CN202906748U - Medium-frequency power supply of double-resonance thyristor - Google Patents
Medium-frequency power supply of double-resonance thyristor Download PDFInfo
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- CN202906748U CN202906748U CN2012205611972U CN201220561197U CN202906748U CN 202906748 U CN202906748 U CN 202906748U CN 2012205611972 U CN2012205611972 U CN 2012205611972U CN 201220561197 U CN201220561197 U CN 201220561197U CN 202906748 U CN202906748 U CN 202906748U
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- 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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Abstract
Provided is a medium-frequency power supply of a double-resonance thyristor, belonging to the field of power. The medium-frequency power supply comprises a main power circuit breaker, a three-phase fully-controlled rectifier, a middle filter circuit, a single-phase inverter power supply and an induction heating load loop. The medium-frequency power supply is characterized in that an inverter input end resonant loop is arranged between the middle filter circuit and the single-phase inverter power supply, an input end of the inverter input end resonant loop is correspondingly connected with an output end of the middle filter circuit, an output end of the inverter input end resonant loop is correspondingly connected with an input end of the single-phase inverter power supply, and the inverter input end resonant loop is an LC parallel resonant circuit. As a medium-frequency current waveform obtained by the load loop is a periodic sine wave, current and voltage waveforms obtained from two ends of a load are periodic sine waves, the switching loss of an inverter device can be effectively reduced, and the reliability and efficiency of a middle-frequency power supply device can be improved. The added LC resonant loop circuit will not damage an original circuit, is easy to control and can be conducive to the implementation and promotion of the technical scheme.
Description
Technical field
The utility model belongs to field of power supplies, relates in particular to a kind of thyristor electronic power rectification device for load coil.
Background technology
In industrial power equipment, usually form thyristor intermediate frequency power supply by electronic power rectifier, intermediate circuit, inverter, parallel resonance formula load coil and starting circuit.
And double resonance formula thyristor intermediate frequency power supply then forms intermediate frequency power supply by rectifier, intermediate circuit, quasi-resonance circuit, inverter, parallel resonance formula load coil and starting circuit.Because after increasing the quasi-resonance circuit, the intermediate frequency power supply operating characteristic improves, equipment Reliability and power-efficient also are improved.
Usually thyristor parallel resonance intermediate frequency power supply belongs to the constant current source power supply working method, namely allow alternating current obtain direct current by rectifier, the large reactor of connecting between rectifier and the inverter again comes the electric current of guarantee the supply inverter relatively stable, then can see constant-current source as.
The characteristic of this class power supply is that the load current waveform that load coil (being load) two ends obtain is the square wave that changes in the cycle, and load voltage then is sinusoidal wave (referring to shown in Figure 1), so be referred to as again the current source system.
Because load current is square wave, then the rate of change of electric current is just very large, causes the technical parameter of inverter element is required just height, and the reliability of system depends on also to a great extent whether the performance of inverter element is stable.
The utility model content
Technical problem to be solved in the utility model provides a kind of double resonance formula thyristor intermediate frequency power supply, its inverter input terminal in conventional intermediate frequency power supply system has increased an inductance capacitor resonant tank, the electric current of intermediate frequency waveform that load circuit obtains is the sine wave that changes in the cycle, so that the current waveform and the voltage waveform that obtain at load coil (being load) two ends all are periodically variable sine waves, thereby effectively reduce current changing rate, also reduced the harsh requirement to the inverter technology parameter, and can effectively alleviate contrary devices switch loss, improve intermediate frequency power supply device reliability and efficient.
The technical solution of the utility model is: a kind of double resonance formula thyristor intermediate frequency power supply is provided, comprise the main power source circuit breaker, three-phase fully-controlled rectifier, median filter circuit, Single-Phase Inverter Source and the induction heating load circuit that connect successively, it is characterized in that: between described median filter circuit and Single-Phase Inverter Source, the inverter input resonant tank is set; The corresponding connection of output of the input of described inverter input resonant tank and median filter circuit; The connection corresponding to the input of Single-Phase Inverter Source of the output of described inverter input resonant tank.
Wherein, described inverter input resonant tank series connection is arranged between median filter circuit and the Single-Phase Inverter Source.
Further, described inverter input resonant tank is the LC antiresonant circuit.
Concrete, described LC antiresonant circuit is made of the second resonant capacitance and the second vibration inductance, and the two ends of its described the second resonant capacitance are respectively with the corresponding connection of positive and negative output of median filter circuit; One end of described the second vibration inductance is connected with the positive output end of median filter circuit and the positive terminal of resonant capacitance, and the other end of described the second vibration inductance is with the corresponding connection of positive input terminal of Single-Phase Inverter Source.
Further, described LC antiresonant circuit is made of the second resonant capacitance, the 3rd resonant capacitance and the second vibration inductance, wherein, the anodal in parallel rear of described second, third resonant capacitance is connected with the positive output end of median filter circuit, is connected with the negative output terminal of median filter circuit and the negative input end of Single-Phase Inverter Source after the negative pole parallel connection of described second, third resonant capacitance; The output of one end and the median filter circuit of described the second vibration inductance be connected the positive pole of resonant capacitance and be connected, described second other end that vibrates inductance is connected with the positive input terminal of Single-Phase Inverter Source.
Compared with the prior art, the utility model has the advantages that:
1. adopt the double-resonant circuit structure, newly increased the 2nd a LC resonant tank at inverter input terminal, the electric current of intermediate frequency waveform that load circuit obtains is the sine wave that changes in the cycle, power device of inverter loss that switch is hit can effectively be reduced, and the inversion device can significantly reduce the requirement of current changing rate, and the efficient of whole supply unit is improved;
2. because the current changing rate at load two ends is effectively reduced, can greatly simplify the protective circuit of power device, can effectively alleviate contrary devices switch loss, improve the reliability of whole supply unit;
3. the LC resonant tank circuit that increases is simple in structure, can not damage original circuit, is convenient to realize, is easy to control, helps enforcement and the popularization of the technical program.
Description of drawings
Fig. 1 is the load waveform schematic diagram of conventional thyristor intermediate frequency power supply;
Fig. 2 is functional circuit module structural representation of the present utility model;
Fig. 3 is the line map of the utility model embodiment major loop;
Fig. 4 is load waveform schematic diagram of the present utility model.
1 is the resonant capacitor electric current of conventional intermediate frequency power supply among the figure, 1 ' be resonant capacitor electric current of the present utility model, 2 is the induction coil electric current of conventional intermediate frequency power supply, 2 ' be induction coil electric current of the present utility model, 3 is the load voltage of conventional intermediate frequency power supply, 3 ' be load voltage of the present utility model, 4 is the load current of conventional intermediate frequency power supply, 4 ' be load current of the present utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model is described further.
At present, the main circuit structure of external thyristor type parallel resonance intermediate frequency power supply is usually by rectifier, median filter circuit, inverter (the thyristor device is take modular structure as main etc. multiple), induction heating load circuit (structural design is complicated), starting circuit (being the impacting type start mode) and control circuit (digital circuit application is also arranged for main, mould-number circuit) formation.
And the main circuit structure of domestic thyristor type parallel resonance intermediate frequency power supply is usually by rectifier, intermediate circuit, inverter when large capacity (monomer thyristor device is in the majority, series parallel structure), induction heating load circuit (in most cases structure is multiple), starting circuit (zero-pressure starting and compound start mode are in the majority) and control circuit (digital circuit is less, and mould-number circuit is more).
Existing conventional thyristor parallel resonance intermediate frequency power supply, belong to the constant current source power supply working method, namely allow alternating current obtain direct current by rectifier, the large reactor of between rectifier and inverter, connecting again, come the electric current of guarantee the supply inverter relatively stable, then can be referred to as constant-current source.
Among Fig. 1,1 is condenser current, and 2 is the induction coil electric current, and 3 is load voltage, and 4 is load current.
The characteristic of this class normal power supplies is, the current waveform 4 that load coil (being load) two ends obtain is the square waves that change in the cycle, and voltage 3 then be sine wave, so be referred to as again the current source system.
Because its load current is the square wave structure, the rate of change of electric current is just very large, causes the requirement of inverter element just highly, and the stable performance that the reliability of system also just depends on the inversion components and parts to a great extent whether.
Among Fig. 2, double resonance formula thyristor intermediate frequency power supply of the present utility model, comprise the main power source circuit breaker, three-phase fully-controlled rectifier, median filter circuit, Single-Phase Inverter Source and the induction heating load circuit that connect successively, it is characterized in that between median filter circuit and Single-Phase Inverter Source, being provided with the inverter input resonant tank; The corresponding connection of output of the input of its inverter input resonant tank and median filter circuit, the connection corresponding to the input of Single-Phase Inverter Source of the output of inverter input resonant tank.
Wherein, the series connection of inverter input resonant tank is arranged between median filter circuit and the Single-Phase Inverter Source.
Concrete, its inverter input resonant tank is the LC antiresonant circuit.
Further, its LC antiresonant circuit is made of the second resonant capacitance and the second vibration inductance, and the two ends of its second resonant capacitance are respectively with the corresponding connection of positive and negative output of median filter circuit; One end of its second vibration inductance is connected with the positive output end of median filter circuit and the positive terminal of resonant capacitance, and the other end of the second vibration inductance is with the corresponding connection of positive input terminal of Single-Phase Inverter Source.
Among Fig. 3, provided the major loop line map of the utility model double resonance formula thyristor intermediate frequency power supply, LC antiresonant circuit wherein is made of the second resonant capacitance 33C1, the 3rd resonant capacitance 33C2 and the second vibration inductance 33L2.Wherein, the anodal in parallel rear of second, third resonant capacitance is connected with the positive output end of median filter circuit 33L1, is connected with the negative output terminal of rectifier 32TH1-6 and the negative input end L-of Single-Phase Inverter Source after the negative pole parallel connection of second, third resonant capacitance; The output of one end and the median filter circuit of the second vibration inductance be connected the positive pole of resonant capacitance and be connected, second other end that vibrates inductance is connected with the positive input terminal L+ of Single-Phase Inverter Source.
Course of work summary of the present utility model:
What is called in the technical program " double resonance ", referring to needs inductance and the Parallel-connected Capacitor resonance except load coil (being load circuit), input at inverter, increased again second an inductance capacitor resonant tank (referred to as the LC antiresonant circuit, lower same), this just consists of the parallel thyristor intermediate frequency power supply of double resonance.
In Fig. 3, three-phase alternating-current supply provides three-phase alternating-current supply by main power source main circuit breaker (not shown) to whole supply unit.
33TH1-6 is the three-phase fully-controlled rectifier, and its Main Function is to send the arteries and veins signal by master board (belonging to control loop, not shown) to regulate the thyristor angle of flow, to realize the control to the induction heater watt level.
33L1 is direct current median filter circuit, and its effect provides the inverter constant current source, avoids the undue decline of loaded quality factor Q value; As the filtering link, make output current Id continuous and straight, ripple is less; Play the buffer action between inverter and rectifier current transformer, the medium, high frequency electric current when making LC resonance can not enter in the common frequency power network and go; Moreover be that inverter plays the effect of restriction transient short-circuit current as short circuit when the inverter failure.
The second resonant capacitance 33C1, the 3rd resonant capacitance 33C2 and the second vibration inductance 33L2 consist of the inverter input terminal resonant tank:
Principle is based on the series and parallel connections resonant frequency equation:
Here key is the selection of resonance frequency, and namely the resonance frequency of inductance and electric capacity will approach with the switching frequency of inverter, so will accomplish the coupling design.
If, there is not inverter to enter to hold resonant tank, then be exactly that direct voltage is directly supplied with inverter.
Adopt the main feature of double-resonant circuit structure that three aspects: is arranged: the one, load current has been transformed into sine wave by square wave, loss can effectively be reduced so that the power device of inverter switch is hit; The 2nd, power device of inverter is reduced by the damaged condition of current changing rate; The 3rd, can greatly simplify the protective circuit of power device.Because inverter is the essential elements of thyristor type parallel resonance intermediate frequency power supply, this unit quality has determined the reliability of whole power supply equipment.
34TH1-8 is inverter, and this is a single-phase bridge type inverter, and every brachium pontis is by two Thyristors in series, in turn conducting by diagonal thyristor on the brachium pontis realizes the change of current, generally to enter end be direct current to inverter, and the voltage that obtains in the load is sinusoidal wave, and electric current then is non-sinusoidal square wave; After having increased the inverter input terminal resonant tank in the technical program, then all can obtain sinusoidal voltage and current waveform in load.
34L1 is induction heater, and induction heating is electrical energy transfer to be given the metal that will heat by induction coil, and then electric energy changes heat energy in metal inside.Induction coil does not directly contact with being heated metal, and energy transmits by electromagnetic induction.
Produce eddy current in the principle of induction heating and the general electric equipment and eddy current causes that the principle of heating is identical, different eddy current in general electric equipment are to be harmful to, and induction heating utilizes eddy current to heat.Like this, induced potential produces induced current (eddy current) I in workpiece, makes the workpiece heating.Its Joule heat is:
Q=0.24I
2Rt
In the formula, Q is the heat (J) that electric current produces by resistance; I is current effective value (A); R is the equivalent resistance (Ω) of workpiece.
Can find out from formula, induced potential is relevant with the magnetic field power with the frequency height with heating power.The electric current that flows through in the induction coil is larger, and the magnetic flux of its generation is also just larger, and the electric current that therefore improves in the induction coil can make the eddy current that produces in the workpiece strengthen; The same operating frequency that improves also can make the induced current in the workpiece strengthen, thereby increases heating effect, workpiece is heated up faster.In addition, the size of eddy current is relevant with cross-sectional sizes, cross sectional shape, conductance, permeability and the depth of penetration of metal.
34C1 is the first resonant capacitor, because the induction coil 34L1 of induction heater is large inductance characteristic, must will mate suitable electric capacity, allows inductance and electric capacity produce resonance; Owing to there being the phase difference of 180 degree, just in time realized the complementation of energy, so resonant capacitor is also referred to as power factor compensation capacitance between the two.
30TH1 is starting circuit, and starting circuit is the effect of resonant capacitor (inductor coil) makeup energy specially.So-called starting is exactly in advance to the charging of the compensation condenser (or inductor coil) in the load circuit, then make and produce damped oscillation in the resonant circuit, thereby make the load circuit starting of oscillation, form attenuated oscillation at load circuit, thereby detect oscillator signal by control system, produce to trigger the triggering signal of the thyristor of inverter, allow system's starting operation.
In the technical program, input at inverter has increased the 2nd a LC antiresonant circuit, and the numerical value of inductance L, capacitor C is considered (being inverter switching frequency) by the load circuit resonance frequency, and given among Fig. 3 is the simplest LC parallel oscillatory circuit.
The LC oscillating circuit not to extraneous space radiation electromagnetic wave, is proper closed circuit (when inverter is worked, just be equal to L, C and load circuit and be in series) when electromagnetic viscosimeter occurs.
Here, lc circuit inside only occur coil magnetic field can and the capacitor electrode field energy between mutual conversion.Electric current that size and Orientation all changes with the cycle (inverter switching frequency) can be produced oscillating current, the circuit of oscillating current can be produced oscillating circuit.
Oscillating current is a kind of alternating current, is the very high alternating current of a kind of frequency, and it can't be given birth at magnetic field transfer movable property with coil, can only be to be produced by oscillating circuit.
Qualitative analysis discharges and recharges: charge complete (discharge beginning): electric field energy reaches maximum, and magnetic field energy is zero, induced current I=0 in the loop.Discharge off (charging beginning): electric field energy is zero, and it is maximum that magnetic field energy reaches, and induced current reaches maximum in the loop.Charging process: electric field energy is increasing, and magnetic field energy is reducing, and electric current is reducing in the loop, and electric weight is increasing on the capacitor.From taking temperature: magnetic field energy is transforming to electric field energy.Discharge process: electric field energy is reducing, and magnetic field energy is increasing, and electric current is increasing in the loop, and the electric weight on the capacitor is reducing.From taking temperature: electric field energy is transforming to magnetic field energy.In oscillating circuit, produce in the process of oscillating current, the electric charge on the capacitor plate, by the electric current of coil, and magnetic field and all generating period variations of electric field of following electric current and electric charge to interrelate, this phenomenon is electromagnetic viscosimeter.
The maximum characteristics of this circuit structure are: if still cancel the resonant circuit of inverter input terminal, power-supply system is exactly conventional intermediate frequency power supply system, and the electric current of intermediate frequency waveform that load circuit obtains is the square wave that changes in the cycle.If behind the resonant tank of access inverter input terminal, the electric current of intermediate frequency waveform that load circuit obtains has been exactly the sine wave of cycle variation.In other words, after this LC oscillating circuit cancellation, original circuit can work equally, is exactly a typical conventional current source thyristor intermediate frequency power supply.
After adopting technique scheme, resulting load waveform as shown in Figure 4.As seen from the figure, load current 4 ' be transformed into sine wave by the square wave among Fig. 1, because the current changing rate at load two ends is effectively reduced, loss can effectively be reduced so that the power device of inverter switch is hit, the efficient of whole supply unit is improved, can effectively alleviate contrary devices switch loss, improve the reliability of whole supply unit.
Because relating to the part of conventional thyristor parallel resonance intermediate frequency power supply in the technical program is prior art, therefore its detail and the course of work are no longer narrated.
Through the test analysis contrast, the intermediate frequency power supply of the technical program improves about 10% than the efficient of the conventional intermediate frequency power supply that does not increase the inverter input terminal resonant tank.Such as: under same operating mode, heated parts temperature 40 degree, this double resonance formula thyristor intermediate frequency power supply only needs the input power of 600KW, adopts conventional intermediate frequency power supply that the input power of 800KW then need be provided.
This is that the again technological break-through of hoisting device efficient, reliability and fail safe can be widelyd popularize in from now on production domesticization project again after applicant unit one belongs to substituted introduction enforcement production domesticization intermediate frequency power supply to the intermediate frequency power supply equipment.
Claims (5)
1. a double resonance formula thyristor intermediate frequency power supply comprises the main power source circuit breaker, three-phase fully-controlled rectifier, median filter circuit, Single-Phase Inverter Source and the induction heating load circuit that connect successively, it is characterized in that:
Between described median filter circuit and Single-Phase Inverter Source, the inverter input resonant tank is set;
The corresponding connection of output of the input of described inverter input resonant tank and median filter circuit;
The connection corresponding to the input of Single-Phase Inverter Source of the output of described inverter input resonant tank.
2. according to double resonance formula thyristor intermediate frequency power supply claimed in claim 1, it is characterized in that described inverter input resonant tank series connection is arranged between median filter circuit and the Single-Phase Inverter Source.
3. according to double resonance formula thyristor intermediate frequency power supply claimed in claim 1, it is characterized in that described inverter input resonant tank is the LC antiresonant circuit.
4. according to double resonance formula thyristor intermediate frequency power supply claimed in claim 3, it is characterized in that described LC antiresonant circuit is made of the second resonant capacitance and the second vibration inductance, the two ends of its described the second resonant capacitance are respectively with the corresponding connection of positive and negative output of median filter circuit; One end of described the second vibration inductance is connected with the positive output end of median filter circuit and the positive terminal of resonant capacitance, and the other end of described the second vibration inductance is with the corresponding connection of positive input terminal of Single-Phase Inverter Source.
5. according to double resonance formula thyristor intermediate frequency power supply claimed in claim 3, it is characterized in that described LC antiresonant circuit is made of the second resonant capacitance, the 3rd resonant capacitance and the second vibration inductance, wherein, the anodal in parallel rear of described second, third resonant capacitance is connected with the positive output end of median filter circuit, is connected with the negative output terminal of median filter circuit and the negative input end of Single-Phase Inverter Source after the negative pole parallel connection of described second, third resonant capacitance; The output of one end and the median filter circuit of described the second vibration inductance be connected the positive pole of resonant capacitance and be connected, described second other end that vibrates inductance is connected with the positive input terminal of Single-Phase Inverter Source.
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105553305A (en) * | 2015-12-25 | 2016-05-04 | 西安奥邦科技有限责任公司 | System optimization method for parallel resonance medium-frequency power supply inverter |
CN114244147A (en) * | 2021-12-17 | 2022-03-25 | 四川大学 | Electromagnetic field coupling generation device and method for electromagnetic strengthening treatment |
-
2012
- 2012-10-30 CN CN2012205611972U patent/CN202906748U/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105553305A (en) * | 2015-12-25 | 2016-05-04 | 西安奥邦科技有限责任公司 | System optimization method for parallel resonance medium-frequency power supply inverter |
CN114244147A (en) * | 2021-12-17 | 2022-03-25 | 四川大学 | Electromagnetic field coupling generation device and method for electromagnetic strengthening treatment |
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