Water pump on-off control circuit and air conditioner

Abstract

The invention 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 to a water pump on-off control circuit and an air conditioner. Background Art

[0002] In the current air conditioner system, the control method of the AC water pump is relatively basic and direct, mainly relying on an electromagnetic relay as the core control component. When it is necessary to start the water pump to promote the coolant circulation of the air conditioner system, the control system sends a signal to the electromagnetic relay, causing the contacts inside it to close, thereby connecting the AC power supply to the water pump motor, and the water pump starts to work immediately. On the contrary, when the system detects that further cooling is not required or the preset conditions are reached and the water pump needs to be stopped, the control system sends another instruction to the relay, causing its contacts to open and cutting off the power supply to the water pump, and the water pump stops running immediately.

[0003] However, this control method faces a problem that cannot be ignored in practical applications: at the moment when the power supply is closed and cut off, the AC water pump, as a typical inductive load, will generate an instantaneous high voltage in its internal inductance coil, which is often accompanied by a huge electric arc. The electric arc will not only wear the relay contacts and shorten their service life, but also release strong electromagnetic interference. This interference signal may spread along the power line, affecting the stability and reliability of the entire air conditioner control system, and even interfering with other electronic devices connected thereto, such as sensors, controllers, etc., resulting in malfunction or performance degradation. Even more seriously, the generation of the electric arc may also cause safety hazards, such as causing a short circuit in the circuit and increasing the fire risk.

[0004] It can be seen that in the control of the AC water pump of the air conditioner, how to reduce the generation of the electric arc, reduce or avoid damage to devices such as relays, and improve the safety and reliability of the AC water pump control becomes particularly important. Summary of the Invention

[0005] The present application provides a water pump on-off control circuit and an air conditioner to solve the above technical problems in the existing control of the AC water pump of the air conditioner, where the generation of a large electric arc causes damage to devices such as relays and there is a low safety and reliability.

[0006] According to one aspect of the embodiments of the present application, the present application provides a water pump switching control circuit, including a rectification circuit, a voltage comparison circuit, an isolation circuit, a main control circuit and a water pump control circuit; the first end of the rectification circuit is connected to an AC power supply, and the second end of the rectification circuit is connected to the first end of the voltage comparison circuit, for rectifying the alternating current and outputting an AC comparison voltage; the second end of the voltage comparison circuit is connected to the first end of the isolation circuit, for comparing according to the AC comparison voltage and a preset zero-crossing voltage and outputting a first level signal; the second end of the isolation circuit is connected to the first end of the main control circuit, for outputting a second level signal according to the first level signal, when the second level signal is a low level, the alternating current passes through the zero-crossing voltage; the second end of the main control circuit is connected to the first end of the water pump control circuit, and the second end of the water pump control circuit is connected to the AC power supply, for receiving the second level signal and inputting a control signal to the water pump control circuit to control the switching of the water pump when the second level signal is a low level.

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

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

[0009] Optionally, 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 positive-phase terminal low-pass filtering unit, for inputting the preset zero-crossing voltage to the positive-phase terminal of the comparator.

[0010] Optionally, the negative-phase terminal low-pass filtering unit includes a fourth resistor, a first capacitor, and a second capacitor. One end of the fourth resistor is connected to the first output terminal of the rectifier bridge, and the other end of the fourth resistor is connected to the negative-phase input terminal 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 terminal of the comparator and the fourth resistor. The positive-phase terminal low-pass filtering unit includes a fifth resistor, a third capacitor, and a fourth capacitor. One end of the fifth resistor is connected to the common terminal of the second resistor and the third resistor, and the other end of the fifth resistor is connected to the positive-phase 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-phase input terminal of the comparator and the fifth resistor.

[0011] Optionally, the isolation circuit includes: an optocoupler and a second pull-up resistor; 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 to output the second level signal to the main control circuit, the second output terminal of the optocoupler is grounded, 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.

[0012] Optionally, the main control circuit includes a control chip. The signal receiving pin of the control chip serves as the first terminal of the main control circuit to receive the second level signal, and the signal control pin of the control chip serves as the second terminal of the main control circuit to output a control signal to the water pump control circuit for controlling the on / off of the water pump.

[0013] Optionally, the water pump control circuit includes: a relay, a second diode, an AC water pump interface, a resistor-capacitor module, a fifth capacitor, and a sixth capacitor; the first terminal of the relay is connected to the second terminal of the main control circuit, the second terminal of the relay is connected to the charge pump, the third terminal of the relay is connected to the live wire of the AC power supply, and the fourth terminal of the relay is connected to the first terminal of the AC water pump interface; the positive electrode of the second diode is connected to the second terminal of the main control circuit and the first terminal of the relay, and the negative electrode of the second diode is connected to the second terminal of the relay and the charge pump; the second terminal of the AC water pump interface is connected to the neutral wire of the AC power supply, one end of the resistor-capacitor module is connected to the first terminal of the AC water pump interface, the other end is connected to the second terminal 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.

[0014] Optionally, a filter circuit is further included. The first end of the filter circuit is connected to the second end of the voltage comparison circuit, and the second end of the filter circuit is connected to the first end of the isolation circuit, and is configured to filter 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, and the air conditioner includes the above-mentioned water pump on-off control circuit.

[0016] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the related technologies:

[0017] The present application provides a water pump on-off control circuit. By inputting an AC comparison voltage and a preset zero-point voltage to a comparator for comparison, when the first level signal output by the voltage comparison circuit is at a high level, it indicates that the alternating current is near the zero-point voltage at this time. Further, the isolation circuit is used to isolate the strong and weak electricity and output a second level signal to the main control circuit. The second level signal is input to the main control circuit as a judgment reference for the alternating current passing through the zero-point voltage. When the second level signal received by the main control circuit is at a low level, it is judged that the alternating current is near the zero-point voltage. At this time, the voltage in the circuit is very low, close to zero. When the alternating current passes through the zero-point voltage, the main control circuit outputs a control signal to the water pump control circuit to control the on-off of the AC water pump. Then, the electric field strength between the power electrodes of the AC water pump will be very small, which is not enough to ionize gas molecules or atoms, so arcs will not be 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 alternating current passes through the zero-point voltage, but also control the on-off of the water pump based on the main control circuit when the alternating current passes through the zero-point voltage. This can reduce the generation of arcs, thereby reducing electromagnetic interference, and is more conducive to avoiding damage to devices such as relays and improving the safety and reliability of controlling the AC water pump. Description of the Drawings

[0018] The drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or the related technologies. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic diagram of the modules of an optional water pump on-off control circuit provided according to the embodiments of the present application;

[0021] Figure 2Schematic diagram of the control process of an optional water pump on-off control circuit provided according to an embodiment of the present application;

[0022] Figure 3 Schematic diagram of an optional water pump on-off control circuit provided according to an embodiment of the present application;

[0023] Figure 4 Schematic diagram of modules of another optional water pump on-off control circuit provided according to an embodiment of the present application.

[0024] Description of the drawings: 1. Rectifier circuit, 2. Voltage comparison circuit, 3. Isolation circuit, 4. Main control circuit, 5. Water pump control circuit, 6. Filter circuit. Detailed implementation manners

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0026] The principle and structure of the present application will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] To solve the above technical problem that in the existing control of the AC water pump of an air conditioner, large arcs are generated, causing damage to devices such as relays, and there is low safety and reliability.

[0028] In response to the above problem, the design idea of the present application is to compare an AC comparison voltage and a preset zero-point voltage input to a comparator. When the first level signal output by the voltage comparison circuit is a high level, it indicates that the alternating current is near the zero-point voltage at this time. Further, the isolation circuit is used to isolate the strong and weak currents and output a second level signal to the main control circuit. When the second level signal received by the main control circuit is a low level, the alternating current is near the zero-point 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 on-off of the AC water pump when the alternating current passes through the zero-point voltage. Then, the electric field strength between the power electrodes of the AC water pump will be very small, not enough to ionize gas molecules or atoms, so arcs will not be formed or weakened. It can not only determine whether the alternating current passes through the zero-point voltage but also control the on-off of the water pump when the alternating current passes through the zero-point voltage. This can reduce the generation of arcs, thereby reducing electromagnetic interference, and is more conducive to avoiding damage to devices such as relays and improving the safety and reliability of the control of the AC water pump.

[0029] In an embodiment of the present application, a water pump opening and closing control circuit provided includes a rectification 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 rectification circuit 1 is connected to an AC power supply, and the second end of the rectification circuit 1 is connected to the first end of the voltage comparison circuit 2, which is used to rectify the alternating current and output 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, which is used to compare the AC comparison voltage with a preset zero - point voltage and output 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, which is used to output a second - level signal according to the first - level signal. When the second - level signal is at a low level, it indicates that the alternating current is at the zero - point 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. It is used to receive the second - level signal and input a control signal to the water pump control circuit 5 for water pump opening and closing control when the second - level signal is at a low level.

[0034] Specifically, the above - mentioned rectification circuit 1 can include full - wave rectification, half - wave rectification, etc. Through the rectification circuit 1, the alternating current input from the input AC power supply can be rectified to input an AC comparison voltage to the voltage comparison circuit 2. Among them, the AC comparison voltage can be used as a basic signal for zero - point voltage judgment, and specifically, it can be a rectified AC voltage.

[0035] The above - mentioned voltage comparison circuit 2 has two inputs, including a positive - phase terminal input and a negative - phase terminal input. The negative - phase terminal inputs the AC comparison voltage, and the positive - phase terminal inputs a preset zero - point voltage. Then, the voltage comparison circuit 2 compares the two input voltages to output a first - level signal. Among them, the specific voltage value of the preset zero - point 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 - point voltage is slightly larger than 0V. For example, the specific voltage value of the preset zero - point voltage is 0.2V. Among them, 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 - point 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 - point 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 alternating current is near the preset zero - point voltage at this time.

[0036] The above isolation circuit 3 is used to achieve the isolation between strong and weak electricity, and output a second level signal according to the first level signal. When the first level signal is high, the second level signal is low, and at this time it is near the zero-crossing voltage of the alternating current; when the first level signal is low, the second level signal is high, and at this time the alternating current is not near the zero-crossing voltage. The above main control circuit 4 is used to output a control signal when the second level signal is low, and the above 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 received 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, indicating that the alternating current has not yet reached the preset zero-crossing voltage. The control signal input by the main control circuit 5 to the water pump control circuit 5 is a low level signal, and at this time the water pump control circuit 5 is not powered, and the AC water pump remains off. When the first level signal is a high level signal, the second level signal output by the isolation circuit 3 is low. The main control circuit 4 receives the low level signal, indicating that the alternating current just passes near the zero-crossing voltage. The control signal input by the main control circuit 4 to the water pump control circuit 5 is a low level signal, and at this time the water pump control circuit 5 is powered, and the AC water pump is turned on.

[0038] In some examples, in combination with Figure 2 As shown, before performing the water pump on / off control, the main control circuit 4 can also detect the state of the AC water pump, determine whether the state of the AC water pump has been turned on, and determine whether it is necessary to turn on or off the AC water pump. On the premise of detecting that it is necessary to turn on / off the AC water pump, then perform the water pump on / off control based on the water pump on / off control circuit.

[0039] In the embodiment of the present application, an alternating current comparison voltage and a preset zero-point voltage are input to a comparator for comparison. When the first level signal output by the voltage comparison circuit 2 is a high level, it indicates that the alternating current is near the zero-point voltage at this time. Further, the isolation circuit 3 is used to isolate the strong and weak currents and output a second level signal to the main control circuit 4. The second level signal is used as a judgment reference for the alternating current passing through the zero-point voltage and is input to the main control circuit 4. When the second level signal received by the main control circuit 4 is a low level, it is judged that the alternating current is near the zero-point voltage. At this time, the voltage in the circuit is very low, approaching zero. The main control circuit 4 outputs a control signal to the water pump control circuit 5 to control the on / off of the AC water pump when the alternating current passes through the zero-point voltage. Then, the electric field strength between the power electrodes of the AC water pump will be very small, which is not sufficient to ionize gas molecules or atoms. Therefore, an arc will not be formed or weakened. It can be seen that based on the voltage comparison circuit 2 and the isolation circuit 3, the present application can not only determine whether the alternating current passes through the zero-point voltage, but also control the on / off of the water pump based on the main control circuit 4 when the alternating current passes through the zero-point voltage. This can reduce the generation of arcs, thereby reducing electromagnetic interference, and is more conducive to avoiding damage to devices such as relays and improving the safety and reliability of controlling the AC water pump.

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

[0041] Specifically, Figure 3 In, the rectifier bridge is UD1. The rectifier bridge UD1 can be a full-wave rectifier bridge. Connect the first input terminal of the rectifier bridge UD1 to the live wire (AC_L) of the AC power supply and the second input terminal to the neutral wire (AC_N) of the AC power supply. The negative half-cycle voltage of the alternating current is converted into a positive half-cycle voltage through the rectifier bridge UD1 to achieve full-wave rectification of the alternating current provided by the AC power supply, and a stable alternating current comparison voltage is input to the negative phase terminal of the voltage comparison circuit 2 through the first output terminal.

[0042] In some alternative embodiments, in combination with Figure 3 As shown, the voltage comparison circuit 2 includes: a comparator, a voltage dividing unit, a positive-phase terminal low-pass filtering unit, a negative-phase terminal low-pass filtering unit, a first pull-up resistor, a first diode, and a first resistor;

[0043] The positive-phase input terminal of the comparator is connected to the first end of the positive-phase terminal low-pass filtering unit, and the negative-phase input terminal of the comparator is connected to the first end of the negative-phase terminal low-pass filtering unit;

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

[0045] The first diode is connected in series between the output terminal 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 terminal of the comparator and the positive electrode of the first diode. The first end of the first resistor is connected to the negative electrode of the first diode, and the second end of the first resistor is grounded.

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

[0047] Further, connect the positive-phase input terminal (+) of the comparator U1 to the first terminal of the positive-phase terminal low-pass filter unit, the negative-phase input terminal (-) to the first terminal of the negative-phase terminal low-pass filter unit, the second terminal of the positive-phase terminal low-pass filter unit to the first terminal of the voltage dividing unit, and the second terminal of the negative-phase terminal low-pass filter unit to the first output terminal of the rectifier bridge UD1. Divide the VCC_C provided by the external power supply through the voltage dividing unit to obtain a preset zero-point voltage V_ZERO and input it to the positive-phase terminal of the comparator U1. And input an AC comparison voltage to the negative-phase terminal of the comparator U1 through the first output terminal of the rectifier bridge UD1. Filter the common-mode interference signal in the voltage at the input terminal of the comparator U1 through the combination of the positive-phase terminal low-pass filter unit and the negative-phase terminal low-pass filter unit, and finally perform voltage comparison through the comparator U1 to output a first-level signal.

[0048] Furthermore, by utilizing the unidirectional conductivity of the first diode D2, the direction of voltage signal transmission can be determined. Not only can the first level signal be input into the isolation circuit 3 along the transmission direction, but also the protection of the comparator U2 can be achieved to avoid reverse charging. At the same time, the first pull-up resistor R1 and the first resistor R2 can form a voltage division to provide a suitable operating voltage for the isolation circuit 3. In addition, since the output of the comparator U1 is an open-drain output and can only output a low level, by connecting the first pull-up resistor R1 to the output terminal of the comparator U1 and inputting VCC_C provided by an external power supply at the other end, it can be determined that the output level of the comparator U1 is a high level, ensuring that the comparator U1 can output both a low level and, with the assistance of the first pull-up resistor R1, achieve a high-level output. Moreover, when the high level is output, the alternating current passes through the zero-crossing voltage simultaneously.

[0049] In some alternative embodiments, as shown in Figure 3 the voltage division unit includes a second resistor and a third resistor. One end of the second resistor is connected to an 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 positive-phase low-pass filter unit for inputting a preset zero-crossing voltage to the positive phase of the comparator.

[0050] Specifically, the voltage division unit can be composed of two resistors, or a multi-resistor voltage division network composed of more than two resistors, or a variable resistor can also be used, such as a three-terminal potentiometer. The value of the preset zero-crossing voltage can be set according to the resistance values in the voltage division unit. In this embodiment, the voltage division 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 where the second resistor R3 and the third resistor R4 are commonly connected is connected to the positive-phase low-pass filter unit and then connected to the positive phase of the comparator U1. By dividing the voltage of VCC_C through the second resistor R3 and the third resistor R4, the obtained divided voltage is used as the preset zero-crossing voltage V_ZERO, and V_ZERO = VCC_C / (R7 + R8) × R8. Thus, the preset zero-crossing voltage V_ZERO obtained by voltage division is input to the positive phase of the comparator U1 as the basis for judging the alternating current zero-crossing voltage.

[0051] In some alternative embodiments, as shown in Figure 3 the negative-phase 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 terminal of the rectifier bridge, the other end of the fourth resistor is connected to the negative-phase input terminal 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 terminal of the comparator and the fourth resistor;

[0052] The positive-phase terminal low-pass filtering unit includes a fifth resistor, a third capacitor, and a fourth capacitor. One end of the fifth resistor is connected to the common terminal of the second resistor and the third resistor, and the other end of the fifth resistor is connected to the positive-phase 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-phase input terminal of the comparator and the fifth resistor.

[0053] Specifically, the structure of the negative-phase terminal low-pass filtering unit can be kept consistent with that of the positive-phase terminal low-pass filtering unit. The negative-phase terminal low-pass filtering unit is connected to the negative-phase terminal of the comparator U1, and the positive-phase terminal low-pass filtering unit is connected to the positive-phase terminal of the comparator U1, jointly filtering the common-mode interference signals of the voltage at the input terminal of the comparator U1. And by allowing low-frequency signals to pass through the low-pass filter and attenuating high-frequency signals, adding a low-pass filter at the input terminal of the comparator U1 can filter out high-frequency noise, including the high-frequency components in the common-mode interference.

[0054] Furthermore, the negative-phase terminal low-pass filtering unit includes a fourth resistor R5, a first capacitor C1, and a second capacitor C2; the positive-phase terminal low-pass filtering unit includes a fifth resistor R6, a third capacitor C3, and a fourth capacitor C4. Among them, connecting two capacitors in parallel can increase the total capacitance value, thereby reducing the cut-off frequency of the low-pass filter, more effectively filtering out high-frequency signals, and ensuring that the comparator U1 receives a more stable and accurate AC comparison voltage and the preset zero-point voltage.

[0055] In some optional embodiments, as shown in Figure 3 the isolation circuit 3 includes: 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, 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 includes an optocoupler U2 and a second pull-up resistor R7. Among them, the optocoupler U2 is a device for isolating strong electricity and weak electricity, used to achieve the isolation of strong and weak electricity, and a 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. Connect the input terminal of the optocoupler U2 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 at a low level, the optocoupler is not powered on. When the first-level signal output by the comparator U1 is at a high level, the light-emitting diode terminal of the optocoupler U2 is powered on and emits light. Under the action of the second pull-up resistor R7, the optocoupler U2 outputs a low level through its first output terminal. At this time, logically, it can be judged that the alternating current is near the zero point. Combining with the control logic of the main control circuit 4, the power supply of the AC water pump can be switched on and off near the AC zero point.

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

[0059] Among them, 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 it is low, it means that the AC voltage passes through the zero point at this time, and then the control signal output by the PUMP_C pin is pulled low, and the water pump control circuit 5 is powered on, so as to control the AC water pump in the water pump control circuit 5 to turn on; if the signal of the measured ZERO_J pin is high, it is necessary to continuously detect the signal of the ZERO_J pin until it is low, and then pull low the signal of the PUMP_C pin 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 will continue to judge whether the AC water pump needs to be turned off. If the AC water pump needs to be turned off, it detects whether the signal of the ZERO_J pin is low. If it is low, it means that the AC voltage passes through the zero point at this time, and then the control signal output by the PUMP_C pin is pulled low. At this time, the water pump control circuit 5 is powered on, so as to control the AC water pump in the water pump control circuit 5 to be disconnected; if the signal of the ZERO_J pin is high, it is necessary to continuously detect the signal of the ZERO_J pin until it is low, and then pull low the signal of the PUMP_C pin to control the AC water pump to be disconnected.

[0062] In this embodiment, by detecting the signal through the ZERO_J pin of the control chip U3, it is possible to judge whether the AC voltage is near the zero crossing point according to the level of the received second-level signal. When the second-level signal is low, the AC voltage is near the zero crossing point, and the control chip U3 pulls low the signal of the PUMP_C pin, so that the water pump control circuit 5 is powered on, and the AC water pump is controlled to turn on or off. It can not only identify the zero crossing moment of the alternating current but also turn on and cut off the water pump near the AC zero crossing voltage, which can reduce the generation of electric arcs, reduce electromagnetic interference, and is more conducive to avoiding damage to equipment such as relays, improving the safety and reliability of the control of the AC water pump.

[0063] In some optional embodiments, in combination with Figure 3As shown, the water pump control circuit 5 includes: a relay, a second diode, an AC water pump interface, a resistor-capacitor 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 pole 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 pole 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 neutral wire of the AC power supply. One end of the resistor-capacitor module is connected to the first end of the AC water pump interface, and 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 includes a relay K1, an AC water pump interface JI, a second diode D2, a resistor-capacitor module RC1, a fifth capacitor C5, and a sixth capacitor C6. Among them, the resistor-capacitor module RC1 is used to absorb the arc generated during the opening or closing of the water pump power supply, protecting 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, used to provide a freewheeling circuit for the coil of the relay K1 to prevent damage to the MCU.

[0068] In this embodiment, when the signal of the ZERO_J pin of the control chip U3 is at a low level, the signal of PUMP_C will be pulled low. At this time, the coil of the relay K1 is energized and closed, and the AC water pump is turned on. If the signal of the ZERO_J pin of the control chip U3 is at a high level, the PUMP_C pin outputs a high level. At this time, the AC water pump remains disconnected, indicating that the AC power has not passed through the zero-crossing voltage yet. The program continuously detects whether the signal of the ZERO_J pin is at a low level until the signal of the ZERO_J pin is at a low level and the AC power just passes through the zero-crossing voltage, then the signal of PUMP_C is pulled low. At this time, the coil of the relay K1 is energized, and the AC water pump is turned on. Similarly, the principle of controlling the AC water pump to turn off is the same and will not be elaborated here.

[0069] In some optional embodiments, in combination with Figure 3 and Figure 4 as shown, the water pump on-off control circuit further includes 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, used to filter the first-level signal output by the isolation circuit 3.

[0070] Specifically, a filter circuit 6 can be connected between the second terminal (output terminal) of the voltage comparison circuit 2 and the isolation circuit 3, which can perform voltage stabilization and filtering 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 above 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 terminal 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 to supply power 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 charging the comparator U1 in the reverse direction and prevent the comparator U1 from being damaged.

[0072] In summary, in the embodiment of the present application, by identifying the zero-crossing moment of the alternating current and turning on and off the AC water pump near the zero-crossing voltage of the alternating current, the generation of electric arcs can be reduced, electromagnetic interference can be reduced, it is more beneficial to avoid damage to devices such as relays, and the safety and reliability of controlling the AC water pump are improved. Through the rectifier bridge UD1, the alternating current provided by the AC power supply can be full-wave rectified, and a stable AC comparison voltage can be input to the negative phase terminal of the comparator U1. Through the voltage dividing unit, a preset zero-point voltage V_ZERO can be generated by voltage division according to the external power supply voltage VCC_C as the judgment basis for the zero-crossing voltage of the alternating current. Through the combination of the positive-phase end low-pass filter unit and the negative-phase end low-pass filter unit, the common-mode interference signals in the voltage at the input terminal of the comparator U1 are filtered, and high-frequency signals are attenuated, and high-frequency noise, including high-frequency components in the common-mode interference, can be filtered out. Through the isolation circuit 3, strong and weak electricity isolation can be achieved, and it is ensured that the control chip U3 can receive a high-level signal. Through the control chip U3, not only can the zero-crossing moment of the alternating current be identified, but also near the zero-crossing voltage of the alternating current, the relay K1 can be controlled to be powered on to control the opening and closing of the AC water pump, which can reduce the generation of electric arcs, reduce electromagnetic interference, is more beneficial to avoid damage to devices such as relays, and improves the safety and reliability of controlling the AC water pump. Through the filter circuit 6, the first-level signal output by the isolation circuit 3 can be subjected to voltage stabilization and filtering to provide a stable voltage input for the isolation circuit 3.

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

[0074] According to another aspect of the embodiment of the present application, the present application provides an air conditioner, and the air conditioner includes the water pump opening and closing control circuit of any one of the above embodiments.

[0075] The air conditioner provided in this embodiment may integrate the water pump on-off control circuit in the above embodiment. Based on the water pump on-off control circuit, the zero-crossing voltage detection of alternating current can be realized, and the power supply of the AC water pump can be turned on or off near the zero-crossing voltage of the alternating current, so as to reduce the generation of electric arcs and realize the on-off control of the AC water pump in the air conditioner. Based on the air conditioner provided in this embodiment, each embodiment in the above water pump on-off control circuit can be realized and the corresponding effects can be achieved. To avoid repetition, they will not be elaborated one by one here.

[0076] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the element. Among them, the electronic components can be connected by electrical connection means.

[0077] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious 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 rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A water pump disconnection control circuit, characterized in that: It includes a rectifier circuit, a voltage comparison circuit, an isolation circuit, a main control circuit and a water pump control circuit; The first end of the rectifier circuit is connected to an AC power source, and the second end of the rectifier circuit is connected to a first end of the voltage comparison circuit, for rectifying the AC power and outputting an AC comparison voltage; The second end of the voltage comparison circuit is connected to the first end of the isolation circuit, and is used to compare the AC comparison voltage and the preset zero-point voltage, and output a first level signal; The second end of the isolation circuit is connected to the first end of the main control circuit, and is used to output a second level signal according to the first level signal, and when the second level signal is at a low level, the AC power passes through a zero voltage; The second end of the main control circuit is connected to the first end of the water pump control circuit, and the second end of the water pump control circuit is connected to the AC power supply, for receiving the second level signal, and inputting a control signal to the water pump control circuit to perform water pump on-off control when the second level signal is at a low level.

2. The water pump disconnection control circuit according to claim 1, characterized in that: The rectifier circuit includes a rectifier bridge, a first input end of the rectifier bridge is connected to the live wire of the AC power supply, a second input end of the rectifier bridge is connected to the neutral wire of the AC power supply, a first output end of the rectifier bridge is connected to the voltage comparison circuit, and a second output end of the rectifier bridge is grounded.

3. The water pump disconnection control circuit according to claim 2 is characterized in that: The voltage comparison circuit comprises: a comparator, a voltage dividing unit, a positive-end low-pass filter unit, a negative-end low-pass filter unit, a first pull-up resistor, a first diode and a first resistor; The positive phase input terminal of the comparator is connected to the first terminal of the positive phase low pass filter unit, and the negative phase input terminal of the comparator is connected to the first terminal of the negative phase low pass filter unit; The second end of the positive phase low-pass filter unit is connected to the first end of the voltage divider unit, the second end of the negative phase low-pass filter unit is connected to the first output end of the rectifier bridge, the second end of the voltage divider unit is connected to the second output end of the rectifier bridge and grounded, and the third end of the voltage divider unit is connected to 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 to an external power supply, the second end of the first pull-up resistor is connected between the output end of the comparator and the positive electrode of the first diode, the first end of the first resistor is connected to the negative electrode of the first diode, and the second end of the first resistor is grounded.

4. The water pump on-off control circuit according to claim 3, characterized in that: The voltage divider unit includes a second resistor and a third resistor, one end of the second resistor is connected to an 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 positive phase low-pass filter unit, for inputting the preset zero point voltage to the positive phase end of the comparator.

5. The water pump disconnection control circuit according to claim 4, characterized in that: The negative phase 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, 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 positive phase end low-pass filter unit includes 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 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 phase input terminal of the comparator and the fifth resistor.

6. The water pump on-off control circuit according to claim 3, characterized in that: The isolation circuit includes: an optical coupler and a second pull-up resistor; The input end of the optocoupler is connected to the cathode of the first diode, the first output end of the optocoupler is connected to the first end of the main control circuit to output the second level signal to the main control circuit, the second output end of the optocoupler is grounded, 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.

7. The water pump on-off control circuit according to claim 1, characterized in that: The main control circuit includes a control chip, a signal receiving pin of the control chip serves as the first end of the main control circuit to receive the second level signal, and a signal control pin of the control chip serves as the second end of the main control circuit to output a control signal to the water pump control circuit to control the water pump on and off.

8. The water pump disconnection control circuit according to any one of claims 1 to 7, characterized in that: The water pump control circuit includes: a relay, a second diode, an AC 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 main control circuit, 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; The anode of the second diode is connected to the second end of the main control circuit and the first end of the relay, and the cathode of the second diode is connected to the second end of the relay and the charge pump; The second end of the AC water pump interface is connected to the neutral line of the AC power supply, one end of the resistor-capacitor module is connected to the first end of the AC water pump interface, and 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.

9. The water pump disconnection control circuit according to any one of claims 1 to 7, characterized in that: It also includes a filter circuit, a first end of the filter circuit is connected to the second end of the voltage comparison circuit, and the second end of the filter circuit is 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 in that: The air conditioner comprises the water pump on-off control circuit according to any one of claims 1 to 9.

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