阅读说明：本技术 用于校正分流电阻器的电流值的系统和方法 (System and method for correcting current value of shunt resistor ) 是由 赵现起 朴载东 于 2019-08-26 设计创作，主要内容包括：本发明涉及一种用于校正分流电阻器的电流值的系统和方法,其中,使用分流电阻器的可变温度值来计算电阻变化,并且基于所计算的电阻变化和分流电阻器的两个端子的电压值来计算对应分流电阻器中流动的实时电流值,从而即使分流电阻器的温度值连续地变化,也可以通过反映所有变化而获得精确的电流值。(The present invention relates to a system and method for correcting a current value of a shunt resistor, in which a resistance change is calculated using a variable temperature value of the shunt resistor, and a real-time current value flowing in the corresponding shunt resistor is calculated based on the calculated resistance change and a voltage value of both terminals of the shunt resistor, so that an accurate current value can be obtained by reflecting all changes even if the temperature value of the shunt resistor continuously changes.)

1. A system for correcting a current value of a shunt resistor, the system comprising:

a power calculation unit configured to calculate power consumption and a heating value of the shunt resistor based on a current value of the shunt resistor and a first resistance value of the shunt resistor provided in a circuit;

a temperature measurement unit configured to measure an ambient temperature value of the shunt resistor;

a final temperature value calculation unit configured to calculate a second final temperature value of the shunt resistor and a variation amount of the second final temperature value compared to a first final temperature value before current flows, from a heat generation temperature value of the shunt resistor calculated based on the calculated heat generation value and a thermal resistance coefficient of the shunt resistor and an ambient temperature value of the shunt resistor; and

a resistance calculation unit configured to calculate a second resistance value of the shunt resistor based on the calculated final temperature value change amount of the shunt resistor and a temperature coefficient value of the shunt resistor that changes according to a temperature change.

2. The system of claim 1, further comprising:

a voltage measurement unit configured to detect a voltage value of the shunt resistor when a voltage of the shunt resistor provided on the circuit drops; and

a current calculation unit configured to calculate a current value of the shunt resistor based on the detected voltage value and the first resistance value of the shunt resistor,

wherein the current calculation unit changes the first resistance value to the second resistance value supplied from the resistance calculation unit.

3. The system according to claim 2, wherein the current calculation unit determines a value calculated by the following equation 1 as the current value,

[ formula 1]

I＝V/R，

Here, I is a current value of the shunt resistor, V is a voltage value of the shunt resistor, and R is the first resistance value of the shunt resistor.

4. The system according to claim 1, wherein the power calculation unit determines a value calculated by the following equation 2 as the heating value of the shunt resistor,

[ formula 2]

Here, E is a heating value of the shunt resistor, I is a current value of the shunt resistor, R is the first resistance value of the shunt resistor, and t is a flowing time value of a current flowing in the shunt resistor.

5. The system of claim 1, wherein the temperature measurement unit is disposed adjacent to the shunt resistor.

6. The system according to claim 1, wherein the final temperature value calculation unit determines values calculated by equation 3 below as the second final temperature value and the final temperature value variation of the shunt resistor, and calculates the second final temperature value and the final temperature value variation of the shunt resistor, and then changes the first final temperature value to the second final temperature value,

[ formula 3]

T＝(E*a)+T_a-T_i

Where T is the final temperature value change amount of the shunt resistor, E is the heating value of the shunt resistor, a is the thermal resistivity of the shunt resistor, and T_aIs the ambient temperature, T, of the shunt resistor_iIs a first final temperature value of the shunt resistor.

7. The system according to claim 1, wherein the resistance calculation unit determines a value calculated by the following equation 4 as the second resistance value of the shunt resistor,

[ formula 4]

R＝R_i+(T*b)，

Where R is the second resistance value of the shunt resistor, R_iIs the first resistance value of the shunt resistor, T is the first resistance value of the shunt resistorThe final temperature value variation amount, b is a temperature coefficient of the shunt resistor.

8. A method for correcting a current value of a shunt resistor, the method comprising the steps of:

calculating, by a power calculation unit, a power consumption and a heating value of a shunt resistor based on a current value of the shunt resistor and a first resistance value of the shunt resistor provided in a circuit;

measuring a real-time ambient temperature of the shunt resistor by a temperature measurement unit;

calculating, by a final temperature value calculation unit, a second final temperature value of the shunt resistor and a variation amount of the second final temperature value compared to a first final temperature value before current flows from a heat generation temperature value of the shunt resistor calculated based on the calculated heat generation value and a thermal resistance coefficient of the shunt resistor and an ambient temperature value of the shunt resistor; and

calculating, by a resistance calculation unit, a second resistance value of the shunt resistor based on the final temperature value change amount of the shunt resistor and a temperature coefficient value of the shunt resistor that changes according to a temperature change.

9. The method of claim 8, wherein calculating the current value of the shunt resistor comprises:

determining a value calculated by the following equation 1 as the current value by a current calculation unit; and

changing the first resistance value to the second resistance value supplied from the resistance calculation unit,

[ formula 1]

I＝V/R

Here, I is a current value of the shunt resistor, V is a voltage value of the shunt resistor, and R is a first resistance value of the shunt resistor.

10. The method according to claim 8, wherein the step of calculating the power consumption and the calorific value of the shunt resistor includes determining a value calculated by the following equation 2 as a calorific value of the shunt resistor,

[ formula 2]

Here, E is a heating value of the shunt resistor, I is a current value of the shunt resistor, R is the first resistance value of the shunt resistor, and t is a flowing time value of a current flowing in the shunt resistor.

11. The method of claim 8, wherein the step of calculating the second final temperature value of the shunt resistor and the amount of change in the second final temperature value as compared to the first final temperature value before current flow comprises the steps of:

determining a value calculated by the following equation 3 as the second final temperature value and the final temperature value variation amount of the shunt resistor; and

calculating the second final temperature value and the final temperature value variation of the shunt resistor, and then changing the first final temperature value to the second final temperature value,

[ formula 3]

T＝(E*a)+T_a-T_i

Where T is the final temperature value change amount of the shunt resistor, E is the heating value of the shunt resistor, a is the thermal resistivity of the shunt resistor, and T_aIs the ambient temperature, T, of the shunt resistor_iIs the first final temperature value of the shunt resistor.

12. The method of claim 8, wherein the calculating of the second resistance value of the shunt resistor includes determining a value calculated by equation 4 below as the second resistance value of the shunt resistor,

[ formula 4]

R＝R_i+(T*b)

Where R is the second resistance value of the shunt resistor, R_iIs the first resistance value of the shunt resistor, T is the final temperature value variation amount of the shunt resistor, and b is a temperature coefficient of the shunt resistor.

Technical Field

This application claims priority and benefit from korean patent application No.10-2018-0103671 filed in the korean intellectual property office at 31.8.2018, the entire contents of which are incorporated herein by reference.

The present invention relates to a system and method for correcting a current value of a shunt resistor, which calculates a variation amount of a resistance value by using a variable temperature value of the shunt resistor and calculates a real-time current value flowing in the corresponding shunt resistor based on the calculated variation amount of the resistance value and a voltage value of both terminals of the shunt resistor, so that an accurate current value can be obtained by reflecting all changes even if the temperature value of the shunt resistor continuously varies.

Background

Generally, as a method of using a shunt resistor in a current system, a method of measuring a current value is used. In the method of measuring a current flowing through a shunt resistor, a temperature of the shunt resistor varies due to heat of the shunt resistor when the current flows through, and when a variation amount of a resistance value due to the varying temperature of the shunt resistor is not considered, a measured current value may have an error.

In addition, since the temperature of the shunt resistor made of metal is abruptly changed according to a heating value due to material characteristics, there is a problem that the abrupt temperature change of the shunt resistor cannot be measured in real time using a general-purpose temperature sensor having a low sensing response speed.

Disclosure of Invention

Technical problem

The present invention has been conceived in order to solve these problems, and an object of the present invention is to provide a system and method for correcting a current value of a shunt resistor, which can obtain an accurate current value by reflecting all changes even if the temperature value of the shunt resistor continuously changes, by calculating a variation amount of a resistance value using a variable temperature value of the shunt resistor and calculating a real-time current value flowing in the corresponding shunt resistor based on the calculated variation amount of the resistance value and voltage values of both terminals of the shunt resistor.

Technical scheme

An exemplary embodiment of the present invention provides a system for correcting a current value of a shunt resistor, the system including: a power calculation unit configured to calculate power consumption and a heating value of the shunt resistor based on a current value of the shunt resistor and a first resistance value of the shunt resistor provided in a circuit; a temperature measurement unit configured to measure an ambient temperature value of the shunt resistor; a final temperature value calculation unit configured to calculate a second final temperature value of the shunt resistor and a variation amount of the second final temperature value compared to a first final temperature value before current flows, from a heat generation temperature value of the shunt resistor calculated based on the calculated heat generation value and a thermal resistance coefficient of the shunt resistor and an ambient temperature value of the shunt resistor; and a resistance calculation unit configured to calculate a second resistance value of the shunt resistor based on the calculated final temperature value change amount of the shunt resistor and a temperature coefficient value of the shunt resistor that changes according to a temperature change.

In an exemplary embodiment, the system may further include: a voltage measurement unit configured to detect a voltage value of the shunt resistor when a voltage of the shunt resistor provided on the circuit drops; and a current calculation unit configured to calculate a current value of the shunt resistor based on the detected voltage value and a first resistance value of the shunt resistor, wherein the current calculation unit may change the first resistance value to the second resistance value supplied from the resistance calculation unit.

In an exemplary embodiment, the current calculation unit may determine a value calculated by the following equation 1 as the current value.

[ formula 1]

I＝V/R

(Here, I is a current value of the shunt resistor, V is a voltage value of the shunt resistor, and R is a first resistance value of the shunt resistor)

In an exemplary embodiment, calculating the power consumption and the heating value of the shunt resistor may include determining a value calculated by equation 2 below as the heating value of the shunt resistor.

[ formula 2]

(Here, E is a heating value of the shunt resistor, I is a current value of the shunt resistor, R is a first resistance value of the shunt resistor, and t is a flowing time value of a current flowing in the shunt resistor)

In an exemplary embodiment, the present invention may include: determining a value calculated by the following equation 3 as the second final temperature value and the final temperature value variation amount of the shunt resistor; and calculating the second final temperature value and the final temperature value variation of the shunt resistor, and then changing the first final temperature value to the second final temperature value.

[ formula 3]

T＝(E*a)+T_a-T_i

(where T is the final temperature value change amount of the shunt resistor, E is the heating value of the shunt resistor, a is the thermal resistivity of the shunt resistor, and T is_aIs the ambient temperature, T, of the shunt resistor_iIs the first final temperature value of the shunt resistor)

In an exemplary embodiment, the calculation of the second resistance value of the shunt resistor and the changing of the first resistance value to the second resistance value by providing the second resistance value to the current calculation unit may include determining a value calculated by equation 4 below as the second resistance value of the shunt resistor.

[ formula 4]

R＝R_i+(T*b)

(where R is the second resistance value of the shunt resistor, R_iIs the first resistance value of the shunt resistor, T is the final temperature value variation magnitude of the shunt resistor, b is the temperature coefficient of the shunt resistor)

Another exemplary embodiment of the present invention provides a method for correcting a current value of a shunt resistor, the method including: calculating, by a power calculation unit, a power consumption and a heating value of a shunt resistor based on a current value of the shunt resistor and a first resistance value of the shunt resistor provided in a circuit; measuring a real-time ambient temperature of the shunt resistor by a temperature measurement unit; calculating, by a final temperature value calculation unit, a second final temperature value of the shunt resistor and a variation amount of the second final temperature value compared to a first final temperature value before current flows from a heat generation temperature value of the shunt resistor calculated based on the calculated heat generation value and a thermal resistance coefficient of the shunt resistor and an ambient temperature value of the shunt resistor; and calculating, by a resistance calculation unit, a second resistance value of the shunt resistor based on the final temperature value change amount of the shunt resistor and a temperature coefficient value of the shunt resistor that changes according to a temperature change.

In an exemplary embodiment, calculating the current value of the shunt resistor may include: determining, by the current calculation unit, a value calculated by equation 1 below as the current value; and changing the first resistance value to the second resistance value supplied from the resistance calculation unit.

[ formula 1]

I＝V/R

(Here, I is a current value of the shunt resistor, V is a voltage value of the shunt resistor, and R is a first resistance value of the shunt resistor)

In an exemplary embodiment, the power calculation unit may determine a value calculated by the following equation 2 as the heating value of the shunt resistor.

[ formula 2]

(Here, E is a heating value of the shunt resistor, I is a current value of the shunt resistor, R is a first resistance value of the shunt resistor, and t is a flowing time value of a current flowing in the shunt resistor)

In an exemplary embodiment, the temperature measurement unit may be positioned adjacent to the shunt resistor.

In an exemplary embodiment, a value calculated by equation 3 below may be determined as the second final temperature value and the final temperature value variation of the shunt resistor, and the second final temperature value and the final temperature value variation of the shunt resistor may be calculated, and then the first final temperature value may be changed to the second final temperature value.

[ formula 3]

T＝(E*a)+T_a-T_i

(where T is the final temperature value change amount of the shunt resistor, E is the heating value of the shunt resistor, a is the thermal resistivity of the shunt resistor, and T is_aIs the ambient temperature, T, of the shunt resistor_iIs the first final temperature value of the shunt resistor)

In an exemplary embodiment, the resistance calculation unit may determine a value calculated by equation 4 below as the second resistance value of the shunt resistor.

[ formula 4]

R＝R_i+(T*b)

(where R is a second resistance value of the shunt resistor, R_iIs the first resistance value of the shunt resistor, T is the final temperature value variation of the shunt resistor, b is the temperature coefficient of the shunt resistor)

Advantageous effects

The system and method for correcting a current value of a shunt resistor according to an exemplary embodiment of the present invention calculates a variation amount of a resistance value by using a variable temperature value of the shunt resistor and calculates a real-time current value flowing in the corresponding shunt resistor based on the calculated variation amount of the resistance value and a voltage value of both terminals of the shunt resistor, so that an accurate current value can be obtained by reflecting all changes even if the temperature value of the shunt resistor continuously varies.

Drawings

Fig. 1 is a diagram showing the configuration of a system 100 for correcting the current value of a shunt resistor according to an exemplary embodiment of the present invention.

Fig. 2 is a flowchart for describing a process of correcting a current value by the system 100 for correcting a current value of a shunt resistor according to an exemplary embodiment of the present invention.

Detailed Description

Hereinafter, exemplary embodiments are provided to aid understanding of the present invention. However, the following exemplary embodiments are provided only for easier understanding of the present invention, and the contents of the present invention are not limited by the exemplary embodiments.

Fig. 1 is a diagram showing the configuration of a system 100 for correcting the current value of a shunt resistor according to an exemplary embodiment of the present invention.

Referring to fig. 1, a system 100 for correcting a current value of a shunt resistor according to an exemplary embodiment of the present invention may include a voltage measuring unit 101, a current calculating unit 102, a power calculating unit 103, a temperature measuring unit 104, a final temperature value calculating unit 105, and a resistance calculating unit 106 electrically connected to a shunt resistor 10.

First, the voltage measurement unit 101 may be connected to both terminals of the shunt resistor 10 provided in the circuit, and detect the voltage value of the shunt resistor 10 when the voltage drops due to the current flow in the shunt resistor 10.

Next, the current calculation unit 102 may calculate a value of a current flowing in the shunt resistor 10 based on the detected voltage value and a first resistance value of the shunt resistor 10, and change the first resistance value to a second resistance value supplied from the resistance calculation unit 106 to be described below.

Here, the first resistance value may refer to a resistance value of the shunt resistor 10 itself.

In addition, the second resistance value is a changed resistance value of the shunt resistor 10, and may refer to a value of the shunt resistor 10 calculated from the resistance calculation unit 106 to be described below.

In addition, the current calculation unit 102 may determine a value calculated by the following equation 1 as a value of the current flowing in the shunt resistor 10.

[ formula 1]

I＝V/R

(here, I is a current value of the shunt resistor, V is a voltage value of the shunt resistor, and R is a first resistance value of the shunt resistor.)

Here, the first resistance value is changed to the second resistance value calculated by the resistance calculation unit 106 to be described below, so that the values of I and V can be changed.

Next, the power calculation unit 103 may calculate the power consumption and the heating value of the shunt resistor 10 based on the calculated current value and the resistance value.

Here, the power calculation unit 103 may determine a value calculated by the following equation 2 as a heat generation value of the shunt resistor.

[ formula 2]

(here, E is a heating value of the shunt resistor, I is a current value of the shunt resistor, R is a first resistance value of the shunt resistor, and t is a flowing time value of a current flowing in the shunt resistor.)

Here, I²R is the power consumption of the shunt resistor 10, the time when the current flowing through the shunt resistor 10 flows versus I²When integrating R, the heating value of the shunt resistor 10 can be calculated.

Next, the temperature measuring unit 104 may measure an ambient temperature value of the shunt resistor 10, and transmit the measured ambient temperature value to the final temperature value calculating unit 105.

Here, the ambient temperature is the temperature of the medium in the vicinity of the device, and may refer to the atmospheric temperature in normal circumstances.

Next, the final temperature value calculation unit 105 may calculate a second final temperature value of the shunt resistor 10 and a variation amount of the second final temperature value compared to the first final temperature value before the current flows from the heat generation temperature value of the shunt resistor 10 calculated based on the calculated heat generation value and the thermal resistance coefficient of the shunt resistor 10 and the ambient temperature value of the shunt resistor 10 (transmitted from the temperature measurement unit 104), and calculate the second final temperature value and the final temperature value variation amount of the shunt resistor, and then change the first final temperature value to the second final temperature value.

Here, the first final temperature value is a temperature value obtained by summing the heat generation temperature value of the shunt resistor 10 and the ambient temperature value, and may refer to a final temperature value of the shunt resistor 10 before the current flows in the shunt resistor 10.

In addition, the second final temperature value is a temperature value obtained by summing the heat generation temperature value of the shunt resistor 10 and the ambient temperature value, and refers to the temperature value of the shunt resistor 10 calculated from the final temperature value calculation unit 105.

In addition, the final temperature value calculation unit 105 may determine the value calculated by equation 3 as the second final temperature value and the final temperature value variation amount of the shunt resistor.

[ formula 3]

T＝(E*a)+T_a-T_i

(where T is the amount of change in the final temperature value of the shunt resistor, E is the heating value of the shunt resistor, a is the thermal resistivity of the shunt resistor, and T_aIs the ambient temperature, T, of the shunt resistor_iIs the first final temperature value of the shunt resistor. )

Here, E × a is a heat generation temperature value of the shunt resistor 10, and when the heat generation temperature value is added to the ambient temperature of the shunt resistor 10, a second final temperature value of the shunt resistor 10 may be calculated, and a difference between the second final temperature value and the first final temperature value may refer to a final temperature value change amount.

In addition, the thermal resistivity of the shunt resistor 10 may refer to a degree intended to interfere with the inherent characteristics of heat transfer to the material constituting the shunt resistor 10.

Next, the resistance calculation unit 106 may calculate the second resistance value of the shunt resistor 10 based on the amount of change in the second final temperature value compared to the first final temperature value of the shunt resistor 10 before the current flows and the temperature coefficient value of the shunt resistor 10 that changes according to the temperature change.

In addition, the resistance calculation unit 106 may determine a value calculated by equation 4 below as the second resistance value of the shunt resistor 10.

[ formula 4]

R＝R_i+(T*b)

(where R is the second resistance value of the shunt resistor, R_iIs a first resistance value of the shunt resistor, T is a final temperature value variation value of the shunt resistor, and b is a temperature coefficient of the shunt resistor. )

Here, T × b is a resistance value due to variation of the shunt resistor 10, and when the value is added to the first resistance value of the shunt resistor 10, the second resistance value of the shunt resistor 10 can be calculated.

Here, the temperature coefficient of the shunt resistor 10 may refer to a degree to which the shunt resistor 10 changes according to a temperature change.

Next, a process of correcting the current by the system for correcting the current value of the shunt resistor will be described with reference to fig. 2.

Fig. 2 is a flowchart for describing a process of correcting a current by the system for correcting a current value of a shunt resistor shown in fig. 1.

Referring to fig. 2, first, the voltage measuring unit measures a voltage value of the shunt resistor (S201), the current calculating unit calculates a current value flowing in the shunt resistor based on the measured voltage value and the shunt resistance value (S202), the power calculating unit calculates a power consumption and a heat generation value of the shunt resistor based on the calculated current value and the shunt resistance value (S203), and in this case, the heat generation value is calculated by a method of integrating the power consumption of the shunt resistor by a time when the current flows in the shunt resistor.

Next, the final temperature calculation unit calculates a second final temperature value and a final temperature value variation of the shunt resistor from the heat generation temperature value of the shunt resistor calculated based on the calculated heat generation value and the thermal resistance coefficient of the shunt resistor and the ambient temperature value of the shunt resistor (S204), and when the final temperature value variation is calculated, the final temperature calculation unit provides the final temperature value variation to the resistance calculation unit and then changes the first final temperature value to the second final temperature value.

Next, the resistance calculation unit calculates a second resistance value of the shunt resistor based on the calculated final temperature value change amount and the temperature coefficient of the shunt resistor (S205), and provides the calculated second resistance value to the current calculation unit to change the first resistance value to the second resistance value (S206).

The present invention has been described above with reference to exemplary embodiments thereof, but those skilled in the art will recognize that various modifications and changes can be made thereto without departing from the spirit and scope of the present invention described in the appended claims.