Three-phase power input protection circuit and air conditioner

Abstract

The utility model discloses a three-phase power input protection circuit and an air conditioner wherein the three-phase power input protection circuit comprises a voltage conversion circuit, a plurality of input ends of which are used for accessing each phase voltage waveform of three-phase power in a one-to-one correspondence manner; a plurality of input ends of the first AND gate are used for being connected with a plurality of output ends of the voltage conversion circuit in a one-to-one correspondence manner; a first input end of the trigger circuit is used for accessing a first reference voltage, a clock end of the trigger circuit is used for accessing a first square wave signal, an output end of the trigger circuit is used for accessing a power supply management circuit, and the trigger circuit is used for not detecting that the first AND gate outputs a high level when triggered by a rising edge of the first square wave signal; and the power supply management circuit is controlled to disconnect the external load from the three-phase power. The technical scheme of the utility model aims to detect the three-phase alternating current before the air conditioner is started to work.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, in particular to a three-phase electric input protection circuit and an air conditioner. Background Art

[0002] At present, the common power source for high-power air conditioners is three-phase AC, which provides energy for the operation of air conditioners and plays an extremely important role in the operation of air conditioners. Since the input power supply of some air conditioner circuit boards does not allow the phase sequence to be reversed, once the phase sequence is reversed, the air conditioner will not work properly. Therefore, how to detect the three-phase AC before the air conditioner starts working has become an urgent problem to be solved. Utility Model Content

[0003] The main purpose of the utility model is to provide a three-phase electric input protection circuit and an air conditioner, aiming at detecting the three-phase alternating current before the air conditioner starts working.

[0004] To achieve the above-mentioned purpose, the three-phase power input protection circuit proposed in the utility model is applied to an air conditioner, wherein the air conditioner includes a functional load and a power supply management circuit electrically connected to each other, wherein the power supply management circuit is used to access the three-phase power, and the three-phase power input protection circuit includes:

[0005] A voltage conversion circuit, wherein the plurality of input terminals are used to be connected to the voltage waveforms of each phase of the three-phase electricity in a one-to-one correspondence, and the voltage conversion circuit is used to convert the voltage waveforms of each phase respectively and output a corresponding first square wave signal, a second square wave signal and a third square wave signal;

[0006] A first AND gate, wherein the plurality of input terminals are connected to the plurality of output terminals of the voltage conversion circuit in a one-to-one correspondence, and the first AND gate is used to output a high level when the first square wave signal, the second square wave signal and the third square wave signal connected thereto are all at a first level;

[0007] A trigger circuit, wherein the first input terminal is used to access the first reference voltage, the clock terminal is used to access the first square wave signal, and the output terminal is used to access the power supply management circuit. The trigger circuit is used to control the power supply management circuit to keep the functional load disconnected from the three-phase power when the trigger circuit is triggered by the rising edge of the first square wave signal and fails to detect that the first AND gate outputs a high level.

[0008] In some embodiments, the voltage waveform includes a first voltage waveform, a second voltage waveform, and a third voltage waveform, and the voltage conversion circuit includes:

[0009] A plurality of first voltage conversion branches are connected to the first voltage waveform and the third voltage waveform in a one-to-one correspondence, and are used to output a corresponding first square wave signal after rectifying and converting the first voltage waveform, and to output a corresponding third square wave signal after rectifying and converting the third voltage waveform;

[0010] The second voltage conversion branch has an input end for receiving the second voltage waveform, for rectifying and converting the second voltage waveform, and then inverting it, and outputting a corresponding inverted square wave as a second square wave signal.

[0011] In some embodiments, the first voltage conversion branch or the second voltage conversion branch includes:

[0012] A first comparator has a first non-inverting input terminal, a first inverting input terminal, a first power supply terminal and a first ground terminal, wherein the first power supply terminal is used to connect to a first power supply, and the first inverting input terminal and the first ground terminal are grounded respectively;

[0013] A first triode having a first base, a first collector and a first emitter;

[0014] A first diode, wherein an anode of the first diode is used to access the voltage waveform;

[0015] a first resistor and a second resistor, wherein the first resistor is connected in series between the cathode of the first diode and the positive phase input terminal, a first end of the second resistor is connected to the first positive phase input terminal, and a second end of the second resistor is used to access a neutral line;

[0016] a third resistor and a fourth resistor, wherein the third resistor is connected in series between the output terminal of the comparator and the first base, and the fourth resistor is connected in series between the first base and ground;

[0017] a fifth resistor, wherein a first end of the fifth resistor is used to connect to a second power supply, and a second end of the fifth resistor is connected to the first collector.

[0018] A sixth resistor, connected in series between the first emitter and ground;

[0019] The first capacitor is connected in parallel to both ends of the sixth resistor.

[0020] In some embodiments, in the second voltage conversion branch, the emitter of the transistor is the output end of the second voltage conversion branch, and the second voltage conversion branch further includes:

[0021] The second capacitor is connected in parallel with the collector of the transistor and the emitter of the transistor.

[0022] In some embodiments, the three-phase electrical input protection circuit further includes:

[0023] At least one undervoltage detection circuit, wherein two input terminals of the undervoltage detection circuit are respectively used to access any two phases of the three-phase electricity, and a reference terminal of the undervoltage detection circuit is used to access a second reference voltage, and the undervoltage detection circuit is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is less than the second reference voltage;

[0024] At least one overvoltage detection circuit, wherein the two input terminals of the overvoltage detection circuit are respectively used to access any two phases of the three-phase electricity, the reference terminal of the overvoltage detection circuit is used to access a third reference voltage, the overvoltage detection circuit is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is greater than the third reference voltage; wherein the third reference voltage is greater than the second reference voltage;

[0025] A second AND gate, wherein a plurality of input terminals of the second AND gate are respectively connected to an output terminal of at least one of the overvoltage detection circuits and an output terminal of at least one of the overvoltage detection circuits, and the second AND gate is used to output a corresponding clearing signal when detecting that any low level is connected;

[0026] The trigger circuit also has a reset terminal, which is connected to the output terminal of the second AND gate. The trigger circuit is also used to control the power supply management circuit to keep the functional load disconnected from the three-phase power when receiving the reset signal.

[0027] In some embodiments, the undervoltage detection circuit includes:

[0028] The Hall sensor comprises a first collecting terminal, a second collecting terminal, an output terminal and a grounding terminal, wherein the second collecting terminal is used to access any one phase of the three-phase electricity, and the grounding terminal is grounded;

[0029] A second comparator has a second non-inverting input terminal, a second inverting input terminal, a second power supply terminal and a second ground terminal, wherein the second power supply terminal is used to connect to a third power supply, the second inverting input terminal is used to connect to the second reference voltage, and the second ground terminal is grounded;

[0030] a seventh resistor, wherein a first end of the seventh resistor is used to connect to any remaining phase of the three-phase electricity, and a second end of the seventh resistor is connected to the first acquisition end;

[0031] An eighth resistor is connected in series between the output terminal of the Hall sensor and the second non-inverting input terminal;

[0032] a ninth resistor connected in series between the output terminal of the second comparator and the second AND gate;

[0033] A third capacitor is connected in series between the second non-inverting input terminal and ground;

[0034] The clamping tube is connected in series between the input terminal of the second AND gate and the ground.

[0035] In some embodiments, the trigger circuit includes:

[0036] A first trigger, comprising a first input pin, a first clock pin, a first clear pin and a first output pin, wherein the first input pin is a first input end of the trigger circuit, the first clock pin is a clock end of the trigger circuit, and the first clear pin is used to access a third wave signal;

[0037] A second trigger, comprising a second input pin, a second clock pin, a second clear pin and a second output pin, wherein the second input pin is a second input end of the trigger circuit, the second clock pin is connected to the first output pin, the second clear pin is a clear end of the trigger circuit, and the second output pin is an output end of the trigger circuit;

[0038] The first trigger is used to output a corresponding trigger signal when receiving a rising edge of the first square wave signal, and to clear the trigger signal when the connected third square wave signal is at a low level;

[0039] The second trigger is used to control the power supply management circuit to disconnect the functional load from the three-phase power when the trigger signal is received and the first AND gate is not detected to output a high level.

[0040] In some embodiments, the three-phase electrical input protection circuit further includes:

[0041] A power supply circuit, wherein the two input ends of the power supply circuit are used to access the neutral line and any one phase of the three-phase electricity, and the output end of the power supply circuit is electrically connected to the voltage conversion circuit, the first AND gate, and the trigger circuit, respectively, and is used to rectify the connected one-phase voltage and then perform voltage transformation to power the voltage conversion circuit, the first AND gate, and the trigger circuit.

[0042] The utility model also provides an air conditioner, which includes at least one load, a power supply management circuit and the above-mentioned three-phase power input protection circuit.

[0043] In some embodiments, the power management circuit includes:

[0044] A relay comprises a coil and a plurality of contacts, wherein the first ends of the plurality of contacts are used to be connected to three-phase electricity in a one-to-one correspondence, the second ends of the plurality of contacts are used to be connected to the multi-phase input end of the load in a one-to-one correspondence, and the first end of the coil is used to be connected to a first power supply

[0045] a second diode connected in parallel to both ends of the coil;

[0046] A second triode, comprising a second base, a second collector and a second emitter, wherein the second collector is connected to the second end of the coil, and the second base is connected to the output end of the three-phase power input protection circuit;

[0047] A fourth capacitor is connected in series between the second base and the ground;

[0048] The tenth resistor is connected in series between the second emitter and the ground.

[0049] The technical solution of the utility model converts the waveform of the input three-phase electricity into a square wave signal that can be recognized by the trigger circuit by setting a voltage conversion circuit, and uses the relationship between the waveforms of the AC voltages of each phase to set the trigger circuit to be triggered by the rising edge of the first square wave signal, and the trigger signal is cleared by the falling edge of the third square wave signal, so that the time period when the trigger circuit is triggered is fixed between the rising edge of the first square wave signal and the falling edge of the third square wave signal, and the output level of the first AND gate in this time period is detected. When the first AND gate does not output the first level, it is detected that the phase sequence of the input three-phase electricity is wrong, and the external load is disconnected from the three-phase electricity. Therefore, before the air conditioner starts working, the three-phase electricity is detected to avoid the situation where the air conditioner cannot work normally due to the reverse phase sequence of the three-phase electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0051] Figure 1 This is a schematic diagram of the structure of an embodiment of a three-phase power input protection circuit of the utility model;

[0052] Figure 2 It is a structural schematic diagram of another embodiment of the three-phase power input protection circuit of the utility model;

[0053] Figure 3 It is a structural schematic diagram of another embodiment of the three-phase power input protection circuit of the utility model;

[0054] Figure 4 This is a circuit connection diagram of an embodiment of a voltage conversion circuit of the utility model;

[0055] Figure 5 A circuit connection diagram of an embodiment of an undervoltage detection circuit of the utility model;

[0056] Figure 6 A circuit connection diagram of an embodiment of a trigger circuit of the utility model;

[0057] Figure 7 It is the voltage waveform diagram of three-phase electricity;

[0058] Figure 8 This is a square wave signal diagram of the three-phase voltage waveform after processing.

[0059] Description of Figure Numbers:

[0060]

[0061]

[0062] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0064] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0065] The utility model provides a three-phase power input protection circuit, which is applied to an air conditioner. The air conditioner comprises a functional load and a power supply management circuit which are electrically connected to each other. The power supply management circuit is used for accessing the three-phase power.

[0066] Reference Figure 1 In one embodiment, the three-phase electrical input protection circuit comprises:

[0067] The voltage conversion circuit 100 has multiple input terminals for correspondingly accessing the voltage waveforms of each phase of the three-phase power, and the voltage conversion circuit 100 is used to convert the voltage waveforms of each phase respectively and output the corresponding first square wave signal, second square wave signal and third square wave signal;

[0068] A first AND gate 200, wherein the plurality of input terminals are connected to the plurality of output terminals of the voltage conversion circuit 100 in a one-to-one correspondence, and the first AND gate 200 is used to output a high level when the first square wave signal, the second square wave signal, and the third square wave signal connected thereto are all at the first level;

[0069] The trigger circuit 300 has a first input terminal for accessing a first reference voltage, a clock terminal for accessing a first square wave signal, and an output terminal for accessing a power supply management circuit. When the trigger circuit 300 is triggered by the rising edge of the first square wave signal and fails to detect that the first AND gate 200 outputs a high level, the power supply management circuit is controlled to keep the functional load disconnected from the three-phase power.

[0070] It is important to understand that Figure 7 As shown, under normal phase sequence, the voltage waveforms of the first phase, second phase, and third phase of the three-phase electricity should be 120 degrees apart in phase. On this basis, in the current cycle, when the voltage waveform of the first phase gradually increases positively from 0, it overlaps with the voltage waveform of the third phase of the previous cycle before it drops to 0. If the voltage waveform of the second phase is inverted, then when the voltage waveform of the first phase increases positively from 0, and before the voltage waveform of the third phase drops to 0, the voltage waveforms of the three-phase electricity should all be positive.

[0071] In this embodiment, a voltage conversion circuit 100 is provided. The multiple input terminals of the voltage conversion circuit 100 include a first phase input terminal, a second phase input terminal and a third phase input terminal. When the phase sequence is normal, the first phase input terminal should be connected to the first phase alternating current R, the second phase input terminal should be connected to the second phase alternating current S, and the third phase input terminal should be connected to the third phase alternating current T. The voltage conversion circuit 100 converts the waveforms of the voltages of each phase connected, converts the part with a voltage greater than 0 to a high level, and converts the part with a voltage less than 0 to a low level, and obtains the following: Figure 8 The square wave signal shown, according to the above principle, after the waveform connected to the second phase input terminal is inverted, between the rising edge of the first square wave signal and the falling edge of the second square wave signal, the three square wave models should all be at a high level, so that the connected first AND gate 200 maintains the output of the first level during this period.

[0072] This embodiment is also provided with a trigger circuit 300, the clock pin of the trigger circuit 300 is set to be triggered by the rising edge of the first square wave signal, and the clear pin of the trigger circuit 300 is set to be triggered by the falling edge of the third wave, so that when the trigger circuit 300 is working, it is triggered after receiving the rising edge of the first square wave signal, and is cleared after receiving the falling edge of the third wave signal, and the continuously received first reference voltage is processed into a clock signal with the clock period of the first square wave signal as a period, which is a high level at the rising edge of the first square wave signal and the falling edge of the third wave signal, and a low level after the falling edge of the third wave signal, and the output of the first AND gate 200 is detected by the clock signal. When the clock signal is at a high level, the first AND gate 200 can output the first level, which means that the phase sequence of the three-phase electricity input at this time is correct, and when the clock signal is at a high level, the first AND gate 200 does not output the first level, which means that the phase sequence of the three-phase electricity input at this time is incorrect.

[0073] It can be understood that in the air conditioner, a power supply management circuit is arranged between each functional load and the three-phase electricity. When the trigger circuit 300 detects that the phase sequence of the three-phase electricity is incorrect, it will drive the power supply management circuit to keep each functional load disconnected from the three-phase electricity. When the phase sequence of the three-phase electricity is detected to be correct, the trigger circuit 300 will drive the power supply management circuit to connect each functional load to the three-phase electricity respectively, so that the three-phase electricity can power each functional load.

[0074] The technical solution of the utility model converts the voltage waveform of the input three-phase electricity into a square wave signal that can be recognized by the trigger circuit 300 by setting a voltage conversion circuit 100, and uses the relationship between the voltage waveforms of each phase to set the trigger circuit 300 to be triggered by the rising edge of the first square wave signal, and the trigger signal is cleared by the falling edge of the third square wave signal, so that the time period when the trigger circuit 300 is triggered is fixed between the rising edge of the first square wave signal and the falling edge of the third square wave signal, and the output level of the first AND gate 200 in this time period is detected. When the first AND gate 200 does not output the first level, it is detected that the phase sequence of the input three-phase electricity is wrong, and the external load is disconnected from the three-phase electricity. Therefore, before the air conditioner starts working, the three-phase electricity is detected to avoid the situation where the air conditioner cannot work normally due to the reverse phase sequence of the three-phase electricity.

[0075] Reference Figure 2 In one embodiment, the voltage waveform includes a first voltage waveform, a second voltage waveform and a third voltage waveform, and the voltage conversion circuit 100 includes:

[0076] A plurality of first voltage conversion branches 110 are connected to the first voltage waveform and the third voltage waveform in a one-to-one correspondence, and are used to output a corresponding first square wave signal after rectifying and converting the first voltage waveform, and to output a corresponding third square wave signal after rectifying and converting the third voltage waveform;

[0077] The second voltage conversion branch 120 has an input end for receiving the second voltage waveform, for rectifying and converting the second voltage waveform, and then inverting it, and outputting a corresponding inverted square wave as a second square wave signal.

[0078] In this embodiment, the first voltage conversion branch 110 is used to convert the connected two-phase voltage waveform, convert the part where the voltage is greater than 0 to a high level, and convert the part where the voltage is less than 0 to a low level, so as to obtain Figure 8 The first square wave signal A and the third square wave signal C shown in FIG. 1 are used for converting the input one-phase voltage waveform and then performing inversion processing to obtain the following: Figure 8 The second square wave signal B is shown.

[0079] Reference Figure 2 and Figure 4 In one embodiment, the first voltage conversion branch 110 or the second voltage conversion branch 120 includes:

[0080] The first comparator U1 has a first positive input terminal, a first negative input terminal, a first power supply terminal and a first ground terminal, the first power supply terminal is used to connect to the first power supply, the first negative input terminal and the first ground terminal are grounded respectively;

[0081] The first transistor Q1 has a first base, a first collector and a first emitter;

[0082] A first diode D1, an anode of the first diode D1 is used to access a voltage waveform;

[0083] A first resistor R1 and a second resistor R2, wherein the first resistor R1 is connected in series between the cathode of the first diode D1 and the positive phase input terminal, a first end of the second resistor R2 is connected to the first positive phase input terminal, and a second end of the second resistor R2 is used to access the neutral line;

[0084] a third resistor R3 and a fourth resistor R4, wherein the third resistor R3 is connected in series between the output terminal of the comparator and the first base, and the fourth resistor R4 is connected in series between the first base and the ground;

[0085] a fifth resistor R5, wherein a first end of the fifth resistor R5 is used to connect to the second power supply, and a second end of the fifth resistor R5 is connected to the first collector.

[0086] A sixth resistor R6 is connected in series between the first emitter and the ground;

[0087] The first capacitor is connected in parallel to both ends of the sixth resistor R6.

[0088] In this embodiment, when the first voltage conversion branch 110 or the second voltage conversion branch 120 is connected to the corresponding one-phase voltage waveform, the voltage waveform is half-wave rectified by using the unidirectional conduction principle of the diode, and the positive half-wave is output and the negative half-wave is stopped from being output, so that the output half-wave waveform can be recognized by the first comparator U1. The first inverting input terminal of the first comparator U1 is grounded, that is, when the voltage connected to the first positive input terminal is higher than 0, the first comparator U1 outputs a high level and drives the first transistor Q1 to turn on. When the voltage connected to the first positive input terminal is not higher than 0, the first comparator U1 outputs a low level and drives the first transistor Q1 to turn off, so that the corresponding square wave signal can be output.

[0089] Furthermore, in the second voltage conversion branch 120, the emitter of the transistor is the output end of the second voltage conversion branch 120, and the second voltage conversion branch 120 further includes:

[0090] The second capacitor C2 is connected in parallel with the collector of the transistor and the emitter of the transistor.

[0091] In this embodiment, in the first voltage conversion branch 110, the first emitter is the output terminal, and a square wave signal with a consistent waveform is output according to the connected driving signal. In the second voltage conversion branch 120, the first collector is the output terminal. When the first transistor Q1 is turned on, the voltage of the first collector is pulled down to the ground, and when the first transistor Q1 is turned off, the voltage of the first collector is pulled up to the voltage of the second power supply.

[0092] It should be noted that the air conditioner's detection of three-phase AC power also includes amplitude detection. Under normal circumstances, the amplitude of the line voltage is 380V, but as the grid voltage fluctuates, the line voltage may be too low or too high. For example, when other high-power devices are running in an area, the grid voltage will be greatly lowered. At this time, starting the air conditioner powered by three-phase electricity will cause the transformer to trip, damage electrical equipment, and further increase the line voltage. Excessive line voltage will directly damage the air conditioner and pose a safety hazard to the user. Too low or too high line voltage will also cause a series of hazards.

[0093] Therefore, refer to Figure 3 In one embodiment, the three-phase electrical input protection circuit further includes:

[0094] At least one undervoltage detection circuit 410, wherein two input terminals of the undervoltage detection circuit 410 are respectively used to access any two phases of the three-phase electricity, and a reference terminal of the undervoltage detection circuit 410 is used to access a second reference voltage. The undervoltage detection circuit 410 is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is less than the second reference voltage;

[0095] At least one overvoltage detection circuit 420, two input terminals of the overvoltage detection circuit 420 are respectively used to access any two phases of the three-phase electricity, and the reference terminal of the overvoltage detection circuit 420 is used to access a third reference voltage. The overvoltage detection circuit 420 is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is greater than the third reference voltage; wherein the third reference voltage is greater than the second reference voltage;

[0096] A second AND gate 500, wherein a plurality of input terminals of the second AND gate 500 are respectively connected to an output terminal of at least one overvoltage detection circuit 420 and an output terminal of at least one overvoltage detection circuit 420, and the second AND gate 500 is used to output a corresponding clearing signal when detecting that any low level is connected;

[0097] The trigger circuit 300 also has a reset terminal connected to the output terminal of the second AND gate 500. The trigger circuit 300 is also used to control the power supply management circuit to disconnect the functional load from the three-phase power when receiving a reset signal.

[0098] In this embodiment, when the voltage of the three-phase electricity connected to the air conditioner is too high, the line voltage collected by the overvoltage detection circuit 420 is greater than the third reference voltage, so that the overvoltage detection circuit 420 outputs a low level. Similarly, when the voltage of the three-phase electricity connected to the air conditioner is too low, the line voltage collected by the undervoltage detection circuit 410 is less than the second reference voltage, so that the undervoltage detection circuit 410 outputs a low level. When the second AND gate 500 receives any low level, it also outputs a low level, that is, a reset signal. The low level is output to the reset end of the trigger circuit 300, that is, the second reset pin of the second trigger 320, and the output end of the second trigger 320 is reset to zero, and a low level is output, which cannot drive the power supply management circuit to connect each functional load to the three-phase electricity.

[0099] When the phase voltage of the input three-phase electricity is within the range of 165V to 265V, both the overvoltage detection circuit 420 and the undervoltage detection circuit 410 output a high level. The low level is sent to the reset terminal of the trigger circuit 300, that is, the second reset pin of the second trigger 320. Since the trigger terminal of the trigger circuit 300 is low level effective (that is, the low level makes the second output terminal of the second trigger 320 "clear"), the high level is invalid (that is, the high level has no effect on the second output terminal of the second trigger 320). At this time, the level of the second output terminal of the second trigger 320 depends on the second input terminal of the second trigger 320, that is, depends on the phase sequence of the input three-phase electricity.

[0100] Combining the phase sequence detection function and the amplitude detection function of the three-phase power input protection circuit, the amplitude detection function has a higher priority. However, only when the phase sequence of the input three-phase power is positive and the amplitude of the input three-phase power is in the range of 165V to 265V, the second output terminal of the second trigger 320 outputs a high level, driving the three-power supply management circuit to connect the external load to the three-phase power, thereby achieving the purpose of protecting the back-end circuit.

[0101] Reference Figure 3 and Figure 5 In one embodiment, the undervoltage detection circuit 410 includes:

[0102] The Hall sensor P1 has a first collecting terminal, a second collecting terminal, an output terminal and a grounding terminal, wherein the second collecting terminal is used to connect to any one phase of the three-phase power, and the grounding terminal is grounded;

[0103] The second comparator U2 has a second positive input terminal, a second negative input terminal, a second power supply terminal and a second ground terminal, the second power supply terminal is used to connect to the third power supply, the second negative input terminal is used to connect to the second reference voltage, and the second ground terminal is grounded;

[0104] A seventh resistor R7, wherein a first end of the seventh resistor R7 is used to connect to any remaining phase of the three-phase electricity, and a second end of the seventh resistor R7 is connected to the first collection end;

[0105] An eighth resistor R8 is connected in series between the output terminal of the Hall sensor P1 and the second non-inverting input terminal;

[0106] A ninth resistor R9 is connected in series between the output terminal of the second comparator U2 and the second AND gate 500;

[0107] A third capacitor C3 is connected in series between the second non-inverting input terminal and the ground;

[0108] The clamping tube TZ1 is connected in series between the input terminal of the second AND gate 500 and the ground.

[0109] In this embodiment, the Hall sensor P1 is used to collect the line voltage between any two phases of the three-phase electricity, and output the voltage sampling signal of the corresponding voltage value to the positive input terminal of the second comparator U2. The negative input terminal of the second comparator U2 is connected to the second reference voltage. The second reference voltage is set by the R&D personnel according to the voltage value of the voltage sampling signal corresponding to the undervoltage critical value of the line voltage. When the undervoltage critical value is 165V and the voltage value of the corresponding voltage sampling signal is 2V, the second reference voltage is 2V. Similarly, in the overvoltage detection circuit 420, the third reference voltage is set by the R&D personnel according to the voltage value of the voltage sampling signal corresponding to the overvoltage critical value of the line voltage. When the overvoltage critical value is 265V and the voltage value of the corresponding voltage sampling signal is 4.7V, the third reference voltage is 4.7V.

[0110] The second comparator U2 compares the voltage of the voltage sampling signal with the second reference voltage. When the voltage of the voltage sampling signal is greater than the second reference voltage, it indicates that the detected line voltage is not under-voltage, thereby outputting a high level. When the voltage of the voltage sampling signal is not greater than the second reference voltage, it indicates that the detected line voltage is under-voltage, thereby outputting a low level.

[0111] Reference Figures 1 to 6 In one embodiment, the trigger circuit 300 includes:

[0112] The first trigger 310 has a first input pin, a first clock pin, a first clear pin and a first output pin, wherein the first input pin is a first input terminal of the trigger circuit 300, the first clock pin is a clock terminal of the trigger circuit 300, and the first clear pin is used to access a third wave signal;

[0113] The second trigger 320 has a second input pin, a second clock pin, a first clear pin and a second output pin, the second input pin is the second input end of the trigger circuit 300, the second clock pin is connected to the first output pin, the second clear pin is the clear end of the trigger circuit 300, and the second output pin does not trigger the output end of the circuit 300;

[0114] The first trigger 310 is used to output a corresponding trigger signal when receiving the rising edge of the first square wave signal, and clear the trigger signal when the connected third square wave signal is at a low level;

[0115] The second trigger 320 is used to control the power supply management circuit to disconnect the functional load from the three-phase power when a trigger signal is received and the first AND gate is not detected to output a high level.

[0116] In this embodiment, when the trigger circuit 300 is working, the first trigger 310 is triggered after receiving the rising edge of the first square wave signal, and continuously outputs a high level according to the received first reference voltage, and clears the output high level after receiving the falling edge of the third wave signal. The clock period of the first square wave signal is used as the period, and the rising edge of the first square wave signal and the falling edge of the third wave signal are high level, and the trigger signal is output before the falling edge of the third wave signal. The second trigger 320 is triggered when receiving the trigger signal, and the output of the first AND gate 200 is detected. When it is detected that the first AND gate 200 can output the first level, it means that the input three-phase electrical phase sequence is correct at this time, and when it is detected that the first AND gate 200 does not output the first level, it means that the input three-phase electrical phase sequence is incorrect at this time.

[0117] Reference Figure 5 In one embodiment, the three-phase electrical input protection circuit further includes:

[0118] The power supply circuit 600 has two input terminals for accessing a neutral line and any one phase of three-phase electricity. The output terminal of the power supply circuit 600 is electrically connected to the voltage conversion circuit 100, the first AND gate 200, and the trigger circuit 300, respectively, and is used to rectify and transform the voltage of one phase of the three-phase electricity to supply power to the voltage conversion circuit 100, the first AND gate 200, and the trigger circuit 300.

[0119] In this embodiment, the power supply circuit 600 includes a full-bridge rectifier circuit and a switching power supply, and the switching power supply is electrically connected to the output end of the full-bridge rectifier circuit. When the air conditioner is connected to three-phase electricity, the two input ends of the full-bridge rectifier circuit are respectively connected to any one-phase live wire and neutral wire to connect one-phase AC power, and perform full-wave rectification on it to output the corresponding DC voltage. The switching power supply performs multiple voltage conversion processes on the DC voltage, and outputs multiple DC power supplies with different voltage values ​​including the first power supply, the second power supply, and the third power supply, which supply power to the voltage conversion circuit 100, the first AND gate 200, the trigger circuit 300 and other circuits.

[0120] The utility model also proposes an air conditioner, which includes at least one load, a power supply management circuit and the above-mentioned three-phase power input protection circuit. The specific structure of the three-phase power input protection circuit refers to the above-mentioned embodiment. Since this air conditioner adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0121] Reference Figure 1 In one embodiment, the power supply management circuit includes:

[0122] The relay J1 includes a coil and a plurality of contacts, wherein the first ends of the plurality of contacts are used to be connected to the three-phase power in a one-to-one correspondence, the second ends of the plurality of contacts are used to be connected to the multi-phase input terminals of the load in a one-to-one correspondence, and the first end of the coil is used to be connected to the first power supply;

[0123] The second diode D2 is connected in parallel to both ends of the coil;

[0124] A second transistor Q2 has a second base, a second collector and a second emitter, the second collector is connected to the second end of the coil, and the second base is connected to the output end of the three-phase power input protection circuit;

[0125] A fourth capacitor C4 is connected in series between the second base and the ground;

[0126] The tenth resistor R10 is connected in series between the second emitter and the ground.

[0127] In this embodiment, when the three-phase power input protection circuit detects that the phase sequence and amplitude of the input three-phase power are normal, a high-level driving signal is output to turn on the second transistor Q2 under the high-level driving, and the first power supply forms a current loop through the relay J1, the second transistor Q2, the tenth resistor R10 and the ground, so that the relay J1 works and the contacts are attracted, as shown in FIG. Figure 5 As shown, after the corresponding contacts are all energized, the three-phase electricity RST is output to the power supply terminal UVW of the motor; when the three-phase electricity input protection circuit detects that the phase sequence of the input three-phase electricity is wrong, the line voltage is undervoltage or the line voltage is overvoltage, it outputs a low level, turning off the second transistor Q2, and the first power supply cannot form a current loop through the relay J1, so that the relay J1 stops working, the contacts are released, and the three-phase electricity RST is disconnected from the power supply terminal UVW of the motor.

[0128] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A three-phase power input protection circuit, applied to an air conditioner, the air conditioner comprising a functional load and a power supply management circuit electrically connected to each other, the power supply management circuit being used to access the three-phase power, characterized in that: The three-phase electrical input protection circuit comprises: A voltage conversion circuit, wherein the plurality of input terminals are used to be connected to the voltage waveforms of each phase of the three-phase electricity in a one-to-one correspondence, and the voltage conversion circuit is used to convert the voltage waveforms of each phase respectively and output a corresponding first square wave signal, a second square wave signal and a third square wave signal; A first AND gate, wherein the plurality of input terminals are connected to the plurality of output terminals of the voltage conversion circuit in a one-to-one correspondence, and the first AND gate is used to output a high level when the first square wave signal, the second square wave signal and the third square wave signal connected thereto are all at a first level; A trigger circuit, wherein the first input terminal is used to access the first reference voltage, the clock terminal is used to access the first square wave signal, and the output terminal is used to access the power supply management circuit. The trigger circuit is used to control the power supply management circuit to keep the functional load disconnected from the three-phase power when the trigger circuit is triggered by the rising edge of the first square wave signal and fails to detect that the first AND gate outputs a high level.

2. The three-phase power input protection circuit according to claim 1, characterized in that: The voltage waveform includes a first voltage waveform, a second voltage waveform and a third voltage waveform, and the voltage conversion circuit includes: A plurality of first voltage conversion branches are connected to the first voltage waveform and the third voltage waveform in a one-to-one correspondence, and are used to output a corresponding first square wave signal after rectifying and converting the first voltage waveform, and to output a corresponding third square wave signal after rectifying and converting the third voltage waveform; The second voltage conversion branch has an input end for receiving the second voltage waveform, for rectifying and converting the second voltage waveform, and then inverting it, and outputting a corresponding inverted square wave as a second square wave signal.

3. The three-phase power input protection circuit according to claim 2, characterized in that: The first voltage conversion branch or the second voltage conversion branch comprises: A first comparator has a first non-inverting input terminal, a first inverting input terminal, a first power supply terminal and a first ground terminal, wherein the first power supply terminal is used to connect to a first power supply, and the first inverting input terminal and the first ground terminal are grounded respectively; A first triode having a first base, a first collector and a first emitter; A first diode, wherein an anode of the first diode is used to access the voltage waveform; a first resistor and a second resistor, wherein the first resistor is connected in series between the cathode of the first diode and the positive phase input terminal, a first end of the second resistor is connected to the first positive phase input terminal, and a second end of the second resistor is used to access a neutral line; a third resistor and a fourth resistor, wherein the third resistor is connected in series between the output terminal of the comparator and the first base, and the fourth resistor is connected in series between the first base and ground; a fifth resistor, wherein a first end of the fifth resistor is used to connect to a second power supply, and a second end of the fifth resistor is connected to the first collector. A sixth resistor, connected in series between the first emitter and ground; The first capacitor is connected in parallel to both ends of the sixth resistor.

4. The three-phase power input protection circuit according to claim 3, characterized in that: In the second voltage conversion branch, the emitter of the transistor is the output end of the second voltage conversion branch, and the second voltage conversion branch further includes: The second capacitor is connected in parallel with the collector of the transistor and the emitter of the transistor.

5. The three-phase power input protection circuit according to claim 1, characterized in that: The three-phase electrical input protection circuit also includes: At least one undervoltage detection circuit, wherein two input terminals of the undervoltage detection circuit are respectively used to access any two phases of the three-phase electricity, and a reference terminal of the undervoltage detection circuit is used to access a second reference voltage, and the undervoltage detection circuit is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is less than the second reference voltage; At least one overvoltage detection circuit, wherein the two input terminals of the overvoltage detection circuit are respectively used to access any two phases of the three-phase electricity, the reference terminal of the overvoltage detection circuit is used to access a third reference voltage, the overvoltage detection circuit is used to collect the line voltage between any two phases of the three-phase electricity, and output a low level when the line voltage is greater than the third reference voltage; wherein the third reference voltage is greater than the second reference voltage; A second AND gate, wherein a plurality of input terminals of the second AND gate are respectively connected to an output terminal of at least one of the overvoltage detection circuits and an output terminal of at least one of the overvoltage detection circuits, and the second AND gate is used to output a corresponding clearing signal when detecting that any low level is connected; The trigger circuit also has a reset terminal, which is connected to the output terminal of the second AND gate. The trigger circuit is also used to control the power supply management circuit to keep the functional load disconnected from the three-phase power when receiving the reset signal.

6. The three-phase power input protection circuit according to claim 5, characterized in that: The undervoltage detection circuit comprises: The Hall sensor comprises a first collecting terminal, a second collecting terminal, an output terminal and a grounding terminal, wherein the second collecting terminal is used to access any one phase of the three-phase electricity, and the grounding terminal is grounded; A second comparator has a second non-inverting input terminal, a second inverting input terminal, a second power supply terminal and a second ground terminal, wherein the second power supply terminal is used to connect to a third power supply, the second inverting input terminal is used to connect to the second reference voltage, and the second ground terminal is grounded; a seventh resistor, wherein a first end of the seventh resistor is used to connect to any remaining phase of the three-phase electricity, and a second end of the seventh resistor is connected to the first acquisition end; An eighth resistor is connected in series between the output terminal of the Hall sensor and the second non-inverting input terminal; a ninth resistor connected in series between the output terminal of the second comparator and the second AND gate; A third capacitor is connected in series between the second non-inverting input terminal and ground; The clamping tube is connected in series between the input terminal of the second AND gate and the ground.

7. The three-phase power input protection circuit according to claim 5, characterized in that: The trigger circuit comprises: A first trigger, comprising a first input pin, a first clock pin, a first clear pin and a first output pin, wherein the first input pin is a first input end of the trigger circuit, the first clock pin is a clock end of the trigger circuit, and the first clear pin is used to access a third wave signal; A second trigger, comprising a second input pin, a second clock pin, a second clear pin and a second output pin, wherein the second input pin is a second input end of the trigger circuit, the second clock pin is connected to the first output pin, the second clear pin is a clear end of the trigger circuit, and the second output pin is an output end of the trigger circuit; The first trigger is used to output a corresponding trigger signal when receiving a rising edge of the first square wave signal, and to clear the trigger signal when the connected third square wave signal is at a low level; The second trigger is used to control the power supply management circuit to disconnect the functional load from the three-phase power when the trigger signal is received and the first AND gate is not detected to output a high level.

8. The three-phase power input protection circuit according to claim 1, characterized in that: The three-phase electrical input protection circuit also includes: A power supply circuit, wherein the two input ends of the power supply circuit are used to access the neutral line and any one phase of the three-phase electricity, and the output end of the power supply circuit is electrically connected to the voltage conversion circuit, the first AND gate, and the trigger circuit, respectively, and is used to rectify the connected one-phase voltage and then perform voltage transformation to power the voltage conversion circuit, the first AND gate, and the trigger circuit.

9. An air conditioner, characterized in that: It comprises at least one load, a power supply management circuit and a three-phase power input protection circuit as described in any one of claims 1-8.

10. The air conditioner according to claim 9, characterized in that: The power supply management circuit comprises: A relay comprises a coil and a plurality of contacts, wherein the first ends of the plurality of contacts are used to be connected to three-phase electricity in a one-to-one correspondence, the second ends of the plurality of contacts are used to be connected to the multi-phase input end of the load in a one-to-one correspondence, and the first end of the coil is used to be connected to a first power supply a second diode connected in parallel to both ends of the coil; A second triode, comprising a second base, a second collector and a second emitter, wherein the second collector is connected to the second end of the coil, and the second base is connected to the output end of the three-phase power input protection circuit; A fourth capacitor is connected in series between the second base and the ground; The tenth resistor is connected in series between the second emitter and the ground.

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