A high voltage power equipment monitoring circuit

Abstract

The utility model discloses a kind of high-voltage power equipment monitoring circuit, including main control MCU circuit, isolation voltage reduction circuit, attenuation circuit, instrument amplification circuit, gain adjustment circuit;Main control MCU circuit is connected isolation voltage reduction circuit, attenuation circuit, instrument amplification circuit respectively, the input end of isolation voltage reduction circuit connects input voltage, the output end of isolation voltage reduction circuit connects the input end of attenuation circuit, the output end of attenuation circuit connects the input end of instrument amplification circuit, gain adjustment circuit connects instrument amplification circuit;Gain adjustment circuit includes analog electronic switch, analog electronic switch is connected main control MCU circuit and instrument amplification circuit respectively.The utility model provides the monitoring circuit scheme of simultaneously setting attenuation circuit and instrument amplification circuit, and sets isolation voltage reduction circuit to protect, simultaneously, gain adjustment circuit can be adjusted gain amplification multiple in real time, higher high-voltage signal monitoring precision is realized, and monitoring safety and stability are improved.

Description

Technical Field

[0001] This utility model relates to the field of power equipment monitoring technology, and in particular to a high-voltage power equipment monitoring circuit. Background Technology

[0002] In the field of high-voltage power equipment monitoring, traditional technical solutions typically employ simple voltage divider resistor networks or fixed-gain amplifier circuits to acquire voltage signals. However, both of these solutions have drawbacks: Voltage divider resistor attenuation networks have a fixed attenuation factor that cannot adapt to different voltage ranges, requiring frequent replacement of the voltage divider resistors, making operation cumbersome; fixed-gain amplifier circuits cannot match the signal amplitude after different attenuation levels, leading to range overflow or reduced resolution during ADC acquisition. Furthermore, both solutions lack integrated electrical isolation mechanisms; some solutions only use simple hardware filtering to handle interference signals, making them suitable only for low-voltage signal acquisition but unsuitable for high-voltage signal acquisition, resulting in insufficient monitoring accuracy and potential safety hazards. Utility Model Content

[0003] The purpose of this utility model is to overcome the shortcomings of the prior art. This utility model provides a high-voltage power equipment monitoring circuit, which provides a monitoring circuit scheme that simultaneously sets up an attenuation circuit and an instrument amplification circuit, and sets up an isolation step-down circuit for protection. At the same time, the gain amplification factor can be adjusted in real time through a gain adjustment circuit to achieve higher high-voltage signal monitoring accuracy and improve monitoring safety and stability.

[0004] This utility model provides a high-voltage power equipment monitoring circuit, which includes a main control MCU circuit, an isolation step-down circuit, an attenuation circuit, an instrumentation amplifier circuit, and a gain adjustment circuit.

[0005] The main control MCU circuit is connected to the isolation step-down circuit, the attenuation circuit, and the instrumentation amplifier circuit respectively. The input terminal of the isolation step-down circuit is connected to the power supply voltage, the output terminal of the isolation step-down circuit is connected to the input terminal of the attenuation circuit, the output terminal of the attenuation circuit is connected to the input terminal of the instrumentation amplifier circuit, and the gain adjustment circuit is connected to the instrumentation amplifier circuit.

[0006] The gain adjustment circuit includes an analog electronic switch, which is connected to the main control MCU circuit and the instrumentation amplifier circuit respectively.

[0007] Furthermore, the gain adjustment circuit includes an analog electronic switch U1, resistors R1, R2, R5, and R6.

[0008] Pin 10 of the analog electronic switch U1 is connected to the first end of the resistor R1;

[0009] Pin 11 of the analog electronic switch U1 is connected to the first end of the resistor R5;

[0010] The second end of resistor R1 is connected to the second end of resistor R5;

[0011] Pin 5 of the analog electronic switch U1 is connected to the first end of the resistor R2;

[0012] Pin 4 of the analog electronic switch U1 is connected to the first end of the resistor R6;

[0013] The second end of resistor R2 is connected to the second end of resistor R6.

[0014] Furthermore, the model number of the analog electronic switch U1 is ADG1404YRUZ.

[0015] Furthermore, the isolated step-down circuit includes an optocoupler.

[0016] Furthermore, the attenuation circuit includes RF connector J1, RF connector J2, resistors R12, R13, R4, R9, and R14, a sliding rheostat R15, R18, R19, R20, R22, R25, R27, and R23, a sliding rheostat R29, and R30, and capacitors C3, C4, C2, C5, C10, C11, C12, C13, and C14.

[0017] The RF connector J1 is connected to the first end of the resistor R12 and the first end of the capacitor C3.

[0018] The second end of resistor R12, the second end of capacitor C3, the first end of resistor R13, and the first end of capacitor C4 are connected to each other.

[0019] The second end of resistor R13, the second end of capacitor C4, the first end of capacitor C2, the first end of capacitor C5, and the first end of resistor R14 are connected to each other.

[0020] The second terminal of capacitor C2 is connected to the first terminal of resistor R4;

[0021] The second terminal of capacitor C5 is connected to the first terminal of resistor R9;

[0022] The second end of the resistor R14 is connected to the first end of the sliding rheostat R15;

[0023] The RF connector J2 is connected to the first end of the resistor R18 and the first end of the capacitor C10.

[0024] The second end of resistor R18, the second end of capacitor C10, the first end of resistor R19, and the first end of capacitor C11 are connected to each other.

[0025] The second terminal of resistor R19, the second terminal of capacitor C11, the first terminal of capacitor C12, the first terminal of capacitor C13, the first terminal of resistor R20, and the first terminal of resistor R27 are connected to each other.

[0026] The second terminal of capacitor C12 is connected to the first terminal of resistor R22;

[0027] The second terminal of capacitor C13 is connected to the first terminal of resistor R25;

[0028] The second end of the resistor R20 is connected to the second end of the sliding rheostat R15;

[0029] The second end of resistor R4, the second end of resistor R9, the second end of resistor R22, the second end of resistor R25, and the first end of capacitor C14 are connected to the sliding end of the sliding rheostat R15 and to the analog ground.

[0030] The second end of the resistor R27 and the second end of the capacitor C14 are connected to the sliding end of the sliding rheostat R29;

[0031] The first end of the sliding rheostat R29 is connected to the first end of the resistor R23;

[0032] The second end of the sliding rheostat R29 is connected to the first end of the resistor R30.

[0033] Furthermore, the instrumentation amplifier circuit includes operational amplifier U2, operational amplifier U5, operational amplifier U4, amplifier U3, switching diode D1, switching diode D2, switching diode D3, resistor R7, resistor R17, resistor R10, capacitor C7, resistor R28, resistor R21, resistor R26, capacitor C8, resistor R8, capacitor C1, resistor R3, resistor R11, capacitor C6, resistor R24, capacitor C15, resistor R16, and capacitor C9;

[0034] The common terminal of the switching diode D1 is connected to the first terminal of the resistor R7;

[0035] The second end of the resistor R7 is connected to the positive input terminal of the operational amplifier U2;

[0036] The first terminal of capacitor C7 and the first terminal of resistor R17 are connected to the negative input terminal of operational amplifier U2, and are also connected to the gain adjustment circuit.

[0037] The second terminal of capacitor C7, the second terminal of resistor R17, and the first terminal of resistor R10 are connected to the output terminal of operational amplifier U2.

[0038] The common terminal of the switching diode D3 is connected to the first terminal of the resistor R28;

[0039] The second end of the resistor R28 is connected to the positive input terminal of the operational amplifier U5;

[0040] The first terminal of capacitor C8 and the first terminal of resistor R21 are connected to the negative input terminal of operational amplifier U5, and are also connected to the gain adjustment circuit.

[0041] The second terminal of capacitor C8, the second terminal of resistor R21, and the first terminal of resistor R26 are connected to the output terminal of operational amplifier U5.

[0042] The second end of resistor R10 and the first end of resistor R8 are connected to the positive input terminal of operational amplifier U4;

[0043] The second end of resistor R8, the first end of capacitor C1, the first end of resistor R11, and the first end of capacitor C6 are connected to the output terminal of amplifier U3.

[0044] The first end of the resistor R13 is connected to the positive input terminal of the amplifier U3;

[0045] The second end of resistor R11 and the second end of capacitor C6 are connected to the negative input terminal of amplifier U3;

[0046] The second terminal of capacitor C11 is connected to the second terminal of resistor R3;

[0047] The second end of resistor R26, the first end of resistor R24, and the first end of capacitor C15 are connected to the negative input terminal of operational amplifier U5.

[0048] The second end of resistor R24 ​​and the second end of capacitor C15 are connected to the output end of operational amplifier U5, and are also connected to the first end of resistor R16 and the first end of capacitor C9.

[0049] The second end of resistor R16 and the second end of capacitor C9 are connected to the common terminal of switching diode D2.

[0050] Furthermore, the main control MCU circuit includes a main control MCU chip, the model of which is STM32H723VGH6.

[0051] Furthermore, the high-voltage power equipment monitoring circuit also includes a level-up circuit, the input of which is connected to the output of the instrument amplifier circuit.

[0052] Furthermore, the level-up circuit includes a level-up chip U23, capacitor C126, and capacitor C149;

[0053] Pins 1 and 2 of the level-up chip U23 are connected to the first terminal of the capacitor C126;

[0054] Pins 4 and 5 of the level-up chip U23 are connected to the second terminal of the capacitor C126 and then connected to the analog ground terminal;

[0055] Pin 9 of the level-up chip U23 is connected to the first terminal of the capacitor C149;

[0056] The level-up chip U23 is model AD5683RBRMZ-3-RL7.

[0057] Furthermore, the high-voltage power equipment monitoring circuit also includes a communication circuit, which is connected to the main control MCU circuit.

[0058] This invention provides a high-voltage power equipment monitoring circuit, offering a monitoring circuit scheme that simultaneously incorporates an attenuation circuit and an instrumentation amplifier circuit. The attenuation circuit reduces the input high-voltage signal to a low-voltage signal, effectively protecting the circuit's downstream structure from high-voltage damage. The instrumentation amplifier circuit then performs preliminary amplification of the attenuated low-voltage signal, effectively suppressing common-mode interference signals through a differential input structure, thus improving the monitoring accuracy of the high-voltage signal. An isolation step-down circuit is included for protection, enhancing monitoring safety and stability. Furthermore, the gain of the instrumentation amplifier circuit can be adjusted in real-time via an analog electronic switch in the gain adjustment circuit, achieving high high-voltage signal monitoring accuracy. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a circuit module architecture diagram of the high-voltage power equipment monitoring circuit in this embodiment of the present invention;

[0061] Figure 2 This is a circuit diagram of the attenuation circuit in an embodiment of this utility model;

[0062] Figure 3 This is a circuit diagram of the instrument amplification circuit in an embodiment of this utility model;

[0063] Figure 4 This is a circuit diagram of the main control MCU circuit in an embodiment of this utility model;

[0064] Figure 5 This is a circuit diagram of the gain adjustment circuit in an embodiment of this utility model;

[0065] Figure 6 This is a circuit diagram of the level-up circuit in an embodiment of this utility model. Detailed Implementation

[0066] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0067] In this invention, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, actions, components, portions or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, actions, components, portions or combinations thereof.

[0068] It should also be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0069] This utility model embodiment provides a high-voltage power equipment detection circuit, which includes a main control MCU circuit, an isolation step-down circuit, an attenuation circuit, an instrumentation amplifier circuit, and a gain adjustment circuit;

[0070] The main control MCU circuit is connected to the isolation step-down circuit, the attenuation circuit, and the instrumentation amplifier circuit respectively. The input terminal of the isolation step-down circuit is connected to the input voltage, the output terminal of the isolation step-down circuit is connected to the input terminal of the attenuation circuit, the output terminal of the attenuation circuit is connected to the input terminal of the instrumentation amplifier circuit, and the gain adjustment circuit is connected to the instrumentation amplifier circuit.

[0071] The gain adjustment circuit includes an analog electronic switch, which is connected to the main control MCU circuit and the instrumentation amplifier circuit respectively.

[0072] In one optional implementation of this embodiment, such as Figure 1 As shown, Figure 1The diagram shows the circuit module architecture of the high-voltage power equipment monitoring circuit in an embodiment of the present invention. The high-voltage power equipment monitoring circuit includes a main control MCU circuit, an isolation step-down circuit, an attenuation circuit, an instrumentation amplifier circuit, and a gain adjustment circuit.

[0073] The main control MCU circuit is connected to the isolation step-down circuit, the attenuation circuit, and the instrumentation amplifier circuit respectively. The input terminal of the isolation step-down circuit is connected to the input voltage, the output terminal of the isolation step-down circuit is connected to the input terminal of the attenuation circuit, the output terminal of the attenuation circuit is connected to the input terminal of the instrumentation amplifier circuit, and the gain adjustment circuit is connected to the instrumentation amplifier circuit.

[0074] The gain adjustment circuit includes an analog electronic switch, which is connected to the main control MCU circuit and the instrumentation amplifier circuit respectively.

[0075] In an optional implementation of this embodiment, the isolated step-down circuit includes an optocoupler.

[0076] Specifically, the isolation step-down circuit is used to isolate and step down external high-voltage signals for internal circuit power supply. It includes several optocouplers, which achieve electrical isolation and improve the safety and stability of the circuit.

[0077] In one optional implementation of this embodiment, such as Figure 2 As shown, Figure 2 The circuit diagram of the attenuation circuit in an embodiment of the present invention is shown. The attenuation circuit includes RF connector J1, RF connector J2, resistors R12, R13, R4, R9, and R14, sliding rheostats R15, R18, R19, R20, R22, R25, R27, and R23, sliding rheostats R29 and R30, and capacitors C3, C4, C2, C5, C10, C11, C12, C13, and C14.

[0078] The RF connector J1 is connected to the first end of the resistor R12 and the first end of the capacitor C3.

[0079] The second end of resistor R12, the second end of capacitor C3, the first end of resistor R13, and the first end of capacitor C4 are connected to each other.

[0080] The second end of resistor R13, the second end of capacitor C4, the first end of capacitor C2, the first end of capacitor C5, and the first end of resistor R14 are connected to each other.

[0081] The second terminal of capacitor C2 is connected to the first terminal of resistor R4;

[0082] The second terminal of capacitor C5 is connected to the first terminal of resistor R9;

[0083] The second end of the resistor R14 is connected to the first end of the sliding rheostat R15;

[0084] The RF connector J2 is connected to the first end of the resistor R18 and the first end of the capacitor C10.

[0085] The second end of resistor R18, the second end of capacitor C10, the first end of resistor R19, and the first end of capacitor C11 are connected to each other.

[0086] The second terminal of resistor R19, the second terminal of capacitor C11, the first terminal of capacitor C12, the first terminal of capacitor C13, the first terminal of resistor R20, and the first terminal of resistor R27 are connected to each other.

[0087] The second terminal of capacitor C12 is connected to the first terminal of resistor R22;

[0088] The second terminal of capacitor C13 is connected to the first terminal of resistor R25;

[0089] The second end of the resistor R20 is connected to the second end of the sliding rheostat R15;

[0090] The second end of resistor R4, the second end of resistor R9, the second end of resistor R22, the second end of resistor R25, and the first end of capacitor C14 are connected to the sliding end of the sliding rheostat R15 and to the analog ground.

[0091] The second end of the resistor R27 and the second end of the capacitor C14 are connected to the sliding end of the sliding rheostat R29;

[0092] The first end of the sliding rheostat R29 is connected to the first end of the resistor R23;

[0093] The second end of the sliding rheostat R29 is connected to the first end of the resistor R30.

[0094] Specifically, the attenuation circuit can be regarded as a two-way attenuation circuit, which is connected to the input voltage through two RF connectors respectively. After passing through each voltage divider resistor, the voltage is attenuated by voltage division. The attenuation factor of the attenuation circuit can be controlled by adjusting the resistance values ​​of the sliding rheostats R15 and R29.

[0095] Furthermore, the resistance values ​​of resistors R12 and R18 are 10MΩ, the resistance values ​​of resistors R13 and R19 are 316KΩ, the resistance values ​​of resistors R4, R9, R22, and R25 are 10Ω, the resistance values ​​of resistors R14 and R20 are 16.9KΩ, the resistance values ​​of resistors R23 and R30 are 100Ω, the resistance values ​​of sliding rheostats R15 and R29 are 1KΩ, the resistance value of resistor R27 is 330KΩ, the capacitance values ​​of capacitors C3, C4, C10, and C11 are 2pF, the capacitance values ​​of capacitors C2 and C12 are 68pF, the capacitance values ​​of capacitors C5 and C13 are 100pF, and the capacitance value of capacitor C14 is 100nF.

[0096] It should be noted that, in this embodiment, the attenuation factor of the attenuation circuit can reach 600 times.

[0097] In an optional implementation of this embodiment, the working principle of the attenuation circuit includes:

[0098] RF connectors J1 and J2 serve as high-voltage signal input terminals, each receiving one high-voltage signal. Figure 2 The “HV IN1+” and “HV IN1-” in the circuit are attenuated by the voltage divider resistor network. Finally, after the voltage difference between the two high-voltage signals reaches the required level, the attenuated low-voltage signal is output to the next stage circuit.

[0099] The resistors form a voltage divider network, where resistors R12, R13, R18 and R19 constitute the first-stage voltage divider network, which initially reduces the voltage using the principle of "large resistor voltage division". Resistors R4, R9, R22 and R25 construct the secondary voltage divider network, which further attenuates the voltage to a low voltage range.

[0100] Capacitors C3, C4, C10, and C11 are used to suppress high-frequency interference; capacitors C2, C12, C5, and C13 are used to filter out intermediate-frequency interference; and capacitor C14 is used to filter out low-frequency interference to avoid noise interference.

[0101] It should be noted that when the two high-voltage signals are processed by the voltage divider resistor network of the attenuation circuit and then input to the next stage instrumentation amplifier circuit, the parameter errors of electronic components (such as resistor accuracy deviation, capacitor value difference, etc.) may cause the voltage division ratio of the two signals to be inconsistent, introducing common-mode error. Here, two sliding rheostats R15 and R29 are set to finely adjust the resistance value connected to the circuit, which can compensate for the asymmetry of the two signals, so that the voltage division ratio of the two signals is consistent. This ensures that only the differential signal (i.e., the target monitoring signal) is effectively amplified when the instrumentation amplifier circuit performs differential amplification, maximizing the suppression of common-mode interference and improving the monitoring and measurement accuracy of the circuit.

[0102] In one optional implementation of this embodiment, such as Figure 3 As shown, Figure 3 The circuit diagram of the instrumentation amplifier circuit in an embodiment of the present invention is shown. The instrumentation amplifier circuit includes operational amplifier U2, operational amplifier U5, operational amplifier U4, amplifier U3, switching diode D1, switching diode D2, switching diode D3, resistor R7, resistor R17, resistor R10, capacitor C7, resistor R28, resistor R21, resistor R26, capacitor C8, resistor R8, capacitor C1, resistor R3, resistor R11, capacitor C6, resistor R24, capacitor C15, resistor R16 and capacitor C9.

[0103] The common terminal of the switching diode D1 is connected to the first terminal of the resistor R7;

[0104] The second end of the resistor R7 is connected to the positive input terminal of the operational amplifier U2;

[0105] The first terminal of capacitor C7 and the first terminal of resistor R17 are connected to the negative input terminal of operational amplifier U2, and are also connected to the gain adjustment circuit.

[0106] The second terminal of capacitor C7, the second terminal of resistor R17, and the first terminal of resistor R10 are connected to the output terminal of operational amplifier U2.

[0107] The common terminal of the switching diode D3 is connected to the first terminal of the resistor R28;

[0108] The second end of the resistor R28 is connected to the positive input terminal of the operational amplifier U5;

[0109] The first terminal of capacitor C8 and the first terminal of resistor R21 are connected to the negative input terminal of operational amplifier U5, and are also connected to the gain adjustment circuit.

[0110] The second terminal of capacitor C8, the second terminal of resistor R21, and the first terminal of resistor R26 are connected to the output terminal of operational amplifier U5.

[0111] The second end of resistor R10 and the first end of resistor R8 are connected to the positive input terminal of operational amplifier U4;

[0112] The second end of resistor R8, the first end of capacitor C1, the first end of resistor R11, and the first end of capacitor C6 are connected to the output terminal of amplifier U3.

[0113] The first end of the resistor R13 is connected to the positive input terminal of the amplifier U3;

[0114] The second end of resistor R11 and the second end of capacitor C6 are connected to the negative input terminal of amplifier U3;

[0115] The second terminal of capacitor C11 is connected to the second terminal of resistor R3;

[0116] The second end of resistor R26, the first end of resistor R24, and the first end of capacitor C15 are connected to the negative input terminal of operational amplifier U5.

[0117] The second end of resistor R24 ​​and the second end of capacitor C15 are connected to the output end of operational amplifier U5, and are also connected to the first end of resistor R16 and the first end of capacitor C9.

[0118] The second end of resistor R16 and the second end of capacitor C9 are connected to the common terminal of switching diode D2.

[0119] Specifically, the instrument amplifier circuit can also be regarded as a two-way amplification, corresponding to the two-way attenuation of the attenuation circuit.

[0120] Furthermore, the operational amplifiers U2, U4, and U5 are model ADA4817-1ACPZ-R7, the switching diodes D1, D2, and D3 are model BAV99 dual series switching diodes, the resistors R7 and R28 have a resistance of 10Ω, the resistors R17 and R21 have a resistance of 1KΩ, the capacitors C7 and C8 have a capacitance of 820pF, the resistors R10, R26, R8, and R24 have a resistance of 1KΩ, the resistor R3 has a resistance of 100KΩ, the resistor R11 has a resistance of 200KΩ, the resistor R16 has a resistance of 50Ω, the capacitor C1 has a capacitance of 2.2µF, the capacitor C6 has a capacitance of 10nF, the capacitor C15 has a capacitance of 10pF, and the capacitor C9 has a capacitance of 2.2pF.

[0121] In an optional implementation of this embodiment, the instrument amplification circuit is provided with a power supply filter circuit, which includes several capacitors connected in parallel with the same capacitance value. One end of each capacitor is connected to the input power supply, and the other end is grounded.

[0122] In an optional implementation of this embodiment, the working principle of the instrumentation amplifier circuit includes:

[0123] Operational amplifiers U2, U5, and U4 form a three-op-amp instrumentation amplifier circuit consisting of "two input stage op-amps + one output stage op-amp". U2 and U5 are input stage differential amplifier units, responsible for the initial amplification of the attenuated low-voltage input signal, providing high input impedance and common-mode rejection capability. U4 is the output stage differential-to-single-ended unit, which converts the differential signal output from U2 and U5 into a single-ended signal, and further amplifies and conditions the signal to meet the ADC acquisition requirements of the subsequent main control MCU circuit.

[0124] In the input stage of this circuit, the cooperative amplifier circuit of U2 and U5, the relationship between the various components and U2 and U5 includes:

[0125] Input protection: Switching diode D1 is connected to the positive input terminal of U2 through resistor R7, and switching diode D3 is connected to the positive input terminal of U5 through resistor R28. D1 and D3 conduct when the signal is overvoltaged, clamping the input voltage to ±0.7V (forward voltage drop of silicon diode), protecting U2 and U5 from damage by high voltage. Resistors R7 and R28 are current-limiting resistors, reducing the conduction current during overvoltage, which also serves to protect U2 and U5.

[0126] Differential Amplification and Feedback: The negative input terminal of U2 is connected to the resistor network of the analog electronic switch U1 in the subsequent gain adjustment circuit, and is connected to its own output terminal through resistor R17 and capacitor C7 to form a negative feedback network. R17 is the feedback resistor, which, together with the resistor connected in the gain adjustment circuit, determines the amplification factor of U2. C7 is used for phase compensation to avoid circuit self-oscillation. The negative feedback network of U5 is the same as that of U2. The negative input terminal of U5 is connected to its own output terminal through resistor R21 and capacitor C8 to form a negative feedback network. The parameters and functions of resistor R21 and capacitor C8 are the same as those of resistor R17 and capacitor C7, respectively, to ensure that the amplification characteristics of U2 and U5 are symmetrical and to enhance the common-mode rejection ratio.

[0127] Signal transmission: The output terminal of U2 is connected to the positive input terminal of U4 through resistor R10, and the output terminal of U5 is connected to the negative input terminal of U4 through resistor R26, thus transmitting the differential signal to the output stage.

[0128] In the output stage of this circuit, including the differential-to-single-ended converter U4 and signal conditioning, the relationships between the various components and U4 are as follows:

[0129] Differential to single-ended conversion: The positive input terminal of U4 receives the output signal of U2, and the negative input terminal receives the output signal of U5. The difference between the two signals is converted into a single-ended signal output through differential amplification, while suppressing common-mode signal interference.

[0130] Gain and feedback adjustment: The negative input terminal of U4 is connected to its own output terminal through resistor R24 ​​to form a closed-loop feedback. Resistor R11 and capacitor C6 are connected in parallel in the feedback loop of U4. R11 is used to further increase the amplification factor, and C6 is used to filter out high-frequency noise to ensure a smooth output signal.

[0131] Level boosting coordination: One end of resistor R3 is connected to the input link of U4, and the other end is connected to an external reference level. The signal level is boosted by the amplification characteristics of U4, so that the circuit can measure positive and negative voltages (such as shifting the negative voltage signal to the positive range that the ADC can collect).

[0132] The synergistic effects of peripheral components include:

[0133] Capacitor C1 is connected in parallel between the output terminal of U4 and ground for filtering and interference suppression;

[0134] Capacitors C7 and C8 serve as phase compensation capacitors for U2 and U5, used to filter out low-frequency interference and prevent high-frequency self-oscillation;

[0135] Capacitors C15 and C9 are used for high-frequency filtering at the output terminal of U5 and the total output terminal of the instrumentation amplifier circuit, respectively.

[0136] Switching diode D2 is connected to the total output terminal to prevent reverse voltage surges in the downstream circuit; resistor R16 and capacitor C9 match the output impedance to avoid signal transmission reflection.

[0137] The relationship between the gain adjustment circuit and the main control MCU circuit:

[0138] The single-ended signal output from U4 is filtered and protected before being input to the ADC pin of the MCU. The ADC acquires the signal, and by combining the gain factor and the attenuation ratio of the attenuation circuit, the amplitude of the original high-voltage signal is calculated to complete the monitoring.

[0139] In one optional implementation of this embodiment, such as Figure 4 As shown, Figure 4 The circuit diagram of the main control MCU circuit in this embodiment of the present invention is shown. The main control MCU circuit includes a main control MCU chip, and the main control MCU chip is model STM32H723VGH6.

[0140] Specifically, the main control MCU circuit includes a voltage acquisition ADC for controlling the operation of the entire high-voltage power equipment monitoring circuit.

[0141] In one optional implementation of this embodiment, such as Figure 5 As shown, Figure 5 The circuit diagram of the gain adjustment circuit in the embodiment of the present invention is shown. The gain adjustment circuit includes an analog electronic switch U1, resistor R1, resistor R2, resistor R5 and resistor R6.

[0142] Pin 10 of the analog electronic switch U1 is connected to the first end of the resistor R1;

[0143] Pin 11 of the analog electronic switch U1 is connected to the first end of the resistor R5;

[0144] The second end of resistor R1 is connected to the second end of resistor R5;

[0145] Pin 5 of the analog electronic switch U1 is connected to the first end of the resistor R2;

[0146] Pin 4 of the analog electronic switch U1 is connected to the first end of the resistor R6;

[0147] The second end of resistor R2 is connected to the second end of resistor R6.

[0148] Specifically, the model number of the analog electronic switch U1 is ADG1404YRUZ.

[0149] Furthermore, the resistance value of resistor R1 is 1K, the resistance value of resistor R2 is 249R, the resistance value of resistor R5 is 499R, and the resistance value of resistor R6 is 24R.

[0150] Furthermore, the analog electronic switch U1 in the gain adjustment circuit, based on the control of the main control MCU circuit, can automatically switch the gain amplification factor to adapt to different ADC ranges.

[0151] It should be noted that the analog electronic switch in the gain adjustment circuit can be replaced by a digital potentiometer, but in the preferred case, an analog electronic switch is selected.

[0152] In an optional implementation of this embodiment, the high-voltage power equipment monitoring circuit further includes a level-up circuit, the input of which is connected to the output of the instrumentation amplifier circuit.

[0153] Specifically, such as Figure 6 As shown, Figure 6 The circuit diagram of the level-up circuit in the embodiment of this utility model is shown. The level-up circuit is a DAC circuit and includes a level-up chip U23, capacitor C126, and capacitor C149.

[0154] Pins 1 and 2 of the level-up chip U23 are connected to the first terminal of the capacitor C126;

[0155] Pins 4 and 5 of the level-up chip U23 are connected to the second terminal of the capacitor C126 and then connected to the analog ground terminal;

[0156] Pin 9 of the level-up chip U23 is connected to the first terminal of the capacitor C149.

[0157] Furthermore, the model number of the level-up chip U23 is AD5683RBRMZ-3-RL7.

[0158] Furthermore, the capacitance value of capacitor C126 is 0.1uF, and the capacitance value of capacitor C149 is 100nF.

[0159] In an optional implementation of this embodiment, the working principle of the gain adjustment circuit includes:

[0160] The gain adjustment circuit achieves dynamic adjustment of the gain factor through "analog electronic switch switching + resistor network matching". The core component matching relationship and adjustment principle are as follows:

[0161] Analog electronic switch U1 (ADG1404YRUZ): a four-channel single-pole single-throw switch. Pins 10, 11, 5, and 4 are connected to resistors R1, R5, R2, and R6 respectively. The pins are controlled by MCU control signals (high and low levels) to turn the channel on / off.

[0162] R1 and R5 are connected in series (common terminal connected to analog ground), and R2 and R6 are connected in series (common terminal connected to analog ground) to form two sets of switchable feedback resistor branches, which are connected to the feedback loop of the instrumentation amplifier circuit.

[0163] The gain formula for the instrument amplifier circuit is: G = 1 + 2(Rf / Rq), where Rf is the feedback resistor with a resistance value of 1K, and Rq is the gain adjustment resistor. When pin 10 of U1 is on and resistor R1 is connected, the gain is 3 times; when pin 11 of U1 is on and resistor R5 is connected, the gain is 5 times; when pin 5 of U1 is on and resistor R2 is connected, the gain is 9 times; when pin 4 of U1 is on and resistor R6 is connected, the gain is 84 times.

[0164] The main control MCU circuit outputs a control signal to the control pin of U1 based on the amplitude of the attenuated low-voltage signal acquired and judged by the ADC. By selecting different pins to turn on and switching the gain adjustment resistor value, the gain of the instrument amplifier circuit can be adjusted to ensure that the signal is input to the ADC at full scale and avoid range overflow or insufficient resolution.

[0165] In an optional implementation of this embodiment, the high-voltage power equipment monitoring circuit further includes a communication circuit, which is connected to the main control MCU circuit.

[0166] Specifically, the communication circuit is a 422 communication circuit.

[0167] Working principle: The main control MCU circuit controls the isolation step-down circuit, attenuation circuit, instrumentation amplifier circuit, gain adjustment circuit, and level boosting circuit.

[0168] In this embodiment, the high-voltage power equipment monitoring circuit is connected to a high-voltage signal and is electrically isolated by an optocoupler in the isolation step-down circuit.

[0169] The high-voltage signal is then connected to the two high-voltage acquisition terminals of the attenuation circuit, i.e., the RF connector. After being attenuated by the voltage divider resistor in the attenuation circuit, the high-voltage signal is prevented from directly entering the subsequent circuit.

[0170] The attenuated low-voltage signal is fed into the instrument amplifier circuit. While amplifying the gain, it suppresses common-mode interference signals through the differential input structure and can measure positive and negative voltages. It has high input impedance and can measure the voltage difference between any two points.

[0171] When the instrument amplifier circuit performs gain amplification processing on the attenuated low-voltage signal, the ADC built into the main control MCU chip in the main control MCU circuit acquires the attenuated low-voltage signal. When the acquired low-voltage signal is too small or too large, the main control MCU circuit controls the gain adjustment circuit to adjust the gain of the instrument amplifier circuit according to the magnitude of the low-voltage signal. The specific adjustment process is achieved by the analog electronic switch set in the gain adjustment circuit. By switching the analog electronic switch, the gain amplification factor of the instrument amplifier circuit is adjusted to adapt to different ranges.

[0172] After the low-voltage signal is amplified by the instrument amplifier circuit, the ADC in the main control MCU chip of the main control MCU circuit completes the sampling and controls the level rise circuit to raise the amplitude of the low-voltage signal so that it is adjusted to the voltage range that the ADC can collect.

[0173] When the main control MCU circuit processes data, it transmits the monitoring results to the outside world through the communication circuit.

[0174] In this embodiment, the gain adjustment circuit switches the gain amplification factor of the instrument amplifier circuit through an analog electronic switch, which can adapt to a wide range of high voltage signals. The circuit realizes automatic gain adjustment to ensure that signals under different attenuation factors can be input to the ADC at full scale, improving the resolution by more than 30% and effectively improving the monitoring accuracy.

[0175] In summary, this utility model embodiment proposes a high-voltage power equipment monitoring circuit, providing a monitoring circuit scheme that simultaneously incorporates an attenuation circuit and an instrumentation amplification circuit. The attenuation circuit attenuates the input high-voltage signal to a low-voltage signal, effectively protecting the downstream structure of the circuit from high-voltage damage. The instrumentation amplification circuit then performs preliminary amplification of the attenuated low-voltage signal, effectively suppressing common-mode interference signals through a differential input structure, thereby improving the monitoring accuracy of the high-voltage signal. An isolation step-down circuit is included for protection, enhancing monitoring safety and stability. Furthermore, the gain of the instrumentation amplification circuit can be adjusted in real-time via an analog electronic switch in the gain adjustment circuit, achieving high high-voltage signal monitoring accuracy.

[0176] The above provides a detailed description of a high-voltage power equipment monitoring circuit provided by the embodiments of this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A high-voltage power equipment monitoring circuit, characterized in that, The high-voltage power equipment monitoring circuit includes a main control MCU circuit, an isolation step-down circuit, an attenuation circuit, an instrumentation amplifier circuit, and a gain adjustment circuit. The main control MCU circuit is connected to the isolation step-down circuit, the attenuation circuit, and the instrumentation amplifier circuit respectively. The input terminal of the isolation step-down circuit is connected to the input voltage, the output terminal of the isolation step-down circuit is connected to the input terminal of the attenuation circuit, the output terminal of the attenuation circuit is connected to the input terminal of the instrumentation amplifier circuit, and the gain adjustment circuit is connected to the instrumentation amplifier circuit. The gain adjustment circuit includes an analog electronic switch, which is connected to the main control MCU circuit and the instrumentation amplifier circuit respectively.

2. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The gain adjustment circuit includes an analog electronic switch U1, resistors R1, R2, R5, and R6. Pin 10 of the analog electronic switch U1 is connected to the first end of the resistor R1; Pin 11 of the analog electronic switch U1 is connected to the first end of the resistor R5; The second end of resistor R1 is connected to the second end of resistor R5; Pin 5 of the analog electronic switch U1 is connected to the first end of the resistor R2; Pin 4 of the analog electronic switch U1 is connected to the first end of the resistor R6; The second end of resistor R2 is connected to the second end of resistor R6.

3. The high-voltage power equipment monitoring circuit as described in claim 2, characterized in that, The model number of the analog electronic switch U1 is ADG1404YRUZ.

4. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The isolated step-down circuit includes an optocoupler.

5. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The attenuation circuit includes RF connector J1, RF connector J2, resistors R12, R13, R4, R9, and R14, a sliding rheostat R15, R18, R19, R20, R22, R25, R27, and R23, a sliding rheostat R29, and R30, and capacitors C3, C4, C2, C5, C10, C11, C12, C13, and C14. The RF connector J1 is connected to the first end of the resistor R12 and the first end of the capacitor C3. The second end of resistor R12, the second end of capacitor C3, the first end of resistor R13, and the first end of capacitor C4 are connected to each other. The second end of resistor R13, the second end of capacitor C4, the first end of capacitor C2, the first end of capacitor C5, and the first end of resistor R14 are connected to each other. The second terminal of capacitor C2 is connected to the first terminal of resistor R4; The second terminal of capacitor C5 is connected to the first terminal of resistor R9; The second end of the resistor R14 is connected to the first end of the sliding rheostat R15; The RF connector J2 is connected to the first end of the resistor R18 and the first end of the capacitor C10. The second end of resistor R18, the second end of capacitor C10, the first end of resistor R19, and the first end of capacitor C11 are connected to each other. The second terminal of resistor R19, the second terminal of capacitor C11, the first terminal of capacitor C12, the first terminal of capacitor C13, the first terminal of resistor R20, and the first terminal of resistor R27 are connected to each other. The second terminal of capacitor C12 is connected to the first terminal of resistor R22; The second terminal of capacitor C13 is connected to the first terminal of resistor R25; The second end of the resistor R20 is connected to the second end of the sliding rheostat R15; The second end of resistor R4, the second end of resistor R9, the second end of resistor R22, the second end of resistor R25, and the first end of capacitor C14 are connected to the sliding end of the sliding rheostat R15 and to the analog ground. The second end of the resistor R27 and the second end of the capacitor C14 are connected to the sliding end of the sliding rheostat R29; The first end of the sliding rheostat R29 is connected to the first end of the resistor R23; The second end of the sliding rheostat R29 is connected to the first end of the resistor R30.

6. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The instrument amplifier circuit includes operational amplifier U2, operational amplifier U5, operational amplifier U4, amplifier U3, switching diode D1, switching diode D2, switching diode D3, resistor R7, resistor R17, resistor R10, capacitor C7, resistor R28, resistor R21, resistor R26, capacitor C8, resistor R8, capacitor C1, resistor R3, resistor R11, capacitor C6, resistor R24, capacitor C15, resistor R16 and capacitor C9; The common terminal of the switching diode D1 is connected to the first terminal of the resistor R7; The second end of the resistor R7 is connected to the positive input terminal of the operational amplifier U2; The first terminal of capacitor C7 and the first terminal of resistor R17 are connected to the negative input terminal of operational amplifier U2, and are also connected to the gain adjustment circuit. The second terminal of capacitor C7, the second terminal of resistor R17, and the first terminal of resistor R10 are connected to the output terminal of operational amplifier U2. The common terminal of the switching diode D3 is connected to the first terminal of the resistor R28; The second end of the resistor R28 is connected to the positive input terminal of the operational amplifier U5; The first terminal of capacitor C8 and the first terminal of resistor R21 are connected to the negative input terminal of operational amplifier U5, and are also connected to the gain adjustment circuit. The second terminal of capacitor C8, the second terminal of resistor R21, and the first terminal of resistor R26 are connected to the output terminal of operational amplifier U5. The second end of resistor R10 and the first end of resistor R8 are connected to the positive input terminal of operational amplifier U4; The second end of resistor R8, the first end of capacitor C1, the first end of resistor R11, and the first end of capacitor C6 are connected to the output terminal of amplifier U3. The first end of the resistor R13 is connected to the positive input terminal of the amplifier U3; The second end of resistor R11 and the second end of capacitor C6 are connected to the negative input terminal of amplifier U3; The second terminal of capacitor C11 is connected to the second terminal of resistor R3; The second end of resistor R26, the first end of resistor R24, and the first end of capacitor C15 are connected to the negative input terminal of operational amplifier U5. The second end of resistor R24 ​​and the second end of capacitor C15 are connected to the output end of operational amplifier U5, and are also connected to the first end of resistor R16 and the first end of capacitor C9. The second end of resistor R16 and the second end of capacitor C9 are connected to the common terminal of switching diode D2.

7. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The main control MCU circuit includes a main control MCU chip, the model of which is STM32H723VGH6.

8. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The high-voltage power equipment monitoring circuit also includes a level-up circuit, the input of which is connected to the output of the instrumentation amplifier circuit.

9. The high-voltage power equipment monitoring circuit as described in claim 8, characterized in that, The level-up circuit includes a level-up chip U23, capacitor C126, and capacitor C149. Pins 1 and 2 of the level-up chip U23 are connected to the first terminal of the capacitor C126; Pins 4 and 5 of the level-up chip U23 are connected to the second terminal of the capacitor C126 and then connected to the analog ground terminal; Pin 9 of the level-up chip U23 is connected to the first terminal of the capacitor C149; The level-up chip U23 is model AD5683RBRMZ-3-RL7.

10. The high-voltage power equipment monitoring circuit as described in claim 1, characterized in that, The high-voltage power equipment monitoring circuit also includes a communication circuit, which is connected to the main control MCU circuit.

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