CN112020164B

CN112020164B - Radio frequency heating circuit and radio frequency heating equipment

Info

Publication number: CN112020164B
Application number: CN201910472921.0A
Authority: CN
Inventors: 张力潇; 俞国新; 丁剑波; 潘自杰; 叶世超; 沈兵
Original assignee: Qingdao Haier Co Ltd; Qingdao Haier Smart Technology R&D Co Ltd
Current assignee: Qingdao Haier Co Ltd; Qingdao Haier Smart Technology R&D Co Ltd
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2023-04-21
Anticipated expiration: 2039-05-31
Also published as: CN112020164A

Abstract

The application relates to a radio frequency heating circuit and radio frequency heating device, this radio frequency heating circuit includes: the device comprises a radio frequency source, an attenuator, a power amplifier and a radio frequency switch; the attenuator is connected with the radio frequency source and is configured to adjust the peak power of a radio frequency signal emitted by the radio frequency source to the rated input power of the power amplifier; the radio frequency switch is connected with the attenuator and is configured to modulate the radio frequency signal after peak value adjustment; the power amplifier is connected with the radio frequency switch and is configured to amplify the power of the modulated radio frequency signal to a set output power so as to meet the heating requirement. According to the embodiment of the disclosure, the peak power of the radio frequency signal is regulated to the rated input power of the power amplifier through the attenuator, and the radio frequency signal after peak regulation is modulated by combining the radio frequency switch, so that the power amplifier operates efficiently under the condition that the output power meets the heating requirement, and the energy utilization rate is improved.

Description

Radio frequency heating circuit and radio frequency heating equipment

Technical Field

The present application relates to the field of microwave technology, for example, to a radio frequency heating circuit and a radio frequency heating apparatus.

Background

At present, due to the advantages of low cost and small size of the semiconductor solid-state radio frequency source and the technical advantage of good controllability of radio frequency signals emitted by the semiconductor solid-state radio frequency source, more and more radio frequency heating devices adopt the solid-state radio frequency source to generate radio frequency energy signals for heating. The output power of the solid state radio frequency source can be adjusted within a set frequency range to meet the heating requirements of different objects. The radio frequency heating apparatus disclosed in the related art includes an adjustable attenuator, and the radio frequency power emitted by the radio frequency source is adjusted by the adjustable attenuator, so that the output power of the radio frequency heating apparatus meets different heating requirements.

In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art: the energy utilization rate of the radio frequency heating equipment is highest when the output power of the radio frequency heating equipment is rated output power, at the moment, the operation efficiency of the power amplifier is highest, but in order to meet different heating requirements in the process of adjusting the output power, the power amplifier in the radio frequency heating equipment cannot operate efficiently along with the reduction of the output power, so that the energy utilization rate of the radio frequency heating equipment is reduced.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview, and is intended to neither identify key/critical elements nor delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows.

The embodiment of the disclosure provides a radio frequency heating circuit and radio frequency heating equipment, so as to solve the problem that the energy utilization rate is reduced along with the reduction of the output power of the radio frequency heating equipment in order to meet different heating demands.

In some embodiments, the radio frequency heating circuit comprises a radio frequency source, an attenuator and a power amplifier and a radio frequency switch;

the attenuator is connected with the radio frequency source and is configured to adjust the peak power of the radio frequency signal emitted by the radio frequency source to the maximum rated output power of the power amplifier;

the radio frequency switch is connected with the attenuator and is configured to modulate the radio frequency signal after peak value adjustment;

the power amplifier is connected with the radio frequency switch and is configured to amplify the power of the modulated radio frequency signal to a set output power so as to meet the heating requirement.

In some embodiments, the radio frequency heating apparatus comprises a radio frequency heating circuit as described above.

The radio frequency heating circuit and the radio frequency heating equipment provided by the embodiment of the disclosure can realize the following technical effects:

the peak power of the radio frequency signal is regulated to the rated input power of the power amplifier through the attenuator, the radio frequency signal after peak regulation is modulated by combining with the radio frequency switch, so that the power amplifier operates efficiently under the condition that the output power meets the heating requirement, and the energy utilization rate is improved.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which like reference numerals refer to similar elements, and in which:

fig. 1 is a schematic diagram of a radio frequency heating circuit according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram of a RF heating circuit provided in an embodiment of the present disclosure;

FIG. 3 is a waveform diagram of a modulated wave and a radio frequency signal before and after modulation provided by an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a RF heating circuit provided in an embodiment of the present disclosure;

reference numerals:

101: a radio frequency source; 102: an attenuator; 103: a power amplifier; 104: a radio frequency switch; 105: a controller; 106: a circulator; 107: and protecting the resistor.

Detailed Description

So that the manner in which the features and techniques of the disclosed embodiments can be understood in more detail, a more particular description of the embodiments of the disclosure, briefly summarized below, may be had by reference to the appended drawings, which are not intended to be limiting of the embodiments of the disclosure. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown simplified in order to simplify the drawing.

In the process of applying the radio frequency heating device, the required heating power can be different according to the material, the volume or the application of the heated material. To meet different heating requirements, the power of the initial RF signal is different. According to different performances of the radio frequency heating device, rated input power of a power amplifier in the radio frequency heating device is different. The power amplifier operates most efficiently when the peak power of the signal input to the power amplifier is equal to the nominal input power of the power amplifier. When the peak power of the initial radio frequency signal is lower than that of the power amplifier, the power amplifier cannot operate with reduced efficiency, and the energy consumption is high, so that the energy utilization rate is reduced.

As shown in fig. 1, the radio frequency heating circuit provided in this embodiment includes a radio frequency source 101, an attenuator 102, a power amplifier 103, and a radio frequency switch 104.

Wherein the attenuator 102, coupled to the rf source 101, is configured to adjust the peak power of the rf signal emitted by the rf source 101 to the nominal input power of the power amplifier 103.

A radio frequency switch 104, coupled to the attenuator 102, is configured to modulate the peak-adjusted radio frequency signal.

The power amplifier 103 is connected to the rf switch 104 and configured to amplify the power of the modulated rf signal to a set output power to meet the heating requirement.

The attenuator 101 adjusts the peak power of the initial rf signal to maintain the power amplifier 103 operating at optimum operating efficiency. At this time, if a continuous rf signal is output to the power amplifier 103, the output power per unit time is increased, and the quality of the heated material is lowered when the heating requirement is exceeded. The radio frequency switch 102 modulates the power signal to obtain a modulated signal, and adjusts the output power to the set output power under the condition that the peak power of the modulated signal is equal to the rated input power of the power amplifier 103 and the power amplifier 103 operates efficiently.

According to the embodiment of the disclosure, the peak power of the radio frequency signal is regulated to the rated input power of the power amplifier through the attenuator, and the radio frequency signal after peak regulation is modulated by combining the radio frequency switch, so that the power amplifier operates efficiently under the condition that the output power meets the heating requirement, and the energy utilization rate is improved.

As shown in fig. 2, in some embodiments, the radio frequency heating circuit further comprises a controller 105.

Wherein the controller 105 is configured to acquire the modulated wave.

The radio frequency switch 104 is configured to modulate the peak-adjusted radio frequency signal according to the modulated wave.

The rf switch 104 modulates the rf signal after the peak adjustment, so as to ensure that the output power in unit time is equal to the set output power.

In some embodiments, the controller 105 is configured to generate the modulated wave according to the set output power and a rated output power of the radio frequency heating circuit.

The form of the modulation wave is various, and optionally, the modulation wave is one or more of sine wave, sawtooth wave and rectangular wave.

Optionally, one or more of pulse width or phase of the modulated wave is determined according to the set output power and rated output power of the radio frequency heating apparatus.

In some embodiments, as shown in fig. 3, the modulated wave is a rectangular wave.

And a controller 105 configured to determine a duty ratio according to the set output power and the rated output power, and generate the modulation wave according to the duty ratio.

In some embodiments, the duty cycle is determined from a set output power to rated output power ratio.

For example: when the rated output power of the radio frequency heating device is 1000W and the currently required heating power is 400W, the duty ratio is 40%; when the rated output power of the radio frequency heating device is 1000W and the currently required heating power is 500W, the duty ratio is 50%.

Specifically, as shown in fig. 3, the rf signal waveforms before and after modulation by the rf switch 104 are shown.

In some embodiments, the radio frequency switch 104 is further configured to control the operating state of the power amplifier 103 according to the modulated wave.

Taking the example of the modulated wave as a rectangular wave as shown in fig. 3, the power amplifier 103 is controlled to be in the power-on operation state when the rectangular wave signal is at a high level, and the power amplifier 103 is controlled to be in the power-off state when the rectangular wave signal is at a low level. Avoiding that the power amplifier 103 is in operation when the rectangular wave signal is at a low level increases the power consumption.

In some embodiments, the power amplifier 103 includes: a primary amplifier, a penultimate amplifier, and a final amplifier.

In some embodiments, radio frequency switch 104 is configured to control the operating state of one or more of the primary amplifier, the penultimate amplifier, and the final amplifier in accordance with the modulated wave.

In some embodiments, radio frequency switch 104 is configured to control the penultimate amplifier and the final amplifier according to the modulated wave. In the multistage amplifier in the power amplifier 103, the penultimate amplifier and the final amplifier consume larger direct current power, so that the state of the primary amplifier is not adjusted in order to reduce the energy consumed by the radio frequency heating device and avoid unstable current caused by frequent turning on and off of the power amplifier 103 and damage the power amplifier 103.

In some embodiments, attenuator 102 is configured to adjust the peak power of the radio frequency signal emitted by the radio frequency source to the rated input power of the penultimate amplifier or the final amplifier.

In some embodiments, as shown in this fig. 4, the radio frequency heating circuit further comprises: a circulator 106 and a protection resistor 107.

The circulator 106 is a device for unidirectional ring transmission of electromagnetic waves. The circulator 106 as in this fig. 4 includes port 1, port 2 and port 3. In the electromagnetic wave signal transmission process, a signal input from a 1 port is output from a 2 port, and a signal input from the 2 port is output from a 3 port, so that the electromagnetic wave unidirectional annular transmission is realized.

The circulator 106 is configured to send the power signal reflected by the heated space to the protection resistor 107, so that the power signal reflected by the heated space can be prevented from being transmitted to the power amplifier 103, and the working performance of the power amplifier 103 is prevented from being affected.

A protection resistor 107 configured to consume the power signal reflected back from the heated space. The resistance of the protection resistor 107 is matched with the impedance of the rf source 105, so as to improve the energy utilization rate of the rf heating device.

The embodiment of the disclosure also provides a radio frequency heating device, which comprises the radio frequency heating circuit provided by the embodiment. The radio frequency heating circuit is arranged between the heating cavity and the shell of the radio frequency heating equipment.

According to the radio frequency heating equipment provided by the embodiment of the disclosure, the peak power of the radio frequency signal is regulated to the rated input power of the power amplifier through the attenuator, and the radio frequency signal after peak regulation is modulated by combining the radio frequency switch, so that the power amplifier operates efficiently under the condition that the output power meets the heating requirement, and the energy utilization rate is improved.

In some embodiments, the radio frequency heating apparatus further comprises a power selection module.

Wherein, the power selection module is connected with the radio frequency switch 104 and configured to select a set output power. The rf switch 104 modulates the peak-adjusted rf signal according to the set output power.

In some embodiments, the power selection module is connected to the controller 105, and the controller 105 generates a modulation wave according to the set output power and the rated output power of the rf heating device, and the rf switch 104 modulates the rf signal after peak adjustment according to the modulation wave.

The radio frequency heating equipment provided by the embodiment of the disclosure is a microwave oven, a dryer or a thawing machine.

The above description and the drawings illustrate embodiments of the disclosure sufficiently to enable those skilled in the art to practice them. Other embodiments may involve structural, logical, electrical, process, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of others. The scope of the embodiments of the present disclosure encompasses the full ambit of the claims, as well as all available equivalents of the claims. When used in this application, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without changing the meaning of the description, so long as all occurrences of the "first element" are renamed consistently and all occurrences of the "second element" are renamed consistently. The first element and the second element are both elements, but may not be the same element. Moreover, the terminology used in the present application is for the purpose of describing embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" (the) are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, when used in this application, the terms "comprises," "comprising," and/or "includes," and variations thereof, mean that the stated features, integers, steps, operations, elements, and/or components are present, but that the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of other like elements in a process, method or apparatus comprising such elements. In this context, each embodiment may be described with emphasis on the differences from the other embodiments, and the same similar parts between the various embodiments may be referred to each other.

The embodiment of the present disclosure is not limited to the structure that has been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the embodiments of the present disclosure is limited only by the appended claims.

Claims

1. A radio frequency heating circuit comprising a radio frequency source, an attenuator, and a power amplifier, further comprising: a radio frequency switch;

the attenuator is connected with the radio frequency source and is configured to adjust the peak power of the radio frequency signal emitted by the radio frequency source to the rated input power of the power amplifier;

the power amplifier is connected with the radio frequency switch and is configured to amplify the power of the modulated radio frequency signal to a set output power so as to meet the heating requirement;

the radio frequency heating circuit further comprises: a controller configured to acquire a modulated wave;

the controller is configured to determine a duty cycle according to the set output power and the rated output power, and generate the modulation wave according to the duty cycle; the radio frequency switch is configured to modulate the radio frequency signal subjected to peak adjustment according to the modulation wave;

the power amplifier includes: a primary amplifier, a penultimate amplifier, and a final amplifier;

the radio frequency switch is configured to control the penultimate amplifier and the final amplifier in accordance with the modulated wave.

2. The circuit of claim 1, wherein the modulated wave is a rectangular wave.

3. The circuit of claim 1, wherein the attenuator is configured to adjust a peak power of a radio frequency signal emitted by the radio frequency source to a rated input power of the penultimate amplifier or the final amplifier.

4. A radio frequency heating apparatus comprising the radio frequency heating circuit of any one of claims 1 to 3; the radio frequency heating circuit is arranged between the heating cavity and the shell of the radio frequency heating equipment.

5. The apparatus as recited in claim 4, further comprising:

and the power selection module is connected with the radio frequency switch and is configured to select and set the output power.