High-gain DC-DC converter with extensible structure

Abstract

The utility model provides a high-gain DC-DC converter with an extensible structure. The high-gain DC-DC converter comprises a DC input source uin, a basic Buck-Boost converter, an auxiliary diode DP, an auxiliary capacitor CP and n expansion units. According to the Buck-Boost converter, the input and output voltage gain of the basic Buck-Boost converter can be effectively improved, and the occurrence of an extreme duty ratio is avoided. The expansion unit does not contain a magnetic element and is only composed of two capacitors and two diodes, so that the excessive increase of the cost and the size of the converter is effectively avoided. And the number of the expansion units is adjustable, and different numbers of expansion units can be adopted according to specific application occasions, so that different voltage gain requirements are realized, and the applicability of the converter in a high boost occasion is effectively expanded.

Description

Technical Field

[0001] The utility model relates to a DC-DC converter, in particular to a high-gain DC-DC converter with an expandable structure. Background Art

[0002] At present, new energy sources such as photovoltaic power generation and energy storage batteries are widely used. However, since the DC power supply output voltage level of the above-mentioned new energy power generation methods is low and the grid-connected voltage is high, the voltage gain of the traditional DC / DC converter is difficult to meet the high voltage boost demand. Therefore, a high-gain DC / DC converter is required to convert the low voltage of the new energy power supply into the high voltage required for grid connection.

[0003] In order to improve the voltage gain, for example, the patent document with application publication number CN115347796A discloses a high-power density ZVS high-gain converter based on common-mode inductors, which includes two switching tubes, two diodes, a three-winding transformer, a common-mode inductor and five capacitors; the voltage stress of all power tubes is low, and low-voltage devices can be used, reducing system cost and conduction loss; ZVS turn-on of all switching tubes and ZCS turn-off of all diodes are achieved, reducing switching losses; common-mode inductors are used, and mutual inductance is used to increase their equivalent inductance, thereby reducing the number of turns required for the inductor, and reducing one magnetic core, so that the volume and weight of the converter are reduced; by reasonably designing the excitation inductance and turns ratio of the three-winding transformer, the switching frequency ripple of the input current can be completely eliminated, so there is no need for input filter capacitors, which improves reliability; and a voltage gain of more than 10 times can be achieved without working at an extreme duty cycle. However, the converter contains many active switches and magnetic components, with complex control methods, high size and cost. In addition, its structure is not scalable, and its voltage gain is relatively fixed, making it difficult to adapt to high voltage boost requirements in different scenarios. Utility Model Content

[0004] In order to solve the technical problems of low voltage gain, insufficient voltage boosting capability and small adjustable range of voltage gain of basic DC-DC converter, the utility model proposes a high-gain DC-DC converter with expandable structure, which realizes high voltage gain and has multi-level gain adjustment capability.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A high-gain DC-DC converter with an expandable structure, characterized in that it includes a DC input source uin, a basic Buck-Boost converter, an auxiliary diode D P , an auxiliary capacitor C P , n expansion units, n is a natural number, the value range is n≥1; where:

[0007] The basic Buck-Boost converter consists of a power switch S 1 、Inductance L 1 , capacitor C 1 、Diode D 1 ; Its connection form is as follows: power switch S 1 The drain of the power switch S is connected to the positive terminal of the DC input source. 1 The source is connected to the inductor L 1 The upper end and capacitor C 1 The left end of the inductor L 1 The lower end is connected to the negative electrode of the DC input source and the diode D 1 The anode of the capacitor C 1 The right end of the diode D 1 The cathode;

[0008] The extension unit contains two diodes and two capacitors;

[0009] When n=1, the first expansion unit contains the first capacitor C 11 , the second capacitor C 12 , the first diode D 11 , the second diode D 12 ; Among them, the second capacitor C of the first expansion unit 12 The left end of the basic Buck-Boost converter capacitor C 1 The left end is connected to the second capacitor C 12 The right end of the first diode D 11 The anode of the second diode D 12 The cathode of the second diode D is connected 12 The anode of the diode D 1 The cathode of the first capacitor C 11 The upper end of the first diode D 11 The cathode of the first capacitor C 11 The lower end of the second diode D 12 The anode of the first expansion unit is connected to form the first expansion unit; the first expansion unit is connected to the anode of the first expansion unit through the auxiliary diode D P Connected to the basic Buck-Boost converter, i.e. the auxiliary diode D P The anode of the basic Buck-Boost converter diode D 1 The cathode of the auxiliary diode D P The cathode of the second diode D of the first expansion unit 12 Anode connection; auxiliary capacitor C P The lower end of the basic Buck-Boost converter diode D 1 The anode connection of the auxiliary capacitor C P The upper end of the auxiliary diode DP The cathode connection of

[0010] When n=2, the left end of the second capacitor C22 of the second expansion unit is connected to the second capacitor C 12 The left end of the second expansion unit, the second diode D 22 The anode of the first expansion unit is connected to the first diode D 11 When n>2, the expansion units are connected sequentially from bottom to top in this way, until the left end of the second capacitor of the nth expansion unit is connected to the left end of the second capacitor of the n-1th expansion unit, and the anode of the second diode of the nth expansion unit is connected to the cathode of the first diode of the n-1th expansion unit;

[0011] The two ends of the load R are connected to the first capacitor C in the nth expansion unit. n1 The upper end and the capacitor C in the basic Buck-Boost converter 1 The lower end is connected.

[0012] When two expansion units are used, the power switch S 1 When conducting, diode D 1 , D 12 , D 22 Turn off, diode D P , D 11 , D 21 On, input voltage u in Add inductor L 1 On, the inductor L 1 The current rises, the input voltage u in is the inductance L 1 and capacitor C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Charging and supplying power to the load at the same time.

[0013] When two expansion units are used, the power switch S 1 When off, the diode D 1 , D 12 , D 22 Conducting, diode D P , D 11 , D 21 Turn off, inductor L 1 The current drops, the inductor L 1 、Diode D 1 and the diode D of the first expansion unit 11 and the diode D of the second expansion unit21 is the capacitance C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Discharge to supply power to the load.

[0014] In the utility model, the input and output gains are adjusted by adjusting the number of expansion units to achieve high-gain multi-stage voltage regulation capability. Each expansion unit can increase the voltage gain by 1 / (1-D), and the overall voltage gain of the converter is (n+1) / (1-D).

[0015] The utility model has an expandable high-gain DC-DC converter, and the technical effects are as follows:

[0016] 1) It can effectively improve the input and output voltage gain of the basic Buck-Boost converter, reduce the device voltage stress, and avoid the situation of using extreme duty cycle to achieve a larger voltage gain.

[0017] 2) The expansion unit does not contain magnetic components, thus avoiding a large increase in volume and cost while improving the voltage gain of the converter.

[0018] 3) The utility model can adopt different numbers of expansion units according to specific application scenarios, so as to achieve different voltage gain requirements, effectively expanding the applicability of the converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0020] Figure 1 It is a specific circuit principle diagram of the utility model containing two expansion units.

[0021] Figure 2 This is a specific circuit schematic diagram containing n expansion units mentioned in the utility model.

[0022] Figure 3 The utility model is a voltage gain comparison curve when it contains 2 expansion units, 4 expansion units and 6 expansion units and a voltage gain comparison curve of a basic SEPIC converter. DETAILED DESCRIPTION

[0023] Figure 1 The structure of a scalable high-gain DC-DC converter shown in FIG. 1 includes a DC input source u in , a basic Buck-Boost converter, an auxiliary diode D P , an auxiliary capacitor C P, n expansion units; among which:

[0024] The basic Buck-Boost converter consists of a power switch S 1 、Inductance L 1 , capacitor C 1 、Diode D 1 ; Its connection form is as follows: power switch S 1 The drain of the power switch S is connected to the positive terminal of the DC input source. 1 The source is connected to the inductor L 1 The upper end and capacitor C 1 The left end of the inductor L 1 The lower end is connected to the negative electrode of the DC input source and the diode D 1 The anode of the capacitor C 1 The right end of the diode D 1 The cathode;

[0025] The expansion unit contains two diodes and two capacitors; the first expansion unit is connected through an auxiliary diode D P Connected to the basic Buck-Boost converter, i.e. the auxiliary diode D P The anode of the basic Buck-Boost converter diode D 1 The cathode of the auxiliary diode D P The cathode of the first expansion unit diode D 12 Anode connection; auxiliary capacitor C P The lower end of the basic Buck-Boost converter diode D 1 The anode connection of the auxiliary capacitor C P The upper end of the auxiliary diode D P The cathode connection of

[0026] The first expansion unit contains capacitor C 11 , capacitor C 12 、Diode D 11 、Diode D 12 ; Among them, the first expansion unit capacitor C 12 The left end of the basic Buck-Boost converter capacitor C 1 The left end of the capacitor C 12 The right end of the diode D 11 The anode and diode D 12 The cathode of the diode D is connected 12 The anode of the diode D 1 The cathode connection of capacitor C 11 The upper end of the diode D 11 The cathode connection of capacitor C 11 The lower end of the diode D 12The anode of is connected to form the first expansion unit;

[0027] The second expansion unit contains capacitor C 21 , capacitor C 22 、Diode D 21 、Diode D 22 ; Among them, the second expansion unit capacitor C 22 The left end is connected to the first expansion unit C 12 The left end of the capacitor C 22 The right end of the diode D 21 The anode and diode D 22 The cathode connection of the second expansion unit diode D 22 The anode of the first expansion unit diode D 11 The cathode of the second expansion unit capacitor C 21 The upper end of the diode D 11 The cathode connection of capacitor C 21 The lower end of the diode D 22 The anode of is connected to form the second expansion unit;

[0028] The two ends of the load R are connected to the capacitor C in the second expansion unit. 21 The upper end and the capacitor C in the basic Buck-Boost converter 1 The lower end is connected.

[0029] When two expansion units are used, the power switch S 1 When conducting, diode D 1 , D 12 , D 22 Turn off, diode D P , D 11 , D 21 On, input voltage u in Add inductor L 1 On, the inductor L 1 The current rises, the input voltage u in is the inductance L 1 and capacitor C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Charging and supplying power to the load at the same time.

[0030] When two expansion units are used, the power switch S 1 When off, the diode D 1 , D 12 , D 22 Conducting, diode DP , D 11 , D 21 Turn off, inductor L 1 The current drops, the inductor L 1 、Diode D 1 and the diode D of the first expansion unit 11 and the diode D of the second expansion unit 21 is the capacitance C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Discharge to supply power to the load.

[0031] Figure 2 The structure of a scalable high-gain DC-DC converter shown in FIG. 1 includes a DC input source u in , a basic Buck-Boost converter, an auxiliary diode D P , an auxiliary capacitor C P , n expansion units; among which:

[0032] The basic Buck-Boost converter consists of a power switch S 1 、Inductance L 1 , capacitor C 1 、Diode D 1 ; Its connection form is as follows: power switch S 1 The drain of the power switch S is connected to the positive terminal of the DC input source. 1 The source is connected to the inductor L 1 The upper end and capacitor C 1 The left end of the inductor L 1 The lower end is connected to the negative electrode of the DC input source and the diode D 1 The anode of the capacitor C 1 The right end of the diode D 1 The cathode;

[0033] The expansion unit contains two diodes and two capacitors; the first expansion unit is connected through an auxiliary diode D P Connected to the basic Buck-Boost converter, i.e. the auxiliary diode D P The anode of the basic Buck-Boost converter diode D 1 The cathode of the auxiliary diode D P The cathode of the first expansion unit diode D 12 Anode connection; auxiliary capacitor C P The lower end of the basic Buck-Boost converter diode D 1The anode connection of the auxiliary capacitor C P The upper end of the auxiliary diode D P The cathode connection of

[0034] The first expansion unit contains capacitor C 11 , capacitor C 12 、Diode D 11 、Diode D 12 ; Among them, the first expansion unit capacitor C 12 The left end of the basic Buck-Boost converter capacitor C 1 The left end of the capacitor C 12 The right end of the diode D 11 The anode and diode D 12 The cathode of the diode D is connected 12 The anode of the diode D 1 The cathode connection of capacitor C 11 The upper end of the diode D 11 The cathode connection of capacitor C 11 The lower end of the diode D 12 The anode of is connected to form the first expansion unit;

[0035] The second expansion unit contains capacitor C 21 , capacitor C 22 、Diode D 21 、Diode D 22 ; Among them, the second expansion unit capacitor C 22 The left end is connected to the first expansion unit C 12 The left end of the capacitor C 22 The right end of the diode D 21 The anode and diode D 22 The cathode connection of the second expansion unit diode D 22 The anode of the first expansion unit diode D 11 The cathode of the second expansion unit capacitor C 21 The upper end of the diode D 11 The cathode connection of capacitor C 21 The lower end of the diode D 22 The anode of is connected to form the second expansion unit;

[0036] The n expansion units are connected in order from bottom to top, that is, the capacitor C of the second expansion unit 22 The left end is connected to the first expansion unit C 12 The left end of the second expansion unit diode D 22 The anode of the first expansion unit diode D 11 The cathode of the device; and so on, until the nth expansion unit;

[0037] n is a natural number, and its value range is n≥1; each expansion unit has the same structure.

[0038] The two ends of the load R are connected to the capacitor C in the nth expansion unit. n1 The upper end and the capacitor C in the basic Buck-Boost converter 1 The lower end is connected.

[0039] When two expansion units are used, the power switch S 1 When conducting, diode D 1 , D 12 , D 22 Turn off, diode D P , D 11 , D 21 On, input voltage u in Add inductor L 1 On, the inductor L 1 The current rises, the input voltage u in is the inductance L 1 and capacitor C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Charging and supplying power to the load at the same time.

[0040] When two expansion units are used, the power switch S 1 When off, the diode D 1 , D 12 , D 22 Conducting, diode D P , D 11 , D 21 Turn off, inductor L 1 The current drops, the inductor L 1 、Diode D 1 and the diode D of the first expansion unit 11 and the diode D of the second expansion unit 21 is the capacitance C 1 、Auxiliary capacitor C P and the first expansion unit capacitor C 11 , C 12 and the second expansion unit capacitor C 21 , C 22 Discharge to supply power to the load.

[0041] The input and output gain is adjusted by adjusting the number of expansion units to achieve high-gain multi-stage voltage regulation capability. Each expansion unit can increase the voltage gain by 1 / (1-D), and the overall voltage gain of the converter is (n+1) / (1-D).

[0042] Depend on Figure 3 It can be seen that under the same duty cycle, the voltage gain of the converter can be effectively improved by adding an extension unit, solving the problem of low voltage gain and insufficient boost capability of the basic Buck-Boost converter.

[0043] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the protection scope of the present invention.

[0044] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the utility model and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances.

[0045] In the description of the present invention, it should be understood that the terms "one end", "the other end", "outside", "inside", "horizontal", "end", "length", "outer end", "left", "right", "upper", "lower" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The terms "first" and "second" are also used only for simplicity of description, and do not indicate or imply relative importance.

Claims

1. A high-gain DC-DC converter with an expandable structure, characterized in that: It includes a DC input source uin, a basic Buck-Boost converter, an auxiliary diode D P , an auxiliary capacitor C P , n expansion units, n is a natural number, the value range is n≥1; where: The basic Buck-Boost converter includes a power switch S1, an inductor L1, a capacitor C1, and a diode D1; the connection form is as follows: the drain of the power switch S1 is connected to the positive electrode of the DC input source, the source of the power switch S1 is connected to the upper end of the inductor L1 and the left end of the capacitor C1, the lower end of the inductor L1 is connected to the negative electrode of the DC input source and the anode of the diode D1, and the right end of the capacitor C1 is connected to the cathode of the diode D1; The extension unit contains two diodes and two capacitors; When n=1, the first expansion unit contains the first capacitor C 11 , the second capacitor C 12 , the first diode D 11 , the second diode D 12 ; Among them, the second capacitor C of the first expansion unit 12 The left end of the capacitor C1 is connected to the left end of the basic Buck-Boost converter. 12 The right end of the first diode D 11 The anode of the second diode D 12 The cathode of the second diode D is connected 12 The anode of the diode D1 is connected to the cathode of the first capacitor C 11 The upper end of the first diode D 11 The cathode of the first capacitor C 11 The lower end of the second diode D 12 The anode of the first expansion unit is connected to form the first expansion unit; the first expansion unit is connected to the anode of the first expansion unit through the auxiliary diode D P Connected to the basic Buck-Boost converter, i.e. the auxiliary diode D P The anode of the basic Buck-Boost converter diode D1 is connected to the cathode of the auxiliary diode D P The cathode of the second diode D of the first expansion unit 12 Anode connection; auxiliary capacitor C P The lower end of the basic Buck-Boost converter diode D1 is connected to the anode, and the auxiliary capacitor C P The upper end of the auxiliary diode D P The cathode connection of When n=2, the left end of the second capacitor C22 of the second expansion unit is connected to the second capacitor C 12 The left end of the second expansion unit, the second diode D 22 The anode of the first expansion unit is connected to the first diode D 11 When n>2, the expansion units are connected sequentially from bottom to top in this way, until the left end of the second capacitor of the nth expansion unit is connected to the left end of the second capacitor of the n-1th expansion unit, and the anode of the second diode of the nth expansion unit is connected to the cathode of the first diode of the n-1th expansion unit; The two ends of the load R are connected to the first capacitor C in the nth expansion unit. n1 The upper end of is connected to the lower end of capacitor C1 in the basic Buck-Boost converter.

2. A high-gain DC-DC converter with an expandable structure according to claim 1, characterized in that: When two expansion units are used, when the power switch S1 is turned on, the diode D1 of the basic Buck-Boost converter and the second diode D 12 , the second diode D of the second expansion unit 22 Turn off, auxiliary diode D P , the first diode D of the first expansion unit 11 , the first diode D of the second expansion unit 21 On, input voltage u in Added to the inductor L1, the current of the inductor L1 increases, and the input voltage u in is the inductor L1 and the capacitor C1 and auxiliary capacitor C of the basic Buck-Boost converter. P and the first expansion unit first capacitor C 11 and the second capacitor C 12 , the first capacitor C of the second expansion unit 21 and the second capacitor C 22 Charging and supplying power to the load at the same time.

3. The high-gain DC-DC converter with an expandable structure according to claim 1, characterized in that: When two expansion units are used, when the power switch S1 is turned off, the diode D1 of the basic Buck-Boost converter and the second diode D 12 , the second diode D of the second expansion unit 22 Conducting, auxiliary diode D P , the first diode D of the first expansion unit 11 , the first diode D of the second expansion unit 21 The current of the inductor L1 decreases, and the inductor L1, the diode D1 of the basic Buck-Boost converter and the first diode D 11 and the second diode D of the second expansion unit 21 The basic Buck-Boost converter capacitor C1 and auxiliary capacitor C P and the first expansion unit first capacitor C 11 and the second capacitor C 12 , the first capacitor C of the second expansion unit 21 and the second capacitor C 22 Discharge to supply power to the load.

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