CN2735658Y

CN2735658Y - Optical fiber isolating driving protection circuit for power switching device

Info

Publication number: CN2735658Y
Application number: CN 200420062534
Authority: CN
Inventors: 何礼高; 肖庆恩; 陈扬飞; 张工厂
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-07-08
Filing date: 2004-07-08
Publication date: 2005-10-19
Anticipated expiration: 2014-07-08

Abstract

The utility model relates to an optical fiber isolating driving protection circuit for power switching device, which is applied to the high voltage occasion. The utility model is safety, reliability, simplicity, and cheap, Using ordinary plastic optical fiber realizes that the controlling circuit is isolated from the horsepower main circuit and the synthesis and optimum design of the photoelectric conversion, the signal amplification, the driving pre-processor, the output, the overcurrent checking, and the failure cut-out unit, and the photoelectric conversion circuit and the signal amplifying circuit are directly designed in the driving holding circuit. The optical fiber is directly inserted, which can make the driving holding circuit work in normal instead that the actuating signal is processed in advance through the optical fiber transceiver unitized by the special purpose chip. Low cost surface attaching discrete device is entirely adopted, and the enclosure is in modularization. The novel signal amplifier stage and prestage are all provided with transistor constant-current source circuit and overcome the disadvantages of the Long turn-off time of the multiple-unit tube in the signal amplifier.

Description

Power Switcher Ware And Optical Fibre Isolation Driving Protection Circuit

Technical field the utility model relates to a kind of Drive Protecting Circuit of electric and electronic power switching device, especially can be applicable to the Power Switcher Ware And Optical Fibre Isolation Driving Protection Circuit of high voltage power main circuit.

Background technology is in the driving of electric and electronic power switching device, the isolation of drive signal is extremely important, it not still control circuit on being electrically connected, keep apart a kind of measure of disturbing, make control stabilization reducing with the big high-tension power main circuit of electric current, the still indispensable key technology of upper and lower bridge arm power device operate as normal in the high-power bridge conversion circuit.Isolation method commonly used at present has photoelectric coupler isolation, pulse transformer isolation etc.Along with power electronics multi-level inverse conversion technology in the application aspect high voltage direct current power transmission and distribution and the super high power frequency control, the operating voltage of power main circuit is more and more higher, generally between 6600V to 10KV, utilize photoelectrical coupler or transformer to carry out Signal Spacing again this moment and can't satisfy requirement of withstand voltage.The insulation property of optical fiber are fabulous, carry out the drive signal isolation with optical fiber the fiber-optic signal path is set with can growing distance, therefore can be used for transmitting under the high voltage operation environment drive signal.And optical fiber has many advantages: bandwidth is big, and is in light weight, noiseless between each road optical fiber, is not subjected to the interference of electromagnetic induction, and high-temperature-resistant and anti-corrosion etc. are in recent years by being applied in power electronics high pressure occasion.But the optical fiber isolation technology that is used for the electric and electronic power converting means at present is to use for reference to introduce from the optical fiber communication technology of communication field, mostly adopt the optical-fibre communications special chip to form fiber optical transceiver, HFBR-1521 and HFBR-2521 as U.S. Agilent company, because of its input and output are TTL or CMOS logic levels commonly used in the communication, so must drive the drive level that special chip combines the gate pole that is converted to power device with other power device, could form the optical fiber isolated drive circuit, make the drive circuit complexity like this, cost increases.

This novel purpose of summary of the invention provides a kind of high voltage occasion that is applied in, safe and reliable, simple inexpensive electric and electronic power switching device optical fiber isolation drive protective circuit.

This novel technical solution is: with opto-electronic conversion, signal amplify, drive preposition, drive output, over-current detection and fault and turn-off the element circuit Synthetical Optimization; photoelectric switching circuit and signal amplification circuit directly design in Drive Protecting Circuit; the direct insertion of optical fiber can make the Drive Protecting Circuit operate as normal, between need not handle drive signal through the fiber optic receiver that special chip is formed in advance.All adopt surface mount discrete device cheaply, the modularization encapsulation.

This novel technical characterictic is: the signal amplifier that the NPN-PNP multiple tube of high-gain and transistor constant current source are formed amplifies the small-signal that PIN photodiode received; The driving front end circuit that single tube amplifier and transistor constant current source are formed is once more with the amplitude and the power amplification of drive signal, with reliable and stable ground of controlling and driving output circuit output drive signal.

Because the gain of NPN-PNP multiple tube is very high,, use common highlighted LED and general plastic fiber can reliably transmit drive signal so this novel input sensitivity is high.Again because all gone here and there the constant-current transistor source circuit in amplified signal level and prestage, so this novel turn-off time that has overcome the shortcoming of transistor multiple tube turn-off time length and reduced prestage, make the dynamic response of drive circuit can reach 60KHz, the edge postpones＜2 μ S before and after the signal.

The beneficial effects of the utility model are: control signal gets final product the reliable and stable device for power switching that is sent to by common plastics optical fiber, makes the electrical isolation of control circuit and power main circuit can reach 6600V to 10KV, and simple in structure, with low cost.

Description of drawings Fig. 1 is circuit theory diagrams;

Fig. 2 is the input and output oscillograms;

Fig. 3 is the overcurrent protection movement oscillogram.

This novel optical fiber of embodiment isolation drive protective circuit comprises the photoelectric switching circuit that D1, R1 form; the signal amplification circuit that Q1, Q2, Q3, DW2, R2, R16 and R17 form; the driving front end circuit that R3, R4, R5, DW1, Q4 and Q5 form; the driving output circuit that R13, R14, Q8 and Q9 form; the over-current detection circuit that R7, R8, R9, R11, DW3, CI and Q6 form; the slow breaking circuit of fault that R12, R10, D2, C2 and Q7 form, and the fault-signal output circuit of R15 and D3 composition.

Below in conjunction with Fig. 1, describe the course of work of this novel optical fiber isolation drive protective circuit in detail.

Opening process: when the driving light signal transmits from optical fiber, photodiode D1 is because optoelectronic induction and reverse-conducting, its reverse current is after the multiple tube of Q1 and Q2 composition amplifies, converting voltage signal to by R3, R4 send the Q5 preamplifier further to be enlarged into the voltage signal of certain amplitude, make Q9 conducting output high level drive signal, its signal voltage amplitude reaches the supply voltage of drive circuit, and this is novel to be+15V to be fit to drive IGBT, MOSFET constant power device.

Turn off process: no light signal is promptly represented to turn-off in the optical fiber, photodiode D1 oppositely ends, the multiple tube and the Q5 preamplifier of Q1 and Q2 composition all end thus, then conducting of Q6 in the over-current detection circuit, mask the slow breaking circuit of fault of over-current detection function and back, the Q9 that drives output circuit ends and the Q8 conducting, sends the reverse shutoff voltage of power device.The constant-current source circuit that Q3, DW2 and R16 form has limited the saturation current of multiple tube Q2, has significantly reduced its turn-off delay time; The constant-current source circuit that Q4, DW1 and R5 form has limited the saturation current of pre-amplification circuit Q5, quickens its turn off process.

The overcurrent protection turn off process: during the power device normally, the Q6 in the over-current detection circuit ends, and starts the slow breaking circuit of fault of over-current detection function and back.As from the saturated tube voltage drop of the detected power device of R11 in normal value, DW3 is not breakdown oppositely to be ended, Q7 ends, protection is turn-offed and is failure to actuate.If be short-circuited during the power device conducting, power device will bear overcurrent and withdraw from saturatedly, and its tube voltage drop UCE rises much suddenly, be imported into by R11 DW3 is punctured, the Q7 conducting, C2 is by R12 and Q7 discharge, and D2 negative terminal current potential progressively descends, and drives the Q9 of output circuit and the base potential of Q8 and also progressively descends, therefore Q9 ends and the Q8 conducting, form and turn-off action slowly, to reduce the adverse effect of turn-offing fast under the big electric current, the safety of guaranteed output device.Meanwhile, D3 externally exports fault-signal by R12, Q7 forward conduction and luminous.

Claims

1, a kind of Power Switcher Ware And Optical Fibre Isolation Driving Protection Circuit; by opto-electronic conversion, signal amplify, drive preposition, drive output, over-current detection and fault and turn-off element circuit and be linked in sequence and form; it is characterized in that: photoelectric switching circuit and signal amplification circuit directly design in Drive Protecting Circuit; drive signal sends Drive Protecting Circuit to by optical fiber, and the detected over current fault signal of Drive Protecting Circuit externally sends by optical fiber.

2, Power Switcher Ware And Optical Fibre Isolation Driving Protection Circuit according to claim 1 is characterized in that: the photoelectric switching circuit back connects the signal amplification circuit that a multiple tube is formed, and the signal amplification circuit back connects the driving front end circuit.

3, Power Switcher Ware And Optical Fibre Isolation Driving Protection Circuit according to claim 1 is characterized in that: all going here and there in the signal amplification circuit that multiple tube is formed and in the driving front end circuit of back has the constant-current transistor source circuit.