Three-phase overcurrent detection circuit

Abstract

The embodiment of the invention discloses a three-phase overcurrent detection circuit. According to the circuit, three-phase input voltage signals are collected through the three-phase current input module and the bias voltage module, real-time voltage in the voltage signals is compared with threshold voltage based on the comparison module, when any phase in the three-phase real-time voltage exceeds the threshold voltage, it is represented that an overcurrent phenomenon occurs, and the overcurrent phenomenon is detected. A trigger signal is continuously sent through the trigger module, finally, a fault signal is sent through the fault output module, through the detection circuit which is all constructed by hardware, the purposes of rapidly responding to an over-current fault and timely protecting a post-stage circuit are achieved, the self-locking and resetting functions are achieved, and it is guaranteed that an over-current signal cannot be interfered by other signals.

Description

Technical Field

[0001] One or more embodiments of the present specification relate to the field of overcurrent detection technology, and in particular, to a three-phase overcurrent detection circuit. Background Art

[0002] In water power products, unexpected situations can cause three-phase overcurrent inputs to the equipment. Failure to promptly address these issues can lead to equipment damage and economic losses. Therefore, real-time overcurrent signal detection of the three-phase input is necessary. Currently, single-chip microcontroller (MCU) detection methods are commonly used. However, as the shutdown hub, these methods require program logic judgment, resulting in a slow response. This can delay protection for some high-power devices, potentially leading to device burnout, and prevents self-locking and resetting of overcurrent signals. Summary of the Invention

[0003] To solve the problems existing in the prior art, one or more embodiments of this specification describe a three-phase overcurrent detection circuit.

[0004] A three-phase overcurrent detection circuit is provided in the present application, which includes a three-phase current input module, a bias voltage module, a comparison module, a trigger module and a fault output module. The three-phase current input module is electrically connected to the bias voltage module, the bias voltage module is electrically connected to the comparison module, the comparison module is electrically connected to the trigger module, and the trigger module is electrically connected to the fault output module.

[0005] Preferably, the three-phase current input module includes a filter resistor and a diode, the first end of the filter resistor is electrically connected to the single-phase current of the three-phase current to be measured, the second end of the filter resistor is electrically connected to the first end of the diode, and the second end of the diode is electrically connected to the bias voltage module.

[0006] Preferably, the bias voltage module includes a first bias voltage module and a second bias voltage module, the first end of the first bias voltage module is electrically connected to the second end of the diode, the second end of the first bias voltage module is grounded, the first end of the second bias voltage module is electrically connected to the comparison module, and the second end of the second bias voltage module is grounded.

[0007] Preferably, the first bias voltage module includes a first voltage divider resistor module and a first voltage follower, the input end of the first voltage follower is electrically connected to the first voltage divider resistor module, and the output end of the first voltage follower is electrically connected to the first input end of the comparison module.

[0008] Preferably, the second bias voltage module includes a second voltage-dividing resistor module and a second voltage follower, the input end of the second voltage follower is electrically connected to the second voltage-dividing resistor module, and the output end of the second voltage follower is electrically connected to the second input end of the comparison module.

[0009] Preferably, the comparison module includes a first filter capacitor and a comparator, the first end of the first filter capacitor is electrically connected to the input end of the comparator, the second end of the first filter capacitor is grounded, and the output end of the comparator is electrically connected to the trigger module.

[0010] Preferably, the trigger module includes a second filter capacitor and a D-type trigger, the first input end of the D-type trigger is electrically connected to the comparison module, the output end of the D-type trigger is electrically connected to the fault output module, the first end of the second filter capacitor is electrically connected to the second input end of the D-type trigger, and the second end of the second filter capacitor is grounded.

[0011] Preferably, the trigger module further includes a reset button, a first end of the reset button is electrically connected to the third input end of the D-type trigger, and a second end of the reset button is grounded.

[0012] Preferably, the fault output module includes a MOS tube and a gate resistor, a first end of the gate resistor is electrically connected to the trigger module, a second end of the gate resistor is connected to the gate of the MOS tube, and the source of the MOS tube is grounded.

[0013] Preferably, the circuit also includes a first pull-up resistor, a second pull-up resistor and a third pull-up resistor, the first end of the first pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the first pull-up resistor is electrically connected to the output end of the comparison module, the first end of the second pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the second pull-up resistor is electrically connected to the input end of the trigger module, the first end of the third pull-up resistor is electrically connected to the positive pole of the power supply, and the second end of the third pull-up resistor is electrically connected to the output end of the fault output module.

[0014] The beneficial effects of the present invention are: The three-phase overcurrent detection circuit provided in the embodiment of this specification collects the voltage signal of the three-phase input through the three-phase current input module and the bias voltage module, and then compares the real-time voltage in the voltage signal with the threshold voltage based on the comparison module. When any phase of the three-phase real-time voltage exceeds the threshold voltage, it indicates that an overcurrent phenomenon has occurred, and the trigger signal is continuously sent through the trigger module. Finally, a fault signal is sent through the fault output module. Through the above detection circuit constructed entirely by hardware, the purpose of responding quickly to overcurrent faults and protecting the subsequent circuits in time is achieved, and it has self-locking and reset functions to ensure that the overcurrent signal cannot be interfered with by other signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a schematic diagram of the architecture of a three-phase overcurrent detection circuit in the specific implementation of this specification; Figure 2 This is a schematic diagram of a three-phase overcurrent detection circuit in the specific implementation of this specification; Figure 3 This is a detection flow diagram of a three-phase overcurrent detection circuit in the specific implementation of this specification. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0018] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present application. Different embodiments can be replaced or combined, so the present application can also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, even though the embodiment may not be clearly described in the following text.

[0019] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present application. Various examples may appropriately omit, replace, or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described in some examples may be combined in other examples.

[0020] See also Figure 1 and Figure 2 , Figure 1 FIG1 shows a schematic diagram of the architecture of a three-phase overcurrent detection circuit provided in an embodiment of this specification. Figure 2 A schematic diagram of an implementation of a three-phase overcurrent detection circuit provided in an embodiment of this specification is shown.

[0021] like Figure 1 、 Figure 2 As shown, the three-phase overcurrent detection circuit includes a three-phase current input module, a bias voltage module, a comparison module, a trigger module, and a fault output module. The three-phase current input module is electrically connected to the bias voltage module, which is in turn electrically connected to the comparison module, which is then electrically connected to the trigger module, which is then electrically connected to the fault output module. The three-phase current input module acquires the real-time input current signal of the three-phase circuit under test and sends it to the bias voltage module. The bias voltage module converts the received current signal into a real-time voltage signal and simultaneously generates a voltage threshold signal, which is then sent to the comparison module. The comparison module makes a judgment based on the received real-time voltage signal and the voltage threshold signal. When the comparison module generates a detection result, it indicates that the real-time received voltage is greater than the voltage threshold, indicating that a three-phase current overcurrent has occurred. The comparison module then sends the detection result to the trigger module. Upon receiving the detection result, the trigger module issues a trigger signal, stores the detection data, and continuously sends trigger signals to the fault output module. Upon receiving the trigger signal, the fault output module outputs a fault signal to indicate that an overcurrent has occurred. Among them, when the real-time received voltage is not greater than the threshold voltage, the comparison module does not generate a detection result, and the subsequent corresponding trigger module and fault output module do not operate. This application compares the converted three-phase real-time voltage with the threshold voltage through the comparison module. When any phase of the three-phase real-time voltage exceeds the threshold voltage, it indicates that an overcurrent phenomenon has occurred, and the trigger module continuously sends a trigger signal. Finally, a fault signal is sent through the fault output module. Through the above detection circuit constructed entirely by hardware, the purpose of rapid response to faults and timely protection of the subsequent circuit is achieved, and it has a self-locking function to ensure that the overcurrent signal cannot be interfered with by other signals.

[0022] In one embodiment, the three-phase current input module may include three filter resistors R4, R5, and R6, and three diodes D1, D2, and D3, because the three-phase current input module corresponds to the input three-phase currents I_U, I_V, and I_W. The first end of the filter resistor R4 is electrically connected to the single-phase current I_U of the three-phase current to be measured, the second end of the filter resistor R4 is electrically connected to the first end of the diode D1, and the second end of the diode D1 is electrically connected to the output end of the bias voltage module. Similarly, the first end of the filter resistor R5 is electrically connected to the single-phase current I_V of the three-phase current to be measured, the second end of the filter resistor R5 is electrically connected to the first end of the diode D2, and the second end of the diode D2 is electrically connected to the output end of the bias voltage module. The first end of the filter resistor R6 is electrically connected to the single-phase current I_W of the three-phase current to be measured, the second end of the filter resistor R6 is electrically connected to the first end of the diode D3, and the second end of the diode D3 is electrically connected to the output end of the bias voltage module. Diodes D1, D2, and D3 are used to prevent three-phase voltage short circuits, avoid circuit damage, isolate abnormal reverse currents, improve system reliability, and protect front-end circuits. Filter resistors R4, R5, and R6 are used to suppress noise, reduce interference between phase current signals, improve circuit stability, and optimize signal detection accuracy.

[0023] In one embodiment, the bias voltage module includes a first bias voltage module and a second bias voltage module, wherein the first end of the first bias voltage module is electrically connected to the second end of the diodes D1, D2 and D3, the second end of the first bias voltage module is grounded, the first end of the second bias voltage module is electrically connected to the comparison module, and the second end of the second bias voltage module is grounded. Since the collected three-phase current is an AC signal, it contains positive and negative half-cycle current signals, and the subsequent comparison module usually requires a unipolar input, that is, a positive voltage input signal. If the AC signal is directly input to the comparator, the negative half-cycle voltage may be lower than the common mode input range of the comparator, resulting in the signal being unable to be correctly detected. Therefore, by superimposing the first bias voltage module after the three-phase current input module, the AC signal is raised to the positive voltage range as a whole. As an example, the original AC signal range is -1V to +1V, and after superimposing 2.5V, it becomes 1.5V to 3.5V, ensuring that the comparison module can process normally. Furthermore, in order to provide a threshold voltage for comparison in a subsequent comparison module and a corresponding bias voltage when overcurrent occurs, a second bias voltage module may be provided to provide a stable voltage threshold for subsequent determination of whether an overcurrent phenomenon occurs.

[0024] In one embodiment, the first bias voltage module may include a first voltage-dividing resistor module, the first voltage-dividing resistor module including a voltage-dividing resistor R1 and a voltage-dividing resistor R2, and a first voltage follower U1A, the input end of the first voltage follower U1A being electrically connected to the first voltage-dividing resistor module, and the output end of the first voltage follower U1A being electrically connected to the first input end of the comparison module. The voltage-dividing resistors R1 and R2 in the first voltage-dividing resistor module are connected in series, the input end of the first voltage follower U1A being electrically connected to the midpoint of the circuit between the voltage-dividing resistors R1 and R2, the midpoint voltage being determined by the voltage-dividing resistors R1 and R2, and when R1=R2, the output is half the power supply voltage. The output voltage of the first bias voltage module is controlled by regulating the size of the voltage-dividing resistors R1 and R2.

[0025] In one embodiment, the second bias voltage module includes a second voltage-dividing resistor module, which includes voltage-dividing resistors R7 and R8, and a second voltage follower U2A. The input end of the second voltage follower U2A is electrically connected to the second voltage-dividing resistor module, and the output end of the second voltage follower U2A is electrically connected to the second input end of the comparison module. The voltage-dividing resistors R7 and R8 in the second voltage-dividing resistor module are connected in series, and the input end of the second voltage follower U2A is electrically connected to the circuit midpoint of the voltage-dividing resistors R7 and R8. The midpoint voltage is determined by the voltage-dividing resistors R7 and R8. By adjusting the values ​​of the voltage-dividing resistors R7 and R8, the threshold voltage output by the second bias voltage module is controlled.

[0026] In one embodiment, the comparison module may include a comparator U3. Since the comparator U3 includes two input terminals, the comparison module also includes two first filter capacitors, namely, filter capacitor C1 and filter capacitor C2. The first end of the filter capacitor C1 is electrically connected to the first input terminal of the comparator U3, the second end of the filter capacitor C2 is grounded, the first end of the filter capacitor C1 is electrically connected to the first input terminal of the comparator U3, the second end of the filter capacitor C2 is grounded, and the output terminal of the comparator U3 is electrically connected to the trigger module. At the same time, the inverting terminal of the comparator U3, namely the first input terminal, is connected to the output terminal of the first voltage follower U1A, and the non-inverting terminal of the comparator U3, namely the second input terminal, is connected to the output terminal of the second voltage follower U1A. When the voltage at the inverting terminal is higher than the voltage at the non-inverting terminal, the comparator U3 outputs a high level, otherwise it outputs a low level. The filter capacitor C1 and filter capacitor C2 are provided together with the filter resistors R4, R5 and R6 in the three-phase current input module to filter out high-frequency noise, smooth the signal waveform, and improve the stability of the circuit.

[0027] In one embodiment, the trigger module includes a second filter capacitor C4 and a D-type trigger U4. The first input terminal of the D-type trigger U4 is electrically connected to the output terminal of the comparator U3 in the comparison module, the output terminal of the D-type trigger U4 is electrically connected to the fault output module, the first terminal of the second filter capacitor C4 is electrically connected to the second input terminal of the D-type trigger U4, and the second terminal of the second filter capacitor C4 is grounded. When the first input terminal of the D-type trigger U4 inputs a high level, when its corresponding CLK pin detects a rising edge, the output logic corresponding to the D pin is transmitted to the output terminal of the D-type trigger U4, and the logic data is stored. The trigger signal is continuously sent to the fault output module by being electrically connected to the fault output module. The second filter capacitor C4 is provided to filter out interference signals from the CLK pin to prevent false triggering of signals.

[0028] In one embodiment, the trigger module further includes a reset button K1. A first end of the reset button K1 is electrically connected to the third input terminal of the D-type flip-flop U4, namely the reset pin REST, and a second end of the reset button K1 is grounded. A filter capacitor C3 may also be provided in the trigger module to filter out interference signals from the reset pin REST. Upon detecting an overcurrent signal, a trigger signal is continuously transmitted to the fault output module via the output terminal of the D-type flip-flop U4. To resolve the overcurrent fault, simply closing the reset button K1 resets the trigger signal sent from the output terminal of the D-type flip-flop U4 and maintains the monitoring state.

[0029] In one embodiment, the fault output module may include a MOS transistor Q1 and a gate resistor R11. The first end of the gate resistor R11 is electrically connected to the output end of a D-type trigger U4 in the trigger module, and the second end of the gate resistor R11 is connected to the gate of the MOS transistor Q1. The source of the MOS transistor Q1 is grounded. Upon receiving a trigger signal from the D-type trigger U4, the MOS transistor Q1 converts the trigger signal from the D-type trigger U4 into a control level and issues a fault signal, indicating an overcurrent condition. The gate resistor R11 is used to limit the gate current and suppress ringing that occurs when the MOS transistor Q1 is turned on.

[0030] In one embodiment, a first pull-up resistor R9, a second pull-up resistor R10, and a third pull-up resistor R13 may also be provided in the three-phase overcurrent detection circuit. The first end of the first pull-up resistor R9 provided in the comparison module is electrically connected to the positive electrode of the power supply, and the second end of the first pull-up resistor R9 is electrically connected to the output end of the comparator U3 in the comparison module. The first end of the second pull-up resistor R10 provided in the trigger module is electrically connected to the positive electrode of the power supply, and the second end of the second pull-up resistor R10 is electrically connected to the third input end of the D-type flip-flop U4 in the trigger module, i.e., the reset pin REST. The first end of the third pull-up resistor R13 provided in the fault output module is electrically connected to the positive electrode of the power supply, and the second end of the third pull-up resistor R13 is electrically connected to the drain of the MOS transistor Q1 in the fault output module. Optionally, a pull-up resistor R3 may also be provided, with the first end of the pull-up resistor R3 electrically connected to the first end of the first bias voltage module, and the second end of the pull-up resistor R3 electrically connected to the first input end of the comparator U3. Specifically, the purpose of setting each pull-up resistor is to provide a stable high-level path to ensure clear output logic.

[0031] See next Figure 3 , Figure 3 A detection flow diagram of a three-phase overcurrent detection circuit provided in an embodiment of this specification is shown.

[0032] See Figure 3 , three-phase overcurrent detection methods include: S301, the three-phase current input module collects current signals during three-phase current operation, and sends the collected current signals to the bias voltage module; S302, the bias voltage module generates a voltage signal based on the current signal, and sends the voltage signal to the comparison module, wherein the voltage signal includes a real-time voltage signal and a voltage threshold signal; S303: When the detection result output by the comparison module indicates that the real-time voltage is greater than the voltage threshold, the trigger module sends a trigger signal to the fault output module; S304: The fault output module generates a fault signal based on the trigger signal.

[0033] In an embodiment of the present specification, the three-phase current input module obtains the current signal input in real time by the three-phase circuit to be tested, and sends the obtained current signal to the bias voltage module. The bias voltage module converts the received current signal into a real-time voltage signal, and simultaneously generates a voltage threshold signal, which is sent together to the comparison module. The comparison module makes a judgment based on the received real-time voltage signal and the voltage threshold signal. When the comparison module generates a detection result, it indicates that the voltage received in real time is greater than the voltage threshold, and an overcurrent phenomenon occurs in the three-phase current, and the detection result is sent to the trigger module. After receiving the detection result, the trigger module sends a trigger signal, stores the detection data, and continuously sends a trigger signal to the fault output module. After receiving the trigger signal, the fault output module outputs a fault signal to indicate that an overcurrent phenomenon occurs at this time. Among them, when the voltage received in real time is not greater than the threshold voltage, the comparison module does not generate a detection result, and the subsequent corresponding trigger module and fault output module do not operate.

[0034] The above is only an exemplary embodiment of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure herein, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any variation, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not recorded in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A three-phase overcurrent detection circuit, characterized in that: The circuit includes a three-phase current input module, a bias voltage module, a comparison module, a trigger module and a fault output module. The three-phase current input module is electrically connected to the bias voltage module, the bias voltage module is electrically connected to the comparison module, the comparison module is electrically connected to the trigger module, and the trigger module is electrically connected to the fault output module.

2. The circuit according to claim 1, wherein: The three-phase current input module includes a filter resistor and a diode, the first end of the filter resistor is electrically connected to a single-phase current of the three-phase current to be measured, the second end of the filter resistor is electrically connected to the first end of the diode, and the second end of the diode is electrically connected to the bias voltage module.

3. The circuit according to claim 2, characterized in that The bias voltage module includes a first bias voltage module and a second bias voltage module, wherein the first end of the first bias voltage module is electrically connected to the second end of the diode, and the second end of the first bias voltage module is grounded; the first end of the second bias voltage module is electrically connected to the comparison module, and the second end of the second bias voltage module is grounded.

4. The circuit according to claim 3, characterized in that The first bias voltage module includes a first voltage-dividing resistor module and a first voltage follower. The input end of the first voltage follower is electrically connected to the first voltage-dividing resistor module, and the output end of the first voltage follower is electrically connected to the first input end of the comparison module.

5. The circuit according to claim 3, characterized in that The second bias voltage module includes a second voltage-dividing resistor module and a second voltage follower. The input end of the second voltage follower is electrically connected to the second voltage-dividing resistor module, and the output end of the second voltage follower is electrically connected to the second input end of the comparison module.

6. The circuit according to claim 1, wherein: The comparison module includes a first filter capacitor and a comparator, wherein a first end of the first filter capacitor is electrically connected to an input end of the comparator, a second end of the first filter capacitor is grounded, and an output end of the comparator is electrically connected to the trigger module.

7. The circuit according to claim 1, wherein: The trigger module includes a second filter capacitor and a D-type trigger, the first input end of the D-type trigger is electrically connected to the comparison module, the output end of the D-type trigger is electrically connected to the fault output module, the first end of the second filter capacitor is electrically connected to the second input end of the D-type trigger, and the second end of the second filter capacitor is grounded.

8. The circuit according to claim 7, characterized in that The trigger module further includes a reset button, a first end of the reset button is electrically connected to the third input end of the D-type trigger, and a second end of the reset button is grounded.

9. The circuit according to claim 1, wherein: The fault output module includes a MOS tube and a gate resistor. The first end of the gate resistor is electrically connected to the trigger module, the second end of the gate resistor is connected to the gate of the MOS tube, and the source of the MOS tube is grounded.

10. The circuit according to claim 1, wherein: The circuit also includes a first pull-up resistor, a second pull-up resistor and a third pull-up resistor, wherein the first end of the first pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the first pull-up resistor is electrically connected to the output end of the comparison module, the first end of the second pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the second pull-up resistor is electrically connected to the input end of the trigger module, the first end of the third pull-up resistor is electrically connected to the positive pole of the power supply, and the second end of the third pull-up resistor is electrically connected to the output end of the fault output module.

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