High-voltage AC voltage acquisition circuit

Abstract

The present invention discloses a high-voltage AC voltage acquisition circuit, comprising a filter circuit, a current acquisition circuit, a voltage conversion circuit, and an A / D conversion circuit, which are connected in sequence. The filter circuit is used to filter out clutter and eliminate differential-mode interference between input signals and common-mode interference between the input and the circuit ground. The current acquisition circuit is connected in parallel between the input lines of the high voltage to be measured, collects and isolates the high-voltage signal, and converts the high-voltage signal into a current signal. The voltage conversion circuit is used to convert the current signal into a low-voltage signal. The A / D conversion circuit is used to convert the low-voltage signal into a digital signal. This voltage acquisition circuit has high precision, good linearity, and fast response, improving the safety of the power system and reducing interference caused by external high-voltage signals.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage acquisition, and more specifically, to a high-voltage AC voltage acquisition circuit. Background Art

[0002] In power collection systems, it is often necessary to collect AC voltages of several thousand volts. The traditional high-voltage collection method mainly uses a resistor divider circuit. Its disadvantage is that the high-voltage signal is directly introduced into the system after voltage division. This collection method is not only unsafe, but also poses a great safety hazard to personnel and equipment. In addition, the interference carried by the external high-voltage signal will be introduced into the system, causing interference to the entire collection system. At the same time, the voltage divider resistor itself has errors such as accuracy and temperature drift, which will have a significant impact on the detection accuracy.

[0003] Therefore, a high-voltage AC voltage acquisition circuit with high precision and good safety is needed. Summary of the Invention

[0004] In order to solve the problems of poor safety and poor accuracy of existing high-voltage AC voltage acquisition methods, the present invention innovatively provides a high-voltage AC voltage acquisition circuit with high accuracy, good linearity and fast response.

[0005] To achieve the above technical objectives, the present invention discloses a high-voltage AC voltage acquisition circuit, comprising a filter circuit, a current acquisition circuit, a voltage conversion circuit, and an A / D conversion circuit, wherein the filter circuit, current acquisition circuit, voltage conversion circuit, and A / D conversion circuit are connected in sequence;

[0006] The filter circuit is used to filter out clutter, eliminate differential mode interference between input signals and common mode interference between input and circuit ground;

[0007] The current acquisition circuit is connected in parallel between the input lines of the high voltage to be measured, collects and isolates the high voltage signal, and is used to convert the high voltage signal into a current signal;

[0008] The voltage conversion circuit is used to convert the current signal into a low voltage signal;

[0009] The A / D conversion circuit is used to convert the low voltage signal into a digital signal.

[0010] Furthermore, the filter circuit includes an X capacitor C1, a Y capacitor C2, a Y capacitor C3, a filter capacitor C4, and a filter capacitor C5. The X capacitor C1 is connected in parallel between the two input terminals, the Y capacitor C2 and the filter capacitor C4 are respectively connected in parallel between one input terminal and the ground terminal, and the Y capacitor C3 and the filter capacitor C5 are respectively connected in parallel between the other input terminal and the ground terminal.

[0011] Furthermore, the current acquisition circuit includes a Hall sensor.

[0012] Furthermore, the current acquisition circuit also includes a linear amplifier and an emitter follower, and the Hall sensor, linear amplifier and emitter follower are connected in sequence, the input end of the Hall sensor is connected to the output end of the filter circuit, and the output end of the emitter follower is connected to the input end of the voltage conversion circuit.

[0013] Furthermore, the voltage conversion circuit includes an operational amplifier U2A and a T-type feedback circuit, and the output end of the operational amplifier U2A is connected to the inverting input end of the operational amplifier U2A through the T-type feedback circuit.

[0014] Furthermore, the T-type feedback circuit includes resistors R3, R4 and R5, one end of the resistor R3 is connected to the inverting input terminal of the operational amplifier U2A, the other end of the resistor R3 is connected to the signal output terminal of the operational amplifier U2A through the series resistor R5, and the common end of the resistor R3 and the resistor R5 is connected to the ground through the resistor R4.

[0015] Furthermore, the A / D conversion circuit includes an RC filter circuit and an electric power collection chip U3, and the RC filter circuit and the electric power collection chip U3 are connected in sequence.

[0016] Furthermore, the RC filter circuit includes a resistor R6 and a capacitor C10. The resistor R6 is connected in series between the output end of the voltage conversion circuit and the input end of the power collection chip U3. The capacitor C10 is connected in parallel between the two input ends of the power collection chip U3.

[0017] The beneficial effects of the present invention are:

[0018] (1) The high-voltage AC voltage acquisition circuit of the present invention has high precision, good linearity, and fast response, which improves the safety of the power system and reduces interference caused by external high-voltage signals.

[0019] (2) The current acquisition module of the present invention uses a Hall sensor to isolate the high-voltage and low-voltage parts. The primary and secondary sides of the Hall sensor have good electrical isolation, which can avoid the high-voltage signal from being directly introduced into the power system, greatly improving the safety of the system and reducing the interference caused by external high-voltage signals. At the same time, the Hall voltage sensor has the characteristics of high precision, good linearity, and fast response, which can enable the high-voltage signal to maintain a high precision after isolation conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a schematic structural diagram of a high-voltage AC voltage acquisition circuit according to an embodiment of the present invention;

[0021] Figure 2 4 is a circuit schematic diagram of a high-voltage AC voltage acquisition circuit according to an embodiment of the present invention.

[0022] In the figure,

[0023] 1. Filter circuit; 2. Current acquisition circuit; 3. Voltage conversion circuit; 4. A / D conversion circuit. DETAILED DESCRIPTION

[0024] The high-voltage AC voltage acquisition circuit provided by the present invention is explained and illustrated in detail below with reference to the accompanying drawings.

[0025] This embodiment specifically discloses a high voltage AC voltage acquisition circuit, such as Figure 1 As shown, it includes a filter circuit 1, a current acquisition circuit 2, a voltage conversion circuit 3 and an A / D conversion circuit 4, which are connected in sequence.

[0026] The filter circuit 1 is used to filter out clutter, eliminate differential mode interference between input signals and common mode interference between input and circuit ground. Figure 2 As shown, the filter circuit includes X-capacitor C1, Y-capacitor C2, Y-capacitor C3, filter capacitor C4, and filter capacitor C5. X-capacitor C1 is connected in parallel between the two input terminals, Y-capacitor C2 and filter capacitor C4 are connected in parallel between one input terminal and the ground terminal, and Y-capacitor C3 and filter capacitor C5 are connected in parallel between the other input terminal and the ground terminal. After the high-voltage AC power enters the filter circuit through the input terminal, X-capacitor C1 eliminates differential-mode interference, while Y-capacitor C2, Y-capacitor C3, filter capacitor C4, and filter capacitor C5 remove common-mode interference, thus removing interference signals introduced from the original signal. The high-voltage signal then enters current acquisition circuit 2.

[0027] The current acquisition circuit 2 is connected in parallel between the input lines of the high voltage to be measured, and collects and isolates the high voltage signal, which is used to convert the high voltage signal into a current signal. The current acquisition circuit includes a Hall sensor, which achieves isolation between high and low voltage by isolating the primary and secondary sides, converting the high voltage signal into a low current signal, thereby preventing the high voltage signal from being directly introduced into the power system. In a preferred embodiment, the current acquisition circuit also includes a linear amplifier and an emitter follower. The Hall sensor, the linear amplifier, and the emitter follower are connected in sequence. The input end of the Hall sensor is connected to the output end of the filter circuit, and the output end of the emitter follower is connected to the input end of the voltage conversion circuit. The low current signal after isolation and conversion by the Hall sensor is amplified by the linear amplifier, and then passes through the emitter follower to reduce the impact of the front-end signal and increase the output capacity. The amplified current signal enters the voltage conversion circuit 3.

[0028] The voltage conversion circuit 3 is used to convert the current signal into a low voltage signal; in this embodiment, Figure 2 As shown, the voltage conversion circuit includes an operational amplifier U2A and a T-type feedback circuit. The output of operational amplifier U2A is connected to the inverting input of operational amplifier U2A via the T-type feedback circuit. The T-type feedback circuit includes resistors R3, R4, and R5. One end of resistor R3 is connected to the inverting input of operational amplifier U2A, and the other end of resistor R3 is connected to the signal output of operational amplifier U2A via a series resistor R5. The common end of resistors R3 and R5 is connected to ground via resistor R4. Resistors R3, R4, and R5 convert current into voltage. The voltage conversion circuit can amplify small signals while reducing zero drift and achieving a larger input impedance and amplification factor.

[0029] The A / D conversion circuit 4 is used to convert the low voltage signal into a digital signal. Figure 2 As shown, the A / D conversion circuit includes an RC filter circuit and a power collection chip U3, which are connected in sequence. The RC filter circuit comprises a resistor R6 and a capacitor C10. Resistor R6 is connected in series between the output of the voltage conversion circuit and the input of the power collection chip U3, while capacitor C10 is connected in parallel between the two inputs of the power collection chip U3. The power collection chip U3 uses an existing power collection chip with an integrated second-order ADC and a temperature sensor. The ADC utilizes the Σ-Δ principle. The RC filter circuit selects the signal frequency, and the second-order ADC within the power collection chip U3 converts the voltage into a digital signal. Finally, the temperature sensor integrated within the power collection chip U3 performs temperature compensation on the collected voltage signal to improve the circuit's measurement accuracy.

[0030] Specifically, an X capacitor C1 is connected in parallel between the first input terminal and the second input terminal of the circuit to eliminate differential-mode interference. A Y capacitor C2 is connected in parallel between the first input terminal and the ground terminal. A filter capacitor C4 is further connected in parallel between the first input terminal and the ground terminal. A Y capacitor C3 is connected in parallel between the second input terminal and the ground terminal. A filter capacitor C5 is further connected in parallel between the second input terminal and the ground terminal. The Y capacitor C2, the filter capacitor C4, the Y capacitor C3, and the filter capacitor C5 eliminate common-mode interference. Pins 1 and 2 of the current acquisition circuit U1 are connected to the positive output end of the filter circuit, pins 3 and 4 of the current acquisition circuit U1 are connected to the negative output end of the filter circuit, pin 8 of the current acquisition circuit U1 is connected to the power supply, pin 7 of the current acquisition circuit U1 is connected to one end of the resistor R2, pin 6 of the current acquisition circuit U1 is connected to the non-inverting input end of the operational amplifier U2A, pin 5 of the current acquisition circuit U1 is grounded, capacitor C7 is connected in parallel between pins 5 and 6, capacitor C8 is connected in parallel between pins 5 and 7, resistor R1 is connected in parallel between pins 6 and 8, the other end of resistor R2 is connected to the inverting input end of the operational amplifier U2A, one end of resistor R3 is connected to the inverting input end of the operational amplifier U2A, the other end of resistor R3 is connected to the signal output end of the operational amplifier U2A through a series resistor R5, and the common end of resistors R3 and R5 is connected to ground through resistor R4. One end of the resistor R6 is connected to the signal output end of the operational amplifier U1A, and the other end of the resistor R6 is connected to the first pin of the power acquisition chip U3. A capacitor C10 is connected in parallel between the first and second pins of the power acquisition chip U3.

[0031] The specific acquisition process of the high-voltage AC voltage acquisition circuit of this embodiment is as follows: the AC high voltage is input into the filter circuit, and the differential mode interference is eliminated by the X capacitor C1, and the common mode interference is removed by the Y capacitor C2, Y capacitor C3, filter capacitor C4, and filter capacitor C5, thereby removing the interference signal brought by the original signal; then it enters the current acquisition circuit, and the high voltage and low voltage are isolated by the primary coil and secondary coil of the Hall sensor, and the high voltage signal is converted into a low current signal, which is amplified by the linear amplifier and emitter follower; the amplified current signal passes through the T-type feedback circuit composed of the operational amplifier U2A and R3, R4, and R5, and the current signal is converted into a voltage signal. The voltage signal is processed by the RC filter circuit composed of R6 and C10, and then the power acquisition chip U3 uses analog acquisition and the internal integrated temperature sensor to compensate for the collected voltage, and then converts the voltage signal into a digital signal for external output.

[0032] The AC voltage acquisition circuit of the present invention realizes high voltage isolation, high precision and small error.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In the present invention, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] In the description of this specification, the reference terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in an appropriate manner in any at least one embodiment or example. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and simple improvements made to the essential contents of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high voltage AC voltage acquisition circuit, characterized in that: It includes a filter circuit, a current acquisition circuit, a voltage conversion circuit and an A / D conversion circuit, wherein the filter circuit, the current acquisition circuit, the voltage conversion circuit and the A / D conversion circuit are connected in sequence; The filter circuit is used to filter out clutter, eliminate differential-mode interference between input signals and common-mode interference between the input and the circuit ground. The filter circuit includes an X capacitor C1, a Y capacitor C2, a Y capacitor C3, a filter capacitor C4, and a filter capacitor C5. The X capacitor C1 is connected in parallel between the two input terminals, the Y capacitor C2 and the filter capacitor C4 are respectively connected in parallel between one input terminal and the ground terminal, and the Y capacitor C3 and the filter capacitor C5 are respectively connected in parallel between the other input terminal and the ground terminal. The current acquisition circuit is connected in parallel between the input lines of the high voltage to be measured, collects and isolates the high voltage signal, and is used to convert the high voltage signal into a current signal. The current acquisition circuit includes a Hall sensor, and the current acquisition circuit also includes a linear amplifier and an emitter follower. The Hall sensor, the linear amplifier and the emitter follower are connected in sequence. The input end of the Hall sensor is connected to the output end of the filter circuit, and the output end of the emitter follower is connected to the input end of the voltage conversion circuit. The voltage conversion circuit is used to convert the current signal into a low voltage signal; The A / D conversion circuit is used to convert the low voltage signal into a digital signal.

2. The high-voltage AC voltage acquisition circuit according to claim 1, characterized in that: The voltage conversion circuit includes an operational amplifier U2A and a T-type feedback circuit. The output end of the operational amplifier U2A is connected to the inverting input end of the operational amplifier U2A through the T-type feedback circuit.

3. The high-voltage AC voltage acquisition circuit according to claim 2, characterized in that: The T-type feedback circuit includes resistors R3, R4 and R5. One end of resistor R3 is connected to the inverting input terminal of the operational amplifier U2A, and the other end of resistor R3 is connected to the signal output terminal of the operational amplifier U2A through the series resistor R5. The common end of resistors R3 and R5 is connected to the ground through resistor R4.

4. The high-voltage AC voltage acquisition circuit according to claim 1, characterized in that: The A / D conversion circuit includes an RC filter circuit and an electric quantity collection chip U3 , and the RC filter circuit and the electric quantity collection chip U3 are connected in sequence.

5. The high-voltage AC voltage acquisition circuit according to claim 4, characterized in that: The RC filter circuit includes a resistor R6 and a capacitor C10. The resistor R6 is connected in series between the output end of the voltage conversion circuit and the input end of the power collection chip U3. The capacitor C10 is connected in parallel between the two input ends of the power collection chip U3.

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