Non-isolated quadratic Boost converter

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By introducing switched capacitors and inductors into the Boost converter, the structure of the non-isolated quadratic Boost converter is optimized, solving the problem of low boost ratio in traditional Boost converters. This achieves high voltage gain and low device stress, making it suitable for new energy power generation systems.

CN223978578UActive Publication Date: 2026-03-06SICHUAN UNIV JINCHENG INST

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Patent Information

Application Number: CN202422788301.7
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-11-15
Publication Date: 2026-03-06
Estimated Expiration: 2034-11-15

AI Technical Summary

Technical Problem

Traditional Boost converters have low boost ratios, making it difficult to meet DC bus voltage requirements in new energy power generation systems. Furthermore, increased device current and voltage stress reduces transmission efficiency.

Method used

By introducing switched capacitor units and switched inductor units, the converter structure is optimized. A single-switch structure is adopted, including capacitors Ca and Cb, diodes Da and Db, and inductors Lb and Lc. Some diodes are replaced to form a non-isolated quadratic Boost converter.

Benefits of technology

It achieves high voltage gain, reduces device stress, has a simple structure, low cost, and is easy to adjust, making it suitable for new energy power generation systems.

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Abstract

The utility model discloses a non-isolated quadratic Boost converter, which solves the technical problem of low step-up ratio characteristic of the existing converter. The non-isolated secondary Boost converter comprises a main loop which comprises a power supply, an inductor La, a switching tube S, a diode Dc, a diode Df, a load resistor R and a capacitor Cd; one end of the inductor La is connected with the positive electrode of the power supply, and the other end is connected with the negative electrode of the power supply after being divided into a first branch and a second branch which are connected in parallel; the diode Dc and the switch tube S are sequentially arranged on the first branch; the diode Df, the load resistor R and the capacitor Cd are arranged on the second branch; the switched capacitor unit comprises a capacitor Ca, a capacitor Cb, a diode Da and a diode Db; the switched capacitor unit is connected with the first branch circuit, the second branch circuit and the power supply cathode; the switch inductor-capacitor unit comprises a capacitor Cc, a diode Dd, a diode De, an inductor Lb and an inductor Lc; the switched inductor-capacitor unit is connected with the first branch, the second branch and the switched capacitor unit; the number of the switch tube S is one.

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Description

Technical Field

[0001] This utility model relates to the technical field of voltage boost transformers, and more specifically, to a non-isolated secondary boost converter. Background Technology

[0002] Currently, the output voltage of new energy power generation systems is relatively low, making it difficult to meet the DC bus voltage requirements. For example, in applications such as electric vehicles, microgrids, and communications, the output voltage of new energy power generation systems such as photovoltaics and batteries typically ranges from 12V to 48V, while the DC bus output voltage should be at least 380V. Boost converter technology provides an effective solution to these problems, and the attention and demand for boost converters are increasing daily.

[0003] A boost converter, also known as a step-up converter, is a DC-DC power converter with an input voltage lower than its output voltage. Among various types of boost converters, non-isolated boost converters have attracted considerable attention due to their relatively low size, losses, and cost. Although theoretically, the voltage gain of a boost converter can approach infinity when the duty cycle is close to 1, the current and voltage stress on the converter devices gradually increases with the increase of the duty cycle, leading to more power losses and reduced transmission efficiency. Therefore, the low boost ratio characteristic of traditional boost converters limits their practicality. Utility Model Content

[0004] The main objective of this invention is to provide a non-isolated quadratic Boost converter to solve the technical problem of low boost ratio characteristics in traditional Boost converters in the prior art.

[0005] To achieve the above objectives, this utility model provides a non-isolated quadratic Boost converter, the technical solution of which is as follows:

[0006] Non-isolated quadratic Boost converters include:

[0007] The main circuit includes a power supply, an inductor La, a switching transistor S, a diode Dc, a diode Df, a load resistor R, and a capacitor Cd. One end of the inductor La is connected to the positive terminal of the power supply, and the other end is divided into a first branch and a second branch in parallel before being connected to the negative terminal of the power supply. The diode Dc and the switching transistor S are arranged sequentially on the first branch. The diode Df, the load resistor R, and the capacitor Cd are arranged on the second branch. The positive terminal of the diode Df is connected to the inductor La, and the load resistor R and the capacitor Cd are connected in parallel and then connected to the negative terminal of the diode Df.

[0008] The switched capacitor unit includes capacitor Ca, capacitor Cb, diode Da, and diode Db; the switched capacitor unit is connected to the first branch, the second branch, and the negative terminal of the power supply.

[0009] A switching inductor-capacitor unit includes a capacitor Cc, a diode Dd, a diode De, an inductor Lb, and an inductor Lc; the switching inductor-capacitor unit is connected to the first branch, the second branch, and the switching capacitor unit;

[0010] The number of switching transistors S is 1.

[0011] This invention introduces a switched capacitor unit (consisting of 2 capacitors and 2 diodes) and a switched capacitor-inductor unit (which replaces one diode in the topology of the switched inductor unit with a capacitor, i.e., consists of 2 inductors, 2 diodes and 1 capacitor) on the basis of the traditional quadratic Boost converter, resulting in an improved non-isolated quadratic Boost converter. The advantages are: (1) It has only 15 devices, with simple structure, low cost and convenient adjustment; (2) It has high voltage gain and low device stress, and high boost ratio; (3) It adopts a single-switch structure, and the control mode is very simple; (4) The input current is continuous, and the input terminal and the load terminal share the ground facilities.

[0012] As a further improvement to the aforementioned non-isolated quadratic Boost converter: in the switched capacitor unit:

[0013] Capacitor Cb is located in the second branch between inductor La and diode Df, and the negative terminal of capacitor Cb is connected to inductor La;

[0014] The positive terminal of diode Da is connected to the negative terminal of inductor La or capacitor Cb; the negative terminal of diode Da is connected to the positive terminal of diode Db; and the negative terminal of diode Db is connected to the positive terminal of capacitor Cb.

[0015] The negative terminal of capacitor Ca is connected to the negative terminal of diode Da or the positive terminal of diode Db, and the positive terminal of capacitor Ca is connected to the negative terminal of the power supply.

[0016] As a further improvement to the aforementioned non-isolated quadratic Boost converter: in the switched inductor-capacitor unit:

[0017] Inductor Lb and diode De are sequentially arranged in the second branch between capacitor Cb and diode Df; one end of inductor Lb is connected to the positive terminal of capacitor Cb, and the other end is connected to the positive terminal of diode De; the negative terminal of diode De is connected to the positive terminal of diode Df.

[0018] The negative terminal of capacitor Cc is connected to the negative terminal of diode Db or the positive terminal of capacitor Cb; the positive terminal of diode Dd is connected to the positive terminal of inductor Lb or diode De; and the negative terminal of diode Dd is connected to the positive terminal of capacitor Cc.

[0019] One end of the inductor Lc is connected to the negative terminal of the diode Dd or the positive terminal of the capacitor Cc, and the other end is connected to the switching transistor S or the negative terminal of the diode Dc, as well as to the negative terminal of the diode De or the positive terminal of the diode Df.

[0020] Therefore, it can be seen that the non-isolated quadratic Boost converter of this utility model has successfully optimized the performance of the converter by introducing switched capacitor technology and switched inductor technology. It can reduce the voltage stress on the components while obtaining higher voltage gain. Moreover, it has a simple structure, low cost, and convenient adjustment. It effectively solves the technical problem of low boost ratio characteristics of traditional Boost converters in the prior art and has good practicality.

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. Attached Figure Description

[0022] The accompanying drawings, which form part of this utility model, are used to aid in understanding this utility model. The content provided in the drawings and the related descriptions in this utility model can be used to explain this utility model, but do not constitute an undue limitation of this utility model. In the drawings:

[0023] Figure 1 This is a topology diagram of an embodiment of the non-isolated quadratic Boost converter of this utility model.

[0024] Figure 2 The voltage gain diagrams of the non-isolated quadratic Boost converter of this invention are shown at different duty cycles.

[0025] Figure 3 This represents the minimum stress of the switching transistor S under different voltage gains.

[0026] Figure 4 This represents the minimum stress of the device under different voltage gains.

[0027] Figure 5 This represents the minimum stress of a diode under different voltage gains. Detailed Implementation

[0028] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0029] The technical solutions and features provided in the various parts of this utility model, including the following description, can be combined with each other without conflict.

[0030] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0031] Regarding the terminology and units used in this utility model: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this utility model are intended to cover non-exclusive inclusion.

[0032] Figure 1 This is a topology diagram of an embodiment of the non-isolated quadratic Boost converter of this utility model.

[0033] like Figure 1 The non-isolated secondary boost converter shown includes a main circuit, a switched capacitor unit, and a switched inductor-capacitor unit. The main circuit includes a power supply, inductor La, switch S, diode Dc, diode Df, load resistor R, and capacitor Cd. The switched capacitor unit includes capacitors Ca and Cb, diodes Da and Db. The switched inductor-capacitor unit includes capacitor Cc, diode Dd, diode De, inductor Lb, and inductor Lc.

[0034] In the main circuit, one end of the inductor La is connected to the positive terminal of the power supply, and the other end is divided into the first branch and the second branch in parallel before being connected to the negative terminal of the power supply; the diode Dc and the switching transistor S are arranged in the first branch in sequence; the diode Df, the load resistor R and the capacitor Cd are arranged in the second branch, the positive terminal of the diode Df is connected to the inductor La, and the load resistor R and the capacitor Cd are connected in parallel and then connected to the negative terminal of the diode Df.

[0035] In the switched capacitor unit, capacitor Cb is located on the second branch between inductor La and diode Df, with the negative terminal of capacitor Cb connected to inductor La; the positive terminal of diode Da is connected to inductor La or the negative terminal of capacitor Cb, the negative terminal of diode Da is connected to the positive terminal of diode Db, and the negative terminal of diode Db is connected to the positive terminal of capacitor Cb; the negative terminal of capacitor Ca is connected to the negative terminal of diode Da or the positive terminal of diode Db, and the positive terminal of capacitor Ca is connected to the negative terminal of the power supply.

[0036] In the switching inductor-capacitor unit, inductor Lb and diode De are sequentially arranged on the second branch between capacitor Cb and diode Df; one end of inductor Lb is connected to the positive terminal of capacitor Cb, and the other end is connected to the positive terminal of diode De; the negative terminal of diode De is connected to the positive terminal of diode Df; the negative terminal of capacitor Cc is connected to the negative terminal of diode Db or the positive terminal of capacitor Cb, the positive terminal of diode Dd is connected to inductor Lb or the positive terminal of diode De, and the negative terminal of diode Dd is connected to the positive terminal of capacitor Cc; one end of inductor Lc is connected to the negative terminal of diode Dd or the positive terminal of capacitor Cc, and the other end is connected to the switching transistor S or the negative terminal of diode Dc, as well as to the negative terminal of diode De or the positive terminal of diode Df.

[0037] There is one switching transistor S. Therefore, within one working cycle, there are two operating modes for switching transistor S: on and off, as follows:

[0038] When the switching transistor S is turned on, diodes Da, Dd, and Df are cut off due to reverse voltage drop, while diodes Db, Dc, and De are turned on due to forward voltage drop. The power supply charges inductor La, capacitor Ca charges capacitor Cb, capacitor Ca charges inductor Lb, and capacitors Ca and Cc in series charge inductor Lc. The load resistor R is powered by capacitor Cd. The inductor current waveform shows a linear upward trend. This process includes:

[0039]

[0040] When switch S is turned off, diodes Db, Dc, and De are cut off due to reverse voltage drop, while diodes Da, Dd, and Df are turned on due to forward voltage drop. The power supply and inductor La charge capacitor Ca, inductor Lb charges capacitor Cc, and the power supply, inductor La, inductor Lc, capacitor Cb, and capacitor Cc charge capacitor Cd. The load resistor R is powered by capacitor Cd. The inductor current waveform shows a linear decreasing trend. This process includes:

[0041]

[0042] The voltage gain M (voltage boost ratio) is calculated as follows:

[0043] In a complete period T s According to the volt-second balance principle of inductors, we can obtain:

[0044]

[0045] From equation (3), the voltage stress equations for each capacitor can be obtained as follows:

[0046]

[0047] The voltage gain M of the converter can be calculated using equations (3) and (4) as follows:

[0048]

[0049] Therefore, the expression for calculating the final output voltage of the proposed converter is:

[0050]

[0051] The calculation methods for voltage stress and current stress are as follows:

[0052] The formulas for calculating the voltage stress of the switching transistor S and each diode are as follows:

[0053]

[0054] Based on the capacitor ampere-second balance principle, the calculation expression for the current stress of each diode can be obtained as follows:

[0055]

[0056] The formula for calculating the current stress of the capacitor under both the on and off operating modes of the switching transistor S can be obtained as follows:

[0057]

[0058] The average current I flowing through switch S during the conduction phase of switch S is ds The calculation expression is:

[0059]

[0060] In the above expression:

[0061] t is time; H is duty cycle; V i V is the input voltage. o Vs is the output voltage; I is the voltage across the switch S. o For output current;

[0062] V Cx For capacitor C x The voltage across the terminals, I Cx For capacitor C x The current on C Cx For capacitor C x The capacitance values are given by x = a, b, c, d.

[0063] V Dy For diode D y The voltage across the terminals, I Dy For diode D y The current in the circuit is y = a, b, c, d, e, f;

[0064] I Lz For inductor L z The current on, i Lz For inductor L z Current stress on, L Lz For inductor L z The inductance values are z = a, b, c.

[0065] The performance of the non-isolated quadratic Boost converter described above was determined through experiments and calculations as follows:

[0066] Figure 2 This diagram shows the voltage gain of the non-isolated quadratic Boost converter of this invention at different duty cycles. Figure 2 As shown, under common operating conditions with duty cycles of 0.4, 0.5, and 0.6, the voltage gain can reach 6.29, 10, and 18.13, respectively, indicating that the converter of this invention has high voltage gain and can effectively achieve voltage boost.

[0067] Figure 3 This represents the minimum stress of the switching transistor S under different voltage gains. Figure 4 This represents the minimum stress of the device under different voltage gains. Figure 5 This represents the minimum stress on a diode under different voltage gains. For example... Figure 3-5 As shown, the converter of this invention has the advantage of low device stress.

[0068] The foregoing has described the relevant content of this utility model. Those skilled in the art will be able to implement this utility model based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of this utility model without inventive effort should fall within the protection scope of this utility model.

Claims

1. A non-isolated secondary-side boost converter, characterized by: The utility model relates to a kind of switching power supply, including: Main circuit, including power supply, inductor La, switch tube S, diode Dc, diode Df, load resistance R and capacitor Cd;One end of inductor La is connected with power supply anode, the other end is divided into parallel first branch and second branch and then is connected with power supply cathode;Diode Dc and switch tube S are sequentially arranged on first branch;Diode Df, load resistance R and capacitor Cd are arranged on second branch, diode Df anode is connected with inductor La, load resistance R and capacitor Cd are connected with diode Df cathode after being connected in parallel; Switching capacitor unit, including capacitor Ca, capacitor Cb, diode Da and diode Db;The switching capacitor unit is connected with first branch, second branch and power supply cathode; Switching inductance-capacitance unit, including capacitor Cc, diode Dd, diode De, inductor Lb and inductor Lc;The switching inductance-capacitance unit is connected with first branch, second branch and switching capacitor unit; The number of switch tube S is 1.

2. The non-isolated secondary-side boost converter of claim 1, wherein: In switching capacitor unit: Capacitor Cb is arranged on second branch between inductor La and diode Df, and capacitor Cb cathode is connected with inductor La; Diode Da anode is connected with inductor La or capacitor Cb cathode, diode Da cathode is connected with diode Db anode, and diode Db cathode is connected with capacitor Cb anode; Capacitor Ca cathode is connected with diode Da cathode or diode Db anode, and capacitor Ca anode is connected with power supply cathode.

3. The non-isolated secondary-side boost converter of claim 2, wherein: In switching inductance-capacitance unit: Inductor Lb and diode De are sequentially arranged on second branch between capacitor Cb and diode Df;One end of inductor Lb is connected with capacitor Cb anode, and the other end is connected with diode De anode;Diode De cathode is connected with diode Df anode; Capacitor Cc cathode is connected with diode Db cathode or capacitor Cb anode, diode Dd anode is connected with inductor Lb or diode De anode, and diode Dd cathode is connected with capacitor Cc anode; One end of inductor Lc is connected with diode Dd cathode or capacitor Cc anode, and the other end is connected with switch tube S or diode Dc cathode and diode De cathode or diode Df anode.