High-gain SEPIC converter with extensible unit

Abstract

The utility model provides a high-gain SEPIC converter with extensible units. The high-gain SEPIC converter comprises a DC input source uin, a basic SEPIC converter and n extensible units. According to the utility model, the input and output voltage gains of the basic SEPIC converter can be effectively improved, 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. Besides, the expansion structure is simple and is only composed of two capacitors and two diodes, the structure does not contain magnetic elements, and the cost and the size of the converter can be effectively reduced.

Description

Technical Field

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

[0002] At present, photovoltaic power generation and energy storage batteries are widely used in the power industry. However, due to the low output voltage level of the DC power supply of the above new energy power generation methods and the high grid connection voltage, the voltage gain of traditional DC-DC converters is difficult to meet the high step-up requirements. Therefore, a high-gain DC-DC converter is needed 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 the application publication number CN116599343A discloses a high-gain Sepic converter and its control method. The converter uses parasitic capacitors Cs, inductors L3 and L4 to form a resonant network to achieve ZVS of the switching tube S; when S is turned off, the capacitor Cr2 is charged through the diode Dr; when S is turned off, the voltage applied to the inductors L3 and L4 is higher than that of the traditional Sepic circuit, achieving high gain and reducing the device voltage stress; at the same time, the switching tube can be controlled to work in different modes, realizing five working modes and expanding the application scenarios. However, this converter contains more inductor elements, which greatly increases the volume and cost of the converter, and the resonant network has high requirements for device design parameters and is difficult to design. In addition, its structure is not expandable and the voltage gain is relatively fixed, making it difficult to meet the high step-up requirements in different scenarios. Summary of the Utility Model

[0004] In order to solve the technical problems such as the low voltage gain of the basic SEPIC converter, insufficient step-up ability, and small adjustable range of the voltage gain. The utility model proposes a high-gain SEPIC converter with an expandable unit, which realizes high voltage gain and has multi-stage gain adjustment ability.

[0005] To achieve the above object, the technical solution adopted by the utility model is:

[0006] A high-gain SEPIC converter with an expandable unit, characterized in that: it includes a DC input source u in , a basic SEPIC converter, n an expansion unit, n where n is a natural number, and the value range is n≥1; among them:

[0007] The basic SEPIC converter includes a power switch S1, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, and a diode D1; their connection form is as follows: The left end of the first inductor L1 is connected to the positive pole of the DC input source, the right end of the first inductor L1 is connected to the drain of the power switch S1 and the left end of the second capacitor C2, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the right end of the second capacitor C2 is connected to the anode of the diode D1 and the upper end of the second inductor L2, the cathode of the diode D1 is connected to the upper end of the first capacitor C1, the lower end of the first capacitor C1 is connected to the lower end of the second inductor L2, the source of the power switch S1, and the negative pole of the DC input source;

[0008] The expansion unit includes two diodes and two capacitors;

[0009] When n = 1, the first expansion unit includes a first capacitor C 11 , a second capacitor C 12 , a first diode D 11 , a second diode D 12 ; among them, the left end of the second capacitor C 12 of the first expansion unit is connected to the anode of the diode D1 of the basic SEPIC converter, the right end of the second capacitor C 12 is connected to the anode of the first diode D 11 and the cathode of the second diode D 12 , the anode of the second diode D 12 is connected to the cathode of the diode D1 of the basic SEPIC converter, the upper end of the first capacitor C 11 is connected to the cathode of the first diode D 11 , the lower end of the first capacitor C 11 is connected to the anode of the second diode D 12 , forming the first expansion unit;

[0010] When n = 2, the anode of the second diode D 22 of the second expansion unit is connected to the cathode of the first diode D 11 of the first expansion unit, the upper end of the first capacitor C 21 of the second expansion unit is connected to the cathode of the first diode D 11 of the first expansion unit. When n > 2, each expansion unit is connected in sequence from bottom to top in this way until the anode of the second diode D 22 of the nth expansion unit is connected to the cathode of the first diode D 11 of the (n - 1)th expansion unit, and the upper end of the first capacitor C 21 of the nth expansion unit is connected to the cathode of the first diode D 11 of the (n - 1)th expansion unit;

[0011] LoadR Both ends of n are respectively connected to the first capacitor C n1 in the -th expansion unit at the upper end and the lower end of the first capacitor C1 in the basic SEPIC converter.

[0012] When two expansion units are adopted, when the power switch S1 is turned on, the second diode D 12 of the first expansion unit and the second diode D 22 of the second expansion unit are turned on, the diode D1 of the basic SEPIC converter, the first diode D 11 of the first expansion unit, and the first diode D 21 of the second expansion unit are turned off, and the input voltage u in charges the first inductor L1 and the second inductor L2. The currents of the first inductor L1 and the second inductor L2 rise, and the first capacitor C1 and the second capacitor C2 of the basic SEPIC converter, the first capacitor C 11 and the second capacitor C 12 of the first expansion unit, the first capacitor C 21 and the second capacitor C 22 of the second expansion unit discharge to supply power to the load.

[0013] When two expansion units are adopted, when the power switch S1 is turned off, the second diode D 12 of the first expansion unit and the second diode D 22 of the second expansion unit are turned off, the diode D1 of the basic SEPIC converter, the first diode D 11 of the first expansion unit, and the first diode D 21 of the second expansion unit are turned on. The first inductor L1 and the second inductor L2 discharge, and the inductor current drops. The input voltage u in and the first inductor L1 and the second inductor L2 pass through the first diode D1 of the basic SEPIC converter and the first diode D 11 of the first expansion unit and the first diode D 21 of the second expansion unit to charge the first capacitor C1 of the basic SEPIC converter and the first capacitor C 11 and the second capacitor C 12 of the first expansion unit, the first capacitor C 21 and the second capacitor C 22 of the second expansion unit, and at the same time supply power to the load.

[0014] Its input-output gain is adjusted by regulating the number of expansion units, achieving the ability of high-gain multi-stage voltage regulation. The voltage gain that each expansion unit can improve is 1 / (1-D), and the overall voltage gain of the converter is ( n + D ) / (1-D).

[0015] A high-gain SEPIC converter with expandable units according to the present utility model has the following technical effects:

[0016] 1) It can effectively improve the input-output voltage gain of the basic SEPIC converter, avoiding the situation of extreme duty cycles for achieving a large voltage gain.

[0017] 2) The expansion unit in the present utility model has a simple structure and a small number of devices, avoiding complex structures and high costs while increasing the voltage gain of the converter.

[0018] 3) The present utility model can adopt different numbers of expansion units according to specific application scenarios, thereby achieving different voltage gain requirements, effectively expanding the applicability of the converter, and being more suitable for high-boost scenarios. Description of the Drawings

[0019] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0020] Figure 1 is the specific circuit schematic diagram of the present utility model with 2 expansion units.

[0021] Figure 2 is the present utility model with n expansion units of the specific circuit schematic diagram.

[0022] Figure 3 is the voltage gain comparison curve of the present utility model with 2 expansion units, 4 expansion units, and 6 expansion units. Detailed Embodiment

[0023] Figure 1 A high-gain DC / DC converter with expandable units shown contains a DC input source u in , a basic SEPIC converter, and 2 expansion units; where:

[0024] The basic SEPIC converter includes a power switch S1, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, and a diode D1; their connection form is as follows: the left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1 and the left end of the capacitor C2, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the right end of the capacitor C2 is connected to the anode of the diode D1 and the upper end of the inductor L2, the cathode of the diode D1 is connected to the upper end of the capacitor C1, the lower end of the capacitor C1 is connected to the lower end of the inductor L2, the source of the power switch S1, and the negative pole of the DC input source; the expansion unit includes two diodes and two capacitors.

[0025] The first expansion unit includes a capacitor C 11 , a capacitor C 12 , a diode D 11 , and a diode D 12 ; among them, the left end of the capacitor C 12 in the first expansion unit is connected to the anode of the diode D1 in the basic SEPIC converter, the right end of the capacitor C 12 is connected to the anode of the diode D 11 and the cathode of the diode D 12 , the anode of the diode D 12 is connected to the cathode of the diode D1 in the basic SEPIC converter, the upper end of the capacitor C 11 is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 11 is connected to the anode of the diode D 12 , forming the first expansion unit.

[0026] The second expansion unit includes a capacitor C 21 , a capacitor C 22 , a diode D 21 , and a diode D 22 ; among them, the left end of the capacitor C 22 in the second expansion unit is connected to the left end of the capacitor C 12 in the first expansion unit, the right end of the capacitor C 22 is connected to the anode of the diode D 21 and the cathode of the diode D 22 , the anode of the diode D 22 in the second expansion unit is connected to the cathode of the diode D 11 in the first expansion unit, the upper end of the capacitor C 21 in the second expansion unit is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 21 is connected to the anode of the diode D 22 , forming the second expansion unit.

[0027] LoadR Both ends of which are respectively connected to the capacitors in the second extended unit C 21 The upper end of and the lower end of the capacitor C1 in the basic SEPIC converter

[0028] When two extended units are adopted, when the power switch S1 is turned on, the diode D 12 、D 22 Conduct, the diodes D1 and the diode D 11 、D 21 Turn off, the input voltage u in Charges the inductors L1 and L2, the currents of the inductors L1 and L2 rise, and the capacitors C1, C2 and the capacitors C 11 、C 12 In the first extended unit and the capacitors C 21 、C 22 In the second extended unit discharge to supply power to the load

[0029] When two extended units are adopted, when the power switch S1 is turned off, the diode D 12 、D 22 Turn off, the diodes D1 and the diode D 11 、D 21 Conduct, the inductors L1 and L2 discharge, the inductor current drops, and the input voltage u in And the inductors L1 and L2 pass through the diode D1 and the diode D in the first extended unit 11 And the diode D in the second extended unit 21 Charge the capacitor C1 and the capacitors C 11 、C 12 In the first extended unit and the capacitors C 21 、C 22 In the second extended unit, and supply power to the load at the same time

[0030] Figure 2 A high-gain DC / DC converter with an expandable unit shown includes a DC input source u in ,a basic SEPIC converter, n Extended units; where:

[0031] The basic SEPIC converter includes a power switch S1, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, and a diode D1; their connection form is as follows: the left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1 and the left end of the capacitor C2, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the right end of the capacitor C2 is connected to the anode of the diode D1 and the upper end of the inductor L2, the cathode of the diode D1 is connected to the upper end of the capacitor C1, and the lower end of the capacitor C1 is connected to the lower end of the inductor L2, the source of the power switch S1, and the negative pole of the DC input source; the expansion unit includes two diodes and two capacitors.

[0032] The first expansion unit includes a capacitor C 11 , a capacitor C 12 , a diode D 11 , and a diode D 12 ; among them, the left end of the capacitor C 12 in the first expansion unit is connected to the anode of the diode D1 in the basic SEPIC converter, the right end of the capacitor C 12 is connected to the anode of the diode D 11 and the cathode of the diode D 12 , the anode of the diode D 12 is connected to the cathode of the diode D1 in the basic SEPIC converter, the upper end of the capacitor C 11 is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 11 is connected to the anode of the diode D 12 , forming the first expansion unit.

[0033] The second expansion unit includes a capacitor C 21 , a capacitor C 22 , a diode D 21 , and a diode D 22 ; among them, the left end of the capacitor C 22 in the second expansion unit is connected to the left end of the capacitor C 12 in the first expansion unit, the right end of the capacitor C 22 is connected to the anode of the diode D 21 and the cathode of the diode D 22 , the anode of the diode D 22 in the second expansion unit is connected to the cathode of the diode D 11 in the first expansion unit, the upper end of the capacitor C 21 in the second expansion unit is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 21 is connected to the anode of the diode D 22 , forming the second expansion unit.

[0034] nThe extension units are connected in sequence from bottom to top. That is, the left end of the capacitor C of the second extension unit 22 is connected to the left end of the capacitor C of the first extension unit 12 The anode of the diode D of the second extension unit 22 is connected to the cathode of the diode D of the first extension unit 11 And so on until the n th extension unit;

[0035] n n is a natural number, and its value range is n n≥1, and the structures of all extension units are the same;

[0036] Load R The two ends of the load are respectively connected to the upper end of the capacitor n in the nth extension unit and the lower end of the capacitor C1 in the basic SEPIC converter. C n1

[0037] When two extension units are used, when the power switch S1 is turned on, the diodes D 12 and D 22 conduct, and the diodes D1 and D 11 and D 21 turn off. The input voltage u in charges the inductors L1 and L2. The currents of the inductors L1 and L2 increase, and the capacitors C1, C2, and the capacitors C 11 and C 12 of the first extension unit and the capacitors C 21 and C 22 and C 12 of the second extension unit discharge to supply power to the load.

[0038] When two extension units are used, when the power switch S1 is turned off, the diodes D 12 and D 22 turn off, and the diodes D1 and D 11 and D 21 conduct. The inductors L1 and L2 discharge, and the inductor current decreases. The input voltage u in and the inductors L1 and L2 charge the capacitor C1 and the capacitors C 11 and C 21 of the first extension unit and the capacitors C 11 and C 12 and C 21 and C 22 of the second extension unit through the diode D1 and the diodes D of the first extension unit

[0039] Its input-output gain is adjusted by regulating the number of expansion units, achieving the ability of high-gain multi-stage voltage regulation. The voltage gain that each expansion unit can increase is 1 / (1 - D), and the overall voltage gain of the converter is ( n +) D ) / (1 - D).

[0040] It can be seen that under the condition of the same duty cycle, the voltage gain of the converter can be effectively increased by adding expansion units, solving the problems of low voltage gain and insufficient boosting ability of the traditional SEPIC converter. Figure 3

[0041] The above are only specific embodiments of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the protection scope of the present invention.

[0042] It should be noted that the terms "including" and "having" and any variations thereof in the description, claims and drawings of the present invention are intended to cover non-exclusive inclusion. The terms "installed", "set up", "equipped with", "connected", "linked", "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 the internal connection between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "one end", "the other end", "outer side", "inner side", "horizontal", "end", "length", "outer end", "left", "right", "up", "down", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 should not be construed as a limitation of the present invention. The terms "first" and "second" are also used only for the sake of simplicity in description and do not indicate or imply relative importance.​

Claims

1. A high-gain SEPIC converter with expandable units, characterized in that: comprises a DC input source u in , a basic SEPIC converter, and n extended units, where n is a natural number and the value range is n≥1; wherein: The basic SEPIC converter includes a power switch S1, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, and a diode D1; their connection form is as follows: the left end of the first inductor L1 is connected to the positive pole of the DC input source, the right end of the first inductor L1 is connected to the drain of the power switch S1 and the left end of the second capacitor C2, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the right end of the second capacitor C2 is connected to the anode of the diode D1 and the upper end of the second inductor L2, the cathode of the diode D1 is connected to the upper end of the first capacitor C1, and the lower end of the first capacitor C1 is connected to the lower end of the second inductor L2, the source of the power switch S1, and the negative pole of the DC input source; The expansion unit includes two diodes and two capacitors; When n = 1, the first extended unit includes a first capacitor C 11 , a second capacitor C 12 , a first diode D 11 , a second diode D 12 ; wherein, the left end of the second capacitor C 12 of the first extended unit is connected to the anode of the diode D1 of the basic SEPIC converter, and the right end of the second capacitor C 12 is connected to the anode of the first diode D 11 and the cathode of the second diode D 12 , the anode of the second diode D 12 is connected to the cathode of the diode D1 of the basic SEPIC converter, the upper end of the first capacitor C 11 is connected to the cathode of the first diode D 11 , and the lower end of the first capacitor C 11 is connected to the anode of the second diode D 12 , forming the first extended unit; When n = 2, the anode of the second diode D of the second expansion unit 22 is connected to the cathode of the first diode D of the first expansion unit 11 The upper end of the first capacitor C of the second expansion unit 21 is connected to the cathode of the first diode D of the first expansion unit 11 When n > 2, each expansion unit is connected in sequence from bottom to top in this way until the anode of the second diode D of the nth expansion unit 22 is connected to the cathode of the first diode D of the (n - 1)th expansion unit 11 The upper end of the first capacitor C of the nth expansion unit 21 is connected to the cathode of the first diode D of the (n - 1)th expansion unit 11 is connected; Both ends of the load R are respectively connected to the upper end of the first capacitor C in the nth extended unit and the lower end of the first capacitor C1 in the basic SEPIC converter. n1 and the lower end of the first capacitor C1 in the basic SEPIC converter.

2. The high-gain SEPIC converter with an expandable unit according to claim 1, wherein: When two expansion units are adopted, when the power switch S1 is turned on, the second diode D of the first expansion unit 12 , the second diode D of the second expansion unit 22 conducts, the diode D1 of the basic SEPIC converter, the first diode D of the first expansion unit 11 , the first diode D of the second expansion unit 21 turns off, the input voltage u in charges the first inductor L1 and the second inductor L2, the currents of the first inductor L1 and the second inductor L2 rise, the first capacitor C1 and the second capacitor C2 of the basic SEPIC converter, the first capacitor C of the first expansion unit 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.

3. The high-gain SEPIC converter with an expandable unit according to claim 1, wherein: When two expansion units are adopted, when the power switch S1 is turned off, the second diode D of the first expansion unit 12 , the second diode D of the second expansion unit 22 turns off. The diode D1 of the basic SEPIC converter, the first diode D of the first expansion unit 11 , the first diode D of the second expansion unit 21 turn on. The first inductor L1 and the second inductor L2 discharge, the inductor current drops, and the input voltage u in and the first inductor L1 and the second inductor L2 supply power to the first capacitor C1 of the basic SEPIC converter, the first capacitor C of the first expansion unit 11 and the second capacitor C of the second expansion unit 21 through the first diode D1 of the basic SEPIC converter and the first diode D of the first expansion unit 11 and the first diode D of the second expansion unit 12 and charge the first C of the second expansion unit capacitor 21 and the second capacitor C 22 while supplying power to the load.

Images