Electronic transformer for microwave oven

Abstract

The utility model relates to an electronic transformer for a microwave oven. The electronic transformer comprises a first rectifying and filtering unit and a power conversion unit connected with the first rectifying and filtering unit, the transformer is connected with the power conversion unit; the second rectifying and filtering unit is connected with the transformer and is used for outputting direct-current high-voltage electricity; the microwave oven magnetron is connected with the second rectifying and filtering unit; the control unit is connected with the power conversion unit; the power adjusting unit is connected with the control unit and used for adjusting the output power of the electronic transformer; and a timer for controlling the output power of the electronic transformer according to preset operation time is arranged in the control unit. The electronic transformer for the microwave oven provided by the utility model is provided with the power adjusting unit, so that the input power can be automatically reduced when the temperature of the anode of the magnetron of the microwave oven is too high, and the magnetron of the microwave oven can be further effectively protected; in addition, a timer is arranged in the control unit, so that the input power can be reduced according to the working duration without arranging an external communication connecting line.

Description

Technical Field

[0001] This utility model belongs to the field of microwave oven power supply technology, specifically relating to an electronic transformer for microwave ovens. Background Technology

[0002] A traditional microwave oven consists of a cavity, control system, cooling system, lighting system, magnetron, and magnetron drive power supply, among which the magnetron drive power supply is a traditional power frequency leakage transformer. With technological advancements and increased awareness of energy conservation, a new type of switching power supply, commonly known as an electronic transformer, has become widely used, directly replacing the traditional power frequency leakage transformer. Microwave ovens using electronic transformers offer advantages such as energy saving, lighter weight, better cooking results, and quieter operation.

[0003] However, when existing electronic transformers replace traditional power frequency leakage transformers, the following problems exist: 1. Existing electronic transformers lack external communication connections, thus making it impossible to reduce power according to operating time via external control commands. 2. After a power outage, existing electronic transformers will operate at their initial maximum power upon restarting, resulting in a higher input power than leakage transformers. At this time, the magnetron itself is still hot and cannot withstand the increased power, easily leading to overheating and damage.

[0004] Therefore, this utility model provides an electronic transformer for microwave ovens to solve the above-mentioned technical problems. Utility Model Content

[0005] To address the aforementioned problems, the purpose of this invention is to provide an electronic transformer for microwave ovens, which is equipped with a power adjustment unit that can automatically reduce the input power when the anode temperature of the microwave oven magnetron is too high, thereby effectively protecting the microwave oven magnetron.

[0006] This utility model provides an electronic transformer for a microwave oven, comprising:

[0007] The first rectifier and filter unit is used to convert the input AC voltage into DC voltage;

[0008] A power conversion unit connected to the first rectifier and filter unit for converting the DC voltage into an AC pulse voltage;

[0009] A transformer connected to the power conversion unit for voltage conversion of the AC pulse voltage;

[0010] A second rectifier and filter unit connected to the transformer is used to rectify and filter the voltage after it has been transformed by the transformer, so as to output DC high voltage.

[0011] A microwave oven magnetron connected to the second rectifier and filter unit to receive the DC high voltage and operate;

[0012] A control unit connected to the power conversion unit for driving the power conversion unit to convert the DC voltage into the AC pulse voltage;

[0013] A power adjustment unit connected to the control unit for adjusting the output power of the electronic transformer according to predetermined conditions;

[0014] The control unit is equipped with a timer for controlling the output power of the electronic transformer according to a predetermined running time.

[0015] Preferably, the power adjustment unit includes an anode voltage sampling unit and a temperature detection unit connected to the control unit. The anode sampling unit is used to reduce the input power when the anode temperature of the microwave oven magnetron is too high, and the temperature detection unit is used to reduce the input power when the temperature of any one of the power devices in the first rectification and filtering unit, the power conversion unit, the transformer, and the second rectification and filtering unit is too high.

[0016] Preferably, the anode voltage sampling unit includes a first circuit connected to the anode and cathode of the induction cooker magnetron, a filament winding connected to the first circuit for providing filament voltage to the induction cooker magnetron, and a second circuit connected in parallel with the filament winding and connected to the control unit.

[0017] Preferably, the first circuit includes a high-voltage winding disposed on the high-voltage side of the transformer and a first voltage doubler rectifier circuit connected to the high-voltage winding. A first terminal of the first voltage doubler rectifier circuit is connected to the high-voltage winding, and a second terminal of the first voltage doubler rectifier circuit is connected to the anode and cathode of the induction cooker magnetron. The first voltage doubler rectifier circuit includes a first diode assembly connected to the high-voltage winding, a first capacitor assembly disposed in parallel with the first diode assembly, and a resistor disposed in parallel with the first capacitor assembly. A first output terminal of the resistor is connected to the anode of the induction cooker magnetron, and a second output terminal of the resistor is connected to the cathode of the induction cooker magnetron.

[0018] The filament winding is located on the high-voltage side of the transformer and is simultaneously connected to the first diode assembly and the first capacitor assembly.

[0019] The second circuit includes an anode voltage sampling winding on the high-voltage side of the transformer and a second voltage doubler rectifier circuit connected to the anode voltage sampling winding. The first terminal of the second voltage doubler rectifier circuit is connected to the anode voltage sampling winding, and the second terminal of the second voltage doubler rectifier circuit is connected to the control unit. The second voltage doubler rectifier circuit includes a second diode assembly connected to the anode voltage sampling winding, a second capacitor assembly connected to the anode voltage sampling winding and connected in parallel with the second diode assembly, and an inductor connected to both the second diode assembly and the second capacitor assembly. The first terminal of the inductor is connected to both the second diode assembly and the second capacitor assembly, and the second terminal of the inductor is connected to the control unit.

[0020] Preferably, the first diode assembly includes a first diode and a second diode connected in series; the first capacitor assembly includes a first capacitor and a second capacitor connected in series; the first end of the high-voltage winding is connected to the positive terminal of the first capacitor, the second capacitor, and the first diode simultaneously; the second end of the high-voltage winding is connected to the negative terminal of the second diode simultaneously; and the filament winding is connected to the positive terminal of the second diode and the first capacitor simultaneously.

[0021] The second diode assembly includes a third diode and a fourth diode connected in series; the second capacitor assembly includes a third capacitor and a fourth capacitor connected in series; the first end of the anode voltage sampling winding is connected to both the positive terminal of the third diode and the negative terminal of the fourth diode, and the second end of the anode voltage sampling winding is connected to both the third capacitor and the fourth capacitor; the first end of the inductor is connected to both the negative terminal of the third diode, the positive terminal of the fourth diode, and the fourth capacitor.

[0022] Compared with related technologies, this utility model provides an electronic transformer for a microwave oven, which includes a first rectifier and filter unit for converting an input AC voltage into a DC voltage; a power conversion unit connected to the first rectifier and filter unit for converting the DC voltage into an AC pulse voltage; a transformer connected to the power conversion unit for voltage conversion of the AC pulse voltage; a second rectifier and filter unit connected to the transformer for rectifying and filtering the voltage converted by the transformer to output high-voltage DC electricity; a microwave oven magnetron connected to the second rectifier and filter unit for receiving the high-voltage DC electricity and operating thereon; a control unit connected to the power conversion unit for driving the power conversion unit to convert the DC voltage into the AC pulse voltage; and a power adjustment unit connected to the control unit for adjusting the output power of the electronic transformer according to predetermined conditions; the control unit includes a timer for controlling the output power of the electronic transformer according to a predetermined running time. In the above structure, the power adjustment unit can automatically reduce the input power when the anode temperature of the microwave oven magnetron is too high or when the temperature of any power device in the rectifier filter unit, power conversion unit, transformer, and high-voltage rectifier filter unit is too high, thereby effectively protecting the microwave oven magnetron and power devices. In addition, the control unit is equipped with a timer, which can reduce the input power according to the working time without the need for an external communication connection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the circuit structure of an electronic transformer for a microwave oven according to the present invention.

[0024] Figure 2 This is a schematic diagram of the circuit structure of the anode voltage sampling unit of this utility model.

[0025] Reference numerals: First rectifier and filter unit-1; Power conversion unit-2; Transformer-3; Second rectifier and filter unit-4; Microwave oven magnetron-5; Control unit-6; Power adjustment unit-7; First circuit-10; Second circuit-20. Detailed Implementation

[0026] This invention provides an electronic transformer for microwave ovens, aiming to solve the problems of traditional electronic transformers lacking external communication lines, thus making it impossible to reduce power according to working time through external control commands and causing the magnetron to easily overheat and be damaged.

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0028] Please also refer to the appendix. Figure 1-2 This utility model provides an electronic transformer for a microwave oven, comprising:

[0029] First rectifier and filter unit 1 is used to convert the input AC voltage into DC voltage;

[0030] A power conversion unit 2 is connected to the first rectifier and filter unit 1 to convert the DC voltage into an AC pulse voltage;

[0031] A transformer 3 is connected to the power conversion unit 2 for voltage conversion of the AC pulse voltage;

[0032] A second rectifier and filter unit 4 is connected to the transformer 3 to rectify and filter the voltage after it has been transformed by the transformer 3, so as to output DC high voltage.

[0033] The microwave oven magnetron 5 is connected to the second rectifier and filter unit 4 to receive the DC high voltage and perform its operation;

[0034] A control unit 6 connected to the power conversion unit 2 for driving the power conversion unit 2 to convert the DC voltage into the AC pulse voltage;

[0035] A power adjustment unit 7 is connected to the control unit 6 for adjusting the output power of the electronic transformer according to predetermined conditions;

[0036] The control unit 7 is equipped with a timer for controlling the output power of the electronic transformer according to a predetermined running time.

[0037] In the above structure, the power adjustment unit 7 can automatically reduce the input power when the anode temperature of the microwave oven magnetron 5 is too high or when the temperature of any power device in the first rectifier filter unit 1, power conversion unit 2, transformer 3, and second rectifier filter unit 4 is too high, thereby effectively protecting the microwave oven magnetron and power devices. In addition, the control unit 6 is equipped with a timer, which can reduce the input power according to the working time without the need for an external communication connection.

[0038] In this embodiment, the power adjustment unit 7 includes an anode voltage sampling unit 71 and a temperature detection unit 72 connected to the control unit 6. The anode sampling unit 71 is used to reduce the input power when the anode temperature of the microwave oven magnetron 5 is too high. The temperature detection unit 72 is used to reduce the input power when the temperature of any one of the power devices in the first rectifier filter unit 1, the power conversion unit 2, the transformer 3, and the second rectifier filter unit 4 is too high.

[0039] Specifically, the anode voltage sampling unit 71 includes a first circuit 10 connected to the anode and cathode of the induction cooker magnetron 5, a filament winding W2 connected to the first circuit 10 for providing filament voltage to the induction cooker magnetron 5, and a second circuit 20 connected in parallel with the filament winding W2 and connected to the control unit 6.

[0040] Furthermore, the first circuit 10 includes a high-voltage winding W1 disposed on the high-voltage side of the transformer 3 and a first voltage doubler rectifier circuit 101 connected to the high-voltage winding. The first terminal of the first voltage doubler rectifier circuit 101 is connected to the high-voltage winding W1, and the second terminal of the first voltage doubler rectifier circuit 101 is connected to the anode and cathode of the induction cooker magnetron 5. The first voltage doubler rectifier circuit 101 includes a first diode assembly connected to the high-voltage winding W1, a first capacitor assembly disposed in parallel with the first diode assembly, and a resistor R1 disposed in parallel with the first capacitor assembly. The first output terminal of the resistor R1 is connected to the anode of the induction cooker magnetron 5, and the second output terminal of the resistor R1 is connected to the cathode of the induction cooker magnetron 5. The filament winding W2 is disposed on the high-voltage side of the transformer 3 and is simultaneously connected to the first diode assembly and the first capacitor assembly.

[0041] The second circuit 20 includes an anode voltage sampling winding W3 on the high-voltage side of the transformer 3 and a second voltage doubler rectifier circuit 201 connected to the anode voltage sampling winding W3. The first end of the second voltage doubler rectifier circuit 201 is connected to the anode voltage sampling winding W3, and the second end of the second voltage doubler rectifier circuit 201 is connected to the control unit 6. The second voltage doubler rectifier circuit 201 includes a second diode assembly connected to the anode voltage sampling winding W3, a second capacitor assembly connected to the anode voltage sampling winding W3 and connected in parallel with the second diode assembly, and an inductor L connected to both the second diode assembly and the second capacitor assembly. The first end of the inductor L is connected to both the second diode assembly and the second capacitor assembly, and the second end of the inductor L is connected to the control unit 6.

[0042] Furthermore, the first diode assembly includes a first diode D1 and a second diode D2 connected in series; the first capacitor assembly includes a first capacitor C1 and a second capacitor C2 connected in series; the first end of the high-voltage winding W1 is simultaneously connected to the first capacitor C1, the second capacitor C2, and the positive terminal of the first diode D1, and the second end of the high-voltage winding W1 is connected to the negative terminal of the second diode D2; the filament winding W2 is simultaneously connected to the positive terminal of the second diode D2 and the first capacitor C1; the second diode assembly includes a third diode D3 and a fourth diode D4 connected in series; the second capacitor assembly includes a third capacitor C3 and a fourth capacitor C4 connected in series; the first end of the anode voltage sampling winding W3 is simultaneously connected to the positive terminal of the third diode D3 and the negative terminal of the fourth diode D4, and the second end of the anode voltage sampling winding W3 is connected to the third capacitor C3 and the fourth capacitor C4; the first end of the inductor L is simultaneously connected to the negative terminal of the third diode D3, the positive terminal of the fourth diode D4, and the fourth capacitor C4.

[0043] In addition, it is worth mentioning that the chip model used in the electronic transformer for microwave ovens provided by this utility model is VT3788.

[0044] Compared with related technologies, this utility model provides an electronic transformer for a microwave oven, which includes a first rectifier and filter unit for converting an input AC voltage into a DC voltage; a power conversion unit connected to the first rectifier and filter unit for converting the DC voltage into an AC pulse voltage; a transformer connected to the power conversion unit for voltage conversion of the AC pulse voltage; a second rectifier and filter unit connected to the transformer for rectifying and filtering the voltage converted by the transformer to output high-voltage DC electricity; a microwave oven magnetron connected to the second rectifier and filter unit for receiving the high-voltage DC electricity and operating thereon; a control unit connected to the power conversion unit for driving the power conversion unit to convert the DC voltage into the AC pulse voltage; and a power adjustment unit connected to the control unit for adjusting the output power of the electronic transformer according to predetermined conditions; the control unit includes a timer for controlling the output power of the electronic transformer according to a predetermined running time. In the above structure, the power adjustment unit can automatically reduce the input power when the anode temperature of the microwave oven magnetron is too high or when the temperature of any power device in the rectifier filter unit, power conversion unit, transformer, and high-voltage rectifier filter unit is too high, thereby effectively protecting the microwave oven magnetron and power devices. In addition, the control unit is equipped with a timer, which can reduce the input power according to the working time without the need for an external communication connection.

[0045] It should be noted that the above-described embodiments should be understood as illustrative, not as limiting the scope of protection of this utility model, which is defined by the claims. For those skilled in the art, non-essential improvements and adjustments made to this utility model without departing from its essence and scope still fall within the scope of protection of this utility model.

Claims

1. An electronic transformer for a microwave oven, characterized in that, The electronic transformer includes: The first rectifier and filter unit is used to convert the input AC voltage into DC voltage; A power conversion unit connected to the first rectifier and filter unit for converting the DC voltage into an AC pulse voltage; A transformer connected to the power conversion unit for voltage conversion of the AC pulse voltage; A second rectifier and filter unit connected to the transformer is used to rectify and filter the voltage after it has been transformed by the transformer, so as to output DC high voltage. A microwave oven magnetron connected to the second rectifier and filter unit to receive the DC high voltage and operate; A control unit connected to the power conversion unit for driving the power conversion unit to convert the DC voltage into the AC pulse voltage; A power adjustment unit connected to the control unit for adjusting the output power of the electronic transformer according to predetermined conditions; The control unit is equipped with a timer for controlling the output power of the electronic transformer according to a predetermined running time.

2. An electronic transformer for a microwave oven according to claim 1, characterized in that, The power adjustment unit includes an anode voltage sampling unit and a temperature detection unit connected to the control unit. The anode sampling unit is used to reduce the input power when the anode temperature of the microwave oven magnetron is too high. The temperature detection unit is used to reduce the input power when the temperature of any one of the power devices in the first rectification and filtering unit, the power conversion unit, the transformer, and the second rectification and filtering unit is too high.

3. An electronic transformer for a microwave oven according to claim 2, characterized in that, The anode voltage sampling unit includes a first circuit connected to the anode and cathode of the microwave oven magnetron, a filament winding connected to the first circuit for providing filament voltage to the microwave oven magnetron, and a second circuit connected in parallel with the filament winding and connected to the control unit.

4. An electronic transformer for a microwave oven according to claim 3, characterized in that, The first circuit includes a high-voltage winding disposed on the high-voltage side of the transformer and a first voltage doubler rectifier circuit connected to the high-voltage winding. A first terminal of the first voltage doubler rectifier circuit is connected to the high-voltage winding, and a second terminal of the first voltage doubler rectifier circuit is connected to the anode and cathode of the microwave oven magnetron. The first voltage doubler rectifier circuit includes a first diode assembly connected to the high-voltage winding, a first capacitor assembly disposed in parallel with the first diode assembly, and a resistor disposed in parallel with the first capacitor assembly. A first output terminal of the resistor is connected to the anode of the microwave oven magnetron, and a second output terminal of the resistor is connected to the cathode of the microwave oven magnetron. The filament winding is located on the high-voltage side of the transformer and is simultaneously connected to the first diode assembly and the first capacitor assembly. The second circuit includes an anode voltage sampling winding on the high-voltage side of the transformer and a second voltage doubler rectifier circuit connected to the anode voltage sampling winding. The first terminal of the second voltage doubler rectifier circuit is connected to the anode voltage sampling winding, and the second terminal of the second voltage doubler rectifier circuit is connected to the control unit. The second voltage doubler rectifier circuit includes a second diode assembly connected to the anode voltage sampling winding, a second capacitor assembly connected to the anode voltage sampling winding and arranged in parallel with the second diode assembly, and an inductor connected to both the second diode assembly and the second capacitor assembly. The first terminal of the inductor is connected to both the second diode assembly and the second capacitor assembly, and the second terminal of the inductor is connected to the control unit.

5. An electronic transformer for a microwave oven according to claim 4, characterized in that, The first diode assembly includes a first diode and a second diode connected in series; the first capacitor assembly includes a first capacitor and a second capacitor connected in series; the first end of the high-voltage winding is connected to the positive terminal of the first capacitor, the second capacitor, and the first diode, and the second end of the high-voltage winding is connected to the negative terminal of the second diode; the filament winding is connected to the positive terminal of the second diode and the first capacitor. The second diode assembly includes a third diode and a fourth diode connected in series; the second capacitor assembly includes a third capacitor and a fourth capacitor connected in series; the first end of the anode voltage sampling winding is connected to both the positive terminal of the third diode and the negative terminal of the fourth diode, and the second end of the anode voltage sampling winding is connected to both the third capacitor and the fourth capacitor; the first end of the inductor is connected to both the negative terminal of the third diode, the positive terminal of the fourth diode, and the fourth capacitor.

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