Operational amplifier sampling circuit and circuit breaker

Abstract

The utility model discloses an operational amplifier sampling circuit and a circuit breaker, the operational amplifier sampling circuit comprises operational amplifier sampling modules respectively and correspondingly connected with the output end of each phase of three-phase power, and each operational amplifier sampling module comprises an input load unit and an operational amplifier unit. The first end of the input load unit is connected to the inverted input end of the operational amplification unit, the second end of the input load unit is connected to the in-phase input end of the operational amplification unit, and the output end of the operational amplification unit is connected with a main control module used for receiving sampling voltage signals. And the main control module carries out voltage protection and frequency protection based on the sampling voltage signal. The input load unit is bridged between the in-phase input end and the inverted input end of the operational amplification unit of each operational amplification sampling module to increase the load of the input end, so that the offset of a voltage neutral point can be reduced, the sampling precision is improved, and the reliability of the circuit breaker is improved.

Description

Technical Field

[0001] The present application relates to the technical field of circuit breakers, and in particular to an operational amplifier sampling circuit and a circuit breaker. Background Art

[0002] A dual power conversion control circuit breaker, also known as a dual power conversion switch, is a switching device that can automatically switch to the backup power supply to ensure continuous operation of the equipment when the normal power supply fails (such as overvoltage, undervoltage, phase loss, frequency deviation, etc.) or a power outage occurs.

[0003] At present, most of the dual power conversion control circuit breakers adopt the operational amplifier sampling method to perform voltage and frequency sampling. However, in practical applications, the sampling accuracy of the sampled voltage is often reduced due to the offset of the voltage neutral point, which affects the operation of the circuit breaker. Utility Model Content

[0004] In view of the above problems, the present application provides an operational amplifier sampling circuit and a circuit breaker to solve the above technical problems.

[0005] In the first aspect, the present application provides an operational amplifier sampling circuit, which includes an operational amplifier sampling module respectively connected to each phase output end of the three-phase electricity, each operational amplifier sampling module includes an input load unit and an operational amplifier unit, the first end of the input load unit is connected to the inverting input end of the operational amplifier unit, the second end of the input load unit is connected to the non-inverting input end of the operational amplifier unit, and the output end of the operational amplifier unit is connected to a main control module for receiving a sampled voltage signal, so that the main control module performs voltage protection and frequency protection based on the sampled voltage signal.

[0006] In a possible implementation of the present application, the input load unit includes a first resistance circuit, and the first resistance circuit includes at least one resistor connected in series.

[0007] In a possible implementation of the present application, the operational amplifier sampling module further includes an inverting resistor circuit connected to the inverting input terminal of the operational amplifier unit, and the inverting resistor circuit includes at least one resistor connected in series.

[0008] In a possible implementation of the present application, the operational amplifier sampling module further includes a non-inverting resistor circuit connected to the non-inverting input terminal of the operational amplifier unit, and the non-inverting resistor circuit is symmetrical to the anti-inverting resistor circuit.

[0009] In a possible implementation of the present application, the in-phase resistance circuit includes at least one resistor connected in series.

[0010] In a possible implementation of the present application, the operational amplifier sampling module also includes a first integral filter unit connected between the inverting input terminal and the output terminal of the operational amplifier unit, and the first integral filter unit includes an inverting terminal resistor and an inverting terminal capacitor connected in parallel.

[0011] In a possible implementation of the present application, the operational amplifier sampling module also includes a second integral filter unit connected to the reference voltage output terminal and the non-inverting input terminal of the operational amplifier unit, the second integral filter unit includes a non-inverting terminal resistor and a non-inverting terminal capacitor connected in parallel, and the non-inverting terminal resistor is symmetrical with the inverting terminal resistor, and the non-inverting terminal capacitor is symmetrical with the inverting terminal capacitor.

[0012] In a possible implementation of the present application, the operational amplifier sampling module further includes an energy storage filter unit connected to the power input terminal of the operational amplifier unit, and the energy storage filter unit includes an energy storage capacitor and a filter capacitor.

[0013] In a possible implementation of the present application, the operational amplifier sampling circuit further includes a reference voltage module, and the reference voltage module is respectively connected to the non-inverting input terminal of each operational amplifier unit to output a reference voltage signal.

[0014] In a second aspect, the present application further provides a circuit breaker, which includes a circuit breaker body and the operational amplifier sampling circuit of the first aspect, the circuit breaker body includes a main control module, and the operational amplifier sampling circuit is connected to the main control module.

[0015] From the above content, it can be concluded that the present application has the following beneficial effects:

[0016] The operational amplifier sampling circuit provided in the present application includes operational amplifier sampling modules corresponding to each phase of the three-phase electricity. By bridging an input load unit between the in-phase input terminal and the inverting input terminal of the operational amplifier unit of each operational amplifier sampling module to increase the load on the input terminal, the offset of the voltage neutral point can be reduced, the sampling accuracy can be improved, and thus the reliability of the circuit breaker can be improved.

[0017] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a module schematic diagram of an operational amplifier sampling circuit provided in an embodiment of the present application;

[0020] Figure 2 is a structural schematic diagram of an operational amplifier sampling circuit provided in an embodiment of the present application;

[0021] Figure 3is a time domain waveform diagram of the collected data provided in the embodiment of the present application;

[0022] Figure 4 is a structural schematic diagram of an input load unit provided in an embodiment of the present application;

[0023] Figure 5 is a structural diagram of an operational amplifier sampling module provided in an embodiment of the present application;

[0024] Figure 6 It is a circuit principle diagram of the operational amplifier sampling module provided in the embodiment of the present application;

[0025] Figure 7 is another module schematic diagram of the operational amplifier sampling circuit provided in an embodiment of the present application;

[0026] Figure 8 It is a circuit principle diagram of a voltage follower circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0028] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0029] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0030] Moreover, the terms "comprises", "comprising" or any other variation thereof are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of more restrictions, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or device comprising the element.

[0031] In the description of the embodiments of the present application, words such as "example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "example" or "for example" in the embodiments of the present application is not to be interpreted as being more preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to present relative concepts in a clear manner.

[0032] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0033] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0034] The operational amplifier sampling circuit and circuit breaker provided in the present application are described in detail below.

[0035] First, the present application embodiment provides an operational amplifier sampling circuit, see Figure 1 , Figure 1 It is a module schematic diagram of the operational amplifier sampling circuit provided in an embodiment of the present application. The operational amplifier sampling circuit 10 may include an operational amplifier sampling module 100 respectively connected to each phase output terminal XI of the three-phase electricity. Each operational amplifier sampling module 100 may include an input load unit 110 and an operational amplifier unit 120. The first end of the input load unit 110 may be connected to the inverting input terminal of the operational amplifier unit 120, and the second end of the input load unit 110 may be connected to the non-inverting input terminal of the operational amplifier unit 120. The output terminal of the operational amplifier unit 120 may be connected to a main control module 20 for receiving a sampled voltage signal, so that the main control module 20 can perform voltage protection and frequency protection based on the received sampled voltage signal.

[0036] In the embodiment of the present application, the output terminal XI can be any one of the A-phase terminal AI, the B-phase terminal BI and the C-phase terminal CI in the ABC three-phase electricity, and the NI terminal connected to the same-phase input terminal is the neutral line terminal.

[0037] Specifically, Figure 2As shown, the operational amplifier sampling circuit 10 may include an A-phase operational amplifier sampling module 100a, a B-phase operational amplifier sampling module 100b and a C-phase operational amplifier sampling module 100c, wherein the A-phase operational amplifier sampling module 100a may include an A-phase input load unit 110a and an A-phase operational amplifier unit 120a correspondingly connected to the A-phase terminal AI and the neutral line terminal NI; the B-phase operational amplifier sampling module 100b may include a B-phase input load unit 110b and a B-phase operational amplifier unit 120b correspondingly connected to the B-phase terminal BI and the neutral line terminal NI; and the C-phase operational amplifier sampling module 100c may include a C-phase input load unit 110c and a C-phase operational amplifier unit 120c correspondingly connected to the C-phase terminal CI and the neutral line terminal NI.

[0038] Among them, the A-phase input load unit 110a is connected between the non-inverting input terminal and the inverting input terminal of the A-phase operational amplifier unit 120a, the B-phase input load unit 110b is connected between the non-inverting input terminal and the inverting input terminal of the B-phase operational amplifier unit 120b, and the C-phase input load unit 110c is connected between the non-inverting input terminal and the inverting input terminal of the C-phase operational amplifier unit 120c. The output terminals of the A-phase operational amplifier unit 120a, the B-phase operational amplifier unit 120b and the C-phase operational amplifier unit 120c are all connected to the main control module 20.

[0039] In the embodiment of the present application, the voltage of the ABC three-phase electricity can be sampled respectively by the A-phase operational amplifier sampling module 100a, the B-phase operational amplifier sampling module 100b and the C-phase operational amplifier sampling module 100c, so that the A-phase operational amplifier sampling module 100a, the B-phase operational amplifier sampling module 100b and the C-phase operational amplifier sampling module 100c can transmit the sampled voltage signals obtained by their respective sampling to the main control module 20, so that the main control module 20 can perform overvoltage, undervoltage and loss of voltage protection according to the received sampled voltage signals. At the same time, the main control module 20 can also perform further frequency sampling on the sampled voltage signal, thereby realizing frequency protection such as overfrequency and underfrequency.

[0040] For example, the main control module 20 can collect data of the sampled voltage signal according to a preset sampling frequency fs such as 3200Hz, store the collected data in a buffer array in groups of 64 points, and then take out the maximum and minimum values ​​in each array and record the subscript Nx corresponding to the maximum and minimum values ​​respectively, and convert the discrete time into continuous time. The conversion formula is t=Nx*(1 / fs), so as to obtain the time of the maximum value and the time of the minimum value in each array, and the difference between the time of the minimum value and the time of the maximum value can obtain the duration of half a cycle. After continuously calculating the half cycles corresponding to multiple groups of data, the average is taken to obtain the frequency, realize frequency sampling, and then perform over-frequency and under-frequency protection according to the obtained frequency.

[0041] like Figure 3As shown, in the embodiment of the present application, three groups of data are taken, among which the time of the maximum value in the first group is t1, the time of the minimum value is t2, and the duration of half a cycle is T1=t2-t1; the time of the maximum value in the second group is t3, the time of the minimum value is t4, and the duration of half a cycle is T2=t4-t3; the time of the maximum value in the third group is t5, the time of the minimum value is t6, and the duration of half a cycle is T3=t6-t5; after taking the average, the period T=2*(T1+T2+T3) / 3 is obtained, and finally the frequency f=1 / T is obtained.

[0042] In the present application, the operational amplifier sampling circuit 10 includes an operational amplifier sampling module 100 corresponding to each phase of the three-phase electricity. By connecting an input load unit 110 across the in-phase input terminal and the inverting input terminal of the operational amplifier unit 120 of each operational amplifier sampling module 100 to increase the load on the input terminal, the offset of the voltage neutral point can be reduced, the sampling accuracy can be improved, and thus the reliability of the circuit breaker can be improved.

[0043] Since the A-phase operational amplifier sampling module 100a, the B-phase operational amplifier sampling module 100b and the C-phase operational amplifier sampling module 100c have the same structure, Figure 1 For example, continue with Figure 1 Each unit module shown and the specific implementation methods that may be used in practical applications are explained in detail.

[0044] In some embodiments of the present application, the input load unit 110 may include a first resistance circuit 1101, and the first resistance circuit 1101 may include at least one resistor connected in series. Figure 4 As shown, in the embodiment of the present application, the first resistor circuit 1101 includes a first resistor R1 connected between the inverting input terminal and the non-inverting input terminal of the operational amplifier unit 120 .

[0045] It can be understood that in some other embodiments, the first resistance circuit 1101 can also include 2, 3 or more resistors connected in series between the inverting input terminal and the non-inverting input terminal of the operational amplifier unit 120. The number of series resistors can be determined according to the actual application scenario and is not limited here.

[0046] In some embodiments of the present application, the operational amplifier sampling module 100 may further include an inverting resistor circuit 130 connected to the inverting input terminal of the operational amplifier unit 120 , and the inverting resistor circuit 130 may include at least one resistor connected in series.

[0047] like Figure 5As shown, the inverting resistor circuit 130 includes a second resistor R2 connected between the first end of the input load unit 110 and the inverting input end of the operational amplifier unit 120. It can be understood that in some other embodiments, the inverting resistor circuit 130 can also include 2, 3 or more resistors connected in series between the first end of the input load unit 110 and the inverting input end of the operational amplifier unit 120. The number of series resistors can be determined according to the actual application scenario and is not limited here.

[0048] In the embodiment of the present application, the inverting resistor circuit 130 adopts a resistor voltage division method, which can withstand surge impact and increase the service life of the electronic components.

[0049] Please continue reading Figure 5 In some embodiments of the present application, the operational amplifier sampling module 100 may further include a non-inverting resistor circuit 140 connected to the non-inverting input terminal of the operational amplifier unit 120 , and the non-inverting resistor circuit 140 is symmetrical to the inverting resistor circuit 130 .

[0050] In an embodiment of the present application, the common-phase resistance circuit 140 can be connected between the second end of the input load unit 110 and the common-phase input end of the operational amplifier unit 120. The common-phase resistance circuit 140 is symmetrical with the anti-phase resistance circuit 130, that is, the total resistance of the common-phase resistance circuit 140 and the anti-phase resistance circuit 130 is equal.

[0051] like Figure 5 As shown, the in-phase resistance circuit 140 includes a third resistor R3 connected between the second end of the input load unit 110 and the in-phase input end of the operational amplifier unit 120, and the third resistor R3 is symmetrical with the second resistor R2, that is, the third resistor R3 is the same as the second resistor R2.

[0052] In the embodiment of the present application, a resistor circuit symmetrical to the inverting input terminal is added to the non-inverting input terminal of the operational amplifier unit 120 for decoupling, which can reduce the coupling interference between the inverting input terminal and the non-inverting input terminal and improve the accuracy of the sampled voltage signal.

[0053] like Figure 6 As shown, in some embodiments of the present application, the operational amplifier unit 120 includes an operational amplifier U7A, and the first resistance circuit 1101 includes a resistor string connected across the inverting input terminal and the non-inverting input terminal of the operational amplifier U7A, and the resistor string includes a seventy-first resistor R71 and a seventy-fifth resistor R75 connected in series, and the seventy-first resistor R71 and the seventy-fifth resistor R75 are both 200KΩ 1206 package resistors.

[0054] The inverting resistor circuit 130 includes a sixty-seventh resistor R67, a sixty-eighth resistor R68, a sixty-ninth resistor R69 and a seventy-first resistor R70 connected in series, and the in-phase resistor circuit 140 includes a seventy-sixth resistor R76, a seventy-second resistor R72, a seventy-third resistor R73 and a seventy-fourth resistor R74 connected in series.

[0055] The operational amplifier sampling module 100 may further include a first integral filter unit 150 connected between the inverting input terminal and the output terminal of the operational amplifier U7A, and the first integral filter unit 150 may include an inverting terminal resistor R48 and an inverting terminal capacitor C30 connected in parallel. The inverting terminal resistor R48 may control the amplification factor of the signal, and the inverting terminal capacitor C30 may filter out signal interference to stabilize the output sampling voltage signal.

[0056] Please continue reading Figure 6 In some embodiments of the present application, the operational amplifier sampling module 100 may further include a second integral filter unit 160 connected to the reference voltage output terminal Vref and the non-inverting input terminal of the operational amplifier U7A. The second integral filter unit 160 may include a non-inverting terminal resistor R77 and a non-inverting terminal capacitor C35 connected in parallel, and the non-inverting terminal resistor R77 is symmetrical with the inverting terminal resistor R48, and the non-inverting terminal capacitor C35 is symmetrical with the inverting terminal capacitor C30.

[0057] In the embodiment of the present application, by setting a common-phase terminal resistor R77 symmetrical to the inverting terminal resistor R48 and a common-phase terminal capacitor C35 symmetrical to the inverting terminal capacitor C30 at the common-phase input terminal of the operational amplifier U7A, the output sampling voltage signal can be made more stable, further improving the reliability of the circuit.

[0058] In some embodiments of the present application, the operational amplifier sampling module 100 may further include an energy storage filter unit 170 connected to the power input terminal of the operational amplifier U7A, namely, pin 4. The energy storage filter unit 170 may include an energy storage capacitor C31 and a filter capacitor C32.

[0059] In the embodiment of the present application, the power input terminal of the operational amplifier U7A is connected to the 3.3V power supply terminal and the energy storage capacitor C31, so that the energy storage capacitor C31 can use the 3.3V voltage output by the 3.3V power supply terminal to store energy; the filter capacitor C32 and the energy storage capacitor C31 are connected in parallel between the power input terminal and the ground terminal GND of the operational amplifier U7A, which can filter out the interference signal on the 3.3V voltage output by the 3.3V power supply terminal to ensure stable power supply.

[0060] like Figure 7As shown, in some embodiments of the present application, the operational amplifier sampling circuit 10 may further include a reference voltage module 200. The reference voltage module 200 may be respectively connected to the non-inverting input terminal of each operational amplifier unit 120 to output a reference voltage signal Vref.

[0061] In the embodiment of the present application, each operational amplifier unit 120 is respectively connected to the reference voltage module 200 to access the reference voltage signal Vref provided by the reference voltage module 200. That is to say, the reference voltage signal Vref of each operational amplifier unit 120 is relatively independent, which can reduce signal interference between phases and further improve the accuracy of the sampled voltage signal.

[0062] The reference voltage signal Vref is a reference voltage after the voltage follows, and specifically, the amplitude of the reference voltage signal Vref may be half of the supply voltage, for example, half of the 3.3 V voltage, i.e., 1.65 V. It is understandable that when the supply voltage changes, the reference voltage signal Vref provided by the reference voltage module 200 may also change accordingly, which is not specifically limited here.

[0063] In the embodiment of the present application, the reference voltage module 200 can adopt any existing reference voltage generating circuit, such as Figure 8 The voltage follower circuit shown is not an improved part of the present application and thus will not be described in detail here.

[0064] Based on the above embodiments, the present application also provides a circuit breaker, which may include a circuit breaker body and a Figures 1 to 7 Corresponding to the operational amplifier sampling circuit 10 in any embodiment, the circuit breaker body may include a main control module 20 , and the operational amplifier sampling circuit 10 is connected to the main control module 20 .

[0065] In the embodiment of the present application, the circuit breaker may be a miniature circuit breaker, a dual power conversion control circuit breaker, etc.

[0066] Since the circuit breaker includes the present application Figures 1 to 7 Corresponding to the operational amplifier sampling circuit 10 in any embodiment, therefore, the present application can be implemented as follows Figures 1 to 7 For all the beneficial effects that can be achieved by the operational amplifier sampling circuit 10 in any embodiment, please refer to the previous description in detail, which will not be repeated here.

[0067] The above are only preferred embodiments of the present application, and are not intended to limit the present application in any form. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. An operational amplifier sampling circuit, characterized in that: It includes operational amplifier sampling modules respectively connected to each phase output end of the three-phase electricity, each of the operational amplifier sampling modules includes an input load unit and an operational amplifier unit, the first end of the input load unit is connected to the inverting input end of the operational amplifier unit, the second end of the input load unit is connected to the non-inverting input end of the operational amplifier unit, and the output end of the operational amplifier unit is connected to a main control module for receiving a sampled voltage signal, so that the main control module performs voltage protection and frequency protection based on the sampled voltage signal.

2. The operational amplifier sampling circuit according to claim 1, characterized in that: The input load unit includes a first resistance circuit including at least one resistor connected in series.

3. The operational amplifier sampling circuit according to claim 1, characterized in that: The operational amplifier sampling module further includes an inverting resistor circuit connected to the inverting input terminal of the operational amplifier unit, and the inverting resistor circuit includes at least one resistor connected in series.

4. The operational amplifier sampling circuit according to claim 3, characterized in that: The operational amplifier sampling module further includes a common-phase resistor circuit connected to the common-phase input terminal of the operational amplifier unit, and the common-phase resistor circuit is symmetrical with the inverting resistor circuit.

5. The operational amplifier sampling circuit according to claim 4, characterized in that: The in-phase resistance circuit includes at least one resistor connected in series.

6. The operational amplifier sampling circuit according to claim 1, characterized in that: The operational amplifier sampling module further includes a first integral filter unit connected between the inverting input terminal and the output terminal of the operational amplifier unit, and the first integral filter unit includes an inverting terminal resistor and an inverting terminal capacitor connected in parallel.

7. The operational amplifier sampling circuit according to claim 6, characterized in that: The operational amplifier sampling module also includes a second integral filtering unit connected to the reference voltage output terminal and the non-inverting input terminal of the operational amplifier unit, the second integral filtering unit includes a non-inverting terminal resistor and a non-inverting terminal capacitor connected in parallel, and the non-inverting terminal resistor is symmetrical with the inverting terminal resistor, and the non-inverting terminal capacitor is symmetrical with the inverting terminal capacitor.

8. The operational amplifier sampling circuit according to claim 1, characterized in that: The operational amplifier sampling module further includes an energy storage filter unit connected to the power input terminal of the operational amplifier unit, and the energy storage filter unit includes an energy storage capacitor and a filter capacitor.

9. The operational amplifier sampling circuit according to any one of claims 1 to 8, characterized in that: The operational amplifier sampling circuit further comprises a reference voltage module, and the reference voltage module is respectively connected to the non-inverting input terminal of each operational amplifier unit to output a reference voltage signal.

10. A circuit breaker, characterized in that: It comprises a circuit breaker body and an operational amplifier sampling circuit as claimed in any one of claims 1 to 9, wherein the circuit breaker body comprises a main control module, and the operational amplifier sampling circuit is connected to the main control module.

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