Control method for keeping original working state after power-off and power-on

Abstract

The invention relates to the field of power-off control, in particular to a control method for keeping an original working state after power-on after power-off, which comprises a zero-crossing detection module, an MCU module, a step-down control module, an output driving module and a low-speed clock, and is characterized in that the zero-crossing detection module is used for detecting a mains supply zero-crossing point signal, and when the zero-crossing point signal does not appear for a long time, power-off is judged to appear; the MCU module closes an electric device, enters a low-power-consumption module, performs timed wakeup on the MCU module by using a low-speed clock, performs delayed power-on if a zero crossing point signal appears within the timed wakeup time, and starts the step-down control module in the delayed power-on process, so that the situation that a high-power-consumption load works when the step-down control module is not started is avoided, and the service life of the step-down control module is prolonged. And the electric quantity stored in the power supply capacitor is quickly consumed, so that the MCU is reset and cannot keep the original working state.

Description

Technical Field

[0001] This invention relates to the field of power failure control, and more specifically to a control method for maintaining the original working state after a power failure and subsequent power restoration. Background Technology

[0002] Electrical equipment is ubiquitous in industrial production and daily life. However, various situations can lead to power outages during actual use, affecting equipment operation. For example, overvoltage or short-circuit protection triggers, or voltage fluctuations cause temporary power outages. When power is restored, the equipment is often in a paused or restarted state, causing programs to repeat and impacting equipment use. Therefore, some electrical equipment manufacturers require the ability to maintain or quickly restore their original operating state after a power outage to ensure operational continuity, safety, and data integrity.

[0003] Taking industrial production as an example, PLC equipment controls the logic of the entire production line. After a power outage, it needs to restore the program execution points, register values, and I / O states, possibly requiring continuation from the breakpoint. Similarly, some process control instruments need to maintain set values ​​(such as PID parameters and cumulative flow) when power is restored after a power outage. In everyday electrical appliances, such as rice cookers, which are common kitchen appliances, use a heating plate to convert electrical energy into heat to cook rice and water in the inner pot. When power is restored after a power outage, the rice cooker needs to resume its original operating state to ensure the quality and taste of the rice.

[0004] Therefore, this invention proposes a control method for maintaining the original working state after power failure and power restoration. Summary of the Invention

[0005] The purpose of this invention is to provide a control method for maintaining the original working state after power failure and power restoration, aiming to improve the problem that most existing electrical equipment is in a paused or restarted state after power failure and power restoration, resulting in repeated program execution and affecting the use of the equipment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A control method for maintaining the original working state after power failure and power restoration includes a zero-crossing detection module, an MCU module, a buck control module, an output drive module, and a low-speed clock;

[0008] The zero-crossing detection module and the step-down control module are electrically connected to the mains power. The output terminal of the zero-crossing detection module is electrically connected to the MCU module. The step-down control module supplies power to the MCU module and the output drive module. The control terminal of the MCU module is electrically connected to the step-down control module and the output drive module.

[0009] Specifically, it includes the following steps:

[0010] The zero-crossing detection module detects the zero-crossing signal of the mains power. When the zero-crossing signal occurs, it outputs a low level to the MCU module. The internal timer of the MCU module counts the high level time. When a low level signal occurs, the timer is reset to zero. When the timer counts for a set value A, it is determined that the power is off.

[0011] The MCU module shuts down the output drive module through the buck control module, entering a low-power mode; a low-speed clock starts up the MCU module at regular intervals, and the zero-crossing detection module detects the zero-crossing signal in real time.

[0012] When the zero-crossing detection module outputs a low level within the timed wake-up time B, the low-speed clock is cleared and switched to the delay time C. When the delay time C is reached, the MCU module exits the low-power module and the output drive module is turned on through the buck control module, and the electrical appliance continues to work.

[0013] When the low-speed clock timing exceeds the timer wake-up time B, the low-power module exits, and the MCU module switches its working state to the initial power-on state to wait for power-on; if it continues not to power on, the capacitor stored in the buck control module is consumed, and the MCU module is reset.

[0014] Furthermore, the set value A is greater than 1 / 2 of the power grid cycle.

[0015] Furthermore, the delay time C is greater than the startup time of the buck control module.

[0016] Furthermore, the step-down control module includes a switching power supply circuit and a step-down power supply control circuit;

[0017] The power input terminal of the switching power supply circuit is connected to the mains power, and the output terminal of the switching power supply circuit outputs a +12V voltage to the step-down power supply control circuit and the output drive module.

[0018] The step-down power supply control circuit includes a voltage regulator chip U2, a MOSFET Q3, polarized capacitors EC6 and EC7, capacitor C7, and resistors R23, R24, R25, and R26.

[0019] One end of resistor R23 and one end of resistor R24 ​​are electrically connected to the output terminal of the switching power supply circuit. The other end of resistor R23 is electrically connected to the other end of resistor R24, the positive terminal of polarized capacitor EC6, one end of capacitor C7, and the input terminal of voltage regulator chip U2. The output terminal of voltage regulator chip U2 is electrically connected to the positive terminal of polarized capacitor EC7, one end of resistor R25, and the source of MOSFET Q3, and outputs a +5V voltage to the MCU module and the zero-crossing detection module.

[0020] The first control terminal of the MCU module is electrically connected to one end of resistor R26, the other end of resistor R26 is electrically connected to the gate of MOSFET Q3 and the other end of resistor R25, and the drain of MOSFET Q3 outputs a 5V voltage to the external power circuit.

[0021] The ground terminal of the voltage regulator chip U2, the negative terminal of the polarized capacitor EC6, the negative terminal of the polarized capacitor EC7, and the other end of the capacitor C7 are all grounded.

[0022] Furthermore, the zero-crossing detection module includes an optocoupler U4, a diode D7, capacitors C13 and C14, and resistors R37, R38, and R39.

[0023] The resistors R37 and R38 are connected in series between the live wire and pin 1 of the optocoupler U4. The negative terminal of the diode D7 is electrically connected to pin 1 of the optocoupler U4, and pin 2 of the optocoupler U4 is electrically connected to the positive terminal of the diode D7 and the neutral wire.

[0024] Pin 4 of the optocoupler U4 is electrically connected to one end of resistor R39, one end of capacitor C13 and one end of capacitor C14, and is electrically connected to the MCU module as an output terminal. The buck control module outputs a +5V voltage to the other end of MOSFET R39.

[0025] Pin 3 of the optocoupler U4, the other end of capacitor C13, and the other end of capacitor C14 are all grounded.

[0026] Furthermore, the MCU module includes a control chip U3 and a capacitor C9;

[0027] The step-down control module outputs a +5V voltage to one end of capacitor C9 and pin 1 of control chip U3, and the other end of capacitor C9 is grounded; pin 5 of control chip U3 is electrically connected to the output of the zero-crossing detection module; pins 8, 9, 10 and 12 of control chip U3 are electrically connected to the output drive module; pin 15 of control chip U3 is electrically connected to one end of resistor R26.

[0028] Furthermore, the model number of the control chip U3 is TM56E0C6422S.

[0029] Furthermore, the output drive module includes a MOSFET Q1, an interface CN5, a diode D1, a capacitor C3, and resistors R8, R13, R17, R18, and R19.

[0030] The second control terminal of the MCU module is electrically connected to one end of resistor R8, and the third control terminal of the MCU module is electrically connected to one end of resistor R17 and one end of capacitor C3.

[0031] The other end of resistor R17 is electrically connected to one end of resistor R18, one end of resistor R19, one end of resistor R13, and the source of MOSFET Q1; the other end of resistor R8 is electrically connected to the other end of resistor R13 and the gate of MOSFET Q1; the drain of MOSFET Q1 is electrically connected to the anode of diode D1 and pin 2 of interface CN5; the +12V output of the buck control module is supplied to pin 1 of interface CN5 and the cathode of diode D1; interface CN5 is connected to the power supply device.

[0032] The other ends of capacitor C3, resistor R18, and resistor R19 are all grounded.

[0033] Furthermore, the output drive module also includes interface CN6, diode D2, MOSFET Q2, and resistors R9 and R14;

[0034] The fourth control terminal of the MCU module is electrically connected to one end of resistor R9, and the other end of resistor R9 is electrically connected to the gate of MOSFET Q2 and one end of resistor R14; the drain of MOSFET Q2 is electrically connected to the anode of diode D2 and pin 2 of interface CN6; the output of the buck control module is +12V to pin 1 of interface CN6 and the cathode of diode D2; interface CN6 is connected to the power-consuming device.

[0035] The other end of the resistor R14 and the source of the MOSFET Q2 are both grounded.

[0036] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0037] The zero-crossing detection module detects the zero-crossing signal of the mains power. If no zero-crossing signal is detected for an extended period, a power outage is identified. The MCU module shuts down the powered devices and enters a low-power mode. A low-speed clock is used to periodically wake up the MCU module. If a zero-crossing signal is detected within the timed wake-up period, the MCU module performs a delayed power-on. During the delayed power-on process, the buck control module is activated. This prevents high-power loads from operating before the buck control module is activated, which would rapidly deplete the power stored in the power capacitor, causing the MCU to reset and lose its original operating state. This ensures that when the MCU module controls the powered devices, the buck control module can provide the required voltage, thus allowing the powered devices to maintain their original operating state. Attached Figure Description

[0038] Figure 1This is a block diagram of the control method for maintaining the original working state after power failure and power restoration according to the present invention;

[0039] Figure 2 The circuit diagram of the switching power supply for the control method of maintaining the original working state after power failure and power restoration as described in this invention;

[0040] Figure 3 This is a circuit diagram of the step-down power supply control circuit for the control method of maintaining the original working state after power failure and power restoration as described in this invention.

[0041] Figure 4 This is a circuit diagram of the MCU module for the control method of maintaining the original working state after power failure and power restoration as described in this invention.

[0042] Figure 5 This is a circuit diagram of the zero-crossing detection module of the control method for maintaining the original working state after power failure and power restoration as described in this invention.

[0043] Figure 6 This is a circuit diagram of the first part of the output drive module of the control method for maintaining the original working state after power failure and power restoration according to the present invention.

[0044] Figure 7 This is the second part of the circuit diagram of the output drive module of the control method for maintaining the original working state after power failure and power restoration according to the present invention;

[0045] Figure 8 The circuit diagram of the electric heating tube drive circuit of the control method for maintaining the original working state after power failure and power restoration according to the present invention is shown below.

[0046] Figure 9 The circuit diagram of the temperature sensor circuit is shown in the control method for maintaining the original working state after power failure and power restoration according to the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0048] Additionally, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are all based on the orientation or positional relationship shown in the accompanying drawings. They are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element of the present invention must have a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0049] When an element is referred to as being "fixed to," "set on," or "contained on" another element, it can be directly on or indirectly on that other element. When an element is referred to as being "connected to," it can be directly connected to or indirectly connected to that other element.

[0050] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Example

[0052] Please refer to Figure 1-9 As shown, this embodiment provides a control method for maintaining the original working state after power failure and power restoration, including a zero-crossing detection module, an MCU module, a buck control module, an output driver module, and a low-speed clock. The zero-crossing detection module and the buck control module are electrically connected to the mains power. The output terminal of the zero-crossing detection module is electrically connected to the MCU module. The buck control module supplies power to the MCU module and the output driver module. The control terminal of the MCU module is electrically connected to the buck control module and the output driver module.

[0053] Specifically, the following steps are included:

[0054] The zero-crossing detection module detects the zero-crossing signal of the mains power. When a zero-crossing signal is detected, it outputs a low level to the MCU module. The MCU module's internal timer counts the high-level time. When a low-level signal is detected, the timer is reset to zero. When the timer reaches the set value A, it is determined that the power is off.

[0055] The MCU module shuts down the output drive module through the buck control module, entering a low-power mode; a low-speed clock starts up the MCU module at regular intervals, and the zero-crossing detection module detects the zero-crossing signal in real time.

[0056] When the zero-crossing detection module outputs a low level within the timed wake-up time B, the low-speed clock is cleared and switched to the delay time C. When the delay time C is reached, the MCU module exits the low-power module and the output drive module is turned on through the buck control module, and the electrical appliance continues to work.

[0057] When the low-speed clock timing exceeds the timer wake-up time B, the low-power module exits, and the MCU module switches its working state to the initial power-on state to wait for power-on; if it continues not to power on, the capacitor stored in the buck control module is consumed, and the MCU module is reset.

[0058] The zero-crossing detection module detects the zero-crossing signal of the mains power. If no zero-crossing signal is detected for an extended period, a power outage is identified. The MCU module shuts down the powered devices and enters a low-power mode. A low-speed clock is used to periodically wake up the MCU module. If a zero-crossing signal is detected within the timed wake-up period, the MCU module performs a delayed power-on. During the delayed power-on process, the buck control module is activated. This prevents high-power loads from operating before the buck control module is activated, which would rapidly deplete the power stored in the power capacitor, causing the MCU to reset and lose its original operating state. This ensures that when the MCU module controls the powered devices, the buck control module can provide the required voltage, thus allowing the powered devices to maintain their original operating state.

[0059] The setpoint A is greater than half the power grid cycle, ensuring that the timer cannot reach the setpoint A and be reset to zero during normal power supply, thereby improving the accuracy of power outage detection. Furthermore, the delay time C is greater than the startup time of the buck control module, ensuring that the buck control module can fully start and provide operating voltage to the electrical components before the MCU module controls the components to operate. This prevents the capacitor voltage of the buck control module from being rapidly consumed, causing the MCU module to reset and the components to lose their original operating state.

[0060] Please refer to Figure 2 and Figure 3 As shown, specifically, the buck control module includes a switching power supply circuit and a buck power supply control circuit; among which... Figure 2 This is a switching power supply circuit. Please refer to [the documentation]. Figure 3 As shown, the power input terminal of the switching power supply circuit is connected to the mains power, and the output terminal of the switching power supply circuit outputs a +12V voltage to the buck power supply control circuit and the output driver module. The buck power supply control circuit includes a voltage regulator chip U2, a MOSFET Q3, polarized capacitors EC6 and EC7, capacitor C7, and resistors R23, R24, R25, and R26. In this embodiment, the voltage regulator chip U2 is an HT7550.

[0061] One end of resistor R23 and one end of resistor R24 ​​are electrically connected to the output terminal of the switching power supply circuit. The other end of resistor R23 is electrically connected to the other end of resistor R24, the positive terminal of polarized capacitor EC6, one end of capacitor C7, and the input terminal of voltage regulator chip U2. The output terminal of voltage regulator chip U2 is electrically connected to the positive terminal of polarized capacitor EC7, one end of resistor R25, and the source of MOSFET Q3, and outputs a +5V voltage to the MCU module and the zero-crossing detection module.

[0062] The first control terminal of the MCU module is electrically connected to one end of resistor R26. The other end of resistor R26 is electrically connected to the gate of MOSFET Q3 and the other end of resistor R25. The drain of MOSFET Q3 outputs a 5V voltage to the external power circuit.

[0063] The ground terminal of the voltage regulator chip U2, the negative terminal of the polarized capacitor EC6, the negative terminal of the polarized capacitor EC7, and the other end of capacitor C7 are all grounded.

[0064] The switching power supply circuit connects to the mains power, converting it to 12V DC to power subsequent circuits. The step-down power supply control circuit steps down the 12V voltage to 5V to supply the MCU module, and simultaneously supplies the 5V voltage to the electrical appliances through MOSFET Q3. The operating status of the electrical appliances is controlled by controlling the on / off state of MOSFET Q3.

[0065] Please refer to Figure 5 As shown, the zero-crossing detection module includes an optocoupler U4, a diode D7, capacitors C13 and C14, and resistors R37, R38, and R39. Resistors R37 and R38 are connected in series between the live wire and pin 1 of the optocoupler U4. The cathode of diode D7 is electrically connected to pin 1 of the optocoupler U4, and pin 2 of the optocoupler U4 is electrically connected to the anode of diode D7 and the neutral wire. Pin 4 of the optocoupler U4 is electrically connected to one end of resistor R39, one end of capacitor C13, and one end of capacitor C14, and serves as the output terminal, electrically connected to the MCU module. The buck control module outputs a +5V voltage to the other end of MOSFET R39. Pin 3 of the optocoupler U4, the other end of capacitor C13, and the other end of capacitor C14 are all grounded. The zero-crossing detection module acquires the zero-crossing point of the mains power through the optocoupler U4 and transmits it to the MCU module.

[0066] Please refer to Figure 4 As shown, the MCU module includes a control chip U3 and a capacitor C9.

[0067] The step-down control module outputs +5V to one end of capacitor C9 and pin 1 of control chip U3, while the other end of capacitor C9 is grounded. Pin 5 of control chip U3 is electrically connected to the output of the zero-crossing detection module; that is, pin 4 of optocoupler U4 is electrically connected to pin 5 of control chip U3. Pins 8, 9, 10, and 12 of control chip U3 are electrically connected to the output drive module; pin 15 of control chip U3 is electrically connected to one end of resistor R26. In this embodiment, the model of control chip U3 is TM56E0C6422S.

[0068] Please refer to Figure 6As shown, the output drive module includes MOSFET Q1, interface CN5, diode D1, capacitor C3, and resistors R8, R13, R17, R18, and R19.

[0069] The second control terminal of the MCU module is electrically connected to one end of resistor R8, that is, pin 9 of control chip U3 is electrically connected to one end of resistor R8. The third control terminal of the MCU module is electrically connected to one end of resistor R17 and one end of capacitor C3, that is, pin 12 of control chip U3 is electrically connected to one end of resistor R17 and one end of capacitor C3.

[0070] The other end of resistor R17 is electrically connected to one end of resistor R18, one end of resistor R19, one end of resistor R13, and the source of MOSFET Q1; the other end of resistor R8 is electrically connected to the other end of resistor R13 and the gate of MOSFET Q1. The drain of MOSFET Q1 is electrically connected to the anode of diode D1 and pin 2 of interface CN5. The +12V output voltage of the buck control module is supplied to pin 1 of interface CN5 and the cathode of diode D1. Interface CN5 is connected to the power supply device; in this embodiment, interface CN5 is electrically connected to the water pump. The other ends of capacitor C3, resistor R18, and resistor R19 are all grounded.

[0071] Please refer to Figure 7 As shown, the output drive module also includes interface CN6, diode D2, MOSFET Q2, and resistors R9 and R14.

[0072] The fourth control terminal of the MCU module is electrically connected to one end of resistor R9, that is, pin 10 of the control chip U3 is electrically connected to one end of resistor R9. The other end of resistor R9 is electrically connected to the gate of MOSFET Q2 and one end of resistor R14. The drain of MOSFET Q2 is electrically connected to the anode of diode D2 and pin 2 of interface CN6. The +12V output voltage of the buck control module is supplied to pin 1 of interface CN6 and the cathode of diode D2. Interface CN6 is connected to the power supply device; in this embodiment, interface CN6 is electrically connected to the air pump. The other end of resistor R14 and the source of MOSFET Q2 are both grounded.

[0073] In this embodiment, the control method is applied to a coffee machine. The water pump draws water from the tank to the heating element during coffee brewing, then heats the water before it reaches the coffee capsule for brewing. The air pump blows water out of the pipes after brewing to prevent residual water from remaining in the pipes. Please refer to [reference needed]. Figure 8 As shown, attached Figure 8 This is the heating element drive circuit. Interface CN11 is electrically connected to the heating element, and one end of resistor R31 is electrically connected to pin 8 of control chip U3. Control chip U3 controls the on / off state of the heating element via a relay. Please refer to... Figure 9 As shown, attached Figure 9 The temperature sensor circuit uses an NTC converter for temperature signal detection. Two temperature sensor circuits are used, one to collect the temperature of the heating element and the other to collect the temperature of the heated water, transmitting the data to pins 6 and 7 of the control chip U3, respectively. Similarly, this control method can be applied to other electrical devices, such as rice cookers, by electrically connecting interface CN5 and / or interface CN6 to the relevant device.

[0074] During the coffee brewing process, the control chip U3 controls the air pump, water pump, and relays, and controls other electrical components via the MOSFET Q3. In this embodiment, half of the power grid cycle is approximately 10 milliseconds, and the set value A is 60 milliseconds. That is, when the zero-crossing detection module outputs a high level for 60 milliseconds, the control chip U3 controls the air pump, water pump, relays, and other electrical components to shut down, entering a low-power mode, and a low-speed clock initiates a timed wake-up.

[0075] In this embodiment, the timed wake-up time B is 1 minute. When the low-speed clock time exceeds 1 minute, the coffee machine exits the low-power mode, the MCU module switches the working state from the coffee brewing program to the initial power-on state, and consumes the stored power of the polarized capacitors EC1, EC2, EC6 and EC7, and the control chip U4 is reset.

[0076] When the zero-crossing detection module outputs a low level within 1 minute, the control chip disables the timer wake-up and controls the low-speed clock to count down for a delay time C. When the delay time C is reached, the control chip U3 enters normal operation, controls the MOSFET Q3 to turn on to provide operating voltage for other electrical components, and controls the air pump, water pump, and relay to resume their corresponding operations.

[0077] Please refer to Figure 2 As shown, the switching power supply circuit uses a switching power supply chip U1 of model S7134C. Table 1 shows the operating voltage parameters of the switching power supply chip U1.

[0078] Table 1:

[0079]

[0080] From Table 1, we can obtain V CC_ONThe voltage is 16V. When the mains power is initially connected, the polarized capacitor EC5 on the power supply pin of the switching power supply chip U1 is at zero volts. The charge required for the polarized capacitor EC5 to increase from 0 volts to 16 volts is Q = 4.7uF * 16V = 75.2uC. The polarized capacitor EC5 is charged by three 470K resistors connected in series: resistors R2, R10, and R12. The charging current is approximately i = 120V * 1.414 / (470K * 3) ≈ 120uA. The time for the polarized capacitor EC5 to charge to 16V is approximately t = 75.2 / 120 ≈ 626 milliseconds. That is, the startup time of the switching power supply circuit is approximately 626 milliseconds. Considering errors such as capacitor and chip operating voltage, in this embodiment, the delay time C is 800 milliseconds. Therefore, after detecting the mains power connection, it continues to execute at low power for 800 milliseconds to wait for the switching power supply circuit to start normally. If electrical components are used to restore the working state when the switching power supply circuit is not started, relays, water pumps, displays, etc. require hundreds of milliamps of current. The charge stored in the capacitor can only be discharged for tens of milliseconds, causing the voltage to drop rapidly. The control chip U3 is then reset, and the product cannot protect its original working state.

[0081] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control method for maintaining the original working state after a power outage and subsequent power restoration, characterized in that, Includes a zero-crossing detection module, an MCU module, a buck control module, an output driver module, and a low-speed clock; The zero-crossing detection module and the step-down control module are electrically connected to the mains power. The output terminal of the zero-crossing detection module is electrically connected to the MCU module. The step-down control module supplies power to the MCU module and the output drive module. The control terminal of the MCU module is electrically connected to the step-down control module and the output drive module. Specifically, it includes the following steps: The zero-crossing detection module detects the zero-crossing signal of the mains power. When the zero-crossing signal occurs, it outputs a low level to the MCU module. The internal timer of the MCU module counts the high level time. When a low level signal occurs, the timer is reset to zero. When the timer counts for a set value A, it is determined that the power is off. The MCU module shuts down the output drive module through the buck control module, entering a low-power mode; a low-speed clock starts up the MCU module at regular intervals, and the zero-crossing detection module detects the zero-crossing signal in real time. When the zero-crossing detection module outputs a low level within the timed wake-up time B, the low-speed clock is cleared and switched to the delay time C. When the delay time C is reached, the MCU module exits the low-power module and the output drive module is turned on through the buck control module, and the electrical appliance continues to work. When the low-speed clock timing exceeds the timer wake-up time B, the low-power module exits, and the MCU module switches its working state to the initial power-on state to wait for power-on; if it continues not to power on, the capacitor stored in the buck control module is consumed, and the MCU module is reset.

2. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The set value A is greater than 1 / 2 of the power grid cycle.

3. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The delay time C is greater than the startup time of the buck control module.

4. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The step-down control module includes a switching power supply circuit and a step-down power supply control circuit; The power input terminal of the switching power supply circuit is connected to the mains power, and the output terminal of the switching power supply circuit outputs a +12V voltage to the step-down power supply control circuit and the output drive module. The step-down power supply control circuit includes a voltage regulator chip U2, a MOSFET Q3, polarized capacitors EC6 and EC7, capacitor C7, and resistors R23, R24, R25, and R26. One end of resistor R23 and one end of resistor R24 ​​are electrically connected to the output terminal of the switching power supply circuit. The other end of resistor R23 is electrically connected to the other end of resistor R24, the positive terminal of polarized capacitor EC6, one end of capacitor C7, and the input terminal of voltage regulator chip U2. The output terminal of voltage regulator chip U2 is electrically connected to the positive terminal of polarized capacitor EC7, one end of resistor R25, and the source of MOSFET Q3, and outputs a +5V voltage to the MCU module and the zero-crossing detection module. The first control terminal of the MCU module is electrically connected to one end of resistor R26, the other end of resistor R26 is electrically connected to the gate of MOSFET Q3 and the other end of resistor R25, and the drain of MOSFET Q3 outputs a 5V voltage to the external power circuit. The ground terminal of the voltage regulator chip U2, the negative terminal of the polarized capacitor EC6, the negative terminal of the polarized capacitor EC7, and the other end of the capacitor C7 are all grounded.

5. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The zero-crossing detection module includes an optocoupler U4, a diode D7, a capacitor C13, a capacitor C14, and resistors R37, R38, and R39. The resistors R37 and R38 are connected in series between the live wire and pin 1 of the optocoupler U4. The negative terminal of the diode D7 is electrically connected to pin 1 of the optocoupler U4, and pin 2 of the optocoupler U4 is electrically connected to the positive terminal of the diode D7 and the neutral wire. Pin 4 of the optocoupler U4 is electrically connected to one end of resistor R39, one end of capacitor C13 and one end of capacitor C14, and is electrically connected to the MCU module as an output terminal. The buck control module outputs a +5V voltage to the other end of MOSFET R39. Pin 3 of the optocoupler U4, the other end of capacitor C13, and the other end of capacitor C14 are all grounded.

6. The control method for maintaining the original working state after power failure and power restoration according to claim 4, characterized in that: The MCU module includes a control chip U3 and a capacitor C9; The step-down control module outputs a +5V voltage to one end of capacitor C9 and pin 1 of control chip U3, and the other end of capacitor C9 is grounded; pin 5 of control chip U3 is electrically connected to the output of the zero-crossing detection module; pins 8, 9, 10 and 12 of control chip U3 are electrically connected to the output drive module; pin 15 of control chip U3 is electrically connected to one end of resistor R26.

7. The control method for maintaining the original working state after power failure and power restoration according to claim 6, characterized in that: The control chip U3 is model number TM56E0C6422S.

8. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The output drive module includes a MOSFET Q1, an interface CN5, a diode D1, a capacitor C3, and resistors R8, R13, R17, R18, and R19. The second control terminal of the MCU module is electrically connected to one end of resistor R8, and the third control terminal of the MCU module is electrically connected to one end of resistor R17 and one end of capacitor C3. The other end of resistor R17 is electrically connected to one end of resistor R18, one end of resistor R19, one end of resistor R13, and the source of MOSFET Q1; the other end of resistor R8 is electrically connected to the other end of resistor R13 and the gate of MOSFET Q1; the drain of MOSFET Q1 is electrically connected to the anode of diode D1 and pin 2 of interface CN5; the +12V output of the buck control module is supplied to pin 1 of interface CN5 and the cathode of diode D1; interface CN5 is connected to the power supply device. The other ends of capacitor C3, resistor R18, and resistor R19 are all grounded.

9. The control method for maintaining the original working state after power failure and power restoration according to claim 1, characterized in that: The output drive module also includes interface CN6, diode D2, MOSFET Q2, and resistors R9 and R14; The fourth control terminal of the MCU module is electrically connected to one end of resistor R9, and the other end of resistor R9 is electrically connected to the gate of MOSFET Q2 and one end of resistor R14; the drain of MOSFET Q2 is electrically connected to the anode of diode D2 and pin 2 of interface CN6; the output of the buck control module is +12V to pin 1 of interface CN6 and the cathode of diode D2; interface CN6 is connected to the power-consuming device. The other end of the resistor R14 and the source of the MOSFET Q2 are both grounded.

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