A precision resistance measuring device under high voltage conditions

Abstract

A precision resistance measuring device for high-voltage environments is disclosed. The device mainly comprises a high-voltage detection unit, a high-voltage isolation unit, and a high-precision resistance measuring circuit. An external signal is simultaneously input to both the high-voltage detection unit and the high-voltage isolation unit. The high-voltage detection unit performs high-voltage detection on the input signal. If no high-voltage input is detected, the signal passes undamaged through the high-voltage isolation unit to the high-precision resistance measuring circuit for normal resistance measurement. If a high-voltage input is present, the high-voltage detection unit controls the high-voltage isolation unit to disconnect from the high-precision resistance measuring circuit, providing continuous high-voltage protection for the measuring equipment until the high-voltage signal stops input. This device provides effective protection for high-precision resistance measurement over a large dynamic range under high-voltage environments.

Description

Technical Field

[0001] This invention relates to the field of high voltage and insulation technology, and in particular to a precision resistance measuring device under high voltage conditions. Background Technology

[0002] High-precision resistance measurement is needed and applied in various environments, especially in the field of 6.5-digit and above high-precision measurement, where the demand is growing. Based on the high requirements for resistance measurement accuracy in fields such as new energy and aerospace, high-precision measurement in high-voltage environments has become necessary. Currently, the protection voltage of commonly used high-precision multimeters for resistance measurement cannot meet these requirements. Especially when the measurement accuracy reaches the 50ppm level, conventional methods such as voltage regulator circuits and high-voltage MOS switching circuits cannot protect the resistance measurement circuit against external high-voltage signals of 4kV and above. Summary of the Invention

[0003] In view of this, the present disclosure provides a precision resistance measuring device under high voltage environment, which mainly solves the problem of high-precision resistance measurement under high voltage environment.

[0004] The device mainly includes: a high-precision resistance measurement circuit, a high-voltage detection unit, and a high-voltage isolation unit, wherein: External signals are simultaneously input to the high-voltage detection unit and the high-voltage isolation unit; The high-voltage detection unit is used to detect high voltage in the input signal. If no high voltage input is detected, the signal passes through the high-voltage isolation unit without loss and reaches the high-precision resistance measurement circuit for normal resistance measurement. If a high voltage input is present, the high-voltage detection unit controls the high-voltage isolation unit to disconnect from the high-precision resistance measurement circuit, providing continuous high-voltage protection for the measuring equipment until the high-voltage signal stops being input.

[0005] Furthermore, the high-precision resistance measurement circuit employs a common constant current source or constant voltage source method.

[0006] Furthermore, the high-precision resistance measurement circuit outputs a measurement current from 100mA to 100nA and a maximum measurement voltage of 200V, enabling high-precision measurement of resistances from 1Ω to 20GΩ.

[0007] Furthermore, the high-voltage detection unit includes a high-voltage differential voltage divider circuit and a signal comparison circuit, wherein: The high-voltage differential voltage divider circuit uses multiple high-voltage-resistant resistors for voltage division; after voltage division, the signal enters the signal comparison circuit, which includes: a DAC, a comparator, and a gate driver circuit; The high-voltage isolation unit uses a high-voltage relay as a switching switch; the contacts of the high-voltage relay are connected in series in the transmission path of the input signal. Under normal conditions, the contacts are closed and the signal passes through normally; after being triggered, the contacts open, forming a physical circuit break. If the signal voltage is greater than the DAC preset voltage, the comparator outputs a high level, triggering the gate circuit, driving the high-voltage relay coil to be energized, opening the contacts, and preventing the signal from passing through; If the signal voltage is less than or equal to the DAC preset voltage, the comparator outputs a low level, the gate circuit does not operate, the high-voltage isolation unit is in the conducting state, and the signal is transmitted normally into the high-precision resistance measurement circuit for resistance measurement.

[0008] Furthermore, the high-voltage differential voltage divider circuit selects different high-voltage withstand resistors and different voltage divider schemes based on the maximum possible voltage in the measurement environment.

[0009] In this disclosure, when an external high voltage is detected during normal resistance signal measurement, the resistance measurement circuit is disconnected by a protection circuit, stopping the output of the constant current source and resistance detection; when the high voltage disappears, the protection self-recovers and the resistance measurement restarts.

[0010] Compared with the prior art, the beneficial effects of this disclosure are: (1) High-precision resistance measurement: meets the high-precision index requirements of resistance measurement; (2) Large dynamic range resistance measurement: meets the high-precision measurement from 1Ω to 20GΩ; (3) Self-recovery protection: provides protection against sudden high voltage during measurement and safely switches to high voltage protection state. After the high voltage disappears, the measurement can be automatically restored; (4) Transient protection: a transient protection circuit is formed by using a comparator, a high voltage isolation unit and digital circuits; (5) Long-term protection: the high voltage protection state can withstand high voltage for a long time and ensure the normal operation of the measuring equipment. Attached Figure Description

[0011] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0012] Figure 1 This is a block diagram illustrating the principle of precision resistance measurement under high voltage conditions disclosed herein. Figure 2 This is a schematic diagram of the high-voltage detection unit in an exemplary embodiment. Detailed Implementation

[0013] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0014] This disclosure provides a precision resistance measuring device for high-voltage operating environments, mainly comprising: a high-voltage detection unit, a high-voltage isolation unit, and a high-precision resistance measuring circuit, wherein: External signals are simultaneously input to the high-voltage detection unit and the high-voltage isolation unit; The high-voltage detection unit is used to detect high voltage in the input signal. If no high voltage input is detected, the signal passes through the high-voltage isolation unit without loss and reaches the high-precision resistance measurement circuit for normal resistance measurement. If a high voltage input is present, the high-voltage detection unit controls the high-voltage isolation unit to disconnect from the high-precision resistance measurement circuit, providing continuous high-voltage protection for the measuring equipment until the high-voltage signal stops being input.

[0015] In one exemplary implementation, the system composition principle block diagram is shown in the appendix. Figure 1 As shown.

[0016] When the high-voltage detection unit detects an external high-voltage environment, it activates the high-voltage isolation unit to ensure the normal operation of the equipment. The high-voltage isolation unit enables the measuring equipment to continuously protect the normal operation of the equipment under the maximum protection voltage. The high-precision resistance measurement circuit can measure resistances from 1Ω to 20GΩ with high precision.

[0017] 1. High-precision resistance measurement solution with large dynamic range under high voltage protection This embodiment is mainly aimed at providing effective long-term protection for a high-precision resistance measurement unit and ensuring the normal operation of resistance measurement under continuous kV-level high voltage conditions.

[0018] For high-voltage protection, it is necessary to ensure that the measuring equipment can operate continuously for a long time under the maximum protection voltage without damage, while guaranteeing measurement accuracy.

[0019] The principle of this embodiment is as follows: Figure 1 As shown, when an external signal enters the measurement unit, unlike conventional measurement schemes, a high-voltage detection unit is used instead of the usual protection circuit. The high-voltage detection unit consists of multiple high-voltage withstand resistors and a voltage comparison circuit; the specific scheme is detailed in the "High-Voltage Detection Unit" section below.

[0020] Then, the high-voltage detection unit determines the current status. If there is no high-voltage input, the high-voltage protection unit is in the conducting state, and the signal passes through the high-voltage isolation unit without loss, allowing the high-precision resistance measurement unit to measure the resistance signal normally. If there is a high-voltage input, the high-voltage isolation unit disconnects from the high-precision resistance measurement unit, providing continuous high-voltage protection for the measuring equipment until the high-voltage signal stops being input.

[0021] High-precision resistance measurement employs a common constant current / constant voltage source method, with output current ranging from 100mA to 100nA and a maximum output voltage of 200V. Under normal measurement conditions, the high-voltage isolation unit is fully conductive, allowing the constant current source and high-voltage measurement signals to be output to the object under test without loss through this unit circuit for measurement.

[0022] 2. Transient protection and high-reliability protection scheme based on self-recovery The challenges in measuring resistance in high-voltage environments are: random high-voltage signals may be encountered during resistance measurement; the measurement requires the resistance measuring equipment to provide a prompt when a high-voltage signal appears; and the resistance measuring equipment must automatically resume measurement after the high-voltage signal disappears.

[0023] Therefore, the protection scheme for resistance measurement equipment needs to provide transient protection, self-recovery protection, and high-reliability protection for long-term high-voltage signals.

[0024] In this embodiment, the main function of "transient protection and high reliability protection based on self-recovery" is in the high-voltage detection unit, such as... Figure 2 As shown, it mainly includes: a high-voltage differential voltage divider circuit and a signal comparison circuit; the output terminal of the signal comparison circuit is connected to the access switch of the high-voltage isolation unit. In this embodiment, a high-voltage relay is used as the access switch.

[0025] The high-voltage differential voltage divider circuit uses multi-stage high-voltage withstand resistors. Different high-voltage withstand resistors and different voltage divider schemes are selected according to the maximum possible voltage in the measurement environment. Considering the variability of the measurement environment, a wider range of adaptability can be achieved by adding a multi-channel high-voltage relay array.

[0026] The signal enters the signal comparison circuit through a high-voltage differential voltage divider circuit. The comparison circuit consists of a DAC, a comparator, and a gate circuit. The gate circuit is used to activate the high-voltage isolation unit. If the input voltage is greater than the preset value output by the DAC, the comparator outputs a high level, triggering the gate circuit and activating the high-voltage isolation unit, thus blocking the signal from passing through. If the input voltage signal is less than the preset value, the comparator outputs a low level, the gate circuit does not activate, the high-voltage isolation unit is in the conducting state, and the input signal is transmitted to the high-precision resistance measurement unit for resistance measurement.

[0027] In this embodiment, the external input signal is divided by a high-voltage differential voltage-dividing circuit, and the comparator and gate circuit control the high-voltage isolation unit to monitor the external input voltage in real time, output the correct resistance measurement result and high-voltage signal alarm to the user, and provide transient and recoverable protection for the resistance measurement unit.

[0028] When the high-voltage isolation unit is turned on, the input signal V1 only enters the multi-stage high-voltage-resistant resistor circuit and is in an open circuit state with other circuits. The maximum withstand voltage sum of the multi-stage high-voltage-resistant resistors is Vmax. When the input signal V1 is configured as a differential input, as long as V1 < Vmax, the circuit is always in a safe state, thus achieving long-term high-reliability protection.

[0029] The above technical solution is only an exemplary embodiment of the present invention. For those skilled in the art, based on the disclosed application methods and principles of the present invention, it is very easy to make various types of improvements or deformations, not limited to the methods described in the above specific embodiments of the present invention. Therefore, the previously described method is only preferred and does not have a restrictive meaning.

Claims

1. A precision resistance measuring device under high voltage conditions, characterized in that, include: The circuit comprises a high-voltage detection unit, a high-voltage isolation unit, and a high-precision resistance measurement circuit, wherein: External signals are simultaneously input to the high-voltage detection unit and the high-voltage isolation unit; The high-voltage detection unit is used to detect high voltage in the input signal. If no high voltage input is detected, the signal passes through the high-voltage isolation unit without loss and reaches the high-precision resistance measurement circuit for normal resistance measurement. If a high voltage input is present, the high-voltage detection unit controls the high-voltage isolation unit to disconnect from the high-precision resistance measurement circuit, providing continuous high-voltage protection for the measuring equipment until the high-voltage signal stops being input.

2. The apparatus according to claim 1, characterized in that, The high-precision resistance measurement circuit uses a common constant current source or constant voltage source method.

3. The apparatus according to claim 2, characterized in that, The high-precision resistance measurement circuit outputs a measurement current from 100mA to 100nA and a maximum output measurement voltage of 200V, enabling high-precision measurement of resistances from 1Ω to 20GΩ.

4. The apparatus according to any one of claims 1-3, characterized in that, The high-voltage detection unit includes a high-voltage differential voltage divider circuit and a signal comparison circuit, wherein: The high-voltage differential voltage divider circuit uses multiple high-voltage-resistant resistors for voltage division; after voltage division, the signal enters the signal comparison circuit, which includes: a DAC, a comparator, and a gate driver circuit; The high-voltage isolation unit uses a high-voltage relay as a switching switch; the contacts of the high-voltage relay are connected in series in the transmission path of the input signal. Under normal conditions, the contacts are closed and the signal passes through normally; after being triggered, the contacts open, forming a physical circuit break. If the signal voltage is greater than the DAC preset voltage, the comparator outputs a high level, triggering the gate circuit, driving the high-voltage relay coil to be energized, opening the contacts, and preventing the input signal from passing through; If the signal voltage is less than or equal to the DAC preset voltage, the comparator outputs a low level, the gate circuit does not operate, the high-voltage isolation unit is in the conducting state, and the input signal is transmitted normally into the high-precision resistance measurement circuit for resistance measurement.

5. The apparatus according to claim 4, characterized in that, The high-voltage differential voltage divider circuit selects different high-voltage withstand resistors and different voltage divider schemes based on the maximum possible voltage in the measurement environment.

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