Water pump on-off control circuit and air conditioner

Abstract

The utility model relates to a water pump on-off control circuit and an air conditioner. The circuit comprises a rectification circuit, a voltage comparison circuit, an isolation circuit, a main control circuit and a water pump control circuit. The rectifying circuit is connected with an alternating current power supply and the voltage comparison circuit and is used for rectifying alternating current and outputting alternating current comparison voltage; the voltage comparison circuit is also connected with the isolation circuit and is used for comparing the alternating-current comparison voltage with a preset zero-point voltage and outputting a first level signal; the isolation circuit is also connected with the main control circuit and is used for outputting a second level signal according to the first level signal; the main control circuit is further connected with the water pump control circuit and used for outputting a control signal to control on-off of the water pump when the second level signal is low level. By detecting whether the alternating current crosses the zero-point voltage or not and controlling the on-off of the alternating-current water pump near the alternating-current zero-point voltage, generation of electric arcs can be reduced, electromagnetic interference can be reduced, damage to equipment such as a relay can be avoided, and the safety and reliability of control over the alternating-current water pump are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioner control, and particularly relates to a water pump on-off control circuit and an air conditioner. BACKGROUND

[0002] The control method of the current air conditioning system is relatively basic and direct, mainly relying on electromagnetic relays as the core control components. This method is that when the water pump needs to be started to promote the cooling liquid circulation of the air conditioning system, the control system sends a signal to the electromagnetic relay, so that the internal contact of the electromagnetic relay is closed, thereby connecting the alternating current power supply with the water pump motor, and the water pump starts to work. On the contrary, when the system detects that further cooling is not needed or the preset condition needs to stop the water pump, the control system sends an instruction to the relay again, so that the contact of the relay is disconnected, the power supply of the water pump is cut off, and the water pump stops running.

[0003] However, this control method faces a problem that cannot be ignored in actual application: in the moment of power closing and cutting off, the alternating current water pump, as a typical inductive load, will generate a momentary high voltage in the inductor coil inside it, which is often accompanied by the generation of a large arc. The arc not only causes wear and tear to the relay contact, shortening its service life, but also releases strong electromagnetic interference. This interference signal may propagate along the power supply line, affecting the stability and reliability of the entire air conditioning control system, and even interfering with other electronic devices connected thereto, such as sensors, controllers, etc., leading to misoperation or performance degradation. More seriously, the generation of the arc may also cause safety hazards, such as causing a short circuit in the circuit, increasing the risk of fire, etc.

[0004] It can be seen that in the control of the alternating current water pump of the air conditioner, how to reduce the generation of the arc, reduce or avoid damage to the relay and other devices, so as to improve the safety and reliability of the alternating current water pump control becomes particularly important. Invention content

[0005] The present application provides a water pump on-off control circuit and an air conditioner to solve the technical problem of damage to the relay and other devices caused by the generation of a large arc in the existing air conditioner alternating current water pump control, and low safety and reliability.

[0006] According to one aspect of the embodiments of the present application, the present application provides a water pump breaking control circuit, comprising a rectifier circuit, a voltage comparison circuit, an isolation circuit, a main control circuit and a water pump control circuit; a first end of the rectifier circuit is connected with an AC power supply, a second end of the rectifier circuit is connected with a first end of the voltage comparison circuit, for AC rectification and outputting an AC comparison voltage; a second end of the voltage comparison circuit is connected with a first end of the isolation circuit, for comparison according to the AC comparison voltage and a preset zero voltage, and outputting a first level signal; a second end of the isolation circuit is connected with a first end of the main control circuit, for outputting a second level signal according to the first level signal, and when the second level signal is a low level, the AC power supply is at a zero voltage; a second end of the main control circuit is connected with a first end of the water pump control circuit, and a second end of the water pump control circuit is connected with the AC power supply, for receiving the second level signal, and inputting a control signal to the water pump control circuit when the second level signal is a low level to control the water pump breaking.

[0007] Optionally, the rectifier circuit comprises a rectifier bridge, a first input end of the rectifier bridge is connected with a live wire of the AC power supply, a second input end of the rectifier bridge is connected with a neutral wire of the AC power supply, a first output end of the rectifier bridge is connected with the voltage comparison circuit, and a second output end of the rectifier bridge is grounded.

[0008] Optionally, the voltage comparison circuit comprises a comparator, a voltage dividing unit, a positive phase end low pass filter unit, a negative phase end low pass filter unit, a first pull-up resistor, a first diode and a first resistor; a positive phase input end of the comparator is connected with a first end of the positive phase end low pass filter unit, and a negative phase input end of the comparator is connected with a first end of the negative phase end low pass filter unit; a second end of the positive phase end low pass filter unit is connected with a first end of the voltage dividing unit, a second end of the negative phase end low pass filter unit is connected with a first output end of the rectifier bridge, a second end of the voltage dividing unit is connected with a second output end of the rectifier bridge and grounded, and a third end of the voltage dividing unit is connected with an external power supply; the first diode is connected in series between an output end of the comparator and the isolation circuit, a first end of the first pull-up resistor is connected with the external power supply, a second end of the first pull-up resistor is connected between the output end of the comparator and a positive electrode of the first diode, a first end of the first resistor is connected with a negative electrode of the first diode, and a second end of the first resistor is grounded.

[0009] Optionally, the voltage dividing unit comprises a second resistor and a third resistor, one end of the second resistor is connected with the external power supply, one end of the third resistor is grounded, and the other ends of the second resistor and the third resistor are commonly connected with the second end of the positive phase end low pass filter unit, for inputting the preset zero voltage to the positive phase end of the comparator.

[0010] Optionally, the low-pass filter unit at the negative phase end comprises a fourth resistor, a first capacitor and a second capacitor, one end of the fourth resistor is connected to the first output end of the rectifier bridge, the other end of the fourth resistor is connected to the negative phase input end of the comparator, the first capacitor and the second capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected between the negative phase input end of the comparator and the fourth resistor; the low-pass filter unit at the positive phase end comprises a fifth resistor, a third capacitor and a fourth capacitor, one end of the fifth resistor is connected to the common end of the second resistor and the third resistor, the other end of the fifth resistor is connected to the positive phase input end of the comparator, the third capacitor and the fourth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected between the positive phase input end of the comparator and the fifth resistor.

[0011] Optionally, the isolation circuit comprises an optocoupler and a second pull-up resistor, the input end of the optocoupler is connected to the negative pole of the first diode, the first output end of the optocoupler is connected to the first end of the master control circuit to output the second level signal to the master control circuit, the second output end of the optocoupler is grounded, and one end of the second pull-up resistor is connected to the output end of the optocoupler, and the other end of the second pull-up resistor is grounded.

[0012] Optionally, the master control circuit comprises a control chip, a signal receiving pin of the control chip serves as the first end of the master control circuit to receive the second level signal, and a signal control pin of the control chip serves as the second end of the master control circuit to output a control signal to the water pump control circuit for water pump on-off control.

[0013] Optionally, the water pump control circuit comprises a relay, a second diode, an alternating current water pump interface, a resistance-capacitance module, a fifth capacitor and a sixth capacitor, the first end of the relay is connected to the second end of the master control circuit, the second end of the relay is connected to a charge pump, the third end of the relay is connected to the live wire of the alternating current power supply, and the fourth end of the relay is connected to the first end of the alternating current water pump interface; the positive pole of the second diode is connected to the second end of the master control circuit and the first end of the relay, the negative pole of the second diode is connected to the second end of the relay and the charge pump, the second end of the alternating current water pump interface is connected to the zero line of the alternating current power supply, one end of the resistance-capacitance module is connected to the first end of the alternating current water pump interface, the other end of the resistance-capacitance module is connected to the second end of the alternating current water pump interface, the fifth capacitor and the sixth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected to the charge pump.

[0014] Optionally, the filter circuit is further included, a first end of the filter circuit is connected to a second end of the voltage comparison circuit, and a second end of the filter circuit is connected to a first end of the isolation circuit, for filtering the first level signal output by the isolation circuit.

[0015] According to another aspect of the embodiments of the present application, the present application provides an air conditioner, which comprises the water pump opening and closing control circuit.

[0016] Compared with the related art, the above technical solution provided by the embodiments of the present application has the following advantages.

[0017] The water pump opening and closing control circuit provided by the embodiments of the present application compares the input AC comparison voltage and the preset zero voltage to the comparator, when the first level signal output by the voltage comparison circuit is high, it indicates that the AC voltage is near the zero voltage, and the strong and weak electric isolation is further performed by the isolation circuit and the second level signal is output to the main control circuit, the second level signal is input to the main control circuit as the judgment reference of the AC zero voltage, when the second level signal received by the main control circuit is low, it is judged that the AC voltage is near the zero voltage, at this time, the voltage in the circuit is very low and close to zero, the main control circuit outputs the control signal to the water pump control circuit to control the opening and closing of the AC water pump when the AC voltage is near the zero voltage, so that the electric field strength between the power supply electrodes of the AC water pump is very small, which is not enough to ionize the gas molecules or atoms, and thus the electric arc is not formed or weakened. It can be seen that, based on the voltage comparison circuit and the isolation circuit, the present application can not only determine whether the AC voltage is near the zero voltage, but also control the opening and closing of the water pump based on the main control circuit when the AC voltage is near the zero voltage, which can reduce the generation of the electric arc, further reduce the electromagnetic interference, and more favorably avoid damaging the relay and other devices, and improve the safety and reliability of the AC water pump control. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the accompanying drawings needed to be used in the embodiments or the related art description will be briefly introduced, and obviously, other drawings can be obtained by those skilled in the art without any creative labor.

[0020] Figure 1 The module schematic diagram of the optional water pump opening and closing control circuit provided by the embodiments of the present application is shown in the figure.

[0021] Figure 2A control flow diagram of an optional water pump opening and closing control circuit according to the embodiment of the application is provided.

[0022] Figure 3 A circuit diagram of an optional water pump opening and closing control circuit according to the embodiment of the application is provided.

[0023] Figure 4 A module diagram of another optional water pump opening and closing control circuit according to the embodiment of the application is provided.

[0024] BRIEF DESCRIPTION OF DRAWINGS: 1, rectifier circuit, 2, voltage comparison circuit, 3, isolation circuit, 4, main control circuit, 5, water pump control circuit, 6, filter circuit. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0026] The principles and structures of the application will be described in detail below with reference to the drawings and embodiments.

[0027] To solve the above-mentioned technical problems of low safety and reliability of existing air conditioner AC water pump control due to large arc.

[0028] In view of the above problems, the design idea of the application is to compare the input AC comparison voltage and the preset zero voltage to the comparator. When the first level signal output by the voltage comparison circuit is high, it indicates that the AC voltage is near the zero voltage. Further, the strong and weak electric isolation is performed by the isolation circuit and the second level signal is output to the main control circuit. When the second level signal received by the main control circuit is low, the AC voltage is near the zero voltage. At this time, the voltage in the circuit is very low, close to zero. The main control circuit outputs a control signal to the water pump control circuit to control the opening and closing of the AC water pump when the AC voltage is near the zero voltage. Therefore, the electric field strength between the power supply electrodes of the AC water pump is very small, which is not enough to ionize gas molecules or atoms, so that the arc is not formed or weakened. Not only can it be determined whether the AC voltage is near the zero voltage, but also the water pump can be controlled to open and close when the AC voltage is near the zero voltage. This can reduce the generation of arc and electromagnetic interference, and is more conducive to avoiding damage to the relay and other equipment, and improving the safety and reliability of AC water pump control.

[0029] In the embodiment of the present application, the water pump breaking control circuit comprises a rectifier circuit 1, a voltage comparison circuit 2, an isolation circuit 3, a main control circuit 4 and a water pump control circuit 5.

[0030] The first end of the rectifier circuit 1 is connected to an AC power supply, and the second end of the rectifier circuit 1 is connected to the first end of the voltage comparison circuit 2, for rectifying AC power and outputting an AC comparison voltage.

[0031] The second end of the voltage comparison circuit 2 is connected to the first end of the isolation circuit 3, for comparing the AC comparison voltage with a preset zero voltage and outputting a first level signal.

[0032] The second end of the isolation circuit 3 is connected to the first end of the main control circuit 4, for outputting a second level signal according to the first level signal, and when the second level signal is at a low level, the AC power is at a zero voltage.

[0033] The second end of the main control circuit 4 is connected to the first end of the water pump control circuit 5, and the second end of the water pump control circuit 5 is connected to the AC power supply, for receiving the second level signal and inputting a control signal to the water pump control circuit 5 to control the breaking of the water pump when the second level signal is at a low level.

[0034] Specifically, the rectifier circuit 1 can include a full-wave rectifier, a half-wave rectifier, etc. The rectifier circuit 1 can rectify the AC power input by the AC power supply to input an AC comparison voltage to the voltage comparison circuit 2, where the AC comparison voltage can be used as a basis signal for zero voltage judgment, and specifically can be a rectified AC voltage.

[0035] The voltage comparison circuit 2 has two inputs, including a positive phase input and a negative phase input. The negative phase input receives the AC comparison voltage, and the positive phase input receives a preset zero voltage. Then the voltage comparison circuit 2 compares the two input voltages to output a first level signal. The specific voltage value of the preset zero voltage can be set according to the voltage dividing resistors in the voltage comparison circuit 2, and the value is near zero voltage (0V). The specific voltage value of the preset zero voltage is slightly larger than 0V, for example, the specific voltage value of the preset zero voltage is 0.2V. The first level signal can be a low level signal or a high level signal. When the AC comparison voltage is greater than the preset zero voltage, the first level signal output by the voltage comparison circuit 2 is at a low level. When the AC comparison voltage is less than the preset zero voltage, the first level signal output by the voltage comparison circuit 2 is at a high level. When the first level signal is at a high level, it indicates that the AC power is near the preset zero voltage.

[0036] The isolation circuit 3 is used to realize strong and weak electric isolation, and outputs a second level signal according to a first level signal. When the first level signal is high, the second level signal is low, and the voltage near the zero point of alternating current is detected. When the first level signal is low, the second level signal is high, and the voltage near the zero point of alternating current is not detected. The main control circuit 4 is used to output a control signal when the second level signal is low. The water pump control circuit 5 is used to control the opening or closing of the water pump after receiving the control signal.

[0037] Further, when the first level signal is low, the second level signal output by the isolation circuit 3 is high. In this case, the main control circuit 4 receives the high level signal, which indicates that the voltage of the alternating current has not reached the preset zero point voltage. The main control circuit 5 inputs a low level signal to the water pump control circuit 5, and the water pump control circuit 5 is not powered. In this case, the alternating current water pump is continuously closed. When the first level signal is high, the second level signal output by the isolation circuit 3 is low. The main control circuit 4 receives the low level signal, which indicates that the voltage of the alternating current is near the zero point voltage. The main control circuit 4 inputs a low level signal to the water pump control circuit 5, and the water pump control circuit 5 is powered. In this case, the alternating current water pump is opened.

[0038] In some examples, in combination with Figure 2 As shown in FIG. 4, before the water pump opening and closing control is performed, the state of the alternating current water pump can also be detected by the main control circuit 4 to determine whether the alternating current water pump is opened and whether the alternating current water pump needs to be opened or closed. On the premise that the alternating current water pump needs to be opened / closed, the water pump opening / closing control is performed based on the water pump opening and closing control circuit.

[0039] In the embodiment of the present application, the comparator is inputted with the AC comparison voltage and the preset zero voltage for comparison. When the first level signal outputted by the voltage comparison circuit 2 is high, it indicates that the AC voltage is near the zero voltage at this time. The strong and weak electric isolation is further performed by the isolation circuit 3 and the second level signal is outputted to the main control circuit 4. The second level signal is inputted to the main control circuit 4 as the judgment reference of the AC zero voltage. When the second level signal received by the main control circuit 4 is low, it is judged that the AC voltage is near the zero voltage. At this time, the voltage in the circuit is very low and close to zero. The main control circuit 4 outputs the control signal to the water pump control circuit 5 to control the opening and closing of the AC water pump when the AC voltage is near the zero voltage. Therefore, the electric field strength between the power supply electrodes of the AC water pump is very small and is insufficient to ionize the gas molecules or atoms, so that the electric arc is not formed or weakened. It can be seen that the present application can not only determine whether the AC voltage is near the zero voltage based on the voltage comparison circuit 2 and the isolation circuit 3, but also can control the opening and closing of the water pump based on the main control circuit 4 when the AC voltage is near the zero voltage. In this way, the generation of the electric arc is reduced, the electromagnetic interference is reduced, and the safety and reliability of the AC water pump control are improved.

[0040] In some optional embodiments, in combination with Figure 3 As shown in the figure, the rectifier circuit 1 includes a rectifier bridge. The first input end of the rectifier bridge is connected to the live wire of the AC power supply. The second input end of the rectifier bridge is connected to the neutral wire of the AC power supply. The first output end of the rectifier bridge is connected to the voltage comparison circuit 2. The second output end of the rectifier bridge is grounded.

[0041] Specifically, Figure 3 In the embodiment, the rectifier bridge is UD1. The rectifier bridge UD1 can be a full-wave rectifier bridge. The first input end of the rectifier bridge UD1 is connected to the live wire (AC_L) of the AC power supply. The second input end is connected to the neutral wire (AC_N) of the AC power supply. The negative half-axis voltage of the AC power supply is converted to the positive half-axis voltage by the rectifier bridge UD1. The full-wave rectification of the AC power supply is realized. The stable AC comparison voltage is inputted to the negative phase end of the voltage comparison circuit 2 through the first output end.

[0042] In some optional embodiments, in combination with Figure 3 As shown in the figure, the voltage comparison circuit 2 includes a comparator, a voltage dividing unit, a positive phase end low-pass filter unit, a negative phase end low-pass filter unit, a first pull-up resistor, a first diode and a first resistor.

[0043] The positive phase input end of the comparator is connected to the first end of the positive phase end low-pass filter unit. The negative phase input end of the comparator is connected to the first end of the negative phase end low-pass filter unit.

[0044] The second end of the positive-phase end low-pass filter unit is connected to the first end of the voltage dividing unit, the second end of the negative-phase end low-pass filter unit is connected to the first output end of the rectifier bridge, the second end of the voltage dividing unit is connected to the second output end of the rectifier bridge and grounded, and the third end of the voltage dividing unit is connected to the external power supply;

[0045] The first diode is connected in series between the output end of the comparator and the isolation circuit 3, the first end of the first pull-up resistor is connected to the external power supply, the second end of the first pull-up resistor is connected between the output end of the comparator and the anode of the first diode, the first end of the first resistor is connected to the cathode of the first diode, and the second end of the first resistor is grounded.

[0046] Specifically, the comparator is U1, the first pull-up resistor is R1, the first diode is D1, and the first resistor is R2. The comparator U1 is a voltage comparator for comparing the AC comparison voltage with the preset zero voltage. The voltage dividing unit is used to divide the voltage VCC_C of the external power supply connected to the third end of the voltage dividing unit to generate the preset zero voltage, and provide the preset zero voltage for the positive-phase end of the comparator U1, that is, the preset zero voltage is preset according to the voltage dividing unit. The positive-phase end low-pass filter unit and the negative-phase end low-pass filter unit are combined to filter the common-mode interference signal of the comparator, so as to ensure that the comparator U1 obtains stable voltage input.

[0047] Further, the positive-phase input end (+) of the comparator U1 is connected to the first end of the positive-phase end low-pass filter unit, the negative-phase input end (-) is connected to the first end of the negative-phase end low-pass filter unit, the second end of the positive-phase end low-pass filter unit is connected to the first end of the voltage dividing unit, the second end of the negative-phase end low-pass filter unit is connected to the first output end of the rectifier bridge UD1, the voltage VCC_C provided by the external power supply is divided by the voltage dividing unit to obtain the preset zero voltage V_ZERO, and input to the positive-phase end of the comparator U1, and the AC comparison voltage is input to the negative-phase end of the comparator U1 through the first output end of the rectifier bridge UD1, the common-mode interference signal in the voltage input to the comparator U1 is filtered through the combination of the positive-phase end low-pass filter unit and the negative-phase end low-pass filter unit, and finally the voltage comparison is performed by the comparator U1 to output the first level signal.

[0048] Further, the unidirectional conductivity of the first diode D2 can determine the voltage signal transmission direction, not only input the first level signal to the isolation circuit 3 along the transmission direction, but also protect the comparator U2, avoiding the reverse charging condition. Meanwhile, the first pull-up resistor R1 and the first resistor R2 can constitute a voltage divider, providing a suitable working voltage for the isolation circuit 3. In addition, the output of the comparator U1 is an open-drain output, which can only output a low level. By connecting the first pull-up resistor R1 to the output terminal of the comparator U1 and the other end inputting VCC_C provided by the external power supply, the output level of the comparator U1 can be determined as a high level, ensuring that the comparator U1 can output a low level and a high level with the assistance of the first pull-up resistor R1. When the output is a high level, the alternating current is at the zero voltage point.

[0049] In some alternative embodiments, in combination with Figure 3 As shown, the voltage dividing unit includes a second resistor and a third resistor, one end of the second resistor is connected to the external power supply, one end of the third resistor is grounded, and the other ends of the second resistor and the third resistor are commonly connected to the second end of the non-inverting end low-pass filter unit, for inputting the preset zero voltage to the non-inverting end of the comparator.

[0050] Specifically, the voltage dividing unit can be composed of two resistors, more than two resistors, or a variable resistor such as a three-terminal potentiometer. The value of the preset zero voltage can be set according to the resistance values in the voltage dividing unit. In this embodiment, the voltage dividing unit is composed of the second resistor R3 and the third resistor R4, one end of the second resistor R3 is connected to the external power supply VCC_C, one end of the third resistor R4 is grounded, and the common end of the second resistor R3 and the third resistor R4 is connected to the non-inverting end of the non-inverting end low-pass filter unit and then to the non-inverting end of the comparator U1. The VCC_C is divided by the second resistor R3 and the third resistor R4, and the voltage obtained by the voltage division is the preset zero voltage V_ZERO, V_ZERO = VCC_C / (R7+R8)×R8, so that the preset zero voltage V_ZERO obtained by the voltage division is input to the non-inverting end of the comparator U1 as the judgment basis of the alternating current zero voltage.

[0051] In some alternative embodiments, in combination with Figure 3 As shown, the non-inverting end low-pass filter unit includes a fourth resistor, a first capacitor and a second capacitor, one end of the fourth resistor is connected to the first output end of the rectifier bridge, the other end of the fourth resistor is connected to the negative phase input end of the comparator, the first capacitor and the second capacitor are connected in parallel, one end of the parallel connection is grounded, and the other end is connected between the negative phase input end of the comparator and the fourth resistor.

[0052] The positive terminal low-pass filter unit comprises a fifth resistor, a third capacitor and a fourth capacitor, one end of the fifth resistor is connected to the common end of the second resistor and the third resistor, the other end of the fifth resistor is connected to the positive input terminal of the comparator, the third capacitor and the fourth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected between the positive input terminal of the comparator and the fifth resistor.

[0053] Specifically, the structure of the negative terminal low-pass filter unit can be kept consistent with that of the positive terminal low-pass filter unit, the negative terminal low-pass filter unit is connected to the negative terminal of the comparator U1, and the positive terminal low-pass filter unit is connected to the positive terminal of the comparator U1, and the two units jointly perform common-mode interference signal filtering on the voltage at the input terminal of the comparator U1. By allowing low-frequency signals to pass through and attenuating high-frequency signals through the low-pass filter, the addition of the low-pass filter at the input terminal of the comparator U1 can filter out high-frequency noise, including high-frequency components in the common-mode interference.

[0054] Further, the negative terminal low-pass filter unit comprises a fourth resistor R5, a first capacitor C1 and a second capacitor C2, and the positive terminal low-pass filter unit comprises a fifth resistor R6, a third capacitor C3 and a fourth capacitor C4. Connecting the two capacitors in parallel can increase the total capacitance value, thereby reducing the cutoff frequency of the low-pass filter and more effectively filtering out high-frequency signals, so that the comparator U1 can receive more stable and accurate alternating comparison voltages and preset zero voltages.

[0055] In some optional embodiments, the isolation circuit 3 comprises Figure 3 As shown, the isolation circuit 3 comprises an optocoupler and a second pull-up resistor.

[0056] The input terminal of the optocoupler is connected to the negative electrode of the first diode, the first output terminal of the optocoupler is connected to the first terminal of the main control circuit 4 to output a second level signal to the main control circuit 4, the second output terminal of the optocoupler is grounded, and one end of the second pull-up resistor is connected to the output terminal of the optocoupler, and the other end of the second pull-up resistor is grounded.

[0057] Specifically, the isolation circuit 3 comprises an optocoupler U2 and a second pull-up resistor R7, wherein the optocoupler U2 is a strong and weak electric isolation device, used to realize strong and weak electric isolation, and the second pull-up resistor R7 is connected to the first output terminal of the optocoupler U2 to ensure that the optocoupler can input a high level to the main control circuit 4. The input terminal of the optocoupler U2 is connected to the negative electrode of the first diode D1, and the first level signal output by the comparator U1 can be input into the optocoupler U2. When the first level signal output by the comparator U1 is a low level, the optocoupler cannot be electrified. When the first level signal output by the comparator U1 is a high level, the light-emitting diode end of the optocoupler U2 is electrified and emits light, and the optocoupler U2 outputs a low level through the first output terminal of the optocoupler U2 under the action of the second pull-up resistor R7. At this time, it can be logically judged that the alternating current is near the zero point, and combined with the control logic of the main control circuit 4, the power supply of the alternating current water pump can be turned off near the alternating current zero point.

[0058] In some alternative embodiments, in combination with Figure 3 As shown, the main control circuit 4 includes a control chip, a signal receiving pin of the control chip serving as the first end of the main control circuit 4 to receive the second level signal, and a signal control pin of the control chip serving as the second end of the main control circuit 4 to output a control signal to the water pump control circuit 5 for water pump on-off control.

[0059] In this embodiment, the main control circuit 4 includes a control chip U3, and the control chip U3 includes a ZERO J pin and a PUMP C pin.

[0060] In combination with Figure 2 As shown, in some examples, the control chip U3 first detects whether the AC water pump needs to be turned on, and then detects whether the signal of the ZERO J pin is low. If the signal of the ZERO J pin is low, it means that the AC voltage is near the zero crossing point, and the control signal output by the PUMP C pin is pulled low, and the water pump control circuit 5 is powered on, thereby controlling the AC water pump in the water pump control circuit 5 to turn on. If the signal of the ZERO J pin is high, the signal of the ZERO J pin needs to be continuously detected until it is low, and then the signal of the PUMP C pin is pulled low to control the AC water pump to turn on.

[0061] In some other examples, after the water pump is in the on state, the control chip U3 continues to judge whether the AC water pump needs to be turned off. If the AC water pump needs to be turned off, the signal of the ZERO J pin is detected. If the signal of the ZERO J pin is low, it means that the AC voltage is near the zero crossing point, and the control signal output by the PUMP C pin is pulled low, and the water pump control circuit 5 is powered on, thereby controlling the AC water pump in the water pump control circuit 5 to turn off. If the signal of the ZERO J pin is high, the signal of the ZERO J pin needs to be continuously detected until it is low, and then the signal of the PUMP C pin is pulled low to control the AC water pump to turn off.

[0062] In this embodiment, the ZERO J pin of the control chip U3 is used for signal detection, which can determine whether the AC voltage is near the zero crossing point according to the high and low of the received second level signal. When the second level signal is low, the AC voltage is near the zero crossing point, the control chip U3 pulls the signal of the PUMP C pin low, thereby powering on the water pump control circuit 5 to control the AC water pump to turn on or turn off. Not only can the zero crossing moment of the AC voltage be recognized, but also the water pump can be turned on and turned off near the zero crossing point of the AC voltage, which can reduce the generation of electric arc, reduce electromagnetic interference, and be more conducive to avoiding damage to relays and other devices, thereby improving the safety and reliability of AC water pump control.

[0063] In some alternative embodiments, in combination with Figure 3As shown, the water pump control circuit 5 comprises a relay, a second diode, an AC water pump interface, a resistance-capacitance module, a fifth capacitor and a sixth capacitor.

[0064] The first end of the relay is connected to the second end of the main control circuit 4, the second end of the relay is connected to the charge pump, the third end of the relay is connected to the live wire of the AC power supply, and the fourth end of the relay is connected to the first end of the AC water pump interface.

[0065] The positive electrode of the second diode is connected to the second end of the main control circuit 4 and the first end of the relay, and the negative electrode of the second diode is connected to the second end of the relay and the charge pump.

[0066] The second end of the AC water pump interface is connected to the zero line of the AC power supply, one end of the resistance-capacitance module is connected to the first end of the AC water pump interface, the other end is connected to the second end of the AC water pump interface, the fifth capacitor and the sixth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected to the charge pump.

[0067] Specifically, the water pump control circuit 5 comprises a relay K1, an AC water pump interface JI, a second diode D2, a resistance-capacitance module RC1, a fifth capacitor C5 and a sixth capacitor C6. Among them, the resistance-capacitance module RC1 is used to absorb the electric arc generated in the process of starting or cutting off the water pump power supply, and to protect the contacts of the relay K1 from high voltage impact. The fifth capacitor C5 and the sixth resistor C6 are filter and energy storage capacitors, used to stabilize the voltage at the coil end of the relay K1. The second diode D2 is a freewheeling diode, which provides a freewheeling circuit for the coil of the relay K1 to prevent the MCU from being damaged.

[0068] In this embodiment, when the signal of the ZERO J pin of the control chip U3 is low, the signal of PUMP C will be pulled low, at this time the coil of the relay K1 is powered on and closed, and the AC water pump is turned on. If the signal of the ZERO J pin of the control chip U3 is high, the PUMP C pin outputs high, at this time the AC water pump is continuously disconnected, indicating that the AC voltage has not passed through zero voltage at this time. The program continuously detects whether the signal of the ZERO J pin is low until the signal of the ZERO J pin is low, and the AC voltage has just passed through zero voltage at this time, then the signal of the signal PUMP C is pulled low, at this time the coil of the relay K1 is powered on, and the AC water pump is turned on. Similarly, the principle of controlling the AC water pump to be turned off is the same, and will not be described here.

[0069] In some alternative embodiments, in combination with Figure 3 and Figure 4 As shown, the water pump on-off control circuit further comprises a filter circuit 6, the first end of the filter circuit 6 is connected to the second end of the voltage comparison circuit 2, and the second end of the filter circuit 6 is connected to the first end of the isolation circuit 3, for filtering the first level signal output by the isolation circuit 3.

[0070] Specifically, a filter circuit 6 can be connected between the second end (output end) of the voltage comparison circuit 2 and the isolation circuit 3, and can perform voltage stabilization and filtering processing on the first level signal output by the isolation circuit 3, to provide a stable voltage input for the isolation circuit 3.

[0071] In some examples, the filter circuit 6 can be an RC filter circuit 6, including a seventh capacitor C7 and a sixth resistor R8. One end of the seventh capacitor C7 is connected to one end of the sixth resistor R8 and the input end of the optocoupler U2, and the other end of the seventh capacitor C7 is grounded; the other end of the sixth resistor R8 is connected to the negative electrode of the first diode D1. The voltage output by the comparator U1 is filtered by the seventh capacitor C7 and the sixth resistor R8, and then supplied to the light-emitting diode of the optocoupler U2, to ensure that the optocoupler U2 receives a more stable voltage. In addition, the first diode D1 can also prevent the seventh capacitor C7 from reverse charging the comparator U1, to prevent damage to the comparator U1.

[0072] In summary, in the embodiments of the present application, the AC water pump is turned on and cut off near the AC zero-crossing voltage by identifying the zero-crossing moment of the AC power, which can reduce the generation of electric arc, reduce electromagnetic interference, and is more conducive to avoiding damage to the relay and other devices, and improves the safety and reliability of the AC water pump control. The rectifier bridge UD1 can perform full-wave rectification on the AC power provided by the AC power supply, and input a stable AC comparison voltage to the negative phase end of the comparator U1. The voltage division unit can divide the voltage VCC_C of the external power supply to generate a preset zero voltage V_ZERO as a judgment basis for the AC zero-crossing voltage. The common-mode interference signal in the voltage input to the comparator U1 is filtered by the combination of the positive phase low-pass filter unit and the negative phase low-pass filter unit, and the high-frequency signal is attenuated, which can filter out high-frequency noise, including the high-frequency component in the common-mode interference. The isolation circuit 3 can achieve strong and weak electric isolation, and ensure that the control chip U3 can receive a high-level signal. The control chip U3 can not only identify the zero-crossing moment of the AC power, but also control the relay K1 to be powered near the AC zero-crossing voltage to control the AC water pump to be turned on and cut off, which can reduce the generation of electric arc, reduce electromagnetic interference, and is more conducive to avoiding damage to the relay and other devices, and improves the safety and reliability of the AC water pump control. The filter circuit 6 can perform voltage stabilization and filtering processing on the first level signal output by the isolation circuit 3, to provide a stable voltage input for the isolation circuit 3.

[0073] It should be noted that the models of the electronic devices in the above circuit are not limited to be unique, and different materials can be selected according to actual needs.

[0074] According to another aspect of the embodiments of the present application, the present application provides an air conditioner, which includes the water pump on-off control circuit of any of the above embodiments.

[0075] The air conditioner provided in the embodiment can integrate the water pump opening and closing control circuit in the above embodiments. Based on the water pump opening and closing control circuit, the alternating current zero-crossing voltage detection can be realized, and the power supply of the alternating current water pump can be turned on or cut off near the alternating current zero-crossing voltage, so as to reduce the generation of electric arc and realize the opening and closing control of the alternating current water pump in the air conditioner. The air conditioner provided in the embodiment can realize each embodiment of the above water pump opening and closing control circuit and achieve the corresponding effects. To avoid repetition, details are not repeated here.

[0076] It should be noted that, in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. The electronic components can be connected through electrical connections.

[0077] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A water pump shutoff control circuit, characterized by comprising: The rectifier circuit, the voltage comparison circuit, the isolation circuit, the main control circuit and the water pump control circuit are connected in series. The first end of the rectifier circuit is connected with an AC power supply, and the second end of the rectifier circuit is connected with the first end of the voltage comparison circuit, for rectifying AC power and outputting an AC comparison voltage. The second end of the voltage comparison circuit is connected with the first end of the isolation circuit, for comparing the AC comparison voltage with a preset zero voltage and outputting a first level signal. The second end of the isolation circuit is connected with the first end of the main control circuit, for outputting a second level signal according to the first level signal, and when the second level signal is a low level, the AC power is at a zero voltage. The second end of the main control circuit is connected with the first end of the water pump control circuit, and the second end of the water pump control circuit is connected with the AC power supply, for receiving the second level signal and inputting a control signal to the water pump control circuit to control the water pump when the second level signal is a low level.

2. The water pump shutoff control circuit of claim 1, wherein, The rectifier circuit comprises a rectifier bridge, the first input end of the rectifier bridge is connected with a live wire of the AC power supply, the second input end of the rectifier bridge is connected with a neutral wire of the AC power supply, the first output end of the rectifier bridge is connected with the voltage comparison circuit, and the second output end of the rectifier bridge is grounded.

3. The water pump shutoff control circuit of claim 2, wherein, The voltage comparison circuit comprises a comparator, a voltage dividing unit, a positive phase end low-pass filter unit, a negative phase end low-pass filter unit, a first pull-up resistor, a first diode and a first resistor. The positive phase input end of the comparator is connected with the first end of the positive phase end low-pass filter unit, and the negative phase input end of the comparator is connected with the first end of the negative phase end low-pass filter unit. The second end of the positive phase end low-pass filter unit is connected with the first end of the voltage dividing unit, the second end of the negative phase end low-pass filter unit is connected with the first output end of the rectifier bridge, the second end of the voltage dividing unit is connected with the second output end of the rectifier bridge and grounded, and the third end of the voltage dividing unit is connected with an external power supply. The first diode is connected in series between the output end of the comparator and the isolation circuit, the first end of the first pull-up resistor is connected with the external power supply, the second end of the first pull-up resistor is connected between the output end of the comparator and the anode of the first diode, the first end of the first resistor is connected with the cathode of the first diode, and the second end of the first resistor is grounded.

4. The water pump shutoff control circuit of claim 3, wherein, The voltage dividing unit comprises a second resistor and a third resistor, one end of the second resistor is connected with the external power supply, one end of the third resistor is grounded, and the other ends of the second resistor and the third resistor are commonly connected with the second end of the positive phase end low-pass filter unit, for inputting the preset zero voltage to the positive phase end of the comparator.

5. The water pump shutoff control circuit of claim 4, wherein, The negative phase end low-pass filter unit comprises a fourth resistor, a first capacitor and a second capacitor, one end of the fourth resistor is connected with the first output end of the rectifier bridge, the other end of the fourth resistor is connected with the negative phase input end of the comparator, the first capacitor and the second capacitor are connected in parallel, one end of the parallel connection is grounded, and the other end is connected between the negative phase input end of the comparator and the fourth resistor. The positive terminal low-pass filter unit comprises a fifth resistor, a third capacitor and a fourth capacitor, one end of the fifth resistor is connected to the common end of the second resistor and the third resistor, the other end of the fifth resistor is connected to the positive input terminal of the comparator, the third capacitor and the fourth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected between the positive input terminal of the comparator and the fifth resistor.

6. The water pump shutoff control circuit of claim 3, wherein, The isolation circuit comprises a photocoupler and a second pull-up resistor. The input terminal of the photocoupler is connected to the negative electrode of the first diode, the first output terminal of the photocoupler is connected to the first end of the master control circuit to output the second level signal to the master control circuit, the second output terminal of the photocoupler is grounded, and one end of the second pull-up resistor is connected to the output terminal of the photocoupler, and the other end of the second pull-up resistor is grounded.

7. The water pump shutoff control circuit of claim 1, wherein, The master control circuit comprises a control chip, a signal receiving pin of the control chip serves as the first end of the master control circuit to receive the second level signal, and a signal control pin of the control chip serves as the second end of the master control circuit to output a control signal to the water pump control circuit for water pump on-off control.

8. The water pump shutoff control circuit of any one of claims 1 to 7, wherein, The water pump control circuit comprises a relay, a second diode, an alternating current water pump interface, a resistance-capacitance module, a fifth capacitor and a sixth capacitor. The first end of the relay is connected to the second end of the master control circuit, the second end of the relay is connected to a charge pump, the third end of the relay is connected to the live wire of the alternating current power supply, and the fourth end of the relay is connected to the first end of the alternating current water pump interface. The positive electrode of the second diode is connected to the second end of the master control circuit and the first end of the relay, and the negative electrode of the second diode is connected to the second end of the relay and the charge pump. The second end of the alternating current water pump interface is connected to the zero line of the alternating current power supply, one end of the resistance-capacitance module is connected to the first end of the alternating current water pump interface, the other end of the resistance-capacitance module is connected to the second end of the alternating current water pump interface, the fifth capacitor and the sixth capacitor are connected in parallel, and one end of the parallel connection is grounded, and the other end is connected to the charge pump.

9. The water pump shutoff control circuit of any one of claims 1 to 7, wherein, The filter circuit further comprises a first end connected to the second end of the voltage comparison circuit and a second end connected to the first end of the isolation circuit, for filtering the first level signal output by the isolation circuit.

10. An air conditioner characterized by comprising: The air conditioner comprises the water pump on-off control circuit according to any one of claims 1 to 9.

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