115656622 A CN 115656622A CN 202211091884 A CN202211091884 A CN 202211091884A CN 115656622 A CN115656622 A CN 115656622A
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voltage
charging
resistor
reference voltage
measuring circuit
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江勇
彭立钟
江��一
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Shenzhen Weijie Zhongzhi Technology Co ltd
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Shenzhen Weijie Zhongzhi Technology Co ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles

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Abstract

The invention discloses a charging power measuring device and method for a charging cable, and relates to the technical field of power measurement. The charging device comprises an MCU processor, a charging voltage measuring circuit, a charging current measuring circuit, an external reference voltage measuring circuit and an external reference voltage generator, wherein the MCU processor is electrically connected with the charging voltage measuring circuit, the charging current measuring circuit and the external reference voltage measuring circuit, the charging current measuring circuit is electrically connected with a charging power supply and the external reference voltage generator, the charging power supply is electrically connected with the charging voltage measuring circuit and the external reference voltage generator, and the MCU processor is used for determining the charging voltage of the charging power supply, the reference voltage of the external reference voltage generator and the charging current of the charging power supply and determining the charging power of a charging cable between the charging power supply and the charging device based on the charging voltage of the charging power supply and the charging current of the charging power supply. The device and the method disclosed by the invention can be used for more accurately measuring the charging power of the charging cable.

Description

Charging power measuring device and method for charging cable
Technical Field
The invention belongs to the technical field of power measurement, and particularly relates to a charging power measurement device and method for a charging cable.
Background
In the process of charging the device to be charged through the charging power supply, if the charging power of the charging power supply is lower than the rated charging power of the device to be charged, the charging speed is reduced, the charging time is prolonged, and if the charging power of the charging power supply is higher than the rated charging power of the device to be charged, the device to be charged may be burnt due to overhigh charging power. Therefore, in order to ensure that the charging power of the charging power supply meets the rated charging power requirement of the device to be charged, it is necessary to measure the charging power of the charging cable between the charging power supply and the charging device.
At present, in order to measure the charging power of a charging cable between a charging power supply and a charging device, a common mode is to set one circuit for measuring a charging voltage and one circuit for measuring a charging current, the charging current measuring circuit usually takes a certain reference voltage as a reference during measurement, the accuracy of the charging current measurement is affected by the accuracy of the reference voltage, and the accuracy of the reference voltage is usually low, so the calculation accuracy of the charging power is usually not very high, and the measured data may have a large deviation from the actual situation.
Therefore, how to provide an effective solution to improve the measurement accuracy of the charging power has become an urgent problem in the prior art.
Disclosure of Invention
The present invention is directed to a charging power measuring device and method for a charging cable, so as to solve the above problems in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a charging power measuring apparatus for a charging cable, comprising: the charging device comprises an MCU processor, a charging voltage measuring circuit, a charging current measuring circuit, an external reference voltage measuring circuit and an external reference voltage generator, wherein the MCU processor is respectively and electrically connected with the charging voltage measuring circuit, the charging current measuring circuit and the external reference voltage measuring circuit;
the MCU processor is used for determining the charging voltage of the charging power supply based on an internal reference voltage in the processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter in the processor, a second digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the analog-digital converter, and a resistance value of a divider resistor used for voltage division in the charging voltage measuring circuit;
determining a reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the external reference voltage measuring circuit;
determining a charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a fourth digital voltage value obtained by converting a third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor for dividing voltage in the charging current measuring circuit, a reference voltage of the external reference voltage generator, and a resistance value of a current detecting resistor in the charging current measuring circuit; and
and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
In one possible design, the charging voltage measuring circuit includes a first resistor, a second resistor, a third resistor and a first capacitor, one end of the first resistor is connected to the charging power supply, the other end of the first resistor is connected to one end of the second resistor, the other end of the second resistor is grounded, one end of the third resistor is connected between the first resistor and the second resistor, the other end of the third resistor is connected to the MCU processor, one end of the first capacitor is grounded, and the other end of the first capacitor is connected between the third resistor and the MCU processor;
the first resistor and the second resistor are divider resistors used for voltage division in the charging voltage measuring circuit.
In one possible design, the external reference voltage measuring circuit includes a fourth resistor, a fifth resistor, a sixth resistor, and a second capacitor, one end of the fourth resistor is connected to the MCU processor, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fifth resistor is grounded, one end of the sixth resistor is connected between the fourth resistor and the fifth resistor, the other end of the sixth resistor is connected to the external reference voltage generator, one end of the second capacitor is connected between the sixth resistor and the external reference voltage generator, and the other end of the second capacitor is grounded;
the fourth resistor and the fifth resistor are voltage dividing resistors used for voltage division in the external reference voltage measuring circuit.
In one possible design, the charging current measuring circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a third capacitor, one end of the ninth resistor is connected to the external reference voltage measuring circuit, the other end of the ninth resistor is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to the MCU processor, one end of the eighth resistor, and ground, the other end of the eighth resistor is grounded, one end of the seventh resistor is connected between the ninth resistor and the tenth resistor, the other end of the seventh resistor is connected to the MCU processor, one end of the third capacitor is connected between the ninth resistor and the MCU processor, and the other end of the third capacitor is grounded;
the ninth resistor and the tenth resistor are voltage dividing resistors used for voltage division in the charging current measuring circuit, and the eighth resistor is a current detection resistor in the charging current measuring circuit.
In one possible design, the charging power measuring device for the charging cable further includes a power display circuit, and the power display circuit is electrically connected with the MCU processor.
In one possible design, the MCU processor is specifically configured to, when determining the charging voltage of the charging power supply based on an internal reference voltage inside the processor, a first digital voltage value obtained by converting the internal reference voltage by an analog-to-digital converter ADC inside the processor, a first digital voltage value obtained by converting a first sampled voltage of the charging power supply sampled by the charging voltage measurement circuit by an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the charging voltage measurement circuit:
calculating a first sampling voltage of the charging power supply based on the internal reference voltage, the first digital voltage value, and the second digital voltage value;
and calculating the charging voltage of the charging power supply based on the first sampling voltage of the charging power supply and the resistance value of a voltage dividing resistor used for voltage division in the charging voltage measuring circuit.
In one possible design, the MCU processor is specifically configured to, when determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a second sampled voltage of the external reference voltage generator sampled by the external reference voltage measurement circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the external reference voltage measurement circuit:
calculating a second sampling voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, and the third digital voltage value;
and calculating the reference voltage of the external reference voltage generator based on the second sampling voltage of the external reference voltage generator and the resistance value of a voltage dividing resistor for dividing the voltage in the external reference voltage measuring circuit.
In one possible design, the MCU processor, when configured to determine the charging current of the charging power supply based on a fourth digital voltage value obtained by converting the internal reference voltage, the first digital voltage value, a third sampled voltage of the external reference voltage measurement circuit sampled by the charging current measurement circuit through an analog-to-digital converter, a resistance value of a voltage dividing resistor in the charging current measurement circuit for voltage division, a reference voltage of an external reference voltage generator, and a resistance value of a current detection resistor in the charging current measurement circuit, is specifically configured to:
calculating a third sampling voltage of the external reference voltage measurement circuit based on the internal reference voltage, the first digital voltage value, and the fourth digital voltage value;
calculating a voltage difference between both ends of the current detection resistor based on a third sampling voltage of the external reference voltage measurement circuit, a resistance value of a voltage division resistor for voltage division in the charging current measurement circuit, and a reference voltage of the external reference voltage generator;
and calculating the charging current of the charging power supply based on the voltage difference between the two ends of the current detection resistor and the resistance value of the current detection resistor.
In one possible design, the voltage of the charging power supply is 5-48V.
In a second aspect, the present invention provides a charging power measurement method, which is applied to the MCU processor of the charging power measurement apparatus for a charging cable according to any of the first aspects above, and the method includes:
determining the charging voltage of the charging power supply based on an internal reference voltage in a processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter (ADC) in the processor, a first digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the ADC, and a resistance value of a voltage dividing resistor for dividing the voltage in the charging voltage measuring circuit;
determining a reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a second digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measurement circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the external reference voltage measurement circuit;
determining a charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor for dividing voltage in the charging current measuring circuit, a reference voltage of the external reference voltage generator, and a resistance value of a current detecting resistor in the charging current measuring circuit;
and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
Has the advantages that:
the charging power measurement scheme provided by the invention comprises the steps that an MCU processor, a charging voltage measurement circuit, a charging current measurement circuit, an external reference voltage measurement circuit and an external reference voltage generator are arranged, the MCU processor is respectively and electrically connected with the charging voltage measurement circuit, the charging current measurement circuit and the external reference voltage measurement circuit, the charging current measurement circuit is respectively and electrically connected with a charging power supply and the external reference voltage generator, and the charging power supply is respectively and electrically connected with the charging voltage measurement circuit and the external reference voltage generator, wherein the MCU processor is used for determining the charging voltage of the charging power supply based on an internal reference voltage in the processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter in the processor, a second digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measurement circuit through the analog-digital converter, and a resistance value of a divider resistor for dividing voltage in the charging voltage measurement circuit; determining the reference voltage of the external reference voltage generator based on the third digital voltage value obtained by converting the internal reference voltage, the first digital voltage value, the second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through the analog-digital converter and the resistance value of a divider resistor for dividing the voltage in the external reference voltage measuring circuit; determining the charging current of the charging power supply based on a fourth digital voltage value obtained by converting an internal reference voltage, a first digital voltage value, a third sampling voltage of an external reference voltage measuring circuit sampled by a charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor used for voltage division in the charging current measuring circuit, the reference voltage of an external reference voltage generator and the resistance value of a current detecting resistor in the charging current measuring circuit; and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply. Thus, when the charging power of the charging cable between the charging power supply and the charging equipment is measured, the voltage of the external reference voltage measuring circuit is measured by using the internal reference voltage of the MCU processor, so that the precision of the charging current is irrelevant to the external reference voltage of the external reference voltage generator and is relevant to the precision of the internal reference voltage of the MCU processor, and the precision of the internal reference voltage of the MCU processor is obviously higher than the external reference voltage of the external reference voltage generator, thereby improving the measuring precision of the charging current and further more accurately measuring the charging power of the charging cable.
Drawings
Fig. 1 is a schematic block diagram of a charging power measurement apparatus for a charging cable according to an embodiment of the present disclosure;
fig. 2 is a circuit schematic diagram of a charging voltage measurement circuit according to an embodiment of the present disclosure;
FIG. 3 is a circuit diagram of an external reference voltage measurement circuit according to an embodiment of the present disclosure;
fig. 4 is a circuit schematic diagram of a charging current measurement circuit according to an embodiment of the present disclosure.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly described below with reference to the accompanying drawings and the embodiments or the description in the prior art, it is obvious that the following description of the structure of the drawings is only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts. It should be noted that the description of the embodiments is provided to help understanding of the present invention, and the present invention is not limited thereto.
The embodiment is as follows:
as shown in fig. 1, a first aspect of the present embodiment provides a charging power measuring device for a charging cable, which can be used to measure a charging power of the charging cable between a charging power source and a charging device, and the charging power measuring device for the charging cable includes an MCU processor, a charging voltage measuring circuit, a charging current measuring circuit, an external reference voltage measuring circuit, and an external reference voltage generator. The MCU processor is respectively and electrically connected with the charging voltage measuring circuit, the charging current measuring circuit and the external reference voltage measuring circuit, the charging current measuring circuit is respectively and electrically connected with the charging power supply and the external reference voltage generator, and the charging power supply is respectively and electrically connected with the charging voltage measuring circuit and the external reference voltage generator.
The charging voltage measuring circuit is used for sampling the voltage of the charging power supply, obtaining a first sampling voltage of the charging power supply and uploading the first sampling voltage to the MCU processor. The external reference voltage measuring circuit is used for sampling the voltage of the external reference voltage generator to obtain a second sampling voltage of the external reference voltage generator and uploading the second sampling voltage to the MCU processor. And the charging current measuring circuit is used for sampling the voltage of the external reference voltage measuring circuit to obtain a third sampling voltage of the external reference voltage measuring circuit and uploading the third sampling voltage to the MCU processor. The MCU processor is used for determining the charging voltage of the charging power supply based on an internal reference voltage in the processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-to-digital converter (ADC) in the processor, a first digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the ADC, and a resistance value of a divider resistor used for voltage division in the charging voltage measuring circuit; determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a second digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through an analog-digital converter and a resistance value of a divider resistor for dividing the voltage in the external reference voltage measuring circuit; determining the charging current of the charging power supply based on the third digital voltage value obtained by converting the internal reference voltage, the first digital voltage value, the third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through the analog-digital converter, the resistance value of a divider resistor used for voltage division in the charging current measuring circuit, the reference voltage of the external reference voltage generator and the resistance value of a current detection resistor in the charging current measuring circuit; and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
Referring to fig. 2, the charging voltage measuring circuit includes a first resistor R4, a second resistor R8, a third resistor R7, and a first capacitor C6, one end of the first resistor R4 is connected to the charging power supply, the other end of the first resistor R4 is connected to one end of the second resistor R8, the other end of the second resistor R8 is grounded, one end of the third resistor R7 is connected between the first resistor R4 and the second resistor R8, the other end of the third resistor R7 is connected to the MCU processor, one end of the first capacitor C6 is grounded, and the other end of the first capacitor C6 is connected between the third resistor (R7) and the MCU processor. The first resistor R4 and the second resistor R8 are voltage dividing resistors for dividing voltage in the charging voltage measuring circuit.
Referring to fig. 3, the external reference voltage measuring circuit includes a fourth resistor R12, a fifth resistor R13, a sixth resistor R14, and a second capacitor C7, one end of the fourth resistor R12 is connected to the MCU processor, the other end of the fourth resistor R12 is connected to one end of the fifth resistor R13, the other end of the fifth resistor R13 is grounded, one end of the sixth resistor R14 is connected between the fourth resistor R12 and the fifth resistor R13, the other end of the sixth resistor R14 is connected to the external reference voltage generator, one end of the second capacitor C7 is connected between the sixth resistor R14 and the external reference voltage generator, and the other end of the second capacitor C7 is grounded. The fourth resistor R12 and the fifth resistor R13 are voltage dividing resistors for voltage division in the external reference voltage measuring circuit.
Referring to fig. 4, the charging current measuring circuit includes a seventh resistor R6, an eighth resistor R9, a ninth resistor R10, a tenth resistor R11, and a third capacitor C4, wherein one end of the ninth resistor R10 is connected to the external reference voltage measuring circuit, the other end of the ninth resistor R10 is connected to one end of the tenth resistor R11, the other end of the tenth resistor R11 is respectively connected to the MCU processor, one end of the eighth resistor R9, and ground, the other end of the eighth resistor R9 is grounded, one end of the seventh resistor R6 is connected between the ninth resistor R10 and the tenth resistor R11, the other end of the seventh resistor R6 is connected to the MCU processor, one end of the third capacitor C4 is connected between the ninth resistor R10 and the MCU processor, and the other end of the third capacitor C4 is grounded. The ninth resistor R10 and the tenth resistor R11 are voltage dividing resistors used for voltage division in the charging current measuring circuit, and the eighth resistor R9 is a current detecting resistor in the charging current measuring circuit.
In this embodiment, the MCU processor may be configured to determine the charging voltage of the charging power supply based on an internal reference voltage inside the processor, a first digital voltage value obtained by converting the internal reference voltage by an analog-to-digital converter inside the processor, a first digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measurement circuit by the analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the charging voltage measurement circuit.
Specifically, an analog-digital converter is arranged in the MCU processor, a reference voltage in the MCU processor is converted by the analog-digital converter to obtain a first digital voltage value, the charging voltage measuring circuit samples the voltage of the charging power supply, the first sampled voltage of the charging power supply is obtained and uploaded to the MCU processor, and the MCU processor can pass throughAnd the internal analog-digital converter converts the first sampling voltage into a corresponding digital voltage value to obtain a second digital voltage value. A first sampled voltage of the charging power supply is then calculated based on the internal reference voltage, the first digital voltage value, and the second digital voltage value. Example internal reference voltage is V 1.2 The first digital voltage value is DV 1.2 If the second digital voltage value DVbus and the first sampling voltage of the charging power supply is Vbus, V can be obtained 1.2 /DV 1.2 = Vbus/DVbus, so that a first sampling voltage Vbus = (V) of the charging source can be calculated 1.2 /DV 1.2 )*DVbus。
The voltage dividing resistors used for voltage division in the charging voltage measurement circuit are a first resistor R4 and a second resistor R8, the first resistor R4 and the second resistor R8 are high-precision resistors, for example, the resistance value of the first resistor R4 is R4, and the resistance value of the second resistor R8 is R8, then the charging voltage Vup _ Vbus of the charging power supply can be calculated according to the voltage dividing principle, and the charging voltage of the charging power supply can be represented as Vup _ Vbus = Vbus (1 + R4/R8).
In the embodiment of the application, the voltage of the charging power supply can be 5-48V. It is understood that in other embodiments, the voltage of the charging power source may have other values.
The MCU processor can be used for determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through the analog-digital converter and a resistance value of a divider resistor used for voltage division in the external reference voltage measuring circuit.
Specifically, the external reference voltage measuring circuit samples the voltage of the external reference voltage generator to obtain a second sampling voltage of the external reference voltage generator and uploads the second sampling voltage to the MCU processor, and the MCU processor can convert the second sampling voltage into a corresponding digital voltage value through the internal analog-digital converter to obtain a third digital voltage value. A second sampled voltage of the external reference voltage generator is then calculated based on the internal reference voltage, the first digital voltage value, and the third digital voltage value. Examples of such applications areThe third digital voltage is DVref, the second sampling voltage of the external reference voltage generator is Vref, and then V is obtained 1.2 /DV 1.2 = Vref/DVref, so that a second sampling voltage Vref = (V) of the external reference voltage generator can be calculated 1.2 /DV 1.2 )*DVref。
The voltage dividing resistors for voltage division in the external reference voltage measuring circuit are respectively a fourth resistor R12 and a fifth resistor R13, the fourth resistor R12 and the fifth resistor R13 are high-precision resistors, and for example, the resistance value of the fourth resistor R12 is R12, and the resistance value of the fifth resistor R13 is R13, the reference voltage VDD of the external reference voltage generator can be calculated according to the voltage dividing principle, and the reference voltage VDD of the external reference voltage generator can be expressed as VDD = Vref (1 × R12/R13).
By introducing the external reference voltage measuring circuit, the reference voltage of the external reference voltage generator is measured by the internal reference voltage of the MCU processor, so that the precision of the subsequently measured charging current is irrelevant to the external reference voltage measuring circuit and is relevant to the precision of the internal reference voltage of the MCU processor, and the precision of the internal reference voltage of the MCU processor is higher than that of the external reference voltage measuring circuit, so that the precision of the charging current measured in the subsequent process can be greatly improved.
The MCU processor can also be used for determining the charging current of the charging power supply based on a fourth digital voltage value obtained by converting an internal reference voltage, a first digital voltage value, a third sampling voltage of an external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a divider resistor used for voltage division in the charging current measuring circuit, the reference voltage of the external reference voltage generator and the resistance value of a current detection resistor in the charging current measuring circuit.
Specifically, after the charging current measuring circuit samples the voltage of the external reference voltage measuring circuit to obtain a third sampling voltage of the external reference voltage measuring circuit and uploads the third sampling voltage to the MCU processor, the MCU processor can convert the third sampling voltage of the external reference voltage measuring circuit into a corresponding digital voltage value through the internal analog-to-digital converter to obtain a third sampling voltage valueFour digital voltage values. A third sampled voltage of the external reference voltage measurement circuit is then calculated based on the internal reference voltage, the first digital voltage value, and the fourth digital voltage value. For example, if the fourth digital voltage value is DVsense and the third sampling voltage of the external reference voltage measuring circuit is Vsense, V can be obtained 1.2 /DV 1.2 And the third sampling voltage Vsense = (V) of the external reference voltage measuring circuit can be calculated by using the voltage Vsense/DVsense 1.2 /DV 1.2 )*DVsense。
The resistance values of the voltage dividing resistors for voltage division in the charging current measuring circuit are a ninth resistor R10 and a tenth resistor R11, the eighth resistor R9 is a current detecting resistor in the charging current measuring circuit, and the eighth resistor R9, the ninth resistor R10 and the tenth resistor R11 are high-precision resistors in the same way. For example, if the resistance value of the eighth resistor R9 is R9, the resistance value of the ninth resistor R10 is R10, and the resistance value of the tenth resistor R11 is R11, the voltage difference Vcharge = ((R10 + R11) × Vsense-R11 × VDD)/R10 between both ends of the current detection resistor (the eighth resistor R9) can be calculated.
After calculating the voltage difference Vcharge across the current detection resistor, the MCU processor may calculate the charging current icharge of the charging power supply based on the voltage difference Vcharge across the current detection resistor and the resistance of the current detection resistor, where the charging current icharge = Vcharge/r9.
Finally, the MCU processor may determine a charging power Pcharge of a charging cable between the charging power source and the charging device based on a charging voltage Vup _ bus of the charging power source and a charging current icharge of the charging power source, which may be denoted Pcharge = Vup _ bus icharge.
In one or more embodiments, the charging power measurement apparatus for a charging cable may further include a power display circuit electrically connected to the MCU processor for displaying the charging power of the charging cable between the charging power source and the charging device. The power display circuit may be an existing display circuit, and is not specifically described in the embodiments of the present application.
In addition, a plurality of analog-to-digital converters may be provided inside the MCU processor, and each analog-to-digital converter may be configured to perform digital conversion on different voltages. The MCU processor may have various implementation manners, for example, but not limited to, an OB38a08A1W10-C type single chip microcomputer or an OB38a04T1W080P type single chip microcomputer may be adopted, and the embodiment of the present application is not particularly limited.
To sum up, the charging power measuring apparatus for a charging cable provided in the embodiment of the present application is configured with an MCU processor, a charging voltage measuring circuit, a charging current measuring circuit, an external reference voltage measuring circuit, and an external reference voltage generator, where the MCU processor is electrically connected to the charging voltage measuring circuit, the charging current measuring circuit, and the external reference voltage measuring circuit, the charging current measuring circuit is electrically connected to a charging power supply and the external reference voltage generator, and the charging power supply is electrically connected to the charging voltage measuring circuit and the external reference voltage generator, respectively, where the MCU processor is configured to determine a charging voltage of the charging power supply based on an internal reference voltage inside the processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-to-digital converter inside the processor, a second digital voltage value obtained by converting a first sampled voltage of the charging power supply sampled by the charging voltage measuring circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor in the charging voltage measuring circuit; determining the reference voltage of the external reference voltage generator based on the third digital voltage value obtained by converting the internal reference voltage, the first digital voltage value, the second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through the analog-digital converter and the resistance value of a divider resistor for dividing the voltage in the external reference voltage measuring circuit; determining the charging current of the charging power supply based on a fourth digital voltage value obtained by converting an internal reference voltage, a first digital voltage value, a third sampling voltage of an external reference voltage measuring circuit sampled by a charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor used for voltage division in the charging current measuring circuit, a reference voltage of an external reference voltage generator and a resistance value of a current detecting resistor in the charging current measuring circuit; and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply. Therefore, when the charging power of the charging cable between the charging power supply and the charging equipment is measured, the voltage of the external reference voltage measuring circuit is measured by using the internal reference voltage of the MCU processor, so that the precision of the charging current is irrelevant to the external reference voltage of the external reference voltage generator and is relevant to the precision of the internal reference voltage of the MCU processor, and the precision of the internal reference voltage of the MCU processor is obviously higher than the external reference voltage of the external reference voltage generator, thereby improving the measurement precision of the charging current and further more accurately measuring the charging power of the charging cable between the charging power supply and the charging equipment. Meanwhile, the charging power measuring device for the charging cable provided by the embodiment of the application only needs to introduce the external reference voltage measuring circuit, the size of the charging power measuring device is not excessively increased, the charging power measuring device is particularly suitable for the charging cable or other scenes with limited design space, the measurement accuracy of the charging power can be improved with relatively low production and design cost under the condition of limited design space, and the charging power measuring device is convenient to popularize and apply practically.
In a second aspect, an embodiment of the present application provides a charging power measurement method, where the charging power measurement method is applicable to the MCU processor of the charging power measurement apparatus for a charging cable described in the first aspect, and the charging power measurement method includes:
determining the charging voltage of the charging power supply based on an internal reference voltage in a processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter (ADC) in the processor, a first digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the ADC, and a resistance value of a voltage dividing resistor for dividing the voltage in the charging voltage measuring circuit;
determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a second digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through an analog-digital converter, and a resistance value of a voltage dividing resistor for dividing the voltage in the external reference voltage measuring circuit;
determining a charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor for dividing voltage in the charging current measuring circuit, a reference voltage of the external reference voltage generator, and a resistance value of a current detecting resistor in the charging current measuring circuit;
and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
For the working process, the working details, and the technical effects of the method provided in the second aspect of this embodiment, reference may be made to the first aspect of this embodiment, which is not described herein again.
Finally, it should be noted that: the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A charging power measurement device for a charging cable, comprising: the charging device comprises an MCU processor, a charging voltage measuring circuit, a charging current measuring circuit, an external reference voltage measuring circuit and an external reference voltage generator, wherein the MCU processor is respectively and electrically connected with the charging voltage measuring circuit, the charging current measuring circuit and the external reference voltage measuring circuit;
the MCU processor is used for determining the charging voltage of the charging power supply based on an internal reference voltage in the processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter in the processor, a second digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the analog-digital converter, and a resistance value of a divider resistor used for voltage division in the charging voltage measuring circuit;
determining a reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the external reference voltage measuring circuit;
determining a charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a fourth digital voltage value obtained by converting a third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor for dividing voltage in the charging current measuring circuit, a reference voltage of the external reference voltage generator, and a resistance value of a current detecting resistor in the charging current measuring circuit; and
and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
2. The charging power measurement device for the charging cable according to claim 1, wherein the charging voltage measurement circuit comprises a first resistor (R4), a second resistor (R8), a third resistor (R7) and a first capacitor (C6), one end of the first resistor (R4) is connected with the charging power supply, the other end of the first resistor (R4) is connected with one end of the second resistor (R8), the other end of the second resistor (R8) is grounded, one end of the third resistor (R7) is connected between the first resistor (R4) and the second resistor (R8), the other end of the third resistor (R7) is connected with the MCU processor, one end of the first capacitor (C6) is grounded, and the other end of the first capacitor (C6) is connected between the third resistor (R7) and the MCU processor;
the first resistor (R4) and the second resistor (R8) are voltage dividing resistors used for voltage division in the charging voltage measuring circuit.
3. The charging power measurement device for the charging cable according to claim 1, wherein the external reference voltage measurement circuit includes a fourth resistor (R12), a fifth resistor (R13), a sixth resistor (R14), and a second capacitor (C7), one end of the fourth resistor (R12) is connected to the MCU processor, the other end of the fourth resistor (R12) is connected to one end of the fifth resistor (R13), the other end of the fifth resistor (R13) is grounded, one end of the sixth resistor (R14) is connected between the fourth resistor (R12) and the fifth resistor (R13), the other end of the sixth resistor (R14) is connected to the external reference voltage generator, one end of the second capacitor (C7) is connected between the sixth resistor (R14) and the external reference voltage generator, and the other end of the second capacitor (C7) is grounded;
the fourth resistor (R12) and the fifth resistor (R13) are voltage dividing resistors for voltage division in the external reference voltage measuring circuit.
4. The charging power measurement device for the charging cable according to claim 1, wherein the charging current measurement circuit includes a seventh resistor (R6), an eighth resistor (R9), a ninth resistor (R10), a tenth resistor (R11), and a third capacitor (C4), one end of the ninth resistor (R10) is connected to the external reference voltage measurement circuit, the other end of the ninth resistor (R10) is connected to one end of the tenth resistor (R11), the other end of the tenth resistor (R11) is respectively connected to the MCU processor, one end of the eighth resistor (R9), and ground, the other end of the eighth resistor (R9) is grounded, one end of the seventh resistor (R6) is connected between the ninth resistor (R10) and the tenth resistor (R11), the other end of the seventh resistor (R6) is connected to the MCU processor, one end of the third capacitor (C4) is connected between the ninth resistor (R10) and the MCU processor, and the other end of the third capacitor (C4) is grounded;
the ninth resistor (R10) and the tenth resistor (R11) are voltage dividing resistors for voltage division in the charging current measuring circuit, and the eighth resistor (R9) is a current detecting resistor in the charging current measuring circuit.
5. The charging power measurement device for the charging cable of claim 1, further comprising a power display circuit electrically connected with the MCU processor.
6. The charging power measurement device for the charging cable according to claim 1, wherein the MCU processor is specifically configured to, when determining the charging voltage of the charging power supply based on an internal reference voltage inside the processor, a first digital voltage value obtained by converting the internal reference voltage by an analog-to-digital converter inside the processor, a second digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measurement circuit by an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the charging voltage measurement circuit:
calculating a first sampling voltage of the charging power supply based on the internal reference voltage, the first digital voltage value, and the second digital voltage value;
and calculating the charging voltage of the charging power supply based on the first sampling voltage of the charging power supply and the resistance value of a voltage dividing resistor used for voltage division in the charging voltage measuring circuit.
7. The charging power measurement device for the charging cable according to claim 1, wherein the MCU processor is specifically configured to, when determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a second sampled voltage of the external reference voltage generator sampled by the external reference voltage measurement circuit through an analog-to-digital converter, and a resistance value of a voltage dividing resistor for voltage division in the external reference voltage measurement circuit:
calculating a second sampling voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, and the third digital voltage value;
and calculating the reference voltage of the external reference voltage generator based on the second sampling voltage of the external reference voltage generator and the resistance value of a voltage dividing resistor for dividing the voltage in the external reference voltage measuring circuit.
8. The charging power measurement device for the charging cable according to claim 1, wherein the MCU processor is specifically configured to, when determining the charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a fourth digital voltage value obtained by converting a third sampled voltage of the external reference voltage measurement circuit sampled by the charging current measurement circuit by an analog-to-digital converter, a resistance value of a voltage dividing resistor for voltage division in the charging current measurement circuit, a reference voltage of an external reference voltage generator, and a resistance value of a current detection resistor in the charging current measurement circuit:
calculating a third sampling voltage of the external reference voltage measurement circuit based on the internal reference voltage, the first digital voltage value, and the fourth digital voltage value;
calculating a voltage difference between both ends of the current detection resistor based on a third sampling voltage of the external reference voltage measurement circuit, a resistance value of a voltage division resistor for voltage division in the charging current measurement circuit, and a reference voltage of the external reference voltage generator;
and calculating the charging current of the charging power supply based on the voltage difference between the two ends of the current detection resistor and the resistance value of the current detection resistor.
9. The charging power measurement device for the charging cable according to claim 1, wherein a voltage of the charging power supply is 5-48V.
10. A charging power measurement method applied to the MCU processor of the charging power measurement apparatus for a charging cable of any one of claims 1 to 9, the method comprising:
determining the charging voltage of the charging power supply based on an internal reference voltage in a processor, a first digital voltage value obtained by converting the internal reference voltage through an analog-digital converter (ADC) in the processor, a first digital voltage value obtained by converting a first sampling voltage of the charging power supply sampled by the charging voltage measuring circuit through the ADC, and a resistance value of a divider resistor for voltage division in the charging voltage measuring circuit;
determining the reference voltage of the external reference voltage generator based on the internal reference voltage, the first digital voltage value, a second digital voltage value obtained by converting a second sampling voltage of the external reference voltage generator sampled by the external reference voltage measuring circuit through an analog-digital converter, and a resistance value of a voltage dividing resistor for dividing the voltage in the external reference voltage measuring circuit;
determining a charging current of the charging power supply based on the internal reference voltage, the first digital voltage value, a third digital voltage value obtained by converting a third sampling voltage of the external reference voltage measuring circuit sampled by the charging current measuring circuit through an analog-digital converter, a resistance value of a voltage dividing resistor for dividing voltage in the charging current measuring circuit, a reference voltage of the external reference voltage generator, and a resistance value of a current detecting resistor in the charging current measuring circuit;
and determining the charging power of a charging cable between the charging power supply and the charging equipment based on the charging voltage of the charging power supply and the charging current of the charging power supply.
CN202211091884.7A 2022-09-07 2022-09-07 Charging power measuring device and method for charging cable Pending CN115656622A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211091884.7A CN115656622A (en) 2022-09-07 2022-09-07 Charging power measuring device and method for charging cable

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211091884.7A CN115656622A (en) 2022-09-07 2022-09-07 Charging power measuring device and method for charging cable

Publications (1)

Publication Number Publication Date
CN115656622A true CN115656622A (en) 2023-01-31

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