Zero-crossing signal protection circuit and protection system for relay of clothes airing machine

Abstract

The utility model discloses a clothes airing machine relay zero-crossing signal protection circuit and protection system, and the circuit comprises a rectification module, a voltage stabilization module, a charging and discharging module, and an optocoupler module. The rectifier module is used for accessing an alternating current power supply, rectifying and outputting direct current, the voltage stabilizing module is connected with the output end of the rectifier module, the optocoupler module is used for accessing a main control chip of the clothes airing machine, and the charging and discharging module is connected between the voltage stabilizing module and the optocoupler module in parallel; the voltage stabilizing module comprises a first resistor, a second resistor, a third resistor and a voltage stabilizing diode; the charging and discharging module comprises a diode, an electrolytic capacitor and a P-MOS tube; the circuit has the advantages that the circuit power consumption is reduced through the first resistor, and the protection response speed is increased; the on-off of the photoelectric coupler is controlled through a charging and discharging mechanism in which the P-MOS tube and the electrolytic capacitor are matched with each other, so that the power consumption is further reduced, the protection response speed is improved, and the occurrence of false triggering is reduced.

Description

Technical Field

[0001] The utility model relates to the field of electric clothes dryers, in particular to a circuit and a protection system for zero-crossing signal protection of a relay used in a clothes dryer, which can protect the relay of the clothes dryer and related components electrically connected to the relay against zero-crossing signals. Background Art

[0002] The alternating current used in daily life has its voltage alternating positively and negatively according to the periodic law of the sine function. There are two instants when the instantaneous voltage amplitude is zero in each cycle, that is, two instants of positive and negative alternation. At this time, a zero-crossing signal will appear.

[0003] As Figure 1 shown is the circuit system block diagram of the main body of an electric clothes dryer. When the clothes dryer is running normally, due to the appearance of the zero-crossing signal of the alternating current, it is very likely that a zero-crossing signal will also appear in the circuit system of the main body, resulting in mis-triggering of the relay, and the corresponding contact switch will instantaneously close or instantaneously open. Although there is a certain probability, due to the high frequency of the alternating current (50HZ in China), when accumulated, the number of mis-triggerings of the relay is too many, which will damage the relay. There may also be a situation where the contact switch is always open and cannot close, and even the running clothes dryer will suddenly stop, and the drying module, lifting module, disinfection module, etc. of the clothes dryer will stop unexpectedly, thereby damaging the relevant modules or the corresponding hardware mechanisms.

[0004] To avoid the above negative impacts of the zero-crossing signal, some existing clothes dryers have adopted zero-crossing signal protection circuits. For example, a zero-crossing protection circuit applied to an electric clothes dryer disclosed in the utility model patent with the authorization announcement number CN205583666U. The zero-crossing detection module includes a half-wave rectification module and an opto-coupling module. The AC power supply U of the load is rectified by the half-wave rectification module and then sent to the opto-coupling module, and the opto-coupling module outputs a zero-crossing detection signal UA. The load AC supply power U is connected between L and N. The half-wave rectification module includes a diode D1 for half-wave rectifying the power supply U. The opto-coupling module includes an opto-coupler U1, opto-coupler current-limiting protection devices R1, R2, a pull-up resistor R3 at port A, and a resistor R4 and a capacitor C1 for filtering.

[0005] The zero-crossing signal protection circuits in the prior art have at least the following technical problems: 1. Using half-wave rectification only utilizes half of the cycle of the alternating current, which may lead to low voltage utilization rate, thus affecting the efficiency of the circuit and the power demand of the load; 2. The opto-coupling pre-circuit has high power consumption, which not only affects the module response speed and filtering effect, but also affects the accuracy of zero-crossing detection and the stability of the circuit. Summary of the Utility Model

[0006] In view of the problems existing in the zero-crossing signal protection circuit in the prior art, such as large power consumption, which affects the response speed and filtering effect of the module, as well as the accuracy of zero-crossing detection and the stability of the circuit, the technical problem to be solved by the present utility model is to provide a zero-crossing signal protection circuit for a clothes dryer relay, which adopts small current control to achieve low power consumption, fast response, and low false triggering rate for the zero-crossing signal protection of the clothes dryer relay.

[0007] The technical solution adopted by the present utility model to solve the above technical problems is as follows: A zero-crossing signal protection circuit for a clothes dryer relay, comprising a rectification module, a voltage stabilization module, a charge and discharge module, and an optocoupler module;

[0008] The rectification module is used to connect to an AC power supply, rectify and output direct current. The voltage stabilization module is connected to the output end of the rectification module. The optocoupler module is used to connect to the main control chip of the clothes dryer. The charge and discharge module is connected in parallel between the voltage stabilization module and the optocoupler module;

[0009] The voltage stabilization module includes a first resistor, a second resistor, a third resistor, and a voltage stabilizing diode. One end of the first resistor is connected to the positive pole of the output end of the rectification module, and the other end of the first resistor is connected to the negative pole of the voltage stabilizing diode. The positive pole of the voltage stabilizing diode is connected to the negative pole of the output end of the rectification module. The second resistor and the third resistor are connected in series. The other end of the second resistor is connected to the node between the first resistor and the negative pole of the voltage stabilizing diode. The other end of the third resistor is connected to the negative pole of the output end of the rectification module. The resistance value of the first resistor is greater than the sum of the resistance values of the second resistor and the third resistor;

[0010] The charge and discharge module includes a diode, an electrolytic capacitor, and a P-MOS transistor. The positive pole of the diode is connected to the negative pole of the voltage stabilizing diode, and the negative pole of the diode is connected to the source electrode of the P-MOS transistor. The positive pole of the electrolytic capacitor is connected to the node between the negative pole of the diode and the source electrode of the P-MOS transistor, and the negative pole of the electrolytic capacitor is connected to the positive pole of the voltage stabilizing diode. The gate electrode of the P-MOS transistor is connected to the node between the negative pole of the voltage stabilizing diode and the positive pole of the diode;

[0011] The optocoupler module includes an optocoupler. The positive pole of the emitter of the optocoupler is connected to the drain electrode of the P-MOS transistor. The negative pole of the emitter of the optocoupler is connected to the node between the positive pole of the voltage stabilizing diode and the negative pole of the electrolytic capacitor. The E pole of the receiving end of the optocoupler is grounded, and the C pole of the receiving end of the optocoupler is used to connect to the main control chip of the clothes dryer;

[0012] The preferred technical solution adopted by the present utility model to solve the above technical problems is as follows: It further includes a protection module, which is used to connect to an AC power supply, and the input end of the rectification module is connected to the protection module;

[0013] The protection module includes a thermistor, a varistor, and a fuse; the thermistor, the varistor, and the fuse are connected in series in sequence. The other end of the thermistor is used to connect to the live wire of the AC power supply, and the other end of the fuse is used to connect to the neutral wire of the AC power supply;

[0014] The positive pole of the input end of the rectification module is connected to the end of the thermistor that is used to connect to the live wire of the AC power supply, and the negative pole of the input end of the rectification module is connected to the end of the fuse that is used to connect to the neutral wire of the AC power supply.

[0015] The preferred technical solution adopted by the present utility model to solve the above technical problems is as follows: The rectification module includes a rectifier bridge; the positive pole of the input end of the rectifier bridge is the positive pole of the input end of the rectification module, and the negative pole of the input end of the rectifier bridge is the negative pole of the input end of the rectification module; the positive pole of the output end of the rectifier bridge is the positive pole of the output end of the rectification module, and the negative pole of the output end of the rectifier bridge is the negative pole of the output end of the rectification module.

[0016] The preferred technical solution adopted by the present utility model to solve the above technical problems is as follows: The optocoupler module further includes a fifth resistor, a sixth resistor, and a capacitor; one end of the fifth resistor is connected to the C pole of the receiving end of the optocoupler, and the other end of the fifth resistor is used to connect to the main control chip of the clothes dryer;

[0017] One end of the sixth resistor is connected to the node between the C pole of the receiving end of the optocoupler and the fifth resistor, and the other end of the sixth resistor is used to connect to the positive pole of the DC power supply;

[0018] One end of the capacitor is connected to the end of the fifth resistor that is used to connect to the main control chip of the clothes dryer, and the other end of the capacitor is connected to the E pole of the receiving end of the optocoupler.

[0019] Another technical solution adopted by the present utility model to solve the above technical problems is as follows: A zero-crossing signal protection circuit for a clothes dryer relay, which includes a rectification module, a voltage stabilization module, a charge and discharge module, and an optocoupler module;

[0020] The rectification module is used to connect to an AC power supply, rectify and output direct current. The voltage stabilization module is connected to the output end of the rectification module. The optocoupler module is used to connect to the main control chip of the clothes dryer, and the charge and discharge module is connected in parallel between the voltage stabilization module and the optocoupler module;

[0021] The voltage stabilizing module includes a first resistor and a voltage stabilizing diode; one end of the first resistor is connected to the positive electrode of the output end of the rectifying module, and the other end of the first resistor is connected to the negative electrode of the voltage stabilizing diode; the positive electrode of the voltage stabilizing diode is connected to the negative electrode of the output end of the rectifying module;

[0022] The charge and discharge module includes a diode, an electrolytic capacitor and a P-MOS transistor; the positive electrode of the diode is connected to the negative electrode of the voltage stabilizing diode, and the negative electrode of the diode is connected to the source electrode of the P-MOS transistor; the positive electrode of the electrolytic capacitor is connected to the node between the negative electrode of the diode and the source electrode of the P-MOS transistor, and the negative electrode of the electrolytic capacitor is connected to the positive electrode of the voltage stabilizing diode; the gate electrode of the P-MOS transistor is connected to the node between the negative electrode of the voltage stabilizing diode and the positive electrode of the diode;

[0023] The optocoupler module includes an optocoupler. The positive electrode of the emitter of the optocoupler is connected to the drain electrode of the P-MOS transistor. The negative electrode of the emitter of the optocoupler is connected to the node between the positive electrode of the voltage stabilizing diode and the negative electrode of the electrolytic capacitor. The E electrode of the receiving end of the optocoupler is grounded, and the C electrode of the receiving end of the optocoupler is used to access the main control chip of the clothes dryer.

[0024] A preferred embodiment of another technical solution adopted by the present invention to solve the above technical problems is that: the voltage stabilizing module further includes a second resistor and a third resistor; the second resistor and the third resistor are connected in series. The other end of the second resistor is connected to the node between the first resistor and the negative electrode of the voltage stabilizing diode. The other end of the third resistor is connected to the negative electrode of the output end of the rectifying module; the resistance value of the first resistor is greater than the sum of the resistance values of the second resistor and the third resistor.

[0025] A preferred embodiment of another technical solution adopted by the present invention to solve the above technical problems is that: a protection module is further included. The protection module is used to access the AC power supply, and the input end of the rectifying module is connected to the protection module;

[0026] The protection module includes a thermistor, a varistor and a fuse; the thermistor, the varistor and the fuse are connected in series in sequence. The other end of the thermistor is used to access the live wire of the AC power supply, and the other end of the fuse is used to access the neutral wire of the AC power supply;

[0027] The positive electrode of the input end of the rectifying module is connected to the end of the thermistor for accessing the live wire of the AC power supply, and the negative electrode of the input end of the rectifying module is connected to the end of the fuse for accessing the neutral wire of the AC power supply.

[0028] Another preferred technical solution adopted by the present utility model to solve the above technical problems is as follows: The rectification module includes a rectifier bridge; the positive electrode of the input end of the rectifier bridge is the positive electrode of the input end of the rectification module, and the negative electrode of the input end of the rectifier bridge is the negative electrode of the input end of the rectification module; the positive electrode of the output end of the rectifier bridge is the positive electrode of the output end of the rectification module, and the negative electrode of the output end of the rectifier bridge is the negative electrode of the output end of the rectification module.

[0029] Another preferred technical solution adopted by the present utility model to solve the above technical problems is as follows: The optocoupler module further includes a fifth resistor, a sixth resistor and a capacitor; one end of the fifth resistor is connected to the C pole of the receiving end of the optocoupler, and the other end of the fifth resistor is used for accessing the main control chip of the clothes dryer.

[0030] One end of the sixth resistor is connected to the node between the C pole of the receiving end of the optocoupler and the fifth resistor, and the other end of the sixth resistor is used for accessing the positive pole of the DC power supply.

[0031] One end of the capacitor is connected to the end of the fifth resistor for accessing the main control chip of the clothes dryer, and the other end of the capacitor is connected to the E pole of the receiving end of the optocoupler.

[0032] Another technical solution adopted by the present utility model to solve the above technical problems is: a zero-crossing signal protection system for a clothes dryer relay, including a main chip of the clothes dryer, a relay module and a zero-crossing signal protection circuit for the clothes dryer relay.

[0033] The C pole of the receiving end of the optocoupler is connected to the zero-crossing signal protection port of the main chip of the clothes dryer, and the relay control port of the main chip of the clothes dryer is connected to the corresponding relay of the relay module.

[0034] When a zero-crossing signal appears in the AC power supply, the zero-crossing signal protection circuit of the clothes dryer relay inputs a low-level signal to the zero-crossing signal protection port of the main chip of the clothes dryer, and the relay control port of the main chip of the clothes dryer inputs a high-level signal to the relay module to maintain the contact switch of the corresponding relay in a closed state.

[0035] Compared with the prior art, the advantages of the present utility model are as follows: The DC current output by the rectification module is converted into a small current through the first resistor of the voltage stabilization module, which can not only effectively prevent other components in the circuit from being damaged due to overload and overheating, but also reduce the power consumption of the entire zero-crossing signal protection circuit of the drying machine relay and improve the protection response speed. The on-off of the optocoupler is controlled by the charging and discharging mechanism of the P-MOS transistor and the electrolytic capacitor of the charging and discharging module, and then the high and low level signals of the input zero-crossing signal protection port are controlled. Compared with the prior art, it not only greatly reduces the power consumption and improves the protection response speed, but also effectively shortens the delay between the protection response and the occurrence of the zero-crossing signal, reducing the occurrence of false triggering. Description of the Drawings

[0036] The present utility model will be further described in detail below in conjunction with the drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are only drawn for the purpose of explaining the preferred embodiments and should not be construed as limiting the scope of the present utility model. In addition, unless otherwise specified, the drawings only schematically show the composition or structure of the described object and may include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0037] Figure 1 is the circuit system block diagram of the main machine of the electric drying machine in the prior art;

[0038] Figure 2 is the circuit system block diagram of the zero-crossing signal protection circuit of the drying machine relay;

[0039] Figure 3 is the circuit diagram of the zero-crossing signal protection system of the drying machine relay;

[0040] Figure 4 is the circuit system block diagram of the main machine of the electric drying machine with the zero-crossing signal protection circuit of the drying machine relay embedded;

[0041] Description of the Reference Numerals in the Drawings:

[0042] Zero-crossing signal protection system 200 of the drying machine relay, main chip 210 of the drying machine, relay module 220, fan relay module 221, heating relay module 222, zero-crossing signal protection circuit 100 of the drying machine relay, rectification module 101, voltage stabilization module 102, charging and discharging module 103, optocoupler module 104, protection module 105. Detailed Embodiments

[0043] The preferred embodiments of the present utility model will be described in detail below with reference to the drawings. Those skilled in the art will understand that these descriptions are only descriptive and exemplary and should not be construed as limiting the protection scope of the present utility model.

[0044] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present utility model is usually placed during use. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. The terms "first" and "second" are only for descriptive convenience and have no other directional meaning, and should not be construed as a limitation to the present utility model.

[0045] As Figure 3 shown is the circuit diagram of the zero-crossing signal protection system 200 for the clothes dryer relay provided in this embodiment, which includes a clothes dryer main chip 210, a relay module 220, and a zero-crossing signal protection circuit 100 for the clothes dryer relay. Three ports of the clothes dryer main chip 210 are shown in the figure, including a fan start port FAN_ON, a heating start port PTC_ON, and a zero-crossing signal protection port ZERO. Among them, the fan start port FAN_ON and the heating start port PTC_ON belong to relay control ports and are connected to the relays corresponding to the relay module 220.

[0046] The relay module 220 includes a fan relay module 221 and a heating relay module 222. Among them, the fan relay module 221 includes a fan relay and its corresponding contact switch K1, and the heating relay module 222 includes a heating relay and its corresponding contact switch K2. One end of the fan relay and the heating relay is connected to a 12V DC power supply, and the other ends are respectively connected to the fan start port FAN_ON and the heating start port PTC_ON of the clothes dryer main chip 210. The contact switches K1 and K2 are normally open contact switches, and one end of each is connected to the power supply of the clothes dryer.

[0047] When the fan start port FAN_ON of the clothes dryer main chip 210 sends a high-level signal to the fan relay, its corresponding contact switch K1 closes to start the fan of the clothes dryer; conversely, when the fan start port FAN_ON of the clothes dryer main chip 210 sends a low-level signal to the fan relay, its corresponding contact switch K1 opens to turn off the fan of the clothes dryer.

[0048] Similarly, when the heating start port PTC_ON of the clothes dryer main chip 210 sends a high-level signal to the heating relay, its corresponding contact switch K2 closes, thereby starting the heater of the clothes dryer; conversely, when the heating start port PTC_ON of the clothes dryer main chip 210 sends a low-level signal to the heating relay, its corresponding contact switch K2 opens to turn off the heater of the clothes dryer.

[0049] It should be noted that due to the limited content space in this embodiment, only the fan relay module 221 and the heating relay module 222 are used as examples. In fact, the relay module 220 of the clothes dryer also includes multiple relay control modules such as a lifting motor relay module and a disinfection relay module, and corresponding control ports are provided on the main chip 210 of the clothes dryer. The zero-crossing signal generated by the AC power supply will also have a negative impact on these relay modules and the corresponding hardware mechanisms.

[0050] The zero-crossing signal protection circuit 100 of the clothes dryer relay is connected to the zero-crossing signal protection port ZERO of the main chip 210 of the clothes dryer. When a zero-crossing signal appears in the AC power supply CN1, the zero-crossing signal protection circuit 100 of the clothes dryer relay inputs a low-level signal to the zero-crossing signal protection port ZERO of the main chip 210 of the clothes dryer, and the relay control port ZERO of the main chip 210 of the clothes dryer inputs a high-level signal to the relay module 220 to maintain the contact switches K1 and K2 of the corresponding relay in a closed state, thereby preventing the contact switches K1 and K2 of the relay from accidentally opening due to the zero-crossing voltage of the AC power supply.

[0051] Specifically, looking at the zero-crossing signal protection circuit 100 of the clothes dryer relay, as Figure 2 and Figure 3 shown, it includes a rectification module 101, a voltage stabilization module 102, a charge and discharge module 103, and an optocoupler module 104. Among them, the rectification module 101 is used to connect to the AC power supply CN1, rectify and output direct current. The AC power supply CN1 in this embodiment is the 220V AC mains power in our country. The voltage stabilization module 102 is connected to the output end of the rectification module 101, the optocoupler module 104 is used to connect to the main control chip 210 of the clothes dryer, and the charge and discharge module 103 is connected in parallel between the voltage stabilization module 102 and the optocoupler module 104.

[0052] The voltage stabilization module 102 includes a first resistor R1 and a voltage stabilizing diode D1. One end of the first resistor R1 is connected to the positive pole (pin 3) of the output end of the rectification module 101, and the other end of the first resistor R1 is connected to the negative pole of the voltage stabilizing diode D1. The positive pole of the voltage stabilizing diode D1 is connected to the negative pole (pin 4) of the output end of the rectification module 101.

[0053] Furthermore, in this embodiment, the voltage stabilization module 102 also includes a second resistor R2 and a third resistor R3. The second resistor R2 and the third resistor R3 are connected in series. The other end of the second resistor R2 is connected to the node between the first resistor R1 and the negative pole of the voltage stabilizing diode D1, and the other end of the third resistor R3 is connected to the negative pole (pin 4) of the output end of the rectification module 101. Thus, after the second resistor R2 and the third resistor R3 are connected in series, they are used as voltage dividing resistors and connected in parallel across the voltage stabilizing diode D1.

[0054] In the voltage stabilization module 102, the function of the first resistor R1 is to convert the DC current output by the rectification module 101 into a small current, which can not only effectively prevent other components in the circuit from being damaged due to overload and overheating, but also reduce the power consumption of the entire zero-crossing signal protection circuit 100 of the clothes dryer relay and improve the protection response speed. When cooperating with the voltage dividing resistors formed by the series connection of the second resistor R2 and the third resistor R3, the resistance value of the first resistor R1 should be set to be greater than the sum of the resistance values of the second resistor R2 and the third resistor R3. For example, in this embodiment, the first resistor R1 uses a resistor with a resistance value of 1 MΩ, and the second resistor R2 and the third resistor R3 respectively use resistors with a resistance value of 25 kΩ.

[0055] The charge and discharge module 103 includes a diode D2, an electrolytic capacitor C1, and a P-MOS transistor Q1. The positive electrode of the diode D2 is connected to the negative electrode of the zener diode D1, and the negative electrode of the diode D2 is connected to the source electrode of the P-MOS transistor Q1. The positive electrode of the electrolytic capacitor C1 is connected to the node between the negative electrode of the diode D2 and the source electrode of the P-MOS transistor Q1, and the negative electrode of the electrolytic capacitor C1 is connected to the positive electrode of the zener diode D1. The gate electrode of the P-MOS transistor Q1 is connected to the node between the negative electrode of the zener diode D1 and the positive electrode of the diode D2.

[0056] The optocoupler module 104 includes an optocoupler U1. The positive electrode (pin 1) of the emitter of the optocoupler U1 is connected to the drain electrode of the P-MOS transistor Q1, the negative electrode (pin 2) of the emitter of the optocoupler U1 is connected to the node between the positive electrode of the zener diode D1 and the negative electrode of the electrolytic capacitor C1, the E electrode (pin 3) of the receiving end of the optocoupler U1 is grounded, and the C electrode of the receiving end of the optocoupler U1 is used to access the main control chip 210 of the clothes dryer.

[0057] Further, in this embodiment, the optocoupler module 104 further includes a fifth resistor R5, a sixth resistor R6, and a capacitor C2. One end of the fifth resistor R5 is connected to the C electrode (pin 4) of the receiving end of the optocoupler U1, and the other end of the fifth resistor R5 is used to access the main control chip 210 of the clothes dryer, that is, to access the zero-crossing signal protection port ZERO of the main control chip 210 of the clothes dryer. One end of the sixth resistor R6 is connected to the node between the C electrode (pin 4) of the receiving end of the optocoupler U1 and the fifth resistor R5, and the other end of the sixth resistor R6 is used to access the positive electrode of the DC power supply, which is connected to the 5V DC power supply in this embodiment.

[0058] Since the capacitor C2 is not specifically described, it means a common capacitor is used. One end of the capacitor C2 is connected to the end of the fifth resistor R5 for accessing the main control chip 210 of the clothes dryer, and the other end of the capacitor C2 is connected to the E electrode (pin 3) of the receiving end of the optocoupler U1. Since the E electrode (pin 3) of the receiving end of the optocoupler U1 is grounded, this end of the capacitor C2 is also grounded.

[0059] When the clothes dryer is operating normally, the gate of the P-MOS transistor Q1 is at a high level, and the P-MOS transistor Q1 is cut off. At this time, the electrolytic capacitor C1 is charged, and there is no current passing between the positive and negative electrodes (pin 1 and pin 2) of the emitter of the optocoupler U1. Therefore, the E and C electrodes (pin 3 and pin 4) of the receiving end of the optocoupler U1 are open. At this time, the zero-crossing signal protection port ZERO input to the main control chip 210 of the clothes dryer is at a high-level signal, which does not affect the main control chip 210 of the clothes dryer from sending signals to the relay module as usual.

[0060] When a zero-crossing signal appears in the AC power supply CN1, the gate of the P-MOS transistor Q1 appears at a low level, and the P-MOS transistor Q1 conducts. At this time, the electrolytic capacitor C1 starts to discharge, and there is current passing between the positive and negative electrodes (pin 1 and pin 2) of the emitter of the optocoupler U1. Therefore, the E and C electrodes (pin 3 and pin 4) of the receiving end of the optocoupler U1 are conducting. At this time, the zero-crossing signal protection port ZERO input to the main control chip 210 of the clothes dryer becomes a low-level signal. Furthermore, the fan start port FAN_ON and the heating start port PTC_ON of the main control chip 210 of the clothes dryer are maintained at a high level, and the contact switches K1 and K2 corresponding to the fan relay and the heating relay are maintained in the closed state. The fan and heater of the clothes dryer are simultaneously maintained in the normal operating state. This can reduce the damage caused by the accidental opening of the relay contact switch due to the appearance of the zero-crossing signal, and the hardware mechanisms such as the fan, heater, and lifting assembly of the clothes dryer due to frequent sudden stops, ensuring that the normal operation of the clothes dryer is not affected by the zero-crossing signal.

[0061] It can be seen that the zero-crossing signal protection circuit 100 for the clothes dryer relay provided by the present utility model changes the DC current output by the rectification module 101 into a small current through the first resistor R1 of the voltage stabilization module 102, which can not only effectively avoid the overload and overheat damage of other components in the circuit, but also reduce the power consumption of the entire zero-crossing signal protection circuit 100 for the clothes dryer relay and improve the protection response speed. By means of the charging and discharging mechanism of the mutual cooperation between the P-MOS transistor Q1 and the electrolytic capacitor C1 of the charging and discharging module 103 to control the on-off of the optocoupler U1, and then control the high and low level signals of the zero-crossing signal protection port ZERO input. Compared with the prior art, it not only greatly reduces the power consumption and improves the protection response speed, but also effectively shortens the delay between the protection response and the occurrence of the zero-crossing signal, reducing the occurrence of false triggering.

[0062] Further, the zero-crossing signal protection circuit 100 of the clothes dryer relay further includes a protection module 105. The protection module 105 is used to connect to the AC power supply CN1, and the input end of the rectification module 101 is connected to the protection module 105. The protection module 105 includes a thermistor RT1, a varistor RZ1, and a fuse FUSE1. The thermistor RT1, the varistor RZ1, and the fuse FUSE1 are connected in series in sequence. The other end of the thermistor RT1 is used to connect to the live wire (pin 1) of the AC power supply CN1, and the other end of the fuse FUSE1 is used to connect to the neutral wire (pin 2) of the AC power supply CN1.

[0063] The positive pole (pin 1) of the input end of the rectification module 101 is connected to one end of the thermistor RT1 that is used to connect to the live wire (pin 1) of the AC power supply CN1, and the negative pole (pin 2) of the input end of the rectification module 101 is connected to one end of the fuse FUSE1 that is used to connect to the neutral wire (pin 2) of the AC power supply CN1.

[0064] In addition, a transformer L1 is also connected in parallel with the varistor RZ1 of the protection module 105 to supply power to other modules of the clothes dryer main unit. For the circuit system block diagram of the overall power supply system and control system of the clothes dryer main unit, reference can be made to Figure 4 . It can be seen that the protection module 105 plays the roles of overheat protection, overpressure protection, and overcurrent protection for both the zero-crossing signal protection circuit 100 of the clothes dryer relay and other modules of the clothes dryer main unit.

[0065] In this embodiment, the rectification module 101 includes a rectifier bridge DB1. The positive pole (pin 1) of the input end of the rectifier bridge DB1 is the positive pole of the input end of the rectification module 101, and the negative pole (pin 2) of the input end of the rectifier bridge DB1 is the negative pole of the input end of the rectification module 101. The positive pole (pin 3) of the output end of the rectifier bridge DB1 is the positive pole of the output end of the rectification module 101, and the negative pole (pin 4) of the output end of the rectifier bridge DB1 is the negative pole of the output end of the rectification module 101.

[0066] Using the rectifier bridge DB1 for AC-DC conversion can overcome the problem of low voltage utilization rate caused by half-wave rectification in the prior art. Of course, in other embodiments, other rectification methods can also be used, such as using a dedicated ADC chip, etc. However, the overall production cost of the clothes dryer and the weight of the zero-crossing signal protection circuit in the overall cost-benefit of the clothes dryer need to be considered.

[0067] It should be noted that similar reference numerals represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it may not be further defined and explained in subsequent drawings.

[0068] The above has introduced the zero-crossing signal protection circuit and protection system of the clothes dryer relay provided by the present utility model. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the present utility model and its core idea. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present utility model, several improvements and modifications can be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. The zero-crossing signal protection circuit of the clothes drying machine relay is characterized by: Including rectification module, voltage stabilization module, charging and discharging module and optocoupler module; The rectifier module is used to connect to the AC power supply, rectify and output DC power, the voltage stabilizing module is connected to the output end of the rectifier module, the optical coupling module is used to connect to the main control chip of the clothes drying machine, and the charging and discharging module is connected in parallel between the voltage stabilizing module and the optical coupling module; The voltage stabilizing module includes a first resistor, a second resistor, a third resistor and a voltage stabilizing diode; one end of the first resistor is connected to the positive electrode of the output end of the rectifier module, and the other end of the first resistor is connected to the negative electrode of the voltage stabilizing diode; the positive electrode of the voltage stabilizing diode is connected to the negative electrode of the output end of the rectifier module; the second resistor is connected in series with the third resistor, the other end of the second resistor is connected to the node between the first resistor and the negative electrode of the voltage stabilizing diode, and the other end of the third resistor is connected to the negative electrode of the output end of the rectifier module; the resistance value of the first resistor is greater than the sum of the resistance values ​​of the second resistor and the third resistor; The charging and discharging module includes a diode, an electrolytic capacitor and a P-MOS tube; the positive electrode of the diode is connected to the negative electrode of the voltage stabilizing diode, and the negative electrode of the diode is connected to the source electrode of the P-MOS tube; the positive electrode of the electrolytic capacitor is connected to the node between the negative electrode of the diode and the source electrode of the P-MOS tube, and the negative electrode of the electrolytic capacitor is connected to the positive electrode of the voltage stabilizing diode; the gate electrode of the P-MOS tube is connected to the node between the negative electrode of the voltage stabilizing diode and the positive electrode of the diode; The optocoupler module includes a photocoupler, the positive electrode of the emitter of the photocoupler is connected to the drain of the P-MOS tube, the negative electrode of the emitter of the photocoupler is connected to the node between the positive electrode of the voltage regulator diode and the negative electrode of the electrolytic capacitor, the E electrode of the receiving end of the photocoupler is grounded, and the C electrode of the receiving end of the photocoupler is used to connect to the main control chip of the clothes drying machine.

2. The clothes drying machine relay zero-crossing signal protection circuit according to claim 1, characterized in that: It also includes a protection module, which is used to connect to an AC power supply, and the input end of the rectifier module is connected to the protection module; The protection module includes a thermistor, a varistor and a fuse; the thermistor, the varistor and the fuse are connected in series in sequence, the other end of the thermistor is used to connect to the live wire of the AC power supply, and the other end of the fuse is used to connect to the neutral wire of the AC power supply; The positive pole of the input end of the rectifier module is connected to one end of the live wire of the thermistor for connecting to the AC power supply, and the negative pole of the input end of the rectifier module is connected to one end of the neutral wire of the fuse for connecting to the AC power supply.

3. The clothes drying machine relay zero-crossing signal protection circuit according to claim 1, characterized in that: The rectifier module includes a rectifier bridge; the positive pole of the input end of the rectifier bridge is the positive pole of the input end of the rectifier module, and the negative pole of the input end of the rectifier bridge is the negative pole of the input end of the rectifier module; the positive pole of the output end of the rectifier bridge is the positive pole of the output end of the rectifier module, and the negative pole of the output end of the rectifier bridge is the negative pole of the output end of the rectifier module.

4. The clothes drying machine relay zero-crossing signal protection circuit according to claim 1, characterized in that: The optical coupling module also includes a fifth resistor, a sixth resistor and a capacitor; one end of the fifth resistor is connected to the C pole of the receiving end of the photoelectric coupler, and the other end of the fifth resistor is used to connect to the main control chip of the clothes drying machine; One end of the sixth resistor is connected to the node between the C pole of the receiving end of the photoelectric coupler and the fifth resistor, and the other end of the sixth resistor is used to connect to the positive pole of the DC power supply; One end of the capacitor is connected to the fifth resistor for accessing one end of the main control chip of the clothes drying machine, and the other end of the capacitor is connected to the E pole of the receiving end of the photoelectric coupler.

5. The zero-crossing signal protection circuit of the clothes drying machine relay is characterized by: Including rectification module, voltage stabilization module, charging and discharging module and optocoupler module; The rectifier module is used to connect to the AC power supply, rectify and output DC power, the voltage stabilizing module is connected to the output end of the rectifier module, the optical coupling module is used to connect to the main control chip of the clothes drying machine, and the charging and discharging module is connected in parallel between the voltage stabilizing module and the optical coupling module; The voltage stabilizing module includes a first resistor and a voltage stabilizing diode; one end of the first resistor is connected to the positive electrode of the output end of the rectifier module, and the other end of the first resistor is connected to the negative electrode of the voltage stabilizing diode; the positive electrode of the voltage stabilizing diode is connected to the negative electrode of the output end of the rectifier module; The charging and discharging module includes a diode, an electrolytic capacitor and a P-MOS tube; the positive electrode of the diode is connected to the negative electrode of the voltage stabilizing diode, and the negative electrode of the diode is connected to the source electrode of the P-MOS tube; the positive electrode of the electrolytic capacitor is connected to the node between the negative electrode of the diode and the source electrode of the P-MOS tube, and the negative electrode of the electrolytic capacitor is connected to the positive electrode of the voltage stabilizing diode; the gate electrode of the P-MOS tube is connected to the node between the negative electrode of the voltage stabilizing diode and the positive electrode of the diode; The optocoupler module includes a photocoupler, the positive electrode of the emitter of the photocoupler is connected to the drain of the P-MOS tube, the negative electrode of the emitter of the photocoupler is connected to the node between the positive electrode of the voltage regulator diode and the negative electrode of the electrolytic capacitor, the E electrode of the receiving end of the photocoupler is grounded, and the C electrode of the receiving end of the photocoupler is used to connect to the main control chip of the clothes drying machine.

6. The clothes drying machine relay zero-crossing signal protection circuit according to claim 5, characterized in that: The voltage stabilizing module also includes a second resistor and a third resistor; the second resistor is connected in series with the third resistor, the other end of the second resistor is connected to the node between the first resistor and the negative electrode of the voltage stabilizing diode, and the other end of the third resistor is connected to the negative electrode of the output end of the rectifier module; the resistance of the first resistor is greater than the sum of the resistances of the second resistor and the third resistor.

7. The clothes drying machine relay zero-crossing signal protection circuit according to claim 5, characterized in that: It also includes a protection module, which is used to connect to an AC power supply, and the input end of the rectifier module is connected to the protection module; The protection module includes a thermistor, a varistor and a fuse; the thermistor, the varistor and the fuse are connected in series in sequence, the other end of the thermistor is used to connect to the live wire of the AC power supply, and the other end of the fuse is used to connect to the neutral wire of the AC power supply; The positive pole of the input end of the rectifier module is connected to one end of the live wire of the thermistor for connecting to the AC power supply, and the negative pole of the input end of the rectifier module is connected to one end of the neutral wire of the fuse for connecting to the AC power supply.

8. The clothes drying machine relay zero-crossing signal protection circuit according to claim 5, characterized in that: The rectifier module includes a rectifier bridge; the positive pole of the input end of the rectifier bridge is the positive pole of the input end of the rectifier module, and the negative pole of the input end of the rectifier bridge is the negative pole of the input end of the rectifier module; the positive pole of the output end of the rectifier bridge is the positive pole of the output end of the rectifier module, and the negative pole of the output end of the rectifier bridge is the negative pole of the output end of the rectifier module.

9. The clothes drying machine relay zero-crossing signal protection circuit according to claim 5, characterized in that: The optical coupling module also includes a fifth resistor, a sixth resistor and a capacitor; one end of the fifth resistor is connected to the C pole of the receiving end of the photoelectric coupler, and the other end of the fifth resistor is used to connect to the main control chip of the clothes drying machine; One end of the sixth resistor is connected to the node between the C pole of the receiving end of the photoelectric coupler and the fifth resistor, and the other end of the sixth resistor is used to connect to the positive pole of the DC power supply; One end of the capacitor is connected to the fifth resistor for accessing one end of the main control chip of the clothes drying machine, and the other end of the capacitor is connected to the E pole of the receiving end of the photoelectric coupler.

10. The clothes drying machine relay zero-crossing signal protection system is characterized by: It comprises a clothes drying machine main chip, a relay module and a clothes drying machine relay zero-crossing signal protection circuit as claimed in any one of claims 1 to 9; The C pole of the receiving end of the photoelectric coupler is connected to the zero-crossing signal protection port of the clothes drying machine main chip, and the relay control port of the clothes drying machine main chip is connected to the relay corresponding to the relay module; When a zero-crossing signal appears in the AC power supply, the clothes drying machine relay zero-crossing signal protection circuit inputs a low-level signal to the zero-crossing signal protection port of the clothes drying machine main chip, and the relay control port of the clothes drying machine main chip inputs a high-level signal to the relay module to maintain the corresponding contact switch of the relay closed.

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