Series-parallel four-mode wide-range LLC converter circuit

Abstract

The utility model relates to power electronic conversion technical field discloses a kind of series-parallel four-mode wide-range LLC converter circuit, including primary conversion unit and secondary conversion unit, primary conversion unit and secondary conversion unit are bridge type LLC conversion circuit;There is LLC transformer between primary conversion unit and secondary conversion unit, LLC transformer has multiple primary windings on primary conversion unit side, also has multiple secondary windings on secondary conversion unit side;There are both parallel circuit and series circuit between multiple primary windings, and there are switching mechanisms on parallel circuit and series circuit;There are both parallel circuit and series circuit between multiple secondary windings, and there are switching mechanisms on parallel circuit and series circuit.The utility model can realize primary and secondary bilateral synchronous reconstruction, solve the contradiction of wide range and high efficiency, provide high cost-effective solution for new energy, server power supply and other scenes needing wide voltage input, by topology innovation, on the basis of LLC inherent soft switching advantage, significantly expand the applicable boundary, represent the leading development direction of wide-range high-efficiency converter.

Description

Technical Field

[0001] This utility model relates to the field of power electronic conversion technology, and in particular to the field of LLC resonant converter topology technology. Background Technology

[0002] With breakthroughs in energy storage battery technology, battery capacities are increasing, leading to low-voltage, high-current cells becoming the market mainstream due to their cost-effectiveness. However, traditional LLC converters, limited by their fixed turns ratio, struggle to meet the demands of multiple voltage platforms such as 24V / 48V / 72V / 96V. Current technology employs cascaded converters to achieve wide-range voltage regulation, but this method suffers from significantly reduced efficiency (over 15%) and a significant increase in size (40%). Utility Model Content

[0003] The purpose of this invention is to provide a series-parallel four-mode wide-range LLC converter circuit to solve the problem of flexibly switching between the primary winding and the secondary winding in series high-gain mode and parallel low-gain mode.

[0004] To solve the above-mentioned technical problems, this utility model provides a series-parallel four-mode wide-range LLC converter circuit, including a primary converter unit and a secondary converter unit, both of which are bridge LLC converter circuits; an LLC transformer is connected between the primary and secondary converter units, with multiple primary windings on the primary converter unit side and multiple secondary windings on the secondary converter unit side; the multiple primary windings are connected in both parallel and series circuits, and both parallel and series circuits have switching mechanisms; the multiple secondary windings are also connected in both parallel and series circuits, and both parallel and series circuits have switching mechanisms.

[0005] Both the primary and secondary conversion units are full-bridge LLC conversion circuits.

[0006] The switching mechanism is a relay or a MOSFET.

[0007] The specifications of the multiple primary windings are consistent.

[0008] The specifications of the multiple secondary windings are consistent.

[0009] In the plurality of primary windings, each primary winding is sequentially connected to the connecting branch of the next primary winding, and is connected to the next primary winding and the opposite pole link by two branches respectively, with a switching mechanism connected in series on both branches.

[0010] In the plurality of secondary windings, each secondary winding is sequentially connected to the connecting branch of the next secondary winding, and is divided into two branches that connect the next secondary winding and the opposite pole link respectively, with a switching mechanism connected in series on each of the two branches.

[0011] The sequential connection can be either in ascending or descending order.

[0012] A resonant inductor is connected in series in the connection circuit of the primary conversion unit.

[0013] A resonant capacitor is connected in series in the connection circuit of the primary conversion unit.

[0014] Compared with the prior art, this utility model can realize synchronous reconfiguration of the primary and secondary sides, solve the contradiction between wide range and high efficiency, and provide a cost-effective solution for scenarios requiring wide voltage input, such as new energy and server power supplies. Through topological innovation, it significantly expands the applicable boundaries based on the inherent soft-switching advantages of LLC, and represents the cutting-edge development direction of wide-range high-efficiency converters.

[0015] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with the corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the implementation. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a connection diagram of at least one embodiment of the present invention; Figure 2 yes Figure 1 Connection diagram of the intermediate and primary transformation units; Figure 3 yes Figure 1 Connection diagram of the intermediate secondary transformation unit; Figure 4 This is a connection diagram of another embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this utility model. The embodiments can be combined with and referenced by each other without contradiction.

[0019] Example 1 like Figures 1 to 4 The circuit shown is a series-parallel four-mode wide-range LLC converter, including a primary converter unit and a secondary converter unit, both of which are bridge LLC converter circuits. An LLC transformer is connected between the primary and secondary converter units. The LLC transformer has multiple primary windings on the primary converter unit side and multiple secondary windings on the secondary converter unit side. The multiple primary windings are connected in both parallel and series circuits, and both parallel and series circuits have switching mechanisms. The multiple secondary windings are also connected in both parallel and series circuits, and both parallel and series circuits have switching mechanisms.

[0020] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent in this embodiment.

[0021] Example 2 Based on Example 1, both the primary conversion unit and the secondary conversion unit are full-bridge LLC conversion circuits.

[0022] Furthermore, the switching mechanism is a relay or a MOSFET.

[0023] Furthermore, the specifications of the multiple primary windings are consistent.

[0024] Furthermore, the specifications of the multiple secondary windings are consistent.

[0025] Furthermore, in the multiple primary windings, each primary winding is sequentially connected to the connecting branch of the next primary winding, and is connected to the next primary winding and the opposite pole link by two branches respectively, with a switching mechanism connected in series on both branches.

[0026] Furthermore, in the multiple secondary windings, each secondary winding is sequentially connected to the connection branch of the next secondary winding, and is divided into two branches that connect the next secondary winding and the opposite pole link respectively, with a switching mechanism connected in series on both branches.

[0027] Furthermore, the connections are sequential, including both ascending and descending orders.

[0028] Furthermore, a resonant inductor is connected in series in the connection circuit of the primary conversion unit.

[0029] Furthermore, a resonant capacitor is connected in series in the connection circuit of the primary conversion unit.

[0030] Example 3 Based on the above embodiments, such as Figures 1 to 3 As shown, it includes an LLC resonant converter, a primary converter unit, and a secondary converter unit. The primary converter unit is a bridge circuit, consisting of four MOSFETs connected in series with a resonant inductor Lr and a resonant capacitor Cr. The secondary converter unit is a bridge circuit, consisting of four MOSFETs.

[0031] The LLC resonant converter consists of an LLC transformer and eight relays. By combining different combinations of closing and opening the relays, different modes are entered, achieving the effects of voltage gain and current regulation. ① Primary series, secondary series mode: Relays RY2, RY3, RY6, and RY7 are closed, while RY1, RY4, RY5, and RY8 are open. In this configuration, both the primary and secondary windings are connected in series. The effect is that the turns ratio remains unchanged, but the secondary rated load (output-side carrying capacity) doubles. This is suitable for scenarios where the original turns ratio needs to be maintained but the output power stability needs to be enhanced, such as powering high-load equipment.

[0032] ② Parallel connection of primary windings and series connection of secondary windings: Relays RY2, RY3, RY5, and RY8 are closed, while RY1, RY4, RY6, and RY7 are open. This doubles the turns ratio (increases the output voltage) and doubles the secondary rated load. This is suitable for applications requiring high voltage output and high-voltage energy storage batteries.

[0033] ③ Primary series, secondary parallel mode: Relays RY1, RY4, RY6, and RY7 are closed, while RY2, RY3, RY5, and RY8 are open. Effect: The turns ratio is halved (output voltage decreases), but the secondary rated load is doubled. This is suitable for environments with low voltage and high current requirements, such as large-capacity low-voltage batteries.

[0034] ④ Primary and secondary parallel connection mode: Relays RY1, RY4, RY5, and RY8 are closed, while RY2, RY3, RY6, and RY7 are open. Both the primary and secondary windings are connected in parallel. The effect is that the turns ratio remains constant, while the secondary rated load doubles. This mode provides balanced output characteristics and is suitable for efficient operation under standard loads, such as conventional power systems.

[0035] Example 4 Based on Examples 1 and 2, and largely the same as Example 3, such as... Figure 4 As shown, there are three primary windings and three secondary windings. Referring to Embodiment 3, based on the basic design of Embodiments 1 and 2, more primary windings and secondary windings can also be flexibly controlled and adjusted in series and parallel modes in the manner of Embodiment 3. Since its operating principle is basically the same as that of Embodiment 3, it will not be described again.

[0036] Therefore, this invention employs multi-winding transformers in both the primary and secondary windings. A switching mechanism (relay / MOSFET) dynamically switches the windings between series (high-gain mode) and parallel (low-gain mode), creating multiple operating mode combinations. This allows for topology reconstruction to achieve stepped gain expansion, avoiding efficiency degradation due to excessive deviation from the resonant frequency. For low-voltage scenarios, parallel windings effectively reduce equivalent impedance, decrease resonant network return power, and maintain ZVS soft-switching characteristics. For high-voltage scenarios, series windings effectively increase gain, avoiding the surge in conduction losses caused by insufficient magnetizing inductance in traditional LLC circuits. Overall, integrating multiple windings into a single transformer effectively eliminates the need for additional power stages, significantly reducing component cost and size, simplifying magnetic component design and parameter optimization, and avoiding the trade-offs in resonant cavity parameters required by traditional wide-gain LLC circuits.

[0037] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A series parallel four-mode wide range LLC converter circuit, characterized by: It includes a primary converter unit and a secondary converter unit, both of which are bridge LLC converter circuits. An LLC transformer is connected between the primary and secondary converter units. The LLC transformer has multiple primary windings on the primary converter unit side and multiple secondary windings on the secondary converter unit side. The multiple primary windings are connected in both parallel and series circuits, and there are switching mechanisms on both parallel and series circuits. The multiple secondary windings are also connected in both parallel and series circuits, and there are switching mechanisms on both parallel and series circuits.

2. The series parallel four-mode wide-range LLC converter circuit of claim 1, wherein: Both the primary and secondary conversion units are full-bridge LLC conversion circuits.

3. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: The switching mechanism is a relay or a MOSFET.

4. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: The specifications of the multiple primary windings are consistent.

5. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: The specifications of the multiple secondary windings are consistent.

6. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: In the plurality of primary windings, each primary winding is sequentially connected to the connecting branch of the next primary winding, and is connected to the next primary winding and the opposite pole link by two branches respectively, with a switching mechanism connected in series on both branches.

7. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: In the plurality of secondary windings, each secondary winding is sequentially connected to the connecting branch of the next secondary winding, and is divided into two branches that connect the next secondary winding and the opposite pole link respectively, with a switching mechanism connected in series on each of the two branches.

8. The series-parallel four-mode wide-range LLC converter circuit as described in claim 6 or 7, characterized in that: The sequential connection can be either in ascending or descending order.

9. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: A resonant inductor is connected in series in the connection circuit of the primary conversion unit.

10. The series-parallel four-mode wide-range LLC converter circuit as described in claim 1, characterized in that: A resonant capacitor is connected in series in the connection circuit of the primary conversion unit.

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