CN2158163Y - Self-adaptation variable-frequency two-terminal switch power supply - Google Patents

Abstract

The utility model belongs to a voltage inverter used for the illuminating of a mining stringing electric locomotive, which is composed of a bidirectional mutual inductance filter, a switching oscillation circuit and a transformer. Two switch tubes are arranged in the switching oscillation circuit in series. The switching tubes are connected with a current enlarging tube in parallel. The current winding of the transformer is two sets of windings in duplex windings. A load winding, a supply winding and a feedback winding wind on a same magnetic core from inner to exterior in sequence. Compared with traditional transistor switch powers which emulates color television switched mode, the utility model has the advantages of width electric voltage application field, large power, high efficiency and low failure rate.

Description

Self-adaptation variable-frequency two-terminal switch power supply

The utility model relates to a kind of high voltage inverter, is applicable to the illumination of mine stringing electrical locomotive.

At present, the power supply that mine stringing electrical locomotive illumination is used is generally the transistor switch power supply of SCR inverter or imitative colour TV switch power supply type, and is a kind of because volume is big, weight is big, failure rate is high is replaced by the latter day by day before these two kinds of devices.Latter's volume is little, in light weight, and Fig. 1 is its circuit theory sketch.Because power supply winding N ₁Direction of current flow be unidirectional; it makes the magnetic core of transformer be always operating at a side of magnetic hysteresis loop; efficient is lower; switching tube VT is at shutdown moment in addition; its collector electrode will bear the peak voltage of several times supply voltage; the RC peak voltage that must increase power consumption for the protection switch pipe absorbs circuit, so its overall efficiency is lower.This electromechanics presses the scope of application also narrow, and unit work only below 340V, if use on the 550V grade, must be connected by two-shipper, and this has just increased cost, has reduced reliability.Under the adverse circumstances of down-hole, its degree of reliability time can not be satisfactory on the other hand.

At above-mentioned defective, the Switching Power Supply that mine stringing electrical locomotive illumination that the utility model provides a kind of efficient height, the voltage scope of application is wide, power is big, reliability is higher is used.

The utility model is to realize like this.Two switching tubes of series connection in oscillating circuit, each pipe only bears 1/2nd supply voltages at work.Two switching tubes also are parallel with a pair of electric current enlarged tube, so not only can improve the power output of complete machine, have also reduced simultaneously the injury that the very high inverse peak voltage of numerical value that the switching tube shutdown moment produces may cause switching tube.The load winding of transformer portion, power supply winding and feedback winding are from inside to outside on same magnetic core.The power supply winding be two-wire and around two groups of coils, can realize easily that with a diverter switch 250V/550V two retaining switches.

Owing to adopt such scheme, every switching tube only bears 1/2nd supply voltages, and the utility model supply voltage scope of application can extend to 550V, simultaneously because power of transformer winding current direction is two-way, make magnetic core be operated in the both sides of magnetic hysteresis loop, improved efficient; Load winding, power supply winding, feedback winding are on same magnetic core; can not only realize with the same load short circuits failure of oscillation defencive function of colour TV Switching Power Supply; and can adjust the transducing number of times (change of frequency just) of unit interval in the loop automatically; to adapt to the variation of load, overall efficiency is brought up to more than 90%.On the other hand and since the switching tube parallel connection electric current enlarged tube, the shutdown moment peak voltage that it bears is much smaller, thereby has reduced failure rate, simultaneously, the also corresponding expansion of power output, and save the RC peak voltage and absorb circuit.

Fig. 1 simplifies circuit theory diagrams for imitative colour TV switch power supply type transistor switch power supply.

Fig. 2 is the circuit theory diagrams of the utility model embodiment.

The utility model is described in further detail below in conjunction with Fig. 2.

L is common mutual inductance bidirectional filter among the figure, it and capacitor C ₅, C ₆, C ₇Cooperate peak voltage and interference on the filtering electrical network, simultaneously also during filter out power work to the pollution of electrical network.The R that power end seals in ₀Be the little PTC element of numerical value, it is big that the adstante febre resistance becomes rapidly, plays overcurrent protection.C ₃, C ₄Be the electrochemical capacitor of withstand voltage more than 400V, it is a power filtering capacitor, is again switch oscillating tube VT ₁, VT ₂Charging capacitor.The high back-pressure large power triode VT of a pair of band damper diode ₃, VT ₄With VT ₁, VT ₂In parallel.C ₁, C ₂Be tank circuit inductance, R ₁, R ₂, R ₃, R ₄Be current-limiting resistance, transformer T has four windings: power supply winding N ₁, oscillatory feedback winding N ₂, N ₃With load winding N ₄Start-up course is as follows: as power supply K ₁Connect the back and pass through mutual induction filter L to C ₃, C ₄Charging is simultaneously by starting resistance R ₅Be VT ₁Base stage provides a small base stage bias current Ib ₁, through VT ₁Amplify the back and produce a bigger collector electrode stream IC ₁, the flow direction of electric current is DC power supply → VT ₁→ transformer N ₁Winding end → C of the same name ₄To ground, because N ₁, N ₂And N ₃Phase relation, this electric current will be at N ₂End of the same name produces a positive voltage and impels VT ₁Rapid saturation conduction is simultaneously at N ₃The different name end produces a negative voltage and shuts VT ₂This process can be understood as C ₄Charging process, VT ₁Saturated back IC ₁No longer increase circuit and just will reverse, at this moment N ₂End of the same name will produce a negative voltage and make VT ₁Withdraw from the saturation region and jump to cut-off region, simultaneously N ₃The different name end produces a positive voltage and makes VT ₂Jump to the saturation region by cut-off region.At this moment the sense of current is DC power supply → C ₃→ N ₁Different name end → VT ₂To ground.This process can be understood as C ₃Charging process (also can be regarded as C ₄Discharge process), VT ₁, VT ₂Alternately conducting with by (C just ₃, C ₄Charge and discharge alternately), will be at the N of transformer T ₄Winding induces a square-wave voltage than standard and powers to the load.When load is light, R ₁, R ₂Both end voltage is less than 0.7V, VT ₃And VT ₄Do not participate in work.Have only the load of working as heavier, R ₁, R ₂Terminal voltage is during greater than 0.7V, VT ₃And VT ₄Just participation work.Power supply winding N when unloaded in addition ₁The induction reactance maximum that presents, the obvious step-down of frequency of oscillation can produce clear and melodious tweeting sound to remind user's attention.Select the suitable turn ratio can guarantee that oscillatory feedback voltage keeps optimum value in the rated power scope, make VT ₁, VT ₂Reliably working.R ₅, R ₆Be both starting resistance, remove any one circuit is normally started, but when load short circuits is protected, all supply voltage will be added in C ₃Or C ₄On the some electric capacity, this might damage electric capacity (especially when 550V works), in order to prevent this from occurring, design two starting resistances simultaneously, can guarantee C under the short-circuit protection state ₃And C ₄The voltage that bears is equal substantially, and the course of work is such: load N ₄Behind the short circuit in winding, N ₂, N ₃On feedback voltage can not set up circuit failure of oscillation, at this moment R ₅, R ₆Continue to give respectively VT ₁, VT ₂Provide bias current to make VT ₁, VT ₂Weak conducting, the sense of current is DC power supply → VT ₁→ VT ₂To ground, because R ₅, R ₆All be the resistance of numerical value, so IC greater than 1 megaohm ₁, IC ₂Electric current is also little, and power consumption is very little.Because VT when the choosing pipe ₁And VT ₂The β value equal substantially, so V _Ce1With V _Ce2Substantially equal, C ₃With C ₄Terminal voltage is also equal substantially.

Owing to there is not the voltage stabilizing part, output voltage slightly changes during grid voltage change in the present embodiment, and in view of mine mostly adopts switched-mode power supply, the network pressure drop is little, so this problem is not outstanding.

Claims (2)

1, a kind of self-adapting frequency conversion two-terminal switch power supply that is applicable to that mine stringing electrical locomotive illumination is used, form by common mutual inductance bidirectional filter, switch oscillating circuit and transformer, it is characterized in that, two switching tubes of series connection in the switch oscillating circuit, two switching tubes and a pair of electric current enlarged tube are in parallel, the load winding of transformer, power supply winding, feedback winding are wound on the same magnetic core from inside to outside successively, the power supply winding be two-wire and around two groups of coils, its electric current is two-way.

2, power supply according to claim 1 is characterized in that the electric current enlarged tube adopts the high back-pressure large power triode of band damper diode.

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