CN1707928A - Microwave oven magnetron working electric power source - Google Patents
Microwave oven magnetron working electric power source Download PDFInfo
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- CN1707928A CN1707928A CN 200410024251 CN200410024251A CN1707928A CN 1707928 A CN1707928 A CN 1707928A CN 200410024251 CN200410024251 CN 200410024251 CN 200410024251 A CN200410024251 A CN 200410024251A CN 1707928 A CN1707928 A CN 1707928A
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Abstract
The present invention discloses one kind of power supply for magnetron in light domestic microwave oven, and belongs to the field of microwave heating technology. The power supply consists of industrial frequency rectifier and filter circuit to convert AC electric supply into DC power source, power converter of HF switching circuit to convert the DC power source into HF high voltage power source, HF rectifier and filter circuit to convert the HF high voltage power source into DC high voltage power source, and magnetron filament power source. The present invention has the advantages of reduced microwave oven weight, easy packing and transportation, low power consumption, environment friendship and low production cost.
Description
Technical field
The invention discloses a kind of power supply of lightweight household microwave oven magnetron, belong to the microwave heating technique field.
Background technology
Before the present invention made, the magnetron working power of household microwave oven was made up of power frequency high voltage transformer and rectifying device.Earlier electric main is boosted, pass through rectifying device again with the High Level AC Voltage rectifying and wave-filtering, form the pulse dc high voltage electricity and supply with anode of magnetron, the filament supply of magnetron is supplied with by the low pressure winding of transformer.Because the power of microwave oven is more than 600W, thus the capacity of high-tension transformer generally more than 1KVA, thereby the volume of transformer is big, quality is big, makes the finished product gross mass of household microwave oven all more than 10KG.Not only waste a large amount of copper, ferrous metal resource, also increased cost of transportation.And the user moves inconvenience in use, and power-efficient is on the low side, be easy to generate the power frequency noise pollution, can bring worry to the user.
Summary of the invention
The present invention is directed to the deficiency of prior art, provide that a kind of quality is little, the microwave oven magnetic working power of power conversion efficient height, no power frequency noise.
The present invention's design is the AC power rectifier filter to be set electric main is transformed into direct current, utilize high-frequency switch circuit that direct current is transformed into high-frequency pulse current, on the high-frequency switch circuit loading coil, obtain the self-induction high-frequency high-voltage, obtain high voltage supply anode of magnetron more than the 2KV through the rectifier filter rectification.
Based on above invention thought, microwave oven magnetic working power basic comprising comprises:
1, can be direct current with the electric main rectification, the industrial frequency rectifying filter circuit of working power is provided for high-frequency switch circuit;
2, working power is provided, the direct current of rectifier filter output is transformed into the high-frequency switch circuit of high-frequency high-voltage by the industrial frequency rectifying filter circuit, also can be described as the supply convertor circuit;
3, with the high-frequency high-voltage of supply convertor circuit output, rectification is the filtering high-frequency rectifier device circuit of dc high-voltage;
4, with the filament power supply of the joining feeder line of magnetron and magnetron.
The industrial frequency rectifying filter circuit can adopt full wave bridge rectifier circuit and capacitor filter to form.
The supply convertor circuit can adopt transistor switching circuit, and energisation mode is self-excitation or separate excitation.The load of transistor switching circuit is an inductance coil, also can adopt the high frequency transformer of 20KHZ-100KHZ.
Filtering high-frequency rectifier device circuit can adopt crystal diode half-wave or full-wave rectifying circuit, also can adopt multiple rectifier circuit, and filter is a capacitive filter.
The filament power supply of magnetron can adopt the high frequency low voltage electricity of supply convertor circuit output, also can adopt the power frequency low-tension supply power supply of small power transformer output.
Below introduce structure of the present invention in detail, a kind of microwave oven magnetic blank pipe working power is characterized in that by can being galvanic industrial frequency rectifying filter circuit with the electric main rectification; Connect the industrial frequency rectifying filter, working power is provided, the direct current of industrial frequency rectifying filter output is transformed into the supply convertor that the high-frequency switch circuit of high-frequency high-voltage is formed by the industrial frequency rectifying filter circuit; Joining power converter circuit output, with the high-frequency high-voltage of supply convertor circuit output, rectification is constituted by the filtering high-frequency rectifier device circuit and the magnetron heater power supply of dc high-voltage.
High-frequency switch circuit is made up of high-power crystal switching tube and load inductance coil thereof.The discontinuous current of coil medium-high frequency passes through, and the coil two ends will produce self induction electromotive force.The height of voltage depends on the current changing rate in the circuit.The size of electric current is relevant with the equiva lent impedance of coil L in the loop: equiva lent impedance minor loop electric current more is big more, that is to say under the constant situation of frequency, the diameter of coil thick more (dc impedance is more little), inductance value more little (AC impedance is little), loop current and power output are also big more.
Experiment showed, that it also is a way that improves output voltage that the raising operating frequency reduces the electric current transformation period.Among the present invention, high-frequency switch circuit adopts the operating frequency of 20KHZ-40KHZ, can make the performance (usefulness, cost etc.) of circuit reach optimum.Can further reduce cost as selecting for use of switching tube with selecting for use all of high-frequency inductor coil.Inductance coil is the solid-iron oxysome, can be provided with the secondary coil winding above and provide electric current to magnetron heater.High-power crystal switching tube average current will select for use electric current bigger during actual the use more than 6A, and requirement of withstand voltage is higher, and the microwave oven drain pan can be directly selected in its heat radiation for use.
The high-pressure section that high-frequency switch circuit produces also can directly produce from the secondary winding on the inductance coil, the operation principle of circuit and structure are the same substantially, secondary winding L1 produces microwave oven magnetic excitation high pressure, secondary winding L2 produces the filament voltage of magnetron, the exciting signal frequency of high-power crystal switching tube can be brought up to more than the 40KHZ in this circuit, withstand voltage and the inductance coil of switching tube (should be called switch transformer this moment) volume can advance one one and reduce, and cost and volume weight also all can reduce or reduce.
The energisation mode of transistor switching circuit is self-excitation or separate excitation.The mode of self-excitation can adopt the mode of inductive feedback; The separate excitation mode can adopt the square-wave signal source circuit as drive(r) stage.
Advantage of the present invention is: 1, use electronic device to substitute the Industrial Frequency Transformer of traditional thick heaviness, alleviate the quality that has the microwave oven complete machine now greatly, the weight of this circuit is the 1/5-1/10 of transformer weight only, makes the microwave oven complete machine be convenient to packing, transportation etc.; 2, energy-saving and noise-reducing, environmental protection.Adopt electronic device, replace original transformer, reduce the consumption of metals resources such as iron, copper greatly, improved power conversion efficient simultaneously, reduce the complete machine work noise, more can not produce noise because of power frequency magnetic field attracts outer cover of steel plate; 3, the cost of entire circuit is lower than the cost of original high pressure Industrial Frequency Transformer, can effectively reduce production costs.Can substitute traditional microwave oven and promote the use of, have good economic benefit and environmental protection social benefit.
Description of drawings
Figure of description 1 is a block diagram of the present invention, Figure of description 2 is block diagram of the embodiment of the invention 1, Figure of description 3 is circuit theory diagrams of the embodiment of the invention 1, Figure of description 4, Fig. 5 are the circuit diagrams of the variable frequency square-wave generator of the embodiment of the invention 1, and accompanying drawing 6 is the electrical schematic diagrams that constitute exciting signal source in the high-grade microwave oven of microcomputerized control with Switching Power Supply managing chip LM3842.Accompanying drawing 7 is circuit diagrams that embodiment 3 is used to be provided with the microwave oven of switch transformer.Among the figure: A industrial frequency rectifying filter, B-source converter, C filtering high-frequency rectifier device, D filament power supply, E magnetron, F adjustable frequency square-wave generator, G Voltage Feedback control circuit.
Embodiment
Embodiments of the invention 1 are referring to accompanying drawing 2,3,4,5.
This embodiment is used for general economical microwave oven.
A kind of microwave oven magnetic working power is characterized in that by being galvanic industrial frequency rectifying filter A circuit with the electric main rectification; Connect industrial frequency rectifying filter A, working power is provided, the direct current of industrial frequency rectifying filter output is transformed into the supply convertor B that the high-frequency switch circuit of high-frequency high-voltage is formed by the industrial frequency rectifying filter circuit; Joining power converter B circuit output end, with the high-frequency high-voltage of supply convertor circuit output, rectification is constituted by the filtering high-frequency rectifier device C circuit and the magnetron heater power supply of dc high-voltage.
The microwave oven magnetic working power of economical microwave oven is characterized in that by being galvanic industrial frequency rectifying filter A circuit with the electric main rectification; Connect industrial frequency rectifying filter A, working power is provided, direct current is transformed into the supply convertor B that the high-frequency switch circuit of high-frequency high-voltage is formed by industrial frequency rectifying filter A circuit; Joining power converter B circuit output end, high-frequency high-voltage with the output of supply convertor B circuit, rectification is that the filtering high-frequency rectifier device C circuit of dc high-voltage constitutes: the output of the input of supply convertor B and an adjustable frequency square-wave generator F circuit links, and constitutes separated exciting variable frequency high-frequency switch circuit; Its output connects thermistor, and thermistor and adjustable frequency square-wave generator F circuit link, and forms the Voltage Feedback control circuit; The loading coil of supply convertor B circuit is connected with the filament of magnetron E by auxiliary winding and forms filament power supply D.
Supply convertor B forms transistor switching circuit by high-power crystal switching tube and load inductance coil.
Adjustable frequency square-wave generator F circuit can adopt RC or LC oscillating circuit, requires this circuit to have highly reliable stability, and square wave output is stable, can make the safe and reliable work of oscillating circuit, also makes system's output voltage stabilization.The power consumption of this element circuit little (5V/10MA), its working power can be made of through resistance and voltage stabilizing didoe voltage stabilizing series connection the industrial frequency rectifying filter circuit.Also can adopt independent small power transformer power supply.
Adjustable frequency square-wave generator F circuit comprises that a triangular wave oscillator circuit and operation amplifier circuit constitute: time-base circuit 555 constitutes the triangular wave oscillator circuit, realize variable frequency by the capacity that changes the capacitor C2 that output connects, the output of triangular wave oscillator circuit connects discharge circuit and forms square wave generation circuit.High-voltage output end feeds back signal to the discharge circuit control end, finely tunes weekly the phase duty ratio and realizes the stable of output voltage.
Adjustable frequency square-wave generator F channel frequency is 20KHZ-40KHZ, resistance R and thermistor RT form feedback circuit, (predetermined voltage mainly is that the parameter by exciting signal source and switch oscillating circuit decides when the voltage of oscillating circuit output is higher than when presetting voltage, feedback circuit can only be finely tuned), the voltage that M is ordered also can raise, after operational amplifier is handled, the effective duty ratio of square wave of output will reduce, oscillating circuit is under the constant situation of working oscillation frequency, the ON time of switching tube diminishes, output voltage also diminishes, vice versa, output voltage is comparatively stable all the time, and is not subjected to the interference of grid voltage change, has improved the voltage adaptation of microwave oven itself; Be thermistor because of the RT in the feedback circuit simultaneously, after microwave oven work a period of time, magnetron will generate heat, and power output also can reduce, and can suitably improve output voltage, the output frequency of stabilized magnetron by the compensating action of thermistor this moment.
Thermistor RT forms feedback circuit and promptly can pick out from filtering high-frequency rectifier device output, also can pick out the other end ground connection of filament power supply coil behind diode rectification from a power end of coil of filament.To avoid the connecting problems of bringing such as step-down power loss with high tension loop.
Industrial frequency rectifying filter A circuit adopts full-wave bridge rectifier element and electrolytic capacitor to constitute current rectifying and wave filtering circuit.For fear of the impact of the electric current of surging, can consider the current stabilization components and parts of connecting.
Filtering high-frequency rectifier device C circuit is formed current rectifying and wave filtering circuit by rectifier diode and high-voltage capacitance, because the concussion ac high-voltage frequency of exporting in the circuit is higher, and higher efficiency according to circuit, adopt halfwave rectifier and utilize high-voltage diode on the original microwave oven, the filtering capacitor capacity can also reduce in the hope of reducing cost.
The operation principle of present embodiment is with reference to the power line input of accompanying drawing 3:220V alternating current through microwave oven, through the rectification of D1-D4 bridge rectifier.The square wave that signal H1 provides 20～40KHZ for switching tube Q makes astragal L1 and switching tube Q constitute high-frequency switch circuit.Energy storage characteristics according to coil L1, to produce the vibration high pressure at the M point, after the unidirectional output of D diode again through C2 filtering, just there is the high direct voltage output of 2KV～4KV at the B place, this high pressure directly offers the driving voltage of magnetron, L1 has the another one auxiliary winding, and (frequency 20～40KHZ) offers magnetron and makes filament drive voltage can to export the alternating voltage of 3.3V.The height of high direct voltage of output has direct relation with the resonance frequency of H1 and the inductance value of L1, and frequency height, inductance value are big, and output voltage is also high; The power decision output current voltage of the diameter of coil L1 and switching tube Q and the power of filament alternating voltage, diameter power thick and switching tube Q is big, and power output is also just big.After the alternating current 220V input, through industrial frequency rectifying filter A circuit rectifying and wave-filtering, become the 300V direct current, adjustable frequency square-wave generator circuit F provides the square wave of 20～40KHZ for supply convertor B circuit, the switching circuit work of supply convertor B circuit, produce high pressure, after the output of filtering high-frequency rectifier device circuit D rectifying and wave-filtering, the high direct voltage that 2K-4KV is provided is to magnetron E, in addition, supply convertor B circuit have output 3.3V alternating voltage (frequency 20～40KHZ) offers magnetron and makes filament drive voltage.
Embodiments of the invention 2 are referring to accompanying drawing 2,3,6.
This embodiment is used for the high-grade microwave oven of microcomputerized control.Its pumping signal is referring to accompanying drawing 6, feature is that adjustable frequency square-wave generator F circuit provides pulse signal source by the Switching Power Supply managing chip on the computer control board, connects photoelectricity isolating interface and current pulse width modulation device integrated circuit UC3842 and constitutes exciting signal source.Pulse signal is taken place by computer chip, and can carry out frequency change by actual needs power, can be used the frequency conversion magnetron, forms the variable frequency microwave stove.The voltage feedback signal of high pressure output can be delivered to integrated circuit UC3842 and handle, and with the duty of adjusting weekly phase signal regulated output voltage recently, controls respond well.
Embodiment 3 is referring to accompanying drawing 7.
This embodiment is a kind of microwave oven of application switch transformer.It is characterized in that supply convertor B connects the load switch transformer by the high-power crystal switching tube and forms transistor switching circuit.The advantage of this structure is to utilize the number of turn of the secondary high pressure coil of switch transformer, adjusts high pressure output.Its signal source adopts fixed frequency, and operating frequency can reach 100KHZ, thereby the efficient of switch transformer can be higher, and volume and quality can further reduce.
Claims (9)
1, a kind of microwave oven magnetic working power is characterized in that by being galvanic industrial frequency rectifying filter (A) circuit with the electric main rectification; Connect industrial frequency rectifying filter (A), working power is provided, the direct current of industrial frequency rectifying filter output is transformed into the supply convertor (B) that the high-frequency switch circuit of high-frequency high-voltage is formed by the industrial frequency rectifying filter circuit; Joining power converter (B) circuit output end, with the high-frequency high-voltage of supply convertor circuit output, rectification is constituted by filtering high-frequency rectifier device (C) circuit and the magnetron heater power supply of dc high-voltage.
2, magnetron working power according to claim 1 is characterized in that the input of supply convertor (B) and the output of an adjustable frequency square-wave generator (F) circuit link, and constitutes separated exciting variable frequency high-frequency switch circuit; Its output connects thermistor, and thermistor and adjustable frequency square-wave generator (F) circuit link, and forms the Voltage Feedback control circuit.
3, microwave oven magnetic working power according to claim 1, it is characterized in that supply convertor (B) circuit power converter (B) is made up of high-power crystal switching tube and inductance coil, inductance coil has auxiliary winding to be connected with the filament of magnetron (E) to form filament power supply (D).
4, microwave oven magnetic working power according to claim 1, it is characterized in that adjustable frequency square-wave generator (F) circuit comprises that a triangular wave oscillator circuit and operation amplifier circuit constitute: time-base circuit 555 constitutes the triangular wave oscillator circuit, realize variable frequency by the capacity that changes the capacitor (C2) that output connects, the output of triangular wave oscillator circuit connects discharge circuit and forms square wave generation circuit.
5, microwave oven magnetic working power according to claim 1 and 2, it is characterized in that thermistor (RT) composition feedback circuit both can pick out from filtering high-frequency rectifier device output, also can behind diode rectification, pick out the other end ground connection of filament power supply coil from a power end of coil of filament.
6, microwave oven magnetic working power according to claim 1 is characterized in that industrial frequency rectifying filter (A) circuit adopts full-wave bridge rectifier element and electrolytic capacitor to constitute.
7, microwave oven magnetic working power according to claim 1 is characterized in that filtering high-frequency rectifier device (C) circuit is made up of rectifier diode and high-voltage capacitance.
8, microwave oven magnetic working power according to claim 1, it is characterized in that the pulse signal source that adjustable frequency square-wave generator (F) circuit is provided by the Switching Power Supply managing chip on the computer control board, connect photoelectricity isolating interface and current pulse width modulation device integrated circuit (UC3842) and constitute exciting signal source.
9, microwave oven magnetic working power according to claim 1 is characterized in that supply convertor (B) connects the load switch transformer by the high-power crystal switching tube and forms transistor switching circuit and constitute.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410024251 CN1707928A (en) | 2004-06-09 | 2004-06-09 | Microwave oven magnetron working electric power source |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410024251 CN1707928A (en) | 2004-06-09 | 2004-06-09 | Microwave oven magnetron working electric power source |
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| CN1707928A true CN1707928A (en) | 2005-12-14 |
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| CN 200410024251 Pending CN1707928A (en) | 2004-06-09 | 2004-06-09 | Microwave oven magnetron working electric power source |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497114A (en) * | 2011-11-29 | 2012-06-13 | 深圳麦格米特电气股份有限公司 | Frequency conversion microwave oven power supply circuit and control method thereof |
| CN106507523A (en) * | 2016-11-08 | 2017-03-15 | 烟台长青微波科技有限公司 | A kind of constant current mode microwave oven supply power |
| CN108282914A (en) * | 2018-03-21 | 2018-07-13 | 深圳戴普森新能源技术有限公司 | Microwave oven supply power circuit and micro-wave oven |
| CN112839398A (en) * | 2019-11-25 | 2021-05-25 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating device and dry burning detection method thereof |
-
2004
- 2004-06-09 CN CN 200410024251 patent/CN1707928A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497114A (en) * | 2011-11-29 | 2012-06-13 | 深圳麦格米特电气股份有限公司 | Frequency conversion microwave oven power supply circuit and control method thereof |
| CN102497114B (en) * | 2011-11-29 | 2014-06-25 | 深圳麦格米特电气股份有限公司 | Frequency conversion microwave oven power supply circuit and control method thereof |
| CN106507523A (en) * | 2016-11-08 | 2017-03-15 | 烟台长青微波科技有限公司 | A kind of constant current mode microwave oven supply power |
| CN108282914A (en) * | 2018-03-21 | 2018-07-13 | 深圳戴普森新能源技术有限公司 | Microwave oven supply power circuit and micro-wave oven |
| CN112839398A (en) * | 2019-11-25 | 2021-05-25 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating device and dry burning detection method thereof |
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