CN107147298A - A kind of microwave oven magnetic supply unit with pull-up active clamp branch road - Google Patents

A kind of microwave oven magnetic supply unit with pull-up active clamp branch road Download PDF

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Publication number
CN107147298A
CN107147298A CN201710405864.5A CN201710405864A CN107147298A CN 107147298 A CN107147298 A CN 107147298A CN 201710405864 A CN201710405864 A CN 201710405864A CN 107147298 A CN107147298 A CN 107147298A
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China
Prior art keywords
voltage
circuit
main switch
frequency
supply unit
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Granted
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CN201710405864.5A
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Chinese (zh)
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CN107147298B (en
Inventor
王春芳
李震
魏芝浩
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Qingdao University
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Qingdao University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/38—Means for preventing simultaneous conduction of switches
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
    • H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
    • H02M5/10—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers
    • H02M5/12—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers for conversion of voltage or current amplitude only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/10—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode arranged for operation in series, e.g. for multiplication of voltage
    • H02M7/103—Containing passive elements (capacitively coupled) which are ordered in cascade on one source
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • 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
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • 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
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Inverter Devices (AREA)

Abstract

The invention belongs to electroporation field, it is related to an a kind of microwave oven magnetic supply unit with pull-up active clamp branch road, in frequency-conversion microwave oven magnetron power source one pull-up active clamp branch road of increase in LC resonance single tube bipolarity inverter topologies, an auxiliary switch is included in the branch road, main switch is identical with the switching frequency of auxiliary switch, Sofe Switch control can be achieved, and reliability is improved without straight-through problem between two pipes；And in the case where keeping original circuit advantage, make switching tube is pressure-resistant to be reduced to original 2/3, switching tube can be used as using MOS transistor, switching frequency is up to more than 100kHz, simultaneously because auxiliary switch ON time is short, low in energy consumption, technical scheme is provided to reduce the volume and weight of power supply, reduction power supply cost.

Description

A kind of microwave oven magnetic supply unit with pull-up active clamp branch road
Technical field：
The invention belongs to electroporation field, it is related to a kind of microwave oven magnetic supply unit with active clamp circuit, Particularly a kind of microwave oven magnetic supply unit with pull-up active clamp branch road.
Background technology：
At present, household variable-frequency microwave oven magnetron power source circuit typically uses LLC resonance oscillation semi-bridges inverter topology or LC Resonance single tube bipolarity inverter topology, the former exists, and circuit structure is relative complex, and power supply cost is of a relatively high, on bridge arm Lower switching tube easily causes the problems such as leading directly to and burn out；Although the latter's circuit structure is simple, cost is low, efficiency high, can be achieved zero Voltage opens the advantages of being controlled with zero voltage turn-off, but there is also some shortcomings, when micro-wave oven input voltage is 220Vac/ During 50Hz alternating currents, switching tube bears high pressure up to more than 1200V to micro-wave oven in the process of running, causes switching tube to select Pressure-resistant higher isolated-gate field effect transistor (IGFET) (IGBT), and in order to Serial regulation magnetron power output, it is necessary to which IGBT is mono- The switching frequency of pipe does Frequency-variable Modulation between 20kHz to 40kHz, and after IGBT switching frequency is more than 25kHz, it is damaged Consumption can increase with the increase of switching frequency, so as to constrain the further raising of switching frequency, it is impossible to make supply unit Volume and cost are further reduced, and are unfavorable for the popularization and application of this novel microwave oven magnetron power supply.Therefore, one is designed Plant the new microwave oven magnetic supply unit with pull-up active clamp branch road has application and development value very much.
The content of the invention：
It is an object of the invention to overcome the shortcoming of prior art, in frequency-conversion microwave oven magnetron power source LC resonance single tubes Increase in bipolarity inverter topology and opened in a pull-up active clamp branch road, the branch road comprising an auxiliary switch, master Close pipe identical with the switching frequency of auxiliary switch, Sofe Switch control can be achieved, and without straight-through problem between two pipes, raising can By property；And in the case where keeping original circuit advantage, make switching tube is pressure-resistant to be reduced to original 2/3, metal can be used Oxide transistor (MOSFET) as switching tube, switching frequency up to more than 100kHz, while because auxiliary switch turn on when Between it is short, low in energy consumption, for reduce power supply volume and weight, reduction power supply cost provide technical scheme.
To achieve these goals, the microwave oven magnetic supply unit of the present invention with pull-up active clamp branch road Agent structure include rectifier bridge, L1C1Filter circuit, sample circuit, pull-up active clamp branch road, resonant capacitance, main switch, First diode, high frequency transformer, high frequency voltage doubling rectifier circuit, discharge resistance, magnetron and control circuit, the first diode is The anti-paralleled diode of main switch, single phase industrial frequence alternating current sequentially passes through rectifier bridge, L1C1Direct current is converted into after filter circuit Electricity, main switch, the first diode and pull-up active clamp branch road are by DC inverter into high-frequency alternating current, this high-frequency alternating current The primary side winding two ends of high frequency transformer are applied to, after transformer boost, the vice-side winding two ends of high frequency transformer produce height Frequency High Level AC Voltage, this high-frequency and high-voltage alternating current is powered after high frequency voltage doubling rectifier circuit for magnetron；High frequency transformer secondary The alternating current direct that produces of Filament Winding be connected in magnetron heater and power；Single phase industrial frequence alternating current is carried out rectification, L by rectifier bridge1C1 Filter circuit is made up of filter inductance and filter capacitor electrical connection, for power frequency filtering；Sample circuit is by the first sampling resistor, Two sampling resistor summation current transformers electrical connection composition, sample circuit is together with the input voltage and input current detection circuit for controlling circuit For detecting input voltage and input current；Active clamp branch route clamp capacitor, auxiliary switch and the second diode are pulled up according to electricity Learn principle to be electrically connected to form, the second diode is the anti-paralleled diode of auxiliary switch, auxiliary switch source electrode and main switch Pipe drain electrode is connected, and clamp capacitor one end is connected with auxiliary switch drain electrode, and the other end is connected with the positive pole of filter capacitor；Work as power supply Device accesses 220VacAlternating current and control on circuit electric, after main switch shut-off, main switch drain-source both end voltage gradually rises Height, when this voltage rises to filter capacitor with clamp capacitor voltage sum, the voltage at main switch drain-source two ends is clamped at Filter capacitor and clamp capacitor two ends, reduction main switch is pressure-resistant；Resonant capacitance is in parallel with the primary side winding of high frequency transformer, The opening of main switch, turn off under change, resonance occurs for the inductance of resonant capacitance and primary side winding, realizes high-frequency inversion；High frequency Transformer by primary side winding, vice-side winding, Filament Winding and with air gap magnetic core electrical connection constitute, the former and deputy side of high frequency transformer The coefficient of coup is 0.5-0.95, vice-side winding access high frequency voltage doubling rectifier circuit, and the filament of Filament Winding and magnetron is connected to Magnetron provides Alternating Current Power Supply, and electrical isolation is realized while high frequency transformer is by primary side high-frequency ac electric boost；High frequency voltage-multiplying Rectification circuit is by the first kenotron, the second kenotron, the first filter capacitor and the second filter capacitor electricity Connection is constituted, and high frequency voltage doubling rectifier circuit will be after the vice-side winding institute output voltage progress voltage multiplying rectifier filtering of high frequency transformer Magnetron is powered；Discharge resistance is that the first filter capacitor and the second filter capacitor provide discharge loop；Magnetron is micro- for producing Ripple；Circuit is controlled to detect that circuit, first voltage detect that circuit, second voltage detect circuit, micro-wave oven work(by input voltage and input current Energy menu or artificial setting signal, single-chip microcomputer, drive circuit, accessory power supply are electrically connected to form, input voltage and input current detection circuit For detecting input voltage, electric current, single-chip microcomputer enters line frequency according to detection data and adjusted, so as to change output voltage, realizes permanent Power Control；The voltage at first voltage detection electric circuit inspection clamp capacitor two ends, when the voltage for detecting clamp capacitor two ends increases The control signal of auxiliary switch is changed into high level by added-time, single-chip microcomputer, and auxiliary switch realizes that no-voltage is open-minded, when clamper electricity When holding the voltage increase at two ends, primary side winding is charged by the second diode for clamp capacitor, and the second diode current flow, auxiliary is opened The voltage for closing pipe drain-source two ends is zero；The voltage at second voltage detection electric circuit inspection main switch drain-source two ends；Micro-wave oven function Menu or artificial setting signal provide the combination of microwave firepower and its respective action time for single-chip microcomputer；Drive circuit is in single-chip microcomputer control The break-make of the lower driving main switch of system and auxiliary switch；Accessory power supply is single-chip microcomputer and drive circuitry.
The present invention realize with pull-up active clamp branch road microwave oven magnetic supply unit control process include with Lower step：
(1) it is electric on circuit, first SCM program initialization, and receive by micro-wave oven function menu or artificial setting signal biography The corresponding microwave firepower combination come and its respective action time；Then judge whether to press job key, if not pressing job key Then into holding state, simultaneously the moment detects whether to press job key, enters PWM (pulse width modulation) just if job key is pressed Beginningization；After PWM initialization, single-chip microcomputer is according to corresponding to being combined microwave firepower and its respective action time sets each microwave firepower Switching frequency and pwm signal, and the corresponding switching frequency of first microwave firepower and PWM first in the combination of output microwave firepower Signal, now supply unit start-up operation；
(2) when supply unit works, power output is adjusted by power limitation control, first according to output microwave firepower Set corresponding power；Then detect that the voltage detected, current signal are sent to monolithic by circuit by input voltage and input current Machine, single-chip microcomputer is by calculating input voltage, the product of electric current draws input power；Finally by compare input power with setting work( Rate adjusts the switching frequency of supply unit, if input power is more than setting power, single-chip microcomputer by increase switching frequency come Reduce power output, if input power is less than setting power, single-chip microcomputer increases power output by reducing switching frequency, real The power limitation control of existing supply unit；Meanwhile, supply unit in the course of the work, makes main switch by the control and regulation of single-chip microcomputer Pipe and auxiliary switch realize Sofe Switch control, and first voltage detects electric circuit inspection to the voltage increase at clamp capacitor two ends When, the control signal of auxiliary switch is changed into high level by single-chip microcomputer, and auxiliary switch realizes that no-voltage is open-minded；Opened in current master Close before the arrival of pipe drive signal rising edge, second voltage detects the magnitude of voltage at electric circuit inspection main switch drain-source two ends, if main The voltage at switching tube drain-source two ends is not 0, that is, is not carried out that no-voltage is open-minded, then single-chip microcomputer reduces the dutycycle of main switch, If the voltage at main switch drain-source two ends is 0, that is, realize that no-voltage is open-minded, then the dutycycle of main switch is constant；
(3) single-chip microcomputer moment in the supply unit course of work judges whether correspondence firepower action time terminates, if not tying Shu Ze continues to current switch frequency and pwm signal；Last microwave firepower is determined whether if terminating, if not then Microwave firepower+1, then exports the corresponding switching frequency of next microwave firepower and pwm signal, and repeat the above steps；If PWM locking signals are then exported, block PWM is exported, and then supply unit is stopped；When program is run, the moment detects whether End key is pressed, if the not normal operation of reprogramming without if, PWM locking signals are directly entered if having, stops power supply dress Work is put, the control of microwave oven magnetic supply unit is completed.
Compared with prior art, the high frequency transformer of supply unit can realize bidirectional excitation to the present invention so that power supply is filled Larger power can be exported by putting；Main switch and auxiliary switch have identical switching frequency, in the absence of straight-through problem, all Sofe Switch can be realized, and auxiliary switch only turns on a bit of time in each switch periods, conduction loss is greatly reduced；Transformation The high frequency voltage doubling rectifier circuit of device secondary cascade causes the asymmetrical voltage that transformer secondary winding is exported to be utilized effectively, and makes The whole efficiency of supply unit is further improved；The inductance of transformer primary side resonant capacitance and transformer primary side winding in parallel enters Row resonance causes there is higher voltage gain, in the case where transformer turn ratio is certain, energy between supply unit input/output Output voltage amplitude is improved by pulse frequency modulated moment, frequency-conversion microwave oven magnetron is quickly realized startup；Pull-up is active The clamping action of clamper branch road makes the pressure-resistant reduction by 1/3 of main switch, main switch and auxiliary switch is used MOSFET As switch, its switching frequency further reduces the volume and weight of supply unit up to more than 100kHz, reduces supply unit Cost；Its circuit structure is simple, and cost is low, and reliability is high, efficiency high, can be adjusted by pulse width modulation+pulse frequency Make the control method being combined and precisely change output voltage and power in a wide range of and small range, application prospect is extensive.
Brief description of the drawings：
Fig. 1 is the main circuit structure of the microwave oven magnetic supply unit of the present invention with pull-up active clamp branch road Principle schematic.
Fig. 2 is the work that the present invention realizes the microwave oven magnetic supply unit control with pull-up active clamp branch road Skill FB(flow block).
Fig. 3 is the work wave of the microwave oven magnetic supply unit of the present invention with pull-up active clamp branch road Figure, wherein Ugs1For main switch Q1Driving voltage, Ugs2For auxiliary switch Q2Driving voltage, Uds1For main switch Q1Leakage The voltage at source two ends, Uds2For auxiliary switch Q2The voltage at drain-source two ends, UC3For resonant capacitance C3The voltage at two ends, IL2For original Side winding L2Electric current, UC2For clamp capacitor C2The voltage at two ends.
Embodiment：
Technical scheme is described in more detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment：
The agent structure of microwave oven magnetic supply unit with pull-up active clamp branch road described in the present embodiment includes Rectifier bridge 1, L1C1Filter circuit 2, sample circuit 3, pull-up active clamp branch road 4, resonant capacitance C3, main switch Q1, the one or two Pole pipe VD1, high frequency transformer 5, high frequency voltage doubling rectifier circuit 6, discharge resistance R3, magnetron 7 and control circuit 8, the first diode VD1For main switch Q1Anti-paralleled diode, single phase industrial frequence alternating current sequentially passes through rectifier bridge 1, L1C1Turn after filter circuit 2 Change direct current, main switch Q into1, the first diode VD1With pull-up active clamp branch road 4 by DC inverter into high-frequency ac Electricity, this high-frequency alternating current is applied to the primary side winding L of high frequency transformer 52Two ends, after transformer boost, the secondary of high frequency transformer 5 Winding L3Two ends produce high-frequency and high-voltage alternating current, and this high-frequency and high-voltage alternating current is supplied after high frequency voltage doubling rectifier circuit 6 for magnetron 7 Electricity；The Filament Winding L of the secondary of high frequency transformer 54The alternating current direct of generation is connected in magnetron heater and powered；Rectifier bridge 1 will be single-phase Industrial-frequency alternating current carries out rectification, L1C1Filter circuit 2 is by filter inductance L1With filter capacitor C1Electrical connection composition, for power frequency filter Ripple；Sample circuit 3 is by the first sampling resistor R1, the second sampling resistor R2Summation current transformer CT1Electrical connection composition, sample circuit 3 It is used to detect input voltage and input current together with the input voltage and input current detection circuit 81 for controlling circuit 8；Pull up active clamp branch road 4 By clamp capacitor C2, auxiliary switch Q2With the second diode VD2It is electrically connected to form according to electrical principles, the second diode VD2For Auxiliary switch Q2Anti-paralleled diode, auxiliary switch Q2Source electrode and main switch Q1Drain electrode is connected, clamp capacitor C2One end With auxiliary switch Q2Drain electrode is connected, the other end and filter capacitor C1Positive pole be connected；When supply unit accesses 220VacAlternating current And control electric on circuit, main switch Q1After shut-off, main switch Q1Drain-source both end voltage gradually rises, when this voltage rises To filter capacitor C1With clamp capacitor C2During voltage sum, main switch Q1The voltage at drain-source two ends is clamped at filter capacitor C1 With clamp capacitor C2Two ends, reduction main switch Q1It is pressure-resistant；Resonant capacitance C3With the primary side winding L of high frequency transformer 52Parallel connection, Main switch Q1Open, turn off change under, resonant capacitance C3With primary side winding L2Inductance occur resonance, realize high-frequency inversion； High frequency transformer 5 is by primary side winding L2, vice-side winding L3, Filament Winding L4With band air gap magnetic core T electrical connection compositions, high frequency transformation The former and deputy side coefficient of coup of device 5 is 0.5-0.95, vice-side winding L3Access high frequency voltage doubling rectifier circuit 6, Filament Winding L4With magnetic The filament of keyholed back plate 7 is connected to magnetron 7 and provides Alternating Current Power Supply, and high frequency transformer 5 will be real while primary side high-frequency ac electric boost Existing electrical isolation；High frequency voltage doubling rectifier circuit 6 is by the first kenotron VD3, the second kenotron VD4, first Filter capacitor C4With the second filter capacitor C5Electrical connection composition, high frequency voltage doubling rectifier circuit 6 is by the vice-side winding of high frequency transformer 5 L3Institute's output voltage carries out being that magnetron 7 is powered after voltage multiplying rectifier filtering；Discharge resistance R3For the first filter capacitor C4With the second filter Ripple electric capacity C5Discharge loop is provided；Magnetron 7 is used to produce microwave；Circuit 8 is controlled to detect circuit 81, the by input voltage and input current One voltage detecting circuit 82, second voltage detection circuit 83, micro-wave oven function menu or artificial setting signal 84, single-chip microcomputer 85, Drive circuit 86, accessory power supply 87 are electrically connected to form, and input voltage and input current detection circuit 81 is used to detect input voltage, electric current, Single-chip microcomputer 85 enters line frequency adjustment according to detection data, so as to change output voltage, realizes power limitation control；First voltage is detected The detection clamp capacitor of circuit 82 C2The voltage at two ends, when detecting clamp capacitor C2During the voltage increase at two ends, single-chip microcomputer 85 will be auxiliary Help switching tube Q2Control signal be changed into high level, auxiliary switch Q2Realize that no-voltage is open-minded, as clamp capacitor C2The electricity at two ends During pressure increase, primary side winding L2Pass through the second diode VD2For clamp capacitor C2Charging, the second diode VD2Conducting, auxiliary is opened Close pipe Q2The voltage at drain-source two ends is zero；The second voltage detection detection main switch of circuit 83 Q1The voltage at drain-source two ends；Micro-wave oven Function menu or artificial setting signal 84 are that single-chip microcomputer 85 provides the combination of microwave firepower and its respective action time；Drive circuit 86 The driving main switch Q under the control of single-chip microcomputer 851With auxiliary switch Q2Break-make；Accessory power supply 87 is single-chip microcomputer 85 and driving Circuit 86 is powered.
The present embodiment realizes that the process of the microwave oven magnetic supply unit control with pull-up active clamp branch road includes Following steps：
(1) it is electric on circuit, first SCM program initialization, and receive by micro-wave oven function menu or artificial setting signal 84 The corresponding microwave firepower combination transmitted and its respective action time；Then judge whether to press job key, if not pressing work Then into holding state, simultaneously the moment is detected whether to press job key key, and PWM (pulse width modulation) is entered if job key is pressed Initialization；After PWM initialization, single-chip microcomputer 85 is combined according to microwave firepower and its respective action time sets each microwave firepower institute Corresponding switching frequency and pwm signal, and the corresponding switching frequency of first microwave firepower first in the combination of output microwave firepower And pwm signal, now supply unit start-up operation；
(2) when supply unit works, power output is adjusted by power limitation control, first according to output microwave firepower Set corresponding power；Then detect that the voltage detected, current signal are sent to list by circuit 81 by input voltage and input current Piece machine 85, single-chip microcomputer 85 is by calculating input voltage, the product of electric current draws input power；Finally by compare input power with Set power to adjust the switching frequency of supply unit, if input power is more than setting power, single-chip microcomputer 85 is opened by increase Close frequency to reduce power output, if input power is less than setting power, single-chip microcomputer 85 increases by reducing switching frequency Power output, realizes the power limitation control of supply unit；Meanwhile, supply unit in the course of the work, passes through the control of single-chip microcomputer 85 Regulation processed makes main switch Q1With auxiliary switch Q2Sofe Switch control is realized, first voltage detection circuit 82 detects clamper Electric capacity C2During the voltage increase at two ends, single-chip microcomputer 85 is by auxiliary switch Q2Control signal be changed into high level, auxiliary switch Q2 Realize that no-voltage is open-minded；In current main switch Q1Before drive signal rising edge arrives, second voltage detection circuit 83 is detected Main switch Q1The magnitude of voltage at drain-source two ends, if main switch Q1The voltage at drain-source two ends is not 0, that is, is not carried out no-voltage and opens Logical, then single-chip microcomputer 85 reduces main switch Q1Dutycycle, if main switch Q1The voltage at drain-source two ends is 0, that is, realizes no-voltage It is open-minded, then main switch Q1Dutycycle it is constant；
(3) moment in the supply unit course of work of single-chip microcomputer 85 judges whether correspondence firepower action time terminates, if not having End then continues to current switch frequency and pwm signal；Determine whether last microwave firepower if terminating, if not Then microwave firepower+1, then exports the corresponding switching frequency of next microwave firepower and pwm signal, and repeat the above steps；If It is then output PWM locking signals, block PWM outputs, then supply unit is stopped；When program is run, moment detection is It is no to press end key, if the not normal operation of reprogramming without if, PWM locking signals are directly entered if having, stop power supply Device works, and completes the control of microwave oven magnetic supply unit.
The working waveform figure bag of microwave oven magnetic supply unit with pull-up active clamp branch road described in the present embodiment Include with the next stage：
t0-t1Period：In t0Moment, main switch Q1Driving voltage Ugs1It is changed into high level, now primary side winding L2Electricity It is negative to flow, main switch Q1It is not turned on, primary side winding L2Pass through the first diode VD1With filter capacitor C1Afterflow, main switch Q1 It is pressure-resistant be 0, to t1Moment, primary side winding L2Electric current be changed into 0, main switch Q1Conducting, realizes main switch Q1No-voltage is opened It is logical；
t1-t2Period：Input voltage is primary side winding L2Charging, primary side winding L2Electric current gradually increase, to t2It is moment, main Switching tube Q1Driving voltage Ugs1It is changed into low level, main switch Q1Shut-off；
t2-t3Period：Resonant capacitance C3For primary side winding L2Charging, primary side winding L2Electric current continue increase, to t3Moment, Resonant capacitance C3Voltage be reduced to 0, primary side winding L2Electric current increase to maximum；
t3-t4Period：Primary side winding L2It is reversed resonant capacitance C3Charging, resonant capacitance C3Voltage reversal increase, resonance Electric capacity C3Voltage be less than clamp capacitor C2Voltage, the second diode VD2Reversely cut-off, to t4Moment, resonant capacitance C3Electricity Pressure is more than clamp capacitor C2Voltage, the second diode VD2Conducting；
t4-t5Period：Primary side winding L2It is simultaneously clamp capacitor C2With resonant capacitance C3Charging, clamp capacitor C2Voltage by It is cumulative big, to t5Moment, auxiliary switch Q2Driving voltage Ugs2It is changed into high level, but primary side winding L2Electric current still for just, Auxiliary switch Q2It is not turned on；
t5-t6Period：Primary side winding L2Continue as clamp capacitor C2With resonant capacitance C3Charging, the second diode VD2Conducting, Auxiliary switch Q2The voltage at two ends is 0, to t6Moment, primary side winding L2Electric current drop to 0, clamp capacitor C2Voltage increase Maximum is added to, while resonant capacitance C3Voltage reversal increase to maximum, resonant capacitance C3Start as primary side winding L2Reversely fill Electricity, now resonant capacitance C3Voltage is less than clamp capacitor C2Voltage, auxiliary switch Q2Conducting, realizes auxiliary switch Q2Zero Voltage is open-minded；
t6-t7Period：Clamp capacitor C2For primary side winding L2Reverse charging, to t7Moment, auxiliary switch Q2Driving electricity Press Ugs2It is changed into low level, auxiliary switch Q2Shut-off, clamp capacitor C2Stop as primary side winding L2Charging；
t7-t8Period：Resonant capacitance C3Voltage reduction, primary side winding L2Electric current reduce, to t8Moment, resonant capacitance C3 Voltage be changed into 0；
t8-t9Period：Primary side winding L2For resonant capacitance C3Reverse charging, resonant capacitance C3Voltage gradually increase, to t9 Moment, resonant capacitance C3Voltage increase to and filter capacitor C1Voltage it is equal；
t9-t10Period：Primary side winding L2Pass through the first diode VD1With filter capacitor C1Afterflow, to t10Moment, main switch Pipe Q1Driving voltage Ugs1It is changed into high level, now primary side winding L2Electric current be negative, main switch Q1It is not turned on.

Claims (2)

1. a kind of microwave oven magnetic supply unit with pull-up active clamp branch road, it is characterised in that：In frequency-conversion microwave oven Magnetron power source one pull-up active clamp branch road of increase in LC resonance single tube bipolarity inverter topologies, concrete structure bag Include rectifier bridge, L1C1Filter circuit, sample circuit, pull-up active clamp branch road, resonant capacitance, main switch, the first diode, High frequency transformer, high frequency voltage doubling rectifier circuit, discharge resistance, magnetron and control circuit, the first diode is main switch Anti-paralleled diode, single phase industrial frequence alternating current sequentially passes through rectifier bridge, L1C1It is converted into direct current after filter circuit, main switch, First diode with pull-up active clamp branch road by DC inverter into high-frequency alternating current, this high-frequency alternating current be applied to high frequency change The primary side winding two ends of depressor, after transformer boost, the vice-side winding two ends of high frequency transformer produce high-frequency and high-voltage alternating current, This high-frequency and high-voltage alternating current is powered after high frequency voltage doubling rectifier circuit for magnetron；The Filament Winding of high frequency transformer secondary is produced Alternating current direct be connected in magnetron heater and power；Single phase industrial frequence alternating current is carried out rectification, L by rectifier bridge1C1Filter circuit is by filtering Inductance and filter capacitor electrical connection composition, for power frequency filtering；Sample circuit is by the first sampling resistor, the second sampling resistor and electricity Current transformer electrical connection composition, sample circuit is used to detect input electricity together with the input voltage and input current detection circuit for controlling circuit Current voltage；Pull up active clamp branch route clamp capacitor, auxiliary switch and the second diode and electrically connect structure according to electrical principles Into the second diode is the anti-paralleled diode of auxiliary switch, and auxiliary switch source electrode is connected with main switch drain electrode, clamper Electric capacity one end is connected with auxiliary switch drain electrode, and the other end is connected with the positive pole of filter capacitor；When supply unit accesses 220VacHand over Stream is electric and controls electricity on circuit, and after main switch shut-off, main switch drain-source both end voltage gradually rises, when this voltage rises During to filter capacitor and clamp capacitor voltage sum, the voltage at main switch drain-source two ends is clamped at filter capacitor and clamper electricity Hold two ends, reduction main switch is pressure-resistant；Resonant capacitance is in parallel with the primary side winding of high frequency transformer, the opening of main switch, Under shut-off change, resonance occurs for the inductance of resonant capacitance and primary side winding, realizes high-frequency inversion；High frequency transformer by primary side around Group, vice-side winding, Filament Winding and being electrically connected with air gap magnetic core are constituted, and the former and deputy side coefficient of coup of high frequency transformer is 0.5- 0.95, vice-side winding access high frequency voltage doubling rectifier circuit, Filament Winding is connected to magnetron offer with the filament of magnetron and exchanged Power supply, electrical isolation is realized while high frequency transformer is by primary side high-frequency ac electric boost；High frequency voltage doubling rectifier circuit is by first Kenotron, the second kenotron, the first filter capacitor and the second filter capacitor electrical connection composition, high frequency times Voltage rectifier is powered after the vice-side winding institute output voltage of high frequency transformer is carried out into voltage multiplying rectifier filtering for magnetron；Electric discharge Resistance is that the first filter capacitor and the second filter capacitor provide discharge loop；Magnetron is used to produce microwave；Circuit is controlled by defeated Enter voltage and current detection circuit, first voltage detection circuit, second voltage detection circuit, micro-wave oven function menu or artificial setting Signal, single-chip microcomputer, drive circuit, accessory power supply are electrically connected to form, input voltage and input current detection circuit be used for detect input voltage, Electric current, single-chip microcomputer enters line frequency according to detection data and adjusted, so as to change output voltage, realizes power limitation control；First voltage The voltage at electric circuit inspection clamp capacitor two ends is detected, when detecting the voltage increase at clamp capacitor two ends, single-chip microcomputer will be aided in The control signal of switching tube is changed into high level, and auxiliary switch realizes that no-voltage is open-minded, when the voltage increase at clamp capacitor two ends When, primary side winding is charged by the second diode for clamp capacitor, the second diode current flow, the electricity at auxiliary switch drain-source two ends Pressure is zero；The voltage at second voltage detection electric circuit inspection main switch drain-source two ends；Micro-wave oven function menu or artificial setting letter Number for single-chip microcomputer provide microwave firepower combination and its respective action time；Drive circuit drives main switch under single-chip microcomputer control With the break-make of auxiliary switch；Accessory power supply is single-chip microcomputer and drive circuitry.
2. the microwave oven magnetic supply unit according to claim 1 with pull-up active clamp branch road, it is characterised in that： The process for realizing the control of microwave oven magnetic supply unit using the author comprises the following steps：
(1) it is electric on circuit, first SCM program initialization, and receive what is transmitted by micro-wave oven function menu or artificial setting signal The combination of correspondence microwave firepower and its respective action time；Then judge whether to press job key, enter if job key is not pressed Enter holding state and the moment detects whether to press job key, PWM is entered if job key is pressed and is initialized；It is single after PWM initialization Switching frequency and PWM letter of the piece machine according to corresponding to being combined microwave firepower and its respective action time sets each microwave firepower Number, and the corresponding switching frequency of first microwave firepower and pwm signal first in the combination of output microwave firepower, now supply unit Start working；
(2) when supply unit works, power output is adjusted by power limitation control, first according to output microwave firepower setting Corresponding power；Then detect that the voltage detected, current signal are sent to single-chip microcomputer by circuit by input voltage and input current, it is single Piece machine is by calculating input voltage, the product of electric current draws input power；Finally by compare input power with setting power The switching frequency of supply unit is adjusted, if input power is more than setting power, single-chip microcomputer reduces by increasing switching frequency Power output, if input power is less than setting power, single-chip microcomputer increases power output by reducing switching frequency, realizes electricity The power limitation control of source device；Meanwhile, supply unit in the course of the work, by the control and regulation of single-chip microcomputer make main switch and Auxiliary switch realizes Sofe Switch control, single during the voltage increase of first voltage detection electric circuit inspection to clamp capacitor two ends The control signal of auxiliary switch is changed into high level by piece machine, and auxiliary switch realizes that no-voltage is open-minded；In current main switch Before drive signal rising edge arrives, the magnitude of voltage at second voltage detection electric circuit inspection main switch drain-source two ends, if main switch The voltage at pipe drain-source two ends is not 0, that is, is not carried out that no-voltage is open-minded, then single-chip microcomputer reduces the dutycycle of main switch, if main The voltage at switching tube drain-source two ends is 0, that is, realizes that no-voltage is open-minded, then the dutycycle of main switch is constant；
(3) single-chip microcomputer moment in the supply unit course of work judges whether correspondence firepower action time terminates, if not terminating Continue to current switch frequency and pwm signal；Last microwave firepower is determined whether if terminating, if not then microwave Firepower+1, then exports the corresponding switching frequency of next microwave firepower and pwm signal, and repeat the above steps；If then defeated Go out PWM locking signals, block PWM is exported, and then supply unit is stopped；When program is run, the moment detects whether to press End key, if the not normal operation of reprogramming without if, is directly entered PWM locking signals if having, stops supply unit work Make, complete the control of microwave oven magnetic supply unit.
CN201710405864.5A 2017-05-31 2017-05-31 A kind of microwave oven magnetic power supply device with pull-up active clamp branch Active CN107147298B (en)

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CN110025311A (en) * 2019-02-22 2019-07-19 四川华微康医疗科技有限公司 A kind of Miniaturized portable microwave source for microwave thermoacoustic imaging
CN111628654A (en) * 2019-02-28 2020-09-04 东南大学 Switching power supply circuit
WO2021138820A1 (en) * 2020-01-07 2021-07-15 Oppo广东移动通信有限公司 Charger and control method
CN113381615A (en) * 2020-07-14 2021-09-10 成都芯源系统有限公司 Energy recovery circuit and method for isolating voltage converter

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Publication number Priority date Publication date Assignee Title
CN110025311A (en) * 2019-02-22 2019-07-19 四川华微康医疗科技有限公司 A kind of Miniaturized portable microwave source for microwave thermoacoustic imaging
CN111628654A (en) * 2019-02-28 2020-09-04 东南大学 Switching power supply circuit
CN111628654B (en) * 2019-02-28 2023-11-24 东南大学 Switching power supply circuit
WO2021138820A1 (en) * 2020-01-07 2021-07-15 Oppo广东移动通信有限公司 Charger and control method
CN113381615A (en) * 2020-07-14 2021-09-10 成都芯源系统有限公司 Energy recovery circuit and method for isolating voltage converter

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