A non-isolated dc-dc converter based on switched capacitor inductor and control method

Abstract

The application discloses a non-isolated DC-DC converter based on a switched capacitor inductor and a control method. in The application discloses a non-isolated DC-DC converter based on a switched capacitor inductor, which comprises a direct-current voltage source V in , a first switch tube S1, a second switch tube S2, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and an output load R0. The application connects capacitors in series between the direct-current voltage source and the output load, so that the non-isolated DC-DC converter has a voltage isolation effect and reliability is improved. Compared with other converters, the application has only two linear working modes, and operation is simple. Meanwhile, conduction loss is low, and the converter has high efficiency.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a non-isolated DC-DC converter and control method based on switched capacitors and inductors. Background Technology

[0002] With the rapid pace of industrialization, informatization, urbanization, and modernization, human demand for energy is increasing. The shortage of fossil fuels and environmental problems have become pressing issues that must be addressed. Developing and utilizing renewable energy is a crucial way to solve these problems. However, the output voltage of renewable energy sources is often insufficient, necessitating the use of high-voltage boost DC-DC converters to increase the output voltage. High-voltage boost DC-DC converters are divided into isolated and non-isolated types. Non-isolated converters are widely used due to their high conversion efficiency, low losses, and simple design.

[0003] In existing technologies, high voltage gain and minimal input current ripple can be provided by combining two boost converters with winding cross-coupled inductors and voltage multipliers. However, this approach has drawbacks such as high cost, large size, and complex design. Another approach is to increase voltage gain by controlling the number of turns of the coupled inductor, but this results in leakage inductance and reduced efficiency. Yet another approach is to achieve high voltage gain through cascaded converters, but this makes the control unit more complex due to the use of a large number of components.

[0004] Patent publication number CN110048611A, entitled "High Voltage Gain Soft-Switching DC-DC Converter Based on Switched Capacitors and Coupled Inductors," addresses the problem that existing soft-switching DC-DC converters, in order to achieve a high boost ratio, generate large turn-off voltage spikes in the switching transistors, thus affecting converter efficiency. Based on switched capacitors and coupled inductors, a high voltage gain DC-DC converter topology is proposed. This patent application utilizes parallel charging and series discharging of switched capacitors, combined with coupled inductors, to achieve a high boost ratio and reduce voltage stress on the switching transistors and diodes. However, this patent application cannot solve the problems of low gain, high switching losses, a large number of components, and complex design. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the purpose of this invention is to provide a non-isolated DC-DC converter and control method based on switched capacitors and inductors, thereby realizing a high-gain, low-loss DC-DC converter.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A non-isolated DC-DC converter based on switched capacitors and inductors includes: a DC voltage source V inThe components are: first switch S1, second switch S2, first diode D1, second diode D2, third diode D3, fourth diode D4, first inductor L1, second inductor L2, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, and output load R0.

[0008] The first terminal of the first inductor L1 is connected to the DC voltage source V in The positive terminal of the first inductor L1 is connected to the first terminal of the first capacitor C1; the second terminal of the first inductor L1 is connected to the positive terminal of the first diode D1 and the drain of the first switch S1; the first terminal of the second inductor L2 is connected to the second terminal of the first capacitor C1 and the negative terminal of the first diode D1; the second terminal of the second inductor L2 is connected to the first terminal of the second capacitor C2, the drain of the second switch S2, and the positive terminal of the second diode D2; the source of the first switch S1 is connected to the source of the second switch S2; the second terminal of the second capacitor C2 is connected to the third... The cathode of diode D3 is connected to the anode of the fourth diode D4; the first terminal of the third capacitor C3 is connected to the cathode of the second diode D2 and the anode of the third diode D3; the second terminal of the third capacitor C3 is connected to the source of the first switch S1, the source of the second switch S2, and the cathode of the output load R0; the first terminal of the fourth capacitor C4 is connected to the cathode of the fourth diode D4 and the anode of the output load R0; the second terminal of the fourth capacitor C4 is connected to the cathode of the second diode D2, the anode of the third diode D3, and the third capacitor C3.

[0009] Optionally, the source of the first switch S1 is grounded.

[0010] Optionally, the second terminal of the third capacitor C3 is connected to ground.

[0011] Optionally, both the first switch S1 and the second switch S2 are MOSFET switches of model IRFP250.

[0012] Optionally, the capacitance of the first capacitor C1 is 22μF, and the capacitances of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 are all 47μF.

[0013] Optionally, the inductance of the first inductor L1 is 220μH and the inductance of the second inductor L2 is 880μH.

[0014] Optionally, the first diode D1 is of model STPS30H100CT.

[0015] Optionally, the second diode D2, the third diode D3, and the fourth diode D4 are model MUR1560.

[0016] Optionally, the DC voltage source V in The input voltage is 12V.

[0017] A control method for a non-isolated DC-DC converter based on switched capacitors and inductors includes the following steps:

[0018] Step 1: Turn on the first switch S1 and the second switch S2, wherein the duty cycle of the first switch S1 and the second switch S2 is 0.75; turn on the third diode D3, so that the first diode D1, the second diode D2 and the fourth diode D4 are in a reverse bias state; DC voltage source V in The first inductor L1 is charged, and simultaneously the first capacitor C1 charges the second inductor L2; the third capacitor C3 transfers energy to the second capacitor C2, and together with the fourth capacitor C4, transfers energy to the output load R0; this stage ends when the switching transistor drive signal disappears.

[0019] Step 2: The first switch S1 and the second switch S2 are turned off; the first diode D1, the second diode D2, and the fourth diode D4 are turned on; the third diode D3 is reverse biased; the first inductor L1 charges the first capacitor C1; the DC voltage source V... in The first inductor L1 and the second inductor L2 transfer energy to the output load R0; the second capacitor C2 discharges, and the third capacitor C3 and the fourth capacitor C4 charge; this stage ends when the switching transistor drive signal is issued.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention effectively improves voltage gain by combining the advantages of switched capacitors and switched inductors. It features low voltage stress and low current ripple. Furthermore, the inductor current change generates an induced voltage that resists current changes, thus storing energy during the conduction phase. Until the first and second switches are turned off, the inductor current does not jump, maintaining its original direction. During the turn-off phase, the inductor current begins to decrease, generating a back electromotive force, which further enhances voltage gain. Simultaneously, because this structure uses fewer components, the upper limit of the switching frequency is higher, and the inductor ripple current is lower. This invention uses a series capacitor between the DC voltage source and the output load, providing voltage isolation to the non-isolated DC-DC converter and improving reliability. The switched capacitor and switched inductor units are constructed using diodes, simplifying control. Compared to other converters, this invention has only two linear operating modes, simplifying operation. It also features low conduction losses, high converter efficiency, a simple circuit structure, and low cost.

[0022] Furthermore, MOSFET switches have advantages such as strong anti-interference capability, low drive power, high operating frequency, and small size. Using MOSFET switches can further meet the requirements of high efficiency and economy in converters. Attached Figure Description

[0023] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. In the drawings:

[0024] Figure 1 This is a topology diagram of a non-isolated DC-DC converter based on a switched capacitor and inductor in a specific embodiment of the present invention.

[0025] Figure 2 This is a theoretical waveform diagram within one switching cycle in a specific embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the first working mode in a specific embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the second working mode in a specific embodiment of the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the present invention provides a non-isolated DC-DC converter based on switched capacitors and inductors, comprising:

[0033] The first terminal of the first inductor L1 is connected to the DC voltage source V. in The positive terminal of the first inductor L1 is connected to the first terminal of the first capacitor C1; the second terminal of the first inductor L1 is connected to the positive terminal of the first diode D1 and the drain of the first switching transistor S1; the first terminal of the second inductor L2 is connected to the second terminal of the first capacitor C1 and the negative terminal of the first diode D1; the second terminal of the second inductor L2 is connected to the first terminal of the second capacitor C2, the drain of the second switching transistor S2, and the positive terminal of the second diode D2; the source of the first switching transistor S1 is connected to the source of the second switching transistor S2 and grounded; the second terminal of the second capacitor C2 is connected to the third diode... The negative terminal of diode D3 and the positive terminal of the fourth diode D4 are connected; the first terminal of the third capacitor C3 is connected to the negative terminal of the second diode D2 and the positive terminal of the third diode D3; the second terminal of the third capacitor C3 is connected to the source of the first switching transistor S1, the source of the second switching transistor S2, and the negative terminal of the output load, and grounded; the first terminal of the fourth capacitor C4 is connected to the negative terminal of the fourth diode D4 and the positive terminal of the output load R0; the second terminal of the fourth capacitor C4 is connected to the negative terminal of the second diode D2, the positive terminal of the third diode D3, and the third capacitor C3.

[0034] Specifically, both the first switch S1 and the second switch S2 are MOSFET switches of model IRFP250.

[0035] Specifically, the capacitance of the first capacitor C1 is 22μF, and the capacitances of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 are all 47μF.

[0036] Specifically, the inductance of the first inductor L1 is 220μH, and the inductance of the second inductor L2 is 880μH.

[0037] Specifically, the first diode D1 is model STPS30H100CT, and the second diode D2, the third diode D3, and the fourth diode D4 are model MUR1560.

[0038] Specifically, DC voltage source Vin The input voltage is 12V.

[0039] Example

[0040] The following is combined with Figures 1 to 4 The specific embodiments of the present invention will be further described below.

[0041] The present invention provides a control method for a non-isolated DC-DC converter based on switched capacitors and inductors, comprising the following steps:

[0042] Step 1: The first switch S1 and the second switch S2 are turned on, both with a duty cycle of 0.75; the third diode D3 is turned on, and the first diode D1, the second diode D2, and the fourth diode D4 are in reverse bias; the DC voltage source V... in The first inductor L1 is charged, and simultaneously the first capacitor C1 charges the second inductor L2; the third capacitor C3 transfers energy to the second capacitor C2, and together with the fourth capacitor C4, transfers energy to the output load R0; this stage ends when the switching transistor drive signal disappears.

[0043] Step 2: The first switch S1 and the second switch S2 are turned off; the first diode D1, the second diode D2, and the fourth diode D4 are turned on; the third diode D3 is reverse biased; the first inductor L1 charges the first capacitor C1; the DC voltage source V... in The first inductor L1 and the second inductor L2 transfer energy to the output load R0; the second capacitor C2 discharges, and the third capacitor C3 and the fourth capacitor C4 charge; this stage ends when the switching transistor drive signal is issued.

[0044] See Figure 3 This invention discloses a first operating mode of a non-isolated DC-DC converter based on switched capacitors and inductors. Corresponding to step 1, the first switch S1 and the second switch S2 are turned on, both with a duty cycle of 0.75; the third diode D3 is turned on, and the first diode D1, the second diode D2, and the fourth diode D4 are in a reverse bias state; the DC voltage source V... in The first inductor L1 is charged, and simultaneously the first capacitor C1 charges the second inductor L2; the third capacitor C3 transfers energy to the second capacitor C2, and together with the fourth capacitor C4, transfers energy to the output load R0; this stage ends when the switching transistor drive signal disappears.

[0045] See Figure 4This invention discloses a second operating mode of a non-isolated DC-DC converter based on switched capacitors and inductors. Corresponding to step 2, the first switch S1 and the second switch S2 are turned off, the first diode D1, the second diode D2, and the fourth diode D4 are turned on, and the third diode D3 is in a reverse bias state; the first inductor L1 charges the first capacitor C1; the DC voltage source V... in The first inductor L1 and the second inductor L2 transfer energy to the output load R0; the second capacitor C2 discharges, and the third capacitor C3 and the fourth capacitor C4 charge; this stage ends when the switching transistor drive signal is issued.

[0046] Unless otherwise specified, the equipment components involved in the above embodiments are all conventional equipment components, and the structural settings, working methods or control methods involved are all conventional settings, working methods or control methods in the art unless otherwise specified.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A non-isolated DC-DC converter based on switched capacitors and inductors, characterized in that, include: Direct-current voltage source V in , a first switch tube S1, a second switch tube S2, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and an output load R0; The first terminal of the first inductor L1 is connected to the DC voltage source V in The positive terminal of the first inductor L1 is connected to the first terminal of the first capacitor C1; the second terminal of the first inductor L1 is connected to the positive terminal of the first diode D1 and the drain of the first switch S1; the first terminal of the second inductor L2 is connected to the second terminal of the first capacitor C1 and the negative terminal of the first diode D1; the second terminal of the second inductor L2 is connected to the first terminal of the second capacitor C2, the drain of the second switch S2, and the positive terminal of the second diode D2; the source of the first switch S1 is connected to the source of the second switch S2; the second terminal of the second capacitor C2 is connected to the third... The cathode of diode D3 is connected to the anode of the fourth diode D4; the first terminal of the third capacitor C3 is connected to the cathode of the second diode D2 and the anode of the third diode D3; the second terminal of the third capacitor C3 is connected to the source of the first switch S1, the source of the second switch S2, and the cathode of the output load R0; the first terminal of the fourth capacitor C4 is connected to the cathode of the fourth diode D4 and the anode of the output load R0; the second terminal of the fourth capacitor C4 is connected to the cathode of the second diode D2, the anode of the third diode D3, and the third capacitor C3.

2. The non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The source of the first switching transistor S1 is connected to ground.

3. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The second terminal of the third capacitor C3 is connected to ground.

4. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The first switch S1 and the second switch S2 are both MOSFET switches of model IRFP250.

5. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The capacitance of the first capacitor C1 is 22μF, and the capacitances of the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 are all 47μF.

6. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The inductance of the first inductor L1 is 220μH, and the inductance of the second inductor L2 is 880μH.

7. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The first diode D1 is model STPS30H100CT.

8. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The second diode D2, the third diode D3, and the fourth diode D4 are model MUR1560.

9. A non-isolated DC-DC converter based on switched capacitors and inductors according to claim 1, characterized in that, The DC voltage source V in The input voltage is 12V.

10. A control method for a non-isolated DC-DC converter based on a switched capacitor and inductor according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Turn on the first switch S1 and the second switch S2, wherein the duty cycle of the first switch S1 and the second switch S2 is 0.75; turn on the third diode D3, so that the first diode D1, the second diode D2 and the fourth diode D4 are in a reverse bias state; DC voltage source V in The first inductor L1 is charged, and simultaneously the first capacitor C1 charges the second inductor L2; the third capacitor C3 transfers energy to the second capacitor C2, and together with the fourth capacitor C4, transfers energy to the output load R0; this stage ends when the switching transistor drive signal disappears. Step 2: The first switch S1 and the second switch S2 are turned off; the first diode D1, the second diode D2, and the fourth diode D4 are turned on; the third diode D3 is reverse biased; the first inductor L1 charges the first capacitor C1; the DC voltage source V... in The first inductor L1 and the second inductor L2 transfer energy to the output load R0; the second capacitor C2 discharges, and the third capacitor C3 and the fourth capacitor C4 charge; this stage ends when the switching transistor drive signal is issued.

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