Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/66—Circuits
  • H05B6/68—Circuits for monitoring or control
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

• Microwave ovens and semiconductor power sources for microwave ovens are Microwave ovens and semiconductor power sources for microwave ovens
• the present invention relates to the field of semiconductor microwave technology, and more particularly to a semiconductor power source for a microwave oven and a microwave oven having a semiconductor power source. Background technique
• the current magnetron microwave oven is shown in FIG. 1 and includes a magnetron tube, a microwave oven chamber 2, a control system 3, and a power source 4, which has high cost, large volume, large weight, high voltage, etc.
• the main components of the magnetron microwave oven include magnetrons, high voltage transformers, high voltage capacitors, high voltage diodes, rectangular waveguides, cavities, furnace doors and control sections.
• the AC power supply provides a filament voltage to the magnetron via a high voltage transformer. After the AC power is boosted by the high voltage transformer, the high voltage capacitor and the high voltage diode, it becomes a DC pulsating high voltage, and the magnetron can emit microwave. After the microwave enters the cavity of the microwave oven through the rectangular waveguide, it acts on the heated substance in the cavity to realize rapid microwave heating.
• microwaves In addition to the ability of the magnetron to emit microwaves, semiconductor devices are currently capable of emitting microwaves.
• the existing semiconductor microwave technology is mainly used for communication, and the main difference between the microwave used for communication and the microwave used for heating is that the frequency band of the microwave is different.
• microwave efficiency of semiconductors is getting higher and higher, the cost is getting lower and lower, the weight is getting lighter, and the power density per unit volume is getting larger and larger.
• the application in microwave oven is semiconductor microwave. The inevitable trend of technological development.
• the microwave power sources currently studied in semiconductor microwave ovens are all using the source and amplification principle. In practical applications, the cost is high and the system is complicated. In particular, the source part needs to use a dedicated module, and the design and development difficulties are difficult. And the amplification part is a two-stage amplification, that is, the first small signal amplification and the second amplification.
• the prior art semiconductor microwave oven includes a semiconductor power source 10, a microwave oven cavity 20, a control system 30, and a power source 40.
• the power source 40 supplies power to the semiconductor power source 10, and the semiconductor power source 10 sends a microwave of 2400 MHz to 2500 MHz into the microwave oven cavity 20 to heat the food in the furnace chamber 20. As shown in FIG.
• a common semiconductor power source includes a power source 40, a signal source 13, a first stage amplifier 11 and a second stage amplifier 12, wherein the signal source 13 generates a microwave signal of 2400 MHz to 2500 MHz and outputs it to the first stage amplifier 11.
• the 2400MHz ⁇ 2500MHz microwave signal is amplified by the first-stage amplifier 11 into a low-power microwave signal, and then input to the secondary amplifier 12 to obtain a high-power microwave output.
• the magnitude and quality of the microwave output power depend on the performance of the two-stage amplifier, and the frequency depends on the frequency of the signal source 13 being emitted.
• the source and amplification principle of the semiconductor microwave source is more suitable for the microwave signal requirements of the communication industry, and the microwave linearity is not very high for the 2400MHz ⁇ 2500MHz microwave signal used for heating.
• the magnetron microwave oven has disadvantages such as high cost, large volume, large weight, and high voltage
• the existing semiconductor microwave oven has the disadvantages of high cost, complicated system, and difficulty in independent design and development. Summary of the invention
• the object of the present invention is to at least solve one of the above technical problems.
• the object of the present invention is to provide a semiconductor power source for a microwave oven and a microwave oven having the semiconductor power source, which has a simple and reasonable structure, low manufacturing cost, and high reliability to overcome the prior art. Inadequacies.
• a first aspect of the present invention provides a semiconductor power source for a microwave oven, the semiconductor power source including a bias voltage and control module, a power detection module, a power combiner, and a plurality of LDMOS transistors, wherein The gates of the plurality of LDMOS transistors are connected in parallel to the bias voltage and control module, the sources of the plurality of LDMOS transistors are common, and the drains of the plurality of LDMOS transistors are connected in parallel with the power synthesis Connected to the plurality of LDMOS tubes to generate microwaves of a preset frequency according to the self-oscillation circuit; the power combiner for adjusting the plurality of An output impedance of the LDMOS transistor, and controlling a phase of the wave outputted by the plurality of LDMOS transistors to be the same; the power detecting module, configured to detect a reflected power and an output power of the semiconductor power source, according to the reflected power and the output power Generating a detection signal and transmitting the detection
• control system outputs a frequency adjustment signal to the bias voltage and control module to adjust the heating frequency of the semiconductor power source.
• control system further outputs a voltage adjustment signal to control an output power of the semiconductor power source.
• the power detection module includes: a first resistor, one end of the first resistor is connected to a signal end of the reflected power; a first control chip, the first control The third pin of the chip is connected to the other end of the first resistor, the fourth pin and the fifth pin of the first control chip are connected to be grounded, and the second pin of the first control chip is grounded; a second resistor, one end of the second resistor is connected to one end of the first resistor, and the other end of the second resistor is connected to a sixth pin of the first control chip; One end of the third resistor is grounded, and the other end of the third resistor is connected to the first pin of the first control chip; the first capacitor, one end of the first capacitor and the sixth of the first control chip respectively a pin is connected to the other end of the second resistor; a fourth resistor, one end of the fourth resistor is connected to the other end of the first capacitor, and the other end of the fourth resistor is respectively connected to the first control First chip
• the pin is
• the power detection module further includes: a second control chip, wherein the fourth pin and the fifth pin of the second control chip are connected to be grounded, and the second pin of the second control chip is grounded; a capacitor, one end of the second capacitor is connected to a sixth pin of the second control chip; a fifth resistor, one end of the fifth resistor is connected to the other end of the second capacitor, and the other end of the fifth resistor is connected to the first pin of the second control chip; a sixth resistor, the first One end of the six resistor is connected to the first pin of the second control chip, the other end of the sixth resistor is grounded; the seventh resistor, one end of the seventh resistor and the sixth tube of the second control chip The other end of the seventh resistor is connected to the signal end of the output power; the eighth resistor, one end of the eighth resistor is connected to the third pin of the second control chip, the eighth The other end of the resistor is connected to the other end of the seventh resistor.
• the bias voltage and control module further includes: a ninth resistor and a Zener diode connected in series, a positive terminal of the Zener diode is grounded, and one end of the ninth resistor is opposite to the semiconductor a DC power input end of the power source is connected; a third capacitor, one end of the third capacitor is connected to one end of the ninth resistor, and the other end of the third capacitor is grounded; a variable capacitor, the variable capacitor One end is connected to one end of the ninth resistor, the other end of the variable capacitor is grounded, a control end of the variable capacitor is connected to the control system; a triode, an emitter of the triode and the ninth resistor Connected to a node between the Zener diodes; a tenth resistor, one end of the tenth resistor is connected to the control system, and the other end of the tenth resistor is connected to a base of the triode; One end of the variable resistor is connected to the collector of the triode, and the other end of the
• a microwave oven includes: a microwave oven cavity; the semiconductor power source for a microwave oven described above, for generating a microwave of a preset frequency; a control system, the control system and The semiconductor power source is connected to adjust an output power and a heating frequency of the semiconductor power source to control heating of food in the microwave oven cavity; a DC power source, the DC power source and the semiconductor power source and the control respectively A system is coupled for powering the semiconductor power source and the control system.
• the microwave generating structure of the semiconductor power source is performed Simplification, reduced cost, improved reliability, simple and reasonable structure, low production cost, and good reliability.
• control system output voltage adjustment signal adjusts an output voltage of the DC power source to control an output power of the semiconductor power source.
• the microwave of the preset frequency ranges from 2400 MHz to 2500 MHz.
• FIG. 1 is a schematic structural view of a conventional magnetron microwave oven
• FIG. 2 is a schematic diagram of control of a conventional semiconductor microwave oven
• FIG. 3 is a schematic diagram of a semiconductor power source of the conventional general amplification principle
• FIG. 5 is a schematic diagram of a control system of a microwave oven according to an embodiment of the present invention
• FIG. 6A is a diagram showing power consumption of a power detection module according to an embodiment of the present invention. Detecting part of the circuit diagram
• 6B is a circuit diagram of a power detecting module for an output power detecting portion according to an embodiment of the present invention.
• FIG. 7 is a circuit diagram of a bias voltage and control module in accordance with an embodiment of the present invention. and an intent.
• a magnetron microwave oven a magnetron, a microwave oven 2, a control system 3, and a power source 4;
• semiconductor power source 10 of the present invention bias And a control module 41, a power detecting module 42, a power combiner 43 and a plurality of LDMOS transistors (44, 45 N ), a first resistor R1, a first control chip U1, a second resistor R2, a third resistor R3, and a first capacitor And a fourth resistor R4, a second control chip U2, a second capacitor C2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, a ninth resistor R9, a Zener diode Dl, a third capacitor C3, variable capacitor C4, transistor Q1, tenth resistor R10, variable resistor R12 and eleventh resistor R11; in the furnace of the present
• the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the applicability of other processes and/or the use of other materials.
• the structure of the first feature described below "on" the second feature may include embodiments in which the first and second features are formed in direct contact, and may include additional features formed between the first and second features. The embodiment, such that the first and second features may not be in direct contact.
• a source of source and a microwave oven having the semiconductor power source having the semiconductor power source.
• the semiconductor power source for a microwave oven proposed by the first aspect of the present invention includes a bias voltage and control module 41, a power detecting module 42, a power combiner 43, and a plurality of LDMOS (Lateral Diffused Metal Oxide Semiconductor, Lateral diffusion metal oxide semiconductor) tube (44, 45 N ).
• N can range from 44-54.
• the gates of the plurality of LDMOS transistors (44, 45 N ) are connected in parallel to the bias voltage and control module 41, and the plurality of LDMOS transistors (44, 45)
• the source of N) is common, the drains of the plurality of LDMOS transistors (44, 45 N ) are connected in parallel to the power combiner 43 , and the plurality of LDMOS transistors ( 44 , 45 N ) generate microwaves of a preset frequency according to the self-oscillation circuit. .
• the microwave of the preset frequency ranges from 2400 MHz to 2500 MHz.
• the output ends of the plurality of LDMOS transistors (44, 45 N ) are connected to the power combiner 43 through capacitors, and the output impedances of the plurality of LDMOS transistors (44, 45 N ) are connected in parallel, and the power combiner 43 is used to adjust multiple
• the output impedance of the LDMOS transistor (44, 45 N ) for example, the power combiner 43 can adjust the impedance to a 50 ohm output, and simultaneously control the phases of the waves output by the plurality of LDMOS transistors (44, 45 N ) to the same level and together, Helps reduce losses.
• the power detection module 42 is configured to detect the reflected power and output power of the semiconductor power source, generate a detection signal based on the reflected power and the output power, and transmit the detection signal to a control system of the microwave oven.
• the bias voltage and control module 41 is used for multiple LDMOS tubes (44, 45)
• N provides a bias voltage and adjusts the bias voltage to adjust the heating frequency and output power of the semiconductor power source under the control of the microwave oven's control system.
• the control system 51 of the microwave oven outputs a semiconductor power source turn-off signal C , a semiconductor power source adjustment signal E to a bias voltage and control module 41 to regulate the heating of the semiconductor power 50.
• the frequency which enables the heating frequency to vary between 2400 MHz and 2500 MHz.
• the control system 51 of the microwave oven also outputs a voltage adjustment signal D to regulate the output voltage of the DC power source 52 to control the output power of the semiconductor power source 50.
• the output voltage varies between DC0-32V.
• the power detecting module 42 outputs the semiconductor power source output power detecting signal A and the semiconductor power source reflected power detecting signal B to the control system 51 of the microwave oven.
• the power detecting module 42 includes a first resistor R1, a first control chip U1, a second resistor R2, a third resistor R3, and a A capacitor and a fourth resistor R4. Wherein one end of the first resistor R1 is connected to the signal end of the reflected power.
• the third pin 3 of the first control chip U1 is connected to the other end of the first resistor R1.
• the fourth pin 4 and the fifth pin 5 of the first control chip U1 are connected to each other and grounded.
• the second control chip U1 is second. Pin 2 is grounded.
• One end of the second resistor R2 is connected to one end of the first resistor R1, and the other end of the second resistor R2 is connected to the sixth pin 6 of the first control chip U1.
• One end of the third resistor R3 is grounded, and the other end of the third resistor R3 is connected to the first pin 1 of the first control chip U1.
• One end of the first capacitor C1 is respectively connected to the other end of the sixth pin 6 and the second resistor R2 of the first control chip U1, and one end of the fourth resistor R4 is connected to the other end of the first capacitor C1, and the fourth resistor R4 is The other end is connected to the other end of the first pin 1 and the third resistor R3 of the first control chip U1, respectively.
• the power detecting module 42 detects the output power.
• the sub-controller further includes a second control chip U2, a second capacitor C2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8.
• the fourth pin 4 and the fifth pin 5 of the second control chip U2 are connected to each other and grounded, and the second pin 2 of the second control chip U2 is grounded.
• One end of the second capacitor C2 is connected to the sixth pin 6 of the second control chip U2, one end of the fifth resistor R5 is connected to the other end of the second capacitor C2, and the other end of the fifth resistor R5 is connected to the second control chip U2.
• the first pin 1 is connected.
• One end of the sixth resistor R6 is connected to the first pin 1 of the second control chip U2, and the other end of the sixth resistor R6 is grounded.
• One end of the seventh resistor R7 is connected to the sixth pin 6 of the second control chip U2, and the other end of the seventh resistor R7 is connected to the signal end of the output power.
• One end of the eighth resistor R8 is connected to the third pin 3 of the second control chip U2, and the other end of the eighth resistor R8 is connected to the other end of the seventh resistor R7.
• the power detection module 42 couples the output power and reflected power of each LDMOS transistor by the directional coupling principle, and then converts it into an output voltage supply control system 51 through the control chips U1 and U2.
• the bias voltage and control module 41 further includes a ninth resistor R9, a Zener diode D1, a third capacitor C3, a variable capacitor C4, a transistor Q1, and a tenth resistor R10. , a variable resistor R12 and an eleventh resistor Rl l.
• the ninth resistor R9 and the Zener diode D1 are connected in series, and the positive terminal of the Zener diode D1 is grounded, and one end of the ninth resistor R9 is connected to the DC power input end of the semiconductor power source 50 (for example, +32V).
• One end of the third capacitor C3 is connected to one end of the ninth resistor R9, the other end of the third capacitor C3 is grounded, one end of the variable capacitor C4 is connected to one end of the ninth resistor R9, and the other end of the variable capacitor C4 is grounded, variable The control terminal of capacitor C4 is coupled to control system 51 (semiconductor power source adjustment signal E).
• the emitter of the transistor Q1 is connected to a node between the ninth resistor R9 and the Zener diode D1, and one end of the tenth resistor R10 is connected to the control system 51 (semiconductor power source turn-off signal C), and the other end of the tenth resistor R10 is
• the base of the transistor Q1 is connected, one end of the variable resistor R12 is connected to the collector of the transistor Q1, and the other end of the variable resistor R12 is grounded.
• One end of the eleventh resistor R11 is connected to the control terminal of the variable resistor R12, and the other end of the eleventh resistor R11 is connected to the gates of the plurality of LDMOS transistors, respectively.
• the 32V DC power input is converted to 5V through the Zener diode D1 and its series resistor R9, and then the voltage output of about 2.5V is realized by the variable resistor R12.
• the triode Q1 is connected in series with the 5V circuit output of the Zener diode D1 and its series resistor R9, and the semiconductor power source shutdown signal c is output through the control system 51 to control the switch of the transistor Q1 to realize the gate voltage control of the supply LDMOS transistor. , control the switch of each LDMOS tube.
• variable digital variable capacitor C4 which is serially connected between the 32V DC power source and the ground, outputs a semiconductor power source adjustment signal E through the control system 51 to adjust the change of the variable capacitor C4. Thereby adjusting the operating frequency of the semiconductor power source.
• the bias voltage and control module 41 and the power detecting module 42 all use simple components such as resistors, capacitors, etc., the circuit structure is simple, the loss is small, the cost is greatly reduced, and the reliability is improved.
• the working principle of the semiconductor power source 50 based on the principle of oscillating microwave generation in the embodiment of the present invention is as follows:
• the LDMOS tube generates a microwave with a frequency of 2450 MHz and 50 MHz through a self-oscillation circuit, and the magnitude of the microwave power is determined by the power of the LDMOS tube. The number is determined.
• the variable capacitance value of the self-oscillating circuit the frequency can also be changed.
• the cavity standing wave ratio is selected in the range of 2400 MHz to 2500 MHz. The minimum frequency of the standing wave is heated. Adding simplicity, greatly reducing costs and increasing reliability.
• a microwave oven according to an embodiment of the second aspect of the present invention includes a microwave oven cavity 80, the above-described semiconductor power source 50 for a microwave oven, a control system 51, and a DC power source 52.
• the semiconductor power source 50 is used to generate microwaves of a preset frequency.
• the microwave of the preset frequency ranges from 2400 MHz to 2500 MHz.
• a control system 51 is coupled to the semiconductor power source 50 for regulating the output power and heating frequency of the semiconductor power source 50 to control the heating of the microwave oven. Food within the cavity 80.
• a DC power source 52 is coupled to the semiconductor power source 50 and the control system 51 for powering the semiconductor power source 50 and the control system 51, respectively.
• the power supply 40 in FIG. 2 is rectified to obtain a DC power supply 52.
• the DC power supply 52 outputs a variable DC voltage DC 0-32V to the semiconductor power source 50, and the DC power supply 52 is simultaneously output.
• the DC voltage DC 12V and the DC voltage DC 5V are supplied to the control system 51, and the control system 51 outputs a voltage adjustment signal D to the DC power source 52 to adjust the voltage value of the variable DC voltage DC 0-32V output from the DC power source 52, thereby controlling the semiconductor.
• the output power of the power source 50 is supplied to the control system 51, and the control system 51 outputs a voltage adjustment signal D to the DC power source 52 to adjust the voltage value of the variable DC voltage DC 0-32V output from the DC power source 52, thereby controlling the semiconductor.
• the required voltage of the semiconductor power source 50 is DC 0-32V.
• the microwave output power of the semiconductor microwave source 50 can be adjusted, and the power of the microwave oven can be steplessly adjusted.
• the microwave generating structure of the semiconductor power source 50 is simplified, the cost is reduced, the reliability performance is improved, and the structure is simple and reasonable, the manufacturing cost is low, and the reliability is good.

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• Control Of High-Frequency Heating Circuits (AREA)
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• 2012
  • 2012-05-21 CN CN201210159268.0A patent/CN102679417B/zh active Active
  • 2012-10-23 WO PCT/CN2012/083384 patent/WO2013174097A1/fr not_active Ceased

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