Power supply isolation protection circuit and microwave oven

Abstract

The utility model provides a power supply isolation protection circuit and a microwave oven. The circuit comprises a power supply module, a measurement module, a microcontroller, a fault indication and alarm module and a relay control module, one end of the power supply module is connected with a live line L and a zero line N of commercial power, and the other end of the power supply module is connected with the measurement module. The measurement module is connected with the microwave functional circuit through the relay control module; the measurement module, the fault indication and alarm module and the relay control module are all connected with the microcontroller; according to the power supply isolation protection circuit and the microwave oven, the structural arrangement of the protection circuit can be optimized, the abnormal condition processing efficiency of the protection circuit is improved, the abnormal condition processing flexibility and comprehensiveness of the protection circuit are enhanced, and the use safety of a user is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of microwave ovens, and more particularly, to a power isolation protection circuit and a microwave oven. Background Art

[0002] With the rapid development of modern means of transportation such as high-speed trains, airplanes, and ships, passengers' demand for convenient, efficient, and safe food has been increasing. On these means of transportation, microwave ovens, as a commonly used heating device, their safety and stability are particularly important. However, when facing a complex and changeable operating environment, the traditional microwave oven power supply system often faces challenges due to emergencies such as overload, undervoltage, overvoltage, short circuit, leakage, microwave leakage, and overheating, and may even cause safety accidents, thus threatening the stability of the power grid and the safety of passengers.

[0003] In the prior art, although some microwave ovens already have certain protection mechanisms, their protection effects are often unsatisfactory when facing special application scenarios such as high-speed trains, airplanes, and ships. The power supply environment in these scenarios is complex and changeable, posing higher requirements for the response speed, accuracy, and reliability of the power isolation protection circuit system.

[0004] Therefore, for microwave ovens on means of transportation such as high-speed trains, airplanes, and ships, it is particularly urgent to study how to implement a power isolation protection circuit for the microwave oven and then improve the emergency response ability of the circuit.

[0005] In patent CN104104059A, a safety protection circuit for a microwave oven is mentioned, including: a current detector for detecting the operating current of the heating device of the microwave oven; a first switch unit for controlling the input of AC mains power to the heating device, the first switch unit being connected between the AC mains power and the heating device; a safety protection switch unit connected between the AC mains power and the heating device; a controller connected to the current detector, the first switch unit, and the safety protection switch unit, wherein, after the controller controls the first switch unit to disconnect, if the current detector detects that the operating current is greater than a preset value, the controller controls the safety protection switch unit to cut off the AC mains power input to the heating device. It can prevent potential safety hazards caused by continuous heating of the heating device, but it fails to provide emergency protection for the power supply under different abnormal conditions. Summary of the Utility Model

[0006] In view of this, the present utility model aims to propose a power isolation protection circuit and a microwave oven to solve the technical defect problems existing in the prior art that the power supply system of the microwave oven has untimely response and imperfect protection mechanisms in special application environments such as high-speed railways, airplanes, and ships, including overload, undervoltage, overvoltage, short circuit, microwave leakage, and overheating. By doing so, the structure of the protection circuit is optimized, the efficiency of the protection circuit in dealing with abnormal situations is improved, the flexibility and comprehensiveness of the protection circuit in dealing with abnormalities are enhanced, the speed of the protection circuit in dealing with emergencies is increased, and the user's use safety is guaranteed.

[0007] To achieve the above object, the technical solution of the present utility model is realized as follows:

[0008] A power isolation protection circuit and a microwave oven according to the present utility model. The power isolation protection circuit includes a power supply module, a measurement module, a microcontroller, a fault indication and alarm module, and a relay control module. One end of the power supply module is respectively connected to the live wire L and the neutral wire N of the mains electricity, and the other end of the power supply module is connected to the measurement module. The measurement module is connected to the microwave function circuit through the relay control module, and the measurement module, the fault indication and alarm module, and the relay control module are all connected to the microcontroller.

[0009] Furthermore, at least one measurement module is provided.

[0010] Furthermore, the measurement module includes a current measurement module, a leakage measurement module, a voltage measurement module, a temperature measurement module, and a microwave measurement module. The current measurement module, the leakage measurement module, the voltage measurement module, the temperature measurement module, and the microwave measurement module are all connected to the microcontroller. The current measurement module is connected to the live wire L, and the leakage measurement module and the voltage measurement module are respectively connected to the power supply module.

[0011] Furthermore, the fault indication and alarm module includes a fault indication module and a fault warning module. One end of the fault indication module and the fault warning module is connected to the microcontroller, and the other end of the fault indication module and the fault warning module is respectively grounded.

[0012] Furthermore, the fault indication module includes a resistor and a light-emitting diode. One end of the resistor is connected to the microcontroller, and the other end of the resistor is connected to the positive electrode of the light-emitting diode. The negative electrode of the light-emitting diode is grounded.

[0013] Furthermore, at least one resistor and light-emitting diode are provided.

[0014] Furthermore, the fault warning module includes a twentieth resistor R20, a third triode Q3, and a buzzer B1. One end of the twentieth resistor R20 is connected to the P1 input terminal of the microcontroller, and the other end of the twentieth resistor R20 is grounded through the third triode Q3 and the buzzer B1 in sequence. The emitter of the third triode Q3 is connected to the DC power supply Vcc.

[0015] Further, the protection circuit further includes a fuse FU3 and a zero-ohm resistor R0. One end of the zero-ohm resistor R0 is connected to the microwave function circuit, and the other end of the zero-ohm resistor R0 is connected to the relay control module through the fuse FU3.

[0016] Further, the protection circuit further includes a thirteenth capacitor C13. One end of the thirteenth capacitor C13 is respectively connected to the VCC input terminal of the microcontroller and the DC power supply Vcc, and the other end of the thirteenth capacitor C13 is grounded.

[0017] A microwave oven, the microwave oven includes the power isolation protection circuit as described above, and the power isolation protection circuit is arranged inside the microwave oven.

[0018] Compared with the prior art, the power isolation protection circuit and the microwave oven of the present utility model have the following beneficial effects:

[0019] The setting of the circuit optimizes the structural setting of the protection circuit, improves the efficiency of the protection circuit in dealing with abnormal situations, enhances the flexibility and comprehensiveness of the protection circuit in dealing with abnormalities, increases the speed of the circuit in dealing with emergencies, and ensures the safety of users during use. Description of the Drawings

[0020] The drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation of the present utility model. In the drawings:

[0021] Figure 1 It is a schematic diagram of the overall frame structure of the power isolation protection circuit;

[0022] Figure 2 It is a schematic diagram of the installation positions of the antennas when multiple microwave antennas are provided;

[0023] Figure 3 It is a schematic diagram of the schematic circuit diagram of the power isolation protection circuit.

[0024] Description of the reference numerals in the drawings: 100, power supply module; 200, measurement module; 201, current measurement module; 202, leakage measurement module; 203, voltage measurement module; 204, temperature measurement module; 205, microwave measurement module; 300, microcontroller; 400, fault indication and alarm module; 401, fault indication module; 402, fault early warning module; 500, relay control module. Detailed Embodiments

[0025] The utility model concepts of the present disclosure will hereinafter be described using terms commonly employed by those skilled in the art to convey the substance of their work to other artisans in the field. However, these utility model concepts may be embodied in many different forms and should not be construed as limited to the embodiments described herein.

[0026] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments may be combined with each other.

[0027] The present utility model will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0028] This embodiment is directed to a microwave oven. Similar to a conventional microwave oven, the overall structure is composed of a metal mesh, a transformer, and a magnetron.

[0029] In order to solve the technical defect problems existing in the prior art that the microwave oven power supply system has untimely response and imperfect protection mechanisms in special application environments such as high-speed trains, airplanes, and ships, such as overload, undervoltage, overvoltage, short circuit, microwave leakage, and overheating; this embodiment proposes a power isolation protection circuit and a microwave oven. The power isolation protection circuit includes a power supply module 100, a measurement module 200, a microcontroller 300, a fault indication and alarm module 400, and a relay control module 500. One end of the power supply module 100 is respectively connected to the live wire L and the neutral wire N of the mains, and the other end of the power supply module 100 is connected to the measurement module 200. The measurement module 200 is connected to the microwave function circuit through the relay control module 500, and the measurement module 200, the fault indication and alarm module 400, and the relay control module 500 are all connected to the microcontroller 300. The power supply module 100 is responsible for converting the mains alternating current into a stable low-voltage direct current to supply power to all the measurement modules 200, the microcontroller 300 of the protection circuit, the relay control module 500, and the fault indication and alarm module 400.

[0030] Through the setting of each module, the structural setting of the protection circuit can be optimized, the efficiency of the protection circuit in dealing with abnormal situations can be improved, the flexibility and comprehensiveness of the protection circuit in dealing with abnormalities can be enhanced, the speed of the circuit in dealing with emergencies can be increased, and the use safety of users can be guaranteed. In addition, the coordinated setting of each module is also beneficial to improving the fast response ability of the circuit. When an abnormal situation is detected, the connection between the microwave oven and the power grid can be quickly cut off, effectively preventing the expansion of the fault, avoiding the possible response delay problem in the traditional protection mechanism, ensuring the timeliness and effectiveness of the protection action, and reducing the use and maintenance costs.

[0031] The power supply module 100 includes a fuse FU1, a fuse FU2, a varistor RV1, a varistor RV2, a varistor RV3, a safety capacitor CV1, a safety capacitor CV2, a safety capacitor CV3, a gas discharge tube G1, a common mode inductor CM, and a power supply. The positive and negative electrodes on the current input side of the fuse FU1 are respectively connected to the live wire L and the neutral wire N of the mains power supply. The positive electrode on the current output side of the fuse FU1 is respectively connected to one end of the varistor RV1, the safety capacitor CV1, the safety capacitor CV3, the varistor RV3, and the positive electrode on the input side of the common mode inductor CM. The other end of the varistor RV1 is respectively connected to one end of the gas discharge tube G1 and the varistor RV2. The other end of the varistor RV2 is grounded to the ground wire PE. The other end of the safety capacitor CV1 is respectively connected to the ground wire PE and one end of the safety capacitor CV2. The other ends of the varistor RV2, the safety capacitor CV2, the safety capacitor CV3, the varistor RV3, and the negative electrode on the input side of the common mode inductor CM are all connected to the negative electrode on the current output side of the fuse FU1. The positive and negative electrodes on the output side of the common mode inductor CM are respectively connected to the positive and negative electrodes on the output side of the measurement module 200 and the fuse FU2. The positive electrode on the input side of the fuse FU2 is connected to the DC power supply Vcc through the power supply, and the negative electrode on the input side of the fuse FU2 is grounded through the power supply.

[0032] Through the settings of the fuse FU1 and the fuse FU2, short-circuit protection of the main circuit and the protection circuit can be respectively achieved, which is convenient for circuit maintenance. The safety capacitors CV1, CV2, and CV3 are all safety capacitors. The safety capacitors CV1 and CV2 are used to filter out common mode interference. The safety capacitor CV3 is used to filter out differential mode interference between the phase line and the neutral wire N, and prevent high-frequency interference signals of the current circuit from leaking out through the power line, thereby interfering with other electrical equipment. RV1, RV2, and RV3 are all varistors. The combined settings of RV1, RV2, RV3, and the gas discharge tube G1 are used for overvoltage and lightning protection of the main circuit. When an overvoltage appears in the circuit, the varistor will quickly conduct and clamp the voltage. At this time, if the overvoltage is still very high and exceeds the ignition voltage of the gas discharge tube, the gas discharge tube will conduct and discharge the current to the ground, further protecting the circuit. The common mode inductor CM is used to suppress common mode interference, play the roles of current limiting, suppressing high-frequency interference, and smoothing filtering, which helps to protect the components in the circuit from impact and damage, and improve the stability and reliability of the circuit.

[0033] At least one measurement module 200 is provided. The measurement module 200 includes a current measurement module 201, a leakage point measurement module 202, a voltage measurement module 203, a temperature measurement module 204, and a microwave measurement module 205; the current measurement module 201, the leakage point measurement module 202, the voltage measurement module 203, the temperature measurement module 204, and the microwave measurement module 205 are all connected to the microcontroller 300. The current measurement module 201 is connected to the live wire L, and the leakage point measurement module 202 and the voltage measurement module 203 are respectively connected to the positive and negative electrodes of the output side of the common mode inductor CM in the power supply module 100.

[0034] By setting measurement modules with different functions, a highly integrated protection mechanism can be achieved. And by integrating multiple protection functions such as overload, undervoltage, overvoltage, short circuit, microwave leakage, and overheating of temperature, under the action of high-precision sensors and fast-response control circuits, real-time monitoring of faults caused by different conditions can be realized. Furthermore, it is beneficial to achieve comprehensive monitoring and timely protection of the working state of the microwave oven circuit, significantly improving the safety and reliability of the system.

[0035] The current measurement module 201 includes a current sensor U2, a first capacitor C1, a first resistor R1, and a second resistor R2; the current sensor U2 is used to convert alternating current into direct current voltage for output; after being divided by the first resistor R1 and the second resistor R2, it is sent to the AD input terminal of the microcontroller 300 in the protection circuit. Among them, the pin VCC of the current sensor U2 is connected in parallel with one end of the first capacitor C1 and then connected to the DC power supply Vcc, and the other end of the first capacitor C1 is connected in parallel with the pin GND of the current sensor U2 and grounded; the positive electrode of the output side of the common mode inductor CM is connected to the pin IN+ of the current sensor U2, and the pin IN- of the current sensor U2 is connected to the leakage point measurement module 202; the pin OUT of the current sensor U2 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is respectively connected to one end of the second resistor R2 and the ADC1 input terminal of the microcontroller 300; the other end of the second resistor R2 is grounded. Among them, the current sensor U2 is a Hall current sensor.

[0036] By setting the current measurement module 201, the detection of voltage changes in the circuit can be effectively realized, which is beneficial to improving the safety of the circuit and enhancing the comprehensiveness of real-time state monitoring of the circuit. It improves the safety of personnel.

[0037] The leakage point measurement module 202 includes a current transformer CT, a first diode D1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and a leakage detection chip U3. The input side of the current transformer CT is respectively connected to the negative electrode of the output side of the common mode inductor CM and the pin IN- of the current sensor U2; one end of the output side of the current transformer CT is respectively connected to the input ends of the first diode D1, the third resistor R3, and the fourth resistor R4, and the other end of the output side of the current transformer CT is respectively connected to one end of the first diode D1, the third resistor R3, the fourth capacitor C4, and the fifth resistor R5. The other end of the fourth resistor R4 is respectively connected to one end of the third capacitor C3 and the pin IN2 of the leakage detection chip U3. The other end of the fifth resistor R5 is respectively connected to one end of the second capacitor C2, the other end of the third capacitor C3, and the pin IN1 of the leakage detection chip U3. The other ends of the second capacitor C2 and the fourth capacitor C4 are both grounded; the pin OA of the leakage detection chip U3 is grounded through the fifth capacitor C5; the pin LV of the leakage detection chip U3 is respectively connected to one end of the sixth capacitor C6 and the ADC2 input end of the microcontroller 300. The other end of the sixth capacitor C6 is connected in parallel with the pin VTR of the leakage detection chip U3 and grounded; the pin VS of the leakage detection chip U3 is respectively connected to the DC power supply Vcc and one end of the seventh capacitor C7, and the other end of the seventh capacitor C7 is grounded. Among them, the current transformer CT is a residual current transformer.

[0038] Through the setting of the residual current transformer CT, under normal circumstances, the currents of the phase line and the neutral line N are balanced, and there is no induced electromotive force in the secondary side coil of the CT; when a leakage occurs, an induced current proportional to the leakage current is generated in the secondary circuit of the secondary side coil of the CT. The larger the leakage current, the greater the induced electromotive force in the secondary winding. U3 differentially amplifies the induced electromotive force for the protection circuit microcontroller 300 to identify.

[0039] The voltage measurement module 203 includes a voltage transformer VT, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth resistor R6, a seventh resistor R7, a zener diode Z1, an eighth capacitor C8, and a ninth capacitor C9. The positive and negative poles of the input side of the voltage transformer VT are respectively connected to the positive and negative poles of the output side of the common mode inductor CM; the positive pole of the output side of the voltage transformer VT is respectively connected to the positive pole of the fourth diode D4 and the negative pole of the fifth diode D5, and the negative pole of the output side of the voltage transformer VT is respectively connected to the positive pole of the second diode D2 and the negative pole of the third diode D3. After the negative poles of the second diode D2 and the fourth diode D4 are connected in parallel, they are respectively connected to one end of the eighth capacitor C8, the ninth capacitor C9, and the sixth resistor R6. The other end of the sixth resistor R6 is respectively connected to one end of the seventh resistor R7, the zener diode Z1, and the ADV input terminal of the microcontroller 300. The positive poles of the third diode D3 and the fifth diode D5, the other ends of the eighth capacitor C8, the ninth capacitor C9, the seventh resistor R7, and the zener diode Z1 are connected in parallel and then grounded. Among them, the second diode D2, the third diode D3, the fourth diode D4, and the fifth diode D5 are all rectifier diodes. The second diode D2, the third diode D3, the fourth diode D4, and the fifth diode D5 form a full-bridge rectifier circuit. The eighth capacitor C8 and the ninth capacitor C9 are used for filtering. The sixth resistor R6 and the seventh resistor R7 are used for voltage division.

[0040] Through the setting of VT, the high-voltage alternating current of the power grid can be converted into low-voltage alternating current. After passing through the full-bridge rectifier circuit composed of the rectifier diodes D2, D3, D4, and D5, it becomes a pulsating DC voltage, and then after filtering by the capacitors C8 and C9, it is output as a low-voltage smooth DC. The output voltage is: V2 = 1.2V1, where V1 refers to the voltage value of the output side of the voltage transformer VT, and V2 refers to the voltage at the connection between the fourth diode D4 and the eighth capacitor C8.

[0041] Finally, it is sent to the protection circuit U1, that is, the ADV input port of the microcontroller 300, for measurement after voltage division by the resistors R6 and R7. The presence of the zener diode Z1 prevents its output voltage from being too high and damaging the microcontroller 300.

[0042] Under normal circumstances, the output voltage V3 at the connection between the sixth resistor R6 and the seventh resistor R7 is:

[0043]

[0044] When the output voltage is greater than the preset zener voltage value of Z1, Z1 exerts a voltage stabilizing effect, limiting the maximum output voltage to the zener voltage value VZ1 of Z1.

[0045] The output voltage V3 is positively correlated with the power grid voltage. When the power grid voltage undergoes undervoltage or overvoltage conditions, U1 can identify them by monitoring the voltage of V1.

[0046] The temperature measurement module 204 includes a thermistor RT, an eighth resistor R8, a ninth resistor R9, and a tenth capacitor C10; one ends of the thermistor RT and the eighth resistor R8 are connected in parallel and then connected to the DC power supply Vcc, and the other ends of the thermistor RT and the eighth resistor R8 are connected in parallel with one ends of the ninth resistor R9 and the tenth capacitor C10 and then connected to the ADT input end of the microcontroller 300; the other ends of the ninth resistor R9 and the tenth capacitor C10 are connected in parallel and then grounded. Among them, the thermistor RT is a negative temperature coefficient thermistor.

[0047] After RT and R8 are connected in parallel and then in series with R9 for voltage division and sent to the ADT input of the protection circuit microcontroller 300, the magnitude of the voltage V4 at the connection between the thermistor RT and the tenth capacitor C10 is as follows:

[0048]

[0049] When the temperature rises, the resistance of RT decreases and the output of V4 increases; when the temperature drops, the resistance of RT increases and the output of V4 decreases.

[0050] The microwave measurement module 205 includes a microwave antenna ANT, an eleventh capacitor C11, a twelfth capacitor C12, a tenth resistor R10, a potentiometer RP, and a radio frequency detector U4; one end of the microwave antenna ANT is grounded, and the other end of the microwave antenna ANT is connected to the pin RFIN of the radio frequency detector U4 through the eleventh capacitor C11. The pins GND and VOS of the radio frequency detector U4 are connected in parallel and grounded, and the pin VCC of the radio frequency detector U4 is respectively connected to the DC power supply Vcc and one end of the twelfth capacitor C12, and the other end of the twelfth capacitor C12 is grounded; the pin VM of the radio frequency detector U4 is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected in parallel with the pin VOUT of the radio frequency detector U4 and then connected to one end of the potentiometer RP, and the other end of the potentiometer RP is connected to the ADW input end of the microcontroller 300. Among them, the microwave antenna ANT is arranged at the door gap of the microwave oven. At least one microwave antenna ANT is provided. When multiple microwave antennas ANT are provided, the multiple microwave antennas ANT are installed in parallel at different positions within the door gap of the microwave oven.

[0051] Since the inner cavity of the microwave oven is a sealed metal, it can ensure that the microwave is reflected inside the cavity and is not easily leaked to the outside. The potential positions of microwave leakage are mainly the door gap positions. ANT is installed at the door gap position of the microwave oven. Generally, one or more positions can be selected for parallel installation, and its installation positions are as Figure 2As shown, the radio frequency detector U4 connects the microwave antenna ANT to the input port RFIN of U4 through a coaxial cable. C11 is responsible for filtering out low-frequency signals. After being amplified by the detector in cooperation with R10 and RP, the signal is sent to the ADW input end of the protection circuit microcontroller 300. The potentiometer RP is responsible for adjusting the gain.

[0052] The fault indication and alarm module 400 includes a fault indication module 401 and a fault warning module 402. One end of the fault indication module 401 and the fault warning module 402 are both connected to the microcontroller 300, and the other ends of the fault indication module 401 and the fault warning module 402 are both grounded respectively. The fault indication module 401 is used for light source indication alarm; the fault warning module 402 is used for sound source indication alarm. The fault indication module 401 includes a resistor and a light-emitting diode. One end of the resistor is connected to the microcontroller 300, and the other end of the resistor is connected to the positive pole of the light-emitting diode. The negative pole of the light-emitting diode is grounded. At least one resistor and light-emitting diode are provided, which are used to set multiple fault indicator lights according to different needs. The fault warning module 402 includes a twentieth resistor R20, a third triode Q3, and a buzzer B1. One end of the twentieth resistor R20 is connected to the P1 input end of the microcontroller 300, and the other end of the twentieth resistor R20 is grounded through the third triode Q3 and the buzzer B1 in sequence. The emitter of the third triode Q3 is connected to the DC power supply Vcc. Among them, the third triode Q3 is a PNP triode, and the buzzer B1 is an active buzzer.

[0053] In this embodiment, six resistors and six light-emitting diodes are provided. The resistors include the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, and the nineteenth resistor R19; the light-emitting diodes include the seventh diode D7, the eighth diode D8, the ninth diode D9, the tenth diode D10, the eleventh diode D11, and the twelfth diode D12; one end of the fourteenth resistor R14 is connected to the P1 input end of the microcontroller 300, and the other end of the fourteenth resistor R14 is grounded through the seventh diode D7, and D7 is the normal circuit indicator; one end of the fifteenth resistor R15 is connected to the P1 input end of the microcontroller 300, and the other end of the fifteenth resistor R15 is grounded through the eighth diode D8, and D8 is the voltage fault indicator; one end of the sixteenth resistor R16 is connected to the P1 input end of the microcontroller 300, and the other end of the sixteenth resistor R16 is grounded through the ninth diode D9, and D9 is the circuit fault indicator; one end of the seventeenth resistor R17 is connected to the P1 input end of the microcontroller 300, and the other end of the seventeenth resistor R17 is grounded through the tenth diode D10, and D10 is the temperature fault indicator; one end of the eighteenth resistor R18 is connected to the P1 input end of the microcontroller 300, and the other end of the eighteenth resistor R18 is grounded through the eleventh diode D11, and D11 is the microwave leakage indicator; one end of the nineteenth resistor R19 is connected to the P1 input end of the microcontroller 300, and the other end of the nineteenth resistor R19 is grounded through the twelfth diode D12, and D12 is the circuit function fault indicator.

[0054] Through the setting of each component in the fault indication and alarm module 400, when the circuit is working normally, D7 is lit and the rest of the LEDs are extinguished; when voltage faults, current faults, temperature faults, microwave leakage faults, and microwave oven function faults occur in the circuit respectively, the microcontroller 300 controls D8, D9, D10, D11, and D12 to be lit respectively, and controls the buzzer B1 to sound an alarm.

[0055] The relay control module 500 includes a first triode Q1, a second triode Q2, a twelfth resistor R12, a thirteenth resistor R13, a sixth diode D6, an electromagnetic relay K1, and a solid-state relay K2; the switch of the electromagnetic relay K1 is arranged between the positive and negative poles of the output side of the common-mode inductor CM, and one end of the switch of the electromagnetic relay K1 far from the positive pole of the output side of the common-mode inductor CM is connected to the microwave function circuit through the solid-state relay K2; one end of the coil of the electromagnetic relay K1 is respectively connected to the collector of the first triode Q1 and the negative pole of the sixth diode D6, the emitter of the first triode Q1 is connected to the DC power supply Vcc, and the base of the first triode Q1 is connected to the RL1 input end of the microcontroller 300 through the twelfth resistor R12; the other end of the coil of the electromagnetic relay K1, the positive pole of the sixth diode D6, and the negative pole of the solid-state relay K2 are connected in parallel and then grounded; the positive pole of the solid-state relay K2 is sequentially connected to the RL2 input end of the microcontroller 300 through the second triode Q2 and the thirteenth resistor R13. Among them, both the first triode Q1 and the second triode Q2 are PNP triodes.

[0056] Through the setting of K1, the function of physically isolating the circuit can be achieved. Since K2 has the advantage of fast action switching speed, through the setting of K2, the timeliness of power cut-off can be ensured, and the protection of the power supply can be improved. In addition, when the RL1 and RL2 terminals of the microcontroller 300 in the protection circuit output high level, Q1 and Q2 are cut off, and the relays K1 and K2 are turned off, and the power supply to the microwave function circuit is cut off; when RL1 and RL2 output low level, Q1 and Q2 are turned on, and the relays K1 and K2 are connected, and power is supplied to the microwave function circuit.

[0057] The INTO interrupt port of the microcontroller 300 is connected to the controller in the microwave function circuit for real-time monitoring of the fault conditions in the microwave function circuit; when a serious fault occurs in the microwave function circuit, the controller of the microwave function circuit sends an interrupt signal to the INTO interrupt port of the microcontroller 300.

[0058] The protection circuit further includes a fuse FU3 and a zero-ohm resistor R0; one end of the zero-ohm resistor R0 is connected to the microwave function circuit, and the other end of the zero-ohm resistor R0 is connected to the solid-state relay K2 in the relay control module 500 through the fuse FU3. The fuse FU3 is used to achieve short-circuit protection for the microwave function circuit, and the zero-ohm resistor R0 is used to facilitate circuit maintenance. The protection circuit further includes a thirteenth capacitor C13, one end of the thirteenth capacitor C13 is respectively connected to the VCC input end of the microcontroller 300 and the DC power supply Vcc, and the other end of the thirteenth capacitor C13 is grounded.

[0059] A microwave oven, the microwave oven includes the described power isolation protection circuit. The power isolation protection circuit is arranged in the microwave oven.

[0060] In the present utility model, for any microwave oven, it may include a power isolation protection circuit structure described in this embodiment. Based on the relevant structures and assembly relationships of the microwave measurement module 205 and the fault indication and alarm module 400 provided in this embodiment, the microwave oven further includes conventional components such as a power isolation protection circuit and a microwave oven. Since they are all prior arts, no further elaboration will be provided here.

[0061] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A power isolation protection circuit, characterized in that, It includes a power supply module (100), a measurement module (200), a microcontroller (300), a fault indication and alarm module (400), and a relay control module (500); one end of the power supply module (100) is respectively connected to the live wire L and the neutral wire N of the mains, and the other end of the power supply module (100) is connected to the measurement module (200); the measurement module (200) is connected to the microwave function circuit through the relay control module (500), and the measurement module (200), the fault indication and alarm module (400), and the relay control module (500) are all connected to the microcontroller (300).

2. The power supply isolation protection circuit according to claim 1, characterized in that At least one measurement module (200) is provided.

3. The power isolation protection circuit according to claim 2, wherein, The measurement module (200) includes a current measurement module (201), a leakage measurement module (202), a voltage measurement module (203), a temperature measurement module (204), and a microwave measurement module (205); the current measurement module (201), the leakage measurement module (202), the voltage measurement module (203), the temperature measurement module (204), and the microwave measurement module (205) are all connected to the microcontroller (300), the current measurement module (201) is connected to the live wire L, and the leakage measurement module (202) and the voltage measurement module (203) are respectively connected to the power supply module (100).

4. A power isolation protection circuit according to claim 1, characterized in that, The fault indication and alarm module (400) includes a fault indication module (401) and a fault warning module (402), one end of the fault indication module (401) and the fault warning module (402) are both connected to the microcontroller (300), and the other end of the fault indication module (401) and the fault warning module (402) are both grounded respectively.

5. A power isolation protection circuit according to claim 4, characterized in that, The fault indication module (401) includes a resistor and a light-emitting diode, one end of the resistor is connected to the microcontroller (300), the other end of the resistor is connected to the positive electrode of the light-emitting diode, and the negative electrode of the light-emitting diode is grounded.

6. The power supply isolation protection circuit according to claim 5, wherein At least one resistor and light-emitting diode are provided.

7. A power isolation protection circuit according to claim 4, characterized in that, The fault warning module (402) includes a twentieth resistor R20, a third triode Q3, and a buzzer B1; one end of the twentieth resistor R20 is connected to the P1 input terminal of the microcontroller (300), the other end of the twentieth resistor R20 is grounded through the third triode Q3 and the buzzer B1 in sequence, and the emitter of the third triode Q3 is connected to the DC power supply Vcc.

8. The power isolation protection circuit according to claim 1, wherein The protection circuit further includes a fuse FU3 and a zero-ohm resistor R0; one end of the zero-ohm resistor R0 is connected to the microwave function circuit, and the other end of the zero-ohm resistor R0 is connected to the relay control module (500) through the fuse FU3.

9. The power isolation protection circuit according to claim 1, characterized in that, The protection circuit further includes a thirteenth capacitor C13, one end of the thirteenth capacitor C13 is respectively connected to the VCC input terminal of the microcontroller (300) and the DC power supply Vcc, and the other end of the thirteenth capacitor C13 is grounded.

10. A microwave oven, characterized in that, The microwave oven includes a power supply isolation protection circuit according to any one of claims 1-9, and the power supply isolation protection circuit is provided inside the microwave oven.

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