CN-121995097-A - High-voltage high-precision measuring device

CN121995097ACN 121995097 ACN121995097 ACN 121995097ACN-121995097-A

Abstract

The high-voltage high-precision measuring device mainly comprises a high-voltage attenuation and input protection module, a differential input and signal conditioning module and a high-precision measuring and processing module which are connected in sequence, wherein the high-voltage attenuation and input protection module is used for attenuating an input direct-current high-voltage signal to a low-voltage range which can be processed by a subsequent circuit according to a preset proportion, the differential input and signal conditioning module is used for identifying and extracting a differential mode voltage signal between two input ends, namely an effective signal, and simultaneously greatly inhibiting common mode noise of the two input ends, and the high-precision measuring and processing module is used for performing high-precision voltage measurement after converting the differential analog signal into a single-ended signal through advanced conditioning, performing analog-to-digital conversion and uploading the single-ended signal to a processor through noise isolation. The device builds a safe protection and anti-interference system with reliable grading, can realize high-voltage high-precision measurement, and can realize the highest 7.5-bit high-voltage measurement precision.

Inventors

LI HUIHUI
ZHOU XINPING
WEI JIANRONG
YANG LIJIE
ZHAO JIANGJING
WANG RUI
WANG YING
ZOU PU
ZHANG JIALIN
SHANG YACHAO

Assignees

北京航天测控技术有限公司

Dates

Publication Date: 20260508
Application Date: 20251230

Claims (6)

1. The high-voltage high-precision measuring device is characterized by comprising a high-voltage attenuation and input protection module, a differential input and signal conditioning module and a high-precision measuring and processing module which are connected in sequence, wherein: The high-voltage attenuation and input protection module is used for attenuating an input direct-current high-voltage signal to a low-voltage range which can be processed by a subsequent circuit according to a preset proportion; The differential input and signal conditioning module is used for identifying and extracting a differential mode voltage signal between two input ends, namely an effective signal, and simultaneously, greatly inhibiting common mode noise of the two input ends; the high-precision measuring and processing module converts the differential analog signal into a single-ended signal through pre-conditioning, then performs high-precision voltage measurement, performs analog-to-digital conversion, and finally uploads the signal to the processor through noise isolation.
2. The apparatus of claim 1, wherein the high voltage attenuation and input protection module comprises a resistor divider network and a back-end protection unit, wherein: the resistor voltage dividing network comprises two groups of resistor attenuation networks formed by connecting a plurality of high-precision high-voltage resistors in series, and the two groups of networks respectively correspond to the positive input end and the negative input end of high voltage and are used for converting the input high voltage into a low voltage signal in proportion through the voltage dividing action of the resistors; The rear end protection unit is arranged between the output ends of the resistor voltage-dividing network, adopts a bidirectional voltage-stabilizing tube and is used for voltage monitoring and performing transient overvoltage clamping protection on the rear-stage differential input end when the voltage-dividing circuit fails and high voltage is connected in series.
3. The apparatus of claim 2, wherein the voltage divider network has a decay ratio of 500:1.
4. The apparatus of claim 1, wherein in the differential input and signal conditioning module, the positive and negative low voltage terminals of the output of the high voltage attenuation and input protection module are respectively connected to the in-phase and anti-phase input terminals of the zero drift amplifier, the original high voltage differential signal is converted into a low voltage single-ended signal with reference to signal ground, and the attenuated signal is accurately amplified by configuring an external gain resistor of the precision amplifier so that the amplitude of the attenuated signal matches the input range of the post-stage ADC.
5. The apparatus of any one of claims 1-4, wherein the high precision measurement and processing module comprises: the analog-to-digital conversion part is used for sampling and digitizing the differential analog signals conditioned by the front stage, and is internally provided with a digital filter for suppressing power frequency noise; The MCU is used for finishing nonlinear correction of data and temperature drift compensation of signals, amplifying the measured low voltage value to obtain an original high voltage value, and outputting a measurement result through the isolation interface; An isolated SPI communication channel constructed by a high-speed optical coupler chip is arranged between the analog-digital conversion part and the microprocessor and used for cutting off a ground loop and preventing the front-end high-voltage ground noise from being coupled to a digital system.
6. The apparatus of claim 5, wherein the analog-to-digital conversion portion employs a high resolution, low noise sigma-delta ADC.

Description

High-voltage high-precision measuring device Technical Field The invention relates to the technical field of high-voltage signal testing and measuring, in particular to a high-voltage high-precision measuring device. Background In the prior art, with the improvement of the performance requirements of high-voltage direct current power supplies in the fields of new energy sources, semiconductors and the like, the requirements for high-precision measurement of kilovolt-level high voltage are increasing, and the measurement precision requirements are even improved to 7.5 positions. However, the current general measuring instrument is difficult to simultaneously consider the measurement precision and stability under high voltage and large dynamic range, and cannot meet the increasingly improved high-voltage and high-precision integrated test requirement. Disclosure of Invention Aiming at the problems of limited measurement voltage range, insufficient measurement precision and the like in the prior art, the disclosure provides a high-voltage and high-precision measurement circuit with a high-voltage direct-current protection function. The circuit adopts a core framework of combining a high-voltage attenuation resistor with differential input, so that the safe attenuation and input protection of kilovolt-level high-voltage signals are realized, common-mode interference is effectively restrained, the whole pressure resistance and anti-interference performance of the system are remarkably improved while the measurement range is widened, and the high-precision measurement requirement under a high-pressure environment is met. The core design idea is that a high-performance high-voltage attenuation resistor network is firstly arranged at the input end of a measuring circuit. The attenuation resistor network bears key current limiting and voltage dividing functions, can safely and linearly attenuate an input direct-current high-voltage signal with the voltage of thousands of volts to a low-voltage range which can be processed by a subsequent circuit according to a preset proportion, thereby constructing a first firm barrier on a physical layer, effectively avoiding high-voltage breakdown or overload risks and playing a vital protective role for a precise voltage measuring unit (such as a high-resolution analog-to-digital converter) at a later stage. The attenuated low voltage signal does not directly enter the measurement core unit, but is connected to the differential input unit. The unit adopts a symmetrical circuit architecture with high common mode rejection ratio, can identify and extract differential mode voltage signals (namely useful signals) between two input ends, and simultaneously greatly reject common mode noise (usually from ground wire loops, space electromagnetic coupling and the like) on the two input ends. The design greatly eliminates common mode interference superimposed on the signal line in a complex electromagnetic measurement environment, thereby ensuring the purity and the integrity of the measured voltage signal. Through the organic combination of the high-voltage attenuation protection and the differential noise suppression two-stage core technology, the voltage measurement range is safely expanded, the measurement precision and the system stability of signals are remarkably improved under the high-noise background, and the problem that the traditional method is difficult to consider at high voltage and high precision is fundamentally solved. Specifically, the high-voltage high-precision measuring device mainly comprises a high-voltage attenuation and input protection module, a high-voltage attenuation and input protection module and a high-precision measuring and processing module which are connected in sequence, wherein: The high-voltage attenuation and input protection module, the differential input and signal conditioning module and the high-precision measurement and processing module are connected in sequence, wherein: The high-voltage attenuation and input protection module is used for attenuating an input direct-current high-voltage signal to a low-voltage range which can be processed by a subsequent circuit according to a preset proportion; The differential input and signal conditioning module is used for identifying and extracting a differential mode voltage signal between two input ends, namely an effective signal, and simultaneously, greatly inhibiting common mode noise of the two input ends; the high-precision measuring and processing module converts the differential analog signal into a single-ended signal through pre-conditioning, then performs high-precision voltage measurement, performs analog-to-digital conversion, and finally uploads the signal to the processor through noise isolation. Further, the high voltage attenuation and input protection module comprises a resistor voltage division network and a rear end protection unit, wherein: the resistor voltage dividing network co