A high-precision voltage sensor

Abstract

This invention discloses a high-precision voltage sensor, relating to the field of intelligent detection and control. It aims to solve the problem that under high-voltage operating conditions, the sampled resistance power is relatively large, resulting in significant heat generation and thus affecting the sensor's measurement accuracy. The key technical solution involves electrically connecting the sensor's power output terminal to a high-frequency oscillation circuit, a microcontroller, and a linear signal output module. The microcontroller and the linear signal output module are electrically connected. The output terminal of the high-frequency oscillation circuit is electrically connected to a high-voltage precision-to-low-voltage conversion module, an amplified digital-to-analog conversion module, and a signal power amplification module. These modules are electrically connected, and the signal power amplification module is electrically connected to the microcontroller. This achieves the effect of improving the sensor's accuracy and enhancing its anti-interference capability.

Description

Technical Field

[0001] This invention relates to the field of intelligent detection and control technology, and in particular to a high-precision voltage sensor. Background Technology

[0002] In various electrical equipment and circuit control, it is necessary to accurately measure voltage and maintain voltage stability in the circuit. Voltage measurement requires the use of voltage sensors. In low voltage conditions, resistance measurement or resistance voltage divider measurement can be used to directly input the sampled voltage to the processing circuit for signal processing. For high voltage measurement, such as 2000V, 3000V, or even higher voltage values, not only is high-power resistance voltage divider sampling required during the measurement process, but high-voltage isolation is also required to ensure the safety and reliability of the circuit.

[0003] In high-voltage measurements, high-power, high-resistance resistors are typically used for voltage division, while low-resistance resistors are used for voltage sampling for signal analysis. Traditionally, the high-resistance resistors range from tens to hundreds of kiloohms. When the voltage is several hundred volts, the sampling current is several to tens of milliamps. Under normal conditions, this does not affect the operation of the main circuit or the current accuracy. However, in some applications requiring high precision, customers expect the sampling current to be as small as possible during voltage measurement. In addition, during sensor operation at high voltages, although the sampling current is only a few milliamps or tens of milliamps, the sampled voltage value is relatively high, reaching several kilovolts or even higher. This results in a large power consumption of the sampling resistor, causing significant heat generation and thus affecting the sensor's measurement accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision voltage sensor.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-precision voltage sensor includes a sensor power supply, a first power conversion circuit, a first electrical isolation module, a high-frequency oscillation circuit, a second power conversion circuit, a third power conversion circuit, a high-voltage precision-to-low-voltage conversion module, an amplification digital-to-analog conversion module, a signal power amplification module, a second electrical isolation module, a microcontroller, and a linear signal output module. The sensor power supply output is electrically connected to the high-frequency oscillation circuit, the microcontroller, and the linear signal output module; a second power conversion circuit is provided between the sensor power supply and the microcontroller; and a third power conversion circuit is provided between the sensor power supply and the linear signal output module. The circuit includes a microcontroller and a linear signal output module that are electrically connected. The output of the high-frequency oscillation circuit is electrically connected to a high-voltage precision-to-low-voltage conversion module, an amplification digital-to-analog conversion module, and a signal power amplification module. A first electrical isolation module and a first power conversion circuit are provided between the high-frequency oscillation circuit and the low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module. The high-voltage precision-to-low-voltage conversion module, the amplification digital-to-analog conversion module, and the signal power amplification module are electrically connected. The signal power amplification module is electrically connected to the microcontroller. A second electrical isolation module is provided between the signal power amplification module and the microcontroller.

[0007] The power supply for the sensor is the power supply for the voltage sensor, which is used to provide an external power source for the sensor to operate. Generally, the power supply is ±24V, ±15V, or ±12V, but it can also be a single power supply.

[0008] The first power conversion circuit provides a high-precision 5V power supply to the high-voltage precision to low-voltage conversion module, the amplification digital-to-analog conversion module, and the signal power amplification module;

[0009] The second power conversion circuit converts the power supply voltage to 3.3V via a DC-DC module to power the microcontroller.

[0010] The third power conversion circuit converts the power supply voltage to ±15V via a DC-DC module for use by subsequent conversion circuits.

[0011] The first electrical isolation module transmits the high-frequency signal to the secondary coil through a high-frequency transformer via a high-frequency oscillation circuit. The high-frequency coil transmits the oscillation waveform to the secondary coil, which, after rectification, filtering, and high-precision voltage regulation, forms a high-precision regulated voltage. At the same time, the isolation module achieves high-voltage isolation.

[0012] The second electrical isolation module transmits a 1-bit digital bitstream signal to the secondary coil through a high-frequency transformer. The high-frequency coil is used to accurately transmit signal data and provide high-voltage isolation.

[0013] The high-voltage precision to low-voltage conversion module divides the high voltage using a high-resistance, high-power precision resistor and samples the voltage using a low-impedance precision resistor, thus converting the high voltage into a relatively low voltage with high precision.

[0014] The amplified digital-to-analog converter module is used to ensure that the input signal of the digital-to-analog converter does not damage the digital-to-analog converter; the digital-to-analog converter converts analog quantities into 1-bit serial bit streams, and 16-bit resolution is selected to ensure accuracy;

[0015] The signal power amplification module is a signal amplification circuit. The microcontroller converts the input signal from the digital-to-analog converter into a pulse-width modulated waveform through data processing and logic judgment.

[0016] The linear signal output module is used to rectify and filter the pulse output waveform into a linear output voltage that varies with the input signal. Alternatively, it can form a current output signal that varies with the input signal through a BTL (bridged load) complementary symmetrical power amplifier circuit driven by an operational amplifier.

[0017] The high-frequency oscillation circuit uses a classic voltage-type PWM controller to generate a set high-frequency oscillation circuit, which drives a high-frequency transformer and generates a stable operating voltage through electrical isolation 1 and a low dropout (LDO) linear regulator.

[0018] By adopting the above technical solution, through digital processing by digital-to-analog converter and data analysis and processing by microcontroller, precise data transmission of sampled voltage is achieved, safe electrical isolation between high voltage and low voltage signals is realized, and safe transmission of voltage acquisition and precise transmission of voltage value are completed.

[0019] Furthermore, the first power conversion circuit includes a diode D1, an electrolytic capacitor C5, a ceramic capacitor C9, a dual-channel isolated DC-DC power module PS2, a filter capacitor C18, a filter capacitor C21, a filter capacitor C17, and a filter capacitor C20.

[0020] Furthermore, one end of diode D1 is connected to a +24V power supply. The other end of diode D1, one end of electrolytic capacitor C5, one end of ceramic capacitor C9, and pin 1 of the dual-channel isolated DC-DC power module PS2 are electrically connected. The other end of electrolytic capacitor C5, the other end of ceramic capacitor C9, and pin 2 of the dual-channel isolated DC-DC power module PS2 are electrically connected to a -24V power supply. Pin 4 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C17, and one end of filter capacitor C20 are electrically connected. The other end of capacitor C17 and the other end of filter capacitor C20 are grounded respectively. Pin 5 of the dual-channel isolated DC-DC power module PS2 is grounded. Pin 4 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C17 and one end of filter capacitor C20 output -15V power. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18 and one end of filter capacitor C21 are electrically connected. The other end of filter capacitor C18 and the other end of filter capacitor C21 are grounded respectively. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18 and one end of filter capacitor C21 output +15V power.

[0021] Furthermore, the second power conversion circuit includes a diode D2, an electrolytic capacitor C4, a ceramic capacitor C8, a single-channel isolated DC-DC power module PS1, a filter capacitor C16, a filter capacitor C19, and a voltage regulator U3.

[0022] Furthermore, one end of diode D2 is connected to a +24V power supply. The other end of diode D2, one end of electrolytic capacitor C4, one end of ceramic capacitor C8, and pin 2 of single-channel isolated DC-DC power module PS1 are electrically connected. The other end of electrolytic capacitor C4, the other end of ceramic capacitor C8, and pin 1 of single-channel isolated DC-DC power module PS1 are electrically connected to a -24V power supply. Pin 6 of single-channel isolated DC-DC power module PS1, one end of filter capacitor C16, one end of filter capacitor C19, and pin 3 of voltage regulator U3 are electrically connected. Pin 7 of single-channel isolated DC-DC power module PS1 is grounded. Pin 6 of single-channel isolated DC-DC power module PS1 outputs 5V power. The other ends of filter capacitor C16 and filter capacitor C19 are grounded respectively. Pin 1 of voltage regulator U3 is grounded. Pin 2 of voltage regulator U3 outputs 3.3V power.

[0023] Furthermore, the third power conversion circuit includes a high-frequency isolation signal transformer T2, ceramic capacitors C42 and C43, isolation capacitor C41, Schottky diodes D5 and D6, filter capacitors C36 and C38, a high-precision power regulator chip U11, resistors R33 and R34, and filter capacitors C33 and C34.

[0024] Furthermore, pin 4 of the high-frequency isolation signal transformer T2 is connected to the high-frequency signal T1-A, pin 3 of the high-frequency isolation signal transformer T2 is connected to the high-frequency signal T1-B, pin 1 of the high-frequency isolation signal transformer T2, one end of the ceramic capacitor C43, and pin 3 of the Schottky diode D6 are electrically connected, pin 1 of the Schottky diode D6 is grounded, pin 2 of the high-frequency isolation signal transformer T2, one end of the ceramic capacitor C42, and one end of the isolation capacitor C41 are electrically connected, the other end of the ceramic capacitor C42 is grounded, the other end of the isolation capacitor C41 is electrically connected to pin 3 of the Schottky diode D5, pin 1 of the Schottky diode D5 is grounded, and pins 2 of the Schottky diode D5, pin 2 of the Schottky diode D6, and the filter capacitor are connected... One end of capacitor C38, one end of filter capacitor C36, pin 1 of high-precision power regulator chip U11, and pin 3 of high-precision power regulator chip U11 are electrically connected. The other ends of filter capacitor C38 and filter capacitor C36 are grounded respectively. Pin 2 of high-precision power regulator chip U11 is grounded. Pin 5 of high-precision power regulator chip U11 is electrically connected to one end of resistor R34. The other end of resistor R34, one end of filter capacitor C34, and one end of resistor R33 are electrically connected. The other end of filter capacitor C34 is grounded. The other end of resistor R33 is connected to one end of filter capacitor C33. The other end of filter capacitor C33 is grounded. The other end of resistor R33 is connected to the output 5V2 power supply of filter capacitor C33.

[0025] By adopting the above technical solution, the power input is ±24V (48V). One path passes through polarized diode D1, filter capacitors C5 and C9, then through PS2 power conversion, and after passing through filter capacitors C18, C21, C17, and C20, outputs a stable +15V and -15V. The other path passes through polarized diode D2, filter capacitors C4 and C8, then through PS1 power conversion, and after passing through filter capacitors C16 and C19, outputs a stable +5V. After passing through the precision voltage regulator circuit U3, the voltage is converted to 3.3V. The third power supply isolates the high-frequency voltage signal through T2 for electrical isolation. After filtering by C42 and C43 and DC isolation by C41, it is rectified into a DC signal by dual diodes D5 and D6. After voltage filtering, it is input to the high-precision voltage regulator chip U11. After passing through resistor R34 and filter capacitor C34, it outputs a high-precision and stable 5V power supply (5V1) as the working power supply for the core components. Then, through a small-value resistor R33 and filter capacitor C33, it outputs a 5V power supply (5V2) as the high-level input voltage in the circuit.

[0026] Furthermore, the high-voltage precision conversion low-voltage module internally includes a high-voltage resistor R9, a high-voltage resistor R12, a voltage divider resistor R10, a voltage divider resistor R11, a filter capacitor C24, a filter capacitor C25, a current-limiting resistor R17, a current-limiting resistor R18, and a differential capacitor C27. One end of the high-voltage resistor R9 is connected to a 2000V+ voltage, and one end of the high-voltage resistor R12 is connected to a 2000V- voltage. The other end of the high-voltage resistor R9, one end of the voltage divider resistor R10, one end of the filter capacitor C24, and one end of the current-limiting resistor R17 are electrically connected. The other end of the filter capacitor C24 is grounded. The other end of resistor R12, one end of voltage divider resistor R11, one end of filter capacitor C25, and one end of current limiting resistor R18 are electrically connected. The other end of filter capacitor C25 is grounded. The other end of voltage divider resistor R11 and the other end of voltage divider resistor R10 are electrically connected. The other end of current limiting resistor R17 and one end of differential capacitor C27 are electrically connected. The other end of current limiting resistor R17 and one end of differential capacitor C27 output Vin+. The other end of current limiting resistor R18 and the other end of differential capacitor C27 are electrically connected. The other end of current limiting resistor R18 and the other end of differential capacitor C27 output Vin-.

[0027] By adopting the above technical solution, the 2000V+ and 2000V- high voltage inputs are divided by four series high-impedance resistors R9, R10, R11, and R12, and differential low voltage signals are extracted at the upper and lower nodes of R10 and R11. C24 and C25 perform common-mode filtering on the upper and lower nodes respectively to suppress common-mode interference and surge spikes on the high voltage side. R17 and R18 provide current-limiting protection for the differential signal, and together with C27, they form an RC low-pass filter to filter out differential high-frequency noise. Finally, stable and clean mV-level differential signals Vin+ and Vin- are output and sent to the subsequent amplification and digital-to-analog conversion module to achieve accurate sampling and digital conversion of the high voltage signal.

[0028] Furthermore, the amplified digital-to-analog converter module internally includes operational amplifier U9, operational amplifier U10, Zener diode U8, resistor R24, feedback resistor R27, feedback resistor R28, feedback capacitor C31, feedback capacitor C32, output resistor R31, output resistor R32, dual diode D3, digital converter U12, current-limiting resistor R35, filter capacitor C39, filter capacitor C40, filter capacitor C35, filter capacitor C37, current-limiting resistor R36, dual diode D4, and current-limiting resistor R37. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are electrically connected. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are connected to Vin+. Pin 4 of operational amplifier U9, one end of resistor R24, and one end of Zener diode U8 are electrically connected. The other end is grounded. The other end of the resistor R24 ​​is connected to a 5V power supply. The other end of the feedback capacitor C31, the other end of the feedback resistor R27, pin 1 of the operational amplifier U9, and one end of the output resistor R31 are electrically connected. One end of the operational amplifier U9 is grounded. The other end of the output resistor R31 is electrically connected to pin 2 of the digital converter U12. Pin 3 of the operational amplifier U10, one end of the feedback capacitor C32, and one end of the feedback resistor R28 are electrically connected. Pin 3 of the operational amplifier U10, one end of the feedback capacitor C32, and one end of the feedback resistor R28 are connected to Vin-. One end of the operational amplifier U10 is grounded. The other end of the feedback capacitor C32, the other end of the feedback resistor R28, pin 1 of the operational amplifier U10, and one end of the output resistor R32 are electrically connected. The other end of the output resistor R32 is electrically connected to pin 3 of the digital converter U12.

[0029] Pin 16 of the digital converter U12 is grounded, pins 7 and 8 of the digital converter U12 are grounded, pin 5 of the digital converter U12 is electrically connected to the first segment of the current limiting resistor R35, the other end of the current limiting resistor R35 is electrically connected to pin 3 of the dual diode D3, the other end of the current limiting resistor R35 and pin 3 of the dual diode D3 are connected to power supply 5V1, and pin 2 of the dual diode D3 is connected to power supply 5V2.

[0030] The digital converter U12 has its pin 13, one end of the current-limiting resistor R36, one end of the filter capacitor C35, and one end of the filter capacitor C37 electrically connected. The other ends of the filter capacitors C35 and C37 are grounded. The other end of the current-limiting resistor R36 is connected to a 5V1 power supply. The digital converter U12 has its pin 12, one end of the filter capacitor C39, and one end of the filter capacitor C40 electrically connected. The other ends of the filter capacitors C39 and C40 are grounded. The digital converter U12 has its pin 9, one end of the current-limiting resistor R37 electrically connected to pin 3 of the dual diode D4. Pin 1 of the dual diode D4 is grounded. One end of the dual diode D4 is connected to a 5V1 power supply. The other end of the current-limiting resistor R37 and pin 3 of the dual diode D4 output a 16-bit digital bitstream Vdat1.

[0031] By adopting the above technical solution, the Vin+ and Vin- differential weak signals output by the high-voltage divider module are input to operational amplifiers U9 and U10, respectively. After active filtering and buffer amplification, a stable analog differential signal is output. The amplified signal is then current-limited by R31 and R32 and input to the differential input terminal of the digital-to-analog converter U12. Under a stable 5V1 power supply and reference voltage, U12 converts the analog signal into a 16-bit digital bit stream Vdat1. The digital signal is then current-limited by R37 and clamped by D4 before being output and sent to the subsequent isolation driver module. This achieves high-precision and high-reliability conversion between analog and digital signals, providing accurate digital input for subsequent microcontroller processing.

[0032] Furthermore, the microcontroller internally includes a passive crystal oscillator Y1, oscillation capacitors C1 and C2, a load resistor R3, a pull-up resistor R4, a filter capacitor C7, pin headers J1 and J2, a resistor R1, a microcontroller U2, decoupling capacitors C12, C13, and C14. Pin 4 of the microcontroller U2, one end of the filter capacitor C7, and one end of the pull-up resistor R4 are electrically connected. The other end of the filter capacitor C7 is grounded. The other end of resistor R4 is connected to a 3.3V power supply. Pin 31 of the microcontroller U2 is electrically connected to pin 2 of pin header J1. Pin 1 of pin header J1 is connected to a 3.3V power supply. Pin 3 of pin header J1 is electrically connected to one end of resistor R1. The other end of resistor R1 is grounded. Pin 2 of the microcontroller U2, one end of the load resistor R3, one end of the oscillation capacitor C1, and pin 3 of the passive crystal oscillator Y1 are electrically connected. Pin 3 of the microcontroller U2, the other end of the load resistor R3, ... One end of the starting capacitor C2 at pin 1 of the passive crystal oscillator Y1 is electrically connected. The other ends of the starting capacitor C2 and C1 are electrically connected to pin 2 of the passive crystal oscillator Y1. The other ends of the starting capacitor C2 and C1 are grounded to pin 2 of the passive crystal oscillator Y1. Pin 4 of the passive crystal oscillator Y1 is grounded. Pins 16 and 32 of the microcontroller U2 are grounded respectively. Pin 20 of the microcontroller U2 is electrically connected to pin 2 of the header J2. Pin 21 of microcontroller U2 is electrically connected to pin 3 of pin header J2. Pin 1 of pin header J2 is connected to a 3.3V power supply, and pin 4 of pin header J2 is grounded. Pin 1, pin 17, pin 5 of microcontroller U2, one end of decoupling capacitor C12, one end of decoupling capacitor C13, and one end of decoupling capacitor C14 are electrically connected. The other ends of decoupling capacitors C12, C13, and C14 are grounded respectively.

[0033] By adopting the above technical solution, C12 / C13 / C14 external to the microcontroller U2 are power supply decoupling capacitors, located near the VDD / VDDA pins, to filter out power supply ripple and suppress interference; resistor R4 and capacitor C7 form a power-on reset circuit; J1 is an optional debug / startup mode switching interface, with a high level for download mode and a low level for normal operation mode; J2 is the program download port and parameter debugging interface, connected to the PA9, PA10, PA11, and PA12 pins of the microcontroller U2 for program download and debugging; oscillation resistor R3, oscillation capacitors C1 and C2, and crystal oscillator Y1 form the external oscillation input of the microcontroller, connected to the PF0 and PF1 pins of U2 to provide the system clock for the microcontroller; pin 9 of the microcontroller is the signal input port PA3, and pin 24 is the microcontroller output port U3-OUT.

[0034] Furthermore, the signal power amplification module internally includes a NAND gate driver circuit U1, filter capacitors C6 and C10, current-limiting resistors R2, C3, R6, and C15, a DC blocking capacitor C11, a resistor R5, and a high-frequency dual-coil T1. Pin 1 of the NAND gate driver circuit U1 is electrically connected to one end of resistor R5, and the other end of resistor R5 is grounded. Pin 2 of the NAND gate driver circuit U1 is connected to Vdat1. Pin 3 of the NAND gate driver circuit U1 is electrically connected to one end of current-limiting resistor R6. The other end of current-limiting resistor R6, one end of filter capacitor C15, and pin 2 of the high-frequency dual-coil T1 are electrically connected. Pin 4 of the NAND gate driver circuit U1 is grounded. Pin 1 of the high-frequency dual-coil T1 is electrically connected to one end of DC blocking capacitor C11. The other end of the DC blocking capacitor C11, one end of the filter capacitor C3, and one end of the current limiting resistor R2 are electrically connected. The other end of the current limiting resistor R2 is electrically connected to pin 7 of the NAND gate driver circuit U1. The other end of the filter capacitor C3 is grounded. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are electrically connected. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are connected to a 5V1 power supply. The other ends of the filter capacitor C6 and the other ends of the filter capacitor C10 are grounded respectively. Pin 5 of the NAND gate driver circuit U1 is connected to Vdat1. Pin 6 of the NAND gate driver circuit U1 is connected to 5V2. Pin 3 of the high-frequency dual-group coil T1 is grounded. Pin 4 of the high-frequency dual-group coil T1 outputs PA3.

[0035] Furthermore, the high-frequency oscillation circuit internally includes a controller chip U5, a decoupling capacitor C29, a soft-start capacitor C26, a timing resistor R13, a decoupling capacitor C22, a timing capacitor C23, a current-limiting resistor R20, a resistor R22, an external high-frequency transformer T1-A, an external high-frequency transformer T1-B, and a power switch Q1. Pins 13 and 15 of the controller chip U5 are electrically connected to one end of the decoupling capacitor C29. Pins 13 and 15 of the controller chip U5 and one end of the decoupling capacitor C29 are connected to a 5V power supply, and the other end of the decoupling capacitor C29 is grounded. Pin 16 of the controller chip U5, one end of the timing resistor R13, and one end of the decoupling capacitor C22 are electrically connected, and the other end of the timing resistor R13 is electrically connected to pin 6 of the controller chip U5. The other end of the decoupling capacitor C22 is grounded. Pin 10 of the controller chip U5 is grounded. Pins 5 and 7 of the controller chip U5 are electrically connected to one end of the timing capacitor C23, and the other end of the timing capacitor C23 is grounded. Pin 8 of the controller chip U5 is electrically connected to one end of the soft-start capacitor C26, and the other end of the soft-start capacitor C26 is grounded. Pin 14 of the controller chip U5 outputs a drive for an external high-frequency transformer T1-B. Pin 11 of the controller chip U5 is electrically connected to one end of the current-limiting resistor R20. The other end of the current-limiting resistor R20 is electrically connected to pin 1 of the power switch Q1. Pin 2 of the power switch Q1 is electrically connected to resistor R22, and the other end of the resistor R22 is grounded. Pin 3 of the power switch Q1 outputs a drive for an external high-frequency transformer T1-A.

[0036] Furthermore, the linear signal output module internally includes a single power supply U4, a current-limiting resistor R8, a pull-up resistor R14, a pull-up resistor R19, an optocoupler U6, a pull-up resistor R16, a decoupling capacitor C28, a current-limiting resistor R21, a filter capacitor C30, a feedback resistor R26, a feedback resistor R23, a load resistor R29, operational amplifiers U7A and U7B, an op-amp input resistor R25, and an op-amp feedback resistor R30. Pin 6 of the single power supply U4, one end of the pull-up resistor R14, and one end of the current-limiting resistor R8 are electrically connected. The other end of the pull-up resistor R14 is connected to a 5V power supply, the other end of the current-limiting resistor R8 is connected to the U3-OUT signal, pin 3 of the single power supply U4 is grounded, pin 5 of the single power supply U4 is connected to a 5V power supply, pin 2 of the single power supply U4 is grounded, pin 1 of the single power supply U4, one end of the pull-up resistor R19, and one end of the optocoupler U6 are electrically connected, the other end of the pull-up resistor R19 is connected to a 5V power supply, the other end of the optocoupler U6 is grounded, and pin 4 of the single power supply U4 is electrically connected to one end of the pull-up resistor R16. The other end of the pull-up resistor R16, one end of the decoupling capacitor C28, and one end of the current-limiting resistor R21 are electrically connected. The other end of the decoupling capacitor C28 is electrically connected. The other end of the current-limiting resistor R21, one end of the filter capacitor C30, and pin 3 of the operational amplifier U7A are electrically connected. The other end of the filter capacitor C30 is grounded. Pins 1 and 2 of the operational amplifier U7A and one end of the op-amp input resistor R25 are electrically connected. The other end of the op-amp input resistor R25, one end of the feedback resistor R26, and the operational amplifier U7A are electrically connected. Pin 6 of operational amplifier U7B is electrically connected. The other end of feedback resistor R26, one end of feedback resistor R23, and one end of load resistor R29 are electrically connected. The other end of feedback resistor R23 is connected to a +15V power supply, and the other end of load resistor R29 is connected to a -15V power supply. Pin 5 of operational amplifier U7B is electrically connected to one end of operational amplifier feedback resistor R30. The other end of operational amplifier feedback resistor R30 is electrically connected to pin 7 of operational amplifier U7B. The other end of operational amplifier feedback resistor R30 is connected to the output Vout of pin 7 of operational amplifier U7B.

[0037] By adopting the above technical solution, U4 is a single-supply, bidirectional, SPDT (single-pole double-throw) analog switch that performs threshold judgment, channel switching, and level clamping protection on the input U3-OUT signal. It is commonly used in scenarios such as signal isolation, zero-crossing detection, and multi-channel signal selection. R8 is an input current-limiting resistor that limits the input current of U3-OUT and protects the Vin pin of U4 from overcurrent damage. R14 is a pull-up resistor that pulls the Vin pin potential up to 5V, which, together with the input signal, enables high and low level judgment and ensures reliable switching. R19 and U6 form a voltage regulator circuit, providing a reliable and stable internal reference voltage. R16, C28, R21, and C30 form a second-order RC low-pass filter circuit that filters out high-frequency noise and spike interference in the input signal, smooths the waveform, and retains useful low-frequency / The circuit filters and rectifies the pulse signal into a DC signal for the power frequency signal; U7 is a dual operational amplifier that amplifies the input signal and outputs it; R26, R23, and R29 form a reference voltage for the op-amp input; R25 is the op-amp input resistor; and R30 is the op-amp feedback resistor.

[0038] In summary, the beneficial technical effects of the present invention are as follows:

[0039] 1. An amplified digital-to-analog converter module is used to amplify and digitize the weak input analog signal, converting the analog quantity into a high-precision digital signal before sending it to the microcontroller for analysis and calculation. This effectively improves the accuracy and stability of voltage sampling, enables high-voltage input detection, and the output signal has a good linear correspondence with the input voltage.

[0040] 2. A high-voltage divider circuit is constructed using high-resistance, high-voltage-resistant resistors, which significantly reduces the sampling current, reduces the impact on the measured main circuit current, reduces power loss and heat generation, and improves measurement accuracy. A combination of high-voltage divider, analog-to-digital conversion, and microcontroller processing is adopted to ensure high sensor output accuracy and good linearity.

[0041] 3. A high-frequency isolation transformer is used to achieve high-voltage electrical isolation between the input and output terminals, ensuring system safety and reliability. Two isolation transformers are used to achieve high isolation on the power supply side and high isolation on the data signal side, respectively, improving system safety and anti-interference ability. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the workflow logic of the present invention;

[0043] Figure 2 This is a schematic diagram of the first power conversion circuit of the present invention;

[0044] Figure 3 This is a schematic diagram of the second power conversion circuit of the present invention;

[0045] Figure 4 This is a schematic diagram of the third power conversion circuit of the present invention;

[0046] Figure 5 This is a schematic diagram of the high-voltage precision conversion low-voltage module circuit of this invention;

[0047] Figure 6 This is a schematic diagram of the amplified digital-to-analog converter module circuit of the present invention;

[0048] Figure 7 This is a schematic diagram of the microcontroller circuit of the present invention;

[0049] Figure 8 This is a schematic diagram of the signal power amplifier circuit of the present invention;

[0050] Figure 9 This is a schematic diagram of the high-frequency oscillation circuit of the present invention;

[0051] Figure 10 This is a schematic diagram of the linear signal output module circuit of the present invention. Detailed Implementation

[0052] The method of the present invention will be further described in detail below with reference to the accompanying drawings.

[0053] See attached document Figure 1 A high-precision voltage sensor includes a sensor power supply, a first power conversion circuit, a first electrical isolation module, a high-frequency oscillation circuit, a second power conversion circuit, a third power conversion circuit, a high-voltage precision-to-low-voltage module, an amplification digital-to-analog conversion module, a signal power amplification module, a second electrical isolation module, a microcontroller, and a linear signal output module. The sensor power supply output is electrically connected to the high-frequency oscillation circuit, the microcontroller, and the linear signal output module. A second power conversion circuit is provided between the sensor power supply and the microcontroller. A third power conversion circuit is provided between the sensor power supply and the linear signal output module. The microcontroller and the linear signal output module are electrically connected. The high-frequency oscillation circuit output is electrically connected to the high-voltage precision-to-low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module. A first electrical isolation module and a first power conversion circuit are provided between the high-frequency oscillation circuit and the low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module. The high-voltage precision-to-low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module are electrically connected. The signal power amplification module is electrically connected to the microcontroller. A second electrical isolation module is provided between the signal power amplification module and the microcontroller.

[0054] The sensor power supply is the power supply for the voltage sensor, which is used to provide the external power supply for the sensor to work. Generally, the power supply is a dual power supply of ±24V, ±15V, and ±12V, but it can also be a single power supply.

[0055] The first power conversion circuit provides a high-precision 5V power supply to the high-voltage precision to low-voltage conversion module, the amplification digital-to-analog conversion module, and the signal power amplification module.

[0056] The second power conversion circuit converts the power supply voltage to 3.3V via a DC-DC module to power the microcontroller.

[0057] The third power conversion circuit converts the power supply voltage to ±15V via a DC-DC module for use by subsequent conversion circuits.

[0058] The first electrical isolation module uses a high-frequency oscillation circuit to transmit the high-frequency signal to the secondary coil via a high-frequency transformer. The high-frequency coil transmits the oscillation waveform to the secondary coil, which then undergoes rectification, filtering, and high-precision voltage regulation to form a high-precision regulated voltage, ensuring the conversion accuracy of the digital-to-analog converter. At the same time, this isolation module achieves high-voltage isolation.

[0059] The second electrical isolation module transmits a 1-bit digital bitstream signal to the secondary coil through a high-frequency transformer. The high-frequency coil is used to transmit signal data and provide high-voltage isolation.

[0060] The high-voltage precision conversion low-voltage module divides the high voltage using a high-resistance, high-power resistor and samples the voltage using a low-impedance resistor, converting the high voltage into a relatively low voltage.

[0061] The amplification module for the digital-to-analog converter (DAC) ensures that the input signal to the DAC does not damage it. The DAC converts analog signals into a 1-bit serial bit stream; to ensure the accuracy of the DAC conversion, a 16-bit resolution is selected.

[0062] The signal power amplification module is a signal amplification circuit. The microcontroller converts the input signal from the digital-to-analog converter into a pulse-width modulated waveform through data processing and logic judgment.

[0063] The linear signal output module is used to rectify and filter the pulse output waveform into a linear output voltage that varies with the input signal. Alternatively, it can form a current output signal that varies with the input signal through a BTL (bridged load) complementary symmetrical power amplifier circuit driven by an operational amplifier.

[0064] The high-frequency oscillation circuit uses a classic voltage-type PWM controller to generate a set high-frequency oscillation circuit, which drives a high-frequency transformer and generates a stable operating voltage through an electrical isolation 1 and a low dropout (LDO) linear regulator.

[0065] Reference Figure 2The first power conversion circuit includes a high-frequency isolation signal transformer T2, ceramic capacitors C42 and C43, an isolation capacitor C41, Schottky diodes D5 and D6, filter capacitors C36 and C38, a high-precision power regulator chip U11, resistors R33 and R34, and filter capacitors C33 and C34. Pin 4 of the high-frequency isolation signal transformer T2 is connected to the high-frequency signal T1-A, and pin 3 of the high-frequency isolation signal transformer T2 is connected to the high-frequency signal T1-B. Pin 1 of the high-frequency isolation signal transformer T2, one end of ceramic capacitor C43, and pin 3 of Schottky diode D6 are electrically connected. Pin 1 of Schottky diode D6 is grounded. Pin 2 of the high-frequency isolation signal transformer T2, one end of ceramic capacitor C42, and one end of isolation capacitor C41 are electrically connected. The other end of ceramic capacitor C42 is grounded. The other end of isolation capacitor C41 is electrically connected to pin 3 of Schottky diode D5. Pin 1 of Schottky diode D5 is grounded. Pins 2 of Schottky diode D5 and D6, one end of filter capacitor C38, one end of filter capacitor C36, pins 1 and 3 of high-precision power regulator chip U11 are electrically connected. The other ends of filter capacitors C38 and C36 are grounded. Pin 2 of high-precision power regulator chip U11 is grounded. Pin 5 of high-precision power regulator chip U11 is electrically connected to one end of resistor R34. The other end of resistor R34, one end of filter capacitor C34, and one end of resistor R33 are electrically connected to one end of resistor R33. The other end of filter capacitor C34 is grounded. The other end of resistor R33 is connected to one end of filter capacitor C33. The other end of filter capacitor C33 is grounded. The other end of resistor R33 is connected to the output 5V2 power supply of filter capacitor C33. T2 (high-frequency isolation signal transformer) is used for electrical isolation and signal coupling. Primary side 4-3 Pins (T1-A / T1-B), pins 1-2 on the secondary side, achieve complete signal isolation; C42 / C43 (ceramic capacitors), high-frequency filtering on the primary side, suppressing common-mode interference and optimizing transformer waveform; C41, DC blocking coupling, prevents transformer DC bias saturation; D5 / D6 (Schottky diodes), full-wave rectification, rectifying the high-frequency AC signal on the transformer secondary side into DC, fast switching speed, suitable for high-frequency rectification; C36 / C38, after rectification, combined filtering to obtain a smooth DC voltage, sent to LDO input; U11 is the core LDO, fixed 5V output, low dropout voltage, low noise, designed specifically for precision analog circuits, perfectly adapted to digital-to-analog converter circuits; R33 / R34 output current limiting / damping, suppressing output oscillation and protecting the LDO; C34 is LDO output filtering, C5 is final output filtering, ensuring clean and stable 5V output.

[0066] Reference Figure 3The second power conversion circuit includes a diode D2, an electrolytic capacitor C4, a ceramic capacitor C8, a single-channel isolated DC-DC power module PS1, filter capacitors C16 and C19, and a voltage regulator U3. One end of diode D2 is connected to a +24V power supply. The other end of diode D2, one end of electrolytic capacitor C4, one end of ceramic capacitor C8, and pin 2 of the single-channel isolated DC-DC power module PS1 are electrically connected. The other end of electrolytic capacitor C4 and the other end of ceramic capacitor C8 are electrically connected to pin 1 of the single-channel isolated DC-DC power module PS1. The other end of electrolytic capacitor C4 and the other end of ceramic capacitor C8 are electrically connected to pin 1 of the single-channel isolated DC-DC power module PS1. The other end of capacitor C8 and pin 1 of the single-channel isolated DC-DC power module PS1 are connected to a -24V power supply. Pin 6 of the single-channel isolated DC-DC power module PS1, one end of filter capacitor C16, one end of filter capacitor C19, and pin 3 of voltage regulator U3 are electrically connected. Pin 7 of the single-channel isolated DC-DC power module PS1 is grounded. Pin 6 of the single-channel isolated DC-DC power module PS1 outputs 5V power. The other ends of filter capacitors C16 and C19 are grounded respectively. Pin 1 of voltage regulator U3 is grounded. Pin 2 of voltage regulator U3 outputs 3.3V power. D2 (diode) Reverse connection protection to prevent +24V / -24V from being reversed and burning out the module; 1N5819 / 1N4007 is recommended, with a withstand voltage ≥50V and a current ≥1A; C4 (electrolytic capacitor) is used for low-frequency input filtering to remove low-frequency power supply ripple; 10μF / 50V is recommended, with sufficient voltage margin, and placed close to the module pins; C8 (ceramic capacitor) is used for high-frequency input filtering to remove high-frequency interference; 0.1μF / 50V X7R material is recommended, forming a combined filter with the electrolytic capacitor; PS1 (single-channel isolated DC-DC power supply module), such as ±24V input and 5V output, has built-in isolation to achieve complete input and output ground isolation, completely blocking interference crosstalk; C16 / C19 (5V filter) filters out 5V output ripple, and the combined filter covers high and low frequencies, placed close to the module pins; U3 (LDO regulator) converts 5V to 3.3V. For step-down converters, recommended models include: AMS1117-3.3 (general purpose), LP2985-3.3 (low noise, compatible with ADC), XC6206-3.3 (low power consumption), etc.; GND1 (isolation ground) is an independent ground on the output side, completely isolated from the input ground. It is forbidden to share a ground with the input ground, otherwise the isolation will be meaningless.

[0067] Reference Figure 4The third power conversion circuit includes diode D1, electrolytic capacitor C5, ceramic capacitor C9, dual-channel isolated DC-DC power module PS2, filter capacitors C18, C21, C17, and C20. One end of diode D1 is connected to a +24V power supply. The other end of diode D1, one end of electrolytic capacitor C5, one end of ceramic capacitor C9, and pin 1 of dual-channel isolated DC-DC power module PS2 are electrically connected. The other ends of electrolytic capacitor C5 and ceramic capacitor C9 are electrically connected to pin 2 of dual-channel isolated DC-DC power module PS2. The other ends of electrolytic capacitor C5 and ceramic capacitor C9, and pin 2 of dual-channel isolated DC-DC power module PS2 are connected to a -24V power supply. Pin 4 of S2, one end of filter capacitor C17, and one end of filter capacitor C20 are electrically connected. The other ends of filter capacitors C17 and C20 are grounded. Pin 5 of the dual-channel isolated DC-DC power module PS2 is grounded. Pin 4 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C17, and one end of filter capacitor C20 output -15V power. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18, and one end of filter capacitor C21 are electrically connected. The other ends of filter capacitors C18 and C21 are grounded. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18, and one end of filter capacitor C21 output +15V power. D1 (diode). Reverse connection protection to prevent +24V / -24V from being reversed and burning out the module; 1N5819 / 1N4007 is recommended, with a withstand voltage ≥50V; C5 (electrolytic capacitor), a large input capacitor for filtering, to remove low-frequency ripple; 10μF / 50V is recommended, with a voltage margin; C9 (ceramic capacitor), a high-frequency input filter to remove high-frequency interference; 0.1μF / 50V, X7R material is recommended, placed close to the module pins; PS2 (dual-channel isolated DC-DC power supply module), such as input ±24V, output ±15V, etc., with built-in isolation, achieving complete isolation between input and output grounds, completely blocking interference crosstalk; C18 / C21 (+15V filter) and C17 / C20 (-15V filter), combined filtering, covering high and low frequencies; GND1 (isolation ground), an independent ground on the output side, completely isolated from the input ground; sharing a ground is prohibited, otherwise the isolation is meaningless.

[0068] Reference Figure 5The high-voltage precision conversion module for low-voltage conversion includes high-voltage resistor R9, high-voltage resistor R12, voltage divider resistors R10 and R11, filter capacitor C24 and C25, current-limiting resistor R17 and R18, and differential capacitor C27. One end of high-voltage resistor R9 is connected to 2000V+, and one end of high-voltage resistor R12 is connected to 2000V-. The other end of high-voltage resistor R9, one end of voltage divider resistor R10, one end of filter capacitor C24, and one end of current-limiting resistor R17 are electrically connected. The other end of filter capacitor C24 is grounded. The other end of high-voltage resistor R12... One end of the voltage divider resistor R11, one end of the filter capacitor C25, and one end of the current limiting resistor R18 are electrically connected. The other end of the filter capacitor C25 is grounded. The other end of the voltage divider resistor R11 and the other end of the voltage divider resistor R10 are electrically connected. The other end of the current limiting resistor R17 and one end of the differential capacitor C27 are electrically connected, and the output of the other end of the current limiting resistor R17 and one end of the differential capacitor C27 is Vin+. The other end of the current limiting resistor R18 and the other end of the differential capacitor C27 are electrically connected, and the output of the other end of the current limiting resistor R18 and the other end of the differential capacitor C27 is Vin-. R9 / R12 (upper / lower) The high-voltage series resistors (R10 / R11) are used for voltage division. High-voltage, high-resistance resistors are required to withstand the total 2000V voltage after series connection, achieving high voltage reduction. The intermediate voltage divider resistors (R10 / R11 and R9 / R12) form a voltage divider ratio at the sampling node, reducing the 2000V voltage to tens of mV. C24 / C25 are common-mode filters / surge suppressors, filtering out common-mode interference from the high-voltage side and improving anti-interference capability. R17 / R18 are current-limiting resistors, used for current limiting / impedance matching, limiting the current flowing into the ADC, protecting the digital-to-analog converter, and simultaneously forming an RC filter network. C27 is a differential capacitor, filtering out high-frequency interference from the differential signal and optimizing the sampling waveform.

[0069] Reference Figure 6The amplification digital-to-analog converter module internally includes operational amplifier U9, operational amplifier U10, Zener diode U8, resistor R24, feedback resistor R27, feedback resistor R28, feedback capacitor C31, feedback capacitor C32, output resistor R31, output resistor R32, dual diode D3, digital converter U12, current-limiting resistor R35, filter capacitor C39, filter capacitor C40, filter capacitor C35, filter capacitor C37, current-limiting resistor R36, dual diode D4, and current-limiting resistor R37. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are electrically connected. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are connected to Vin+. Pin 4 of operational amplifier U9, one end of resistor R24, and one end of Zener diode U8 are electrically connected. The other end of 8 is grounded, the other end of resistor R24 ​​is connected to the 5V power supply, the other end of feedback capacitor C31, the other end of feedback resistor R27, pin 1 of operational amplifier U9 and one end of output resistor R31 are electrically connected, one end of operational amplifier U9 is grounded, the other end of output resistor R31 is electrically connected to pin 2 of digital converter U12, pin 3 of operational amplifier U10, one end of feedback capacitor C32 and one end of feedback resistor R28 are electrically connected, pin 3 of operational amplifier U10, one end of feedback capacitor C32 and one end of feedback resistor R28 are connected to Vin-, one end of operational amplifier U10 is grounded, the other end of feedback capacitor C32, the other end of feedback resistor R28, pin 1 of operational amplifier U10 and one end of output resistor R32 are electrically connected, the other end of output resistor R32 is electrically connected to pin 3 of digital converter U12;

[0070] Pin 16 of digital converter U12 is grounded, pins 7 and 8 of digital converter U12 are grounded, pin 5 of digital converter U12 is electrically connected to the first segment of current limiting resistor R35, the other end of current limiting resistor R35 is electrically connected to pin 3 of dual diode D3, the other end of current limiting resistor R35 and pin 3 of dual diode D3 are connected to power supply 5V1, and pin 2 of dual diode D3 is connected to power supply 5V2.

[0071] Pin 13 of digital converter U12, one end of current-limiting resistor R36, one end of filter capacitor C35, and one end of filter capacitor C37 are electrically connected. The other ends of filter capacitor C35 and C37 are grounded. The other end of current-limiting resistor R36 is connected to a 5V1 power supply. Pin 12 of digital converter U12, one end of filter capacitor C39, and one end of filter capacitor C40 are electrically connected. The other ends of filter capacitor C39 and C40 are grounded. Pin 9 of digital converter U12 is electrically connected to one end of current-limiting resistor R37. The other end of current-limiting resistor R37 is electrically connected to pin 3 of dual diode D4. Pin 1 of dual diode D4 is grounded. One end of dual diode D4 is connected to a 5V1 power supply. The other end of current-limiting resistor R37 is connected to pin 3 of dual diode D4, outputting 16V. The 16-bit digital input Vdat1, U9 / U10 are differential input instrumentation amplifiers with high input impedance, low offset, and low noise, adapted to the differential input of digital-to-analog converters, improving load capacity, and isolating the high-voltage divider circuit from the ADC; R24 and U8 (Zenigma diode) form a voltage regulator circuit, creating an internal reference source to provide a reference for pin 4 of U9 / U10; R27 / R28 and C31 / C32 are feedback resistors and capacitors, forming the AC feedback of the op-amp, filtering out DC bias, optimizing high-frequency response, and R27=R28 to ensure differential symmetry; R31 / R32 limit the current flowing into the ADS1203, protecting the ADC, and also form an RC filter to suppress high-frequency interference; U12 is a 16-bit digital converter with ±250mV full-scale input, perfectly adapted to the low-voltage differential signal after high-voltage division, and is one of the core processing chips of the voltage sensor; D3 and R35 are clock input protection, D3 R35 is a bidirectional TVS resistor that absorbs clock signal surges, and R36 limits the current to protect the MCLK input. C39 / C40 provides filtering for digital circuits, isolating digital noise from the analog power supply. R36 and C35 / C37, where R36 is a current-limiting resistor and C35 and C37 combine for high and low frequency filtering, provide a clean analog 5V power supply to the microcontroller. D4 is a bidirectional TVS resistor, and R37 limits the current to protect the MDAT output and prevent high voltage from entering the microcontroller.

[0072] Reference Figure 7The microcontroller internally includes a passive crystal oscillator Y1, oscillation capacitors C1 and C2, a load resistor R3, a pull-up resistor R4, a filter capacitor C7, pin headers J1 and J2, a resistor R1, the microcontroller U2, decoupling capacitors C12, C13, and C14. Pin 4 of the microcontroller U2, one end of the filter capacitor C7, and one end of the pull-up resistor R4 are electrically connected. The other end of the filter capacitor C7 is grounded, and the other end of the pull-up resistor R4 is connected to 3.3. A 3.3V power supply is connected to pin 31 of microcontroller U2, which is electrically connected to pin 2 of pin header J1. Pin 1 of pin header J1 is connected to a 3.3V power supply. Pin 3 of pin header J1 is electrically connected to one end of resistor R1, and the other end of resistor R1 is grounded. Pin 2 of microcontroller U2, one end of load resistor R3, one end of oscillation capacitor C1, and pin 3 of passive crystal oscillator Y1 are electrically connected. Pin 3 of microcontroller U2, the other end of load resistor R3, pin 1 of passive crystal oscillator Y1, and one end of oscillation capacitor C2 are electrically connected to start oscillation. The other end of capacitor C2, the other end of oscillation capacitor C1, and pin 2 of passive crystal oscillator Y1 are electrically connected. The other ends of oscillation capacitors C2 and C1, and pin 2 of passive crystal oscillator Y1 are grounded. Pin 4 of passive crystal oscillator Y1 is grounded. Pins 16 and 32 of microcontroller U2 are grounded respectively. Pin 20 of microcontroller U2 is electrically connected to pin 2 of pin header J2. Pin 21 of microcontroller U2 is electrically connected to pin 3 of pin header J2. Pin 1 of pin header J2 is connected to a 3.3V power supply. Pin 4 of J2 is grounded. Pins 1, 17, and 5 of microcontroller U2, one end of decoupling capacitor C12, one end of decoupling capacitor C13, and one end of decoupling capacitor C14 are electrically connected. The other ends of decoupling capacitors C12, C13, and C14 are grounded respectively. Passive crystal oscillator Y1 is used, along with starting capacitors C1 and C2 (typical value 20-33pF) and load resistor R3; BOOT0 The pins are configured via jumper cap J1: pins 1 and 2 are shorted to boot from system memory for serial firmware programming; pins 3 and 2 are shorted to boot from main Flash for normal program operation. For mass production, a 10kΩ pull-down resistor can be directly soldered to ground to fix the Flash boot mode, eliminating the need for the jumper cap. Pull-up resistor R4 and filter capacitor C7 form the power-on automatic reset module. J2 header pins can be used for program download, debugging, and serial communication. PA3 is the data signal input port. Three decoupling capacitors (typically 0.1μF) C12, C13, and C14 are used to filter power supply noise and ensure stable power supply, crucial for stable microcontroller operation. U3-OUT is the signal output port. U2 is the microcontroller, powered by 3.3V, and includes crystal oscillator, reset, debug, input, and output ports.

[0073] Reference Figure 8The signal power amplifier module internally includes a NAND gate driver circuit U1, filter capacitors C6 and C10, current-limiting resistors R2, C3, and R6, filter capacitor C15, DC blocking capacitor C11, resistor R5, and a high-frequency dual-group coil T1. Pin 1 of the NAND gate driver circuit U1 is electrically connected to one end of resistor R5, and the other end of resistor R5 is grounded. Pin 2 of the NAND gate driver circuit U1 is connected to Vdat1. Pin 3 of the NAND gate driver circuit U1 is electrically connected to one end of current-limiting resistor R6. The other end of current-limiting resistor R6, one end of filter capacitor C15, and pin 2 of the high-frequency dual-group coil T1 are electrically connected. Pin 4 of the NAND gate driver circuit U1 is grounded. Pin 1 of the high-frequency dual-group coil T1 is electrically connected to one end of DC blocking capacitor C11. The other end of DC blocking capacitor C11, one end of filter capacitor C3, and current-limiting resistor R2 are electrically connected to the high-frequency dual-group coil T1. One end of the circuit is electrically connected to the current-limiting resistor R2, and the other end of the NAND gate driver circuit U1 is electrically connected to pin 7. The other end of the filter capacitor C3 is grounded. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are electrically connected. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are connected to a 5V1 power supply. The other ends of the filter capacitor C6 and the other ends of the filter capacitor C10 are grounded respectively. Pin 5 of the NAND gate driver circuit U1 is connected to Vdat1, and pin 6 of the NAND gate driver circuit U1 is connected to 5V2. Pin 3 of the high-frequency dual-group coil T1 is grounded, and pin 4 of the high-frequency dual-group coil T1 outputs PA3. U1 is a set of two NAND gate circuits. When A and B are both 1, the output Y is 0; otherwise, it is 1. C6 and C10 are high-frequency and low-frequency mixed filter capacitors for the power supply. R2 / C3 R6 / C15 current limiting filter protects the U1 output stage and suppresses surge current; C11 DC blocking capacitor blocks DC and transmits only AC / pulse signals to prevent transformer saturation; R5 input pull-down stabilizes the logic level and prevents floating misjudgment; T1 is a high-frequency dual-coil circuit that electrically isolates the signal output by U1 and transmits it to subsequent circuits.

[0074] Reference Figure 9The high-frequency oscillation circuit internally includes a controller chip U5, a decoupling capacitor C29, a soft-start capacitor C26, a timing resistor R13, a decoupling capacitor C22, a timing capacitor C23, a current-limiting resistor R20, a resistor R22, an external high-frequency transformer T1-A, an external high-frequency transformer T1-B, and a power switch Q1. Pins 13 and 15 of the controller chip U5 are electrically connected to one end of the decoupling capacitor C29. Pins 13 and 15 of the controller chip U5 and one end of the decoupling capacitor C29 are connected to a 5V power supply, and the other end of the decoupling capacitor C29 is grounded. Pin 16 of the controller chip U5, one end of the timing resistor R13, and one end of the decoupling capacitor C22 are electrically connected, and the other end of the timing resistor R13 is electrically connected to pin 6 of the controller chip U5. Connect the decoupling capacitor C22 to ground, pin 10 of controller chip U5 to ground, pins 5 and 7 of controller chip U5 to one end of timing capacitor C23, and the other end of timing capacitor C23 to ground, pin 8 of controller chip U5 to one end of soft-start capacitor C26, and the other end of soft-start capacitor C26 to ground, pin 14 of controller chip U5 outputs to drive external high-frequency transformer T1-B, pin 11 of controller chip U5 to one end of current-limiting resistor R20, the other end of current-limiting resistor R20 to pin 1 of power switch Q1, pin 2 of power switch Q1 to resistor R22, the other end of resistor R22 to ground, pin 3 of power switch Q1 outputs to drive external high-frequency transformer T1-A, and C29 is 5V. Power supply decoupling must be placed close to the chip pins; this is crucial for stable chip operation. C26 is a soft-start capacitor, enabling slow startup and protecting downstream power devices. R13 is a timing resistor connected to REF to set the oscillation frequency. C22 is a 0.1μF decoupling capacitor on the REF pin, stabilizing the internal 5.1V reference voltage. C23 is a timing capacitor that determines the oscillation frequency; a high-precision, low-temperature-drift C0G capacitor must be selected. R20 limits the instantaneous current during turn-on, and R22 pulls down to ensure gate charge discharge during turn-off, preventing false turn-on. T1-A and T1-B are external high-frequency transformers that drive the coils. Q1 is an N-channel enhancement-mode MOSFET, used as a power switch to drive the downstream transformer T1-A.

[0075] Reference Figure 10The linear signal output module internally includes a single power supply U4, a current-limiting resistor R8, a pull-up resistor R14, a pull-up resistor R19, an optocoupler U6, a pull-up resistor R16, a decoupling capacitor C28, a current-limiting resistor R21, a filter capacitor C30, a feedback resistor R26, a feedback resistor R23, a load resistor R29, operational amplifiers U7A and U7B, an op-amp input resistor R25, and an op-amp feedback resistor R30. Pin 6 of the single power supply U4, one end of the pull-up resistor R14, and one end of the current-limiting resistor R8 are electrically connected. The other end of the pull-up resistor R14 is connected to a 5V power supply. The other end of resistor R8 is connected to the U3-OUT signal. Pin 3 of single-supply U4 is grounded. Pin 5 of single-supply U4 is connected to a 5V power supply. Pin 2 of single-supply U4 is grounded. Pin 1 of single-supply U4, one end of pull-up resistor R19, and one end of optocoupler U6 are electrically connected. The other end of pull-up resistor R19 is connected to a 5V power supply. The other end of optocoupler U6 is grounded. Pin 4 of single-supply U4 is electrically connected to one end of pull-up resistor R16. The other end of pull-up resistor R16, one end of decoupling capacitor C28, and one end of current-limiting resistor R21 are electrically connected. The other end of decoupling capacitor C28 is electrically connected to... The other end of R21, one end of the filter capacitor C30, and pin 3 of operational amplifier U7A are electrically connected. The other end of the filter capacitor C30 is grounded. Pins 1 and 2 of operational amplifier U7A are electrically connected to one end of the op-amp input resistor R25. The other end of the op-amp input resistor R25, one end of the feedback resistor R26, and pin 6 of operational amplifier U7B are electrically connected. The other end of the feedback resistor R26, one end of the feedback resistor R23, and one end of the load resistor R29 are electrically connected. The other end of the feedback resistor R23 is connected to a +15V power supply, and the other end of the load resistor R29 is connected to a -1V power supply. A 5V power supply is used. Pin 5 of operational amplifier U7B is electrically connected to one end of the op-amp feedback resistor R30, and the other end of the op-amp feedback resistor R30 is electrically connected to pin 7 of operational amplifier U7B. The other end of the op-amp feedback resistor R30 is connected to the output Vout of pin 7 of operational amplifier U7B. U4 is a single-supply, bidirectional, SPDT (single-pole double-throw) analog switch, which performs threshold judgment, channel switching, and level clamping protection on the input U3-OUT signal. It is commonly used in signal isolation, zero-crossing detection, and multi-channel signal gating scenarios. R8 is an input current-limiting resistor, which limits the input current of U3-OUT and protects U4. The Vin pin is protected against overcurrent damage; R14 is a pull-up resistor that pulls the Vin pin potential up to 5V, which, together with the input signal, enables high and low level judgment and ensures reliable switching; R19 and U6 form a voltage regulator circuit, providing a reliable and stable internal reference voltage; R16, C28, R21, and C30 form a second-order RC low-pass filter circuit, which filters out high-frequency noise and spike interference in the input signal, smooths the waveform, and retains useful low-frequency / power frequency signals. In this circuit, the pulse signal is filtered and rectified into a DC signal.U7 is a dual operational amplifier that amplifies the input signal to the output; R26, R23, and R29 form a reference voltage for the op-amp input; R25 is the op-amp input resistor; R30 is the op-amp feedback resistor.

[0076] Working Principle: The high-voltage voltage divider module includes a series voltage divider resistor R9; one end of resistor R9 is connected to the input high voltage 2000V+; the other end of resistor R9 is connected to resistor R10, capacitor C24, and resistor R17; resistor R10 is connected to resistor R11; resistor R11 is connected to resistor R12, capacitor C25, and resistor R18; resistor R12 is connected to the high-voltage input 2000V-; one end of capacitor C27 is connected to R17 and output Vin+; the other end of capacitor C27 is connected to R18 and output Vin-. The 2000V+ and 2000V- high-voltage inputs are divided by four series high-impedance resistors R9, R10, R11, and R12, and differential low-voltage signals are extracted at the upper and lower nodes of R10 and R11; C24 and C25 perform common-mode filtering at the upper and lower nodes respectively to suppress common-mode interference and surge spikes on the high-voltage side; R17 and R18 provide current-limiting protection for the differential signal, and simultaneously work with C27... An RC low-pass filter is formed to filter out differential-mode high-frequency noise, and finally outputs stable and clean mV-level differential signals Vin+ and Vin-, which are sent to the subsequent amplification and digital-to-analog conversion module to realize accurate sampling and digital conversion of high-voltage signals.

[0077] The amplification digital-to-analog converter module includes operational amplifier U9; the non-inverting input terminal (pin 3) of operational amplifier U9 is connected to the input signal Vin+, feedback capacitor C31, and feedback resistor R22; the inverting input terminal (pin 4) of operational amplifier U9 is connected to the reference voltage REF, resistor R24, and Zener diode U8; the other end of resistor R24 ​​is connected to the 5V power supply; the other end of Zener diode U8 is connected to ground GND; the output terminal (pin 1) of operational amplifier U10 is connected to the feedback capacitor C31, feedback resistor R27, and output resistor R31; the non-inverting input terminal (pin 3) of operational amplifier U10 is connected to the input signal Vin-, feedback capacitor C32, and feedback resistor R28; the inverting input terminal (pin 4) of operational amplifier U10 is connected to the reference voltage REF; the output terminal (pin 1) of operational amplifier U10 is connected to the feedback capacitor C32, feedback resistor R28, and output resistor R32;

[0078] The amplification digital-to-analog converter module includes a digital-to-analog converter U12; pin 13 (AVDD) of the digital-to-analog converter U12 is connected to resistor R36, the positive terminal of capacitor C35, and capacitor C37; the other end of resistor R36 is connected to 5V (5V1); pin 12 (BVDD) of the digital-to-analog converter is connected to the 5V1 power supply, capacitors C39 and C40; pins 7 (AGND), 8 (BGND), and 16 (M0) of the digital-to-analog converter are connected to ground GND; pin 5 (M1) of the digital-to-analog converter U7 is connected to resistor R35; resistor R... Connect pin 3 of dual diode D3 to power supply 5V1; connect pin 1 of dual diode to ground GND; connect pin 2 of dual diode to power supply 5V2; connect pin 2 (Vin+) of digital-to-analog converter U12 to R31; connect pin 3 (Vin-) of digital-to-analog converter U12 to R32; connect pin 9 (MDAT) of digital-to-analog converter U12 to R37; connect resistor R37 to pin 3 of dual diode D4 and Vdat1; connect pin 1 of dual diode D4 to ground GND; connect pin 2 of dual diode D4 to power supply 5V1.

[0079] The Vin+ and Vin- differential weak signals output from the high-voltage divider module are input to operational amplifiers U9 and U10, respectively. After active filtering and buffer amplification, they output stable analog differential signals. The amplified signals are then current-limited by R31 and R32 and input to the differential input of the digital-to-analog converter U12. Under a stable 5V1 power supply and reference voltage, U12 converts the analog signal into a 16-bit digital bitstream Vdat1. The digital signal is then current-limited by R37 and clamped by D4 before being output to the subsequent isolation driver module. This achieves high-precision and high-reliability conversion from analog to digital signals, providing accurate digital input for subsequent microcontroller processing.

[0080] The multi-channel isolated power supply module includes a ±24V to ±15V isolated DC-DC unit, a ±24V to 5V and then to 3.3V isolated DC-DC unit, and a 5V to 5V unit with oscillation isolation.

[0081] In the ±24V to ±15V isolated DC-DC unit, the isolated power supply PS2 is used. Pin 1 (+Vin) of PS2 is connected to diode D1, the positive terminal of filter capacitor C5, and filter capacitor C9. The other end of diode D1 is connected to the +24V power supply. Pin 2 (-Vin) of PS2 is connected to the -24V power supply, the negative terminal of filter capacitor C5, and filter capacitor C9. Pin 6 (+Vout) of PS2 is connected to the +15V output power supply, filter capacitor C18, and filter capacitor C21. The other end of filter capacitor C18 is connected to ground GND1. The other end of filter capacitor C21 is connected to ground GND1. Pin 4 (-Vout) of PS2 is connected to the -15V output power supply, filter capacitor C17, and filter capacitor C20. The other end of filter capacitor C17 is connected to ground GND1. The other end of filter capacitor C20 is connected to ground GND1. Pin 5 (0V) of PS2 is connected to ground GND1.

[0082] The ±24V to 5V and then to 3.3V isolated DC-DC unit uses the isolated power supply PS1. Pin 2 (+Vin) of PS1 is connected to diode D2, the positive terminal of filter capacitor C4, and filter capacitor C8. The other end of diode D2 is connected to the +24V power supply. Pin 1 (-Vin) of PS1 is connected to the -24V power supply, the negative terminal of filter capacitor C4, and filter capacitor C8. Pin 6 (+Vout) of PS1 is connected to the output 5V power supply, filter capacitors C16 and C19, and pin 3 (VI) of the low-dropout linear regulator U3. Pin 7 (-Vout) of PS1 is connected to ground GND1. Pin 1 (GND) of the low-dropout linear regulator U3 is connected to ground GND1. Pin 2 (VO) of the low-dropout linear regulator U3 is connected to the output voltage 3.3V.

[0083] In the 5V power conversion circuit, the high-frequency isolation coil T2 in the oscillating isolation to 5V unit is connected to the high-frequency signal T1-A terminal; pin 3 of the high-frequency isolation coil T2 is connected to the high-frequency signal T1-B terminal; pin 1 of the high-frequency isolation coil T2 is connected to the filter capacitor C43 and pin 3 of the dual diode D6; pin 2 of the high-frequency isolation coil T2 is connected to the filter capacitor C42 and the isolation capacitor C41; the other end of the filter capacitor C43 is connected to ground GND; the other end of the filter capacitor C42 is connected to ground GND; pin 2 of the dual diode D6 is connected to the filter capacitors C38 and C36, pins 1 and 3 of the high-precision power regulator chip U11, and the dual diode D5. Pin 2 of the high-precision power supply regulator chip U11 is connected to the following terminals: the other end of isolation capacitor C41 is connected to pin 3 of dual diode D5; pin 1 of dual diode D5 is connected to ground GND; the other end of filter capacitor C38 is connected to ground GND; the other end of filter capacitor C36 is connected to ground GND; pin 5 of high-precision power supply regulator chip U11 is connected to resistor R34; pin 4 of high-precision power supply regulator chip U11 is not connected; pin 4 of high-precision power supply chip U11 is connected to ground GND; resistor R34 is connected to power supply 5V1, filter capacitor C34, and resistor R33; the other end of filter capacitor 4 is connected to ground GND; resistor R33 is connected to power supply 5V2 and filter capacitor C33; the other end of filter capacitor C33 is connected to ground GND.

[0084] The power conversion input is ±24V (48V). One path passes through polarized diode D1, filter capacitors C5 and C9, then through PS2 power conversion, and after passing through filter capacitors C18, C21, C17, and C20, outputs a stable +15V and -15V. The other path passes through polarized diode D2, filter capacitors C4 and C8, then through PS1 power conversion, and after passing through filter capacitors C16 and C19, outputs a stable +5V. After passing through the precision voltage regulator circuit U3, the voltage is converted to 3.3V. The third power supply transmits high-frequency voltage signals through T2 for electrical isolation. After filtering by C42 and C43 and DC isolation by C41, the signals are rectified into DC signals by dual diodes D5 and D6. After voltage filtering, the signals are input to the high-precision voltage regulator chip U11. Through resistor R34 and filter capacitor C34, a high-precision and stable 5V power supply (5V1) is output, which serves as the operating power supply for the core components. Then, through a small-value resistor R33 and filter capacitor C33, a 5V power supply (5V2) is output, which serves as the high-level input voltage in the circuit.

[0085] The microcontroller processing module includes an STM32 series microcontroller U2. Pins 1 (VDD), 17 (VDD), and 5 (VDDA) of microcontroller U2 are connected to a 3.3V power supply, filter capacitors C12, C13, and C14. Pins 16 (VSS) and 32 (VSS) of microcontroller U2 are connected to ground GND1. Pin 4 (NRST) of microcontroller U2 is connected to resistor R4 and capacitor C7; the other end of resistor R4 is connected to the 3.3V power supply; the other end of capacitor C7 is connected to ground (GND1). Pin 31 (BOOT0) of microcontroller U2 is connected to pin 2 of header J1; pin 1 of header J1 is connected to the 3.3V power supply; pin 3 of header J1 is connected to resistor R1, the other end of which is connected to ground GND1. Pin 2 (PF0) of microcontroller U2 is connected to oscillation resistor R3 and oscillation... The oscillating capacitor C1 and pin 3 of crystal oscillator Y1 are connected; pin 3 (PF1) of the microcontroller is connected to the other end of the oscillation resistor R3, the oscillation capacitor C2, and pin 1 of crystal oscillator Y1; pins 2 and 4 of crystal oscillator Y1 are connected to ground GND1; the other end of oscillation capacitor C1 is connected to ground GND1; the other end of oscillation capacitor C2 is connected to ground GND1; pin 9 (PA3) of microcontroller U2 is connected to the output signal PA3 of the isolation drive module, serving as the input signal of the microcontroller; pin 20 (PA10) of microcontroller U2 is connected to pin 2 of pin header J2; pin 21 (PA11) of the microcontroller is connected to pin 3 of pin header J2; pin 1 of pin header J2 is connected to the 3.3V power supply; pin 4 of pin header J2 is connected to ground GND1; pin 24 (PA15) of the microcontroller is connected to the output signal U3-OUT.

[0086] C12 / C13 / C14, connected externally to microcontroller U2, are power supply decoupling capacitors, located near the VDD / VDDA pins, to filter power supply ripple and suppress interference; resistor R4 and capacitor C7 form a power-on reset circuit; J1 is an optional debug / startup mode switching interface, high level for download mode, low level for normal operation mode; J2 is the program download port and parameter debugging interface, connected to the PA9, PA10, PA11, and PA12 pins of microcontroller U2 for program download and debugging; oscillation resistor R3, oscillation capacitors C1 and C2, and crystal oscillator Y1 form the external oscillation input of the microcontroller, connected to the PF0 and PF1 pins of U2, providing the system clock for the microcontroller; pin 9 of the microcontroller is the signal input port PA3, and pin 24 is the microcontroller output port U3-OUT.

[0087] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-precision voltage sensor, comprising a sensor power supply, a first power conversion circuit, a first electrical isolation module, a high-frequency oscillation circuit, a second power conversion circuit, a third power conversion circuit, a high-voltage precision-to-low-voltage conversion module, an amplification digital-to-analog conversion module, a signal power amplification module, a second electrical isolation module, a microcontroller, and a linear signal output module, characterized in that: The sensor power output terminal is electrically connected to a high-frequency oscillation circuit, a microcontroller, and a linear signal output module, respectively. A second power conversion circuit is provided between the sensor power supply and the microcontroller. A third power conversion circuit is provided between the sensor power supply and the linear signal output module. The microcontroller and the linear signal output module are electrically connected. The output terminal of the high-frequency oscillation circuit is electrically connected to a high-voltage precision-to-low-voltage module, an amplification digital-to-analog conversion module, and a signal power amplification module, respectively. A first electrical isolation module and a first power conversion circuit are provided between the high-frequency oscillation circuit and the low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module. The high-voltage precision-to-low-voltage module, the amplification digital-to-analog conversion module, and the signal power amplification module are electrically connected. The signal power amplification module is electrically connected to the microcontroller. A second electrical isolation module is provided between the signal power amplification module and the microcontroller. The power supply for the sensor is the power supply for the voltage sensor, which is used to provide an external power source for the sensor to operate. Generally, the power supply is a dual power supply of ±24V, ±15V, and ±12V, but it can also be a single power supply. The first power conversion circuit provides a high-precision 5V power supply to the high-voltage precision to low-voltage conversion module, the amplification digital-to-analog conversion module, and the signal power amplification module; The second power conversion circuit converts the power supply voltage to 3.3V via a DC-DC module to power the microcontroller. The third power conversion circuit converts the power supply voltage to ±15V via a DC-DC module for use by the subsequent linear signal output module circuit. The first electrical isolation module transmits the high-frequency signal to the secondary coil through a high-frequency transformer via a high-frequency oscillation circuit. The high-frequency coil transmits the oscillation waveform to the secondary coil, which, after rectification, filtering, and high-precision voltage regulation, forms a high-precision regulated voltage. At the same time, the isolation module achieves high-voltage isolation. The second electrical isolation module transmits a 1-bit digital bitstream signal to the secondary coil through a high-frequency transformer. The high-frequency coil is used to accurately transmit signal data and provide high-voltage isolation. The high-voltage precision to low-voltage conversion module divides the high voltage using a high-resistance, high-power precision resistor and samples the voltage using a low-impedance precision resistor, converting the high voltage into a relatively low voltage. The amplified digital-to-analog converter module is used to ensure that the input signal of the digital-to-analog converter does not damage the digital-to-analog converter; A digital-to-analog converter (DAC) converts analog signals into a 1-bit serial bit stream; a 16-bit resolution DAC may be selected. The signal power amplification module is a signal amplification circuit. The microcontroller converts the input signal from the digital-to-analog converter into a pulse-width modulated waveform through data processing and logic judgment. The linear signal output module is used to rectify and filter the pulse output waveform into a linear output voltage that varies with the input signal. Alternatively, it can form a current output signal that varies with the input signal through a BTL (bridged load) complementary symmetrical power amplifier circuit driven by an operational amplifier. The high-frequency oscillation circuit uses a classic voltage-type PWM controller to generate a set high-frequency oscillation circuit, which drives a high-frequency transformer and generates a stable operating voltage through a second electrical isolation module and a low-dropout (LDO) linear regulator.

2. The high-precision voltage sensor according to claim 1, characterized in that: The first power conversion circuit includes a diode D1, an electrolytic capacitor C5, a ceramic capacitor C9, a dual-channel isolated DC-DC power module PS2, a filter capacitor C18, a filter capacitor C21, a filter capacitor C17, and a filter capacitor C20.

3. A high-precision voltage sensor according to claim 2, characterized in that: One end of diode D1 is connected to a +24V power supply. The other end of diode D1, one end of electrolytic capacitor C5, one end of ceramic capacitor C9, and pin 1 of the dual-channel isolated DC-DC power module PS2 are electrically connected. The other end of electrolytic capacitor C5, the other end of ceramic capacitor C9, and pin 2 of the dual-channel isolated DC-DC power module PS2 are electrically connected to a -24V power supply. Pin 4 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C17, and one end of filter capacitor C20 are electrically connected. The other end of capacitor 7 and the other end of filter capacitor C20 are respectively grounded. Pin 5 of the dual-channel isolated DC-DC power module PS2 is grounded. Pin 4 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C17 and one end of filter capacitor C20 output -15V power. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18 and one end of filter capacitor C21 are electrically connected. The other end of filter capacitor C18 and the other end of filter capacitor C21 are respectively grounded. Pin 6 of the dual-channel isolated DC-DC power module PS2, one end of filter capacitor C18 and one end of filter capacitor C21 output +15V power.

4. A high-precision voltage sensor according to claim 3, characterized in that: The second power conversion circuit includes a diode D2, an electrolytic capacitor C4, a ceramic capacitor C8, a single-channel isolated DC-DC power module PS1, a filter capacitor C16, a filter capacitor C19, and a voltage regulator U3.

5. A high-precision voltage sensor according to claim 4, characterized in that: One end of diode D2 is connected to a +24V power supply. The other end of diode D2, one end of electrolytic capacitor C4, one end of ceramic capacitor C8, and pin 2 of single-channel isolated DC-DC power supply module PS1 are electrically connected. The other end of electrolytic capacitor C4, the other end of ceramic capacitor C8, and pin 1 of single-channel isolated DC-DC power supply module PS1 are electrically connected to a -24V power supply. Pin 6 of single-channel isolated DC-DC power supply module PS1, one end of filter capacitor C16, one end of filter capacitor C19, and pin 3 of voltage regulator U3 are electrically connected. Pin 7 of single-channel isolated DC-DC power supply module PS1 is grounded. Pin 6 of single-channel isolated DC-DC power supply module PS1 outputs 5V power. The other ends of filter capacitor C16 and filter capacitor C19 are grounded respectively. Pin 1 of voltage regulator U3 is grounded. Pin 2 of voltage regulator U3 outputs 3.3V power.

6. A high-precision voltage sensor according to claim 5, characterized in that: The third power conversion circuit includes a high-frequency isolation signal transformer T2, ceramic capacitors C42 and C43, isolation capacitor C41, Schottky diodes D5 and D6, filter capacitors C36 and C38, a high-precision power regulator chip U11, resistors R33 and R34, and filter capacitors C33 and C34.

7. A high-precision voltage sensor according to claim 6, characterized in that: Pin 4 of the high-frequency isolation signal transformer T2 is connected to high-frequency signal T1-A, and pin 3 of the high-frequency isolation signal transformer T2 is connected to high-frequency signal T1-B. Pin 1 of the high-frequency isolation signal transformer T2, one end of ceramic capacitor C43, and pin 3 of Schottky diode D6 are electrically connected. Pin 1 of Schottky diode D6 is grounded. Pin 2 of the high-frequency isolation signal transformer T2, one end of ceramic capacitor C42, and one end of isolation capacitor C41 are electrically connected. The other end of ceramic capacitor C42 is grounded. The other end of isolation capacitor C41 is electrically connected to pin 3 of Schottky diode D5. Pin 1 of Schottky diode D5 is grounded. Pin 2 of Schottky diode D5, pin 2 of Schottky diode D6, and filter capacitor C3 are connected. One end of capacitor C38, one end of filter capacitor C36, pin 1 and pin 3 of high-precision power regulator chip U11 are electrically connected. The other ends of filter capacitor C38 and filter capacitor C36 are grounded respectively. Pin 2 of high-precision power regulator chip U11 is grounded. Pin 5 of high-precision power regulator chip U11 is electrically connected to one end of resistor R34. The other end of resistor R34, one end of filter capacitor C34 and one end of resistor R33 are electrically connected. The other end of filter capacitor C34 is grounded. The other end of resistor R33 is connected to one end of filter capacitor C33. The other end of filter capacitor C33 is grounded. The other end of resistor R33 is connected to the output 5V2 power supply of filter capacitor C33.

8. A high-precision voltage sensor according to claim 7, characterized in that: The high-voltage precision conversion module for low-voltage conversion includes a high-voltage resistor R9, a high-voltage resistor R12, a voltage divider resistor R10, a voltage divider resistor R11, a filter capacitor C24, a filter capacitor C25, a current-limiting resistor R17, a current-limiting resistor R18, and a differential capacitor C27. One end of the high-voltage resistor R9 is connected to a 2000V+ voltage, and one end of the high-voltage resistor R12 is connected to a 2000V- voltage. The other ends of the high-voltage resistor R9, one end of the voltage divider resistor R10, one end of the filter capacitor C24, and one end of the current-limiting resistor R17 are electrically connected. The other end of the filter capacitor C24 is grounded. The other end of resistor R12, one end of voltage divider resistor R11, one end of filter capacitor C25, and one end of current limiting resistor R18 are electrically connected. The other end of filter capacitor C25 is grounded. The other end of voltage divider resistor R11 and the other end of voltage divider resistor R10 are electrically connected. The other end of current limiting resistor R17 and one end of differential capacitor C27 are electrically connected. The other end of current limiting resistor R17 and one end of differential capacitor C27 output Vin+. The other end of current limiting resistor R18 and the other end of differential capacitor C27 are electrically connected. The other end of current limiting resistor R18 and the other end of differential capacitor C27 output Vin-.

9. A high-precision voltage sensor according to claim 8, characterized in that: The amplified digital-to-analog converter module internally includes operational amplifier U9, operational amplifier U10, Zener diode U8, resistor R24, feedback resistor R27, feedback resistor R28, feedback capacitor C31, feedback capacitor C32, output resistor R31, output resistor R32, dual diode D3, digital converter U12, current-limiting resistor R35, filter capacitor C39, filter capacitor C40, filter capacitor C35, filter capacitor C37, current-limiting resistor R36, dual diode D4, and current-limiting resistor R37. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are electrically connected. Pin 3 of operational amplifier U9, one end of feedback resistor R27, and one end of feedback capacitor C31 are connected to Vin+. Pin 4 of operational amplifier U9, one end of resistor R24, and one end of Zener diode U8 are electrically connected. The other end of Zener diode U8... The circuit is grounded. The other end of the resistor R24 ​​is connected to a 5V power supply. The other end of the feedback capacitor C31, the other end of the feedback resistor R27, pin 1 of the operational amplifier U9, and one end of the output resistor R31 are electrically connected. One end of the operational amplifier U9 is grounded. The other end of the output resistor R31 is electrically connected to pin 2 of the digital converter U12. Pin 3 of the operational amplifier U10, one end of the feedback capacitor C32, and one end of the feedback resistor R28 are electrically connected. Pin 3 of the operational amplifier U10, one end of the feedback capacitor C32, and one end of the feedback resistor R28 are connected to Vin-. One end of the operational amplifier U10 is grounded. The other end of the feedback capacitor C32, the other end of the feedback resistor R28, pin 1 of the operational amplifier U10, and one end of the output resistor R32 are electrically connected. The other end of the output resistor R32 is electrically connected to pin 3 of the digital converter U12. Pin 16 of the digital converter U12 is grounded, pins 7 and 8 of the digital converter U12 are grounded, pin 5 of the digital converter U12 is electrically connected to the first segment of the current limiting resistor R35, the other end of the current limiting resistor R35 is electrically connected to pin 3 of the dual diode D3, the other end of the current limiting resistor R35 and pin 3 of the dual diode D3 are connected to power supply 5V1, and pin 2 of the dual diode D3 is connected to power supply 5V2. The digital converter U12 has its pin 13, one end of the current-limiting resistor R36, one end of the filter capacitor C35, and one end of the filter capacitor C37 electrically connected. The other ends of the filter capacitors C35 and C37 are grounded. The other end of the current-limiting resistor R36 is connected to a 5V1 power supply. The digital converter U12 has its pin 12, one end of the filter capacitor C39, and one end of the filter capacitor C40 electrically connected. The other ends of the filter capacitors C39 and C40 are grounded. The digital converter U12 has its pin 9, one end of the current-limiting resistor R37 electrically connected to pin 3 of the dual diode D4. Pin 1 of the dual diode D4 is grounded. One end of the dual diode D4 is connected to a 5V1 power supply. The other end of the current-limiting resistor R37 and pin 3 of the dual diode D4 output a 16-bit digital bitstream Vdat1.

10. A high-precision voltage sensor according to claim 9, characterized in that: The microcontroller internally includes a passive crystal oscillator Y1, oscillation capacitors C1 and C2, a load resistor R3, a pull-up resistor R4, a filter capacitor C7, pin headers J1 and J2, a resistor R1, a microcontroller U2, decoupling capacitors C12, C13, and C14. Pin 4 of the microcontroller U2, one end of the filter capacitor C7, and one end of the pull-up resistor R4 are electrically connected. The other end of the filter capacitor C7 is grounded. The pull-up resistor R4... The other end is connected to a 3.3V power supply. Pin 31 of the microcontroller U2 is electrically connected to pin 2 of the header J1. Pin 1 of the header J1 is connected to a 3.3V power supply. Pin 3 of the header J1 is electrically connected to one end of resistor R1, and the other end of resistor R1 is grounded. Pin 2 of the microcontroller U2, one end of the load resistor R3, one end of the oscillation capacitor C1, and pin 3 of the passive crystal oscillator Y1 are electrically connected. Pin 3 of the microcontroller U2, the other end of the load resistor R3, and the passive crystal oscillator Y1 are also electrically connected. One end of the starting capacitor C2 is electrically connected to pin 1 of the crystal oscillator Y1. The other ends of the starting capacitor C2 and C1 are electrically connected to pin 2 of the passive crystal oscillator Y1. The other ends of the starting capacitor C2 and C1 are grounded to pin 2 of the passive crystal oscillator Y1. Pin 4 of the passive crystal oscillator Y1 is grounded. Pins 16 and 32 of the microcontroller U2 are grounded respectively. Pin 20 of the microcontroller U2 is electrically connected to pin 2 of the header J2. Pin 21 of U2 is electrically connected to pin 3 of pin header J2. Pin 1 of pin header J2 is connected to a 3.3V power supply. Pin 4 of pin header J2 is grounded. Pin 1, pin 17, pin 5 of microcontroller U2, one end of decoupling capacitor C12, one end of decoupling capacitor C13, and one end of decoupling capacitor C14 are electrically connected. The other ends of decoupling capacitors C12, C13, and C14 are grounded respectively.

11. A high-precision voltage sensor according to claim 10, characterized in that: The signal power amplification module internally includes a NAND gate driver circuit U1, filter capacitors C6 and C10, current-limiting resistors R2, C3, R6, C15, DC blocking capacitor C11, resistor R5, and a high-frequency dual-group coil T1. Pin 1 of the NAND gate driver circuit U1 is electrically connected to one end of resistor R5, and the other end of resistor R5 is grounded. Pin 2 of the NAND gate driver circuit U1 is connected to Vdat1. Pin 3 of the NAND gate driver circuit U1 is electrically connected to one end of the current-limiting resistor R6. The other end of the current-limiting resistor R6, one end of filter capacitor C15, and pin 2 of the high-frequency dual-group coil T1 are electrically connected. Pin 4 of the NAND gate driver circuit U1 is grounded. Pin 1 of the high-frequency dual-group coil T1 is electrically connected to one end of the DC blocking capacitor C11. The other end of the DC capacitor C11, one end of the filter capacitor C3, and one end of the current-limiting resistor R2 are electrically connected. The other end of the current-limiting resistor R2 is electrically connected to pin 7 of the NAND gate driver circuit U1. The other end of the filter capacitor C3 is grounded. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are electrically connected. Pin 8 of the NAND gate driver circuit U1, one end of the filter capacitor C6, and one end of the filter capacitor C10 are connected to a 5V1 power supply. The other ends of the filter capacitor C6 and the other ends of the filter capacitor C10 are grounded respectively. Pin 5 of the NAND gate driver circuit U1 is connected to Vdat1. Pin 6 of the NAND gate driver circuit U1 is connected to 5V2. Pin 3 of the high-frequency dual-group coil T1 is grounded. Pin 4 of the high-frequency dual-group coil T1 outputs PA3.

12. A high-precision voltage sensor according to claim 11, characterized in that: The high-frequency oscillation circuit internally includes a controller chip U5, a decoupling capacitor C29, a soft-start capacitor C26, a timing resistor R13, a decoupling capacitor C22, a timing capacitor C23, a current-limiting resistor R20, a resistor R22, an external high-frequency transformer T1-A, an external high-frequency transformer T1-B, and a power switch Q1. Pins 13 and 15 of the controller chip U5 are electrically connected to one end of the decoupling capacitor C29. Pins 13 and 15 of the controller chip U5 and one end of the decoupling capacitor C29 are connected to a 5V power supply, and the other end of the decoupling capacitor C29 is grounded. Pin 16 of the controller chip U5, one end of the timing resistor R13, and one end of the decoupling capacitor C22 are electrically connected. The other end of the timing resistor R13 is electrically connected to pin 6 of the controller chip U5. The other end of decoupling capacitor C22 is grounded. Pin 10 of controller chip U5 is grounded. Pins 5 and 7 of controller chip U5 are electrically connected to one end of timing capacitor C23, and the other end of timing capacitor C23 is grounded. Pin 8 of controller chip U5 is electrically connected to one end of soft-start capacitor C26, and the other end of soft-start capacitor C26 is grounded. Pin 14 of controller chip U5 outputs a drive for external high-frequency transformer T1-B. Pin 11 of controller chip U5 is electrically connected to one end of current-limiting resistor R20. The other end of current-limiting resistor R20 is electrically connected to pin 1 of power switch Q1. Pin 2 of power switch Q1 is electrically connected to resistor R22, and the other end of resistor R22 is grounded. Pin 3 of power switch Q1 outputs a drive for external high-frequency transformer T1-A.

13. A high-precision voltage sensor according to claim 12, characterized in that: The linear signal output module internally includes a single power supply U4, a current-limiting resistor R8, a pull-up resistor R14, a pull-up resistor R19, an optocoupler U6, a pull-up resistor R16, a decoupling capacitor C28, a current-limiting resistor R21, a filter capacitor C30, a feedback resistor R26, a feedback resistor R23, a load resistor R29, operational amplifiers U7A and U7B, an op-amp input resistor R25, and an op-amp feedback resistor R30. Pin 6 of the single power supply U4, one end of the pull-up resistor R14, and one end of the current-limiting resistor R8 are electrically connected. The other end of the pull-up resistor R14 is connected to a 5V power supply, the other end of the current-limiting resistor R8 is connected to the U3-OUT signal, pin 3 of the single power supply U4 is grounded, pin 5 of the single power supply U4 is connected to a 5V power supply, pin 2 of the single power supply U4 is grounded, pin 1 of the single power supply U4, one end of the pull-up resistor R19, and one end of the optocoupler U6 are electrically connected, the other end of the pull-up resistor R19 is connected to a 5V power supply, the other end of the optocoupler U6 is grounded, and pin 4 of the single power supply U4 is electrically connected to one end of the pull-up resistor R16. The other end of resistor R16, one end of decoupling capacitor C28, and one end of current-limiting resistor R21 are electrically connected. The other end of decoupling capacitor C28 is electrically connected. The other end of current-limiting resistor R21, one end of filter capacitor C30, and pin 3 of operational amplifier U7A are electrically connected. The other end of filter capacitor C30 is grounded. Pins 1 and 2 of operational amplifier U7A and one end of op-amp input resistor R25 are electrically connected. The other end of op-amp input resistor R25, one end of feedback resistor R26, and operational amplifier U7B are electrically connected. The 6th pin of the operational amplifier U7B is electrically connected. The other end of the feedback resistor R26, one end of the feedback resistor R23, and one end of the load resistor R29 are electrically connected. The other end of the feedback resistor R23 is connected to a +15V power supply, and the other end of the load resistor R29 is connected to a -15V power supply. The 5th pin of the operational amplifier U7B is electrically connected to one end of the operational amplifier feedback resistor R30. The other end of the operational amplifier feedback resistor R30 is electrically connected to the 7th pin of the operational amplifier U7B, which outputs Vout.

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