CN202602381U

CN202602381U - Power supply device of current transformer

Info

Publication number: CN202602381U
Application number: CN2012201764235U
Authority: CN
Inventors: 关平
Original assignee: SHENZHEN STM TECHNOLOGY Co Ltd
Current assignee: SHENZHEN STM TECHNOLOGY Co Ltd
Priority date: 2012-04-24
Filing date: 2012-04-24
Publication date: 2012-12-12
Anticipated expiration: 2022-04-24

Abstract

The utility model discloses a power supply device of a current transformer. The device comprises a CT, a first bridge rectifier circuit, a residual current discharge switch, a diode, an LC filter circuit, an input voltage sampling circuit, a reference voltage forming circuit, a return difference comparison circuit, a drive circuit and an isolation high-frequency switch pulse width modulation DC/DC (direct current) conversion multi-path output stabilized-voltage power supply circuit. In the utility model, an electronic switch discharges the residual current output by the CT and intermittently extracts the required energy from the CT so as to limit the output overvoltage of the CT and prevent the CT saturation. The high-voltage input high-frequency switch power technology is adopted to increase the extracted voltage and reduce the output current of the CT, thus the heat generated by the CT and the rectifier circuit and the current discharge switch after the CT is reduced, and the power extraction efficiency is improved.

Description

A kind of current transformer power supply device

Technical field

The utility model relates to a kind of high frequency switch power technology and practical application thereof from current transformer (CT) power taking, belongs to the application of power electronic technology in the intelligent grid terminal equipment.

Background technology

In intelligent grid terminal monitoring equipment uses (electrical power distribution automatization system is most typical case), often become very crucial problem how for the power supply of high pressure on-site monitoring equipment.When for example high-tension overhead line, feeder switch, power cable and power supply unit etc. being monitored; Neighbouring generally all do not have suitable low-tension supply can supply watch-dog to use; In addition under certain conditions; Because the power circuit high-low pressure must be isolated, even low-pressure side has ready-made power supply to use.

Traditional, also be at present the most frequently used these terminal monitoring power devices methods of giving: utilize voltage transformer (PT) power taking from the high-tension line; PT converts the high pressure industrial-frequency alternating current into the low pressure industrial-frequency alternating current of 110V or 220V; The working power, the switching manipulation power supply that transfer terminal monitoring equipment again through the AC/DC conversion electric power to; For the system that backup battery is arranged, also need offer the charge power supply of charge in batteries.This method custom is called the PT method for power supplying, and there is following shortcoming in the PT method for power supplying:

1. the PT volume is big, must be installed in outside high-tension line main equipment and the terminal monitoring equipment, and difficult installation, it is big to take up room.

2. PT is installed in the open air, suffers the destruction of electrical network resonance, thunderbolt, burn into external force etc. easily, and damage probability is very high.

3. the PT finite capacity has generally satisfied not requirement, if will increase capacity then need reduce precision, can't satisfy measurement requirement so again, and the two is difficult for taking into account.

4. the PT cost is high.

Electrical power distribution automatization system requires when normal operation of electric power system and fault, can both monitor and fault judgement a circuit, and takes corresponding protection, adjusting action, so the power supply reliability of electrical power distribution automatization system itself is very important.

Because the PT power supply exists above not enough, people begin to consider other method of supplying power to, wherein have: methods such as CT (current transformer) power taking energy supply, capacitance partial pressure energy supply, pure storage battery energy supply, laser energy supply.

In these method of supplying power to, the capacitance partial pressure energy-provision way is very high to dividing potential drop electric capacity technological requirement, gets can power for a short time, too much uses the capacity current that will increase electrical network and reduces the efficient of transmission of electricity and the reliability of transmission system; Pure storage battery power supply because the life of storage battery is limited, needs periodic replacement, and needs the replacing that has a power failure; And if employing laser powered sensor mode receives the price limit of photocell conversion efficiency and laser diode generator again, involve great expense.

After taking all factors into consideration, people generally believe that the mode of employing current transformer CT power taking energy supply is better.CT power taking method is: CT utilizes the electromagnetic conversion principle to deliver to the secondary side of CT on high-tension side energy, utilizes special technique to come out this Energy extraction again and gives load.This method, it is simple in structure, and is economic and practical, and it and high pressure primary circuit do not have direct electrical link, and work with the high-pressure side equipotential, and be as safe as a house, evaded the high-low pressure isolating problem.

But that is that all right is ripe for existing C T power taking technology, mainly has following problem:

1. CT power taking voltage is low, and the secondary side output current is big, and the electric supply installation conversion efficiency is low, and CT and the heating of power taking electric supply installation thereafter are serious, and the big more situation of input current is serious more, and the reliability of CT and electric supply installation long-time running can't guarantee.

2. the power of power taking is too little, has only several watts, can only satisfy the power demands of the device simple, that power consumption is very little.

3. because load construction lags behind supply line's construction, and the load of newly-built circuit increases gradually, so the real work current range of circuit is very wide, CT power taking electric supply installation must be the monitoring equipment power supply reliably in very wide current range.But it is too narrow that present CT power taking technology can be extracted the current range of power demand reliably, can't take into account big or small electric current, often satisfied not the requirement of using.

4. secondary DC/DC conversion need be increased and the multiple power supplies that monitoring equipment needs could be obtained.

5. feasible but implement difficulty on some technical know-how.

Find that after retrieval following patent and paper have the content that relates to CT power taking technology and electric supply installation.

1) related patent U.S. Patent No.:

1. the patent of Wuhan University application, application number is: 200410061314.9, name is called: the induction electricity getting device that is used for the aerial high voltage power transmission lead.This patent proposes is a kind of with the storage battery reserve CT power taking electric supply installation of the energy in support; Realize to use if desired, there is following problem in this patent: during power that the mechanism that the unnecessary energy that (1) does not provide CT is released, the power that provides as CT need greater than circuit thereafter; The equivalent input impedance of CT circuit thereafter is very big; Be similar to the CT output open circuit, the CT output voltage will continue to raise, up to puncturing circuit thereafter; Therefore this technical scheme can't be reliably from the CT power taking, and this is the topmost defective of this patent.Mention in the patent at relay contact of CT output parallel connection; Device will stop the power taking from CT when the short circuit of this contact; But this contact is to open/close conversion according to the voltage status of the storage battery of electric supply installation; If hope to lean on its unnecessary energy of CT of releasing, at first be that the target of control is not right, secondly battery tension changes hour being the order of magnitude; And the CT excess energy cycle of releasing is a Millisecond, so this relay unnecessary energy that do not have the CT that releases prevents the effect of CT output overvoltage.(2) this patent is described and is used Switching Power Supply to be connected with CT; Convert the output current of CT to voltage through Switching Power Supply; But how electric current is changed into voltage and Switching Power Supply work schedule during this transfer is what kind of has no explanation, and this process be with Switching Power Supply can be reliably from one of key of CT power taking.(3) do not explain that CT can provide the effective power taking current range and the power of required power, this is the key index whether CT power taking technology has practical value.

2. another part patent of Wuhan University application, application number is: 200820066665.2, name is called: high-tension line induction electricity getting device.This is also a kind of with the storage battery reserve patent of the CT power taking electric supply installation of the energy in support.The problem of this patent: (1) this patent has adopted the adjustable linear voltage stabilization integrated circuit LM317 pressure limiting charging circuit of lithium battery in support, and according to the parameter of Fig. 4 wherein, the output voltage that is full of back LM317 at lithium battery voltage is: the pressure drop of 3.675V+D1; The maximum permissible value of the input of LM317-output voltage difference is 40V; Even the reliability LM317 that does not therefore consider device not derate uses, also have only about 44V from the maximum voltage of CT power taking, power taking voltage is too low; When needing identical power; Input current is big, and input current is unfavorable for improving the efficient of power taking greatly, and CT and device will seriously generate heat when big input current.(2) if, improve power taking efficient, be made as power taking voltage the limit input voltage 44V of LM317 in order to reduce input current as far as possible; The input and output pressure reduction of LM317 reaches 40V so, and the LM317 output voltage is about 4V, when that is to say lithium cell charging; The loss of LM317 self-heating is more than 10 times of actual charge power; The efficient of device is extremely low, LM317 heating is very serious, and the volume of CT and device is all little not; If in order to reduce the LM317 loss; The minimum imbalance pressure reduction 3V that is reduced to LM317 to CT power taking voltage both power taking voltage is 7V, and input current will increase more than 6 times so, can reach 20 ~ 110W by the power output of saying in the patent; Input current average value must reach 2.85 ~ 15.7A; Making the earial drainage controllable silicon of CT back, the loss of input rectifying bridge heighten, is that power taking efficient is low equally, and heating is serious.(3) maximum output current of LM317 has only 500mA, reaches two reasons in front in view of the above, patent statement beneficial effect: " power output is big, and voltage is stable, and when the high-tension line electric current was 80 ~ 300A, power output can reach 20W ~ 110W " is incredible.(4) even when the high-tension line electric current is 80 ~ 300A, can export and require power, but the power taking current range still is too narrow, can not satisfy the practical application needs.

3. the patent of Shanghai Communications University application, application number is: 200910309627.4, name is called: based on the ultra-high-tension power transmission line CT electricity getting device of power control method.This patent provides a kind of not with the CT electric supply installation of backup battery.The problem that exists: (1) with a relay carry out CT insert the back rectification circuit and disconnection CT rectification circuit connection and with switching between the CT output short-circuit; Two problems have been done like this; The one, relay CT output in handoff procedure has and is in vacant state blink; CT output allows to open a way anything but, and this will make CT produce circuit and damage CT that very high output voltage punctures the back; The 2nd, the action meeting of relay is very frequent, and approximately a few tens of milliseconds will move once, generally has only hundreds of thousands the mechanical endurance of relay, and so relay was just scrapped in several days.(2) the DC/DC translation circuit that has adopted low pressure to import, the input voltage of statement DC/DC can not surpass 15V in its patent specification.As last patent, too low input voltage means big input current, means that the power of device can not be big, and efficient is low, and the power taking current range is narrow.(3) need carry out power taking control with special single-chip microcomputer, system is too complicated, and the dynamic responding speed of control is slow, possibly can't effectively control the energy of CT input.

4. the patent of Shanghai Nanhua Lanling Electric Applicance Co., Ltd and Shanghai Electric Power Co application, application number is: 200920210122.8, name is called: a kind of high tension loop switching regulator induction DC power supply.This patent provides a kind of CT direct current power source supplying power, and it is in common CT, to have increased the another one coil for flux control, and through the energy of this coil control CT input power-supply circuit thereafter, the power taking principle is no problem.Its deficiency: that (1) DC/DC partly uses is LM117, and LM117 is actual to be the model of army's grade of LM317, and the temperature range that comparing with LM317 does not exist together is to use is wideer, and other index is basic identical.Therefore also there is the problem (2) of patent 200820066665.2 in this patent, is difficult to accomplish bigger power output and wide power taking current range.(2) needs use the CT of the twin coil of special-purpose band coil for flux control, and the CT volume is big, cost is high.

2) relevant paper

1. paper title: a kind of photoelectric type current transformer power supply power supply that adapts to the bus current wide dynamic range, the unit of delivering: electrical engineering system of Dalian University of Technology, the publication of publication paper: " Proceedings of the CSEE ".This paper provides the technical scheme of the CT power taking electric supply installation of not being with backup battery; Mention with the tapped CT of a kind of second siding ring band; Through detecting the size of judging the high-tension line electric current; Select the different taps of CT secondary coil to change the turn ratio of CT, thereby the output current of CT when improving the little electric current of high-tension line is widened the current range of CT power taking.There is following problem in this scheme when specifically realizing: the CT tap is switched with a relay single-pole double throw contact in (1); In handoff procedure; Because the relay contact action needs certain journey time; Of short duration vacant state appears in the middle CT that will make, CT will produce the circuit puncture thereafter of high output voltage.The operating life of relay is limited in addition, and the reliability of electric supply installation long-term work there is not assurance.(2) electric current that needs detection to judge that high pressure is surveyed is controlled the gearshift of CT second siding ring, detects judgement and arrives control, this process need regular hour again.CT is in the low turn ratio during little electric current, if at this moment come a very big impulse current (like failed because) suddenly, in detecting switching during this period of time, CT second siding ring electric current will be very big, probably burn CT coil and subsequent circuit.What (3) pressurizer adopted is the linear voltage stabilization integrated circuit of low pressure differential, and the linear voltage regulator conversion efficiency is low.(4) CT needs specialized designs, and cost is high.The power output of (5) only under lab accomplishing 0.3W.

Summary of the invention

In order to overcome the deficiency of prior art, the purpose of the utility model is to solve the problem that existing CT power taking technology and device exist, and provide a kind of and can satisfy application request, and practical, technology of CT power taking cheaply and electric supply installation.

The technical scheme that the utility model adopts can be described as:

A kind of current transformer power supply device comprises that release switch, diode, LC filter circuit, input voltage sample circuit, reference voltage of one or more current transformers (CT), first bridge rectifier, residual current forms circuit, return difference comparison circuit, drive circuit, isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit and input peak voltage and suppress circuit; Wherein, High-tension current loop single line passes CT; The induction alternating voltage of CT output becomes direct voltage after the first bridge rectifier rectification; The LC filter circuit carries out smothing filtering to the voltage of first bridge rectifier output, and filtered voltage is delivered to the input of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit, with filtered voltage transformation to be multichannel VD that isolate each other, stable; The residual current switch of releasing is connected between first bridge rectifier and the LC filter circuit; The input voltage sample circuit is connected between LC filter circuit and the isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit; It is gathered the output voltage of LC filter circuit and gives the return difference comparison circuit signal, and the return difference comparison circuit also forms circuit from reference voltage simultaneously and obtains reference voltage signal; The return difference comparison circuit compares the signal of input voltage sample circuit and reference voltage formation circuit;, the signal of input voltage sample circuit thinks the energy surplus of CT output when forming the signal of circuit greater than reference voltage; Return difference comparison circuit signal drives the residual current switch closure of releasing, and releases with the excess current short circuit that CT is produced; During residual current is released switch closure by the capacitor discharge of stored energy in the LC filter circuit; Continue as the circuit supply of its back; When the voltage of electric capacity is reduced to the voltage that makes the input voltage sample circuit when forming the voltage of circuit less than reference voltage; The return difference comparison circuit sends signal and drives the residual current switch of releasing and break off, so circulation with the output voltage stabilization of LC filter circuit within the scope of a setting; Diode is connected on residual current and releases on the circuit between switch and the LC filter circuit, and the energy that is used to prevent LC filter circuit storage when residual current is released switch closure is also released by the residual current switch of releasing; The input peak voltage suppresses the circuit cross-over connection in the two ends of the second siding ring of CT, is used to suppress the too high peak voltage that in the voltage of CT output, possibly contain.

As a kind of improvement of above technical scheme, isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11) is for adopting the DC/DC circuit of high frequency switch power technology.

As a kind of improvement of above technical scheme, the residual current switch of releasing can be connected across on the output of secondary side output winding of CT or is connected across on the output of first bridge rectifier.

As a kind of improvement of above technical scheme, residual current is released switch (3) for adopting the electronic switch of devices formations such as MOSFET, IGBT, triode, controllable silicon, solid-state relay.

A kind of improvement as above technical scheme; The device of the utility model is that the output voltage of LC filter circuit (5) is provided with voltage control point Vu1, Vu2, Vo1; Device is accomplished the control of CT (1) power taking according to said electrical voltage point; Vu1＜Vu2＜Vo1 wherein; Vu1 is the starting resistor of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11), also is the input under-voltage protection point of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11), when isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11) work during greater than Vu1 of LC filter circuit (5) output voltage; Output voltage is during less than Vu1, and isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11) quits work; Vu2 is the residual current electrical voltage point that switch (3) turn-offs of releasing; Vo1 is the residual current closed electrical voltage point of switch (3) of releasing; Residual current switch (3) closure of releasing when the output voltage of LC filter circuit (5) surpasses Vo1; LC filter circuit (5) voltage begins to descend, and the residual current switch (3) of releasing turn-offs when dropping to Vu2.

A kind of improvement as above technical scheme also comprises drive circuit, the amplification rear drive residual current that the signal that the return difference comparison circuit sends carries out power through drive circuit release switch closure or disconnection.

A kind of improvement as above technical scheme; Also comprise the bias supply that is arranged between LC filter circuit and the isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit, it forms circuit, return difference comparison circuit and drive circuitry for reference voltage.

As a kind of improvement of above technical scheme, comprise that also the input peak voltage that is connected between the CT and first bridge rectifier suppresses circuit, be used to suppress the too high peak voltage that in the voltage of CT output, possibly contain.

As a kind of improvement of above technical scheme, also comprise exchanging input protection circuit, power-supply filter, second bridge rectifier, for electric supply installation provides the extra compatible power supply input channel of AC and DC.

The beneficial effect of the utility model is:

The utility model adopts electronic switch that the unnecessary electric current of CT output is released, and from CT, extracts required energy off and on, and the output overvoltage with restriction CT prevents that CT is saturated.The high frequency switch power technology that adopts the high pressure input to be improving power taking voltage, thereby reduces the output current of CT, reduces CT and the heating of rectification circuit, earial drainage switch thereafter like this, improves the efficient of power taking.The DC/DC circuit of high frequency switch power technology is higher than the DC/DC circuit efficiency of linear voltage stabilization, and when particularly input-output pressure reduction was big, this further improved the conversion efficiency of whole electric supply installation.The DC/DC converter technique of adopt isolating does not need second level conversion just can export the multipath voltage regulation power supply simultaneously, and the voltage swing that multichannel is exported can be adjusted according to the high frequency transformer that application need changes DC/DC.

Specifically, the advantage of the utility model is:

1) CT power taking voltage is high.From CT extract same power the time, the CT output voltage is high more, then output current is more little, the loss of CT, rectifier bridge, earial drainage switch is more little, the device heating is little, can guarantee the reliability of long-term work.

2) need not use the rectifier bridge and the switching tube of big electric current, can reduce cost.

3) power of power taking is big, and during same CT output current, power taking power is 10 ~ 20 times of prior art.If desired, the DC/DC circuit of the high frequency switch power technology that adopts in the utility model also can use the more topological structure and the circuit of high working voltage, just can extract bigger power from CT, must satisfy the output requirement but prerequisite is a CT power.

4) the high frequency switch power technology rather than the linear stabilized power supply technology of DC/DC conversion employing are carried out voltage stabilizing, and the efficient of DC/DC conversion is high, and loss is little, and it is little to generate heat, and power output is big.

5) can add secondary DC/DC conversion and can directly export multichannel isolation, the voltage galvanic current source of satisfying the monitoring equipment needs, further raise the efficiency.

6) response speed of earial drainage switch is fast, and the ability that therefore tolerates overcurrent and short-circuit impact is strong, and the ability that suppresses the input overvoltage simultaneously is strong.

7) can connect interchange, direct current, the CT multiple input of supplying power, and wide input voltage range, applied widely.

8) use common CT to get final product,, do not need special-purpose power taking CT, can reduce cost like this as long as CT power can meet the demands.

9) use electronic switch rather than do not have relay, do not exist and cause the unsettled in short-term problem of CT output winding in the relay handoff procedure.

10) the DC/DC operating voltage range is wide, so Hold up ability is strong, and anti-input flickering ability is strong, and electric supply installation output is more stable, reliable.

11) compare with the PT power supply: the volume I is installed in the monitoring equipment of terminal, and cost is low, reliability is high.

Description of drawings

Below in conjunction with accompanying drawing the embodiment of utility model is done further explain.

Fig. 1 is the functional-block diagram of the utility model;

The catenation principle figure of CT and rectification circuit when Fig. 2 adopts many CT power taking for the utility model;

Fig. 3 is the circuit theory diagrams of a specific embodiment of the utility model.

Embodiment

As shown in Figure 1, the device that the utility model proposed suppresses release switch 3, diode 4, LC filter circuit 5, input voltage sample circuit 6, bias supply 7, reference voltage of circuit 12, residual current by power taking current transformer (CT) 1, first bridge rectifier 2, input peak voltage and forms circuit 8, return difference comparison circuit 9, drive circuit 10, isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11, interchange input protection circuit 13, power-supply filter 14, second bridge rectifier 15 and form.

Wherein, High-tension current loop single line passes CT; When flowing through electric current I p in the high tension loop; In the coil of the secondary side of CT, will produce electric current I s, Is ≈ Ip/N, N are the no-load voltage ratios of CT; The circuit that this electric current is flowed through after the CT is transformed into voltage; Before first bridge rectifier 2 was alternating voltage, after 2 rectifications of first bridge rectifier, became direct voltage, and the effect that the input peak voltage suppresses circuit 12 is to suppress the too high peak voltage that in the voltage of CT output, possibly contain; Circuit to first bridge rectifier 2 and back thereof is protected; LC filter circuit 5 carries out smothing filtering with the voltage of first bridge rectifier, 2 outputs, and the voltage behind LC filter circuit 5 smothing filterings is delivered to the input of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11, and isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 is stabilized voltage power supplys of the multichannel output of isolated form HF switch pulse-width modulation DC/DC conversion; It is the voltage transformation of LC filter circuit 5 that (that isolate, the stable each other VD of the middle OUT1 among Fig. 1 ~ OUTn), actual way press actual needs design to the final multichannel that we need.

The release effect of switch 3 of residual current is to import thereafter the excess energy of circuit to CT to release, and does not allow unnecessary energy to get into the circuit of back, gets ability intermittence.Input voltage sample circuit 6 is gathered the output voltage of LC filter circuit 5 and is given return difference comparison circuit 9 signal; Reference voltage forms circuit 8 generation reference voltage signals and also gives return difference comparison circuit 9, is compared the signal that input voltage sample circuit 6 and reference voltage form circuit 8 by return difference comparison circuit 9., the signal of input voltage sample circuit 6 just thought the energy surplus of CT input when forming the signal of circuit 8 greater than reference voltage; Return difference comparison circuit 9 sends immediately and lets the residual current closed signal of switch 3 of releasing; This signal carries out power amplification through drive circuit 10; Drive residual current switch 3 closures of releasing, residual current switch 3 closures of releasing are released the short circuit current that CT produces, and unnecessary energy is shielded in outside first bridge rectifier, 2 late-class circuits.Residual current release switch 3 periods of contact by LC filter circuit 5 in the capacitor discharge of stored energy; Continue as the circuit supply of its back; LC filter circuit 5 is in when discharge, and voltage descends gradually, when the voltage that is reduced to input voltage sample circuit 6 when voltage forms the voltage of circuit 8 less than reference voltage; Return difference comparison circuit 9 sends let residual current release signal that switch 3 breaks off immediately, and signal amplifies through drive circuit 10 and drives the residual currents switch 3 of releasing and break off.So through residual current release switch 3 constantly closed, break off keep LC filter circuit 5 output voltage stabilization within the scope of a setting.The effect of diode 4 is to prevent that the release energy of switch 3 LC filter circuit 5 storages when closed of residual current from also having been released by the residual current switch 3 of releasing.Bias supply 7 is the bias supplies that form circuit 8, return difference comparison circuit 9, drive circuit 10 power supplies for reference voltage.

The residual current switch residual current of releasing is released and can be used metal-oxide-semiconductor, triode, IGBT as switch when switch 3 is placed on like the position among Fig. 1; The residual current switch 3 of releasing also can be connected across the two ends of the secondary side output winding of CT, at this moment can use bidirectional switch devices such as solid-state relay, bidirectional triode thyristor.

Exchange input protection circuit 13, power-supply filter 14, the additional circuit of second bridge rectifier, 15 compositions among Fig. 1; Effect is to provide the another one AC and DC compatible power supply input channel for electric supply installation; Can insert the interchange or the DC power supply of wide region; Purpose is to make electric supply installation can adapt to multiple input mode, can make things convenient for user's commissioning device, and electric supply installation has wideer applicable situation.Exchange the input protection circuit that input protection circuit 13 is made up of protective tube, piezo-resistance, NTC thermistor; The power-supply filter circuit that power-supply filter 14 is made up of common mode filtering inductance, X and Y safety electric capacity; Second bridge rectifier 15 is bridge rectifiers; Exchanging input protection circuit 13, power-supply filter 14, second bridge rectifier 15 all is custom circuit, here with regard to not quite clear describe in detail clear.

Because the secondary side output winding of CT is a current source; The output impedance of current source is infinitely great; Therefore the output voltage of its secondary side is by the equivalent input impedance decision of the size of output current and the circuit that connect thereafter, and during identical output current, the equivalent input impedance of the circuit of back is big more; The output voltage of CT is big more, and the power output of CT is also big more.When the CT power output has surpassed the power output (power that comprises the electric supply installation own loss) of electric supply installation; The CT output voltage will constantly rise; The CT output voltage can not infinitely rise; Must limit, the utility model has adopted above-mentioned with the residual current switch 3 unnecessary output current of CT of releasing of releasing, and extracts the upper limit of output voltage of the method restriction CT of energy off and on from CT.

The CT output current begins to charge to the electric capacity in the LC filter circuit 5 when powering on; Before the output voltage of LC filter circuit 5 does not reach the starting resistor of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11; Isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 is in closed condition; The direct current equivalent input impedance of the circuit of CT back is very big at this moment; The output voltage of LC filter circuit 5 just rises gradually; When the voltage of LC filter circuit 5 reached the starting resistor of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11, isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 was started working and is electric.As long as therefore we make Is_min*Vu1 >=Pout/ η, electric supply installation can in whole power taking current range, stably export power demand [Is_min: the lower limit of power taking current range, CT secondary side output current value; Vu1: the starting resistor value of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11; Pout: the rated output power of electric supply installation; The efficient of the circuit after η: the CT].What isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 adopted in the utility model is isolated form HF switch pulse-width modulation stabilized voltage power supply technology; Input service voltage is high, wide ranges; Input service voltage is the linear voltage regulator that uses in aforementioned publication and the paper, low voltage DC/DC converter 20 times or higher; Therefore under same CT output current, can extract bigger power.The work input range is wide, makes electric supply installation have the longer Hold up time, and stronger anti-input flickering ability is arranged.Adopt isolation of high frequency switch pulse-width modulation voltage stabilizing technique; Than linear stabilized power supply higher conversion efficiency is arranged; Device can be more efficiently from the CT power taking; The stable output of voltage that isolation technology can directly provide multichannel to isolate does not each other need to carry out two-dimensional transform again, further raises the efficiency and simplifies circuit.

The output voltage of filter circuit LC filter circuit 5 has three key points, is respectively Vu1, Vu2, Vo1, Vu1＜Vu2＜Vo1.Vu1 is the starting resistor of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11; It also is the input under-voltage protection point of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11; When isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 work during of LC filter circuit 5 output voltages greater than Vu1; Output voltage is during less than Vu1, and isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 quits work; Vu2 is the residual current electrical voltage point that switch 3 turn-offs of releasing, and Vo1 is the residual current closed electrical voltage point of switch 3 of releasing.Residual current switch 3 closures of releasing when the output voltage of LC filter circuit 5 surpasses Vo1, LC filter circuit 5 voltages begin to descend, and the residual current switch 3 of releasing turn-offs when dropping to Vu2.

Device also can as shown in Figure 2ly utilize a plurality of CT power takings; Release switch 3 and LC filter circuit 5 of CT among Fig. 2, residual current is identical with CT among Fig. 1; First bridge rectifier 2 is identical among first bridge rectifier 2, diode 4, input voltage sample circuit 6 and Fig. 1, and it is identical that bias supply 7, reference voltage form among circuit 8, return difference comparison circuit 9 and Fig. 1 input peak voltage inhibition circuit 12.Many CT power taking can be used in the three-phase high-voltage circuit, can also can only get the wherein electric current of two phases simultaneously from the three-phase current power taking, also can pass the deficiency that a phase current remedies single CT power simultaneously by several CT.

Fig. 3 is a specific embodiment of the utility model.This embodiment is one: use output-current rating/power to be: the conventional CT power taking of 5A/30VA; The power output of 10.2W can both be provided within 1% ~ 150% circuit rated current scope; Branch+24V/0.1A ,+12V/0.4A, the electric supply installation that+5V/0.6A three tunnel isolates output.Its Vu1, Vu2, Vo1 are respectively: 250V, 300V, 320V.

Fig. 3 divides by the functional block of Fig. 1, and wherein CT is that 1 output-current rating/rated power is the conventional CT of 5A/30VA; The input peak voltage suppresses circuit 12 and is made up of 1 MYG14G361 type Zinc-oxide piezoresistor MOV2; First bridge rectifier 2 is full bridge rectifiers that the single-phase rectification bridge BD1 of 1 15A/600V forms; The residual current switch 3 of releasing is made up of the metal-oxide-semiconductor Q1 of 1 20A/500V; Diode 4 is general-purpose diode D1 of 1 5A/600V; The π type filter circuit that LC filter circuit 5 is made up of E6, L1, C8; Input voltage sample circuit 6 is resistance pressure-dividing networks of R6, R9, C6, D3 composition, is used for the output voltage of LC filter circuit 5 is sampled.

The average output voltage of the LC filter circuit 5 of this embodiment is about 310V; Press the 10.2W power output of matching requirements; Only need 40mA (having considered the factor of DC/DC conversion efficiency) from the average current of CT power taking; The rated current of the device that switch 3 diodes 4 are selected but first bridge rectifier 2 and residual current are released is much larger than this, and reason is to consider that electric supply installation must can sustain the short-circuit impact electric current of the moment of the short trouble generation that high-tension line possibly occur.

The bias supply that bias supply 7 is made up of DW1, E1, C7, R6, D1, RW1, E3, D1a among Fig. 3, it forms 10 power supplies of circuit 8 return difference comparison circuits 9 drive circuits for the element circuit reference voltage.When device has just powered on; The also not output of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11; Bias supply 7 is through RW1, D1, the E3 output power taking from LC filter circuit 5; And electrical power storage in E3, when isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11+24V export just often, D1a and D1 constitute " or " concern circuit select automatically+24V supplies power to bias supply 7; Design is the loss of RW1 can significantly reduce normally to move the time like this, thereby has improved the efficient of device.R6 and voltage stabilizing didoe become galvanic current to the output voltage of bias supply 7 and press to reference voltage formation circuit 8 return difference comparison circuits 9 drive circuits 10.

Reference voltage forms the reference voltage formation circuit that circuit 8 is R8, R13, C5 composition among Fig. 3; The ratio of regulating R8 and R13 can obtain the reference voltage level of needs; Reference voltage is delivered to 2 pin (negative input end of amplifier) of the amplifier U1A in the return difference comparison circuit 9; Return difference comparison circuit 9 is the return difference comparator circuits by amplifier U1A, D2, R5; Vu2, the Vo1 of the ratio handle assembly through regulating R8, R13, R5 are made as 300V, 320V respectively; U1A output high level drives the residual currents switch 3 of releasing through drive circuit 10 and connects when LC filter circuit 5 output voltages reach 320V, and the residual current switch 3 of releasing is connected back LC filter circuit 5 voltages and begun to descend, and 9 outputs of return difference comparison circuit transfer low level to by high level when dropping to 300V; The residual current switch 3 of releasing is turned off, and the residual current switch 3 of releasing closes LC filter circuit 5 voltages of having no progeny and begins to rise.The release totem pillar drive circuit of switch 3 of the metal-oxide-semiconductor residual current that drive circuit 10 is made up of triode Q2, Q3, resistance R 3, R12, voltage stabilizing didoe DW2, driving force is strong, and the switch MOS pipe guarantees the capability of fast response that the CT power taking is regulated apace.

Interchange input protection circuit 13 power-supply filters 14 second bridge rectifiers 15 among Fig. 3 are formed the compatible input channel of additional AC and DC of electric supply installations, can with CT power taking access device simultaneously, wherein any one has electricity, electric supply installation can be worked.Exchange input protection circuit 13 by the input protection element circuit that protective tube FS1, Zinc-oxide piezoresistor MOV1, negative temperature coefficient resister NTC1 form, have functions such as overcurrent protection, peak voltage inhibition, surge current inhibition; Power-supply filter 14 is X capacitor C X1, Y capacitor C Y1, CY2, the power-supply filter that resistance R 1, R2, common mode filtering inductance L C1 form; The full bridge rectifier that second bridge rectifier 15 is made up of 1A/600V single-phase rectification bridge integrated circuit BD2.

Isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 among Fig. 3 is that a single-chip switching power supply integrated circuit TNY278P with Power Integration company (i.e. U1a among the figure) is the isolated form HF switch pulse-width regulated formula DC/DC voltage-stabilized power supply circuit of the flyback topological structure of core; Have+24V/0.1A; + 12V/0.4A ,+5V/0.6A three tunnel isolates output voltage.Vu1 through the R1a handle assembly is set to 250V; When the output voltage of LC filter circuit 5 reaches 250V; Isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 begins to start, and each road output is through setting up burning voltage separately behind the soft start; Diode D6a, resistance R W2a, RW3a, capacitor C 7a, TVS pipe DZ1a form the absorption circuit, absorb the due to voltage spikes that transformer T1a leakage inductance produces; Optocoupler op1a, capacitor C 9a, C8a, resistance R 4a, R5a, voltage stabilizing didoe DW1a form feedback circuit, with the output voltage on+this road of 12V/0.4A as the FEEDBACK CONTROL target; Transformer T1a plays energy storage, isolation and three effects of transformation; Diode D4a, electric capacity E4a, E7a, the current rectifying and wave filtering circuit of this road output of inductance L 2a composition+12V/0.4A; Diode D3a, electric capacity E1a, E8a, the current rectifying and wave filtering circuit of this road output of inductance L 1a composition+5V/0.6A; The current rectifying and wave filtering circuit of diode D2a, electric capacity E3a, this road output of composition+24V/0.1A.

Be the practical implementation method of patent art one case more than, but patent protection is not limited thereto.The residual current switch 3 of releasing also can be selected devices such as triode, controllable silicon, IGBT for use; The release position of switch 3 of residual current also can be placed on after the CT, and to suppress circuit 12 parallelly connected with the input peak voltage; Vu1, Vu2, Vo1 also can be set to other value as required; Isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit 11 also can adopt the high frequency switch power of other topological structure; Its output also is not limited to three the tunnel; Also be not limited to case+24V/0.1A ,+12V/0.4A, the voltage/current of+5V/0.6A; Also be not limited to use the TNY278P integrated circuit, can design according to actual needs; The input peak voltage suppresses circuit 12 and also can select for use peak voltages such as TVS, gas discharge tube to suppress the protection device; The power output of device also is not limited to 10.2W, and CT also is not limited in the case selected, can be according to actual conditions type selecting, design.

The above be the utility model preferred embodiment, it does not constitute the restriction to the utility model protection range, so long as realize that with essentially identical means the purpose of the utility model all should belong to the protection range of the utility model.

Claims

1. current transformer power supply device is characterized in that: comprise that release switch (3), diode (4), LC filter circuit (5), input voltage sample circuit (6), reference voltage of one or more current transformer CT (1), first bridge rectifier (2), residual current forms circuit (8), return difference comparison circuit (9), drive circuit (10), isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11) and input peak voltage and suppress circuit (12); Wherein, High-tension current loop single line passes CT (1); The output of CT (1) is connected with the input of first bridge rectifier (2); The input of LC filter circuit (5) is connected with the output of first bridge rectifier (2), and the output of LC filter circuit (5) is connected with the input of isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11); The residual current switch (3) of releasing is connected between first bridge rectifier (2) and the LC filter circuit (5); Input voltage sample circuit (6) is connected between LC filter circuit (5) and the isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11); The output of input voltage sample circuit (6) is connected with return difference comparison circuit (9); Return difference comparison circuit (9) also forms circuit (8) with reference voltage simultaneously and is connected; Diode (4) is connected on residual current and releases on the circuit between switch (3) and the LC filter circuit (5), and the input peak voltage suppresses circuit (12) cross-over connection in the two ends of the second siding ring of CT (1).

2. current transformer power supply device according to claim 1 is characterized in that: isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11) is for adopting the DC/DC circuit of high frequency switch power technology.

3. current transformer power supply device according to claim 1 is characterized in that: the residual current switch (3) of releasing is connected across on the output of secondary side output winding of current transformer (CT) (1) or is connected across on the output of first bridge rectifier (2).

4. current transformer power supply device according to claim 1 is characterized in that: residual current is released switch (3) for adopting the electronic switch of devices formations such as MOSFET, IGBT, triode, controllable silicon, solid-state relay.

5. current transformer power supply device according to claim 1 is characterized in that: also comprise the drive circuit (10) that signal that return difference comparison circuit (9) is sent amplifies.

6. current transformer power supply device according to claim 1 is characterized in that: also comprise be arranged between LC filter circuit (5) and the isolated form HF switch pulse-width modulation DC/DC conversion multichannel output voltage-stabilized power supply circuit (11), form the bias supply (7) that circuit (8), return difference comparison circuit (9) and drive circuit (10) are supplied power for reference voltage.

7. current transformer power supply device according to claim 1 is characterized in that: also be included as interchange input protection circuit (13), power-supply filter (14), second bridge rectifier (15) that electric supply installation provides the compatible power supply input channel of extra AC and DC.