CN2458816Y - Full-voltage series independent-excited pure DC/DC converter - Google Patents

Abstract

The utility model belongs to a DC/DC transformer, which is composed of a main conversion circuit and an auxiliary excitation circuit. The utility model is characterized in that the main conversion circuit mainly comprises one or a plurality of series connection or parallel connection double half-bridge circuits, each of the double half-bridge circuits is composed of a switch tube Q1, a switch tube Q2, a transformer T1, a capacitor C3 and a capacitor C4, the auxiliary excitation circuit is composed of a battery unit BT1 and a PG-8 modular circuit with a TL-494 voltage stabilizing integrated block, grid electrodes of the switch tubes of the half-bridge circuits are controlled by the PG-8 modular circuit. The utility model having the advantages of compact circuit and high efficiency is suitable for any voltage levels.

Description

The pure DC/DC converter of full voltage series independent-excited

The utility model relates to the supply convertor technical field, especially a kind of DC/DC converter.

The DC/DC converter mainly contains two kinds both at home and abroad at present: auto-excitation type and independent-excited.The AC/DC converter that Japan major company of a few family produces mostly adopts earlier and gives main DC/DC converter power supply alternating current by the transformer step-down rectifier, and main DC/DC converter could be worked.The like product of more domestic manufacturer production is also mostly continued to use this method.But in pure DC/DC converter owing to there is not alternating current can supply the transformation rectification, thereby the design of the accessory power supply of independent-excited DC/DC converter just very difficult, when particularly main power voltage is above 500V.General producer mostly utilizes the high-power resistance step-down at low-voltage area, powers to main DC/DC converter with the way of voltage-stabiliser tube voltage stabilizing then.The method of auxiliary single tube DC/DC converter to main DC/DC converter power supply that adopt also arranged in addition.Although the each have their own pluses and minuses of this dual mode, because main power voltage is low, and ohmically power consumption is also little, auxiliary single tube DC/DC converter still can be endured in the past at low-voltage area, and this contradiction is not outstanding.In case when main power voltage surpasses 500V, obviously be unfavorable with the resistance step-down or with the auxiliary DC/DC of single tube again.So the producer of the DC/DC converter that more domestic production 500V are above mostly adopts auto-excitation type, the DC/DC converter of this auto-excitation type is in order to obtain stable low-voltage direct, earlier high voltage direct current is become low-voltage direct by self-maintained circuit, obtain unsettled low-voltage direct after the rectification, again by transferring stretch circuit or chopper circuit, at last could obtain stable low-voltage direct, alternation is straight so again and again, the straight change handed over, not only level is many, complex circuit, the failure rate height, whole efficient is also had a greatly reduced quality.

At above-mentioned situation, the utility model proposes the pure DC/DC converter of a kind of full voltage independent-excited, have simple in circuits, the characteristics that efficient is high.

The pure DC/DC converter of the utility model full voltage series independent-excited, change circuit and the auxiliary excitation circuit is formed by main transformer, it is characterized in that, main transformer changes two half-bridge circuits that circuit mainly comprises one or more serial or parallel connections, two half-bridge circuits are made up of switching tube Q1, Q2 and transformer T1, capacitor C3, C4, auxiliary excitation electric routing battery group BT1, be that the PG-8 modular circuit of core is formed with the TL-494 integrated package of pressure-stabilizing, the switching tube grid in two half-bridge circuits is controlled by the PG-8 modular circuit.

The utility model circuit is succinct, owing to do not need multiple conversions, efficient is improved, and is applicable to the free voltage grade.

Fig. 1 is the main circuit diagram of the utility model embodiment, and Fig. 2 is the accessory power supply PG-8 module circuit diagram of the utility model embodiment.

Below in conjunction with drawings and Examples the operation principle of the present utility model and the course of work are described.When main power source get electric after, the R5 of PG-8 modular circuit, R4 just has electric current to pass through, it obtains a suitable voltage after the R3 dividing potential drop be the base stage of capacitor C 3 through Q2 (npn), emitter-base bandgap grading is to the ground charging, Q2 obtains enough inclined to one side saturation conductions, after the Q2 conducting, the base stage of Q1 (pnp) becomes also saturation conduction of electronegative potential by high potential, so pass through plug P1 to the Q2 emitter by battery pack BT1 (forming by 3 joint 3.6V Ni-Cr batteries among the embodiment), collector electrode passes through diode D3 again to module for power supply, with integrated circuit TL-494 is that the module of core gets electric work, whole DC/DC circuit is also started working, output is stably exported the 24V DC power supply, meanwhile the charging current on the C1 stops gradually, Q2 loses positively biased and withdraws from the saturation region, become conducting into ending, the extremely basic current potential of Q1 is also uprised by low, and the change conducting is cut-off state, and battery pack BT1 withdraws from power supply state.Module is by 7815 power supplies of three-terminal voltage-stabilizing integrated package after the DC/DC converter operate as normal, and meanwhile to battery pack BT1 charging, whole starting process also comes to an end the 15V power supply by resistance R 1, light-emitting diode D2.Because when the DC/DC converter is used as the Underground Locomotive Carrier power supply, electric locomotive has mobility, main power source all may disconnect at any time and be closed, designed the discharge loop of capacitor C 1 again for this reason, when the moment capacitor C 1 that power supply disconnects is discharged rapidly by resistance R 3, diode D4, circuit repeats above-mentioned start-up course again after the main power source closure, and entire circuit is operate as normal again.The voltage height that the utility model DC/DC converter is suitable for only with in the circuit has what half-bridge circuits and they whether connection in series-parallel is relevant, and with to start power circuit irrelevant.Embodiment accessory power supply reactive loss only is (24-15) V * 100mA, approximates 1W, is equivalent to part to tens/one of other circuit.The characteristics of this circuit are not only on start-up circuit, main DC/DC translation circuit also has innovation: in order to increase reliability and the power that product uses under high voltage, single half-bridge circuit that the utility model is changed in the past is two half-bridge circuits, and upward (in like manner also can be designed to three half-bridges the primary coil of each half-bridge and around transformer T1, four half-bridges are to be used on the higher voltage), can definitely guarantee the unanimity of two winding inductance quantities so on the one hand, can guarantee also that on the other hand high-power switch tube goes out dynamic balance, so no matter power supply is in (zero load under what state, fully loaded, overload even short circuit) midpoint potential of half-bridge remains that constant (parallel connection is 1/2nd, series connection is 1/4th), so both reduced parameter request, guaranteed its normal use again high-power switch tube.For above-mentioned reasons, the utility model can be made the free voltage grade (embodiment is 400～1000V).Comprise soft start, voltage stabilizing and bridge-type exciting circuit among the embodiment, also comprised protective circuits such as zero load, overload, short circuit simultaneously.

Claims (2)

1, the pure DC/DC converter of full voltage series independent-excited, change circuit and the auxiliary excitation circuit is formed by main transformer, it is characterized in that, main transformer changes two half-bridge circuits that circuit mainly comprises one or more serial or parallel connections, two half-bridge circuits are made up of switching tube Q1, Q2 and transformer T1, capacitor C3, C4, auxiliary excitation electric routing battery group BT1, be that the PG-8 modular circuit of core is formed with the TL-494 integrated package of pressure-stabilizing, the switching tube grid in two half-bridge circuits is controlled by the PG-8 modular circuit.

2, the pure DC/DC converter of full voltage according to claim 1 series independent-excited is characterized in that, main transformer changes the primary coil of each half-bridge circuit in the circuit and on transformer T1.

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