CN216751545U

CN216751545U - Reverse energy feedback self-adaptive microwave power supply

Info

Publication number: CN216751545U
Application number: CN202123435178.3U
Authority: CN
Inventors: 江阔善; 李云孝; 刘乾文; 黄绍秋; 曾楚钰
Original assignee: Xiamen High Power Electronics Co ltd
Current assignee: Xiamen High Power Electronics Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-06-14
Anticipated expiration: 2031-12-31

Abstract

The utility model discloses a reverse energy feedback self-adaptive microwave power supply which comprises an input rectifying circuit, a high-voltage transformer T1, a PWM (pulse-width modulation) switching circuit, an output rectifying circuit, an MCU (microprogrammed control unit) processor U1 and a sampling circuit, wherein the input rectifying circuit is connected with the input rectifying circuit; the input rectifying circuit is connected with a first end of a primary winding of a high-voltage transformer T1, the input end of the PWM switching circuit is connected with a second end of the primary winding of a high-voltage transformer T1, and the output end of the PWM switching circuit is grounded; the output rectifying circuit is connected with a first secondary winding and a second secondary winding of the high-voltage transformer T1; one output port of the MCU processor U1 is connected with the control end of the PWM switching circuit; and an AD sampling port of the MCU processor U1 is connected with the second end of the primary winding of the high-voltage transformer T1 through a sampling circuit. The utility model avoids the complex installation in the prior art and can quickly and effectively protect the magnetron.

Description

Reverse energy feedback self-adaptive microwave power supply

Technical Field

The utility model relates to the field of microwave heating, in particular to a reverse energy feedback self-adaptive microwave power supply.

Background

In household microwave ovens and industrial microwave heating equipment, heating is carried out by utilizing the principle of microwave heating, namely electric energy → microwave → heat energy, wherein the most main components comprise a microwave power supply, a magnetron and a heating cavity, the microwave power supply is a variable frequency power supply which converts commercial power into a variable frequency power supply capable of driving the magnetron, the magnetron is a key component which converts electric energy into microwave, and the heating cavity is an electromagnetic closed space for placing a heated body and receiving microwave; under the drive of a microwave power supply, the magnetron converts electric energy into microwaves to be emitted into the heating cavity, and a heated body placed in the heating cavity absorbs the microwaves and converts the microwaves into heat energy; if the heating cavity is not heated or the heated body is exhausted, the microwave emitted by the magnetron is not absorbed and can be reflected in the heating cavity, so that redundant microwave can be reflected to the magnetron, the microwave reflected to the magnetron is called feedback energy, and the feedback energy can be converted into heat energy to cause the temperature rise of the magnetron and even cause the damage of the magnetron.

In the prior art, the conventional microwave power supply cannot detect the magnitude of the feedback energy and the temperature of the magnetron, so that only an over-temperature protection switch or a temperature sensor can be passively installed on the magnetron, but the installation of the over-temperature protection switch or the temperature sensor on the magnetron is complicated, the over-temperature protection switch or the temperature sensor is not timely in response, and the magnetron may be damaged when the temperature of the magnetron rises to a certain value.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a reverse energy feedback self-adaptive microwave power supply to overcome the defects of the prior art.

In order to achieve the above purpose, the solution of the utility model is:

a reverse energy feedback self-adaptive microwave power supply comprises an input rectifying circuit, a high-voltage transformer T1, a PWM (pulse-width modulation) switching circuit, an output rectifying circuit, an MCU (microprogrammed control unit) processor U1 and a sampling circuit; the input rectifying circuit is connected with a first end of a primary winding of a high-voltage transformer T1, the input end of the PWM switching circuit is connected with a second end of the primary winding of a high-voltage transformer T1, and the output end of the PWM switching circuit is grounded; the output rectifying circuit is connected with a first secondary winding and a second secondary winding of the high-voltage transformer T1; one output port of the MCU processor U1 is connected with the control end of the PWM switching circuit; and an AD sampling port of the MCU processor U1 is connected with the second end of the primary winding of the high-voltage transformer T1 through a sampling circuit.

The sampling circuit comprises a resistor R7 and a resistor R8; the first end of the resistor R7 is connected with the second end of the primary winding of the high-voltage transformer T1, the second end of the resistor R7 is connected with the first end of the resistor R8 and serves as the output end of the sampling circuit, the output end of the sampling circuit is connected with the AD sampling port of the MCU processor U1, and the second end of the resistor R8 is grounded.

The first end of the resistor R7 is connected to the second end of the primary winding of the high voltage transformer T1 through a resistor R6.

The PWM switching circuit comprises a power switching tube Q1 and a power switching tube driving circuit; the input end of the power switch tube Q1 is used as the input end of the PWM switch circuit to connect the second end of the primary winding of the high voltage transformer T1, the output end of the power switch tube Q1 is used as the output end of the PWM switch circuit to be grounded, and the control end of the power switch tube Q1 is connected to the output port of the MCU processor U1 through the power switch tube driving circuit.

The PWM switching circuit further comprises a voltage dependent resistor VSR1, and two ends of the voltage dependent resistor VSR1 are respectively connected with the input end and the output end of the power switching tube Q1.

The power switch tube driving circuit comprises a resistor R2, a resistor R3, a resistor R4, a resistor R5, a triode Q2 and a triode Q3; the first end of the resistor R3 and the collector of the transistor Q2 are connected with a driving power supply VCC, the second end of the resistor R3 is connected with the first end of the resistor R2, the base of the transistor Q2 and the base of the transistor Q3 and serves as the control end of the PWM switching circuit to be connected with the output port of the MCU processor U1, the emitter of the transistor Q2 is connected with the emitter of the transistor Q3 and the first end of the resistor R4, the second end of the resistor R4 and the first end of the resistor R5 are connected with the control end of the power switching tube Q1, and the second end of the resistor R2, the second end of the resistor R5 and the collector of the transistor Q3 are grounded.

The power switch tube Q1 is an insulated gate bipolar transistor.

The output rectifying circuit comprises a diode D1, a diode D2, a diode D3, a diode D4, an inductor L2, a resistor R69, a capacitor C4, a capacitor C5 and a capacitor C6; the anode of the diode D1 and the first end of the inductor L2 are respectively connected with the first end and the second end of the second secondary winding of the high-voltage transformer T1, the second end of the inductor L2 is connected with the anode of the diode D2, the cathode of the diode D1 is connected with the cathode of the diode D2 and the first end of the capacitor C4 and serves as the first output end of the output rectifying circuit, the second end of the capacitor C4 is connected with the first end of the resistor R69 and the first end of the capacitor C5, the anode of the diode D3 and the center tap of the second secondary winding of the high-voltage transformer T1 are used as the second output end of the output rectifying circuit, the second end of the capacitor C5 is connected to the first end of the capacitor C6 and the first end of the first secondary winding of the high-voltage transformer T1, the cathode of the diode D3 is connected to the anode of the diode D4 and the second end of the first secondary winding of the high-voltage transformer T1, and the cathode of the diode D4 is connected to the second end of the capacitor C6 and the second end of the resistor R69 and is used as the third output end of the output rectifying circuit.

The input rectifying circuit is connected with the first end of the primary winding of the high-voltage transformer T1 through the input filter circuit.

The input filter circuit comprises an inductor L1 and a capacitor C2; the first end of the inductor L1 is connected with the output end of the input rectification circuit, the second end of the inductor L1 is connected with the first end of the capacitor C2 and the first end of the primary winding of the high-voltage transformer T1, and the second end of the capacitor C2 is grounded.

After the scheme is adopted, when the reverse energy feedback self-adaptive microwave power supply is used, the output rectifying circuit is connected with the three ends of the magnetron; when the reverse energy feedback self-adaptive microwave power supply works, the MCU processor U1 outputs a PWM signal to the PWM switching circuit to control the on-off frequency of the PWM switching circuit, so that the primary winding of the high-voltage transformer T1 generates an alternating current signal, and the high-voltage transformer T1 transmits primary energy to a secondary winding to enable the output rectifying circuit to drive the magnetron to work; meanwhile, the MCU processor U1 acquires the voltage of the second end of the primary winding of the high voltage transformer T1 in real time through the sampling circuit, the voltage value of the second end of the primary winding of the high voltage transformer T1 can feed back the feedback energy received by the magnetron, so that the MCU processor U1 can obtain the feedback energy information received by the magnetron in real time, and the MCU processor U1 adjusts the PWM signal accordingly according to the feedback energy information received by the magnetron, so as to adjust the output power of the feedback energy adaptive microwave power supply of the present invention accordingly.

Therefore, the MCU processor U1 of the utility model can acquire the voltage of the second end of the primary winding of the high-voltage transformer T1 in real time through the sampling circuit to acquire the feedback energy information received by the magnetron in real time, so that an over-temperature protection switch or a temperature sensor is not required to be additionally installed to avoid the complex installation of devices, and meanwhile, the MCU processor U1 can acquire the feedback energy information received by the magnetron in real time to quickly control the magnetron to avoid the damage of the magnetron.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

In order to further explain the technical solution of the present invention, the present invention is explained in detail by the following specific examples.

As shown in fig. 1, the present invention discloses a reverse feedback energy adaptive microwave power supply, which includes an input rectification circuit, a high voltage transformer T1, a PWM switching circuit, an output rectification circuit, an MCU processor U1, and a sampling circuit; the input rectification circuit is connected with a first end of a primary winding of a high-voltage transformer T1, an input end of the PWM switching circuit is connected with a second end of the primary winding of the high-voltage transformer T1, and an output end of the PWM switching circuit is grounded; the output rectifying circuit is connected with a first secondary winding and a second secondary winding of the high-voltage transformer T1; one output port of the MCU processor U1 is connected with the control end of the PWM switching circuit; and an AD sampling port of the MCU processor U1 is connected with the second end of the primary winding of the high-voltage transformer T1 through a sampling circuit.

When the reverse energy feedback self-adaptive microwave power supply is used, the output rectifying circuit is connected with the three ends of the magnetron; when the reverse energy feedback self-adaptive microwave power supply works, the MCU processor U1 outputs a PWM signal to the PWM switching circuit to control the on-off frequency of the PWM switching circuit, so that the primary winding of the high-voltage transformer T1 generates an alternating current signal, and the high-voltage transformer T1 transmits primary energy to a secondary winding to enable the output rectifying circuit to drive the magnetron to work; meanwhile, the MCU processor U1 acquires the voltage of the second end of the primary winding of the high voltage transformer T1 in real time through the sampling circuit, the voltage value of the second end of the primary winding of the high voltage transformer T1 can feed back the feedback energy received by the magnetron, so that the MCU processor U1 can obtain the feedback energy information received by the magnetron in real time, and the MCU processor U1 adjusts the PWM signal accordingly according to the feedback energy information received by the magnetron, so as to adjust the output power of the feedback energy adaptive microwave power supply of the present invention accordingly.

In the present invention, the method for acquiring the feedback energy information received by the magnetron by the MCU processor U1 may be: the MCU processor U1 respectively collects V1, V2 and V3. cna 1. cna. Vn voltage values of the second end of the primary winding of the high-voltage transformer T1 at the time of T1, T2, T3. cna 1. cna, and tn, calculates the average value Van 1 of the average values V1, V2 and V3. cna. 1 and the average value Van of the average value Vn 1. cna. Vn in real time, compares the difference value of the two values Van and Va1, and judges the magnitude of reverse feedback energy received by the magnetron according to the magnitude of the difference value of the Van and the Va 1; when the feedback energy exceeds a preset threshold value, the MCU processor U1 reduces the power output of the microwave power supply according to an algorithm, so that the microwave output of the magnetron is reduced, and the feedback energy is further reduced.

In the present invention, the sampling circuit is a resistance sampling circuit, and specifically, the sampling circuit includes a resistance R7 and a resistance R8; the first end of the resistor R7 is connected with the second end of the primary winding of the high-voltage transformer T1, the second end of the resistor R7 is connected with the first end of the resistor R8 and serves as the output end of the sampling circuit, the output end of the sampling circuit is connected with the AD sampling port of the MCU processor U1, and the second end of the resistor R8 is grounded. The first end of the resistor R7 can be connected with the second end of the primary winding of the high-voltage transformer T1 through a resistor R6, and the resistor R6 can play a role in limiting current to protect the MCU processor U1.

In the utility model, the PWM switching circuit comprises a power switching tube Q1 and a power switching tube driving circuit; the power switch tube Q1 can be an insulated gate bipolar transistor; the input end of the power switch tube Q1 is used as the input end of the PWM switch circuit to connect the second end of the primary winding of the high voltage transformer T1, the output end of the power switch tube Q1 is used as the output end of the PWM switch circuit to be grounded, and the control end of the power switch tube Q1 is connected to the output port of the MCU processor U1 through the power switch tube driving circuit. The PWM switching circuit can further comprise a voltage dependent resistor VSR1, two ends of a voltage dependent resistor VSR1 are respectively connected with the input end and the output end of the power switching tube Q1, and the voltage dependent resistor VSR1 can play a protection role on the power switching tube Q1 so as to prevent the power switching tube Q1 from being damaged due to overvoltage. The input terminal of the power switch Q1 may be connected to the first terminal of the primary winding of the high voltage transformer T1 through a capacitor C3.

In the utility model, the power switch tube driving circuit comprises a resistor R2, a resistor R3, a resistor R4, a resistor R5, a triode Q2 and a triode Q3; the first end of the resistor R3 and the collector of the transistor Q2 are connected with a driving power supply VCC, the second end of the resistor R3 is connected with the first end of the resistor R2, the base of the transistor Q2 and the base of the transistor Q3 and serves as the control end of the PWM switching circuit to be connected with the output port of the MCU processor U1, the emitter of the transistor Q2 is connected with the emitter of the transistor Q3 and the first end of the resistor R4, the second end of the resistor R4 and the first end of the resistor R5 are connected with the control end of the power switching tube Q1, and the second end of the resistor R2, the second end of the resistor R5 and the collector of the transistor Q3 are grounded.

In the utility model, the output rectifying circuit comprises a diode D1, a diode D2, a diode D3, a diode D4, an inductor L2, a resistor R69, a capacitor C4, a capacitor C5 and a capacitor C6; wherein the anode of the diode D1 and the first end of the inductor L2 are respectively connected with the first end and the second end of the second secondary winding of the high-voltage transformer T1, the second end of the inductor L2 is connected with the anode of the diode D2, the cathode of the diode D1 is connected with the cathode of the diode D2 and the first end of the capacitor C4 and serves as the first output end of the output rectifying circuit, the second end of the capacitor C4 is connected with the first end of the resistor R69 and the first end of the capacitor C5, the anode of the diode D3 and the center tap of the second secondary winding of the high-voltage transformer T1 are used as the second output end of the output rectification circuit, the second end of the capacitor C5 is connected to the first end of the capacitor C6 and the first end of the first secondary winding of the high-voltage transformer T1, the cathode of the diode D3 is connected to the anode of the diode D4 and the second end of the first secondary winding of the high-voltage transformer T1, and the cathode of the diode D4 is connected to the second end of the capacitor C6 and the second end of the resistor R69 and is used as the third output end of the output rectification circuit. The first output end, the second output end and the third output end of the output rectifying circuit are used for being connected with a first filament wire pin, a second filament wire pin and an anode pin of a magnetron respectively.

In the utility model, the input rectifying circuit is connected with the first end of the primary winding of the high-voltage transformer T1 through the input filter circuit. The input filter circuit has a filtering function, so that the feedback energy self-adaptive microwave power supply can work more stably; the input filter circuit may include an inductance L1 and a capacitance C2; the first end of the inductor L1 is connected with the output end of the input rectification circuit, the second end of the inductor L1 is connected with the first end of the capacitor C2 and the first end of the primary winding of the high-voltage transformer T1, and the second end of the capacitor C2 is grounded. The input rectifying circuit is used for converting alternating current into direct current, and a rectifying bridge stack can be adopted.

The above embodiments and drawings are not intended to limit the form and style of the product of the present invention, and any suitable changes or modifications thereof by one of ordinary skill in the art should be considered as not departing from the scope of the present invention.

Claims

1. A feedback energy self-adaptive microwave power supply is characterized in that: the device comprises an input rectifying circuit, a high-voltage transformer T1, a PWM switching circuit, an output rectifying circuit, an MCU processor U1 and a sampling circuit;

the input rectifying circuit is connected with a first end of a primary winding of a high-voltage transformer T1, the input end of the PWM switching circuit is connected with a second end of the primary winding of a high-voltage transformer T1, and the output end of the PWM switching circuit is grounded;

the output rectifying circuit is connected with a first secondary winding and a second secondary winding of the high-voltage transformer T1;

one output port of the MCU processor U1 is connected with the control end of the PWM switching circuit; and an AD sampling port of the MCU processor U1 is connected with the second end of the primary winding of the high-voltage transformer T1 through a sampling circuit.

2. A reverse energy feed adaptive microwave power supply as claimed in claim 1 wherein: the sampling circuit comprises a resistor R7 and a resistor R8; the first end of the resistor R7 is connected with the second end of the primary winding of the high-voltage transformer T1, the second end of the resistor R7 is connected with the first end of the resistor R8 and serves as the output end of the sampling circuit, the output end of the sampling circuit is connected with the AD sampling port of the MCU processor U1, and the second end of the resistor R8 is grounded.

3. A reverse energy feed adaptive microwave power supply as claimed in claim 2 wherein: the first end of the resistor R7 is connected to the second end of the primary winding of the high voltage transformer T1 through a resistor R6.

4. A reverse energy feed adaptive microwave power supply as claimed in claim 1 wherein: the PWM switching circuit comprises a power switching tube Q1 and a power switching tube driving circuit; the input end of the power switch tube Q1 is used as the input end of the PWM switch circuit to connect the second end of the primary winding of the high voltage transformer T1, the output end of the power switch tube Q1 is used as the output end of the PWM switch circuit to be grounded, and the control end of the power switch tube Q1 is connected to the output port of the MCU processor U1 through the power switch tube driving circuit.

5. A reverse energy feed adaptive microwave power supply as claimed in claim 4 wherein: the PWM switching circuit further comprises a voltage dependent resistor VSR1, and two ends of the voltage dependent resistor VSR1 are respectively connected with the input end and the output end of the power switching tube Q1.

6. A self-adapting reverse-fed microwave power supply as in claim 4 wherein: the power switch tube driving circuit comprises a resistor R2, a resistor R3, a resistor R4, a resistor R5, a triode Q2 and a triode Q3;

the first end of the resistor R3 and the collector of the transistor Q2 are connected with a driving power supply VCC, the second end of the resistor R3 is connected with the first end of the resistor R2, the base of the transistor Q2 and the base of the transistor Q3 and serves as the control end of the PWM switching circuit to be connected with the output port of the MCU processor U1, the emitter of the transistor Q2 is connected with the emitter of the transistor Q3 and the first end of the resistor R4, the second end of the resistor R4 and the first end of the resistor R5 are connected with the control end of the power switching tube Q1, and the second end of the resistor R2, the second end of the resistor R5 and the collector of the transistor Q3 are grounded.

7. A self-adapting reverse-fed microwave power supply as in claim 4 wherein: the power switch tube Q1 is an insulated gate bipolar transistor.

8. A reverse energy feed adaptive microwave power supply as claimed in claim 1 wherein: the output rectifying circuit comprises a diode D1, a diode D2, a diode D3, a diode D4, an inductor L2, a resistor R69, a capacitor C4, a capacitor C5 and a capacitor C6;

the anode of the diode D1 and the first end of the inductor L2 are respectively connected with the first end and the second end of the second secondary winding of the high-voltage transformer T1, the second end of the inductor L2 is connected with the anode of the diode D2, the cathode of the diode D1 is connected with the cathode of the diode D2 and the first end of the capacitor C4 and serves as the first output end of the output rectifying circuit, the second end of the capacitor C4 is connected with the first end of the resistor R69 and the first end of the capacitor C5, the anode of the diode D3 and the center tap of the second secondary winding of the high-voltage transformer T1 are used as the second output end of the output rectifying circuit, the second end of the capacitor C5 is connected to the first end of the capacitor C6 and the first end of the first secondary winding of the high-voltage transformer T1, the cathode of the diode D3 is connected to the anode of the diode D4 and the second end of the first secondary winding of the high-voltage transformer T1, and the cathode of the diode D4 is connected to the second end of the capacitor C6 and the second end of the resistor R69 and is used as the third output end of the output rectifying circuit.

9. A reverse energy feed adaptive microwave power supply as claimed in claim 1 wherein: the input rectifying circuit is connected with the first end of the primary winding of the high-voltage transformer T1 through the input filter circuit.

10. A feedback energy adaptive microwave power supply as claimed in claim 9 wherein: the input filter circuit comprises an inductor L1 and a capacitor C2; the first end of the inductor L1 is connected with the output end of the input rectification circuit, the second end of the inductor L1 is connected with the first end of the capacitor C2 and the first end of the primary winding of the high-voltage transformer T1, and the second end of the capacitor C2 is grounded.