DC/DC converter based on switch capacitor and resonance SEPIC circuit
阅读说明：本技术 一种基于开关电容和谐振sepic电路的dc/dc变换器 (DC/DC converter based on switch capacitor and resonance SEPIC circuit ) 是由 管乐诗 王懿杰 李方 姚婷婷 徐殿国 王卫 于 2019-09-26 设计创作，主要内容包括：本发明是一种基于开关电容和谐振SEPIC电路的DC/DC变换器。所述变换器包括前级开关电容电路和后级谐振SEPIC开关电路。所述前级开关电容电路包括四个开关管S<Sub>1</Sub>、S<Sub>2</Sub>、S<Sub>3</Sub>和S<Sub>4</Sub>、两个电容C<Sub>1</Sub>和C<Sub>2</Sub>、电感L<Sub>c</Sub>和电压源V<Sub>in</Sub>。所述后级谐振SEPIC开关电路由逆变电路、匹配网络和整流电路组成。本申请通过开关电容电路和谐振Sepic电路两级降压,实现了高降压比的DC/DC功率变换器。通过软充电的工作方式,使开关电容电路效率大幅提高,整个系统的效率也得到了提升,实现了系统的高效率。(The invention relates to a DC/DC converter based on a switch capacitor and a resonant SEPIC circuit. The converter comprises a front stage switch capacitor circuit and a rear stage resonance SEPIC switch circuit. The pre-stage switch capacitor circuit comprises four switch tubes S 1 、S 2 、S 3 And S 4 two capacitors C 1 And C 2 Inductor L c And a voltage source V in . The post-stage resonance SEPIC switch circuit consists of an inverter circuit, a matching network and a rectifying circuit. The DC/DC power converter with the high voltage reduction ratio is realized by two-stage voltage reduction of the switched capacitor circuit and the resonance Sepic circuit. Through the working mode of soft charging, the efficiency of the switched capacitor circuit is greatly improved, the efficiency of the whole system is also improved, and the high efficiency of the system is realized.)
1. A DC/DC converter based on a switch capacitor and a resonant SEPIC circuit is characterized in that: the converter comprises a front-stage switch capacitor circuit and a rear-stage resonance SEPIC switch circuit;
The pre-stage switch capacitor circuit comprises four switch tubes S1、S2、S3And S4Two capacitors C1And C2Inductor LcAnd a voltage source Vin；
The voltage source VinThe positive terminal of the switch tube S1One end of (1), a switching tube S1The other end of the switch tube S2、S3And S4In series, said capacitor C1And a switching tube S2and S3Parallel connection, inductance LcAnd a capacitor C2One end of which is connected in series with an inductor LcAnd a capacitor C2Simultaneously with the switching tube S3And S4Parallel connection, a capacitor C2Is connected with a voltage source V at the other endinThe negative terminal of (1);
the post-stage resonance SEPIC switch circuit consists of an inverter circuit, a matching network and a rectifying circuit; the inverter circuit comprises an inductor LFCapacitor CFAnd a switching tube S5(ii) a The matching network comprises a capacitor CsAnd an inductance LsThe rectifier circuit comprises an inductor LRECCapacitor COUTDiode D and capacitor CRECAnd a load resistance RL；
The inductance LFOne end of the switch tube S is connected with5One end of the capacitor CFIs connected in parallel to the switch tube S5The inductance LFThe other end of the capacitor C is connected with a capacitor C2Of said switching tube S5The other end of the capacitor C is connected with a capacitor C2The other end of (a);
The capacitor CsAnd an inductance LsIn series with a simultaneous capacitor CsAnd an inductance LsConnected in parallel to a capacitor CFThe inductance LRECIs connected in parallel to the inductor LsThe inductance LRECone end of the capacitor C is connected with one end of the diode DRECConnected in parallel at two ends of a diode D, the other end of the diode D is connected with a capacitor COUTOne terminal of (C), a capacitorOUTanother end of the inductor L is connected with the inductor LRECThe other end of (1), the load resistance RLConnected in parallel to a capacitor COUTAt both ends of the same.
2. The DC/DC converter of claim 1, wherein the DC/DC converter comprises a switched capacitor and a resonant SEPIC circuit, and wherein: by opening a switching tube S1And S3Turn off the switch tube S2And S4By means of a capacitor C1High voltage reduction ratio and high power density are realized.
3. The DC/DC converter of claim 1, wherein the DC/DC converter comprises a switched capacitor and a resonant SEPIC circuit, and wherein: by opening a switching tube S2And S4Turn off the switch tube S1And S3By means of a capacitor C2high voltage reduction ratio and high power density are realized.
4. The DC/DC converter of claim 1, wherein the DC/DC converter comprises a switched capacitor and a resonant SEPIC circuit, and wherein: through soft charge mode, improve preceding stage switch capacitor circuit's efficiency.
5. The DC/DC converter of claim 1, wherein the DC/DC converter comprises a switched capacitor and a resonant SEPIC circuit, and wherein: through the inductance LcBear the voltage difference in the conversion process, reduce the transient current, thereby reducing the charge and discharge loss.
6. The DC/DC converter of claim 1, wherein the DC/DC converter comprises a switched capacitor and a resonant SEPIC circuit, and wherein: the method comprises the following steps of adopting stable output voltage during analog closed-loop control, adopting input during current source analog closed-loop control, determining amplitude, and determining the amplitude through the following formula:
Wherein, IINIs the amplitude, VOUTTo output a voltage, RLk is a constant related to the diode on duty ratio for the load resistance.
Technical Field
The invention relates to the technical field of voltage regulation, in particular to a DC/DC converter based on a switch capacitor and a resonant SEPIC circuit.
Background
with the rapid development of power electronic technology, nowadays, the demand for high-efficiency and high-power-density DC/DC power converters is more and more extensive, and in many digital products, integrated CPU circuits, large single-board hardware circuits and other occasions, a large number of low-voltage DC/DC power converters are used, which requires further miniaturization and high efficiency of the current DC/DC.
At present, the most effective measure for the miniaturization of the switching power supply is to improve the switching frequency of the switching power supply, when the frequency reaches the frequency of tens of MHz and above, the inductance value participating in resonance is very small, a non-magnetic core hollow inductor or a planar PCB inductor can be adopted, and the volume of a passive element is effectively reduced, so that the volume of the power converter is improved, and the power converter is mainly used for the design of the power converter with high power density. However, for high-frequency and ultrahigh-frequency power converters, there is a significant problem that the inverter generally adopts a class E inverter or an inverter with other similar structures derived therefrom, and due to the structural particularity, the voltage across the drain and source terminals of the switching tube is more than 3 times of the input voltage, so that the range of the input voltage is limited, and the inverter is not suitable for circuits with high step-down ratio.
In addition, the switched capacitor circuit is widely studied as a novel switching power supply structure, and the space occupied by the inductor or the transformer is greatly reduced in volume because no additional inductive element or less inductive elements are needed. The high voltage transformation ratio is well realized through capacitance voltage division and is commonly used in a DC/DC conversion circuit with high step-down ratio or high step-up ratio, but the power converter only consisting of a switched capacitor structure has low flexibility in output voltage regulation, and the application of the switched capacitor circuit in many occasions is limited.
Disclosure of Invention
The invention provides a DC/DC converter based on a switch capacitor and a resonant SEPIC circuit, which can ensure high efficiency and high power density while realizing high voltage reduction ratio, and provides the following technical scheme:
A DC/DC converter based on a switch capacitor and a resonance SEPIC circuit comprises a front stage switch capacitor circuit and a rear stage resonance SEPIC switch circuit;
The pre-stage switch capacitor circuit comprises four switch tubes S1、S2、S3And S4Two capacitors C1And C2inductor Lcand a voltage source Vin；
The voltage source VinThe positive terminal of the switch tube S1One end of (1), a switching tube S1The other end of the switch tube S2、S3And S4In series, said capacitor C1And a switching tube S2And S3Parallel connection, inductance LcAnd a capacitor C2One end of which is connected in series with an inductor LcAnd a capacitor C2Simultaneously with the switching tube S3And S4Parallel connection, a capacitor C2Is connected with a voltage source V at the other endinThe negative terminal of (1);
The post-stage resonance SEPIC switch circuit consists of an inverter circuit, a matching network and a rectifying circuit; the inverter circuit comprises an inductor LFCapacitor CFAnd a switching tube S5(ii) a The matching network comprises a capacitor CsAnd an inductance LsThe rectifier circuit comprises an inductor LRECCapacitor COUTDiode D and capacitor CRECAnd a load resistance RL；
The inductance LFOne end of the switch tube S is connected with5one end of the capacitor CFIs connected in parallel to the switch tube S5The inductance LFThe other end of the capacitor C is connected with a capacitor C2Of said switching tube S5The other end of the capacitor C is connected with a capacitor C2The other end of (a);
The capacitor CsAnd an inductance LsIn series with a simultaneous capacitor CsAnd an inductance LsConnected in parallel to a capacitor CFThe inductance LRECIs connected in parallel to the inductor LsThe inductance LRECOne end of the capacitor C is connected with one end of the diode DRECConnected in parallel at two ends of a diode D, the other end of the diode D is connected with a capacitor COUTOne terminal of (C), a capacitorOUTanother end of the inductor L is connected with the inductor LRECThe other end of (1), the load resistance RLConnected in parallel to a capacitor COUTAt both ends of the same.
preferably, by opening the switching tube S1And S3Turn off the switch tube S2And S4By means of a capacitor C1High voltage reduction ratio and high power density are realized.
Preferably, by opening the switching tube S2And S4Turn off the switch tube S1And S3By means of a capacitor C2High voltage reduction ratio and high power density are realized.
Preferably, the efficiency of the pre-stage switched capacitor circuit is improved by a soft charging mode.
Preferably, through the inductance LcBear the voltage difference in the conversion process, reduce the transient current, thereby reducing the charge and discharge loss.
preferably, the output voltage stable in the case of analog closed-loop control is adopted, the input in the case of analog closed-loop control is adopted as the current source, the amplitude is determined, and the amplitude is determined by the following formula:
Wherein, IINis the amplitude, VOUTTo output a voltage, RLK is a constant related to the diode on duty ratio for the load resistance.
The invention has the following beneficial effects:
1. The DC/DC power converter with high voltage reduction ratio is realized by two-stage voltage reduction of the switched capacitor circuit and the resonance Sepic circuit.
2. Through the working mode of soft charging, the efficiency of the switched capacitor circuit is greatly improved, the efficiency of the whole system is also improved, and the high efficiency of the system is realized.
3. The switched capacitor circuit and the resonance SEPIC circuit are both DC/DC power converters with higher high power density, and the high power density of the whole system is ensured by two stages.
Drawings
FIG. 1 is a schematic diagram of a DC/DC converter based on a switched capacitor and a resonant SEPIC circuit;
FIG. 2 is a soft charge characteristic switched capacitor circuit;
FIG. 3 is a diagram of switched capacitor operating modes;
FIG. 4 is an ultra high frequency resonant SEPIC power converter circuit;
FIG. 5 is a current mode resonant rectifier circuit;
FIG. 6 is a high-pass matching network topology;
FIG. 7 is a high frequency inverter circuit;
FIG. 8 shows a capacitor C1The simulation result graph of the discharge current waveform;
FIG. 9 includes LSTime-capacitor discharge current waveform diagram.
Detailed Description
The present invention will be described in detail with reference to specific examples.
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