A multi-stage wireless power supply coupling transformer

Abstract

The application provides a multi-stage wireless power supply coupling transformer, and relates to the technical field of power electronics, and comprises a plurality of stages of transformer modules connected in sequence, one stage of the transformer modules comprises one IGBT and one transformer connected in sequence, the transformer comprises an isolation coil, a power supply coil, a resonance capacitor, a core and a driving circuit, the core is wound with a first isolation coil and a second isolation coil from top to bottom on two longitudinal edges of the core, the first isolation coil and the second isolation coil are used to transmit electric energy of each stage, the core is wound with the power supply coil on one transverse edge of the core, the power supply coil is connected with the driving circuit, the driving circuit is connected with the IGBT and controls the conduction and the turn-off of the IGBT, compared with the traditional transformer, the multi-stage wireless power supply coupling transformer can realize multi-directional electric energy transmission, the resonance capacitor is added to eliminate leakage inductance, the compatibility is high, the volume is small, and the insulation strength of the coil increases with the increase of the stage number.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more particularly to a multi-stage wireless power supply coupling transformer. Background Technology

[0002] In the development of power electronics technology, some new types of semiconductor switches have emerged and been gradually applied to high-voltage fields. The Insulated Gate Bipolar Transistor (IGBT) is one such example. An IGBT is a composite, fully controllable, voltage-driven power semiconductor device composed of a BJT (Bipolar Junction Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It has advantages such as simple driving method, fast switching speed, and high voltage and current capacity. IGBTs are available in voltage ratings of 600V, 1200V, 1700V, 2500V, 3300V, 4500V, and 6500V. Different voltage ratings are used in different applications. To meet design requirements, even the highest voltage rating of 6500V cannot meet the needs of 10kV DC transmission. This necessitates connecting IGBTs of a certain voltage rating in series. Furthermore, the price of IGBTs increases with the voltage rating. In high-voltage motor drives and DC transmission, IGBTs are used in conjunction with transformers.

[0003] Traditional control modes combining a single transformer and a single IGBT are limited, and a single IGBT often faces the challenge of insufficient voltage withstand capability. To ensure reliable power supply, capacitor voltage divider is traditionally used. However, capacitor voltage divider suffers from the problem that no energy is stored in the capacitors when the main circuit loses power. Traditional multi-level transformers are not only bulky but also lack resonant capacitors to mitigate the effects of leakage inductance. Therefore, there is a need to invent a multi-stage coupled transformer that can increase magnetic flux by using parallel resonant capacitors to reduce leakage inductance in the coupling coils, resulting in a more stable and reliable power supply, and solving the problem of unstable power supply in the main circuit under voltage loss associated with capacitor voltage divider transformers. Summary of the Invention

[0004] To address the aforementioned technical problem of unstable power supply when the main circuit of a traditional transformer experiences voltage loss, this invention provides a multi-stage wireless power supply coupling transformer. This invention primarily employs a multi-stage series transformer configuration, where coils briefly store electrical energy, allowing multiple coils to work together to reduce voltage fluctuations and resolve the power supply instability issue.

[0005] The technical means employed in this invention are as follows:

[0006] A multi-stage wireless power supply coupling transformer includes: several stages of transformer modules connected in sequence. Each stage of the transformer module includes a connected IGBT and a transformer. The transformer includes a first isolation coil, a second isolation coil, a power supply coil, a first resonant capacitor, a second resonant capacitor, an iron core, and a drive circuit. The iron core is a ring-shaped square iron core used to constrain the electromagnetic path of the coil. The first isolation coil and the second isolation coil for transmitting power at each stage are wound from top to bottom on the two longitudinal sides of the iron core, respectively. The power supply coil for supplying power to the IGBT is wound on one transverse side of the iron core. The power supply coil is connected to the drive circuit, and the drive circuit is connected to the IGBT and controls the IGBT's on and off states.

[0007] Furthermore, the first isolation coil is connected to the second isolation coil in the previous stage transformer module, and the second isolation coil is connected to the first isolation coil in the next stage transformer module to realize wireless power transmission.

[0008] Furthermore, a first resonant capacitor is connected in parallel between the second isolation coil in the previous stage transformer module and the first isolation coil in the next stage transformer module. The power supply coil is connected in parallel with the second resonant capacitor. The first resonant capacitor is used to eliminate the leakage inductance generated by the first isolation coil and the second isolation coil, and the second resonant capacitor is used to eliminate the leakage inductance generated by the power supply coil.

[0009] Furthermore, the E stage of the IGBT is connected to the C stage of the IGBT in the next stage transformer module, and the C stage of the IGBT is connected to the E stage of the IGBT in the previous stage transformer module.

[0010] Furthermore, the IGBTs in each stage of the transformer module use the same specification.

[0011] Furthermore, the coil turns ratio of the first isolation coil to the second isolation coil between each stage is (n+1∶n), where n represents the stage number.

[0012] Furthermore, the number of turns of the first isolation coil in the previous stage and the second isolation coil in the next stage are the same.

[0013] Furthermore, within the same stage, the second isolation coil has the same number of turns as the power supply coil.

[0014] Furthermore, a rectifier diode for rectification is connected in series between the power supply coil and the drive circuit.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The present invention uses a square iron core to constrain the electromagnetic path of the coil, increase the magnetic flux flowing through the coil, thereby enhancing the induced electromotive force and improving the efficiency of the transformer.

[0017] This invention connects a first resonant capacitor in parallel with the isolation coil between adjacent modules. This first resonant capacitor resonates with the first resonant capacitors of different modules. However, due to the presence of the iron core magnetic circuit, the resonance effect of these two capacitors is relatively small, which is used to eliminate the leakage inductance generated by the first isolation coil and improve system efficiency.

[0018] This invention presents a novel combination method compared to traditional transformers. The isolation coil and power supply coil each perform their specific functions: the isolation coil handles power transmission between stages, while the power supply coil supplies power to the IGBT in a given stage. Traditional primary and secondary coils lack leakage inductance, do not incorporate resonant capacitors, and have a unidirectional power transmission. The transformer modules utilize magnetic coupling resonant wireless power transmission. Insulation increases with the number of module stages. This invention solves the problem of unstable power supply due to main circuit undervoltage in capacitor-dividend transformers while simultaneously improving the transformer's insulation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a single transformer module of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of adjacent transformer modules of the present invention.

[0022] Figure 3 This is a schematic diagram of the wireless power supply of the present invention.

[0023] In the diagram: 1. IGBT; 2. First isolation coil; 3. Second isolation coil; 4. Power supply coil; 5. First resonant capacitor; 6. Second resonant capacitor; 7. Iron core; 8. Drive circuit; 9. Rectifier diode; 10. Load. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0028] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0029] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0030] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0031] like Figure 1-3As shown, this invention provides a multi-stage wireless power supply coupling transformer, comprising: several stages of transformer modules connected in sequence. Each stage of the transformer module includes a connected IGBT1 and a transformer. The transformer includes a first isolation coil 2, a second isolation coil 3, a power supply coil 4, a first resonant capacitor 5, a second resonant capacitor 6, an iron core 7, and a drive circuit 8. The iron core 7 is a ring-shaped square iron core used to constrain the electromagnetic path of the coil. The first isolation coil 2 and the second isolation coil 3 for transmitting power at each stage are wound from top to bottom on the two longitudinal sides of the iron core 7, respectively. The power supply coil 4 for supplying power to the IGBT1 is wound on one transverse side of the iron core 7. The power supply coil 4 is connected to the drive circuit 8. The drive circuit 8 is connected to the gate (G) stage of the IGBT1 and controls the conduction and cutoff of the IGBT1. The first isolation coil 2 is connected to the second isolation coil 3 in the previous stage transformer module, and the second isolation coil 3 is connected to the first isolation coil 2 in the next stage transformer module, so as to realize the transmission of wireless power. A first resonant capacitor 5 is connected in parallel between the second isolation coil 3 in the previous stage transformer module and the first isolation coil 2 in the next stage transformer module. The power supply coil 4 is connected in parallel with a second resonant capacitor 6. The first resonant capacitor 5 is used to eliminate the leakage inductance generated by the first isolation coil 2 and the second isolation coil 3, and the second resonant capacitor 6 is used to eliminate the leakage inductance generated by the power supply coil 4. The emitter (E) stage of IGBT 1 is connected to the collector (C) stage of IGBT 1 in the next stage transformer module, and the collector (C) stage of IGBT 1 is connected to the emitter (E) stage of IGBT 1 in the previous stage transformer module. The turns ratio of the first isolation coil 2 to the second isolation coil 3 between stages varies with the stage number n. The first isolation coil 2 in the previous stage and the second isolation coil 3 in the next stage have the same number of turns. Within the same stage, the second isolation coil 3 and the power supply coil 4 have the same number of turns.

[0032] This invention relates to a wireless power supply method using multi-stage coupled transformers, particularly applicable to high-voltage motor control or DC power transmission using IGBTs in series. Unlike traditional multi-level transformers for IGBT power supply, this invention incorporates an iron core (7) to increase magnetic flux and a parallel resonant capacitor for the coupling coils to reduce leakage inductance, resulting in a more stable and reliable power supply. The multi-stage coupled transformer wireless power supply method is paired with IGBTs in series, with the transformer providing power to each stage of the IGBTs. A module is defined as a combination of a single IGBT and a single transformer. A module is essentially one stage of the multi-stage coupled transformer. This power supply method represents a novel combination compared to traditional transformers. The isolation coil and the power supply coil each have their specific functions: the isolation coil handles power transmission between stages, while the power supply coil supplies power to the IGBTs in a specific stage. Traditional primary and secondary coils lack leakage inductance and resonant capacitors, and the power transmission direction is unidirectional. The high-frequency alternating power supply for the entire system is connected from the lowest-level transformer terminal.

[0033] Figure 2 The connection details of adjacent transformer modules are described. The second isolation coil 3 in the intermediate-stage transformer module is connected to the first isolation coil 2 in the next-stage transformer module. The changing current is obtained from the second isolation coil 3 in the lowest-stage transformer module and the high-frequency alternating power supply. The first isolation coil 2 in the intermediate-stage transformer module is connected to the second isolation coil 3 in the previous-stage transformer module. The induced current generated by the first isolation coil 2 in the intermediate-stage transformer module flows to the next-stage transformer module through the second isolation coil 3 in the previous-stage transformer module, thus realizing wireless power transmission. A first resonant capacitor 5 is connected in parallel between the modules. This first resonant capacitor 5 resonates with the second resonant capacitor 6 of different modules, but due to the presence of the iron core magnetic circuit, the resonance effect of these two capacitors is relatively small. The selection of the first resonant capacitor 5 depends on the inductance of the closed coil. Since each module is in a resonant state during system operation, i.e., ω... i L i (Inductance of the i-th closed coil) = 1 / ω i C i (The i-th resonant capacitor) where ω i Let ω0 be the resonant frequency between the first closed coil and the adjacent closed coil. ω0 is the resonant frequency of the system. To achieve optimal coupling, ω0 must be equal to ω0. i .

[0034] The second isolation coil 3 in the intermediate stage transformer module forms a closed loop with the first isolation coil 2 in the next stage transformer module, and they have the same number of turns. This closed loop coil, plus the first resonant capacitor 5, magnetically couples with the closed loop formed by the first isolation coil 2 in the intermediate stage transformer module and the second isolation coil 3 in the previous stage transformer module, plus the first resonant capacitor 5. This achieves power transfer and electrical isolation between stages. The collector (C) of IGBT 1 in the intermediate stage transformer module is connected to the emitter (E) of IGBT 1 in the next stage transformer module, and the emitter (E) of IGBT 1 in the intermediate stage transformer module is connected to the collector (C) of IGBT 1 in the previous stage transformer module. The transformer provides power to the upper arm of the series-connected IGBTs. Because the IGBTs used are of the same specification, each module provides the same potential difference, thus enabling the potential to rise from zero to the highest voltage.

[0035] Figure 1 This is a detailed diagram of the intermediate stage transformer module. Figure 1The core 7 is wound longitudinally with M and N turns of the first isolation coil 2 and the second isolation coil 3. The values ​​of M and N depend on the voltage rating of IGBT1. Since IGBT1 requires the same power supply, the coil turns ratio is (n+1∶n) (N = total voltage, e.g., 10kV divided by the IGBT voltage rating of 1000V, N (total number of stages) = 10. n represents the number of stages). The high-frequency alternating power supply generates a changing current, which first flows through a capacitor for filtering, while the capacitor reduces the leakage inductance of the isolation coil. Then it flows through the second isolation coil 3 to generate a changing magnetic field. The magnetic flux of the changing magnetic field is confined in the square core 7. The first isolation coil 2 receives an induced current in the changing magnetic field. The changing current in the first isolation coil 2 flows to the next stage transformer module, serving as the current source for the next stage transformer module. The power supply coil 4 is wound on the right side of the core 7 laterally. The number of turns of the power supply coil 4 is the same as that of the second isolation coil 3. The isolation coil 3 has the same number of turns. The power supply coil 4 is connected in series with a rectifier diode 9 and in parallel with a second resonant capacitor 6. The second resonant capacitor 6 reduces leakage inductance, making the power supply more stable. The power supply coil 4 induces a changing current in the changing magnetic field. The rectifier diode 9 further stabilizes the induced current. The induced current then flows through the drive circuit 8, which is connected after the rectifier diode and the resonant capacitor, in series with the rectifier diode 9 and in parallel with the resonant capacitor. The drive circuit includes a drive power supply and a control module. The drive circuit 8 has two interfaces: the upper interface is connected to the gate (G) of IGBT 1, and the lower interface is connected to the emitter (E) of IGBT 1, thereby providing power and controlling the switching of IGBT 1. A high voltage is generated to supply the load.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage wireless power supply coupling transformer, characterized in that, include: A series of transformer modules are connected in sequence. Each transformer module includes an IGBT (1) and a transformer. The transformer includes a first isolation coil (2), a second isolation coil (3), a power supply coil (4), a first resonant capacitor (5), a second resonant capacitor (6), an iron core (7), and a drive circuit (8). The iron core (7) is a ring-shaped square iron core used to constrain the electromagnetic path of the coil. The first isolation coil (2) and the second isolation coil (3) for transmitting electrical energy at each level are wound from top to bottom on the two longitudinal sides of the iron core (7). The power supply coil (4) for supplying power to the IGBT (1) is wound on one transverse side of the iron core (7). The power supply coil (4) is connected to the drive circuit (8). The drive circuit (8) is connected to the IGBT (1) and controls the conduction and cutoff of the IGBT (1). The first isolation coil (2) is connected in parallel to the second isolation coil (3) in the previous stage transformer module, and the second isolation coil (3) is connected in parallel to the first isolation coil (2) in the next stage transformer module, so as to realize the transmission of wireless power; The second isolation coil (3) in the upper-level transformer module and the first isolation coil (2) in the lower-level transformer module are both connected in parallel with the first resonant capacitor (5). The power supply coil (4) is connected in parallel with the second resonant capacitor (6). The first resonant capacitor (5) is used to eliminate the leakage inductance generated by the first isolation coil (2) and the second isolation coil (3). The second resonant capacitor (6) is used to eliminate the leakage inductance generated by the power supply coil (4).

2. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: The E stage of the IGBT (1) is connected to the C stage of the IGBT (1) in the next stage transformer module, and the C stage of the IGBT (1) is connected to the E stage of the IGBT (1) in the previous stage transformer module.

3. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: The IGBTs (1) in each level of transformer module adopt the same specification.

4. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: The ratio of the number of turns of the first isolation coil (2) to the number of turns of the second isolation coil (3) between each level is (n+1∶n), where n is the level represented.

5. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: The number of turns of the first isolation coil (2) of the previous stage and the second isolation coil (3) of the next stage are the same.

6. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: In the same stage, the second isolation coil (3) has the same number of turns as the power supply coil (4).

7. The multi-stage wireless power supply coupling transformer according to claim 1, characterized in that: A rectifier diode (9) for rectification is connected in series between the power supply coil (4) and the drive circuit (8).

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