CN117849438A - Heavy current sampling method, device and storage medium - Google Patents
Heavy current sampling method, device and storage medium Download PDFInfo
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Abstract
The invention discloses a large-current sampling method, a large-current sampling device and a storage medium. The high-current sampling method of the embodiment of the invention introduces the idea of temperature compensation, and provides a mode for determining the comparison example coefficient and the offset coefficient, thereby ensuring the accuracy of the actual working current finally detected and calculated and eliminating the problem of error of the sampling resistor caused by temperature change.
Description
Technical Field
The invention relates to the field of intelligent meters, in particular to a high-current sampling method, a device and a storage medium.
Background
The intelligent instrument devices such as a power supply and a battery simulator generally use a resistor with different mΩ to hundreds mΩ as a sampling resistor, and after the resistor voltage is collected, the current flowing through the resistor is calculated by using ohm law, but as the current (particularly when the current is larger) flows through the resistor, the resistor generates power consumption, the temperature of the resistor is increased along with the power consumption, and the resistance value of the resistor is inevitably changed after the temperature is increased, so that the calculated theoretical value and the actual value of the current deviate, and the precision range is exceeded when the temperature is serious, so that the product cannot be normally used.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a high-current sampling method, which solves the problem that errors occur due to temperature change when detecting the current of the sampling resistor.
The invention also provides a high-current sampling device and a computer readable storage medium.
The high-current sampling method according to the embodiment of the first aspect of the invention is applied to a sampling system, the sampling system comprises a voltage acquisition unit and a temperature acquisition unit, the voltage acquisition unit is used for acquiring the detection voltage of the sampling resistor, the temperature acquisition unit is used for acquiring the resistance temperature of the sampling resistor, and the sampling resistor is connected in series with a work load and a work power supply;
the high-current sampling method comprises the following steps:
acquiring the resistance temperature acquired by the temperature acquisition unit;
acquiring the detection voltage acquired by the voltage acquisition unit;
obtaining theoretical detection current according to the detection voltage and the theoretical resistance of the sampling resistor;
obtaining a temperature deviation correction current according to the theoretical detection current, the resistance temperature and a pre-obtained relation between the resistance temperature and the current deviation;
Obtaining the actual working current flowing through the working load according to the temperature deviation correction current and the theoretical detection current;
wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply to output a first actual current, and adjusting the ambient temperature to a first ambient temperature so that the resistance temperature of the sampling resistor reaches a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor;
determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor reaches a second calibration temperature, and acquiring a second calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor;
determining a second temperature compensation current according to the second actual current and the second calibration current;
Determining a proportionality coefficient and an offset coefficient of a pre-obtained basic relation according to the first calibration temperature, the first calibration current, the first temperature compensation current, the second calibration temperature, the second calibration current and the second temperature compensation current, wherein the basic relation represents a positive correlation relation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature;
and carrying the proportionality coefficient and the offset coefficient into the basic relation to obtain the relation between the resistance temperature and the current deviation.
The high-current sampling method provided by the embodiment of the invention has at least the following beneficial effects:
the corresponding relation between the temperature change and the current change can be known by acquiring the relation between the resistance temperature and the current deviation in advance, and the actual working current can be obtained by acquiring the resistance temperature of the sampling resistor and acquiring the theoretical detection current, so that the temperature deviation correction current can be obtained and the temperature deviation correction current can be used for finishing correction. The high-current sampling method of the embodiment of the invention introduces the idea of temperature compensation, and provides a mode for determining the comparison example coefficient and the offset coefficient, thereby ensuring the accuracy of the actual working current finally detected and calculated and eliminating the problem of error of the sampling resistor caused by temperature change.
According to some embodiments of the invention, the adjusting the operating power supply to output the first actual current includes:
and adjusting the output current of the working power supply, and detecting the output current of the working power supply by using a current detection device until the working power supply outputs the first actual current.
According to some embodiments of the invention, the adjusting the operating power supply to output a second actual current includes:
and adjusting the output current of the working power supply, and detecting the output current of the working power supply by using a current detection device until the working power supply outputs the second actual current.
According to some embodiments of the invention, the theoretical detection current calculated according to 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detection current calculated according to 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current.
According to some embodiments of the invention, the first calibration temperature is 20% of a preset usage environment temperature high threshold of the sampling resistor, and the second calibration temperature is 80% of the preset usage environment temperature high threshold of the sampling resistor.
According to some embodiments of the invention, the resistance temperature versus current bias relationship is:
I T ＝I AD *T*{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}+{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}
*I AD *T1}，
wherein I is T Correcting current for said temperature deviation, I T1 Compensating the current for the first temperature, I T2 Compensating the current for the second temperature, I AD For the theoretical detection current, I AD1 For the first calibration current, I AD2 And for the first calibration current, T is the resistance temperature, T1 is the first calibration temperature, and T2 is the second calibration temperature.
The high-current sampling system according to the embodiment of the second aspect of the invention is applied to a sampling system, and comprises a voltage acquisition unit and a temperature acquisition unit, wherein the voltage acquisition unit is used for acquiring the detection voltage of the sampling resistor, the temperature acquisition unit is used for acquiring the resistance temperature of the sampling resistor, and the sampling resistor is connected in series with a work load and a work power supply;
the high-current sampling device includes:
the temperature acquisition module is used for acquiring the resistance temperature acquired by the temperature acquisition unit;
the voltage acquisition module is used for acquiring the detection voltage acquired by the voltage acquisition unit;
the theoretical current calculation module is used for obtaining theoretical detection current according to the detection voltage and the theoretical resistance of the sampling resistor;
The corrected current acquisition module is used for acquiring a temperature deviation corrected current according to the theoretical detected current, the resistance temperature and a pre-acquired relation between the resistance temperature and the current deviation;
the current output module is used for correcting the current and the theoretical detection current according to the temperature deviation to obtain the actual working current flowing through the working load;
wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply to output a first actual current, and adjusting the ambient temperature to a first ambient temperature so that the resistance temperature of the sampling resistor reaches a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor;
determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor reaches a second calibration temperature, and acquiring a second calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
Determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor;
determining a second temperature compensation current according to the second actual current and the second calibration current;
determining a proportionality coefficient and an offset coefficient of a pre-obtained basic relation according to the first calibration temperature, the first calibration current, the first temperature compensation current, the second calibration temperature, the second calibration current and the second temperature compensation current, wherein the basic relation represents a positive correlation relation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature;
and carrying the proportionality coefficient and the offset coefficient into the basic relation to obtain the relation between the resistance temperature and the current deviation.
The high-current sampling device provided by the embodiment of the invention has at least the following beneficial effects:
the corresponding relation between the temperature change and the current change can be known by acquiring the relation between the resistance temperature and the current deviation in advance, and the actual working current can be obtained by acquiring the resistance temperature of the sampling resistor and acquiring the theoretical detection current, so that the temperature deviation correction current can be obtained and the temperature deviation correction current can be used for finishing correction. The high-current sampling device provided by the embodiment of the invention introduces the idea of temperature compensation, and provides a mode for determining the comparison example coefficient and the offset coefficient, so that the accuracy of the actual working current finally detected and calculated can be ensured, and the problem that the sampling resistor generates errors due to temperature change is solved.
According to some embodiments of the invention, the theoretical detection current calculated according to 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detection current calculated according to 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current.
According to some embodiments of the invention, the first calibration temperature is 20% of a preset usage environment temperature high threshold of the sampling resistor, and the second calibration temperature is 80% of the preset usage environment temperature high threshold of the sampling resistor.
According to an embodiment of the third aspect of the present invention, there is stored computer-executable instructions for performing the high current sampling method as described in the embodiment of the first aspect. Since the computer-readable storage medium adopts all the technical solutions of the high-current sampling method of the above embodiments, it has at least all the advantageous effects brought by the technical solutions of the above embodiments.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
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The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic diagram of a sampling system setup according to an embodiment of the present invention;
FIG. 2 is a flow chart of a high current sampling method according to an embodiment of the present invention;
FIG. 3 is a flowchart illustrating a method for obtaining a relationship between resistance temperature and current deviation according to an embodiment of the present invention.
Reference numerals:
sampling system 100, work load 200, work power supply 300, sampling resistor 400.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
In the description of the present invention, the description of first, second, etc. is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, it should be understood that the direction or positional relationship indicated with respect to the description of the orientation, such as up, down, etc., is based on the direction or positional relationship shown in the drawings, is merely for convenience of describing the present invention and simplifying the description, and does not indicate or imply that the apparatus or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be determined reasonably by a person skilled in the art in combination with the specific content of the technical solution.
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which it is apparent that the embodiments described below are some, but not all embodiments of the invention.
Referring to fig. 2, fig. 2 is a flowchart of a high current sampling method according to an embodiment of the present invention, including, but not limited to, the following steps:
acquiring the resistance temperature acquired by the temperature acquisition unit;
acquiring detection voltage acquired by a voltage acquisition unit;
Obtaining a theoretical detection current according to the detection voltage and the theoretical resistance of the sampling resistor 400;
obtaining a temperature deviation correction current according to theoretical detection current, resistance temperature and a pre-obtained relation between resistance temperature and current deviation;
obtaining an actual working current flowing through the working load 200 according to the temperature deviation correction current and the theoretical detection current;
wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply 300 to output a first actual current, and adjusting the ambient temperature to the first ambient temperature so as to enable the resistance temperature of the sampling resistor 400 to reach a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor 400 acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor 400;
determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply 300 to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor 400 reaches a second calibration temperature, thereby obtaining a second calibration voltage of the sampling resistor 400 acquired by the voltage acquisition unit;
determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor 400;
Determining a second temperature compensation current according to the second actual current and the second calibration current;
determining a proportionality coefficient and an offset coefficient of a basic relation obtained in advance according to a first calibration temperature, a first calibration current, a first temperature compensation current, a second calibration temperature, a second calibration current and a second temperature compensation current, wherein the basic relation represents a positive correlation between a temperature deviation correction current and a product of a theoretical detection current and a resistance temperature;
and bringing the proportionality coefficient and the offset coefficient into a basic relation to obtain a relation between the resistance temperature and the current deviation.
Referring to fig. 1, the working power supply 300, the working load 200, and the sampling resistor 400 are connected in series, and thus the current flowing through the working load 200 can be converted into the current flowing through the sampling resistor 400. The sampling system 100 includes a voltage acquisition unit, a temperature acquisition unit, and a data processing unit; the voltage sampling unit can collect the detection voltages at two ends of the sampling resistor 400, and calculate a theoretical detection current by using the detection voltages and the theoretical resistance of the sampling resistor 400, wherein the theoretical detection current does not consider the influence of temperature on the resistance of the sampling resistor 400, so that a certain error exists; the temperature acquisition unit can acquire the resistance temperature of the sampling resistor 400, so that the current correction can be conveniently performed by using the resistance temperature later. In some embodiments, the temperature acquisition unit may employ a chip thermistor, and the temperature of the sampling resistor 400 may be acquired by attaching the chip thermistor to the sampling resistor 400.
Based on the above system configuration, embodiments of the present invention are described.
In the embodiment of the present invention, after the resistance temperature and the detection voltage of the sampling resistor 400 are detected, the theoretical detection current is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400, so that the temperature deviation correction current can be obtained by using the theoretical detection current and the resistance temperature based on the relation between the resistance temperature and the current deviation, and the final actual working current flowing through the working load 200 is determined by using the temperature deviation correction current and the theoretical detection current. The obtaining of the relation between the resistance temperature and the current deviation is a key that the temperature deviation correction current can be obtained in the embodiment of the invention, and the process of obtaining the relation between the resistance temperature and the current deviation is further described herein, which is specifically as follows.
Referring to fig. 3, assume that the actual current flowing through sampling resistor 400 is I S Then I S ＝I AD +I T Wherein I AD To theoretically detect current, I T Correcting the current for the temperature deviation;
by actual measurement, the positive correlation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature can be determined as a basic relational expression: i T ＝I AD * T+k+b, where T is the resistance temperature, K is the scaling factor, and B is the offset factor. The resistance temperature T in the basic relation can be measured, I AD Can be obtained by calculating the detection voltage acquired by the voltage acquisition unit, I T Can be passed through I S And I AD Calculated, wherein I S Can be used forThe current flowing through the sampling resistor 400 is directly detected by an external current detection device.
Considering that two coefficients to be determined exist in the basic relational expression, the sampling resistor 400 can be adjusted to two different working environments to obtain two groups of different relational expressions, and then the proportional coefficient and the offset coefficient can be determined by analyzing the two relational expressions; in the embodiment of the invention, the first working environment is set as follows: by adjusting the operating power supply 300 to output the first actual current and adjusting the ambient temperature to the first ambient temperature so that the resistance temperature of the sampling resistor 400 reaches the first calibration temperature, the second operating environment is set as follows: the second actual current is output by adjusting the operating power supply 300, and the ambient temperature is adjusted to the second ambient temperature, so that the resistance temperature of the sampling resistor 400 reaches the second calibration temperature.
Under the first working environment, the detection voltage acquired by the voltage acquisition unit is acquired, and the first calibration current I is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400 AD1 Meanwhile, an external current detection device is utilized to detect the first actual current, and then the first actual current and the first calibration current can be utilized to calculate a first temperature compensation current I T1 The first calibration temperature T1 may be directly measured by the temperature detection unit, so that only two undetermined coefficients of the scaling coefficient and the offset coefficient may exist in the basic relational expression, thereby obtaining a first relational expression: i T1 ＝I AD1 *T1*K+B。
Under the second working environment, the detection voltage acquired by the voltage acquisition unit is acquired, and the second calibration current I is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400 AD2 Meanwhile, the external current detection device is utilized to detect the second actual current, and the second temperature compensation current I can be calculated by utilizing the second actual current and the second calibration current T2 The second calibration temperature T2 may be directly measured by the temperature detection unit, so that only two undetermined coefficients of the scaling coefficient and the offset coefficient may exist in the basic relational expression, thereby obtaining a second relational expression: i T2 ＝I AD2 *T2*K+B。
By simultaneously solving the first relation and the second relation, a scaling factor and an offset factor can be resolved, wherein the scaling factor is as follows:
{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}，
The offset coefficient is:
{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}*I AD *T1}，
the scaling factor and the offset factor are brought back into the basic relation, so that a final relation of resistance temperature and current deviation can be obtained. After the relation between the resistance temperature and the current deviation is obtained, the temperature deviation correction current can be quickly obtained after the resistance temperature and the theoretical detection current are obtained.
According to the high-current sampling method, the corresponding relation between the temperature change and the current change can be known by acquiring the relation between the resistance temperature and the current deviation in advance, and the temperature deviation correction current can be obtained by acquiring the resistance temperature of the sampling resistor 400 and acquiring the theoretical detection current, so that the correction of the temperature deviation correction current can be completed by utilizing the temperature deviation correction current, and the actual working current is obtained. The high-current sampling method of the embodiment of the invention introduces the idea of temperature compensation and provides a mode for determining the comparison example coefficient and the offset coefficient, thereby ensuring the accuracy of the actual working current finally detected and calculated and eliminating the problem of error of the sampling resistor 400 caused by temperature change.
In some embodiments, adjusting the operating power supply 300 to output the first actual current includes:
The output current of the working power supply 300 is adjusted while detecting the output current of the working power supply 300 by the current detection device until the working power supply 300 outputs the first actual current.
The working power supply 300 cannot detect the current flowing through the sampling resistor 400, so that in order to ensure that the working power supply 300 can output the first actual current, an external current detection device can be utilized to detect the output current of the working power supply 300 in real time until the output current is the first actual current.
In some embodiments, adjusting the operating power supply 300 to output the second actual current includes:
the output current of the working power supply 300 is adjusted while detecting the output current of the working power supply 300 by the current detection device until the working power supply 300 outputs the second actual current.
The working power supply 300 cannot detect the current flowing through the sampling resistor 400, so that in order to ensure that the working power supply 300 can output the second actual current, an external current detection device can be utilized to detect the output current of the working power supply 300 in real time until the output current is the second actual current.
In some embodiments, the theoretical detected current calculated from 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detected current calculated from 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current. The first calibration temperature is 20% of the high threshold of the preset usage environment temperature of the sampling resistor 400, and the second calibration temperature is 80% of the high threshold of the preset usage environment temperature of the sampling resistor 400.
The first actual current and the second actual current are set according to the detection range of the voltage acquisition unit, and it can be understood that a corresponding relationship exists between the detection voltage detected by the voltage acquisition unit and the theoretical detection current calculated by further combining ohm's law, so that the full range of the current can actually correspond to the full range of the voltage, and 20% and 80% of the full range are selected as two measuring points in the embodiment, and the accuracy of the detection can be effectively ensured.
It should be noted that, the temperature of the sampling resistor 400 will change due to the change of the current, and the greater the current, the higher the temperature, and the two measurement points are determined in consideration of the temperature fluctuation range (that is, the upper limit of the temperature fluctuation range may be determined as the preset usage environment temperature high threshold) of the sampling resistor 400 in actual usage, where 20% and 80% are selected as the two measurement points, and correspond to the first actual current and the second actual current, so as to finally obtain two working environments.
In some embodiments, the resistance temperature versus current bias relationship is:
I T ＝I AD *T*{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}+{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}
*I AD *T1}，
wherein I is T Correcting current for temperature deviation, I T1 For the first temperature compensation current, I T2 For the second temperature compensation current, I AD To theoretically detect current, I AD1 For a first calibration current, I AD2 The temperature sensor is characterized in that the temperature sensor is used for measuring a first calibration current, T is a resistance temperature, T1 is a first calibration temperature, and T2 is a second calibration temperature.
And the obtained proportional coefficient and the deviation coefficient are brought into a basic relational expression, so that a relational expression of resistance temperature and current deviation can be obtained, and the theoretical detection current and the resistance temperature can be obtained through measurement and calculation by utilizing the relational expression of resistance temperature and current deviation, so that the temperature deviation correction current can be quickly obtained.
The embodiment of the invention also provides a high-current sampling device which comprises a temperature acquisition module, a voltage acquisition module, a theoretical current calculation module, a correction current acquisition module and a current output module;
the temperature acquisition module is used for acquiring the resistance temperature acquired by the temperature acquisition unit;
the voltage acquisition module is used for acquiring the detection voltage acquired by the voltage acquisition unit;
the theoretical current calculation module is configured to obtain a theoretical detection current according to the detection voltage and a theoretical resistance of the sampling resistor 400;
the corrected current acquisition module is used for acquiring a temperature deviation corrected current according to the theoretical detected current, the resistance temperature and a pre-acquired relation between the resistance temperature and the current deviation;
The current output module is used for correcting the current and the theoretical detection current according to the temperature deviation to obtain the actual working current flowing through the working load 200;
wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply 300 to output a first actual current, and adjusting the ambient temperature to the first ambient temperature so as to enable the resistance temperature of the sampling resistor 400 to reach a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor 400 acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor 400;
determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply 300 to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor 400 reaches a second calibration temperature, thereby obtaining a second calibration voltage of the sampling resistor 400 acquired by the voltage acquisition unit;
determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor 400;
determining a second temperature compensation current according to the second actual current and the second calibration current;
determining a proportionality coefficient and an offset coefficient of a basic relation obtained in advance according to a first calibration temperature, a first calibration current, a first temperature compensation current, a second calibration temperature, a second calibration current and a second temperature compensation current, wherein the basic relation represents a positive correlation between a temperature deviation correction current and a product of a theoretical detection current and a resistance temperature;
And bringing the proportionality coefficient and the offset coefficient into a basic relation to obtain a relation between the resistance temperature and the current deviation.
Referring to fig. 1, the working power supply 300, the working load 200, and the sampling resistor 400 are connected in series, and thus the current flowing through the working load 200 can be converted into the current flowing through the sampling resistor 400. The sampling system 100 includes a voltage acquisition unit, a temperature acquisition unit, and a data processing unit; the voltage sampling unit can collect the detection voltages at two ends of the sampling resistor 400, and calculate a theoretical detection current by using the detection voltages and the theoretical resistance of the sampling resistor 400, wherein the theoretical detection current does not consider the influence of temperature on the resistance of the sampling resistor 400, so that a certain error exists; the temperature acquisition unit can acquire the resistance temperature of the sampling resistor 400, so that the current correction can be conveniently performed by using the resistance temperature later. In some embodiments, the temperature acquisition unit may employ a chip thermistor, and the temperature of the sampling resistor 400 may be acquired by attaching the chip thermistor to the sampling resistor 400.
Based on the above system configuration, embodiments of the present invention are described.
In the embodiment of the present invention, after the resistance temperature and the detection voltage of the sampling resistor 400 are detected, the theoretical detection current is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400, so that the temperature deviation correction current can be obtained by using the theoretical detection current and the resistance temperature based on the relation between the resistance temperature and the current deviation, and the final actual working current flowing through the working load 200 is determined by using the temperature deviation correction current and the theoretical detection current. The obtaining of the relation between the resistance temperature and the current deviation is a key that the temperature deviation correction current can be obtained in the embodiment of the invention, and the process of obtaining the relation between the resistance temperature and the current deviation is further described herein. Specifically, the following is described.
Assume that the actual current flowing through sampling resistor 400 is I S Then I S ＝I AD +I T Wherein I AD To theoretically detect current, I T Correcting the current for the temperature deviation;
by actual measurement, the positive correlation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature can be determined as a basic relational expression: i T ＝I AD * T+k+b, where T is the resistance temperature, K is the scaling factor, and B is the offset factor. The resistance temperature T in the basic relation can be measured, I AD Can be obtained by calculating the detection voltage acquired by the voltage acquisition unit, I T Can be passed through I S And I AD Calculated, wherein I S Can be used forThe current flowing through the sampling resistor 400 is directly detected by an external current detection device.
Considering that two coefficients to be determined exist in the basic relational expression, the sampling resistor 400 can be adjusted to two different working environments to obtain two groups of different relational expressions, and then the proportional coefficient and the offset coefficient can be determined by analyzing the two relational expressions; in the embodiment of the invention, the first working environment is set as follows: by adjusting the operating power supply 300 to output the first actual current and adjusting the ambient temperature to the first ambient temperature so that the resistance temperature of the sampling resistor 400 reaches the first calibration temperature, the second operating environment is set as follows: the second actual current is output by adjusting the operating power supply 300, and the ambient temperature is adjusted to the second ambient temperature, so that the resistance temperature of the sampling resistor 400 reaches the second calibration temperature.
Under the first working environment, the detection voltage acquired by the voltage acquisition unit is acquired, and the first calibration current I is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400 AD1 Meanwhile, an external current detection device is utilized to detect the first actual current, and then the first actual current and the first calibration current can be utilized to calculate a first temperature compensation current I T1 The first calibration temperature T1 may be directly measured by the temperature detection unit, so that only two undetermined coefficients of the scaling coefficient and the offset coefficient may exist in the basic relational expression, thereby obtaining a first relational expression: i T1 ＝I AD1 *T1*K+B。
Under the second working environment, the detection voltage acquired by the voltage acquisition unit is acquired, and the second calibration current I is calculated by using the detection voltage and the theoretical resistance of the sampling resistor 400 AD2 Meanwhile, the external current detection device is utilized to detect the second actual current, and the second temperature compensation current I can be calculated by utilizing the second actual current and the second calibration current T2 The second calibration temperature T2 may be directly measured by the temperature detection unit, so that only two undetermined coefficients of the scaling coefficient and the offset coefficient may exist in the basic relational expression, thereby obtaining a second relational expression: i T2 ＝I AD2 *T2*K+B。
By simultaneously solving the first relation and the second relation, a scaling factor and an offset factor can be resolved, wherein the scaling factor is as follows:
{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}，
the offset coefficient is:
{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}*I AD *T1}，
the scaling factor and the offset factor are brought back into the basic relation, so that a final relation of resistance temperature and current deviation can be obtained. After the relation between the resistance temperature and the current deviation is obtained, the temperature deviation correction current can be quickly obtained after the resistance temperature and the theoretical detection current are obtained.
According to the high-current sampling device, the corresponding relation between the temperature change and the current change can be known by acquiring the relation between the resistance temperature and the current deviation in advance, and the temperature deviation correction current can be obtained by acquiring the resistance temperature of the sampling resistor 400 and acquiring the theoretical detection current, so that the correction of the temperature deviation correction current can be completed by utilizing the temperature deviation correction current, and the actual working current is obtained. The high-current sampling device of the embodiment of the invention introduces the idea of temperature compensation and provides a mode for determining the comparison example coefficient and the offset coefficient, thereby ensuring the accuracy of the actual working current finally detected and calculated and eliminating the problem of error of the sampling resistor 400 caused by temperature change.
In some embodiments, adjusting the operating power supply 300 to output the first actual current includes:
the output current of the working power supply 300 is adjusted while detecting the output current of the working power supply 300 by the current detection device until the working power supply 300 outputs the first actual current.
The working power supply 300 cannot detect the current flowing through the sampling resistor 400, so that in order to ensure that the working power supply 300 can output the first actual current, an external current detection device can be utilized to detect the output current of the working power supply 300 in real time until the output current is the first actual current.
In some embodiments, adjusting the operating power supply 300 to output the second actual current includes:
the output current of the working power supply 300 is adjusted while detecting the output current of the working power supply 300 by the current detection device until the working power supply 300 outputs the second actual current.
The working power supply 300 cannot detect the current flowing through the sampling resistor 400, so that in order to ensure that the working power supply 300 can output the second actual current, an external current detection device can be utilized to detect the output current of the working power supply 300 in real time until the output current is the second actual current.
In some embodiments, the theoretical detected current calculated from 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detected current calculated from 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current. The first calibration temperature is 20% of the high threshold of the preset usage environment temperature of the sampling resistor 400, and the second calibration temperature is 80% of the high threshold of the preset usage environment temperature of the sampling resistor 400.
The first actual current and the second actual current are set according to the detection range of the voltage acquisition unit, and it can be understood that a corresponding relationship exists between the detection voltage detected by the voltage acquisition unit and the theoretical detection current calculated by further combining ohm's law, so that the full range of the current can actually correspond to the full range of the voltage, and 20% and 80% of the full range are selected as two measuring points in the embodiment, and the accuracy of the detection can be effectively ensured.
It should be noted that, the temperature of the sampling resistor 400 will change due to the change of the current, and the greater the current, the higher the temperature, and the two measurement points are determined in consideration of the temperature fluctuation range (that is, the upper limit of the temperature fluctuation range may be determined as the preset usage environment temperature high threshold) of the sampling resistor 400 in actual usage, where 20% and 80% are selected as the two measurement points, and correspond to the first actual current and the second actual current, so as to finally obtain two working environments.
In some embodiments, the resistance temperature versus current bias relationship is:
I T ＝I AD *T*{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}+{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}
*I AD *T1}，
wherein I is T Correcting current for temperature deviation, I T1 For the first temperature compensation current, I T2 For the second temperature compensation current, I AD To theoretically detect current, I AD1 For a first calibration current, I AD2 The temperature sensor is characterized in that the temperature sensor is used for measuring a first calibration current, T is a resistance temperature, T1 is a first calibration temperature, and T2 is a second calibration temperature.
And the obtained proportional coefficient and the deviation coefficient are brought into a basic relational expression, so that a relational expression of resistance temperature and current deviation can be obtained, and the theoretical detection current and the resistance temperature can be obtained through measurement and calculation by utilizing the relational expression of resistance temperature and current deviation, so that the temperature deviation correction current can be quickly obtained.
Furthermore, an embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or control module, to cause the processor to perform the high-current sampling method of the above embodiment, for example, to perform the method described above.
Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media or non-transitory media and communication media or transitory media. The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention.
Claims (10)
1. The high-current sampling method is characterized by being applied to a sampling system, wherein the sampling system comprises a voltage acquisition unit and a temperature acquisition unit, the voltage acquisition unit is used for acquiring the detection voltage of a sampling resistor, the temperature acquisition unit is used for acquiring the resistance temperature of the sampling resistor, and the sampling resistor is connected in series with a work load and a work power supply;
the high-current sampling method comprises the following steps:
acquiring the resistance temperature acquired by the temperature acquisition unit;
acquiring the detection voltage acquired by the voltage acquisition unit;
obtaining theoretical detection current according to the detection voltage and the theoretical resistance of the sampling resistor;
obtaining a temperature deviation correction current according to the theoretical detection current, the resistance temperature and a pre-obtained relation between the resistance temperature and the current deviation;
obtaining the actual working current flowing through the working load according to the temperature deviation correction current and the theoretical detection current;
Wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply to output a first actual current, and adjusting the ambient temperature to a first ambient temperature so that the resistance temperature of the sampling resistor reaches a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor;
determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor reaches a second calibration temperature, and acquiring a second calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor;
determining a second temperature compensation current according to the second actual current and the second calibration current;
determining a proportionality coefficient and an offset coefficient of a pre-obtained basic relation according to the first calibration temperature, the first calibration current, the first temperature compensation current, the second calibration temperature, the second calibration current and the second temperature compensation current, wherein the basic relation represents a positive correlation relation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature;
And carrying the proportionality coefficient and the offset coefficient into the basic relation to obtain the relation between the resistance temperature and the current deviation.
2. The method of high current sampling according to claim 1, wherein said adjusting said operating power supply to output a first actual current comprises:
and adjusting the output current of the working power supply, and detecting the output current of the working power supply by using a current detection device until the working power supply outputs the first actual current.
3. The method of high current sampling according to claim 1, wherein said adjusting said operating power supply to output a second actual current comprises:
and adjusting the output current of the working power supply, and detecting the output current of the working power supply by using a current detection device until the working power supply outputs the second actual current.
4. A high current sampling method according to claim 3, wherein the theoretical detection current calculated from 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detection current calculated from 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current.
5. The high current sampling method according to claim 1, wherein the first calibration temperature is 20% of a preset usage environment temperature high threshold of the sampling resistor, and the second calibration temperature is 80% of the preset usage environment temperature high threshold of the sampling resistor.
6. The high current sampling method according to claim 1, wherein the resistance temperature and current deviation relation is:
I T ＝I AD *T*{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}+{I T1 -{(I T1 -I T2 )/[(I AD1 *T1)-(I AD2 *T2)]}
*I AD *T1}，
wherein I is T Correcting current for said temperature deviation, I T1 Compensating the current for the first temperature, I T2 Compensating the current for the second temperature, I AD For the theoretical detection current, I AD1 For the first calibration current, I AD2 And for the first calibration current, T is the resistance temperature, T1 is the first calibration temperature, and T2 is the second calibration temperature.
7. The high-current sampling device is characterized by being applied to a sampling system, wherein the sampling system comprises a voltage acquisition unit and a temperature acquisition unit, the voltage acquisition unit is used for acquiring the detection voltage of a sampling resistor, the temperature acquisition unit is used for acquiring the resistance temperature of the sampling resistor, and the sampling resistor is connected in series with a work load and a work power supply;
The high-current sampling device includes:
the temperature acquisition module is used for acquiring the resistance temperature acquired by the temperature acquisition unit;
the voltage acquisition module is used for acquiring the detection voltage acquired by the voltage acquisition unit;
the theoretical current calculation module is used for obtaining theoretical detection current according to the detection voltage and the theoretical resistance of the sampling resistor;
the corrected current acquisition module is used for acquiring a temperature deviation corrected current according to the theoretical detected current, the resistance temperature and a pre-acquired relation between the resistance temperature and the current deviation;
the current output module is used for correcting the current and the theoretical detection current according to the temperature deviation to obtain the actual working current flowing through the working load;
wherein, the relation between the resistance temperature and the current deviation is obtained by the following steps:
adjusting the working power supply to output a first actual current, and adjusting the ambient temperature to a first ambient temperature so that the resistance temperature of the sampling resistor reaches a first calibration temperature, thereby obtaining a first calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a first calibration current according to the first calibration voltage and the theoretical resistance of the sampling resistor;
Determining a first temperature compensation current according to the first actual current and the first calibration current;
adjusting the working power supply to output a second actual current, and adjusting the ambient temperature to a second ambient temperature so that the resistance temperature of the sampling resistor reaches a second calibration temperature, and acquiring a second calibration voltage of the sampling resistor acquired by the voltage acquisition unit;
determining a second calibration current according to the second calibration voltage and the theoretical resistance of the sampling resistor;
determining a second temperature compensation current according to the second actual current and the second calibration current;
determining a proportionality coefficient and an offset coefficient of a pre-obtained basic relation according to the first calibration temperature, the first calibration current, the first temperature compensation current, the second calibration temperature, the second calibration current and the second temperature compensation current, wherein the basic relation represents a positive correlation relation between the temperature deviation correction current and the product of the theoretical detection current and the resistance temperature;
and carrying the proportionality coefficient and the offset coefficient into the basic relation to obtain the relation between the resistance temperature and the current deviation.
8. The heavy current sampling device of claim 7, wherein the theoretical detected current calculated from 20% of the full range of the voltage acquisition unit corresponds to the first actual current, and the theoretical detected current calculated from 80% of the full range of the voltage acquisition unit corresponds to the second actual current corresponds to the first actual current.
9. The high current sampling apparatus of claim 7 wherein said first calibration temperature is 20% of a predetermined use environment temperature high threshold of said sampling resistor and said second calibration temperature is 80% of the predetermined use environment temperature high threshold of said sampling resistor.
10. A computer-readable storage medium storing computer-executable instructions for causing a computer to perform the high current sampling method according to any one of claims 1 to 6.
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