Three-phase power supply reverse phase detection circuit and air conditioner

Abstract

The application relates to a three-phase power supply reverse phase detection circuit and an air conditioner. The circuit comprises a timing trigger module, three input ends of the timing trigger module are connected with three output ends of a three-phase power supply respectively, an output end of the timing trigger module is connected with an input end of an MCU module, and the timing trigger module is used for determining a detection time; a reverse phase detection module, input ends of the reverse phase detection module are connected with the three output ends of the three-phase power supply respectively, an output end of the reverse phase detection module is connected with the input end of the MCU module, and the reverse phase detection module is used for detecting a first phase-to-phase current difference, a second phase-to-phase current difference and a third phase-to-phase current difference; and an MCU module, which is used for outputting a reverse phase fault code of the three-phase power supply in the case that the three-phase power supply exists a reverse phase fault according to the first phase-to-phase current difference, the second phase-to-phase current difference and the third phase-to-phase current difference at a first time, a second time and a third time. The application solves the technical problem that a three-phase power supply cannot be accurately judged whether a reverse phase fault exists.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a three-phase power supply reverse phase detection circuit and an air conditioner. Background Technology

[0002] When a three-phase power supply is connected to a circuit, it may be in reverse phase, which can damage downstream loads. Current technology lacks an independent reverse phase detection circuit to address faults such as motor reversal and starting failure when a three-phase power supply is in reverse phase. Therefore, an independent three-phase power supply reverse phase detection circuit is needed to accurately determine whether a three-phase power supply is in reverse phase. Summary of the Invention

[0003] This application provides a three-phase power supply reverse phase detection circuit and an air conditioner to solve the technical problem of being unable to accurately determine whether a three-phase power supply has a reverse phase fault.

[0004] In a first aspect, this application provides a three-phase power supply reverse phase detection circuit, comprising: a timing trigger module, wherein the three input terminals of the timing trigger module are respectively connected to the three output terminals of the three-phase power supply, and the output terminal of the timing trigger module is connected to the input terminal of an MCU module, the timing trigger module being used to determine the detection time, wherein the detection time includes a first time, a second time, and a third time; and a reverse phase detection module, wherein the input terminals of the reverse phase detection module are respectively connected to the three output terminals of the three-phase power supply, and the output terminal of the reverse phase detection module is connected to the input terminal of the MCU module, the reverse phase detection module being used to detect the third phase of the three-phase power supply. The first phase-to-phase current difference between the first and second output terminals, the second phase-to-phase current difference between the second and third output terminals of the three-phase power supply, and the third phase-to-phase current difference between the third and first output terminals of the three-phase power supply are input to the MCU module. The MCU module is used to output a reverse phase fault code of the three-phase power supply when it is determined that there is a reverse phase fault in the three-phase power supply based on the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference at the first, second, and third time points.

[0005] Secondly, this application provides an air conditioner, comprising: a timing trigger module, wherein the three input terminals of the timing trigger module are respectively connected to the three output terminals of the three-phase power supply of the air conditioner, and the output terminal of the timing trigger module is connected to the input terminal of an MCU module, the timing trigger module being used to determine a detection time, wherein the detection time includes a first time, a second time, and a third time; and a reverse phase detection module, wherein the input terminal of the reverse phase detection module is connected to the output terminal of the three-phase power supply, and the output terminal of the reverse phase detection module is connected to the input terminal of the MCU module, the reverse phase detection module being used to detect the first output terminal and the... The first phase-to-phase current difference at the second output terminal, the second phase-to-phase current difference between the second and third output terminals of the three-phase power supply, and the third phase-to-phase current difference between the third and first output terminals of the three-phase power supply are input to the MCU module. The MCU module is used to output a reverse phase fault code of the three-phase power supply when it is determined that there is a reverse phase fault in the three-phase power supply based on the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference at the first, second, and third time points.

[0006] As an optional example, the timing trigger module includes: a first comparator, the non-inverting input of which is connected to the first output of the three-phase power supply, the inverting input of which is connected to the second output of the three-phase power supply, and the output of which is connected to the D input of a D flip-flop and the first input of an AND gate; a second comparator, the non-inverting input of which is connected to the second output of the three-phase power supply, the inverting input of which is connected to the third output of the three-phase power supply, and the output of which is connected to the CLR terminal of the D flip-flop; a third comparator, the non-inverting input of which is connected to the third output of the three-phase power supply, the inverting input of which is connected to the first output of the three-phase power supply, and the output of which is connected to the second input of the AND gate; the D flip-flop, the Q terminal of which is connected to the third input of the AND gate; and the AND gate, the output of which is connected to the input of the MCU module.

[0007] As an optional example, the timing trigger module is further configured to determine the first moment when the output of the first comparator is high, the output of the second comparator changes from low to high, the output of the third comparator is high, and the current input to the non-inverting input of the second comparator is equal to the current input to the inverting input of the second comparator. The second moment is defined as the moment when the first moment has elapsed for one-third of a target cycle, and the third moment is defined as the moment when the second moment has elapsed for one-third of a target cycle. The target cycle is defined as the cycle of the three-phase current of the three-phase power supply.

[0008] As an optional example, the above-mentioned reverse phase detection module includes: a first detection submodule, wherein a first input terminal of the first detection submodule is connected to a first output terminal of the three-phase power supply, a second input terminal of the first detection submodule is connected to a second output terminal of the three-phase power supply, and an output terminal of the first detection submodule is connected to an input terminal of the MCU module, and the first detection submodule is used to detect the first phase-to-phase current difference; a second detection submodule, wherein a first input terminal of the second detection submodule is connected to a second output terminal of the three-phase power supply, a second input terminal of the second detection submodule is connected to a third output terminal of the three-phase power supply, and an output terminal of the second detection submodule is connected to an input terminal of the MCU module, and the second detection submodule is used to detect the second phase-to-phase current difference; and a third detection submodule, wherein a first input terminal of the third detection submodule is connected to a third output terminal of the three-phase power supply, a second input terminal of the third detection submodule is connected to a first output terminal of the three-phase power supply, and an output terminal of the third detection submodule is connected to an input terminal of the MCU module, and the third detection submodule is used to detect the third phase-to-phase current difference.

[0009] As an optional example, the first detection submodule is further configured to output a high level when the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is high; output a low level when the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is low; and output zero when the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is zero.

[0010] As an optional example, the first detection submodule includes: a first difference unit, the first input terminal of which is connected to the first output terminal of the three-phase power supply, the second input terminal of which is connected to the second output terminal of the three-phase power supply, and the output terminal of which is connected to the input terminal of a first bias unit, the first difference unit including a first operational amplifier and at least one resistor; and a first bias unit, the output terminal of which is connected to the input terminal of the MCU module, the first bias unit including a second operational amplifier, at least one resistor, and at least one capacitor.

[0011] As an optional example, the MCU module is further configured to determine that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply when, at the first moment, the first phase-to-phase current difference is low, the second phase-to-phase current difference is high, and the third phase-to-phase current difference is zero, and at the second moment, the first phase-to-phase current difference is high, the second phase-to-phase current difference is zero, and the third phase-to-phase current difference is low, and output a first reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply.

[0012] As an optional example, the MCU module is further configured to determine that there is a reverse phase fault between the second output terminal and the third output terminal of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high at the second time point, and the first phase current difference is low, the second phase current difference is high, and the third phase current difference is zero at the third time point, and output a second reverse phase fault code indicating that there is a reverse phase fault between the second output terminal and the third output terminal of the three-phase power supply.

[0013] As an optional example, the MCU module is further configured to determine that there is a reverse phase fault between the first output terminal and the third output terminal of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high, and when the first phase current difference is high, the second phase current difference is zero, and the third phase current difference is low, and output a third reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the third output terminal of the three-phase power supply.

[0014] In this embodiment, a timing trigger module is employed. The three input terminals of the timing trigger module are respectively connected to the three output terminals of the three-phase power supply, and the output terminal of the timing trigger module is connected to the input terminal of the MCU module. The timing trigger module is used to determine the detection time, which includes a first time, a second time, and a third time. A reverse phase detection module is also employed. The input terminals of the reverse phase detection module are respectively connected to the three output terminals of the three-phase power supply, and the output terminal of the reverse phase detection module is connected to the input terminal of the MCU module. The reverse phase detection module is used to detect the first phase-to-phase current difference between the first and second output terminals of the three-phase power supply, the second phase-to-phase current difference between the second and third output terminals of the three-phase power supply, and the third phase-to-phase current difference between the third and first output terminals of the three-phase power supply. The module then records the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference. The phase-to-phase current difference is input to the aforementioned MCU module. The aforementioned MCU module is a circuit used to output a reverse phase fault code for the three-phase power supply when it is determined that a reverse phase fault exists in the three-phase power supply based on the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference at the first, second, and third time points. In the aforementioned circuit, the current difference between two phases in the three-phase power supply is detected and input to the MCU module. The MCU module compares the actual current difference between two phases collected with the current difference between two phases generated when the three-phase power supply is connected to the circuit in the forward phase, thereby accurately determining whether the power supply is in reverse phase. When it is determined that a reverse phase fault exists in the three-phase power supply, the corresponding reverse phase fault code is output, thereby achieving the purpose of accurately determining whether a reverse phase fault exists in the three-phase power supply and solving the technical problem of not being able to accurately determine whether a reverse phase fault exists in the three-phase power supply. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1This is a structural diagram of an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application;

[0019] Figure 2 This is a circuit diagram of an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application;

[0020] Figure 3 This is a timing trigger circuit diagram of an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application;

[0021] Figure 4 This is a waveform diagram of the three-phase current when the three-phase power supply is in the positive phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0022] Figure 5 This is a waveform diagram of the phase-to-phase current difference of a three-phase power supply in the positive phase according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0023] Figure 6 This is a waveform diagram of the three-phase current when the first and second terminals of the three-phase power supply are out of phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0024] Figure 7 This is a waveform diagram of the phase-to-phase current difference when the first and second terminals of a three-phase power supply are out of phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0025] Figure 8 This is a waveform diagram of the three-phase current when the second and third terminals of the three-phase power supply are out of phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0026] Figure 9 This is a waveform diagram of the phase-to-phase current difference when the second and third terminals of a three-phase power supply are out of phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0027] Figure 10 This is a waveform diagram of the three-phase current when the third terminal of the three-phase power supply is out of phase with the first terminal, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0028] Figure 11 This is a waveform diagram of the phase-to-phase current difference when the third and first terminals of a three-phase power supply are out of phase, according to an optional three-phase power supply reverse phase detection circuit according to an embodiment of this application.

[0029] Figure 12 This is a schematic diagram of an optional air conditioner according to an embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0032] According to a first aspect of the embodiments of this application, a three-phase power supply reverse phase detection circuit is provided, optionally, as follows: Figure 1 As shown, the circuit described above includes:

[0033] The timing trigger module 102 has three input terminals connected to the three output terminals of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The timing trigger module is used to determine the detection time, which includes the first time, the second time, and the third time.

[0034] The reverse phase detection module 104 has its input terminals connected to the three output terminals of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The reverse phase detection module is used to detect the first phase current difference between the first and second output terminals of the three-phase power supply, the second phase current difference between the second and third output terminals of the three-phase power supply, and the third phase current difference between the third and first output terminals of the three-phase power supply, and inputs the first phase current difference, the second phase current difference, and the third phase current difference to the MCU module.

[0035] MCU module 106 is used to output a reverse phase fault code of the three-phase power supply when it is determined that there is a reverse phase fault in the three-phase power supply based on the current difference between the first phase, the current difference between the second phase, and the current difference between the third phase at the first time, the second time, and the third time.

[0036] Optionally, in this embodiment, the circuit diagram of the three-phase power supply reverse phase detection circuit is as follows: Figure 2As shown, the power supply reverse phase detection circuit includes a timing trigger module, a reverse phase detection module, and an MCU module. The three input terminals of the timing trigger module are connected to the three output terminals of the three-phase power supply, and the output terminal of the timing trigger module is connected to the input terminal of the MCU module. The input terminals of the reverse phase detection module are also connected to the three output terminals of the three-phase power supply, and the output terminal of the reverse phase detection module is connected to the input terminal of the MCU module. The timing trigger module and the reverse phase detection module are connected in parallel. The timing trigger module determines the first, second, and third moments for detecting the interphase current difference of the three-phase power supply. This allows the reverse phase detection module to sample the first interphase current difference between the first and second output terminals, the second interphase current difference between the second and third output terminals, and the third interphase current difference between the third and first output terminals at these moments. Data from other moments is invalid. A total of three cycles are collected to avoid continuous output of invalid data affecting the detection circuit's output results. The first, second, and third interphase current differences are then input to the MCU module. The MCU module compares the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference with the phase-to-phase current difference of each phase when the three-phase power supply is connected to the circuit in the positive phase. This allows it to accurately determine whether the three-phase power supply has a reverse phase fault. If a reverse phase fault is determined, the module outputs a reverse phase fault code for the three-phase power supply, thus providing an accurate understanding of the input status of the three-phase power supply.

[0037] As an optional example, the timed trigger module includes:

[0038] The first comparator has its non-inverting input connected to the first output of the three-phase power supply, its inverting input connected to the second output of the three-phase power supply, and its output connected to the D input of a D flip-flop and the first input of an AND gate, respectively.

[0039] The second comparator has its non-inverting input connected to the second output of the three-phase power supply, its inverting input connected to the third output of the three-phase power supply, and its output connected to the CLR terminal of the D flip-flop.

[0040] The third comparator has its non-inverting input connected to the third output of the three-phase power supply, its inverting input connected to the first output of the three-phase power supply, and its output connected to the second input of the AND gate.

[0041] A D flip-flop, the Q input of which is connected to the third input of an AND gate;

[0042] The output of the AND gate is connected to the input of the MCU module.

[0043] Optionally, in this embodiment, the timing trigger circuit diagram is as follows: Figure 3 As shown, the timing trigger module includes a first comparator U11, a second comparator U12, a third comparator U13, a D flip-flop, and an AND gate Y. The non-inverting input of the first comparator U11 is connected to the first output L1 of the three-phase power supply, and the inverting input is connected to the second output L2 of the three-phase power supply. The output of the first comparator U11 is connected to the D input of the D flip-flop and the first input of the AND gate Y. The non-inverting input of the second comparator U12 is connected to the second output L2 of the three-phase power supply, and the inverting input is connected to the third output L3 of the three-phase power supply. The output of the second comparator U12 is connected to the CLR terminal of the D flip-flop. The non-inverting input of the third comparator U13 is connected to the third output L3 of the three-phase power supply, and the inverting input is connected to the first output L1 of the three-phase power supply. The output of the third comparator U13 is connected to the second input of the AND gate. The Q terminal of the D flip-flop is connected to the third input of the AND gate Y. The output of the AND gate Y is connected to the input of the MCU module.

[0044] As an optional example, the timing trigger module is also used to determine the moment as the first moment when the output of the first comparator is high, the output of the second comparator changes from low to high, the output of the third comparator is high, and the current input to the non-inverting input of the second comparator is equal to the current input to the inverting input of the second comparator. The moment when the first moment elapses for one-third of a target cycle is the second moment, and the moment when the second moment elapses for one-third of a target cycle is the third moment, where the target cycle is the cycle of the three-phase current of the three-phase power supply.

[0045] Optionally, in this embodiment, the first output terminal L1, the second output terminal L2, and the third output terminal L3 of the three-phase power supply are detected by the respective phase current sensors, and the outputs are IU, IV, and IW, respectively. The three-phase current waveforms when the three-phase power supply is in positive phase are shown below. Figure 4 As shown, when IU>IV=IW, i.e., the first time t1, the first comparator U11 and the third comparator U13 output high level, the output of the second comparator U12 changes from low level 0 to high level 1, the CLR terminal of the D flip-flop is triggered by the rising edge, the Q output is high level 1, and the logic AND gate outputs high level Y=1. At this time, the timing trigger module determines that this moment is the first time t1. After that, the current difference between the two phases at this moment is collected every one-third of the cycle, i.e. the second time t2 and the third time t3. The current difference data between the two phases at other times is invalid. A total of 3 cycles are collected. The first cycle is t1, t2, t3, the second cycle is t4, t5, t6, and the first cycle is t7, t8, t9.

[0046] As an optional example, the inverse phase detection module includes:

[0047] The first detection submodule has its first input terminal connected to the first output terminal of the three-phase power supply, its second input terminal connected to the second output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The first detection submodule is used to detect the first phase current difference.

[0048] The second detection submodule has its first input terminal connected to the second output terminal of the three-phase power supply, its second input terminal connected to the third output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The second detection submodule is used to detect the current difference between the second phases.

[0049] The third detection submodule has its first input terminal connected to the third output terminal of the three-phase power supply, its second input terminal connected to the first output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The third detection submodule is used to detect the current difference between the third phases.

[0050] Optionally, in this embodiment, as Figure 2 As shown, the reverse phase detection module includes a first detection submodule, a second detection submodule, and a third detection submodule. The first input terminal of the first detection submodule is connected to the first output terminal L1 of the three-phase power supply, the second input terminal of the first detection submodule is connected to the second output terminal L2 of the three-phase power supply, and the output terminal of the first detection submodule is connected to the input terminal of the MCU module. The first input terminal of the second detection submodule is connected to the second output terminal L2 of the three-phase power supply, the second input terminal of the second detection submodule is connected to the third output terminal L3 of the three-phase power supply, and the output terminal of the second detection submodule is connected to the input terminal of the MCU module. The first input terminal of the third detection submodule is connected to the third output terminal L3 of the three-phase power supply, the second input terminal of the third detection submodule is connected to the first output terminal L1 of the three-phase power supply, and the output terminal of the third detection submodule is connected to the input terminal of the MCU module. IU and IV are input to the first detection submodule, which detects the first phase-to-phase current difference between L1 and L2. IV and IW are input to the second detection submodule, which detects the second phase-to-phase current difference between L2 and L3. IW and IU are input to the third detection submodule, which detects the third phase-to-phase current difference between L1 and L3.

[0051] As an optional example, the first detection submodule is further configured to output a high level when the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is high; output a low level when the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is low; and output zero when the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is zero.

[0052] Optionally, in this embodiment, if the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, the first detection submodule outputs a high level to determine that the first phase-to-phase current difference is high. If the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, the first detection submodule outputs a low level to determine that the first phase-to-phase current difference is low. If the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, the first detection submodule outputs zero to determine that the first phase-to-phase current difference is zero. If the current output from the second terminal of the three-phase power supply is higher than the current output from the third terminal of the three-phase power supply, the second detection submodule outputs a high level to determine that the second phase-to-phase current difference is high. If the current output from the second terminal of the three-phase power supply is lower than the current output from the third terminal of the three-phase power supply, the second detection submodule outputs a low level to determine that the second phase-to-phase current difference is low. If the current output from the second terminal of the three-phase power supply is equal to the current output from the third terminal of the three-phase power supply, the second detection submodule outputs zero to determine that the second phase-to-phase current difference is zero. If the current output from the third terminal of the three-phase power supply is higher than the current output from the first terminal, the third detection submodule outputs a high level, confirming that the current difference between the third phases is high. If the current output from the third terminal of the three-phase power supply is lower than the current output from the first terminal of a single phase, the third detection submodule outputs a low level, confirming that the current difference between the third phases is low. If the current output from the third terminal of the three-phase power supply is equal to the current output from the first terminal, the third detection submodule outputs zero, confirming that the current difference between the third phases is zero.

[0053] As an optional example, the first detection submodule includes:

[0054] The first difference unit has a first input terminal connected to the first output terminal of the three-phase power supply, a second input terminal connected to the second output terminal of the three-phase power supply, and an output terminal connected to the input terminal of the first bias unit. The first difference unit includes a first operational amplifier and at least one resistor.

[0055] The first bias unit has its output connected to the input of the MCU module. The first bias unit includes a second operational amplifier, at least one resistor, and at least one capacitor.

[0056] Optionally, in this embodiment, the first detection submodule includes a first difference unit and a first bias unit, the second detection submodule includes a second difference unit and a second bias unit, and the third detection submodule includes a third difference unit and a third bias unit. For example... Figure 2 As shown, the first difference calculation unit consists of a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier U1. The first operational amplifier U1 is powered by a dual power supply and can output a negative voltage signal. The first bias unit consists of a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, a second capacitor C2, and a second operational amplifier U2. The output of the first operational amplifier U1 is biased within the input voltage range of the MCU module. The output of the second operational amplifier U2 is connected to the MCU module, enabling the MCU module to detect the difference between the two-phase currents. The ninth resistor R9 and the third capacitor C3 constitute the first filter module, ensuring the accuracy of the output signal of the second operational amplifier U2. The second difference unit consists of resistors R10 (10th), R11 (11th), R12 (12th), and R13 (13th) and operational amplifier U3. The second bias unit consists of resistors R14 (14th), R15 (15th), R16 (16th), R17 (17th), capacitors C4 (4th), C5 (5th), and operational amplifier U4. Resistor R18 (18th) and capacitor C6 (6th) constitute the second filter module. The third difference unit consists of resistors R19 (19th), R20 (20th), R21 (21st), and R22 (22nd) and operational amplifier U5. The second bias unit consists of resistors R23 (23rd), R24 (24th), R25 (25th), R26 (26th), capacitors C7 (7th), C8 (8th), and operational amplifier U6. Resistor R27 (27th) and capacitor C9 (9th) constitute the third filter module.

[0057] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply when, at a first moment, the first phase current difference is low, the second phase current difference is high, and the third phase current difference is zero, and at a second moment, the first phase current difference is high, the second phase current difference is zero, and the third phase current difference is low, and output a first reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply.

[0058] Optionally, in this embodiment, when the three-phase power supply is connected to the circuit in positive phase, the three-phase current waveform is as follows: Figure 4 As shown, the waveform of the phase-to-phase current difference in the positive phase of a three-phase power supply is as follows: Figure 5As shown, at the first time t1, the first phase current difference Iuv is high, the second phase current difference Ivw is zero, and the third phase current difference Iwu is low. At the second time t2, the first phase current difference Iuv is low, the second phase current difference Ivw is high, and the third phase current difference Iwu is zero. At the third time t3, the first phase current difference Iuv is zero, the second phase current difference Ivw is low, and the third phase current difference Iwu is high. When the first output terminal L1 and the second output terminal L2 of the three-phase power supply are connected to the circuit in reverse phase, the three-phase current waveforms are as follows. Figure 6 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 7 As shown, at the first time t1, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At the second time t2, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At the third time t3, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At this time, the MCU module detects a reverse phase fault between the first output terminal L1 and the second output terminal L2 of the three-phase power supply and outputs a first reverse phase fault code indicating a reverse phase fault between the first output terminal L1 and the second output terminal L2 of the three-phase power supply.

[0059] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the second and third output terminals of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high at a second time, and the first phase current difference is low, the second phase current difference is high, and the third phase current difference is zero at a third time, and output a second reverse phase fault code indicating that there is a reverse phase fault between the second and third output terminals of the three-phase power supply.

[0060] Optionally, in this embodiment, when the second output terminal L2 and the third output terminal L3 of the three-phase power supply are connected to the circuit in reverse phase, the three-phase current waveform is as follows: Figure 8 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 9As shown, at the first time t1, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At the second time t2, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At the third time t3, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At this time, the MCU module detects a reverse phase fault between the second output terminal L2 and the third output terminal L3 of the three-phase power supply and outputs a second reverse phase fault code indicating a reverse phase fault between the second output terminal L2 and the third output terminal L3 of the three-phase power supply.

[0061] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the first and third output terminals of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high, and at the third moment, the first phase current difference is high, the second phase current difference is zero, and the third phase current difference is low, and output a third reverse phase fault code indicating that there is a reverse phase fault between the first and third output terminals of the three-phase power supply.

[0062] Optionally, in this embodiment, when the third output terminal L3 of the three-phase power supply is connected to the circuit in reverse phase with the first output terminal L1, the three-phase current waveform is as follows: Figure 10 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 11 As shown, at the first time t1, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At the second time t2, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At the third time t3, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At this time, the MCU module detects a reverse phase fault between the third output terminal L3 and the first output terminal L1 of the three-phase power supply, and outputs a third reverse phase fault code indicating that the third output terminal L3 and the first output terminal L1 of the three-phase power supply are in reverse phase.

[0063] To illustrate with an example, this application relates to a three-phase power supply reverse phase detection circuit. By detecting the current difference between two phases of the three-phase power supply and comparing it with the output signal when the three-phase power supply is connected in the forward phase, it can accurately determine whether the input three-phase power supply is in reverse phase and output a corresponding three-phase power supply reverse phase fault code, thereby accurately determining the condition of the input three-phase power supply. Figure 2This is a circuit diagram for a three-phase power supply reverse phase detection. The three-phase power supplies L1, L2, and L3 are detected by current sensors for each phase, with outputs of IU, IV, and IW respectively. These output signals are then input to a timing trigger circuit and a power supply reverse phase detection circuit. When IU > IV = IW, i.e., at time t1, comparators U11 and U13 output high levels, and the output of U12 changes from low level 0 to high level 1. The D flip-flop's CLR terminal is triggered on the rising edge, and the Q output is high level 1. The AND gate outputs high level Y = 1. At this time, the timing trigger circuit performs initial signal acquisition (t = t1). Afterward, it acquires the current difference between the two phases every 1 / 3 of a cycle. Current difference data between the two phases at other times are invalid. A total of 3 cycles are acquired (t = t9). Inputs IU and IV are sent to the first detection circuit, inputs IV and IW are sent to the second detection circuit, and inputs IW and IU are sent to the third detection circuit. In the first detection circuit, resistors R1, R2, R3, and R4, along with operational amplifier U1, form a difference circuit. U1 is powered by a dual power supply and can output a negative voltage signal. Resistors R5, R6, R7, and R8, capacitors C1 and C2, and operational amplifier U2 form a bias circuit, biasing the output of U1 within the input voltage range of the MCU module. The output of U2 is connected to the MCU module. This allows the MCU module to detect the current difference between the two phases. R9 and C3 form a filter circuit to ensure the accuracy of the output signal of operational amplifier U2, thereby accurately determining whether there is a reverse phase in the three phases. Figure 3 For the timing trigger circuit, comparators U11, U12, and U13 are connected to the logic circuit. When IU > IV = IW, t = t1. At this time, U11 and U13 output a high level 1, and the output of U12 changes from a low level 0 to a high level 1. The CLR terminal of the D flip-flop is triggered on the rising edge, and the Q output is a high level 1. This high level is input to the MCU module. The MCU module locks the high level state at time t1, and starting from time t1, every 1 / 3 cycle, the MCU collects the waveform of the two-phase current difference (Iuv, Ivw, Iwu) at this time, and compares it with the waveform of the two-phase current difference (Iuv, Ivw, Iwu) when the three-phase power supply is connected in the positive phase to the circuit, so as to determine whether there is a reverse phase situation of the three-phase power supply.

[0064] (Truth table of D flip-flops)

[0065]

[0066] When the three-phase power supply is connected to the circuit in positive phase, the output current waveforms of the U, V, and W phases are as follows: Figure 4As shown, the phase difference between UV, VW, and WU is 1 / 3T at this time. During the time intervals t1-t3, the output voltage signals of the first detection circuit U1 are positive, negative, and 0, respectively. After passing through a bias circuit, these signals are input to the MCU module, which processes them as 1, -1, and 0. During the same time intervals t1-t3, the output voltage signals of the second detection circuit U3 are 0, positive, and negative, respectively. After passing through a bias circuit, these signals are input to the MCU module, which processes them as 0, 1, and -1. During the same time intervals t1-t3, the output voltage signals of the third detection circuit U5 are negative, 0, and positive, respectively. After passing through a bias circuit, these signals are input to the MCU module, which processes them as -1, 0, and 1. t1-t3 constitutes one cycle, and the MCU module needs to detect for three cycles (t = t9). The current waveform between the two phases at any time between t1-t9 is... Figure 5 As shown, the three-phase power supply is in positive phase.

[0067] Optionally, taking the L2 and L3 reverse-phase connection circuit of a three-phase power supply as an example, the three-phase output current waveforms of U, V, and W are as follows: Figure 8 As shown, the phase difference between UV, VW, and WU is 1 / 3T at this time. During the time intervals t1-t3, the output voltage signals of the first detection circuit U1 are positive, 0, and negative, respectively. After passing through the bias circuit, these signals are input to the MCU module, which processes them as 1, 0, and -1. During the same time intervals, the output voltage signals of the second detection circuit U3 are 0, negative, and positive, respectively. After passing through the bias circuit, these signals are input to the MCU module, which processes them as 0, -1, and 1. During the same time intervals, the output voltage signals of the third detection circuit U5 are negative, positive, and 0, respectively. After passing through the bias circuit, these signals are input to the MCU module, which processes them as -1, 1, and 0. t1-t3 constitutes one cycle, and the MCU module detects for three cycles (t = t9). The waveform of the current difference between two phases of the three-phase power supply at any time between t1 and t9 is... Figure 9 As shown, the three-phase power supply has L2 and L3 in reverse phase.

[0068] It should be noted that, for the sake of simplicity, the aforementioned circuit embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0069] According to another aspect of the embodiments of this application, an air conditioner is also provided, such as... Figure 12 As shown, it includes:

[0070] The timing trigger module 1202 has three input terminals connected to the three output terminals of the three-phase power supply of the air conditioner, and the output terminal of the timing trigger module connected to the input terminal of the MCU module. The timing trigger module is used to determine the detection time, which includes the first time, the second time and the third time.

[0071] The reverse phase detection module 1204 has its input terminal connected to the output terminal of the three-phase power supply and its output terminal connected to the input terminal of the MCU module. The reverse phase detection module is used to detect the first phase current difference between the first and second output terminals of the three-phase power supply, the second phase current difference between the second and third output terminals of the three-phase power supply, and the third phase current difference between the third and first output terminals of the three-phase power supply, and inputs the first phase current difference, the second phase current difference, and the third phase current difference to the MCU module.

[0072] MCU module 1206 is used to output a reverse phase fault code of the three-phase power supply when it is determined that there is a reverse phase fault in the three-phase power supply based on the current difference between the first phase, the current difference between the second phase, and the current difference between the third phase at the first time, the second time, and the third time.

[0073] Optionally, in this embodiment, the circuit diagram of the three-phase power supply reverse phase detection circuit is as follows: Figure 2 As shown, the three-phase power supply reverse phase detection circuit includes a timing trigger module, a reverse phase detection module, and an MCU module. The three input terminals of the timing trigger module are connected to the three output terminals of the three-phase power supply, and the output terminal of the timing trigger module is connected to the input terminal of the MCU module. The input terminals of the reverse phase detection module are also connected to the three output terminals of the three-phase power supply, and the output terminal of the reverse phase detection module is connected to the input terminal of the MCU module. The timing trigger module and the reverse phase detection module are connected in parallel. The timing trigger module determines the first, second, and third moments for detecting the interphase current difference of the three-phase power supply. This allows the reverse phase detection module to sample the first interphase current difference between the first and second output terminals, the second interphase current difference between the second and third output terminals, and the third interphase current difference between the third and first output terminals at these moments. Data from other moments is invalid. A total of three cycles are collected to avoid continuous output of invalid data affecting the detection circuit's output results. The first, second, and third interphase current differences are then input to the MCU module. The MCU module compares the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference with the phase-to-phase current difference of each phase when the three-phase power supply is connected to the circuit in the positive phase. This allows it to accurately determine whether the three-phase power supply has a reverse phase fault. If a reverse phase fault is determined, the module outputs a reverse phase fault code for the three-phase power supply, thus providing an accurate understanding of the input status of the three-phase power supply.

[0074] As an optional example, the timed trigger module includes:

[0075] The first comparator has its non-inverting input connected to the first output of the three-phase power supply, its inverting input connected to the second output of the three-phase power supply, and its output connected to the D input of a D flip-flop and the first input of an AND gate, respectively.

[0076] The second comparator has its non-inverting input connected to the second output of the three-phase power supply, its inverting input connected to the third output of the three-phase power supply, and its output connected to the CLR terminal of the D flip-flop.

[0077] The third comparator has its non-inverting input connected to the third output of the three-phase power supply, its inverting input connected to the first output of the three-phase power supply, and its output connected to the second input of the AND gate.

[0078] A D flip-flop, the Q input of which is connected to the third input of an AND gate;

[0079] The output of the AND gate is connected to the input of the MCU module.

[0080] Optionally, in this embodiment, the timing trigger circuit diagram is as follows: Figure 3 As shown, the timing trigger module includes a first comparator U11, a second comparator U12, a third comparator U13, a D flip-flop, and an AND gate Y. The non-inverting input of the first comparator U11 is connected to the first output L1 of the three-phase power supply, and the inverting input is connected to the second output L2 of the three-phase power supply. The output of the first comparator U11 is connected to the D input of the D flip-flop and the first input of the AND gate Y. The non-inverting input of the second comparator U12 is connected to the second output L2 of the three-phase power supply, and the inverting input is connected to the third output L3 of the three-phase power supply. The output of the second comparator U12 is connected to the CLR terminal of the D flip-flop. The non-inverting input of the third comparator U13 is connected to the third output L3 of the three-phase power supply, and the inverting input is connected to the first output L1 of the three-phase power supply. The output of the third comparator U13 is connected to the second input of the AND gate. The Q terminal of the D flip-flop is connected to the third input of the AND gate Y. The output of the AND gate Y is connected to the input of the MCU module.

[0081] As an optional example, the timing trigger module is also used to determine the moment as the first moment when the output of the first comparator is high, the output of the second comparator changes from low to high, the output of the third comparator is high, and the current input to the non-inverting input of the second comparator is equal to the current input to the inverting input of the second comparator. The moment when the first moment elapses for one-third of a target cycle is the second moment, and the moment when the second moment elapses for one-third of a target cycle is the third moment, where the target cycle is the cycle of the three-phase current of the three-phase power supply.

[0082] Optionally, in this embodiment, the first output terminal L1, the second output terminal L2, and the third output terminal L3 of the three-phase power supply are detected by the respective phase current sensors, and the outputs are IU, IV, and IW, respectively. The three-phase current waveforms when the three-phase power supply is in positive phase are shown below. Figure 4 As shown, when IU>IV=IW, i.e., the first time t1, the first comparator U11 and the third comparator U13 output high level, the output of the second comparator U12 changes from low level 0 to high level 1, the CLR terminal of the D flip-flop is triggered by the rising edge, the Q output is high level 1, and the logic AND gate outputs high level Y=1. At this time, the timing trigger module determines that this moment is the first time t1. After that, the current difference between the two phases at this moment is collected every one-third of the cycle, i.e. the second time t2 and the third time t3. The current difference data between the two phases at other times is invalid. A total of 3 cycles are collected. The first cycle is t1, t2, t3, the second cycle is t4, t5, t6, and the first cycle is t7, t8, t9.

[0083] As an optional example, the inverse phase detection module includes:

[0084] The first detection submodule has its first input terminal connected to the first output terminal of the three-phase power supply, its second input terminal connected to the second output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The first detection submodule is used to detect the first phase current difference.

[0085] The second detection submodule has its first input terminal connected to the second output terminal of the three-phase power supply, its second input terminal connected to the third output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The second detection submodule is used to detect the current difference between the second phases.

[0086] The third detection submodule has its first input terminal connected to the third output terminal of the three-phase power supply, its second input terminal connected to the first output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The third detection submodule is used to detect the current difference between the third phases.

[0087] Optionally, in this embodiment, as Figure 2 As shown, the reverse phase detection module includes a first detection submodule, a second detection submodule, and a third detection submodule. The first input terminal of the first detection submodule is connected to the first output terminal L1 of the three-phase power supply, the second input terminal of the first detection submodule is connected to the second output terminal L2 of the three-phase power supply, and the output terminal of the first detection submodule is connected to the input terminal of the MCU module. The first input terminal of the second detection submodule is connected to the second output terminal L2 of the three-phase power supply, the second input terminal of the second detection submodule is connected to the third output terminal L3 of the three-phase power supply, and the output terminal of the second detection submodule is connected to the input terminal of the MCU module. The first input terminal of the third detection submodule is connected to the third output terminal L3 of the three-phase power supply, the second input terminal of the third detection submodule is connected to the first output terminal L1 of the three-phase power supply, and the output terminal of the third detection submodule is connected to the input terminal of the MCU module. IU and IV are input to the first detection submodule, which detects the first phase-to-phase current difference between L1 and L2. IV and IW are input to the second detection submodule, which detects the second phase-to-phase current difference between L2 and L3. IW and IU are input to the third detection submodule, which detects the third phase-to-phase current difference between L1 and L3.

[0088] As an optional example, the first detection submodule is further configured to output a high level when the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is high; output a low level when the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is low; and output zero when the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, thus determining that the current difference between the first phases is zero.

[0089] Optionally, in this embodiment, if the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, the first detection submodule outputs a high level to determine that the first phase-to-phase current difference is high. If the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, the first detection submodule outputs a low level to determine that the first phase-to-phase current difference is low. If the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, the first detection submodule outputs zero to determine that the first phase-to-phase current difference is zero. If the current output from the second terminal of the three-phase power supply is higher than the current output from the third terminal of the three-phase power supply, the second detection submodule outputs a high level to determine that the second phase-to-phase current difference is high. If the current output from the second terminal of the three-phase power supply is lower than the current output from the third terminal of the three-phase power supply, the second detection submodule outputs a low level to determine that the second phase-to-phase current difference is low. If the current output from the second terminal of the three-phase power supply is equal to the current output from the third terminal of the three-phase power supply, the second detection submodule outputs zero to determine that the second phase-to-phase current difference is zero. If the current output from the third terminal of the three-phase power supply is higher than the current output from the first terminal, the third detection submodule outputs a high level, confirming that the current difference between the third phases is high. If the current output from the third terminal of the three-phase power supply is lower than the current output from the first terminal of a single phase, the third detection submodule outputs a low level, confirming that the current difference between the third phases is low. If the current output from the third terminal of the three-phase power supply is equal to the current output from the first terminal, the third detection submodule outputs zero, confirming that the current difference between the third phases is zero.

[0090] As an optional example, the first detection submodule includes:

[0091] The first difference unit has a first input terminal connected to the first output terminal of the three-phase power supply, a second input terminal connected to the second output terminal of the three-phase power supply, and an output terminal connected to the input terminal of the first bias unit. The first difference unit includes a first operational amplifier and at least one resistor.

[0092] The first bias unit has its output connected to the input of the MCU module. The first bias unit includes a second operational amplifier, at least one resistor, and at least one capacitor.

[0093] Optionally, in this embodiment, the first detection submodule includes a first difference unit and a first bias unit, the second detection submodule includes a second difference unit and a second bias unit, and the third detection submodule includes a third difference unit and a third bias unit. For example... Figure 2As shown, the first difference calculation unit consists of a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier U1. The first operational amplifier U1 is powered by a dual power supply and can output a negative voltage signal. The first bias unit consists of a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, a second capacitor C2, and a second operational amplifier U2. The output of the first operational amplifier U1 is biased within the input voltage range of the MCU module. The output of the second operational amplifier U2 is connected to the MCU module, enabling the MCU module to detect the difference between the two-phase currents. The ninth resistor R9 and the third capacitor C3 constitute the first filter module, ensuring the accuracy of the output signal of the second operational amplifier U2. The second difference unit consists of resistors R10 (10th), R11 (11th), R12 (12th), and R13 (13th) and operational amplifier U3. The second bias unit consists of resistors R14 (14th), R15 (15th), R16 (16th), R17 (17th), capacitors C4 (4th), C5 (5th), and operational amplifier U4. Resistor R18 (18th) and capacitor C6 (6th) constitute the second filter module. The third difference unit consists of resistors R19 (19th), R20 (20th), R21 (21st), and R22 (22nd) and operational amplifier U5. The second bias unit consists of resistors R23 (23rd), R24 (24th), R25 (25th), R26 (26th), capacitors C7 (7th), C8 (8th), and operational amplifier U6. Resistor R27 (27th) and capacitor C9 (9th) constitute the third filter module.

[0094] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply when, at a first moment, the first phase current difference is low, the second phase current difference is high, and the third phase current difference is zero, and at a second moment, the first phase current difference is high, the second phase current difference is zero, and the third phase current difference is low, and output a first reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply.

[0095] Optionally, in this embodiment, when the three-phase power supply is connected to the circuit in positive phase, the three-phase current waveform is as follows: Figure 4 As shown, the waveform of the phase-to-phase current difference in the positive phase of a three-phase power supply is as follows: Figure 5As shown, at the first time t1, the first phase current difference Iuv is high, the second phase current difference Ivw is zero, and the third phase current difference Iwu is low. At the second time t2, the first phase current difference Iuv is low, the second phase current difference Ivw is high, and the third phase current difference Iwu is zero. At the third time t3, the first phase current difference Iuv is zero, the second phase current difference Ivw is low, and the third phase current difference Iwu is high. When the first output terminal L1 and the second output terminal L2 of the three-phase power supply are connected to the circuit in reverse phase, the three-phase current waveforms are as follows. Figure 6 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 7 As shown, at the first time t1, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At the second time t2, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At the third time t3, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At this time, the MCU module detects a reverse phase fault between the first output terminal L1 and the second output terminal L2 of the three-phase power supply and outputs a first reverse phase fault code indicating a reverse phase fault between the first output terminal L1 and the second output terminal L2 of the three-phase power supply.

[0096] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the second and third output terminals of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high at a second time, and the first phase current difference is low, the second phase current difference is high, and the third phase current difference is zero at a third time, and output a second reverse phase fault code indicating that there is a reverse phase fault between the second and third output terminals of the three-phase power supply.

[0097] Optionally, in this embodiment, when the second output terminal L2 and the third output terminal L3 of the three-phase power supply are connected to the circuit in reverse phase, the three-phase current waveform is as follows: Figure 8 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 9As shown, at the first time t1, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At the second time t2, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At the third time t3, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At this time, the MCU module detects a reverse phase fault between the second output terminal L2 and the third output terminal L3 of the three-phase power supply and outputs a second reverse phase fault code indicating a reverse phase fault between the second output terminal L2 and the third output terminal L3 of the three-phase power supply.

[0098] As an optional example, the MCU module is also used to determine that there is a reverse phase fault between the first and third output terminals of the three-phase power supply when the first phase current difference is zero, the second phase current difference is low, and the third phase current difference is high, and at the third moment, the first phase current difference is high, the second phase current difference is zero, and the third phase current difference is low, and output a third reverse phase fault code indicating that there is a reverse phase fault between the first and third output terminals of the three-phase power supply.

[0099] Optionally, in this embodiment, when the third output terminal L3 of the three-phase power supply is connected to the circuit in reverse phase with the first output terminal L1, the three-phase current waveform is as follows: Figure 10 As shown, the waveform of the phase-to-phase current difference is as follows: Figure 11 As shown, at the first time t1, the first phase-to-phase current difference Iuv is zero, the second phase-to-phase current difference Ivw is low, and the third phase-to-phase current difference Iwu is high. At the second time t2, the first phase-to-phase current difference Iuv is low, the second phase-to-phase current difference Ivw is high, and the third phase-to-phase current difference Iwu is zero. At the third time t3, the first phase-to-phase current difference Iuv is high, the second phase-to-phase current difference Ivw is zero, and the third phase-to-phase current difference Iwu is low. At this time, the MCU module detects a reverse phase fault between the third output terminal L3 and the first output terminal L1 of the three-phase power supply, and outputs a third reverse phase fault code indicating that the third output terminal L3 and the first output terminal L1 of the three-phase power supply are in reverse phase.

[0100] For other examples of this embodiment, please refer to the examples above, which will not be repeated here.

Claims

1. A three-phase power supply reverse phase detection circuit, characterized in that, include: A timing trigger module, wherein the three input terminals of the timing trigger module are respectively connected to the three output terminals of the three-phase power supply, and the output terminal of the timing trigger module is connected to the input terminal of the MCU module. The timing trigger module is used to determine the detection time, wherein the detection time includes a first time, a second time, and a third time. The reverse phase detection module has its input terminals connected to the three output terminals of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The reverse phase detection module is used to detect the first phase-to-phase current difference between the first and second output terminals of the three-phase power supply, the second phase-to-phase current difference between the second and third output terminals of the three-phase power supply, and the third phase-to-phase current difference between the third and first output terminals of the three-phase power supply, and inputs the first phase-to-phase current difference, the second phase-to-phase current difference, and the third phase-to-phase current difference to the MCU module. The MCU module is configured to output a reverse phase fault code of the three-phase power supply when it is determined that there is a reverse phase fault in the three-phase power supply based on the first phase current difference, the second phase current difference, and the third phase current difference at the first time, the second time, and the third time. The timed trigger module includes: The first comparator has its non-inverting input connected to the first output of the three-phase power supply, its inverting input connected to the second output of the three-phase power supply, and its output connected to the D input of a D flip-flop and the first input of an AND gate, respectively. The second comparator has its non-inverting input connected to the second output of the three-phase power supply, its inverting input connected to the third output of the three-phase power supply, and its output connected to the CLR terminal of the D flip-flop. The third comparator has its non-inverting input connected to the third output of the three-phase power supply, its inverting input connected to the first output of the three-phase power supply, and its output connected to the second input of the AND gate. The Q terminal of the D flip-flop is connected to the third input terminal of the AND gate; The output of the AND gate is connected to the input of the MCU module. The timing trigger module is further configured to determine the first moment when the output of the first comparator is high, the output of the second comparator changes from low to high, the output of the third comparator changes from high, and the current input to the non-inverting input of the second comparator is equal to the current input to the inverting input of the second comparator. The second moment is the moment when the first moment has elapsed for one-third of a target cycle, and the third moment is the moment when the second moment has elapsed for one-third of a target cycle. The target cycle is the cycle of the three-phase current of the three-phase power supply. The MCU module is further configured to determine that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply when, at the first moment, the first phase-to-phase current difference is low, the second phase-to-phase current difference is high, and the third phase-to-phase current difference is zero, and at the second moment, the first phase-to-phase current difference is high, the second phase-to-phase current difference is zero, and the third phase-to-phase current difference is low, and output a first reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the second output terminal of the three-phase power supply. The MCU module is further configured to, at the second moment, when the first phase-to-phase current difference is zero, the second phase-to-phase current difference is low, and the third phase-to-phase current difference is high, and at the third moment, when the first phase-to-phase current difference is low, the second phase-to-phase current difference is high, and the third phase-to-phase current difference is zero, determine that there is a reverse phase fault between the second output terminal and the third output terminal of the three-phase power supply, and output a second reverse phase fault code indicating that there is a reverse phase fault between the second output terminal and the third output terminal of the three-phase power supply.

2. The circuit according to claim 1, characterized in that, The inverse phase detection module includes: The first detection submodule has a first input terminal connected to the first output terminal of the three-phase power supply, a second input terminal connected to the second output terminal of the three-phase power supply, and an output terminal connected to the input terminal of the MCU module. The first detection submodule is used to detect the first phase-to-phase current difference. The second detection submodule has its first input terminal connected to the second output terminal of the three-phase power supply, its second input terminal connected to the third output terminal of the three-phase power supply, and its output terminal connected to the input terminal of the MCU module. The second detection submodule is used to detect the second phase current difference. The third detection submodule has a first input terminal connected to the third output terminal of the three-phase power supply, a second input terminal connected to the first output terminal of the three-phase power supply, and an output terminal connected to the input terminal of the MCU module. The third detection submodule is used to detect the current difference between the third phases.

3. The circuit according to claim 2, characterized in that, The first detection submodule is further configured to: output a high level when the current output from the first terminal of the three-phase power supply is higher than the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is high; output a low level when the current output from the first terminal of the three-phase power supply is lower than the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is low; and output zero when the current output from the first terminal of the three-phase power supply is equal to the current output from the second terminal of the three-phase power supply, thus determining that the first phase current difference is zero.

4. The circuit according to claim 2, characterized in that, The first detection submodule includes: The first difference unit has a first input terminal connected to the first output terminal of the three-phase power supply, a second input terminal connected to the second output terminal of the three-phase power supply, and an output terminal connected to the input terminal of the first bias unit. The first difference unit includes a first operational amplifier and at least one resistor. The first bias unit has its output connected to the input of the MCU module. The first bias unit includes a second operational amplifier, at least one resistor, and at least one capacitor.

5. The circuit according to claim 1, characterized in that, The MCU module is further configured to, at the first moment when the first phase-to-phase current difference is zero, the second phase-to-phase current difference is low, and the third phase-to-phase current difference is high, and at the third moment when the first phase-to-phase current difference is high, the second phase-to-phase current difference is zero, and the third phase-to-phase current difference is low, determine that there is a reverse phase fault between the first output terminal and the third output terminal of the three-phase power supply, and output a third reverse phase fault code indicating that there is a reverse phase fault between the first output terminal and the third output terminal of the three-phase power supply.

6. An air conditioner, characterized in that, The air conditioner includes the three-phase power supply reverse phase detection circuit as described in claim 1.

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