Common-mode voltage compensation system and method of load high-end voltage sampling system

Abstract

The invention relates to a common-mode voltage compensation system and method for a load high-end voltage sampling system, and belongs to the technical field of high-precision instruments.The system comprises a load two-end voltage sampling unit, a load high-end voltage-to-ground sampling unit and a computer control unit.The load two-end voltage sampling unit is connected to the two ends of a load in parallel; voltage display values at two ends of the load are measured; the load high-end voltage-to-ground sampling unit is connected with the high end of the load and is used for measuring a voltage-to-ground display value of the high end of the load; the computer control unit is used for calculating a common-mode voltage influence value at the two ends of the load according to the voltage display value and the voltage-to-ground display value; and determining the difference value between the voltage display value and the common-mode voltage influence value as the actual voltage at the two ends of the load. The influence of common-mode voltage on voltage measurement at two ends of the load can be eliminated as far as possible, and the requirement of high-precision voltage measurement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision instruments, and in particular to a common-mode voltage compensation system and method for a load high-end voltage sampling system. Background Art

[0002] With the rapid development of the domestic instrument industry, the accuracy of sources and meters in the source meter industry is getting higher and higher. In high-power current source instruments, the load is usually at the high end, resulting in common-mode voltage in the sampling of both ends of the load, affecting the measurement accuracy. Especially when multiple loads are measured in series, the common-mode voltage difference between the first load and the last load is large, affecting the measurement consistency.

[0003] In order to solve this problem, the existing technology uses a high common mode rejection ratio operational amplifier and a high precision matching resistor to attenuate and suppress the influence of the common mode voltage on the measurement accuracy. However, this method can only reduce part of the influence and still cannot meet the requirements of high precision measurement.

[0004] It can be seen that the existing technology cannot meet the requirements of high-precision voltage measurement. Summary of the invention

[0005] In view of this, it is necessary to provide a common-mode voltage compensation system and method for a load high-end voltage sampling system to solve the problem that the prior art cannot meet the requirements of high-precision voltage measurement.

[0006] In order to solve the above problems, the present invention provides a common-mode voltage compensation system for a load high-end voltage sampling system, comprising a load-end voltage sampling unit, a load-end-to-ground voltage sampling unit, and a computer control unit, wherein the load-end voltage sampling unit is connected in parallel to the load ends, and is used to measure the voltage display value at the load ends; The load high-end-to-ground voltage sampling unit is connected to the high-end of the load and is used to measure the displayed value of the load high-end-to-ground voltage; The computer control unit is used to calculate the common mode voltage influence value at both ends of the load according to the voltage display value and the voltage display value to ground; and determine the difference between the voltage display value and the common mode voltage influence value as the actual voltage at both ends of the load.

[0007] In a possible implementation, a voltage sampling unit at both ends of the load is connected in parallel to both ends of the load through a first switch and a second switch, and the first ends of the first switch and the second switch are respectively connected to the two ends of the load, the second ends of the first switch and the second switch are connected to the voltage sampling unit at both ends of the load, and a third switch is connected between the second ends of the first switch and the second switch.

[0008] In a possible implementation manner, the load voltage sampling unit is further used for: When the first switch, the second switch and the third switch are all disconnected, a standard voltage source is connected to the second ends of the first switch and the second switch, and a first relationship between the voltage display value and the actual voltage across the load is determined based on the voltage display value of the voltage sampling unit across the load when different standard voltage sources are connected.

[0009] In a possible implementation manner, the load voltage sampling unit is further used for: When the first switch is open, the second switch is open and the third switch is closed, a standard voltage power source is connected to the ground at the second end of the second switch, according to a third relationship between the actual voltage across the load and the common mode voltage under different standard voltage source connections to the ground.

[0010] In a possible implementation manner, the voltage sampling unit across the load includes: A first operational amplifier, wherein the positive input terminal of the first operational amplifier is connected to the second terminal of the first switch, the negative input terminal of the first operational amplifier is connected to the second terminal of the second switch, the output terminal of the first operational amplifier is connected to the input terminal of the voltage conditioning circuit, and the output terminal of the voltage conditioning circuit is connected to the analog-to-digital converter.

[0011] In a possible implementation, the load high end to ground voltage sampling unit is connected to the high end of the load through a fourth switch, a first end of the fourth switch is connected to the high end of the load, and a second end of the fourth switch is connected to the load high end to ground voltage sampling unit.

[0012] In a possible implementation manner, the load high-end-to-ground voltage sampling unit is further used for: When the fourth switch is disconnected, a standard voltage power source is connected to the ground at the second end of the fourth switch, and a second relationship between the ground voltage display value and the actual voltage at both ends of the load is determined according to the ground voltage display value of the load high-end ground voltage sampling unit under different ground connection standard voltage sources.

[0013] In a possible implementation manner, the load high-end-to-ground voltage sampling unit includes: A second operational amplifier, wherein the positive input terminal of the second operational amplifier is connected to the second end of the fourth switch, the negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is connected to the input terminal of the voltage conditioning circuit, and the output terminal of the voltage conditioning circuit is connected to the analog-to-digital converter.

[0014] In a possible implementation manner, when the computer control unit calculates the common mode voltage impact value across the load according to the voltage display value and the voltage to ground display value, it is configured to: determining a voltage measurement value across the load according to the voltage display value and the first relationship; Determine a measured value of the voltage to ground of the high end of the load according to the displayed value of the voltage to ground and the second relationship; The common mode voltage impact value across the load is determined according to the voltage measurement value and the voltage-to-ground measurement value according to the third relationship.

[0015] The present invention further provides a common-mode voltage compensation method for a load high-end voltage sampling system, which is applicable to a common-mode voltage compensation system for a load high-end voltage sampling system in any of the above embodiments, comprising: Measure the voltage display value at both ends of the load and the voltage display value of the high end of the load to ground; The common-mode voltage influence value at both ends of the load is calculated according to the voltage display value and the voltage-to-ground display value; and the difference between the voltage display value and the common-mode voltage influence value is determined as the actual voltage at both ends of the load.

[0016] The beneficial effects of the present invention are as follows: the common-mode voltage compensation system of the load high-end voltage sampling system provided by the present invention measures the voltage display value at both ends of the load through the voltage sampling units at both ends of the load, measures the low voltage display value to the ground at both ends of the load through the load high-end voltage to ground sampling units, and then calculates the common-mode voltage influence value at both ends of the load according to the voltage display value and the voltage display value to the ground; and determines the difference between the voltage display value and the common-mode voltage influence value as the actual voltage at both ends of the load, which can eliminate the influence of the common-mode voltage on the voltage measurement at both ends of the load as much as possible and meet the needs of high-precision voltage measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A structural schematic diagram of a common-mode voltage compensation system for a load high-end voltage sampling system provided by an embodiment of the present invention; Figure 2 A schematic flow chart of a common-mode voltage compensation method for a load high-end voltage sampling system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0020] The descriptions of "first", "second", etc. involved in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0021] Reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] A specific embodiment of the present invention, as Figure 1 As shown, a common-mode voltage compensation system of a load high-end voltage sampling system is disclosed, comprising a load-end voltage sampling unit 101, a load-end-to-ground voltage sampling unit 102, and a computer control unit 103, wherein the load-end voltage sampling unit 101 is connected in parallel to the load ends, and is used to measure the voltage display value at the load ends; The load high-end-to-ground voltage sampling unit 102 is connected to the high-end of the load and is used to measure the displayed value of the load high-end-to-ground voltage; The computer control unit 103 is used to calculate the common mode voltage impact value across the load according to the voltage display value and the ground voltage display value; and determine the difference between the voltage display value and the common mode voltage impact value as the actual voltage across the load.

[0023] In the embodiment of the present invention, the common-mode voltage compensation system of the load high-end voltage sampling system can be used in high-precision voltage measurement, especially in high-power voltage measurement with the influence of common-mode voltage deviation, and can eliminate the influence of large difference in common-mode voltage between the first load and the last load when measuring loads in series. Specifically, Figure 1 A voltage sampling unit at both ends of the load is connected in parallel to both ends of the load, which is used to measure the voltage display value at both ends of the load when the load is powered on. The voltage display value refers to the value displayed when the voltage sampling unit at both ends of the load measures the voltage at both ends of the load. A load-to-ground voltage measuring unit is connected to the high end of the load connected to the voltage source, which is used to measure the high-end-to-ground voltage display value of the load when the load is powered on. The ground voltage display value refers to the value displayed when the load high-end-to-ground voltage sampling unit measures the ground voltage of the load high-end. The common-mode voltage influence value at both ends of the load is calculated based on the voltage display value and the ground voltage display value; and the difference between the voltage display value and the common-mode voltage influence value is determined as the actual voltage at both ends of the load. The specific common-mode voltage calculation method will be described in detail later in the present invention.

[0024] The common-mode voltage compensation system of the load high-end voltage sampling system provided by the present invention measures the voltage display value at both ends of the load through the voltage sampling units at both ends of the load, measures the low-voltage measurement value of the load to the ground through the load high-end voltage sampling units, and then calculates the common-mode voltage influence value at both ends of the load by the voltage display value and the voltage display value to the ground; and determines the difference between the voltage display value and the common-mode voltage influence value as the actual voltage at both ends of the load, which can eliminate the influence of the common-mode voltage on the voltage measurement at both ends of the load as much as possible and meet the needs of high-precision voltage measurement.

[0025] As a possible implementation mode of the present invention, in this implementation mode, a voltage sampling unit at both ends of the load is connected in parallel to both ends of the load through a first switch and a second switch, and the first ends of the first switch and the second switch are respectively connected to both ends of the load, the second ends of the first switch and the second switch are connected to the voltage sampling unit at both ends of the load, and a third switch is connected between the second ends of the first switch and the second switch.

[0026] In the embodiment of the present invention, Figure 1 As shown, the voltage sampling unit at both ends of the load is connected in parallel to both ends of the load through the first switch K1 and the second switch K2, and the first ends of the first switch K1 and the second switch K2 are respectively connected to the two ends of the load, the second ends of the first switch K1 and the second switch K2 are connected to the voltage sampling unit at both ends of the load, and a third switch K3 is connected between the second ends of the first switch K1 and the second switch K2.

[0027] Furthermore, the voltage sampling unit at both ends of the load is also used for: When the first switch, the second switch and the third switch are all disconnected, a standard voltage source is connected to the second ends of the first switch and the second switch, and a first relationship between the voltage display value and the actual voltage across the load is determined based on the voltage display value of the voltage sampling unit across the load when different standard voltage sources are connected.

[0028] In the embodiment of the present invention, the voltage sampling unit at both ends of the load needs to be calibrated before use. In the calibration state, K1, K2, and K3 are all disconnected, and a standard voltage source inputs voltage from the two ports of K1 and K2. The computer control unit controls U3 to collect the voltage display value , by adjusting the input voltage The value of , the voltage As an independent variable, the input voltage As the dependent variable, the first relationship can be obtained: (1) in, and is the first relationship coefficient.

[0029] As a possible implementation manner of the present invention, in this implementation manner, the voltage sampling unit at both ends of the load is further used for: When the first switch is open, the second switch is open and the third switch is closed, a standard voltage power source is connected to the ground at the second end of the second switch, according to a third relationship between the actual voltage across the load and the common mode voltage under different standard voltage source connections to the ground.

[0030] In the embodiment of the present invention, the common mode voltage of the voltage sampling unit at both ends of the load is measured. At this time, K3 is closed, K1 and K2 are disconnected, and the standard source inputs the voltage from the 2nd port of K2 to the ground. ,at this time The voltage is the common mode voltage of the voltage sampling unit at both ends of the load. At the same time, the voltage collected by U3 is the common mode voltage of the voltage sampling unit at both ends of the load. The measurement deviation under common mode voltage, the voltage displayed by U3 is ; By adjusting the input voltage The value of , the voltage As the dependent variable, the input voltage As the independent variable, the third relationship can be obtained: (2) in, and is the third relationship coefficient.

[0031] As a possible implementation manner of the present invention, in this implementation manner, the voltage sampling unit across the load includes: A first operational amplifier, wherein the positive input terminal of the first operational amplifier is connected to the second terminal of the first switch, the negative input terminal of the first operational amplifier is connected to the second terminal of the second switch, the output terminal of the first operational amplifier is connected to the input terminal of the voltage conditioning circuit, and the output terminal of the voltage conditioning circuit is connected to the analog-to-digital converter.

[0032] In an embodiment of the present invention, the first operational amplifier is used to amplify the collected voltage across the load, and adjust the amplified voltage to within the input range of the analog-to-digital converter through a voltage conditioning circuit. The analog-to-digital converter is used to convert the voltage analog signal into digital information for easy display and calculation.

[0033] Furthermore, the load high end to ground voltage sampling unit is connected to the high end of the load through a fourth switch, a first end of the fourth switch is connected to the high end of the load, and a second end of the fourth switch is connected to the load high end to ground voltage sampling unit.

[0034] In the embodiment of the present invention, Figure 1 As shown, the load high-end-to-ground voltage sampling unit is connected to the 1 end of the first switch through the fourth switch K4, which is also the high-end of the load.

[0035] The load high-end voltage to ground sampling unit is also used for: When the fourth switch is disconnected, a standard voltage power source is connected to the ground at the second end of the fourth switch, and a second relationship between the ground voltage display value and the actual voltage at both ends of the load is determined according to the ground voltage display value of the load high-end ground voltage sampling unit under different ground connection standard voltage sources.

[0036] In the embodiment of the present invention, the load high-end voltage to ground sampling unit also needs to be calibrated. In the calibration state, K4 is disconnected, and a standard voltage source inputs a voltage from the 2 ports of K4 to the ground. The computer control unit controls U7 to collect the voltage display value. , by adjusting the input voltage The value of , the voltage As an independent variable, the input voltage As the dependent variable, the first relationship can be obtained: (3) in, and is the first relationship coefficient.

[0037] The load high-end-to-ground voltage sampling unit includes a second operational amplifier, a positive input terminal of the second operational amplifier is connected to the second end of the fourth switch, a negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is connected to the input terminal of the voltage conditioning circuit, and the output terminal of the voltage conditioning circuit is connected to the analog-to-digital converter.

[0038] Similarly, the voltage conditioning circuit is used to regulate the input voltage so that the output voltage of the voltage conditioning circuit meets the input requirement of the analog-to-digital converter.

[0039] Optionally, when the computer control unit calculates the common mode voltage impact value across the load according to the voltage display value and the voltage to ground display value, it is configured to: determining a voltage measurement value across the load according to the voltage display value and the first relationship; Determine a measured value of the voltage to ground of the high end of the load according to the displayed value of the voltage to ground and the second relationship; The common mode voltage impact value of the two ends of the load is determined according to the third relationship based on the voltage measurement value and the voltage to ground measurement value. In the embodiment of the present invention, when the system is measuring normally, K1, K2, and K4 are all in a closed state, and K3 is in an open state. At this time, the measured value of the high-end voltage of the load to ground is recorded as The measured voltage without compensating the common mode voltage across the load is recorded as , because at this time The measured value includes the common mode voltage part, but the common mode voltage part is much smaller than , so the common mode voltage across the load is approximately equal to 0.5 times , then according to the above equations (1), (2) and (3), we can get (4) (5) (6) Based on this, the voltage across the load after compensating the common-mode voltage can be determined for: (7) Substituting equations (4), (5) and (6) into equation (7) can obtain the accurate value of the actual voltage across the load. Table 1 shows the comparison of the measurement deviation before and after compensation under different common mode voltages across the load using the above system.

[0040] Table 1: The embodiment of the present invention calibrates the voltage sampling unit at both ends of the load and the voltage sampling unit of the load high end to ground, and obtains a first relationship between the voltage display value and the actual voltage at both ends of the load, a second relationship between the voltage display value to ground and the actual voltage at both ends of the load, and a third relationship between the actual voltage and the common mode voltage of the load high end, thereby eliminating the common mode voltage error in the calculation process and ensuring the accuracy of high-precision voltage measurement.

[0041] As a possible implementation mode of the present invention, in this implementation mode, Figure 2 As shown, a common-mode voltage compensation method for a load high-end voltage sampling system is provided, which is applicable to a common-mode voltage compensation system for a load high-end voltage sampling system of any of the above embodiments, comprising: S201, measuring the voltage display value at both ends of the load and the voltage display value of the high end of the load to the ground; S202, calculating a common-mode voltage influence value across the load according to the voltage display value and the voltage-to-ground display value; and determining a difference between the voltage display value and the common-mode voltage influence value as an actual voltage across the load.

[0042] The common-mode voltage compensation method for the load high-end voltage sampling system provided by the present invention has the same principle for eliminating the common-mode voltage error at both ends of the load as the common-mode voltage compensation system for the load high-end voltage sampling system in the aforementioned embodiment, which will not be described in detail here.

[0043] The common-mode voltage compensation method of the load high-end voltage sampling system provided by the present invention measures the voltage display value at both ends of the load through the voltage sampling units at both ends of the load, measures the low-voltage measurement value of the load to the ground through the load high-end voltage sampling unit, and then calculates the common-mode voltage influence value at both ends of the load according to the voltage display value and the voltage display value to the ground; and determines the difference between the voltage display value and the common-mode voltage influence value as the actual voltage at both ends of the load, which can eliminate the influence of the common-mode voltage on the voltage measurement at both ends of the load as much as possible and meet the needs of high-precision voltage measurement.

[0044] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A common-mode voltage compensation system for a load high-end voltage sampling system, characterized in that: It includes a voltage sampling unit at both ends of the load, a voltage sampling unit for the high end of the load to the ground, and a computer control unit, wherein the voltage sampling unit at both ends of the load is connected in parallel to both ends of the load, and is used to measure the voltage display value at both ends of the load; The load high-end-to-ground voltage sampling unit is connected to the high-end of the load and is used to measure the displayed value of the load high-end-to-ground voltage; The computer control unit is used to calculate the common-mode voltage impact value across the load according to the voltage display value and the voltage-to-ground display value; and determine the difference between the voltage display value and the common-mode voltage impact value as the actual voltage across the load.

2. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 1, characterized in that: The voltage sampling unit at both ends of the load is connected in parallel to both ends of the load through a first switch and a second switch, and the first ends of the first switch and the second switch are respectively connected to both ends of the load, the second ends of the first switch and the second switch are connected to the voltage sampling unit at both ends of the load, and a third switch is connected between the second ends of the first switch and the second switch.

3. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 2, characterized in that: The voltage sampling unit at both ends of the load is also used for: When the first switch, the second switch and the third switch are all disconnected, a standard voltage source is connected to the second ends of the first switch and the second switch, and a first relationship between the voltage display value and the actual voltage across the load is determined according to the voltage display value of the voltage sampling unit across the load when different standard voltage sources are connected.

4. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 3, characterized in that: The voltage sampling unit at both ends of the load is also used for: When the first switch is open, the second switch is open and the third switch is closed, a standard voltage power source is connected to the ground at the second end of the second switch, and a third relationship between the actual voltage across the load and the common mode voltage is determined based on different standard voltage sources connected to the ground.

5. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 4, characterized in that: The voltage sampling unit at both ends of the load includes: A first operational amplifier, wherein a positive input terminal of the first operational amplifier is connected to a second terminal of the first switch, a negative input terminal of the first operational amplifier is connected to a second terminal of the second switch, an output terminal of the first operational amplifier is connected to an input terminal of a voltage conditioning circuit, and an output terminal of the voltage conditioning circuit is connected to an analog-to-digital converter.

6. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 5, characterized in that: The load high-end-to-ground voltage sampling unit is connected to the high-end of the load through a fourth switch, a first end of the fourth switch is connected to the high-end of the load, and a second end of the fourth switch is connected to the load high-end-to-ground voltage sampling unit.

7. The common mode voltage compensation system of the load high-end voltage sampling system according to claim 6, characterized in that: The load high-end voltage-to-ground sampling unit is also used for: When the fourth switch is disconnected, a standard voltage power supply is connected to the ground at the second end of the fourth switch, and a second relationship between the ground voltage display value and the actual voltage at both ends of the load is determined according to the ground voltage display value of the load high-end ground voltage sampling unit under different ground connection standard voltage sources.

8. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 7, characterized in that: The load high-end-to-ground voltage sampling unit comprises: a second operational amplifier, wherein the positive input terminal of the second operational amplifier is connected to the second end of the fourth switch, the negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is connected to the input terminal of the voltage conditioning circuit, and the output terminal of the voltage conditioning circuit is connected to the analog-to-digital converter.

9. The common-mode voltage compensation system of the load high-end voltage sampling system according to claim 8, characterized in that: When the computer control unit calculates the common mode voltage impact value at both ends of the load according to the voltage display value and the voltage to ground display value, it is used to: determining a voltage measurement value across the load according to the voltage display value and the first relationship; Determine a measured value of the voltage to ground of the high end of the load according to the displayed value of the voltage to ground and the second relationship; The common mode voltage impact value across the load is determined according to the voltage measurement value and the voltage-to-ground measurement value according to the third relationship.

10. A common-mode voltage compensation method for a load high-end voltage sampling system, applicable to the common-mode voltage compensation system for a load high-end voltage sampling system according to any one of claims 1 to 9, comprising: Measure the voltage display value at both ends of the load and the voltage display value of the high end of the load to the ground; The common-mode voltage influence value at both ends of the load is calculated according to the voltage display value and the voltage-to-ground display value; and the difference between the voltage display value and the common-mode voltage influence value is determined as the actual voltage at both ends of the load.

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