Microwave control circuit and vehicle-mounted microwave oven

Abstract

The utility model provides a microwave control circuit and a vehicle-mounted microwave oven, the circuit comprises a microwave drive circuit, a silicon controlled rectifier T1, a protection circuit and an isolation circuit, the microwave drive circuit and the isolation circuit are connected with a transformer L through the silicon controlled rectifier T1 and the protection circuit in sequence, and one end, far away from the silicon controlled rectifier T1, of the microwave drive circuit and one end, far away from the silicon controlled rectifier T1, of the isolation circuit are connected with a single-chip microcomputer; according to the microwave control circuit and the vehicle-mounted microwave oven, the anti-vibration performance of the relay in the vehicle-mounted microwave oven can be effectively improved, the reliability and the safety of the vehicle-mounted microwave oven are higher, the impact on the relay in the microwave oven when the microwave is started and closed is avoided, the adhesion of a relay contact is prevented, and the service life of the microwave oven is prolonged. Therefore, the use stability of the vehicle-mounted microwave oven is enhanced, and the service life of the vehicle-mounted microwave oven is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle-mounted microwave ovens, and in particular to a microwave control circuit and a vehicle-mounted microwave oven. Background Art

[0002] At present, traditional household microwave ovens widely use electromagnetic relays as switches to control microwaves in microwave ovens. The single chip microcomputer controls the closing of relay contacts to start the microwaves, and the disconnection of relay contacts to stop the microwaves. The traditional control method can be applied to vehicle-mounted microwave ovens to control microwaves, but the traditional relays have great risks in terms of reliability such as vibration resistance, especially in vehicle-mounted environments. The risk of failure is high. At the same time, due to the large starting current at the moment of microwave starting, ordinary vehicle-grade relays cannot withstand such a large starting current. Therefore, studying how to improve the stability and reliability of microwave ovens used in vehicle environments is one of the problems that need to be solved urgently.

[0003] In patent CN203964054U, a vehicle-mounted microwave oven is mentioned, including a cavity; a magnetron that generates microwaves and feeds them into the cavity; a power supply device, which includes: a DC booster, which converts DC power of a first voltage into DC power of a second voltage; a single-pole double-throw control switch; an AC / DC converter, which is connected to the DC booster and the AC power supply through a single-pole double-throw control switch, respectively, and the AC / DC converter converts DC power of a second voltage into DC power of a third voltage to supply the magnetron, or converts AC power output from the AC power supply into DC power of a third voltage to supply the magnetron; a control device, which is connected to the single-pole double-throw control switch, and the control device controls the single-pole double-throw control switch to select the DC booster or the AC power supply to be connected to the AC / DC converter. Although the vehicle-mounted microwave oven can realize vehicle-mounted DC power supply without an inverter, which reduces the cost, volume and weight, and is easy to carry, the setting of the microwave oven does not solve the problem that the relay in the microwave oven has a great risk in terms of reliability such as anti-vibration. Utility Model Content

[0004] In view of this, the utility model aims to propose a microwave control circuit and a vehicle-mounted microwave oven, so as to solve the problem in the prior art that the microwave oven installed in the car using the traditional control method has low vibration resistance, reliability, safety and stability of the internal relay, and also faces the problem that the starting current at the moment of microwave starting is large and ordinary automotive-grade relays are difficult to withstand such a large starting current; thereby effectively improving the vibration resistance of the relay in the vehicle-mounted microwave oven, making the vehicle-mounted microwave oven more reliable and safer, avoiding the impact on the relay in the microwave oven when the microwave is started and shut down, preventing the relay contacts from sticking, thereby enhancing the stability of the vehicle-mounted microwave oven and extending the service life of the vehicle-mounted microwave oven.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] The utility model relates to a microwave control circuit and a vehicle-mounted microwave oven. The microwave control circuit comprises a microwave driving circuit, a thyristor T1, a protection circuit and an isolation circuit. The microwave driving circuit and the isolation circuit are connected to a transformer L through the thyristor T1 and the protection circuit in sequence. The ends of the microwave driving circuit and the isolation circuit away from the thyristor T1 are connected to a single-chip microcomputer.

[0007] Furthermore, the single chip microcomputer includes a first serial port IO1 and a second serial port IO2, the first serial port IO1 is connected to the microwave driving circuit, and the second serial port IO2 is connected to the isolation circuit.

[0008] Furthermore, the microwave driving circuit includes a first resistor R1, a second resistor R2, a first transistor Q1, and a relay RL1. The first resistor R1, the first transistor Q1, the second resistor R2, the relay RL1, and the thyristor T1 are connected in sequence, and one end of the first resistor R1 away from the first transistor Q1 is connected to the microcontroller.

[0009] Further, the first serial port IO1 is electrically connected to the base of the first transistor Q1 through the first resistor R1, the collector of the first transistor Q1 is connected to the first power supply VDD through the second resistor R2 and the coil of the relay RL1 in sequence, and the emitter of the first transistor Q1 is grounded; one end of the contact switch of the relay RL1 is respectively connected to the live wire AC-L of the AC power supply, the anode of the thyristor T1, the isolation circuit, and the protection circuit, and the other end of the contact switch of the relay RL1 is respectively connected to the cathode of the thyristor T1, the protection circuit, and the current input end of the transformer L; the current output end of the transformer L is connected to the neutral wire AC-N of the AC power supply.

[0010] Furthermore, the microwave driving circuit further includes a freewheeling diode D1 , which is arranged in parallel at both ends of the coil of the relay RL1 .

[0011] Further, the anode of the freewheeling diode D1 is connected to the DC current output terminal of the coil of the relay RL1 , and the cathode of the freewheeling diode D1 is connected to the DC current input terminal of the coil of the relay RL1 .

[0012] Furthermore, the isolation circuit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, and an optocoupler U1. The second serial port IO2 is connected to the base of the second transistor Q2 through the third resistor R3, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to pin 2 of the optocoupler U1; pin 1 of the optocoupler U1 is connected to the second power supply VCC through the fourth resistor R4, pin 3 of the optocoupler U1 is connected to the control electrode of the thyristor T1, and pin 4 of the optocoupler U1 is connected to the anode of the thyristor T1 through the fifth resistor R5.

[0013] Furthermore, the protection circuit includes a capacitor C1, a sixth resistor R6, and a varistor VR1. The current input end of the sixth resistor R6 is respectively connected to the anode of the thyristor T1, the current input end of the varistor VR1, and the live wire AC-L of the AC power supply. The current output end of the sixth resistor R6 is respectively electrically connected to the cathode of the thyristor T1, the current output end of the varistor VR1, and the current input end of the transformer L through the capacitor C1.

[0014] Furthermore, at least one single chip microcomputer is provided.

[0015] A vehicle-mounted microwave oven, the microwave oven applying the microwave control circuit, the microwave control circuit being arranged inside the vehicle-mounted microwave oven.

[0016] Compared with the prior art, the microwave control circuit and vehicle-mounted microwave oven described in the utility model have the following beneficial effects:

[0017] By setting the control circuit, the vibration resistance of the relay in the vehicle-mounted microwave oven can be effectively improved, so that the reliability and safety of the vehicle-mounted microwave oven are higher, and the impact on the relay in the microwave oven when the microwave is started and shut down is avoided, and the relay contacts are prevented from sticking, thereby enhancing the use stability of the vehicle-mounted microwave oven and extending the service life of the vehicle-mounted microwave oven. It can also prevent the control circuit from passing a large current for a long time, thereby causing serious heating problems, thereby greatly improving the reliability of the vehicle-mounted microwave oven product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 Schematic diagram of microwave control driving circuit.

[0020] Explanation of the accompanying drawings: 1. microwave driving circuit; 2. protection circuit; 3. isolation circuit. DETAILED DESCRIPTION

[0021] The following will use the terms commonly used by those skilled in the art to convey the essence of their work to other technical personnel in the art to describe the utility model concepts of the present disclosure. However, these utility model concepts can be embodied in many different forms and should not be considered as limited to the embodiments described herein.

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0024] This embodiment is directed to a vehicle-mounted microwave oven control circuit, and is similar to a conventional vehicle-mounted microwave oven control circuit in that the overall structure is composed of a cooking cavity, wires, and a magnetron.

[0025] In the prior art, conventional household microwave ovens widely use electromagnetic relays as switches to achieve control of microwaves in the microwave ovens. The microwaves are started by closing the relay contacts controlled by a single-chip microcomputer, and stopped by opening the relay contacts. However, conventional relays have great risks in terms of reliability such as vibration resistance, especially in vehicle-mounted environments, where the risk of failure is high. At the same time, due to the large starting current at the moment of microwave starting, ordinary automotive-grade relays are unable to withstand such a large starting current.

[0026] In order to solve the problem that the microwave oven installed in the car using the traditional control method in the prior art has low vibration resistance, reliability, safety and stability of the internal relay, and also faces the problem that the starting current at the moment of microwave starting is large and the ordinary automotive-grade relay is difficult to withstand such a large starting current; this embodiment proposes a microwave control circuit and a vehicle-mounted microwave oven, the microwave control circuit includes a microwave drive circuit 1, a thyristor T1, a protection circuit 2, and an isolation circuit 3, the microwave drive circuit 1 and the isolation circuit 3 are connected to the transformer L through the thyristor T1 and the protection circuit 2 in turn, and the ends of the microwave drive circuit 1 and the isolation circuit 3 away from the thyristor T1 are connected to the single-chip microcomputer; under the signal of the single-chip microcomputer, the transformer L is turned on and off through the coordinated setting between the microwave drive circuit 1, the thyristor T1 and the protection circuit 2, thereby realizing the start and stop of the microwave.

[0027] By setting the control circuit, the vibration resistance of the relay in the vehicle-mounted microwave oven can be effectively improved, so that the reliability and safety of the vehicle-mounted microwave oven are higher, and it is also beneficial to enhance the use stability of the vehicle-mounted microwave oven and extend the service life of the vehicle-mounted microwave oven.

[0028] At least one single-chip microcomputer is provided. The single-chip microcomputer includes a first serial port IO1 and a second serial port IO2, wherein the first serial port IO1 is connected to the microwave driving circuit 1, and the second serial port IO2 is connected to the isolation circuit 3, and is used to control the microwave driving circuit 1 and the isolation circuit 3 with corresponding command signals through different IO input and output serial ports of the single-chip microcomputer, thereby realizing control of microwave startup.

[0029] Issuing instructions to the control circuit separately through the dual IO ports of the single-chip microcomputer is beneficial to improving the stability of the control circuit, avoiding the problem of limited microwave starting accuracy caused by instruction stacking or duplication, and further helping to improve the reliability and safety of the control circuit.

[0030] The microwave driving circuit 1 comprises a first resistor R1, a second resistor R2, a first transistor Q1, and a relay RL1. The first resistor R1, the first transistor Q1, the second resistor R2, the relay RL1, and the thyristor T1 are connected in sequence, and one end of the first resistor R1 away from the first transistor Q1 is connected to the single chip computer. Specifically, the first serial port IO1 is electrically connected to the base of the first transistor Q1 through the first resistor R1, and the collector of the first transistor Q1 is connected to the first power supply VDD through the second resistor R2 and the coil of the relay RL1 in sequence. The voltage value of the first power supply VDD is set as required, and the emitter of the first transistor Q1 is grounded; one end of the contact switch of the relay RL1 is respectively connected to the live wire AC-L of the AC power supply, the anode of the thyristor T1, the isolation circuit 3, and the protection circuit 2, and the other end of the contact switch of the relay RL1 is respectively connected to the cathode of the thyristor T1, the protection circuit 2, and the current input end of the transformer L; the current output end of the transformer L is connected to the neutral wire AC-N of the AC power supply. In this embodiment, the voltage value of the first power supply VDD is 12V, and the relay RL1 is a high-reliability automotive-grade relay.

[0031] Through the setting of the first resistor R1, the second resistor R2, the first transistor Q1, and the relay RL1, it is possible to determine whether to stop the microwave according to whether the output of the first serial port IO1 of the microcontroller is a low level. In addition, the selection of highly reliable automotive-grade relays is conducive to improving the reliability of vehicle-mounted microwave oven products.

[0032] The microwave driving circuit 1 further includes a freewheeling diode D1, which is arranged in parallel at both ends of the coil of the relay RL1. The positive electrode of the freewheeling diode D1 is connected to the DC current output end of the coil of the relay RL1, and the negative electrode of the freewheeling diode D1 is connected to the DC current input end of the coil of the relay RL1.

[0033] By setting the freewheeling diode D1, it can be used to protect the relay RL1 coil and eliminate the reverse electromotive force, that is, the reverse voltage, to avoid the problem of the coil being damaged by the reverse electromotive force, thereby improving the safety of the circuit in the microwave driving circuit 1.

[0034] The isolation circuit 3 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, and an optical coupler U1. The second serial port IO2 is connected to the base of the second transistor Q2 through the third resistor R3, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the pin 2 of the optical coupler U1; the pin 1 of the optical coupler U1 is connected to the second power supply VCC through the fourth resistor R4, and the voltage value of the second power supply VCC is set as required; the pin 3 of the optical coupler U1 is connected to the control electrode of the thyristor T1, and the pin 4 of the optical coupler U1 is connected to the anode of the thyristor T1 through the fifth resistor R5. In this embodiment, the voltage value of the second power supply VCC is 5V.

[0035] By setting up the components in the isolation circuit 3, the electrical protection of the control circuit for the closing and opening of the relay RL1 in the microwave driving circuit 1 can be effectively improved, which is also beneficial to improving the accuracy of microwave starting and stopping, enhancing the stability of the control circuit before and after microwave starting, and avoiding the impact on the relay when the microwave is started and shut down, preventing the relay contacts from sticking, and at the same time avoiding the serious problem of thyristor heating due to long-term high current.

[0036] The protection circuit 2 includes a capacitor C1, a sixth resistor R6, and a varistor VR1. The current input end of the sixth resistor R6 is respectively connected to the anode of the thyristor T1, the current input end of the varistor VR1, and the live wire AC-L of the AC power supply. The current output end of the sixth resistor R6 is respectively electrically connected to the cathode of the thyristor T1, the current output end of the varistor VR1, and the current input end of the transformer L through the capacitor C1.

[0037] The capacitor C1, the sixth resistor R6 and the varistor VR1 are provided to protect the thyristor T1, thereby preventing excessive microwave starting current from damaging the thyristor T1, thereby effectively improving the protection of the thyristor T1 and enhancing the safety and reliability of the control circuit.

[0038] The specific working principle is:

[0039] a. Start the microwave:

[0040] The second serial port IO2 of the single-chip computer is set to output high level, Q2 is turned on, the optocoupler U1 is turned on, the thyristor T1 is controlled to be turned on for 2 seconds, the transformer L is energized, and the microwave is started. During the thyristor conduction time, the first serial port IO1 is set to high level, Q1 is turned on, and the relay is energized;

[0041] b. Stop the microwave:

[0042] The IO1 port of the single-chip computer is set to output a low level, Q1 is cut off, the relay RL1 is disconnected, the thyristor T1 is disconnected in 2 seconds, the transformer L is powered off, and the microwave stops.

[0043] When starting the microwave, the single chip microcomputer controls the thyristor T1 to open first, then controls the relay RL1 to open, and then closes the thyristor T1. When stopping the microwave, the thyristor T1 is opened first, then the relay RL1 is closed, and then the thyristor T1 is controlled to close. This can avoid the impact on the relay RL1 when the microwave is started and closed, prevent the contacts of the relay RL1 from sticking, and at the same time help to avoid the serious heating problem caused by the thyristor T1 passing a large current for a long time.

[0044] A vehicle-mounted microwave oven, the microwave oven applying the microwave control circuit, the microwave control circuit being arranged inside the vehicle-mounted microwave oven.

[0045] In the utility model, any vehicle-mounted microwave oven control circuit may include a microwave control circuit and a vehicle-mounted microwave oven structure as described in this embodiment, and based on the related structures and assembly relationships of the single-chip microcomputer, optocoupler, and thyristor provided in this embodiment, the vehicle-mounted microwave oven control circuit also includes conventional components including a cooking cavity, electrical wires, a magnetron, and other structures; in view of the fact that they are all prior art, they will not be described in detail here.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microwave control circuit, characterized in that: The device comprises a microwave driving circuit (1), a thyristor T1, a protection circuit (2), and an isolation circuit (3). The microwave driving circuit (1) and the isolation circuit (3) are connected to a transformer L via the thyristor T1 and the protection circuit (2) in sequence. The ends of the microwave driving circuit (1) and the isolation circuit (3) away from the thyristor T1 are connected to a single chip microcomputer.

2. A microwave control circuit according to claim 1, characterized in that: The single chip microcomputer comprises a first serial port IO1 and a second serial port IO2, the first serial port IO1 is connected to the microwave driving circuit (1), and the second serial port IO2 is connected to the isolation circuit (3).

3. A microwave control circuit according to claim 2, characterized in that: The microwave driving circuit (1) comprises a first resistor R1, a second resistor R2, a first transistor Q1, and a relay RL1. The first resistor R1, the first transistor Q1, the second resistor R2, the relay RL1, and the thyristor T1 are connected in sequence, and one end of the first resistor R1 away from the first transistor Q1 is connected to the single chip computer.

4. A microwave control circuit according to claim 3, characterized in that: The first serial port IO1 is electrically connected to the base of the first transistor Q1 through the first resistor R1; the collector of the first transistor Q1 is connected to the first power supply VDD through the second resistor R2 and the coil of the relay RL1 in sequence; the emitter of the first transistor Q1 is grounded; one end of the contact switch of the relay RL1 is respectively connected to the live wire AC-L of the AC power supply, the anode of the thyristor T1, the isolation circuit (3), and the protection circuit (2); the other end of the contact switch of the relay RL1 is respectively connected to the cathode of the thyristor T1, the protection circuit (2), and the current input end of the transformer L; the current output end of the transformer L is connected to the neutral wire AC-N of the AC power supply.

5. A microwave control circuit according to claim 3, characterized in that: The microwave driving circuit (1) further comprises a freewheeling diode D1, which is arranged in parallel at both ends of the coil of the relay RL1.

6. A microwave control circuit according to claim 5, characterized in that: The anode of the freewheeling diode D1 is connected to the DC current output end of the coil of the relay RL1 , and the cathode of the freewheeling diode D1 is connected to the DC current input end of the coil of the relay RL1 .

7. A microwave control circuit according to claim 2, characterized in that: The isolation circuit (3) comprises a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, and an optical coupler U1; the second serial port IO2 is connected to the base of the second transistor Q2 via the third resistor R3, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the pin 2 of the optical coupler U1; the pin 1 of the optical coupler U1 is connected to the second power supply VCC via the fourth resistor R4, the pin 3 of the optical coupler U1 is connected to the control electrode of the thyristor T1, and the pin 4 of the optical coupler U1 is connected to the anode of the thyristor T1 via the fifth resistor R5.

8. A microwave control circuit according to claim 2, characterized in that: The protection circuit (2) comprises a capacitor C1, a sixth resistor R6, and a varistor VR1; a current input end of the sixth resistor R6 is respectively connected to an anode of the thyristor T1, a current input end of the varistor VR1, and a live wire AC-L of an alternating current power supply; a current output end of the sixth resistor R6 is respectively electrically connected to a cathode of the thyristor T1, a current output end of the varistor VR1, and a current input end of a transformer L through the capacitor C1.

9. A microwave control circuit according to claim 2, characterized in that: At least one single chip microcomputer is provided.

10. A vehicle-mounted microwave oven, characterized in that: The microwave oven applies a microwave control circuit as described in any one of claims 1 to 9, and the microwave control circuit is arranged inside the vehicle-mounted microwave oven.

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