CN102790522A - Realization method for high interference immunity power supply - Google Patents
Realization method for high interference immunity power supply Download PDFInfo
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- CN102790522A CN102790522A CN2012102717467A CN201210271746A CN102790522A CN 102790522 A CN102790522 A CN 102790522A CN 2012102717467 A CN2012102717467 A CN 2012102717467A CN 201210271746 A CN201210271746 A CN 201210271746A CN 102790522 A CN102790522 A CN 102790522A
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Abstract
A realization method for a high interference immunity power supply comprises the following steps: 1), frequency conversion, the specific way is that an LC low pass filter, a DC rectifier converter and an AC generator are sequentially encapsulated in a shielding box which is not grounded, but connected with a circuit; an AC or DC input power supply of 85-265 V is converted into high-frequency AC wave higher than 50 kHz to serve as a transmission energy source; and a sawtooth wave signal generated by the AC generator is changed into an AC signal through shaping, and then the AC signal is output through a push-pull circuit driver transformer; 2), isolation, the specific way is that the high-frequency AC wave higher than 50 kHz obtained in step 1) is subjected to isolation transformation and power transmission through an isolation transformer; the isolation transformer is encapsulated through pouring glue after being manufactured, and whereas the discrete coupling capacitance value between the input and output of the transformer is not larger than 10 pF, the withstand voltage is not lower than 20 kV; and 3), voltage stabilization, the specific way is that the high-frequency AC wave obtained in the step 2), which is isolated by the transformer, is subjected to voltage stabilization to output as a DC power supply of 12 V. The method has the characteristic of high interference immunity.
Description
Technical field
The invention belongs to power technique fields, shield electromagnetic is disturbed, and is the high anti-interference power supply of photo-electricity mutual-inductor testing equipment and other on-line monitoring power devices, is specifically related to a kind of implementation method of high anti-interference power supply.
Background technology
Along with the development of national grid about strong intelligent grid, each item performance index of monitoring equipment are had higher requirement, therefore, application performance is reliable, and the smart machine with high sensitivity, high accuracy, high stability naturally becomes trend of the times.Yet the development of photo-electricity mutual-inductor at present is unsatisfactory, and instrument transformer accident, data monitoring are not in place, and Monitoring Data is lost the equifrequency life that takes place frequently.Everybody has produced suspection to the reliability of photo-electricity mutual-inductor.The development of photo-electricity mutual-inductor has received and having seriously influenced, and some area has begun to limit the installation of photo-electricity mutual-inductor.Revealed that according to the insiders since autumn in 2011, the electronic mutual inductor of one of core components and parts is breakdown again and again in the demonstration intelligent substation project of building up in the first batch, the incident of blasting.There are Nan Rui, Xinning photoelectricity etc. in the electronic mutual inductor manufacturer that relates to.On February 15th, 2012; 500 meters, 13 groups of east sides, emerging farm, Heilungkiang Qitaihe City north, near Sapporo highway next door; The nervous debugging of northern emerging 220 kv substations that just built up, the electronic mutual inductor built-in electrical insulation is by electrical breakdown suddenly, and instrument transformer is blasted in the twinkle of an eye.State Grid Corporation of China builds up the problem that the electronic mutual inductor in the intelligent substation that puts into operation exposes to all and did statistics; Failure rate is up to 5%; " about the notice of practical reinforcement electronic mutual inductor operational management " (calling in the following text: " notice ") file in issue on January 13rd, 2012 shows; State net company proposes to reduce the measure of risk to the electronic mutual inductor fault highly vigilant of that takes place frequently.File claims that " in recent years, along with the development of company's intelligent grid, existing nearly 2000 various types of electric mutual inductors put into operation.Ruuning situation shows that because part producer designed capacity is not strong, technology controlling and process is not tight, and test testing equipment imperfection far above traditional instrument transformer, has caused certain influence to electric power netting safe running in the failure rate of transporting electronic mutual inductor." " notice " require the subordinate respectively move branch company, " when protective relaying device does not carry out integral body or most of the transformation, should not instrument transformer be replaced by electronic mutual inductor; Based on the maturity and the cost performance of present stage electronic mutual inductor, wouldn't carry out digital improvement to 35 kilovolts and following instrument transformer." state's net power transmission and transformation announcement first concentrated project for bidding in 2012, though the intelligent substation fltting speed is still very fast, instrument transformer bid scale then glides 18.04%.
Cause one of them important reasons very of instrument transformer problem, employed exactly power supply does not pass a test.The power supply power pack is one of core of system, in the moment of carrying out the circuit breaker action, can take place with high-frequency harmonic and high-intensity magnetic field, and moment is raised earth potential.And these make the arch-criminal of power supply moment inefficacy just.So guarantee the reliable of instrument transformer, will guarantee the reliable of power supply, truly realize anti-interference to high-frequency harmonic and high-intensity magnetic field.The instrument transformer potential safety hazard that elimination is caused by power supply.Therefore, the anti-interference of power supply of development with high Immunity Performance just becomes the technical scheme that needs to be resolved hurrily.Its appearance also will have vast market prospect.Simultaneously, to advancing intelligent power station process, the popularization of electric mutual inductor has great important.
Instrument transformer and measuring system, power supply etc. are in the environment work of a highfield, high electric field for a long time, need good electromagnetic compatibility effect.In circuit breaker action moment, bigger harm can appear in this interference, earth potential is brought up to several ten thousand volts such as moment.This current potential in power supply and acquisition circuit, makes equipment moment that wrong, phenomenon such as disorderly take place with the Pattern perturbation of common mode and DM EMI, and severe patient also can cause the expendable damage of device.Existing on the market power supply can only be realized the anti-interference of stationary stage.And because the instantaneity of instantaneous interference, very difficult electric field, the Distribution of Magnetic Field situation of gathering and observing moment, also not good corresponding concrete solution in the prior art scheme.
Summary of the invention
In order to overcome the shortcoming of above-mentioned prior art; The implementation method that the purpose of this invention is to provide a kind of high anti-interference power supply; Power supply frequency conversion principle is merged with the AC transformer separation principle mutually, realize the discrete transmission of power and energy, and satisfy the stability of power supply output simultaneously; For the reliably working of photo-electricity mutual-inductor testing equipment and other on-line monitoring equipment provides stable, safe unperturbed voltage, suppress the electromagnetic field glitch.
To achieve these goals, the technical scheme of the present invention's employing is:
A kind of implementation method of high anti-interference power supply may further comprise the steps:
1) frequency conversion; Specific practice is: LC low pass filter, direct current rectifier converter, ac generator are encapsulated in the shielding box in order, and shielding box does not connect the earth, only links to each other with circuit; Utilization Switching Power Supply frequency conversion principle; With exchanging or direct-current input power supplying 85v～265v changes high-frequency ac ripple more than the 50KHz into as the transmission of power source, exchange variator and produce sawtooth signal and become AC signal through shaping, export through the push-pull circuit driving transformer;
2) isolate, specific practice is: the high-frequency ac ripple more than the 50KHz of step 1) is carried out isolated variable and power delivery through isolating transformer;
Said isolating transformer with the encapsulating encapsulation, does not allow to use shielding box after making, the discrete coupling capacitance between the transformer input and output is not more than 10pF, the withstand voltage 20KV that is not less than between the input and output;
3) voltage stabilizing, specific practice is: in the shielding box of encapsulation, with step 2) high-frequency ac ripple voltage stabilizing after the transformer isolation is the power supply output of direct current 12V.
Said shielding box connects the earth.
Said direct current 12V must shield and filtering, adopts to cut-off the filter circuit of instantaneous frequency to circuit breaker specially, suppresses the high voltage that the circuit breaker cut-offs (DM EMI of 100V～10000V).
The invention has the beneficial effects as follows:
Switching Power Supply frequency conversion principle, power delivery technology, AC transformer separation principle, filtering technique are merged in the present invention; The present invention can weaken the interference of transient electromagnetic field and static electromagnetic field significantly, for the equipment of working under the various adverse circumstances provides pure electric energy.Through isolating and not having the cooperation of holding inductance, noninductive electric capacity, realize high-frequency suppressing to disturbing, reach the effect of near-sighted battery.And the present invention has economic worth most be: can utilize the present invention, realize multistage cascade, thereby adapt to the more interference environment of Gao Gengqiang, but need not increase too many investment-final theory of the present invention that Here it is.Compared with prior art, power parameter of the present invention is: existing power supply output accuracy 1%, power supply output accuracy 1% of the present invention; Existing power supply output ripple 1%, power supply output ripple 1% of the present invention; The withstand voltage 2KV of existing power supply input and output, the withstand voltage 20KV of power supply input and output of the present invention; Existing power supply input and output coupling 1000pF, power supply input and output coupling 10pF of the present invention; Existing power supply disturbs and suppresses 2KV, and power supply of the present invention disturbs and suppresses 20KV; Existing power supply disturbs and suppresses several amperes, and power supply of the present invention disturbs and suppresses tens amperes.
Description of drawings
Fig. 1 is a process structure block diagram of the present invention.
Fig. 2 is a frequency conversion theory diagram of the present invention.
Fig. 3 is a separation principle block diagram of the present invention.
Fig. 4 is a principle of stabilized voltage block diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing the present invention is done further explain.
Referring to Fig. 1, a kind of implementation method of high anti-interference power supply may further comprise the steps:
1) frequency conversion, specific practice is: LC low pass filter, alternating current-direct current rectifier converter, ac generator are encapsulated in the shielding box in order, and shielding box does not connect the earth; Only link to each other with circuit, utilization Switching Power Supply frequency conversion principle will exchange or direct-current input power supplying 85v～265v; Through the LC low pass filter, the high frequency clutter on the filtering input power supply allows low-frequency power to pass through earlier; Send into direct current rectification frequency converter again and change the above high-frequency ac ripple of 50KHz into as the transmission of power source; Exchange variator and produce sawtooth signal and become AC signal, through the output of push-pull circuit driving transformer, referring to Fig. 2 through shaping;
2) isolate; Specific practice is: the high-frequency ac ripple more than the 50KHz of step 1) is carried out isolated variable and power delivery through isolating transformer, and the T1 isolating transformer is isolated primary and secondary signal, and the T2 driving transformer carries out secondary isolation to signal; And the lifting signal power, referring to Fig. 3;
The encapsulating encapsulation did not allow to use shielding box after said isolating transformer completed, and the discrete coupling capacitance between the transformer input and output is not more than 10pF, the withstand voltage 20KV that is not less than between the input and output;
3) voltage stabilizing, specific practice is: in the shielding box of encapsulation, with step 2) high-frequency ac ripple voltage stabilizing after the transformer isolation is ripple coefficient 1%, precision 1%; The power supply output of direct current 12V, specific practice is, through the fast diode rectification; Choke and capacitor filtering, 50KHz exchange the source of ripple as rectification circuit, are input in the rectification circuit; To exchange the ripple bridge rectifier is the direct current ripple, accomplishes the variation pattern between the input and output of DC/DC power supply through voltage stabilizing circuit, and the Voltage stabilizing module voltage stabilizing is to 12V output; And realize protected modes such as output short-circuit, overload causing the damage of power supply to prevent external fault with protective circuit.Guarantee the safe and reliable operation of power supply, referring to Fig. 4.
Said shielding box connects the earth.
Said direct current 12V must shield and filtering, adopts special to cut-off instantaneous frequency to circuit breaker
Filter circuit suppresses the high voltage that the circuit breaker cut-offs (DM EMI of 100V～10000V).
When voltage or the rapid variation of electric current generation, will produce the electromagnetic radiation phenomenon, cause electromagnetic interference.
According to electromagnetic theory, the electric current that changes in the conductor radiation that can generate an electromagnetic field, current changing rate (frequency) is high more, and then radiation efficiency is high more.Therefore the electronic equipment of any dependence high-frequency current work all can produce the electric field wave radiation when work.These electric field wave can produce near sensitive equipment and disturb.
The electromagnetic compatibility three elements: any emc issue all comprises three key elements, and promptly interference source, responsive source and coupling path lack one in these three key elements, and electromagnetic compatibility problem just can not exist.Therefore, when solving electromagnetic compatibility problem, also to start with and analyze, investigate thoroughly what these three key elements are, then as the case may be, take adequate measures to eliminate one of them from these three key elements.
The approach of energy transmission: spread out of in the electromagnetic energy slave unit or the approach that imports equipment from the external world into has only two, one be with form of electromagnetic wave from spatial transmission, another is that form with electric current is along wire spread.Therefore, electromagnetic interference emission can be divided into: conduction emission and radiated emission; Susceptibility also can be divided into conducted susceptibility and radiated susceptibility.
The application of impulse circuit has just caused serious day by day electromagnetic compatibility problem.This is because pulse signal has abundant harmonic wave, therefore corresponding very wide frequency spectrum.Can obtain the frequency spectrum of pulse signal with fourier series (to periodic pulse signal) or Fourier transform (to nonperiodic signal).
Abbreviation during electromagnetic compatibility is analyzed: when analyzing electromagnetic compatibility problem, have two specific conditions to utilize, make problem reduction.One is not consider phase place usually, only considers the amplitude of frequency spectrum; Another is to consider worst case usually.Therefore, in analysis, often frequency spectrum is represented with the envelope of amplitude peak.
The spectrum envelope of cyclic pulse signal: shown in the figure is the spectral enveloping line of cyclic pulse signal.The frequency spectrum that periodic signal is corresponding is a discrete spectrum, and the distance of every spectral line is the integral multiple of pulse repetition frequency.Two flex points are arranged on this envelope, and one at 1/ π d place, and another is at 1/ π tr place.Below 1/ π d, the envelope amplitude remains unchanged, and between 1/ π d to 1/ π tr, amplitude descends with the speed of 20dB/dec, more than 1/ π tr, descends with 40dB/dec.The frequency of 1/ π tr is called the bandwidth of pulse signal.The rise time of pulse signal is short more, and then the frequency band of signal is wide more.
The frequency spectrum of aperiodic pulse signal:, therefore represent with spectrum intensity because the frequency spectrum of aperiodicity pulse signal is a continuous spectrum.Spectrum intensity measures with the signal strength signal intensity in certain frequency band, and for example for voltage: unit is dBV/MHz, and for electric current, unit is dBA/MHz.For the certain pulses signal, spectrum intensity is:
f＜1/πd：V＝6+20lg?AT(dBV/MHz)
1/πd＜f＜1/πtr：V＝20lg?A-4-20lg?f(dBV/MHz)
f＞1/πtr：V＝-14+20lg?A-20lg?tr-40lg?f(dBV/MHz)
In the formula: the unit of pulsewidth d, cycle T and rise time tr is μ s, and the unit of f is MHz.
If the result is not normalized to 1MHz, add that then the modifying factor of the bandwidth B formation of being considered gets final product: 20lgB, the unit of B are MHz.
Interference on the cable is divided into two kinds in common mode disturbances electric current and DM EMI electric current according to the flow path of disturbance current; Owing to inequality, therefore before carrying out filter design, must understand the kind of the disturbance current of being faced to the filtering method of these two kinds of disturbance currents.
The common mode disturbances electric current: amplitude/phase is identical on disturbance current all leads in cable, flows in the loop that it forms between cable and the earth.Cause the reason of the electric current of this interference to have three, one is to induce voltage (this voltage is the constant amplitude homophase with respect to the earth) on external electromagnetic field all leads in cable, and this voltage produces electric current; Another reason is owing to due to the earth potential difference that equipment connect at cable two ends, under the driving of this ground voltage, produce electric current; The 3rd reason is between cable and the earth on the equipment potential difference to be arranged, and has common mode current on the cable like this.
From defining easy understanding, common mode current itself can't exert an influence to circuit, has only when common mode current changes differential-mode current (voltage) into, just can exert an influence to circuit.This situation occurs under the unbalanced situation of circuit.
In addition, if equipment produces common mode current on its cable, then cable can produce strong electromagnetic radiation, causes equipment can not satisfy in the electromagnetic compatibility standard requirement for restriction to radiated emission, or miscellaneous equipment is caused interference.
The DM EMI electric current: disturbance current flows at (or between live wire and zero line of power line) between holding wire and the signal ground.In signal cable, the DM EMI electric current is to be induced in the loop that holding wire and signal ground constitute by external electromagnetic field.Because holding wire and its ground wire in the cable lean on very closely, the loop area that therefore forms is very little, so the differential-mode current of external electromagnetic field induction generally can be very not big.In power line, (its amplitude is often very big) that produces when (particularly Switching Power Supply) that the DM EMI electric current is launched by the power supply of other electrical equipment on the electrical network often and inductive load break-make.The DM EMI electric current all can directly influence the work of equipment.
The parasitic capacitance of inductance coil is from two aspects, and one is the electric capacity between the every circle of coil, and another is the electric capacity between winding wire and the magnetic core.Reduce electric capacity and also just blocked interference source.
When inductance core was non-conductor, turn-to-turn capacitance was main, and when magnetic core was conductor, the electric capacity between lead and the magnetic core was main.
The present invention can weaken the interference of transient electromagnetic field and static electromagnetic field significantly, for the equipment of working under the various adverse circumstances provides pure electric energy.Through isolating and not having the cooperation of holding inductance, noninductive electric capacity, realize high-frequency suppressing to disturbing, reach the effect of near-sighted battery.And the present invention has economic worth most be: can utilize the present invention, realize multistage cascade, thereby adapt to the more interference environment of Gao Gengqiang, but need not increase too many investment-final theory of the present invention that Here it is.
Embodiment
Choose 50KHz as the output of frequency-changing AC ripple, adopt two transformers to isolate transmission, in the transformer winding process, the spacing that requires optional position between input coil, iron core, the output winding three is all greater than 2mm.It is withstand voltage that the input and output side of each transformer reaches 12KV.In the level Filter Design of back, adopt noninductive electric capacity nominal 8nF, there is not the inductance of appearance 30uF, suppress passing through of the above High-frequency Interference of 100KHz.
Claims (3)
1. the implementation method of a high anti-interference power supply is characterized in that, may further comprise the steps:
1) frequency conversion; Specific practice is: LC low pass filter, direct current rectifier converter, ac generator are encapsulated in the shielding box in order, and shielding box does not connect the earth, only links to each other with circuit; Utilization Switching Power Supply frequency conversion principle; With exchanging or direct-current input power supplying 85v～265v changes high-frequency ac ripple more than the 50KHz into as the transmission of power source, exchange variator and produce sawtooth signal and become AC signal through shaping, export through the push-pull circuit driving transformer;
2) isolate, specific practice is: the high-frequency ac ripple more than the 50KHz of step 1) is carried out isolated variable and power delivery through isolating transformer;
Said isolating transformer with the encapsulating encapsulation, does not allow to use shielding box after making, the discrete coupling capacitance between the transformer input and output is not more than 10pF, the withstand voltage 20KV that is not less than between the input and output;
3) voltage stabilizing, specific practice is: in the shielding box of encapsulation, with step 2) high-frequency ac ripple voltage stabilizing after the transformer isolation is the power supply output of direct current 12V.
2. the implementation method of a kind of high anti-interference power supply according to claim 1 is characterized in that, said shielding box connects the earth.
3. the implementation method of a kind of high anti-interference power supply according to claim 1; It is characterized in that; Said direct current 12V must shield and filtering, adopts to cut-off the filter circuit of instantaneous frequency to circuit breaker specially, suppresses the high voltage that the circuit breaker cut-offs (DM EMI of 100V～10000V).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114256806A (en) * | 2021-12-14 | 2022-03-29 | 中国船舶重工集团公司第七0四研究所 | Solid state circuit breaker with one-way blocking filter |
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| CN101236827A (en) * | 2007-03-30 | 2008-08-06 | 广州市中奕通讯设备有限公司 | Method and product for solving the electromagnetic compatibility of no Y capacitance switch power transformer |
| CN201450449U (en) * | 2009-04-03 | 2010-05-05 | 东南大学 | Widely adjustable voltage frequency device |
| CN201656766U (en) * | 2010-03-30 | 2010-11-24 | 合肥吉源电子有限公司 | Low-E high-voltage input module power supply |
| CN102139244A (en) * | 2011-02-16 | 2011-08-03 | 王红星 | High frequency power supply for electric dust removal |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN2132337Y (en) * | 1992-07-15 | 1993-05-05 | 唐山市电视机厂 | Switch type sine wave power conversion device |
| CN1822740A (en) * | 2006-03-18 | 2006-08-23 | 阮树成 | Electronic ballast of high performence eliminating electromagnetic interference |
| CN101236827A (en) * | 2007-03-30 | 2008-08-06 | 广州市中奕通讯设备有限公司 | Method and product for solving the electromagnetic compatibility of no Y capacitance switch power transformer |
| CN201450449U (en) * | 2009-04-03 | 2010-05-05 | 东南大学 | Widely adjustable voltage frequency device |
| CN201656766U (en) * | 2010-03-30 | 2010-11-24 | 合肥吉源电子有限公司 | Low-E high-voltage input module power supply |
| CN102139244A (en) * | 2011-02-16 | 2011-08-03 | 王红星 | High frequency power supply for electric dust removal |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114256806A (en) * | 2021-12-14 | 2022-03-29 | 中国船舶重工集团公司第七0四研究所 | Solid state circuit breaker with one-way blocking filter |
| CN114256806B (en) * | 2021-12-14 | 2024-11-12 | 中国船舶重工集团公司第七0四研究所 | Solid-state circuit breaker with unidirectional current limiting filter |
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Application publication date: 20121121 |