CN204068693U - A kind of high step-down DC/DC converter based on Sepic circuit - Google Patents

A kind of high step-down DC/DC converter based on Sepic circuit Download PDF

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Publication number
CN204068693U
CN204068693U CN201420557566.XU CN201420557566U CN204068693U CN 204068693 U CN204068693 U CN 204068693U CN 201420557566 U CN201420557566 U CN 201420557566U CN 204068693 U CN204068693 U CN 204068693U
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China
Prior art keywords
electric capacity
inductance
power switch
filter capacitor
high step
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Expired - Fee Related
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CN201420557566.XU
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Chinese (zh)
Inventor
邾玢鑫
任路路
潘海龙
黄悦华
刘义平
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China Three Gorges University CTGU
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China Three Gorges University CTGU
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Abstract

Based on a high step-down DC/DC converter for Sepic circuit, comprise power switch S 1, output filter capacitor C 0, electric capacity C 1, electric capacity C 2, inductance L 1, inductance L 2, output filter capacitor C 0one end connect input DC power V inpositive pole, switching device one end; Output filter capacitor C 0the other end connect electric capacity C 1one end, inductance L 1one end; Inductance L 1the other end connect power switch S 1drain electrode, electric capacity C 2one end; Electric capacity C 2the other end connecting valve device other end, inductance L 2one end; Electric capacity C 1the other end, power switch S 1source electrode and inductance L 2the other end connects input DC power V innegative pole; Power switch S 1grid connection control device.A kind of high step-down DC/DC converter based on Sepic circuit of the utility model, solves existing converter and there is the problems such as energy conversion efficiency reduces, switching device is too much.

Description

A kind of high step-down DC/DC converter based on Sepic circuit
Technical field
The utility model relates to DC/DC power supply, particularly a kind of high step-down DC/DC converter based on Sepic circuit.
Background technology
In prior art, basic Sepic circuit, as shown in Figure of description Fig. 1.It comprises two inductance L 1, L2, a power switch tube S 1, output diode D1.Wherein, the positive pole of the input termination input power Vin of first inductance L 1, one end of output termination first electric capacity C1 of first inductance L 1 and the drain electrode (for metal-oxide-semiconductor) of power switch tube S 1, the anode of another termination output diode D1 of first electric capacity C1 and the upper end of second inductance L 2, the negative electrode of output diode D1 connects the positive pole of output filter capacitor C0.The negative pole of the source electrode of power switch tube S 1, the lower end of second inductance L 2 and output filter capacitor C0 is all connected with the negative pole of input power Vin.This Sepic circuit step-down ability is lower, thus when completing high step-down task and BUCK circuit similar, duty ratio all works in very little state, so current ripples is large, filter volume is large, loss is also larger.Be difficult to be competent in the larger occasion of some input and output voltages difference, as: be DC/DC converter, electric automobile battery charger etc. that CPU powers in computer.In recent years, in succession occurring that some have the circuit topology of high step-down ability, mainly contained three kinds: the first is by means of transformer, in the middle of original DC/DC converter, added a transformer, having realized the object of high gain boost by changing transformer voltage ratio.But now, the conversion process of electric energy, in fact by original DC/DC, becomes: DC/AC/AC/DC, and the energy conversion efficiency of whole system reduces.The second utilizes the method for switching capacity to realize high gain boost, but switching device needed for this kind of scheme too much, control complicated, be thus also of little use.The third utilizes coupling inductance to realize high step-down, but the use of coupling inductance, switching device voltage stress can be caused equally too high, and can the impacts such as electromagnetic interference be brought, cause converter working loss larger.
Summary of the invention
For solving the problems of the technologies described above, the utility model provides a kind of high step-down DC/DC converter based on Sepic circuit, solves existing converter and there is the problems such as energy conversion efficiency reduces, switching device is too much.
The technical scheme that the utility model is taked is: a kind of high step-down DC/DC converter based on Sepic circuit, comprises power switch S 1, output filter capacitor C 0, electric capacity C 1, electric capacity C 2, inductance L 1, inductance L 2, output filter capacitor C 0one end connect input DC power V inpositive pole, switching device one end; Output filter capacitor C 0the other end connect electric capacity C 1one end, inductance L 1one end; Inductance L 1the other end connect power switch S 1drain electrode, electric capacity C 2one end; Electric capacity C 2the other end connecting valve device other end, inductance L 2one end; Electric capacity C 1the other end, power switch S 1source electrode and inductance L 2the other end connects input DC power V innegative pole; Power switch S 1grid connection control device.
Described power switch S 1for MOSFET pipe or IGBT.
Described switching device is diode D 1, diode D 1anode connect electric capacity C 2the other end, diode D 1negative electrode connect output filter capacitor C 0one end.
Described switching device is that the grid of MOSFET pipe or IGBT, MOSFET pipe or IGBT connects a controller.
A kind of high step-down DC/DC converter based on Sepic circuit of the utility model, beneficial effect is as follows:
1), there is high step-down ability, and not containing transformer in circuit.Circuit structure is simple, and output performance is good, and cost is low, and volume is little.
2), compared to buck circuit, have higher step-down ratio, when realizing high step-down, duty ratio is without the need to working in limiting condition, and input and output current ripples is little, has filter volume little, the advantage that power density is high.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of Sepic described in background technology.
Fig. 2 is the utility model height step-down DC/DC converter circuit figure (power switch S 1for MOSFET pipe).
Fig. 3 is the simulation waveform figure of Sepic circuit.
Fig. 4 is the simulation waveform figure of the utility model height step-down DC/DC converter.
Embodiment
As shown in Figure 2, a kind of high step-down DC/DC converter based on Sepic circuit, comprises power switch S 1, output filter capacitor C 0, electric capacity C 1, electric capacity C 2, inductance L 1, inductance L 2.This high step-down DC/DC converter is used for direct-current input power supplying terminal voltage V inoutput voltage V after carrying out step-down out.Output filter capacitor C 0one end connect input DC power V inpositive pole, switching device one end.Output filter capacitor C 0the other end connect electric capacity C 1one end, inductance L 1one end.
Inductance L 1the other end connect power switch S 1drain electrode, electric capacity C 2one end.Electric capacity C 2the other end connecting valve device other end, inductance L 2one end.Electric capacity C 1the other end, power switch S 1source electrode and inductance L 2the other end connects input DC power V innegative pole.Power switch S 1grid connection control device.Output filter capacitor C 0one end, output filter capacitor C 0the other end form output voltage V outpositive pole, negative pole.
Described power switch S 1adopt MOSFET pipe or IGBT.
Described switching device is diode D 1, diode D 1anode connect electric capacity C 2the other end, diode D 1negative electrode connect output filter capacitor C 0one end.Or described switching device is that the grid of MOSFET pipe or IGBT, MOSFET pipe or IGBT connects an independently controller.The preferred switching device of the utility model is diode D 1.
The input of a kind of high step-down DC/DC converter based on Sepic circuit of the utility model can connect PFC rectification and export, and output voltage is controlled low-voltage DC.
As shown in Figure 2, because of electric capacity C owith electric capacity C 1after series connection and at input DC power two ends, therefore electric capacity C oand electric capacity C 1terminal voltage sum is equal with input DC power voltage magnitude, by control capacitance C 1the size of terminal voltage, can realize output voltage V outcontrol.According to the difference of power switch state, circuit can be divided into 2 kinds of operating states:
1), controller controls power switch S 1conducting, input DC power is by electric capacity C 1for output filter capacitor C oand load supplying, electric capacity C 1by power switch S 1for inductance L 1charging, electric capacity C 2by power switch S 1for inductance L 2charging, diode D 1be in off state.
2), controller controls power switch S 1turn off, input DC power is by electric capacity C 1for output filter capacitor C oand load supplying, electric capacity C 1pass through inductance L 1, diode D 1and input DC power is electric capacity C 2charging, portion of energy also feeds back in input DC power simultaneously, now inductance L 2by diode D 1energy back is fed back in DC power supply.
Known by circuit working state, in practical work process, output voltage V outfor input DC power amplitude and electric capacity C 1the difference of terminal voltage amplitude, filter capacitor C ocan omit, the cost of circuit can be reduced further.Power electronics specialty simulation software PSIM is utilized to emulate present embodiment and traditional Sepic circuit; Emulation is divided into two groups, and first group adopts present embodiment to realize 400V to 40V step-down, power output 400W, and second group adopts traditional Sepic circuit realiration 400V to 40V step-down, power output 400W.Outside two groups of emulation experiment removing circuit structure differences, selected experiment apparatus is completely the same with other emulation setting model, the simulation experiment result respectively as shown in Figure 3, Figure 4, can find out that the step-down ability of a kind of high step-down DC/DC converter based on Sepic circuit of the utility model is strong.

Claims (4)

1., based on a high step-down DC/DC converter for Sepic circuit, comprise power switch S 1, output filter capacitor C 0, electric capacity C 1, electric capacity C 2, inductance L 1, inductance L 2, it is characterized in that, output filter capacitor C 0one end connect input DC power V inpositive pole, switching device one end; Output filter capacitor C 0the other end connect electric capacity C 1one end, inductance L 1one end; Inductance L 1the other end connect power switch S 1drain electrode, electric capacity C 2one end; Electric capacity C 2the other end connecting valve device other end, inductance L 2one end; Electric capacity C 1the other end, power switch S 1source electrode and inductance L 2the other end connects input DC power V innegative pole;
Power switch S 1grid connection control device.
2. a kind of high step-down DC/DC converter based on Sepic circuit according to claim 1, is characterized in that, described power switch S 1for MOSFET pipe or IGBT.
3. a kind of high step-down DC/DC converter based on Sepic circuit according to claim 1, it is characterized in that, described switching device is diode D 1, diode D 1anode connect electric capacity C 2the other end, diode D 1negative electrode connect output filter capacitor C 0one end.
4. a kind of high step-down DC/DC converter based on Sepic circuit according to claim 1, is characterized in that, described switching device is that the grid of MOSFET pipe or IGBT, MOSFET pipe or IGBT connects a controller.
CN201420557566.XU 2014-09-26 2014-09-26 A kind of high step-down DC/DC converter based on Sepic circuit Expired - Fee Related CN204068693U (en)

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CN201420557566.XU CN204068693U (en) 2014-09-26 2014-09-26 A kind of high step-down DC/DC converter based on Sepic circuit

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Application Number Priority Date Filing Date Title
CN201420557566.XU CN204068693U (en) 2014-09-26 2014-09-26 A kind of high step-down DC/DC converter based on Sepic circuit

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116799915A (en) * 2023-06-29 2023-09-22 航天锂电科技(江苏)有限公司 Voltage reduction equalization circuit of lithium battery pack and control method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116799915A (en) * 2023-06-29 2023-09-22 航天锂电科技(江苏)有限公司 Voltage reduction equalization circuit of lithium battery pack and control method thereof
CN116799915B (en) * 2023-06-29 2023-12-29 航天锂电科技(江苏)有限公司 Voltage reduction equalization circuit of lithium battery pack and control method thereof

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20141231

Termination date: 20150926

EXPY Termination of patent right or utility model