Isolated power converter
By using an auxiliary switch tube in an isolated power converter to control the transformer ratio and setting up an active clamp circuit in the primary unit, the problem of low efficiency of power converters within a wide input voltage range in the prior art is solved, and the problem of low efficiency of power converters in a wide input voltage range is realized. High efficiency and low cost power conversion.
Patent Information
- Application Number
- CN202411605860.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2024-12-17
AI Technical Summary
Existing power converters cannot achieve high efficiency over a wide input voltage range, especially when AC input voltages are below 90V or above 265V, making it difficult to maintain efficient operation.
By using an auxiliary switch tube in an isolated power converter to control the transformer ratio and installing an active clamp circuit in the primary unit to achieve zero voltage opening and leakage inductance energy recovery of the main switch tube, reducing switching losses.
Achieve high-efficiency power conversion over a wide voltage input range, reducing cost and volume and improving power density.
Smart Images
Figure CN119154683A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of switching power supplies, and in particular to an isolated power converter. Background Art
[0002] With the extensive application of switching power supplies, the requirements for them are also constantly increasing, requiring switching power supplies to have the characteristics of low cost, high efficiency, high power density and high reliability.
[0003] Among switching power supplies, offline switching power supplies are widely used in mobile phone chargers, laptop chargers, and computer power supplies. To adapt to the two power specifications of AC 110V and 220V, offline switching power supplies are generally designed for AC 90V~265V input. In some cases where the working conditions are more severe, when the AC input voltage is lower than 90V or higher than 265V, the switching power supply is still required to work. However, current power converters cannot achieve high efficiency in a wide input range. Summary of the invention
[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides an isolated power converter.
[0005] In order to achieve the above purpose, the technical solution of the present invention is as follows:
[0006] In an embodiment of the present disclosure, an isolated power converter is provided, including a primary side connected to an input end and a secondary side connected to an output end, wherein: the primary side includes a transformer leakage inductance, a plurality of primary side units, and an auxiliary switch tube connected between two primary side units; the power converter ratio is changed by controlling the opening and closing of the auxiliary switch tube.
[0007] In the disclosed embodiment, the auxiliary switch tube is selected from a MOS tube, a triode, and an IGBT switch tube.
[0008] In the embodiment of the present disclosure, each of the primary units includes a primary winding of a transformer and a main switch tube.
[0009] In the disclosed embodiment, the main switch tube is selected from MOS tube, triode, and IGBT switch tube.
[0010] In the embodiment of the present disclosure, an active clamping circuit is also provided on the primary side and is configured to achieve zero voltage turn-on of the main switch in the primary side unit and leakage inductance energy recovery.
[0011] In the disclosed embodiment, the primary side is further provided with a plurality of active clamping circuits, each of the primary side units is provided with an independent active clamping circuit, and is configured to realize zero voltage turn-on of the main switch in the primary side unit and leakage inductance energy recovery.
[0012] In the embodiment of the present disclosure, a shared active clamping circuit is further provided on the primary side, and the shared active clamping circuit is configured to achieve zero voltage turn-on of the main switch in any primary side unit and leakage inductance energy recovery.
[0013] In the embodiment of the present disclosure, the shared active clamp circuit is arranged before the first primary unit, or the shared active clamp circuit is arranged after the last primary unit.
[0014] In the embodiment of the present disclosure, the active clamping circuit includes an active clamping switch tube and an active clamping capacitor. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:
[0016] Figure 1 A schematic diagram of the circuit principle of an active clamp flyback converter in the prior art is shown;
[0017] Figure 2 A schematic diagram of the circuit principle of the isolated power converter according to Embodiment 1 of the present disclosure is shown.
[0018] Figure 3 A circuit schematic diagram of an isolated power converter according to Embodiment 2 of the present disclosure is shown.
[0019] Figure 4 A schematic diagram of the circuit principle of an isolated power converter according to Embodiment 3 of the present disclosure is shown.
[0020] Figure 5 A circuit schematic diagram of an isolated power converter according to Embodiment 4 of the present disclosure is shown.
[0021] Lr: Transformer leakage inductance;
[0022] Lp1, Lp2 … Lpn: primary winding of transformer;
[0023] Ls: secondary winding of transformer;
[0024] S a1 , S a2 … S an : Auxiliary switch tube;
[0025] S ac1 , S ac2 … S acn : Active clamp switch tube;
[0026] S1, S2, ... S n : Main switch tube;
[0027] S R : Secondary side switch tube. DETAILED DESCRIPTION
[0028] The present disclosure provides an isolated power converter, which can achieve high efficiency within a wide voltage input range by controlling the opening and closing of auxiliary switch tubes and selecting a suitable transformer ratio under wide voltage input conditions; and by setting an active clamping circuit, zero voltage switching of all main switch tubes is achieved.
[0029] Isolated power converters are mainly divided into forward converters, flyback converters, push-pull converters, half-bridge power converters, full-bridge power converters and various resonant converters (such as LLC resonant converters, LCC resonant converters and LCLC resonant converters, etc.). Taking into account factors such as cost, input voltage range, efficiency and power density, active clamp flyback converters are currently widely used in applications such as mobile phone chargers, laptop chargers and computer power supplies. The circuit schematic diagram is shown below. Figure 1 As shown, where L r is the transformer leakage inductance, n p1 is the primary side of the transformer, L s is the transformer secondary, L m is the transformer excitation inductance, S1 is the transformer main switch tube, S a For auxiliary switch tube, S R It is a synchronous rectifier switch. c is an active clamping capacitor. Through the application of the active clamping circuit, the flyback converter can achieve zero voltage turn-on of the main switch tube (S1) and at the same time achieve L r Energy recovery improves the efficiency of the power converter. However, in the process of realizing the present invention, the inventors found that the above-mentioned prior art has the following technical defects: it is impossible to achieve high efficiency of the power converter within a wide range of input voltage. For example, in an offline application with an AC input of 90V~265V, when the AC input voltage is lower than 90V or higher than 265V in some more severe working conditions, the switching power supply is still required to work. Therefore, the wide range of AC voltage input causes the input voltage range of the active clamped flyback converter to be wide. Since the active clamped flyback converter adopts pulse width modulation, the wide input range causes a large duty cycle conversion range, so that the converter cannot achieve high efficiency within a wide input range. Therefore, the present disclosure provides an isolated power converter.
[0030] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.
[0031] In the first embodiment of the present disclosure, an isolated power converter is provided, Figure 2-Figure 5 As shown, the power converter includes a primary side connected to an input terminal and a secondary side connected to an output terminal, wherein:
[0032] The primary side includes a transformer leakage inductance, a plurality of primary side units, and an auxiliary switch tube connected between two primary side units; the power converter ratio is changed by controlling the on and off of the auxiliary switch tube.
[0033] Specific as Figure 2 As shown, the isolated power converter includes n primary sides, n>2, and a secondary side. The primary side of the transformer is connected to the auxiliary switch tube (S a1 , S a2 … S an ) connection. Under wide input voltage conditions, by controlling the on and off of the auxiliary switch tube, the transformer ratio can be changed, thereby achieving high efficiency over a wide input voltage range. It should be noted that since there is no active clamping circuit, the main switch tubes (S1, S2…S n ) cannot achieve zero voltage turn-on, and cannot realize leakage inductance energy recovery, thus increasing switching loss and loss caused by leakage inductance. In practical applications, in order to achieve zero voltage turn-on of the main switch tube and leakage inductance energy recovery, an active clamping circuit needs to be added.
[0034] In the embodiment of the present disclosure, the primary side is also provided with an active clamping circuit, and is configured to realize zero voltage turn-on of the main switch in the primary side unit and leakage inductance energy recovery. For example, each primary side unit is provided with an independent active clamping circuit, or all primary side units share an active clamping circuit.
[0035] Specifically, in Embodiment 2 of the present disclosure, Figure 3 As shown in the figure, the isolated power converter includes n primary sides and one secondary side. The primary side of the transformer is connected to the auxiliary switch tube (S a1 , S a2 … S an ) connection, which is different from Example 1 in that each main switch tube has a corresponding active clamping circuit, so that the main switch tube can be turned on at zero voltage and leakage inductance energy can be recovered. Since each main switch tube has a corresponding active clamping circuit, the circuit structure is somewhat complicated, the number of components is large, and the cost is somewhat high.
[0036] Therefore, it is proposed Figure 4 In the embodiment 3 of the present disclosure, as shown in FIG. Figure 4 As shown in the figure, the isolated power converter includes n primary sides and one secondary side. The primary side of the transformer is connected to the auxiliary switch tube (S a1 , S a2 … S an) are connected, and when the design is optimized, the transformer ratio can be controlled by controlling the on and off of the auxiliary switch tube under different input voltage conditions. Different from Example 2, in Example 3, only one shared active clamping circuit is arranged before the first primary unit to achieve zero voltage switching of all main switch tubes, and at the same time, the leakage inductance energy can be recovered.
[0037] In Embodiment 4 of the present disclosure, Figure 5 As shown in the figure, the isolated power converter includes n primary sides and one secondary side. The primary side of the transformer is connected to the auxiliary switch tube (S a1 , S a2 … S an ) connection, when optimizing the design, the transformer ratio can be controlled by controlling the conduction and shutdown of the auxiliary switch tube under different input voltage conditions. The principles of embodiment 3 and embodiment 4 are the same, and both can realize the zero voltage turn-on of any main switch tube, and at the same time can recover the energy of leakage inductance. The difference is that the position of the shared active clamping circuit is located after the last group of primary sides in embodiment 4.
[0038] According to an embodiment of the present disclosure, the auxiliary switch tube and the main switch tube may be selected from MOS tubes, triodes, IGBT switch tubes, or other types of switch tubes.
[0039] According to an embodiment of the present disclosure, each of the primary units includes a primary winding of a transformer and a main switch tube.
[0040] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.
[0041] According to the above description, those skilled in the art should have a clear understanding of the isolated power converter disclosed in the present invention.
[0042] In summary, the present disclosure provides an isolated power converter, which can achieve high efficiency in a wide voltage input range by controlling the selection of a suitable transformer ratio through the opening and closing of an auxiliary switch tube under wide voltage input conditions; and can achieve zero voltage switching of all main switch tubes through a set of active clamping circuits. All main switch tubes share a set of active clamping circuits, and the sharing of active clamping circuits reduces costs, reduces volume, and improves power density.
[0043] It should be noted that, in this document, unless otherwise specified, “a” element is not limited to a single element, but may include one or more elements.
[0044] In addition, in this document, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple components with the same name, and do not indicate that there is a hierarchy, level, execution order, or process order between them. A "first" component and a "second" component may appear together in the same component, or appear in different components. The presence of a component with a larger ordinal number does not necessarily indicate the presence of another component with a smaller ordinal number.
[0045] In this document, unless otherwise specified, the so-called feature A "or" or "and / or" (and / or) feature B means that A exists alone, B exists alone, or A and B exist at the same time; the so-called feature A "and" (and) or "and" (and) or "and" (and) feature B means that A and B exist at the same time; the so-called "include", "comprise", "have" and "contain" mean including but not limited to these.
[0046] In addition, in this document, the terms "upper", "lower", "left", "right", "front", "back", or "between" are only used to describe the relative positions between multiple elements, and can be extended to include translation, rotation, or mirroring. In addition, in this document, unless otherwise specified, "an element is on another element" or similar descriptions do not necessarily mean that the element contacts the other element.
[0047] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.
[0048] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.
Claims
1. An isolated power converter, comprising a primary side connected to an input terminal and a secondary side connected to an output terminal, wherein: The primary side includes a transformer leakage inductance, a plurality of primary side units, and an auxiliary switch tube connected between two primary side units; the power converter ratio is changed by controlling the on and off of the auxiliary switch tube.
2. The isolated power converter according to claim 1, wherein the auxiliary switch tube is selected from a MOS tube, a triode, and an IGBT switch tube. 3 . The isolated power converter according to claim 1 , wherein each of the primary units comprises a primary winding of a transformer and a main switch tube. 4 . The isolated power converter according to claim 3 , wherein the main switch tube is selected from a MOS tube, a triode, and an IGBT switch tube.
5. The isolated power converter according to any one of claims 1 to 4, wherein the primary side is further provided with an active clamping circuit, and is configured to achieve zero voltage turn-on of the main switch in the primary side unit and leakage inductance energy recovery.
6. According to the isolated power converter according to any one of claims 1-4, the primary side is also provided with a plurality of active clamping circuits, each of the primary side units is provided with an independent active clamping circuit, and is configured to achieve zero voltage turn-on of the main switch in the primary side unit and leakage inductance energy recovery.
7. According to the isolated power converter according to any one of claims 1 to 4, the primary side is further provided with a shared active clamping circuit, and the shared active clamping circuit is configured to achieve zero voltage turn-on and leakage inductance energy recovery of the main switch in any primary side unit. 8 . The isolated power converter according to claim 7 , wherein the shared active clamp circuit is arranged before the first primary unit. 9 . The isolated power converter according to claim 7 , wherein the shared active clamp circuit is arranged after the last primary unit. 10 . The isolated power converter according to claim 5 , wherein the active clamping circuit comprises an active clamping switch tube and an active clamping capacitor.