CN221080910U - Contactor undervoltage protection circuit, control panel and air conditioner - Google Patents

Abstract

The utility model discloses a contactor undervoltage protection circuit, a control board and an air conditioner, wherein the contactor undervoltage protection circuit comprises a voltage detection circuit; the voltage stabilizing tube is connected in series between the non-inverting input end and the inverting input end of the voltage detection circuit; a control circuit; when the voltage value of the voltage detection signal is not smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is conducted, and a high-level trigger signal is output to the control circuit so as to trigger the control circuit to control the contactor to be closed; when the voltage value of the voltage detection signal is smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is turned off, and the control circuit stops outputting a high-level trigger signal to the control circuit so that the control circuit controls the contactor to be disconnected; the technical scheme of the utility model aims to reduce the situation that the contact points of the contactor are damaged due to overcurrent because the contactor cannot be timely protected when the existing equipment is in a low-voltage working environment.

Description

Contactor undervoltage protection circuit, control panel and air conditioner

Technical Field

The utility model relates to the technical field of contactors, in particular to an under-voltage protection circuit, a control board and an air conditioner of a contactor.

Background

At present, a contactor is often adopted for controlling high-power loads such as a constant-speed compressor in air conditioning equipment, however, if the equipment is in a low-voltage working environment for a long time due to a power grid, the working current of a motor can be increased due to the fixed power of the motor. This can lead to an increase in the temperature of the contactor contacts at the control end, which cannot be timely protected, and thus to damage of the contactor contacts.

Disclosure of utility model

The utility model mainly aims to provide a contactor under-voltage protection circuit, a control board and an air conditioner, and aims to reduce the situation that the contacts of the contactor are damaged due to overcurrent because the contactor cannot be timely protected when the existing equipment is in a low-voltage working environment.

In order to achieve the above object, the present utility model provides a contactor undervoltage protection circuit, which is applied to an air conditioner, the air conditioner includes a contactor, the contactor undervoltage protection circuit includes:

The voltage detection circuit is provided with a normal phase input end, an opposite phase input end, a normal phase output end and an opposite phase output end, wherein the normal phase input end is used for being connected with a live wire of any phase input voltage of the contactor, and the opposite phase input end is used for being connected with a zero line of the input voltage and outputting a corresponding voltage detection signal;

the voltage stabilizing tube is connected in series between the positive phase output end and the negative phase output end of the voltage detection circuit;

The input end of the control circuit is electrically connected with the cathode of the voltage stabilizing tube, and the output end of the control circuit is electrically connected with the contactor;

When the voltage value of the voltage detection signal is not smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is conducted, and a high-level trigger signal is output to the control circuit so as to trigger the control circuit to control the contactor to be closed; and when the voltage value of the voltage detection signal is smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is turned off, and the control circuit stops outputting a high-level trigger signal to the control circuit so that the control circuit controls the contactor to be turned off.

In some embodiments, the air conditioner further comprises a relay and a controller, the control circuit comprising:

the first end of the first resistor is connected with the cathode of the voltage stabilizing tube;

the second end of the second resistor is connected with the anode of the voltage stabilizing tube;

The input end of the switching tube is electrically connected with the voltage detection circuit, and the controlled end of the switching tube is connected with the second end of the first resistor;

The anode of the light emitting side of the optocoupler is connected with the output end of the switch tube, the cathode of the light emitting side of the optocoupler is connected with the first end of the second resistor, the input end of the receiving side of the optocoupler is used for being connected with a direct current power supply through a relay, and the output end of the receiving side of the optocoupler is used for being electrically connected with the controller.

In some embodiments, the voltage detection circuit includes:

The input end of the acquisition circuit is used for accessing the input voltage, and the acquisition circuit is also used for outputting corresponding direct current acquisition current according to the accessed input voltage;

The input end of the current-voltage conversion circuit is connected with the output end of the acquisition circuit, and the output end of the current-voltage conversion circuit is electrically connected with the voltage stabilizing tube and is used for carrying out current-voltage conversion processing on the accessed direct current acquisition current and outputting a corresponding voltage detection signal to the voltage stabilizing tube.

In some embodiments, the current-to-voltage conversion circuit comprises:

the third resistor is connected in parallel between the positive input end and the negative input end of the acquisition circuit and is used for outputting corresponding acquisition voltage according to the accessed direct current acquisition current;

And the fourth resistor is connected in series between the positive input end of the acquisition circuit and the cathode of the voltage stabilizing tube and is used for dividing the accessed acquisition voltage and outputting the divided acquisition voltage to the voltage stabilizing tube.

In some embodiments, the acquisition circuit comprises:

The system comprises an alternating current transformer, a first end of a primary side of the alternating current transformer is used for being connected with a live wire of the input voltage, a second end of the primary side of the alternating current transformer is used for being connected with a zero line of the input voltage, and the alternating current transformer is also used for collecting the current voltage of the input voltage and outputting corresponding alternating current collection current;

And the input end of the rectifying circuit is electrically connected with the secondary side of the alternating current transformer, and the output end of the rectifying circuit is electrically connected with the current-voltage conversion circuit and is used for outputting corresponding direct current acquisition current after rectifying the accessed alternating current acquisition current.

In some embodiments, the acquisition circuit further comprises:

The input end of the current limiting resistor is used for being connected with a live wire of the input voltage, the output end of the current limiting resistor is connected with the first end of the primary side of the alternating current transformer, and the current limiting resistor is also used for outputting the connected input voltage after current limiting treatment.

In some embodiments, the voltage detection circuit further comprises:

The first capacitor and the second capacitor are connected in parallel between the positive output end and the negative output end of the acquisition circuit and are used for carrying out filtering treatment on the rectified direct current acquisition current and outputting the direct current acquisition current to the current-voltage conversion circuit.

In some embodiments, the air conditioner further includes a controller, and the two output ends of the control circuit include a first output end and a second output end;

The first output end of the control circuit is used for being connected with the contactor, and the second output end of the control circuit is used for being connected with the controller;

The control circuit is also used for outputting a high-level contactor state signal to the controller when receiving a high-level trigger signal output by the voltage stabilizing tube; and outputting a low-level contactor state signal when the high-level trigger signal output by the voltage regulator tube is not received.

The utility model also provides a control board, which comprises a PCB, a relay, a controller and the contactor undervoltage protection circuit;

The contactor undervoltage protection circuit is respectively and electrically connected with the controller and the relay and is integrated on the PCB together; the relay and the contactor undervoltage protection circuit are respectively used for being electrically connected with the contactor.

The utility model also provides an air conditioner which comprises a contactor, a functional load and the control panel;

The control board is used for collecting the current voltage of any input voltage of the contactor and controlling the on/off of the contactor according to the current voltage; and controlling the working state of the functional load according to the on/off state of the contactor.

According to the technical scheme, the voltage detection circuit is arranged to collect the input voltage of the contactor, so that the contactor can be detected before the power is input into the contactor, the voltage stabilizing tube is arranged to trigger the control circuit, and the control circuit directly cuts off the output of the relay when the voltage stabilizing tube stops conducting through logic control, so that the design difficulty of the undervoltage protection circuit is reduced, the control time is shortened, the contactor can be timely disconnected when the undervoltage input voltage flows into the contactor, and the contactor is prevented from being damaged due to the fact that the undervoltage high current is connected into the contactor.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an embodiment of an under-voltage protection circuit of a contactor according to the present utility model;

FIG. 2 is a schematic diagram of another embodiment of an under-voltage protection circuit of the contactor according to the present utility model;

FIG. 3 is a schematic diagram of an embodiment of an under-voltage protection circuit of the contactor according to the present utility model;

FIG. 4 is a schematic diagram of an embodiment of an under-voltage protection circuit of the contactor according to the present utility model;

fig. 5 is a circuit configuration diagram of an embodiment of the undervoltage protection circuit of the contactor of the present utility model.

Reference numerals illustrate:

Reference numerals	Name of the name	Reference numerals	Name of the name
				100	Voltage detection circuit	300	Control circuit
110	Acquisition circuit	IC1	Optical coupler
				111	AC mutual inductor	Q1	Switch tube
112	Rectifying circuit	C1～C2	First capacitor-second capacitor
				120	Current-voltage conversion circuit	RL	Current limiting resistor
200	Voltage stabilizing tube	R1～R4	First to fourth resistors

The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The utility model provides a contactor undervoltage protection circuit which is applied to an air conditioner.

Referring to fig. 1, in an embodiment, the air conditioner includes a contactor, and the contactor under-voltage protection circuit includes:

The voltage detection circuit 100 is provided with a normal phase input end, an inverted input end, a normal phase output end and an inverted output end, wherein the normal phase input end is used for being connected with a live wire of any phase input voltage of the contactor, and the inverted input end is used for being connected with a zero line of the input voltage and outputting a corresponding voltage detection signal;

The voltage stabilizing tube 200 is connected in series between a positive phase output end and a negative phase output end of the voltage detection circuit 100;

the input end of the control circuit 300 is electrically connected with the cathode of the voltage stabilizing tube 200, and the output end of the control circuit 300 is electrically connected with the contactor;

When the voltage value of the voltage detection signal is not less than the breakdown voltage of the voltage stabilizing tube 200, the voltage stabilizing tube 200 is conducted, and a high-level trigger signal is output to the control circuit 300 to trigger the control circuit 300 to control the contactor to be closed; and when the voltage value of the voltage detection signal is smaller than the breakdown voltage of the voltage regulator 200, the voltage regulator 200 is turned off, and the output of the high-level trigger signal to the control circuit 300 is stopped, so that the control circuit 300 controls the contactor to be opened.

In this embodiment, when the contactor is a dc contactor, the voltage detection circuit 100 may include a dc voltage detection circuit 100 formed by a voltage dividing resistor and/or a comparator, and when the contactor is an ac contactor, the voltage detection circuit 100 may include an ac transformer 111; the control circuit 300 may include a switch isolation circuit formed by devices such as a switch tube Q1 and a comparator and an optocoupler IC 1.

In the air conditioner, the contactor is usually affected by low voltage and high current, and the contactor is welded to cause damage, in order to prevent the situation, the contactor is usually made of high temperature resistant material instead of the contactor, and the shell is also required to be made of high temperature resistant plastic, so that the material cost and the production process requirement of the device are greatly increased, or the temperature detection is increased in the shell of the alternating current contactor, but the installation difficulty and the cost are increased.

Therefore, the voltage detection circuit 100, the voltage stabilizing tube 200 and the control circuit 300 are integrated in the control panel of the air conditioner, the input voltage of the contactor is collected through the voltage detection circuit 100, so that the detection can be performed before the power is input into the contactor, the voltage stabilizing tube 200 is adopted to trigger the control circuit 300, when the voltage stabilizing tube 200 stops conducting through logic control, the control circuit 300 directly cuts off the output of the relay, calculation and control are not needed through software, the design cost of the control circuit 300 is reduced, the control time is shortened, and the contactor under-voltage protection circuit can timely cut off the contactor when the under-voltage input voltage flows into the contactor, so that the contactor is prevented from being damaged due to the fact that the under-voltage heavy current is connected.

Specifically, when the air conditioner works normally, the voltage detection circuit 100 collects the input voltage of the access contactor in real time, and outputs a corresponding voltage detection signal according to the collected input voltage, wherein the voltage value of the voltage detection signal is positively correlated with the input voltage, and when the input voltage is larger, the voltage value of the voltage detection signal is also larger, so that the breakdown voltage of the voltage stabilizing tube 200 is set to represent the normal working voltage, such as 220V. When the input voltage can reach the normal working voltage, the voltage detection signal breaks down the voltage stabilizing tube 200, so that the controlled end of the control circuit 300 forms a current loop through the voltage stabilizing tube 200, the voltage stabilizing values at the two ends of the voltage stabilizing tube 200 are used as high-level trigger signals to be connected into the control circuit 300, and the control circuit 300 is triggered to output corresponding closing control signals, so that the contactor is connected; when the input voltage does not reach the normal working voltage, the voltage detection signal cannot break down the voltage stabilizing tube 200, the controlled end of the control circuit 300 is suspended, and cannot be connected with a high-level trigger signal, so that the control circuit 300 outputs a corresponding disconnection control signal to turn off the contactor.

The utility model can detect before the power is input into the contactor by setting the voltage detection circuit 100 to collect the input voltage of the contactor, and the voltage stabilizing tube 200 is set to trigger the control circuit 300, so that the control circuit 300 directly cuts off the output of the relay when the voltage stabilizing tube 200 stops conducting through logic control, thereby not only reducing the design difficulty of the undervoltage protection circuit, but also shortening the control time, and leading the undervoltage protection circuit of the contactor to be capable of timely cutting off the contactor when the undervoltage input voltage flows into the contactor, and preventing the contactor from being damaged due to the connection of low-voltage heavy current.

Referring to fig. 1 and 5, in an embodiment, the air conditioner further includes a relay and a controller, and the control circuit 300 includes:

A first resistor R1, wherein a first end of the first resistor R1 is connected with the cathode of the voltage stabilizing tube 200;

a second resistor R2, wherein a second end of the second resistor R2 is connected with the anode of the voltage stabilizing tube 200;

the input end of the switching tube Q1 is electrically connected with the voltage detection circuit 100, and the controlled end of the switching tube Q1 is connected with the second end of the first resistor R1;

The light-emitting side anode of the light-coupling IC1 is connected with the output end of the switch tube Q1, the light-emitting side cathode of the light-coupling IC1 is connected with the first end of the second resistor R2, the receiving side input end of the light-coupling IC1 is used for being connected with a direct current power supply through a relay, and the receiving side output end of the light-coupling IC1 is used for being electrically connected with the controller.

In this embodiment, the switching tube Q1 may include any one of devices such as a MOS tube, a switching tube, and a thyristor.

When the control circuit 300 works normally, the input end of the switching tube Q1 is connected to the dc power supply output by the voltage detection circuit 100 in real time, and the voltage of the voltage detection signal is limited by the first resistor R1 and then output to the controlled end of the switching tube Q1. When the input voltage can reach the normal working voltage, the voltage detection signal breaks down the voltage stabilizing tube 200, the voltage stabilizing values at two ends of the voltage stabilizing tube 200 are used as high-level trigger signals to be connected to the controlled end of the switching tube Q1, so that the switching tube Q1 is conducted under the control of the high level, the light emitting diode in the optocoupler IC1 is controlled to emit light, after the receiving side is sensitized and conducted, the direct current power supply is connected with the current loop through the magnetic core side of the relay, the switching side of the relay is attracted, the control signals can be connected to the contactor, and the controller is controlled to be conducted; when the input voltage does not reach the normal working voltage, the voltage detection signal cannot break down the voltage stabilizing tube 200, so that the switching tube Q1 is turned off due to the suspension of the control end, and the light emitting diode in the optocoupler IC1 stops emitting light, therefore, the receiving side of the optocoupler IC1 disconnects a current loop formed by the direct current power supply, the magnetic core side of the relay and the ground, the switching side of the relay is turned off, the control signal cannot be connected into the contactor, and the controller is controlled to be turned off.

Referring to fig. 1 and 2, in one embodiment, the voltage detection circuit 100 includes:

The input end of the acquisition circuit 110 is used for accessing the input voltage, and the acquisition circuit 110 is also used for outputting corresponding direct current acquisition current according to the accessed input voltage;

The input end of the current-voltage conversion circuit 120 is connected with the output end of the acquisition circuit 110, and the output end of the current-voltage conversion circuit 120 is electrically connected with the voltage stabilizing tube 200, so as to perform current-voltage conversion processing on the accessed dc acquisition current and output a corresponding voltage detection signal to the voltage stabilizing tube 200.

In this embodiment, the contactor is an ac contactor; the current-voltage conversion circuit 120 may include a resistor, or may include a conversion circuit including an operational amplifier and its peripheral circuits.

When the voltage detection circuit 100 works normally, the acquisition circuit 110 acquires any phase of input voltage accessed by the ac contactor and outputs a corresponding dc acquisition current, wherein the current value of the dc acquisition current is positively correlated with the input voltage, and when the input voltage is larger, the current value of the dc acquisition current is larger. Therefore, when the current-voltage conversion circuit 120 performs conversion, the converted dc acquisition voltage, i.e., the voltage detection signal, is also proportional to the input voltage.

Referring to fig. 2 and 5, in one embodiment, the current-to-voltage conversion circuit 120 includes:

A third resistor R3, where the third resistor R3 is connected in parallel between the non-inverting input end and the inverting input end of the acquisition circuit 110, and is configured to output a corresponding acquisition voltage according to the accessed dc acquisition current;

and a fourth resistor R4, where the fourth resistor R4 is connected in series between the positive input end of the acquisition circuit 110 and the cathode of the voltage regulator 200, and is configured to divide the connected acquisition voltage and output the divided acquisition voltage to the voltage regulator 200.

In this embodiment, when the voltage detection circuit 100 works normally, the acquisition circuit 110 outputs a dc acquisition current corresponding to an input voltage to the current-voltage conversion circuit 120 through the ac contactor, the dc acquisition current is converted into a voltage by the third resistor R3, the voltage at two ends of the third resistor R3 is divided by the fourth resistor R4 and then output to the regulator 200, for example, when the input voltage of the contactor is 220V, the current value output by the acquisition circuit 110 is 5.1mA, the resistance value of the third resistor R3 is 2.4K, the voltage applied at two ends of the third resistor R3 is about 5.1ma×2.4k=12.24v, and if the breakdown voltage of the regulator 200 is 11V, the voltage at two ends of the regulator 200DZ1 is 12.24V-0.7v=11.7v, and is higher than the breakdown voltage, so that the current value at the time of the contactor is in a reverse breakdown region, the switch tube Q1 is turned on, the optocoupler IC1 is turned on, and the control board can control the ac air conditioner by controlling the contactor RY 1; similarly, when the input voltage of the contactor is lower than the normal working voltage by 200V, the current value output by the acquisition circuit 110 is 4.64mA, and the voltage applied to the two ends of the third resistor R3 is about 4.65mA, 2.4k=11.14v, and the voltage of the two ends of the voltage stabilizing tube 200DZ1 is 10.44V, which is lower than the breakdown voltage thereof, so that the switching tube Q1 is in a cut-off region, the optocoupler IC1 is cut-off, and at the moment, the air conditioner control board cannot control the contactor through the relay RY1, and the contactor is in a cut-off protection state, thereby realizing an automatic protection function.

Referring to fig. 1 to 5, in an embodiment, the acquisition circuit 110 includes:

The first end of the primary side of the alternating current transformer 111 is used for being connected with a live wire of the input voltage, the second end of the primary side of the alternating current transformer 111 is used for being connected with a zero line of the input voltage, and the alternating current transformer 111 is also used for collecting the current voltage of the input voltage and outputting corresponding alternating current collection current;

And the input end of the rectifying circuit 112 is electrically connected with the secondary side of the ac transformer 111, and the output end of the rectifying circuit 112 is electrically connected with the current-voltage conversion circuit 120, so as to output a corresponding dc collection current after rectifying the connected ac collection current.

In this embodiment, the ac transformer 111 may be a milliamp-level current transformer; the rectifying circuit 112 may include a full bridge rectifying circuit 112 composed of a plurality of diodes.

When the voltage detection circuit 100 works normally, the high-precision current transformer takes an input voltage from one phase of the three-phase input power supply of the input contactor, and converts the input voltage into a corresponding current according to the working principle of the transformer, and further, the acquisition circuit 110 further includes: the input end of the current limiting resistor RL is used for being connected with a live wire of the input voltage, the output end of the current limiting resistor RL is connected with the first end of the primary side of the alternating current transformer 111, and the current limiting resistor RL is also used for carrying out current limiting processing on the connected input voltage and then outputting the processed input voltage. Thus, if the input power is a normal 220V ac power, the current limiting resistor RL of the current transformer is 43K, and the internal resistance of the primary coil of the current transformer is 110K, then the working currents of the primary and secondary coils of the transformer are: uin/(rl+r0) =220V/(43k+110k) =5.1 mA. Wherein Uin is input voltage, RL is a current limiting resistor RL of the current transformer, and R0 is the primary coil internal resistance of the current transformer. Thereby rectifying the alternating current of 5.1mA by the rectifying circuit 112 and outputting the direct current collecting current of 5.1mA to the current-voltage converting circuit 120.

Further, the voltage detection circuit 100 further includes:

The first capacitor C1 and the second capacitor C2 are connected in parallel between the positive output end and the negative output end of the collecting circuit 110, and are used for filtering the rectified dc collecting current and outputting the filtered dc collecting current to the current-voltage converting circuit 120.

In this embodiment, at least one kiloμ -level large-capacity capacitor exists in the first capacitor C1 and the second capacitor C2, so as to implement filtering of the rectified dc collection current.

Referring to fig. 1 to 5, in an embodiment, the air conditioner further includes a controller, and the two output ends of the control circuit 300 include a first output end and a second output end;

A first output end of the control circuit 300 is used for being connected with the contactor, and a second output end of the control circuit 300 is used for being connected with a controller;

The control circuit 300 is further configured to output a high-level contactor status signal to the controller when receiving a high-level trigger signal output by the voltage regulator 200; and outputting a low-level contactor status signal when the high-level trigger signal output from the regulator 200 is not received.

In this embodiment, the air conditioning contactor may receive different loads, such as a fixed frequency compressor, an electric heater, an ac tap motor, etc., and these high power loads are all controlled by the contactor, so feedback is required to the current switching state of the contactor.

When the control circuit 300 works normally, if the input voltage can reach the normal working voltage, the voltage detection signal breaks down the voltage stabilizing tube 200, the voltage stabilizing value at two ends of the voltage stabilizing tube 200 is used as a high-level trigger signal to be connected to the controlled end of the switching tube Q1, so that the switching tube Q1 is conducted under the control of the high level, the light emitting diode in the optocoupler IC1 is controlled to emit light, after the receiving side is sensitized and conducted, a current loop is formed between the direct current power supply and the magnetic core of the relay through the port of the controller and the ground side, and thus the high-level feedback signal is input into the controller, and the controller can determine that the contactor is in a connection state according to the connected feedback signal, and drives the load according to the user requirement; when the input voltage does not reach the normal working voltage, the voltage detection signal cannot break down the voltage stabilizing tube 200, so that the switching tube Q1 is turned off due to the fact that the control end is suspended, and the light emitting diode in the optocoupler IC1 stops emitting light, therefore, the receiving side of the optocoupler IC1 disconnects a current loop formed by the direct-current power supply, the magnetic core side of the relay and the controller and the ground, the port of the controller is suspended, and the controller determines that the contactor is in a turn-off state due to the fact that the controller is not connected with the feedback signal, and stops driving the load.

The utility model also provides a control board, which comprises a PCB, a relay, a controller and the contactor undervoltage protection circuit, wherein the specific structure of the contactor undervoltage protection circuit refers to the embodiment, and the control board adopts all the technical schemes of all the embodiments, so that the control board at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.

The utility model also provides an air conditioner which comprises a contactor, a functional load and the control panel, wherein the specific structure of the control panel refers to the embodiment, and the air conditioner at least has all the beneficial effects brought by the technical proposal of the embodiment because the air conditioner adopts all the technical proposal of the embodiment, and the detailed description is omitted.

The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims (10)

1. The utility model provides a contactor undervoltage protection circuit, is applied to the air conditioner, the air conditioner includes the contactor, its characterized in that, contactor undervoltage protection circuit includes:

The voltage detection circuit is provided with a normal phase input end, an opposite phase input end, a normal phase output end and an opposite phase output end, wherein the normal phase input end is used for being connected with a live wire of any phase input voltage of the contactor, and the opposite phase input end is used for being connected with a zero line of the input voltage and outputting a corresponding voltage detection signal;

the voltage stabilizing tube is connected in series between the positive phase output end and the negative phase output end of the voltage detection circuit;

The input end of the control circuit is electrically connected with the cathode of the voltage stabilizing tube, and the output end of the control circuit is electrically connected with the contactor;

When the voltage value of the voltage detection signal is not smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is conducted, and a high-level trigger signal is output to the control circuit so as to trigger the control circuit to control the contactor to be closed; and when the voltage value of the voltage detection signal is smaller than the breakdown voltage of the voltage stabilizing tube, the voltage stabilizing tube is turned off, and the control circuit stops outputting a high-level trigger signal to the control circuit so that the control circuit controls the contactor to be turned off.

2. The contactor undervoltage protection circuit of claim 1, said air conditioner further comprising a relay and a controller, wherein said control circuit comprises:

the first end of the first resistor is connected with the cathode of the voltage stabilizing tube;

the second end of the second resistor is connected with the anode of the voltage stabilizing tube;

The input end of the switching tube is electrically connected with the voltage detection circuit, and the controlled end of the switching tube is connected with the second end of the first resistor;

The anode of the light emitting side of the optocoupler is connected with the output end of the switch tube, the cathode of the light emitting side of the optocoupler is connected with the first end of the second resistor, the input end of the receiving side of the optocoupler is used for being connected with a direct current power supply through a relay, and the output end of the receiving side of the optocoupler is used for being electrically connected with the controller.

3. The contactor undervoltage protection circuit of claim 1, wherein the voltage detection circuit comprises:

The input end of the acquisition circuit is used for accessing the input voltage, and the acquisition circuit is also used for outputting corresponding direct current acquisition current according to the accessed input voltage;

The input end of the current-voltage conversion circuit is connected with the output end of the acquisition circuit, and the output end of the current-voltage conversion circuit is electrically connected with the voltage stabilizing tube and is used for carrying out current-voltage conversion processing on the accessed direct current acquisition current and outputting a corresponding voltage detection signal to the voltage stabilizing tube.

4. The contactor undervoltage protection circuit of claim 3, wherein said current to voltage conversion circuit comprises:

the third resistor is connected in parallel between the positive input end and the negative input end of the acquisition circuit and is used for outputting corresponding acquisition voltage according to the accessed direct current acquisition current;

And the fourth resistor is connected in series between the positive input end of the acquisition circuit and the cathode of the voltage stabilizing tube and is used for dividing the accessed acquisition voltage and outputting the divided acquisition voltage to the voltage stabilizing tube.

5. The contactor undervoltage protection circuit of claim 3, wherein said acquisition circuit comprises:

The system comprises an alternating current transformer, a first end of a primary side of the alternating current transformer is used for being connected with a live wire of the input voltage, a second end of the primary side of the alternating current transformer is used for being connected with a zero line of the input voltage, and the alternating current transformer is also used for collecting the current voltage of the input voltage and outputting corresponding alternating current collection current;

And the input end of the rectifying circuit is electrically connected with the secondary side of the alternating current transformer, and the output end of the rectifying circuit is electrically connected with the current-voltage conversion circuit and is used for outputting corresponding direct current acquisition current after rectifying the accessed alternating current acquisition current.

6. The contactor undervoltage protection circuit of claim 5, wherein said acquisition circuit further comprises:

The input end of the current limiting resistor is used for being connected with a live wire of the input voltage, the output end of the current limiting resistor is connected with the first end of the primary side of the alternating current transformer, and the current limiting resistor is also used for outputting the connected input voltage after current limiting treatment.

7. The contactor undervoltage protection circuit of claim 3, wherein said voltage detection circuit further comprises:

The first capacitor and the second capacitor are connected in parallel between the positive output end and the negative output end of the acquisition circuit and are used for carrying out filtering treatment on the rectified direct current acquisition current and outputting the direct current acquisition current to the current-voltage conversion circuit.

8. The contactor undervoltage protection circuit of claim 1, the air conditioner further comprising a controller, wherein the control circuit has two output terminals, including a first output terminal and a second output terminal;

The first output end of the control circuit is used for being connected with the contactor, and the second output end of the control circuit is used for being connected with the controller;

The control circuit is also used for outputting a high-level contactor state signal to the controller when receiving a high-level trigger signal output by the voltage stabilizing tube; and outputting a low-level contactor state signal when the high-level trigger signal output by the voltage regulator tube is not received.

9. A control board, characterized in that the control board comprises a PCB board, a relay, a controller and the contactor undervoltage protection circuit according to claims 1-8;

The contactor undervoltage protection circuit is respectively and electrically connected with the controller and the relay and is integrated on the PCB together; the relay and the contactor undervoltage protection circuit are respectively used for being electrically connected with the contactor.

10. An air conditioner comprising a contactor, a functional load, and the control board according to claim 9;

The control board is used for collecting the current voltage of any input voltage of the contactor and controlling the on/off of the contactor according to the current voltage; and controlling the working state of the functional load according to the on/off state of the contactor.