Magnetic integrated transformation device and charger

Abstract

The invention discloses a magnetic integrated transformation device and a charger, the magnetic integrated transformation device comprises a magnetic core and windings wound on the magnetic core, the windings comprise a first winding, a second winding and a third winding, the first winding is divided into a first winding group a and a first winding group b, the first winding group a and the first winding group b are distributed at two sides of the second winding, and the third winding is distributed at two sides of the second winding. The second winding and the third winding are mutually laminated; magnetic leakage inductors are led out from the head and tail ends of the first winding; according to the invention, the integration of the OBC for charging the high-voltage battery and the LDC for charging the low-voltage battery is realized, the power inductance of the OBC is integrated through the leakage inductance of the transformer, the volume and weight of the magnetic element of the charger are effectively reduced, the charging and inversion functions of the charger are not influenced by the magnetic integrated transformation device provided by the invention, and the cost is reduced. The high-voltage battery and the low-voltage battery can be charged at the same time, and the power density of the charger is improved; the method provided by the invention has universality for OBC topologies with power inductors, such as a dual-active bridge converter and a resonant converter.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly to a magnetic integrated voltage conversion device and a charger. Background Art

[0002] On-board chargers (OBCs) are an important part of the battery charging system and usually have a two-stage structure: a power factor correction (PFC) stage cascaded with a DC-DC stage, which is used to charge a high-voltage battery (HVB). For safety reasons, the DC-DC is implemented by an isolated topology, such as a resonant converter or a dual-active bridge converter. In addition, there is also a low-voltage battery (LVB) in electric vehicles, which is used to supply power to the low-voltage devices of the vehicle. Therefore, an additional isolated DC-DC converter is required. Since the installation space of the on-board charger in an electric vehicle is limited, and magnetic components such as resonant inductors and transformers account for a relatively large proportion of the volume and weight of the OBC, it severely limits the power density of the OBC and increases the cost of the OBC.

[0003] Magnetic integration is an effective method to reduce the overall volume of magnetic components. In recent years, in order to improve the power density of the OBC, there have been studies on the integration of the OBC and the low-voltage DC-DC in the literature. Considering magnetic integration and the battery voltage range, the three-port converter topology is a very attractive option for the OBC. Isolation between the three ports can be achieved by a dual transformer or a three-winding transformer.

[0004] Magnetic components are a complex combination of high-frequency magnetic fields, electric fields, and current fields. As the OBC develops towards high frequency, high power density, bidirectional power conversion, low cost, small size, light weight, multi-function, etc., the magnetic integration design of the OBC becomes more complex. Unreasonable parameter models, winding designs, and magnetic core selections will all reduce the performance of the OBC. In severe cases, problems such as magnetic core saturation and cracking will occur, resulting in device failure and reducing the reliability of the OBC. High frequency also poses severe challenges to the magnetic integration structure, such as heat dissipation and EMI. Therefore, under the multi-functional battery charging requirements of the OBC, such as grid-to-vehicle (G2V), vehicle-to-grid (V2G), vehicle-to-load (V2L), high-voltage battery-to-low-voltage battery (H2L), etc., the existing magnetic integration devices cannot well meet the requirements of high efficiency, small volume, and low cost. Summary of the Invention

[0005] In order to solve the above-mentioned defects existing in the prior art, the present invention proposes a magnetic integrated voltage conversion device and a charger.

[0006] The technical solution adopted by the present invention is to design a magnetic integrated transformer device, which includes a magnetic core and windings wound around the magnetic core. The windings include a first winding, a second winding, and a third winding. The first winding includes a first winding group a and a first winding group b. The first winding group a and the first winding group b are distributed on both sides of the second winding. The second winding and the third winding are stacked on top of each other. The head and tail ends of the first winding lead out leakage inductance.

[0007] Optionally, the first winding is attached to the magnetic core, the second winding is attached to the magnetic core, the third winding is wound outside the second winding, or the third winding is attached to the magnetic core and the second winding is wound outside the third winding.

[0008] Optionally, a magnetic ring is provided between the first winding group a and the second winding, and a magnetic ring is provided between the first winding group b and the second winding. The magnetic ring is sleeved on the outer periphery of the magnetic core around which the first winding and the second winding are wound.

[0009] Optionally, the magnetic core includes a first winding section for winding the first winding and a second winding section for winding the second winding and the third winding. The cross-section of the second winding section is smaller than the cross-section of the first winding section.

[0010] Optionally, the first winding and the second winding are wound with round wires or stranded wires, and the third winding is wound with foil or Litz wire.

[0011] Optionally, the magnetic core is formed by enclosing a first magnet and a second magnet. The first magnet and the second magnet adopt the same E-shaped structure. The first winding section and the second winding section are sequentially arranged on the central column of the first magnet or the second magnet from its root outwards.

[0012] Optionally, an air gap for adjusting the leakage inductance value of the leakage inductance is provided between the two contact surfaces where the first magnet and the second magnet are in contact with each other; or the two contact surfaces are in direct contact.

[0013] Optionally, by adjusting the distance between the first winding, the second winding, and the third winding, and the dimensions of the wires of each winding, the total leakage energy W of the transformer is adjusted leakage , so as to control and adjust the leakage inductance L m of the leakage inductance L s value.

[0014] The control and adjustment of the leakage inductance L m of the leakage inductance L sThe size specifically includes: calculating the total energy W based on the energy stored between the layers of the first winding, the second winding, and the third winding, the energy stored between the second winding and the third winding, and the energy stored in the litz wires of the first winding, the second winding, and the third winding all ; calculating the energy W stored in the strands of the litz wire based on the number of layers of the first winding, the number of strands of the litz wire, the leakage magnetic length of a single-turn wire, and the effective current value, and the number of layers, turns, strands of the litz wire, and the effective current value of the second winding con ; subtracting the energy W stored in the strands of the litz wire from the total energy W all to obtain the total magnetic field leakage energy W con ; calculating the leakage inductance L based on the effective current value of the first winding and the total magnetic field leakage energy W leakage ; leakage s .

[0015] The present invention also discloses a charger, which includes a primary conversion circuit, a transformer, a bidirectional high-voltage DC conversion circuit, and a low-voltage DC conversion circuit. The transformer adopts the above-mentioned magnetic integration voltage conversion device, and the first winding is connected to the primary conversion circuit, the second winding is connected to the bidirectional high-voltage DC conversion circuit, and the third winding is connected to the low-voltage DC conversion circuit.

[0016] The beneficial effects of the technical solution provided by the present invention are as follows:

[0017] The present invention realizes the integration of the OBC for charging high-voltage batteries and the LDC for charging low-voltage batteries, and integrates the power inductor of the OBC through the leakage inductance of the transformer, effectively reducing the volume and weight of the magnetic components of the charger. The magnetic integration voltage conversion device proposed by the present invention does not affect the charging and inversion functions of the charger, and can realize the simultaneous charging of high-voltage batteries and low-voltage batteries, improving the power density of the charger; the present invention is applicable to OBC topologies with power inductors such as dual-active-bridge converters and resonant converters. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be described in detail below in conjunction with embodiments and drawings, where:

[0019] Figure 1 is an exploded three-dimensional schematic diagram of the magnetic integration voltage conversion device;

[0020] Figure 2 is an exploded three-dimensional schematic diagram with the third winding using a foil;

[0021] Figure 3a is a three-dimensional schematic diagram of the magnetic core without windings;

[0022] Figure 3b ​It is a schematic diagram of a magnetic integrated transformer after winding the second winding;

[0023] Figure 3c It is a schematic diagram of a magnetic integrated transformer after winding the second and first windings;

[0024] Figure 3d It is a schematic diagram of a magnetic integrated transformer after winding the second, first and third windings;

[0025] Figure 4a It is a three-dimensional schematic diagram of a C-shaped magnetic core without winding;

[0026] Figure 4b It is a three-dimensional explosion decomposition schematic diagram using a C-shaped magnetic core;

[0027] Figure 5 It is a circuit schematic diagram of a magnetic integrated transformer;

[0028] Figure 6 It is a schematic diagram of the magnetic circuit parameters of a magnetic integrated transformer;

[0029] Figure 7 It is an application example of a magnetic integrated transformer in a charger;

[0030] Figure 8 It is a schematic diagram of a magnetic integrated transformer using a C-shaped magnetic core and a magnetic ring;

[0031] Figure 9 It is a three-dimensional explosion decomposition schematic diagram of a magnetic integrated transformer using a C-shaped magnetic core and a magnetic ring;

[0032] Figure 10 It is a finite element simulation of an E-shaped magnetic integrated transformer: magnetic induction intensity simulation diagram;

[0033] Figure 11 It is a finite element simulation of an E-shaped magnetic integrated transformer: magnetic field intensity simulation diagram;

[0034] Figure 12 It is a finite element simulation of a C-shaped magnetic integrated transformer: magnetic induction intensity simulation diagram;

[0035] Figure 13 It is a finite element simulation of a C-shaped magnetic integrated transformer: magnetic field intensity simulation diagram;

[0036] Description of the reference numerals in the figure: The first winding section (1), the second winding section (2), the air gap (4), the first winding (W1), the second winding (W2), the third winding (W3), the first winding group a (W1a), the first winding group b (W1b), the magnetic ring (5), the first magnet (10), the second magnet (20). Detailed implementation

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Referring to Figure 1 the exploded three-dimensional schematic diagram of the magnetic integrated transformer device shown, the magnetic integrated transformer device disclosed by the present invention includes a magnetic core and windings wound around the magnetic core. The windings include a first winding W1, a second winding W2, and a third winding W3. The first winding W1 includes a first winding a group W1a and a first winding b group W1b. The first winding a group W1a and the first winding b group W1b are distributed on both sides of the second winding W2. The second winding W2 and the third winding W3 are stacked on top of each other. The head and tail ends of the first winding W1 lead out a leakage inductance L m . It should be noted that in a preferred embodiment, the first winding W1 is evenly divided into a first winding a group W1a and a first winding b group W1b, that is, the number of turns and other parameters of the first winding a group W1a and the first winding b group W1b are the same.

[0039] The magnetic integrated transformer device disclosed by the present invention is applicable to an on-vehicle charger. It is a three-port transformer that includes a high-frequency isolation transformer for OBC, a high-frequency isolation transformer for low-voltage DC-DC, and a power inductor for OBC. This device is universal for OBC topologies with power inductors such as dual-active-bridge converters and resonant converters. Referring to Figure 5 the circuit schematic diagram shown, the leakage inductance L m is connected in parallel with the first winding W1. The present invention integrates the OBC for high-voltage battery charging and the DC-DC for low-voltage battery charging through the magnetic integrated transformer device, and uses the transformer leakage inductance to integrate the power inductor in the OBC topology.

[0040] Refer to Figure 6, the third winding W3 and the second winding W2 of the magnetic integrated transformer device are wound by lamination, with a high degree of coupling. The first winding W1 is wound by its own lamination, with a lower degree of coupling with the second winding W2. Moreover, the first winding W1 is evenly divided into two parts, symmetrically placed on both sides of the second winding W2 and the third winding W3, and kept at a certain distance from the second winding W2. Therefore, part of the magnetic lines of force generated by the second winding W2 and the first winding W1 form a closed loop through the air between the windings, forming leakage magnetic flux. The lamination winding of the second winding W2 and the third winding W3 results in a high degree of coupling between the two, and the formed first leakage inductance is small, which can reduce the power transmission loss between the second winding W2 and the third winding W3 and improve the efficiency of the OBC charging the low-voltage battery. While the coupling degree between the first winding and the second winding is low, and the formed second leakage inductance is large. The second leakage inductance can be used as the power inductor of the power converter, such as the resonant inductor, which can reduce the volume of the OBC magnetic components. By adopting the above transformer structure, the coupling degree of each winding of the transformer can be improved, effectively solving the problem of the large volume of the magnetic components in the OBC, realizing the precise control of the leakage inductance of the transformer, and enabling the simultaneous charging of the HVB and the LVB without additional components, and meeting the multi-functional charging requirements of the OBC.

[0041] The first winding W1 is attached to the magnetic core, the second winding W2 is attached to the magnetic core, and the third winding W3 is wound outside the second winding W2. It should be noted that in this embodiment, the second winding W2 and the third winding W3 are wound on the magnetic core in a layered and overlapping manner. "The third winding W3 is wound outside the second winding W2" means that the second winding W2 is wound on the magnetic core and the third winding W3 is wound on the second winding W2. In other embodiments, the third winding W3 is attached to the magnetic core and the second winding W2 is wound outside the third winding W3.

[0042] To increase the ways of adjusting the leakage inductance, in Figure 8 and Figure 9 Some of the illustrated embodiments, a magnetic ring 5 sleeved on the outer periphery of the magnetic core is added. Figure 8 is a schematic diagram of a magnetic integrated transformer device using a C-shaped magnetic core and a magnetic ring, Figure 9 is an exploded three-dimensional schematic diagram of a magnetic integrated transformer device using a C-shaped magnetic core and a magnetic ring. A magnetic ring 5 is provided between the first winding a group W1a and the second winding W2, and a magnetic ring 5 is provided between the first winding b group W1b and the second winding W2. The magnetic ring 5 is sleeved on the outer periphery of the magnetic core around which the first winding W1 and the second winding W2 are wound. The magnetic ring 5 is made of a magnetic conductive material and is in the shape of a long rectangle as a whole, and its outer peripheral dimensions do not exceed the outer peripheral dimensions after the second winding W2 and the third winding W3 overlap. The magnetic ring 5 is located in the leakage field area of the overlapping windings of the first winding W1 and the second winding W2 and the third winding W3. In this way, the magnetic ring 5 can constrain the leakage magnetic field and adjust the value of the leakage inductance, which is equivalent to adding an auxiliary way to adjust the leakage inductance.

[0043] Figure 3 shows the process of preparing a magnetically integrated transformer device, Figure 3a which is a three-dimensional schematic diagram of the magnetic core without windings, Figure 3b which is a schematic diagram of the magnetically integrated transformer device after winding the second winding, Figure 3c which is a schematic diagram of the magnetically integrated transformer device after winding the second and first windings, Figure 3d which is a schematic diagram of the magnetically integrated transformer device after winding the second, first, and third windings. First, the second winding W2 is wound through the magnetic core window at the central position of the magnetic column, as Figure 3b shown; then, after evenly dividing the number of turns of the first winding W1, it is wound through the magnetic core window and symmetrically wound on both sides of the second winding W2, as Figure 3c shown; finally, the third winding W3 is wound through the magnetic core window at the central position of the magnetic column, and the third winding and the second winding are wound in a stacked manner to ensure tight coupling between the third winding and the second winding, as Figure 3d shown.

[0044] In a preferred embodiment, since the second winding W2 and the third winding W3 are wound in an overlapping manner, in order to avoid bulges at the winding positions of the second winding W2 and the third winding W3, the cross-sectional areas of the iron cores at the winding positions of the first winding W1 and the second winding W2 are set differently. Combining Figure 1 , Figure 2 and Figure 3a , the magnetic core includes a first winding section 1 for winding the first winding W1 and a second winding section 2 for winding the second winding W2 and the third winding W3, and the cross-section of the second winding section 2 is smaller than that of the first winding section 1. Figure 3d shows the effect after winding the first, second, and third windings. There are no bulges at the winding positions of the second winding W2 and the third winding W3, and they are basically flush with the winding position of the first winding W1. With such a structure, the volume of the transformer device can be reduced and the power density of the transformer device can be increased.

[0045] Referring to Figure 2 an embodiment disclosed, the first winding W1 and the second winding W2 are wound with round wires or stranded wires, and the third winding W3 is wound with foil or Litz wire and can be in a flat shape. The windings of the first winding W1 and the second winding W2 are fixed by a bobbin. The third winding and the second winding are wound in a stacked manner and the stacking order can be exchanged. The Litz wire is a wire composed of multiple independently insulated wires twisted or braided together. Applying it in a transformer can reduce the skin effect and mutual inductance loss. The third winding W3 made of Litz wire is stacked on the second winding W2 and can be 1 turn or multiple turns.

[0046] Optionally, the number of turns of the first winding W1 and the second winding W2 can be equal or unequal.

[0047] See Figure 1 and Figure 2 In some embodiments, the magnetic core is surrounded by a first magnet 10 and a second magnet 20. The first magnet 10 and the second magnet 20 adopt the same E-shaped structure. The first winding section 1 and the second winding section 2 are sequentially arranged on the middle column of the first magnet 10 or the second magnet 20 from its root outwards.

[0048] See Figure 4a The three-dimensional schematic diagram of the C-shaped magnetic core without winding shown Figure 4b The exploded three-dimensional schematic diagram using a C-shaped magnetic core shown. The magnetic core adopts a C-shaped magnetic core, and a first winding section 1 for winding the first winding W1 and a second winding section 2 for winding the second winding W2 and the third winding W3 are also provided at the winding position.

[0049] Optionally, the magnetic core can adopt a conventional E-shaped magnetic core or an E-shaped magnet with a groove, such as magnetic cores like EE type, EER type, EI type, EM type, EFD type, EK type, ER type, etc. Optionally, the shape of the magnetic core can also be a special-shaped magnetic core with a middle column.

[0050] An air gap 4 for adjusting the leakage inductance L m of the leakage inductance L s is provided between the two contact surfaces where the first magnet 10 and the second magnet 20 are in contact with each other; or the two contact surfaces are in direct contact. In Figure 3a the embodiment shown, an air gap 4 is provided on the middle columns of the two E-shaped magnetic cores.

[0051] Optionally, the middle columns of the first magnet 10 and the second magnet 20 can be integrated with the magnetic core or separated. After the middle columns are separated from the magnetic core, the air gap of the magnetic core can be the gap between the middle columns and the magnetic core. Optionally, no air gap can be opened between the first magnet 10 and the second magnet 20, and the size of the leakage inductance can be controlled by adjusting the coupling degree between the first winding 10 and the second winding 20. Optionally, one or more air gaps can be provided in the magnetic core, which can reduce the magnetic permeability of the magnetic core and control the inductance of the magnetic integrated transformer device.

[0052] In a preferred embodiment, by adjusting the distances between the first winding W1, the second winding W2 and the third winding W3, and the dimensions of the wires of each winding, the total leakage energy W leakage of the transformer is adjusted to control and adjust the leakage inductance L m of the leakage inductance L s size.

[0053] The control and adjustment of the leakage inductance L m of the leakage inductance L s size specifically includes:

[0054] Calculate the total magnetic field leakage energy W according to Formula 1 leakage ,

[0055]

[0056] where m 0 is the magnetic permeability of air, H is the magnetic field strength, L s is the leakage inductance, I rms-1 is the effective value of the current in the first winding; in a preferred embodiment, the winding is wound with Litz wire, and the following formula is calculated according to Litz wire.

[0057] The total magnetic field leakage energy W leakage includes three parts: the energy stored between winding layers, the energy stored between windings, and the energy stored in the Litz wire of the winding (the energy stored in the winding wire). It should be noted that the energy stored between winding layers, the energy stored between windings, and the energy stored in the Litz wire of the winding. The stored energy mentioned here refers to the stored leakage energy. Among them, the energy stored between winding layers is calculated according to Formula 2

[0058]

[0059] where the subscript A is a variable, and A = 1, 2, 3 represent the first winding W1, the second winding W2, and the third winding W3 respectively, W iso-A is the energy stored between the layers of winding A, μ 0 is the magnetic permeability of air, l iso-A is the leakage magnetic length of winding A, d iso-A is the insulation distance between the layers of winding A, h w-A is the height of winding A, m A is the number of layers of winding A, N A is the number of turns of winding A, I rms-A is the effective value of the current in winding A, and the total energy stored between the layers of the winding is the sum of W iso-1 , W iso-2 and W iso-3 ;

[0060] Let the voltage of the transformer winding be V A (A = 1, 2, 3), the voltage frequency is f s , then the number of turns of the winding is calculated by Formula 3

[0061]

[0062] where N A is the number of turns of winding A, which is determined by the type of magnetic core material, A e-A is the cross-sectional area of the magnetic core around which the winding is wound, B max is the maximum magnetic induction intensity,

[0063] The energy stored in the stacked second winding W2 and third winding W3 is calculated by the following formula:

[0064]

[0065] where W iso is the energy stored between the second winding W2 and the third winding W3, μ 0 is the magnetic permeability of air, l iso is the leakage magnetic length between the second winding W2 and the third winding W3, d iso is the isolation distance between the second winding and the third winding, h w2 is the width of the second winding, the second winding W2 and the third winding W3 have the same width, m 2 is the number of layers of the second winding, N 2 is the number of turns of the second winding W2, I rms-2 is the effective value of the current of the second winding W2;

[0066] The energy stored in the winding Litz wire is calculated according to Formula 5.

[0067]

[0068] where W win-A is the energy stored in the winding Litz wire, m A is the number of layers of winding A, where A = 1, 2, 3 represent the first winding W1, the second winding W2, and the third winding W3 respectively, l A is the leakage magnetic length of winding A, μ 0 is the magnetic permeability of air, h w is the width of the first winding, N A is the number of turns of winding A, I rms-A is the effective value of the current of winding A, σ' is the corrected conductivity of the wire of the winding, f is the operating frequency of the switching device connected to the magnetic integrated transformer device. It should be noted that the switching device is a power semiconductor device, d wA is the thickness of winding A (A = 1, 2, 3), δ is the skin depth, △, F 1 and F 2 are alternative expressions for simplified representation;

[0069] The equivalent expression of the winding thickness is calculated according to Formula 6.

[0070]

[0071] where d eq is the equivalent expression of the winding thickness, replacing the equivalent diameter of the circular stranded wire with a square stranded wire, d wA is the thickness of a single turn of winding A (A = 1, 2, 3), N sv represents the number of Litz layers in the vertical direction in the winding, hw is the window height of the magnetic core, N s represents the total number of strands of the litz wire, d w-A is the thickness of winding A (A = 1, 2, 3), η is the porosity factor, σ' is the corrected conductivity of the wire of the winding, and σ is the conductivity of the wire of the winding;

[0072] The total energy W all is calculated according to Equation 7,

[0073] W all = W iso-1 + W iso-2 + W iso-3 + W iso + W win-1 + W win-2 + W win-3 Equation 7

[0074] where, W all is the total energy stored in the first winding W1, the second winding W2, and the third winding W3, W iso-1 is the energy stored between the layers of the first winding, W iso-2 is the energy stored between the layers of the second winding, W iso-3 is the energy stored between the layers of the third winding, W iso is the energy stored between the second winding and the third winding, W win-1 is the energy stored in the litz wire of the first winding, W win-2 is the energy stored in the litz wire of the second winding, W win-3 is the energy stored in the litz wire of the third winding;

[0075] The leakage energy is calculated according to Equation 8,

[0076] W leakage = W all - W con Equation 8

[0077] where, W leakage is the total magnetic field leakage energy, W all is the total energy stored in the first winding W1, the second winding W2, and the third winding W3, W con is the energy stored in the strands of the litz wire of the winding;

[0078] The energy stored in the winding wire is calculated according to Equation 9,

[0079]

[0080] where, W con is the energy stored in the strands of the litz wire of the winding, m 1 is the number of layers of the first winding, N 2is the number of turns of the second winding, n 2 is the number of strands of Litz wire in the second winding, μ 0 is the magnetic permeability of air, l m is the leakage magnetic length of a single turn of the first winding. It should be noted that the wire diameters of the first winding W1 and the second winding W2 are the same, so the lm here is uniformly the leakage magnetic length of a single turn of the Litz wire winding, I rms-1 is the effective value of the current in the first winding, n 1 is the number of strands of Litz wire in the first winding, m 2 is the number of layers of the second winding, I rms-2 is the effective value of the current in the second winding;

[0081] Formula 1 can be transformed to obtain Formula 10,

[0082]

[0083] where, L s is the leakage inductance, I rms-1 is the effective value of the current in the first winding, W leakage is the total energy of magnetic field leakage, W all is the total energy stored in the first winding W1, the second winding W2 and the third winding W3, W con is the energy stored in the strands of the Litz wire of the winding.

[0084] The present invention also discloses a charger, which includes a primary conversion circuit, a transformer, a bidirectional high-voltage DC conversion circuit and a low-voltage DC conversion circuit. The transformer adopts the above-mentioned magnetic integrated voltage conversion device, and the first winding W1 (which can also be said to be the primary winding of the OBC transformer) is connected to the primary conversion circuit, the second winding W2 (which can also be said to be the secondary winding of the OBC transformer) is connected to the bidirectional high-voltage DC conversion circuit, and the third winding W3 (which can also be said to be the transformer winding of the LDC) is connected to the low-voltage DC conversion circuit.

[0085] Refer to Figure 7 the application example of the magnetic integrated voltage conversion device 16 shown in the charger. The above-mentioned primary conversion circuit includes an AC / DC converter 14 and an inverter bridge 15. The above-mentioned bidirectional high-voltage DC conversion circuit includes a first rectifier bridge 17. The above-mentioned low-voltage DC conversion circuit includes a second rectifier network 18. The AC / DC converter 14 is composed of an inductor Lg and switching tubes S 1 -S 4 and is connected to the input port A and the bus capacitor C bus , the inverter bridge 15 is composed of switching tubes Q 1 -Q 4 and is connected to the bus capacitor C bus , series capacitor C bFor the first winding W1 of the magnetic integration transformer device, the first rectifier bridge 17 is composed of switching tubes Q 5 -Q 8 The first rectifier bridge 17 is connected in series with capacitor C b , the second winding W2 of the magnetic integration transformer device 16 and C HV , L HV and C o to form a first filter network, and is connected to the output port B. The second rectifier network 18 is composed of switching tubes Q 9 -Q 12 The second rectifier network is connected to the third winding W3 of the magnetic integration transformer device and L o and C LV to form a second filter network, and is connected to the output port C.

[0086] The port A is connected to the power grid, the port B is connected to the high-voltage power battery, and the port C is connected to the low-voltage battery. By using the magnetic integration transformer device, charging modes such as G2V, V2G, and V2L of the charger can be realized, and charging from the high-voltage battery to the low-voltage battery and charging the high-voltage battery and the low-voltage battery by the power grid simultaneously can also be realized.

[0087] Figure 10 Fig. shows the magnetic induction intensity simulation diagram of the finite element simulation of the E-type magnetic integration transformer, Figure 11 Fig. shows the magnetic field intensity simulation diagram of the finite element simulation of the E-type magnetic integration transformer, Figure 12 Fig. shows the magnetic induction intensity simulation diagram of the finite element simulation of the C-type magnetic integration transformer, Figure 13 Fig. shows the magnetic field intensity simulation diagram of the finite element simulation of the C-type magnetic integration transformer. It can be seen from the magnetic induction intensity that there is leakage flux between the first winding W1 and the second winding W2, thus forming transformer leakage inductance. In the leakage magnetic region, the magnetic field intensity is relatively large. The magnetic induction intensity of the magnetic core is lower than the saturation magnetic induction intensity of the magnetic core, and the transformer can work normally. The simulation results show that through the transformer structure proposed by the present invention and by using the different types of magnetic cores described above, leakage inductance integration can be realized, and at the same time, the integration of OBC and LDC is realized, improving the power density of the charger.

[0088] The above embodiments are only for illustrative purposes and do not serve as limitations. Any equivalent modifications or changes made without departing from the spirit and scope of this application shall be included in the scope of the claims of this application.

Claims

1. A magnetic integrated transformer device, comprising a magnetic core and a winding wound on the magnetic core, characterized in that: The winding comprises a first winding (W1), a second winding (W2) and a third winding (W3), the first winding (W1) comprises a first winding group a (W1a) and a first winding group b (W1b), the first winding group a (W1a) and the first winding group b (W1b) are distributed on both sides of the second winding (W2), the second winding (W2) and the third winding (W3) are stacked on each other, and leakage magnetic inductance (L) is drawn out from both ends of the first winding (W1) m ).

2. The magnetic integrated transformer device according to claim 1, characterized in that: The first winding (W1) is attached to the magnetic core, the second winding (W2) is attached to the magnetic core, and the third winding (W3) is wound on the outside of the second winding (W2), or the third winding (W3) is attached to the magnetic core, and the second winding (W2) is wound on the outside of the third winding (W3).

3. The magnetic integrated transformer device according to claim 1, characterized in that: A magnetic ring (5) is provided between the first winding group a (W1a) and the second winding (W2), and a magnetic ring (5) is provided between the first winding group b (W1b) and the second winding (W2); the magnetic ring (5) is sleeved on the outer circumference of the magnetic core wound around the first winding (W1) and the second winding (W2).

4. The magnetic integrated transformer device according to claim 1, characterized in that: The magnetic core comprises a first winding section (1) for winding a first winding (W1), and a second winding section (2) for winding the second winding (W2) and the third winding (W3), wherein the cross section of the second winding section (2) is smaller than the cross section of the first winding section (1).

5. The magnetic integrated transformer device according to claim 1, characterized in that: The first winding (W1) and the second winding (W2) are wound with round wires or stranded wires, and the third winding (W3) is wound with foil or Litz wire.

6. The magnetic integrated transformer device according to claim 4, characterized in that: The magnetic core is formed by surrounding a first magnet (10) and a second magnet (20); the first magnet (10) and the second magnet (20) have the same E-shaped structure; the first winding section (1) and the second winding section (2) are sequentially arranged on the center column of the first magnet (10) or the second magnet (20) from its root outwards.

7. The magnetic integrated transformer device according to claim 6, characterized in that: A leakage inductance adjustment device (L) is provided between two contact surfaces of the first magnet (10) and the second magnet (20) that contact each other. m ) leakage inductance (L s ) size of air gap (4); or direct contact between the two contact surfaces.

8. The magnetic integrated transformer device according to claim 1, characterized in that: By adjusting the distance between the first winding (W1), the second winding (W2) and the third winding (W3), as well as the size of the wires of each winding, the total leakage energy W of the transformer can be adjusted. leakage , to control and adjust the leakage inductance (L m ) leakage inductance (L s )size.

9. The magnetic integrated transformer device according to claim 8, characterized in that: The control adjusts the leakage inductance (L m ) leakage inductance (L s ) Sizes include: The total energy W is calculated based on the energy stored between the first winding (W1), the second winding (W2) and the third winding (W3) layers, the energy stored between the second winding (W2) and the third winding (W3), and the energy stored in the Litz wires of the first winding (W1), the second winding (W2) and the third winding (W3). all ; The energy W stored in the strands of the Litz wire is calculated based on the number of layers of the first winding (W1), the number of strands of the Litz wire, the leakage magnetic length of a single turn of the conductor and the effective value of the current, and the number of layers, the number of turns, the number of strands of the Litz wire and the effective value of the current of the second winding (W2). con ; The total energy W all Subtract the energy stored in the strands of Litz wire, W con The total magnetic field leakage energy W is obtained leakage ; According to the effective value of the current of the first winding and the total magnetic field leakage energy W leakage Calculate the leakage inductance L s .

10. A charger, comprising a primary side conversion circuit, a transformer, a bidirectional high voltage DC conversion circuit and a low voltage DC conversion circuit, characterized in that: The transformer adopts the magnetic integrated transformer device according to any one of claims 1 to 9, and the first winding (W1) is connected to the primary conversion circuit, the second winding (W2) is connected to the bidirectional high-voltage DC conversion circuit, and the third winding (W3) is connected to the low-voltage DC conversion circuit.

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