Three-phase detection circuit, air conditioner and detection method

Abstract

The invention discloses a three-phase detection circuit, an air conditioner and a detection method. The three-phase detection circuit comprises a power supply end used for being connected with one phase of a three-phase power supply, a driving end connected with the corresponding phase of a three-phase load, a first voltage dividing unit, a switch unit, a warning unit and an energy storage filtering unit. The input end of the first voltage dividing unit is connected with a first wiring terminal serving as a power supply end; the output end of the first voltage dividing unit is connected with the input end of the switch unit, the output end of the switch unit is connected with the input end of the warning unit and the input end of the energy storage filtering unit, and the output end of the warning unit and the output end of the energy storage filtering unit are both connected with a second wiring terminal serving as a driving end. Whether one phase of the three-phase power supply is correctly connected with the corresponding phase of the three-phase load or not can be independently detected, so that the problem of phase reversal or phase loss of the three-phase load can be effectively avoided through sequential detection, and normal operation of the three-phase load is ensured.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a three-phase detection circuit, an air conditioner and a detection method. Background Art

[0002] The power supply of large commercial air conditioners is usually three-phase 380VAC. Even if the power supply line is correctly wired, workers may still install the air conditioner with the wrong phase sequence. For example, when the installer connects the drive line to the three-phase load (such as compressor, fan, etc.), there may be problems such as reverse phase, missing phase or poor wiring contact. If the phase sequence of the three-phase load is reversed or missing, it may cause the three-phase load to reverse, heat up, and eventually burn out.

[0003] However, in the prior art, two or three phases are usually detected simultaneously to determine whether the current phase of the power supply is correctly connected to the corresponding phase of the three-phase load, but it is impossible to detect whether one phase of the power supply is correctly connected to the corresponding phase of the three-phase load alone.

[0004] Therefore, how to provide a detection circuit that can individually detect whether each phase of the power supply is correctly connected to the corresponding phase of the three-phase load is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a three-phase detection circuit, an air conditioner and a detection method, which are used to solve the problem that the detection circuit in the prior art cannot individually detect whether each phase of the power supply is correctly connected to the corresponding phase of the three-phase load.

[0006] The technical solution of the present invention is a three-phase detection circuit, comprising a power supply end connected to one phase of a three-phase power supply and a driving end connected to a corresponding phase of a three-phase load, the three-phase detection circuit also comprising a first voltage dividing unit, a switch unit, a warning unit and an energy storage filter unit;

[0007] The input end of the first voltage dividing unit is connected to a first wiring terminal, and the first wiring terminal is the power supply end;

[0008] The output end of the first voltage divider unit is connected to the input end of the switch unit, and the output end of the switch unit is respectively connected to the input end of the warning unit and the input end of the energy storage filter unit, and the output end of the warning unit and the output end of the energy storage filter unit are both connected to a second wiring terminal, which is the driving end.

[0009] Furthermore, the three-phase detection circuit also includes a PTC unit arranged between the first wiring terminal and the second wiring terminal.

[0010] Furthermore, the switch unit includes an inductor L1 and a switch coupled to the inductor;

[0011] The first end of the inductor L1 is connected to the input end of the first voltage divider unit, and the second end of the inductor L1 is connected to the input end of the warning unit and the input end of the energy storage filter unit respectively.

[0012] Furthermore, the warning unit includes a light emitting diode D1 and a current limiting resistor R1;

[0013] The positive electrode of the light emitting diode D1 is connected to the output end of the switch unit, the negative electrode of the light emitting diode D1 is connected to the first end of the current limiting resistor R1, and the second end of the current limiting resistor R1 is connected to the second wiring terminal.

[0014] Furthermore, the energy storage filter unit includes a capacitor C1 and a diode D2;

[0015] The first end of the capacitor C1 is connected to the output end of the switch unit, the second end of the capacitor C1 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the second wiring terminal.

[0016] Furthermore, the first voltage dividing unit includes a voltage dividing resistor R2 and a voltage dividing resistor R3 connected in parallel;

[0017] The first end of the voltage-dividing resistor R2 and the first end of the voltage-dividing resistor R3 are both connected to a first wiring terminal, and the second end of the voltage-dividing resistor R2 and the second end of the voltage-dividing resistor R3 are both connected to the input end of the switch unit.

[0018] Furthermore, the three-phase detection circuit also includes a protection unit, and the protection unit includes a bidirectional TVS tube D3;

[0019] The output end of the switch unit is connected to the first end of the bidirectional TVS tube D3, and the second end of the bidirectional TVS tube D3 is connected to the second wiring terminal.

[0020] Furthermore, the three-phase detection circuit further includes a second voltage dividing unit, and the second voltage dividing unit includes a voltage dividing resistor R5 and a voltage dividing resistor R6;

[0021] The first end of the voltage-dividing resistor R5 and the first end of the voltage-dividing resistor R6 are both connected to a third terminal, and the third terminal is also respectively connected to the output end of the warning unit and the output end of the energy storage filter unit; the second end of the voltage-dividing resistor R5 and the second end of the voltage-dividing resistor R6 are both connected to the second terminal.

[0022] Furthermore, a current limiting resistor R4 is connected between the output end of the switch unit and the third wiring terminal.

[0023] The present invention further provides an air conditioner, comprising the three-phase detection circuit described above.

[0024] The present invention also proposes a detection method using the above-mentioned three-phase detection circuit, wherein the three-phase detection circuit includes a power supply end connected to one phase of the three-phase power supply, and a drive end connected to the corresponding phase of the three-phase load; the detection method includes:

[0025] The voltage difference between the power supply end and the drive end is obtained, the voltage difference is compared with a preset voltage, and whether the wiring of the corresponding phase of the three-phase load is correct is determined separately according to the comparison result.

[0026] Further, whether the connection of the corresponding phase of the three-phase load is correct is determined separately according to the comparison result, and the detection method includes:

[0027] If the voltage difference is zero, the PTC unit does not start, and the wiring of the corresponding phase of the three-phase load is correct;

[0028] If the voltage difference is the maximum preset voltage, the PTC unit is activated, and the connection of the corresponding phase of the three-phase load is missing or reversed.

[0029] Further, whether the connection of the corresponding phase of the three-phase load is correct is determined separately according to the comparison result, and the detection method includes:

[0030] Determine whether the voltage difference is greater than a first preset voltage and whether the duration reaches a preset time;

[0031] If not, the warning unit is not activated, and the wiring of the corresponding phase of the three-phase load is correct;

[0032] If so, the warning unit is activated, and the wiring contact of the corresponding phase of the three-phase load is poor.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] The three-phase detection circuit proposed in the present invention can individually detect whether one phase of the three-phase power supply is correctly connected to the corresponding phase of the three-phase load, so as to detect in turn whether the three phases of the three-phase power supply are correctly connected to the corresponding three phases of the three-phase load, effectively avoiding the problem of phase reversal or phase loss in the three-phase load, and further avoiding the problems of reversal and heating of the three-phase load, preventing the three-phase load from burning, and ensuring the normal operation of the three-phase load. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 It is a module block diagram of the three-phase detection circuit proposed by the present invention;

[0038] Figure 2 A circuit diagram of a three-phase detection circuit proposed by the present invention;

[0039] Figure 3 A circuit diagram of another three-phase detection circuit proposed by the present invention;

[0040] Figure 4 This is a flow chart of the detection method of the three-phase detection circuit proposed by the present invention.

[0041] Reference numerals:

[0042] 1. Three-phase power supply;

[0043] 2. Three-phase load;

[0044] 10. A first voltage dividing unit;

[0045] 20.PTC unit;

[0046] 30. Switch unit;

[0047] 40. Warning unit;

[0048] 50. Energy storage filter unit;

[0049] 60. Protection unit;

[0050] 70. A second voltage dividing unit. DETAILED DESCRIPTION

[0051] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described features. In addition, it should be noted that this specification describes many features. Although certain features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0052] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0053] Example 1

[0054] The power supply of large commercial air conditioners is usually three-phase 380VAC. Even if the power supply line is correctly wired, workers may still install the air conditioner with the wrong phase sequence. For example, when the installer connects the drive line to the three-phase load (such as compressor, fan, etc.), there may be problems such as reverse phase, missing phase or poor wiring contact. If the phase sequence of the three-phase load is reversed or missing, it may cause the three-phase load to reverse, heat up, and eventually burn out.

[0055] However, in the prior art, two or three phases are usually detected simultaneously to determine whether the current phase of the power supply is correctly connected to the corresponding phase of the three-phase load, but it is impossible to detect whether one phase of the power supply is correctly connected to the corresponding phase of the three-phase load alone.

[0056] Therefore, in order to solve the above problems, refer to the attached Figure 1-2 The present invention proposes a three-phase detection circuit that can individually detect whether each phase of a three-phase power supply 1 is correctly connected to a corresponding phase of a three-phase load 2, including a power supply end for connecting one phase of the three-phase power supply 1 and a driving end for connecting a corresponding phase of the three-phase load 2. The three-phase detection circuit also includes a first voltage dividing unit 10, a switch unit 30, an alarm unit 40 and an energy storage filter unit 50;

[0057] The input end of the first voltage dividing unit 10 is connected to a first wiring terminal A, and the first wiring terminal A is a power supply end;

[0058] The output end of the first voltage divider unit 10 is connected to the input end of the switch unit 30, and the output end of the switch unit 30 is respectively connected to the input end of the warning unit 40 and the input end of the energy storage filter unit 50, and the output end of the warning unit 40 and the output end of the energy storage filter unit 50 are both connected to the second terminal B, which is the driving end.

[0059] It should be noted that the three phases of the three-phase power supply 1 in this embodiment are all correctly connected by default, and there is no poor contact.

[0060] The three-phase detection circuit is also provided with a main control MCU (not shown, the same throughout the text), and a voltage detection unit is provided in the main control MCU; the voltage of the three-phase power supply 1 is 380VAC.

[0061] Therefore, when the power supply end is connected to one phase of the three-phase power supply 1 and the driving end is correctly connected to the corresponding phase of the three-phase load 2, the phase and voltage of the power supply end and the driving end in the three-phase detection circuit will be the same, so that no current will flow through the entire three-phase detection circuit, that is, the warning unit 40 will not start.

[0062] When the power supply end is connected to one phase of the three-phase power supply 1 and the driving end is connected to the corresponding phase of the three-phase load 2 and a phase loss or reverse phase occurs, there will be an alternating voltage difference of ±380V between the power supply end and the driving end in the three-phase detection circuit, which will cause a current of more than 50mA to flow through the three-phase detection circuit, causing the switch unit 30 to disconnect, thereby cutting off the power to the three-phase load 2, thereby realizing circuit protection for the entire three-phase detection circuit.

[0063] Therefore, the three-phase detection circuit proposed in the present invention can individually detect whether one phase of the three-phase power supply 1 is correctly connected to the corresponding phase of the three-phase load 2, so as to detect in turn whether the three phases of the three-phase power supply 1 are correctly connected to the corresponding three phases of the three-phase load 2, effectively avoiding the problem of reverse phase or phase loss in the three-phase load 2, and further avoiding the problems of reversal, heating, etc. of the three-phase load 2, preventing the three-phase load 2 from burning, and ensuring the normal operation of the three-phase load 2.

[0064] It should be noted that the three-phase detection circuit proposed in this embodiment can only detect whether one phase of the three-phase power supply 1 and the corresponding phase of the three-phase load 2 are correctly connected. Therefore, it can be detected three times in turn to detect whether the three phases between the three-phase power supply 1 and the three-phase load 2 are correctly connected in turn; or, three three-phase detection circuits are used at the same time to simultaneously detect whether the three phases between the three-phase load 2 and the three-phase power supply 1 are correctly connected. And the correct connection proposed in this article means that there is no phase loss or reverse phase between one phase of the three-phase power supply 1 and the corresponding phase of the three-phase load 2.

[0065] Among them, the three-phase load 2 may also have a problem of poor wiring contact. In order to detect whether the three-phase load 2 has a problem of poor wiring contact, the detection performance of the three-phase detection circuit can be further improved. Figure 1The three-phase detection circuit also includes a PTC unit 20 arranged between the first terminal A and the second terminal B; that is, the input side of the PTC unit 20 is connected to the first terminal A, and the output side of the PTC unit 20 is connected to the second terminal B.

[0066] It should be noted that the PTC unit 20 in this embodiment is a temperature-sensitive resistor, whose resistance value increases with the increase of temperature, so when the PTC unit 20 senses that the temperature exceeds its preset safety threshold, its resistance will increase significantly, thereby limiting the current passing through the PTC unit 20. This increase in resistance helps to reduce the further generation of heat and plays a role in overload protection.

[0067] Therefore, when the power supply end is connected to one phase of the three-phase power supply 1 and the drive end is correctly connected to the corresponding phase of the three-phase load 2, the phase and voltage of the power supply end and the drive end in the three-phase detection circuit will be the same, so that no current will flow through the entire three-phase detection circuit, that is, the PTC unit 20 and the warning unit 40 will not be started.

[0068] When the power supply end is connected to one phase of the three-phase power supply 1 and the driving end is connected to the corresponding phase of the three-phase load 2 and a phase loss or reverse phase occurs, there will be an alternating voltage difference of ±380V between the power supply end and the driving end in the three-phase detection circuit, which will cause a current of more than 50mA to flow through the three-phase detection circuit, causing the switch unit 30 to be disconnected to cut off the power to the three-phase load 2. However, at this time, current still flows through the PTC unit 20, causing the temperature of the circuit where the PTC unit 20 is located to rise, and the PTC unit 20 heats up, causing the temperature of the PTC unit 20 to exceed its preset safety threshold and enter a protection state, so as to achieve circuit protection for the entire three-phase detection circuit.

[0069] When the power supply end is connected to one phase of the three-phase power supply 1, and the driving end is correctly connected to the corresponding phase of the three-phase load 2, but the three-phase load 2 has poor wiring contact, there will be a certain alternating voltage difference between the power supply end and the driving end in the three-phase detection circuit, so the PTC unit 20 is started at this time, but its temperature will not exceed its preset safety threshold, that is, the PTC unit 20 will not enter the protection state. When the voltage difference is not greater than the first preset voltage or the voltage difference is greater than the first preset voltage but the charging time does not reach the preset time, it indicates that the voltage difference at this time is an error within the acceptable range, that is, the three-phase load 2 does not have a problem of poor wiring contact; when the voltage difference is greater than the first preset voltage, the voltage difference will charge the energy storage filter unit 50, and if the charging time reaches the preset time, the energy storage filter unit 50 will supply power to the warning unit 40 to start the warning unit 40 to remind the user that the three-phase load 2 has poor wiring contact, so as to promptly notify the maintenance personnel to check the wiring condition to improve the user's experience.

[0070] Therefore, the three-phase detection circuit proposed in the present invention can individually detect whether one phase of the three-phase power supply 1 is correctly connected to the corresponding phase of the three-phase load 2, so as to detect in turn whether the three phases of the three-phase power supply 1 are correctly connected to the corresponding three phases of the three-phase load 2, effectively avoiding the problems of reverse phase, phase loss or poor wiring contact of the three-phase load 2, and further avoiding the problems of reversal, heating and the like of the three-phase load 2, preventing the three-phase load 2 from burning, and ensuring the normal operation of the three-phase load 2.

[0071] In this embodiment, the reverse phase indicates that one phase of the three-phase power supply 1 connected to the power supply end is different from the corresponding phase of the three-phase load 2 connected to the drive end; the phase loss in this embodiment indicates that one phase of the three-phase power supply 1 is connected to the power supply end, but the drive end is not connected to the corresponding phase of the three-phase load 2; the poor wiring contact in this embodiment indicates that one phase of the three-phase power supply 1 connected to the power supply end is the same as the corresponding phase of the three-phase load 2 connected to the drive end, but the wiring of the corresponding phase of the three-phase load 2 is loose or unstable.

[0072] In order to ensure that the switch unit 30 can be normally opened and closed according to the current in the three-phase detection circuit, refer to the attached Figure 2 , this embodiment proposes a circuit structure of a switch unit 30:

[0073] The switch unit 30 includes an inductor T1 and a switch coupled to the inductor T1;

[0074] A first end of the inductor T1 is connected to an input end of the first voltage dividing unit 10 , and a second end of the inductor T1 is connected to an input end of the warning unit 40 and an input end of the energy storage filter unit 50 , respectively.

[0075] In this way, when the power supply end is connected to one phase of the three-phase power supply 1 and the driving end is connected to the corresponding phase of the three-phase load 2 and a phase loss or reverse phase occurs, there will be an alternating voltage difference of ±380V between the power supply end and the driving end in the three-phase detection circuit, which will cause a current of more than 50mA to flow through the inductor L1, causing the inductor T1 to generate a magnetic field, thereby causing the switch to be disconnected, thereby cutting off the power to the three-phase load 2.

[0076] It should be noted that the switch is any one of a relay, an air switch and a reed switch. Of course, the switch can also be other components that can be turned on and off according to the magnetic field generated by the inductor T1, which is not limited here.

[0077] In order to ensure that the energy storage filter unit 50 can store energy and charge the warning unit 40, refer to the attached Figure 2 , this embodiment proposes a circuit structure of an energy storage filter unit 50:

[0078] The energy storage filter unit 50 includes a capacitor C1 and a diode D2;

[0079] The first end of the capacitor C1 is connected to the second end of the inductor T1 , the second end of the capacitor C1 is connected to the anode of the diode D2 , and the cathode of the diode D2 is connected to the second terminal B.

[0080] In this way, when the power supply end is connected to one phase of the three-phase power supply 1, and the driving end is correctly connected to the corresponding phase of the three-phase load 2, but the three-phase load 2 has poor wiring contact, then there will be a certain alternating voltage difference between the power supply end and the driving end in the three-phase detection circuit. Therefore, the PTC unit 20 is started at this time, but its temperature will not exceed its preset safety threshold, that is, the PTC unit 20 will not enter the protection state; and when the voltage difference is greater than the first preset voltage, the voltage difference will charge the capacitor C1. If the charging time reaches the preset time, the capacitor C1 will supply power to the warning unit 40 to start the warning unit 40, reminding the user that the three-phase load 2 has poor wiring contact, so as to promptly notify the maintenance personnel to check the wiring condition to improve the user experience.

[0081] And the diode D2 can prevent the current from flowing back.

[0082] Among them, refer to the attached Figure 2 , the warning unit 40 includes a light emitting diode D1 and a current limiting resistor R1;

[0083] The anode of the light emitting diode D1 is connected to the second end of the inductor T1 , the cathode of the light emitting diode D1 is connected to the first end of the current limiting resistor R1 , and the second terminal B is connected to the second end of the current limiting resistor R1 .

[0084] In this way, when capacitor C1 starts to charge and the charging time reaches the preset time, capacitor C1 will supply power to light-emitting diode D1 (equivalent to the voltage stored in capacitor C1 being greater than the turn-on voltage of light-emitting diode D1), so that light-emitting diode D1 lights up, reminding the user that the three-phase load 2 has poor wiring contact, so as to promptly notify maintenance personnel to check the wiring condition, thereby improving the user experience.

[0085] It should be noted that, in the present embodiment, the first preset voltage is preferably 50V. Of course, it can also be selected as other values ​​according to actual conditions, which is not limited here.

[0086] Because the typical value of the turn-on voltage of the light-emitting diode D1 is 2V, when there is poor contact between one phase of the three-phase power supply 1 and the corresponding phase of the three-phase load 2, there will be a certain alternating voltage difference between the power supply end and the drive end in the three-phase detection circuit. If the voltage difference exceeds 50V, the capacitor C1 will be charged, and the charging time of the capacitor depends on the size of the resistance and capacitance in the corresponding circuit, usually expressed by the time constant τ=R×C, where R is the resistance and C is the capacitance.

[0087] For ease of understanding, in this embodiment, the resistor is set to 1KΩ and the capacitor is set to 100μF, so the time constant τ is 0.1 seconds, and it takes about 0.5 seconds for the capacitor C1 to charge to 99% of its final voltage, after which the capacitor C1 will discharge to light up the light-emitting diode D1. Therefore, the preset time in this embodiment is 0.5 seconds as an example.

[0088] In order to divide the voltage of one phase of the three-phase power supply 1 to ensure the stable operation of the entire three-phase detection circuit, refer to the attached Figure 2 The three-phase detection circuit of this embodiment further provides a first voltage dividing unit 10, and the first voltage dividing unit 10 includes a voltage dividing resistor R2 and a voltage dividing resistor R3 arranged in parallel;

[0089] The first end of the voltage-dividing resistor R2 and the first end of the voltage-dividing resistor R3 are both connected to the first wiring terminal A, and the second end of the voltage-dividing resistor R2 and the second end of the voltage-dividing resistor R3 are both connected to the first end of the inductor T1.

[0090] In order to prevent the sensitive components in the three-phase detection circuit from being damaged by transient high-voltage pulses or voltage spikes, refer to the attached Figure 2 The three-phase detection circuit of this embodiment further provides a protection unit 60, and the protection unit 60 includes a bidirectional TVS tube D3;

[0091] The second end of the inductor T1 is connected to the first end of the bidirectional TVS tube D3 , and the second end of the bidirectional TVS tube D3 is connected to the second terminal B.

[0092] In order to ensure that the entire three-phase detection circuit can operate more stably, refer to the attached Figure 3 The three-phase detection circuit of this embodiment further provides a second voltage dividing unit 70, and the second voltage dividing unit 70 includes a voltage dividing resistor R5 and a voltage dividing resistor R6;

[0093] The first end of the voltage-dividing resistor R5 and the first end of the voltage-dividing resistor R6 are both connected to a third wiring terminal C, and the third wiring terminal C is also respectively connected to the second end of the current-limiting resistor R1, the cathode of the diode D2, and the second end of the bidirectional TVS tube D3;

[0094] The second end of the voltage-dividing resistor R5 and the second end of the voltage-dividing resistor R6 are both connected to the second wiring terminal B.

[0095] In order to limit the current in the three-phase detection circuit and protect other components in the three-phase detection circuit from damage by overcurrent, refer to the attached Figure 3 The three-phase detection circuit of this embodiment further provides a current limiting resistor R4, a first end of the current limiting resistor R4 is connected to the second end of the inductor T1, and a second end of the current limiting resistor R4 is connected to the third terminal C.

[0096] Example 2

[0097] Based on the same inventive concept, the present invention also provides an air conditioner, which includes the three-phase detection circuit described above.

[0098] It should be noted that the three phases of the three-phase power supply 1 in this embodiment are all correctly connected by default, and there is no poor connection of the wiring.

[0099] Therefore, the air conditioner proposed by the present invention can individually detect whether one phase of the three-phase power supply 1 is correctly connected to the corresponding phase of the three-phase load 2, and thus detect in turn whether the three phases of the three-phase power supply 1 are correctly connected to the corresponding three phases of the three-phase load 2, thereby effectively avoiding the problems of reverse phase, phase loss or poor wiring contact of the three-phase load 2, and further avoiding the problems of reversal, heating and other problems of the three-phase load 2, preventing the three-phase load 2 from burning, and ensuring the normal operation of the air conditioner.

[0100] Among them, refer to the attached Figure 3 The three-phase detection circuit includes a current limiting resistor R1, a voltage dividing resistor R2, a voltage dividing resistor R3, a current limiting resistor R4, a voltage dividing resistor R5, a voltage dividing resistor R6, an inductor T1, a light emitting diode D1, a diode D2, a bidirectional TVS tube D3 and a PTC unit 20;

[0101] The first end of the voltage-dividing resistor R2 and the first end of the voltage-dividing resistor R3 are both connected to the first wiring terminal A, which is the power supply end; the second end of the voltage-dividing resistor R2 and the second end of the voltage-dividing resistor R3 are both connected to the first end of the inductor T1, and the inductor T1 is also coupled to a switch, and the second end of the inductor T1 is respectively connected to the positive electrode of the light-emitting diode D1, the first end of the capacitor C1, the first end of the bidirectional TVS tube D3 and the first end of the current-limiting resistor R4; the negative electrode of the light-emitting diode D1 is connected to the first end of the current-limiting resistor R1; the second end of the capacitor C1 is connected to the positive electrode of the diode D2; the second end of the current-limiting resistor R1, the negative electrode of the diode D2, the second end of the bidirectional TVS tube D3 and the second end of the current-limiting resistor R4 are all connected to the third wiring terminal C, and the third wiring terminal C is also respectively connected to the first end of the voltage-dividing resistor R5 and the first end of the voltage-dividing resistor R6, and the second end of the voltage-dividing resistor R5 and the second end of the voltage-dividing resistor R6 are both connected to the second wiring terminal B, and the second wiring terminal B is the driving end.

[0102] In this way, the three-phase detection circuit in this embodiment uses fewer components and has lower cost, and can also independently detect whether one phase of the three-phase power supply 1 is correctly connected to the corresponding phase of the three-phase load 2, effectively avoiding the problems of reverse phase, phase loss or poor wiring contact of the three-phase load 2, thereby avoiding the problems of reversal and heating of the three-phase load 2, preventing the three-phase load 2 from burning, and ensuring the normal operation of the air conditioner.

[0103] Example 3

[0104] Based on the same inventive concept, refer to the attached Figure 4 The present invention also proposes a detection method using the above-mentioned three-phase detection circuit, the three-phase detection circuit includes a power supply end connected to one phase of the three-phase power supply 1, and a driving end connected to the corresponding phase of the three-phase load 2; the detection method includes:

[0105] The voltage difference between the power supply end and the drive end is obtained, the voltage difference is compared with a preset voltage, and whether the wiring of the corresponding phase of the three-phase load 2 is correct is determined separately according to the comparison result.

[0106] It should be noted that the three phases of the three-phase power supply 1 in this embodiment are all correctly connected by default, and there is no poor connection of the wiring.

[0107] Therefore, the detection method proposed in the present invention can individually detect whether one phase of the three-phase power supply 1 is correctly connected to the corresponding phase of the three-phase load 2, so as to detect in turn whether the three phases of the three-phase power supply 1 are correctly connected to the corresponding three phases of the three-phase load 2, effectively avoiding the problems of reverse phase, phase loss or poor wiring contact of the three-phase load 2, and further avoiding the problems of reversal, heating and the like of the three-phase load 2, preventing the three-phase load 2 from burning, and ensuring the normal operation of the three-phase load 2.

[0108] Further, according to the comparison result, it is determined whether the connection of the corresponding phase of the three-phase load 2 is correct. The detection method includes:

[0109] If the voltage difference is zero, neither the PTC unit 20 nor the warning unit 40 is activated, and the wiring of the corresponding phase of the three-phase load 2 is correct;

[0110] If the voltage difference is the maximum preset voltage, the PTC unit 20 is activated, the warning unit 40 is not activated, and the connection of the corresponding phase of the three-phase load 2 is missing or reversed.

[0111] It should be noted that the maximum preset voltage in this embodiment is preferably ±380V. Of course, the maximum preset voltage can also be selected as other values ​​according to actual conditions, which is not limited here.

[0112] Specifically, when the power supply end is connected to one phase of the three-phase power supply 1 and the drive end is correctly connected to the corresponding phase of the three-phase load 2, the phase and voltage of the power supply end and the drive end in the three-phase detection circuit will be the same, so that no current will flow through the entire three-phase detection circuit.

[0113] When the power supply end is connected to one phase of the three-phase power supply 1 and the driving end is connected to the corresponding phase of the three-phase load 2 and a phase loss or reverse phase occurs, there will be an alternating voltage difference of ±380V between the power supply end and the driving end in the three-phase detection circuit, which will cause a current of more than 50mA to flow through the three-phase detection circuit, causing the switch unit 30 to be disconnected to cut off the power to the three-phase load 2. However, at this time, current still flows through the PTC unit 20, causing the temperature of the circuit where the PTC unit 20 is located to rise, and the PTC unit 20 heats up, causing the temperature of the PTC unit 20 to exceed its preset safety threshold and enter a protection state, so as to achieve circuit protection for the entire three-phase detection circuit.

[0114] Further, according to the comparison result, it is determined whether the connection of the corresponding phase of the three-phase load 2 is correct. The detection method includes:

[0115] Determine whether the voltage difference is greater than a first preset voltage and whether the duration reaches a preset time;

[0116] If not, the warning unit 40 is not activated, and the wiring of the corresponding phase of the three-phase load 2 is correct;

[0117] If so, the warning unit 40 is activated, and the connection of the corresponding phase of the three-phase load 2 has poor contact.

[0118] It should be noted that, in the present embodiment, the first preset voltage is preferably 50V, and the preset time is preferably 0.5 seconds. Of course, the first preset voltage and the preset time can also be selected as other values ​​according to actual conditions, which are not limited here.

[0119] Sometimes, the three-phase detection circuit may experience instantaneous high-voltage interference, which may cause the voltage difference to be greater than the first preset voltage. However, this interference will be quickly absorbed by the capacitor C1, that is, the duration of the voltage difference being greater than the first preset voltage does not reach the preset time. Therefore, the light-emitting diode D1 will not be lit, and the three-phase detection circuit will remain in a power-off state.

[0120] Therefore, when the power supply end is connected to one phase of the three-phase power supply 1, the driving end is correctly connected to the corresponding phase of the three-phase load 2, but the three-phase load 2 has poor wiring contact, then there will be a certain alternating voltage difference between the power supply end and the driving end in the three-phase detection circuit, so the PTC unit 20 is started at this time, but its temperature will not exceed its preset safety threshold, that is, the PTC unit 20 will not enter the protection state. When the voltage difference is not greater than the first preset voltage or the voltage difference is greater than the first preset voltage but the duration does not reach the preset time, it indicates that the voltage difference at this time is an error within the acceptable range, that is, the three-phase load 2 does not have a problem of poor wiring contact; when the voltage difference is greater than the first preset voltage, the voltage difference will charge the capacitor C1 in the energy storage filter unit 50, and if the charging time of the capacitor C1 (the charging time in this embodiment is equivalent to the duration) reaches the preset time, the capacitor C1 will be fully charged and power will be supplied to the warning unit 40, so that the light-emitting diode D1 in the warning unit 40 lights up, reminding the user that the three-phase load 2 has poor wiring contact, so as to promptly notify the maintenance personnel to check the wiring condition to improve the user's experience.

[0121] Obviously, the embodiments described above are only some embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific embodiments, or to perform equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of the present invention, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A three-phase detection circuit, comprising a power supply terminal for connecting one phase of a three-phase power supply (1) and a drive terminal for connecting a corresponding phase of a three-phase load (2), characterized in that: The three-phase detection circuit also includes a first voltage dividing unit (10), a switch unit (30), a warning unit (40) and an energy storage filter unit (50); The input end of the first voltage dividing unit (10) is connected to a first wiring terminal, and the first wiring terminal is the power supply end; The output end of the first voltage dividing unit (10) is connected to the input end of the switch unit (30), the output end of the switch unit (30) is respectively connected to the input end of the warning unit (40) and the input end of the energy storage filter unit (50), the output end of the warning unit (40) and the output end of the energy storage filter unit (50) are both connected to a second wiring terminal, and the second wiring terminal is the driving end.

2. The three-phase detection circuit according to claim 1, characterized in that: The three-phase detection circuit also includes a PTC unit (20) arranged between the first connection terminal and the second connection terminal.

3. The three-phase detection circuit according to claim 1, characterized in that: The switch unit (30) comprises an inductor L1 and a switch coupled to the inductor; The first end of the inductor L1 is connected to the input end of the first voltage divider unit (10), and the second end of the inductor L1 is respectively connected to the input end of the warning unit (40) and the input end of the energy storage filter unit (50).

4. The three-phase detection circuit according to claim 1, characterized in that: The warning unit (40) comprises a light emitting diode D1 and a current limiting resistor R1; The positive electrode of the light-emitting diode D1 is connected to the output end of the switch unit (30), the negative electrode of the light-emitting diode D1 is connected to the first end of the current-limiting resistor R1, and the second end of the current-limiting resistor R1 is connected to a second wiring terminal.

5. The three-phase detection circuit according to claim 1, characterized in that: The energy storage filter unit (50) comprises a capacitor C1 and a diode D2; The first end of the capacitor C1 is connected to the output end of the switch unit (30), the second end of the capacitor C1 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to a second wiring terminal.

6. The three-phase detection circuit according to claim 1, characterized in that: The first voltage dividing unit (10) comprises a voltage dividing resistor R2 and a voltage dividing resistor R3 which are arranged in parallel; The first end of the voltage-dividing resistor R2 and the first end of the voltage-dividing resistor R3 are both connected to a first wiring terminal, and the second end of the voltage-dividing resistor R2 and the second end of the voltage-dividing resistor R3 are both connected to the input end of the switch unit (30).

7. The three-phase detection circuit according to claim 1, characterized in that: The three-phase detection circuit further comprises a protection unit (60), wherein the protection unit (60) comprises a bidirectional TVS tube D3; The output end of the switch unit (30) is connected to the first end of the bidirectional TVS tube D3, and the second end of the bidirectional TVS tube D3 is connected to a second wiring terminal.

8. The three-phase detection circuit according to claim 1, characterized in that: The three-phase detection circuit further comprises a second voltage dividing unit (70), wherein the second voltage dividing unit (70) comprises a voltage dividing resistor R5 and a voltage dividing resistor R6; The first end of the voltage-dividing resistor R5 and the first end of the voltage-dividing resistor R6 are both connected to a third wiring terminal, and the third wiring terminal is also respectively connected to the output end of the warning unit (40) and the output end of the energy storage filter unit (50); the second end of the voltage-dividing resistor R5 and the second end of the voltage-dividing resistor R6 are both connected to the second wiring terminal.

9. The three-phase detection circuit according to claim 8, characterized in that: A current limiting resistor R4 is also connected between the output end of the switch unit (30) and the third wiring terminal.

10. An air conditioner, characterized in that The air conditioner comprises the three-phase detection circuit according to any one of claims 1-9.

11. A detection method using a three-phase detection circuit as claimed in any one of claims 1 to 9, wherein the three-phase detection circuit comprises a power supply end connected to one phase of a three-phase power supply (1), and a drive end connected to a corresponding phase of a three-phase load (2); characterized in that: The detection method comprises: The voltage difference between the power supply end and the drive end is obtained, the voltage difference is compared with a preset voltage, and whether the wiring of the corresponding phase of the three-phase load (2) is correct is determined separately according to the comparison result.

12. The detection method according to claim 11, characterized in that: According to the comparison result, it is determined whether the connection of the corresponding phase of the three-phase load (2) is correct. The detection method comprises: If the voltage difference is zero, the PTC unit (20) is not activated, and the connection of the corresponding phase of the three-phase load (2) is correct; If the voltage difference is the maximum preset voltage, the PTC unit (20) is activated, and the connection of the corresponding phase of the three-phase load (2) is phase-lost or phase-reversed.

13. The detection method according to claim 11, characterized in that: According to the comparison result, it is determined whether the connection of the corresponding phase of the three-phase load (2) is correct. The detection method comprises: Determine whether the voltage difference is greater than a first preset voltage and whether the duration reaches a preset time; If not, the warning unit (40) is not activated, and the wiring of the corresponding phase of the three-phase load (2) is correct; If so, the warning unit (40) is activated, and the wiring contact of the corresponding phase of the three-phase load (2) is poor.

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