CN105515367A - High-step-down DC/DC converter based on a Sepic circuit - Google Patents
High-step-down DC/DC converter based on a Sepic circuit Download PDFInfo
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- CN105515367A CN105515367A CN201410499910.9A CN201410499910A CN105515367A CN 105515367 A CN105515367 A CN 105515367A CN 201410499910 A CN201410499910 A CN 201410499910A CN 105515367 A CN105515367 A CN 105515367A
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- electric capacity
- inductance
- power switch
- filter capacitor
- output filter
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Abstract
A high-step-down DC/DC converter based on a Sepic circuit comprises a power switch S1, an output filter capacitor C0, a capacitor C1, a capacitor C2, an inductor L1 and an inductor L2. One end of the output filter capacitor C0 is connected with the anode of an input direct-current power supply Vin and one end of a switching device. The other end of the output filter capacitor C0 is connected with one end of the capacitor C1 and one end of the inductor L1. The other end of the inductor L1 is connected with the drain of the power switch S1 and one end of the capacitor C2. The other end of the capacitor C2 is connected with the other end of the switching device and one end of the inductor L2. The other end of the capacitor C1, the source of the power switch S1 and the other end of the inductor L2 are connected with the cathode of the input direct-current power supply Vin. The gate of the power switch S1 is connected with a controller. By adopting the high-step-down DC/DC converter based on a Sepic circuit, the problems of the existing converter, such as low energy conversion efficiency and too many switching devices, are solved.
Description
Technical field
The present invention 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 invention provides a kind of high step-down DC/DC converter based on Sepic circuit, solving existing converter and there is the problems such as energy conversion efficiency reduces, switching device is too much.
The technical scheme that the present invention takes 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 present invention, 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 height step-down DC/DC converter circuit figure (power switch S of the present invention
1for MOSFET pipe).
Fig. 3 is the simulation waveform figure of Sepic circuit.
Fig. 4 is the simulation waveform figure of height step-down DC/DC converter of the present invention.
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 present invention is diode D
1.
The input of a kind of high step-down DC/DC converter based on Sepic circuit of the present invention 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 present invention 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410499910.9A CN105515367A (en) | 2014-09-26 | 2014-09-26 | High-step-down DC/DC converter based on a Sepic circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410499910.9A CN105515367A (en) | 2014-09-26 | 2014-09-26 | High-step-down DC/DC converter based on a Sepic circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105515367A true CN105515367A (en) | 2016-04-20 |
Family
ID=55723106
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410499910.9A Pending CN105515367A (en) | 2014-09-26 | 2014-09-26 | High-step-down DC/DC converter based on a Sepic circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105515367A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110118903A (en) * | 2019-04-19 | 2019-08-13 | 清华大学 | The equivalent full power hookup of electric power electric transformer DC port and control method |
| CN110247546A (en) * | 2019-06-04 | 2019-09-17 | 苏州汇川联合动力系统有限公司 | Non-isolation type biswitch reduction voltage circuit and DC-DC converter |
-
2014
- 2014-09-26 CN CN201410499910.9A patent/CN105515367A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110118903A (en) * | 2019-04-19 | 2019-08-13 | 清华大学 | The equivalent full power hookup of electric power electric transformer DC port and control method |
| CN110247546A (en) * | 2019-06-04 | 2019-09-17 | 苏州汇川联合动力系统有限公司 | Non-isolation type biswitch reduction voltage circuit and DC-DC converter |
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| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20160420 |
|
| WD01 | Invention patent application deemed withdrawn after publication |