Transformer and power conversion device having same

Abstract

A transformer and a power conversion device having same, according to an aspect of the present disclosure, include a first core and a multi-layer circuit board which has conductive patterns through which currents for creating a magnetic flux within the first core flow, the first core comprising: a base; a first leg and a second leg protruding from the base; and a third leg disposed between the first leg and the second leg and having a cross-sectional area smaller than the combined cross-sectional areas of the first leg and the second leg.

Description

Transformer and power conversion device having the same

[0001] The present disclosure relates to a transformer and a power conversion device having the same, and more particularly, to a transformer that can be made lightweight and miniaturized, and a power conversion device having the same.

[0002] Vehicles require a power supply to operate various devices. To achieve this, a power converter is needed to convert the DC power level from the battery and supply the converted power to other devices.

[0003] Meanwhile, electric vehicles powered by electricity, or hybrid vehicles combining internal combustion engines with internal combustion engines, generate their power using motors and batteries. Furthermore, power conversion devices are also required to drive the motors.

[0004] A power conversion device may include a converter that converts the level of a DC power source such as a battery. Examples of converters include an LLC resonant converter and a PWM converter. These LLC resonant converters and PWM converters include a transformer and the like.

[0005] Korean Patent Publication No. 10-1105536 (hereinafter referred to as "prior document") discloses a converter utilizing a planar transformer to increase power conversion efficiency. The power conversion device of the prior document comprises two transformers, two core sets (121-1 & 122-1) (121-2 & 122-2), and a PCB pattern winding (110).

[0006] Figures 11 and 12 illustrate top and side views of two planar type transformers with PCB windings according to the prior art. Referring to Figures 11 and 12, a U-shaped upper core and an I-shaped lower core are exemplified, and two core sets (core sets 1 and 2) are provided. In addition, magnetic flux is formed in the same direction in the two cores (core 1-2, core 2-1). This structure may take up a lot of space and lead to increased weight and manufacturing costs.

[0007]

[0008] The purpose of the present disclosure is to provide a transformer capable of reducing volume and weight, and a power conversion device having the same.

[0009] The purpose of the present disclosure is to provide a transformer capable of reducing core loss and a power conversion device having the same.

[0010] The purposes of the present disclosure are not limited to those mentioned above, and other purposes not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] A transformer and a power conversion device having the same according to one aspect of the present disclosure include: a first core; and a multi-circuit board having a conductive pattern formed thereon, through which a current generating a magnetic flux flows in the first core; wherein the first core includes: a base; first and second legs protruding from the base; and a third leg disposed between the first and second legs; wherein a cross-sectional area of ​​the third leg is formed to be smaller than the sum of the cross-sectional areas of the first leg and the second leg.

[0012] A transformer and a power conversion device including the same according to one aspect of the present disclosure include: a first core including a base, first and second legs protruding from the base, and a third leg disposed between the first and second legs; and a multi-circuit board having a plurality of conductive patterns formed thereon through which a current that generates magnetic flux flows in the first core; wherein the plurality of conductive patterns are formed such that the magnetic flux is canceled out in the third leg. In this case, the cross-sectional area of ​​the third leg may be smaller than the sum of the cross-sectional areas of the first leg and the second leg.

[0013] The multi-circuit board may include a first layer including a first current pattern flowing in a first direction on one side of the third leg and a second layer including a second current pattern flowing in the first direction on the other side of the third leg.

[0014] The first current pattern may be such that the current flows into the outer portion of the first leg, surrounds the first leg and the third leg, and passes between the third leg and the second leg.

[0015] The second current pattern may be such that the current flows into the outer portion of the second leg, surrounds the second leg and the third leg, and passes between the third leg and the first leg.

[0016] The second current pattern may be connected to the first current pattern at the outer edge of the second leg.

[0017] In the third leg, the magnetic flux generated by the current flowing in the first current pattern and the magnetic flux generated by the current flowing in the second current pattern can be canceled out.

[0018] The transformer and power conversion device may further include a second core facing the first core.

[0019] A transformer and a power conversion device having the same according to one aspect of the present disclosure include a third core and a fourth core arranged side by side; and a multi-circuit board having a plurality of conductive patterns formed thereon, through which a current that generates magnetic flux flows in the third core and the fourth core; wherein the third core and the fourth core each include two legs having different cross-sectional areas.

[0020] Among the four legs of the third core and the fourth core, the cross-sectional area of ​​the two legs located in the center may be smaller than the cross-sectional areas of the remaining two legs.

[0021] The above plurality of conductive patterns can be formed so that the magnetic flux is canceled out in the two legs located in the center.

[0022] According to at least one of the embodiments of the present disclosure, the manufacturing cost can be lowered and the efficiency can be improved by reducing the volume and weight of the transformer.

[0023] According to at least one of the embodiments of the present disclosure, the energy efficiency of a vehicle can be improved by reducing core loss of a transformer.

[0024] Meanwhile, various other effects will be disclosed directly or implicitly in the detailed description according to the embodiments of the present disclosure to be described later.

[0025] FIG. 1 is a schematic drawing showing a body of a vehicle according to one embodiment of the present disclosure.

[0026] FIG. 2 is an example of a vehicle drive system according to one embodiment of the present disclosure.

[0027] Fig. 3 illustrates an example of the internal convexity of the motor drive device of Fig. 2.

[0028] FIGS. 4 to 7 are drawings for reference in the description of the main configuration of a transformer according to one embodiment of the present disclosure.

[0029] FIGS. 8 to 10 are drawings for reference in the description of the main configuration of a transformer according to an embodiment of the present disclosure.

[0030] Figures 11 and 12 are drawings for reference in the description of a transformer according to the prior art.

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. However, the present disclosure is not limited to these embodiments and can be modified in various forms.

[0032] Meanwhile, the suffixes "module" and "part" used in the following description are given solely for the convenience of writing this specification, and do not impart any particularly significant meaning or role to them. Therefore, the terms "module" and "part" may be used interchangeably.

[0033] In addition, in this specification, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0034] Additionally, while terms such as "first" and "second" may be used in this specification to describe various elements, these elements are not limited by these terms. These terms are used only to distinguish one element from another.

[0035] FIG. 1 is a schematic drawing showing a body of a vehicle according to one embodiment of the present disclosure.

[0036] Referring to the drawings, a vehicle (100) according to an embodiment of the present disclosure may include a battery (205) that supplies power, a motor driving device (200) that receives power from the battery (205), a motor (250) that is driven and rotated by the motor driving device (200), front wheels (150) and rear wheels (155) that are rotated by the motor (250), a front suspension device (160) and a rear suspension device (165) that block vibrations of the road surface from being transmitted to the vehicle body, and an inclination detection unit (190) that detects an inclination angle of the vehicle body. Meanwhile, a driving gear (not shown) that converts the rotational speed of the motor (250) based on a gear ratio may be additionally provided.

[0037] The inclination detection unit (190) detects the inclination angle of the vehicle body, and the detected inclination angle is input to the electronic control unit (410) described later. The inclination detection unit (190) can be implemented with a gyro sensor or a horizontal gauge sensor, etc.

[0038] Meanwhile, in the drawing, the inclination detection unit (190) is depicted as being placed on the battery (205), but is not limited thereto, and may be placed on the front wheel (150), the rear wheel (155), or both the front wheel (150) and the rear wheel (155).

[0039] The battery (205) supplies power to the motor drive device (200). In particular, it supplies direct current power to the capacitor (C) in the motor drive device (200).

[0040] Such a battery (205) may be formed by a set of multiple unit cells. The multiple unit cells may be managed by a battery management system (BMS) to maintain a constant voltage, and may discharge a constant voltage by the battery management system.

[0041] For example, the battery management system can detect the voltage (Vbat) of the battery (205) and transmit it to an electronic control unit (not shown) or an inverter control unit (250) within the motor drive device (200), and when the battery voltage (Vbat) falls below a lower limit, the battery can be supplied with DC power stored in a capacitor (C) within the motor drive device (200). In addition, when the battery voltage (Vbat) rises above an upper limit, the battery management system can also be supplied with DC power to a capacitor (C) within the motor drive device (200).

[0042] The battery (205) is preferably composed of a secondary battery that can be charged and discharged, but is not limited thereto.

[0043] The motor drive device (200) receives direct current power from the battery (205) through the power input cable (120). The motor drive device (200) converts the direct current power received from the battery (205) into alternating current power and supplies it to the motor (250). The converted alternating current power may be three-phase alternating current power. The motor drive device (200) can supply three-phase alternating current power to the motor (250) through the three-phase output cable (125) provided in the motor drive device (200).

[0044] The motor drive device (200) of Fig. 1 illustrates a three-phase output cable (125) composed of three cables, but three cables may be provided within a single cable.

[0045] Meanwhile, the motor driving device (200) according to the embodiment of the present disclosure is described later in FIG. 3.

[0046] The motor (250) includes a stator (130) that is fixed and does not rotate, and a rotor (135) that rotates. The motor (250) is equipped with an input cable (140) so that it can receive AC power supplied from the motor driving device (200).

[0047] The motor (250) may be, for example, a three-phase motor, and when a voltage-variable / frequency-variable AC power source is applied to the coils of each phase's stator, the rotational speed of the rotor varies based on the applied frequency.

[0048] The motor (250) can take various forms, such as an induction motor, a BLDC motor (blushless DC motor), and a reluctance motor.

[0049] Meanwhile, a drive gear (not shown) may be provided on one side of the motor (250). The drive gear converts the rotational energy of the motor (250) based on a gear ratio. The rotational energy output from the drive gear is transmitted to the front wheels (150) and / or the rear wheels (155) to move the vehicle (100).

[0050] The front suspension (160) and rear suspension (165) support the front wheels (150) and rear wheels (155) respectively with respect to the vehicle body. The vertical directions of the front suspension (160) and rear suspension (165) are supported by springs or damping mechanisms to prevent road vibrations from reaching the vehicle body.

[0051] The front wheels (150) may further be equipped with a steering device (not shown). The steering device is a device that controls the direction of the front wheels (150) to drive the vehicle (100) in the direction intended by the driver.

[0052] Meanwhile, although not shown in the drawing, the vehicle (100) may further include an electronic controller for controlling electronic devices throughout the vehicle. The electronic controller (not shown) controls each device so that it can operate, display, etc. In addition, it may also control the battery management system described above.

[0053] In addition, the electronic control unit (not shown) can generate driving command values ​​according to various driving modes (driving mode, reverse mode, neutral mode, parking mode, etc.) based on detection signals from an inclination detection unit (not shown) that detects an inclination of the vehicle (100), a speed detection unit (not shown) that detects a speed of the vehicle (100), a brake detection unit (not shown) according to the operation of the brake pedal, an accelerator detection unit (not shown) according to the operation of the accelerator pedal, etc. The driving command value at this time can be, for example, a torque command value or a torque command value.

[0054] Meanwhile, the vehicle (100) according to the embodiment of the present disclosure may be a concept that includes a pure electric vehicle using a battery and a motor, as well as a hybrid electric vehicle using a battery and a motor while using an engine.

[0055] At this time, the hybrid electric vehicle may further be equipped with a switching means capable of selecting at least one of a battery and an engine, and a transmission.

[0056] Meanwhile, hybrid electric vehicles can be divided into a series method that converts mechanical energy output from the engine into electrical energy to drive the motor, a parallel method that simultaneously uses mechanical energy output from the engine and electrical energy from the battery, and a series-parallel method that combines the two.

[0057] FIG. 2 is an example of a vehicle drive system according to one embodiment of the present disclosure.

[0058] Referring to the drawing, a vehicle driving system (10) according to one embodiment of the present disclosure may include a vehicle (100) and a server (500).

[0059] Here, the server (500) may be a server operated by the manufacturer of the motor drive device (200) or the vehicle (100), or may correspond to a mobile terminal of the driver of the motor drive device (200) or the vehicle (100).

[0060] Meanwhile, the vehicle (100) may be equipped with an input unit (120), a communication unit (130), a memory (140), a control unit (170), a motor drive unit (200), a battery (205), and a power supply unit (195).

[0061] The input unit (120) is equipped with operation buttons, keys, etc., and can output input signals for turning the power on / off of the vehicle (100), setting operation, etc.

[0062] The communication unit (130) can exchange data with peripheral devices, such as a server (500), wired or wirelessly, or wirelessly with a remote server, etc. For example, it can perform mobile communication such as 4G or 5G, infrared (IR) communication, RF communication, Bluetooth communication, Zigbee communication, WiFi communication, etc.

[0063] Meanwhile, the memory (140) of the vehicle (100) can store data necessary for the operation of the vehicle (100). For example, data regarding the operation time and operation mode of the driving unit (200) can be stored.

[0064] Additionally, the memory (140) of the vehicle (100) can store management data including power consumption information of the vehicle, recommended driving information, current driving information, and management information.

[0065] Additionally, the memory (140) of the vehicle (100) can store diagnostic data including vehicle operation information, driving information, and error information.

[0066] The control unit (170) can control each unit within the vehicle (100). For example, the control unit (170) can control the input unit (120), the communication unit (130), the memory (140), the driving unit (200), etc.

[0067] The power supply unit (195) can convert the level of direct current power from the battery (205) and supply the converted direct current power to each unit in the vehicle (100).

[0068] To this end, the power supply unit (195) may be equipped with a converter (530) that converts the level of the direct current power from the battery (205). For example, the converter (530) may output a direct current power of approximately 12 V depending on the level of the direct current power.

[0069] Meanwhile, the converter (530) converts the level of direct current power, so it can also be called a power conversion device.

[0070] Meanwhile, the converter (530) or power conversion device according to an embodiment of the present disclosure may include a transformer. This is described with reference to FIG. 4 and below.

[0071] The motor drive unit (200) may be referred to as a motor drive device as a drive unit for driving the motor (250).

[0072] A motor driving device (200) according to an embodiment of the present disclosure comprises an inverter (420) having a plurality of switching elements and outputting AC power to a motor (250), an output current detection unit (E) detecting an output current (io) flowing in the motor (250), and current information (id, iq) and a torque command value (T) based on the output current (io) detected by the output current detection unit (E). * ), it may include an inverter control unit (430) that outputs a switching control signal to the inverter (420).

[0073] Meanwhile, current information (id, iq) and torque command (T) based on the output current (io) * ) can be transmitted to an external server (500), and the current command value (i) from the server (500) * d,i * q) may be received. And, based on the current command value received from the communication unit (130), the inverter control unit (430) may output a switching control signal to the inverter (420).

[0074] Accordingly, the motor (250) can be driven based on the current command value corresponding to the maximum torque calculated in real time by the server (500). Therefore, maximum torque driving of the motor (250) becomes possible.

[0075] Meanwhile, the communication unit (130) in the motor driving device (200) according to the embodiment of the present disclosure provides current information (id, iq), torque command value (T * ), and voltage information regarding the detected DC voltage (Vdc) can be transmitted to the server (500). Accordingly, maximum torque operation of the motor (250) under various conditions becomes possible.

[0076] Meanwhile, the detailed operation of the motor driving device (200) is described with reference to FIG. 3.

[0077] Fig. 3 illustrates an example of the internal convexity of the motor drive device of Fig. 2.

[0078] Referring to the drawings, a motor driving device (200) according to an embodiment of the present disclosure may include a converter (410) for converting the level of direct current power from a battery (205), an inverter (420) having a plurality of switching elements (not shown) and outputting alternating current power to the motor (250), and an inverter control unit (430) for controlling the inverter (420), as a driving device for driving a motor (250). In addition, the motor driving device may include a memory (270) for providing various stored data to the inverter control unit (430).

[0079] Meanwhile, the converter (410) converts the level of direct current power, so it can also be called a power conversion device.

[0080] Meanwhile, the converter (410) or power conversion device according to an embodiment of the present disclosure may include a transformer. This is described with reference to FIG. 4 and below.

[0081] Meanwhile, the motor driving device (200) according to the embodiment of the present disclosure may further include a capacitor (not shown) that stores the dc voltage (Vdc) which is the input terminal of the inverter (420), a dc voltage detection unit (not shown) that detects the dc voltage (Vdc), and an output current detection unit (E) that detects the output current flowing to the motor (250).

[0082] According to an embodiment of the present disclosure, the motor (250) may be a three-phase motor driven by an inverter (420).

[0083] Meanwhile, the inverter control unit (430) can output a switching control signal (Sic) to the inverter (420) based on a current command value corresponding to the calculated maximum torque. Accordingly, maximum torque driving of the motor (250) becomes possible.

[0084] The inverter control unit (430) according to an embodiment of the present disclosure calculates current information and a torque command value in real time, calculates a current command value based on the torque command value, and drives the motor (250) using the current command value. Accordingly, accuracy for high-efficiency driving is improved.

[0085] The inverter control unit (430) calculates a current command value based on current information, a torque command value, and a detected DC terminal voltage (Vdc), and can drive the motor (250) using the current command value. Accordingly, accuracy for high-efficiency driving is improved.

[0086] FIGS. 4 to 7 are drawings for reference in the description of the main configuration of a transformer according to one embodiment of the present disclosure.

[0087] Fig. 4 is an exploded perspective view of the main components of a transformer according to an embodiment of the present disclosure. Figs. 5 and 6 illustrate a top view and a side view, respectively, of a planar type two transformer structure with PCB winding according to an embodiment of the present disclosure, illustrating the current direction and magnetic flux direction. Fig. 7 is a combination diagram of the main components of a transformer according to an embodiment of the present disclosure.

[0088] Referring to FIGS. 4 to 7, the transformer (600a) (600) includes a first core (610) and a multi-circuit board (700).

[0089] In the multi-circuit board (700), a conductive pattern is formed through which a current flows to generate magnetic flux in the first core (610), and the first core (610) can serve as a passage for the magnetic flux.

[0090] The first core (610) includes a base (611), a first leg (612) protruding from the base (611), a second leg (613), and a third leg (614). The third leg (614) is positioned between the first leg (612) and the second leg (613). The first leg (612), the second leg (613), and the third leg (614) may protrude in the same direction from the base (611). The first leg (612), the second leg (613), and the third leg (614) may protrude in the same direction from the base (611) such that the gap between the third leg (614) and the first leg (612) and the gap between the third leg (614) and the second leg (613) are the same.

[0091] Additionally, the first leg (612), the second leg (613), and the third leg (614) may have cross-sections of the same shape. For example, the first leg (612), the second leg (613), and the third leg (614) may have cross-sections of a circle or a square. Although the present specification exemplifies a case where the first leg (612), the second leg (613), and the third leg (614) have cross-sections of a square, the present disclosure is not limited thereto.

[0092] According to an embodiment of the present disclosure, the cross-sectional area of ​​the third leg (614) is smaller than the sum of the cross-sectional areas of the first leg (612) and the second leg (613). The cross-sectional area of ​​the central third leg (614) may be larger than the cross-sectional area of ​​either the first leg (612) or the second leg (613) at the outer side, and smaller than the sum of the cross-sectional areas of the two legs (612, 613).

[0093] For example, if the cross-sections of the legs (611, 613, 614) are rectangular and the cross-sectional lengths (L) of the legs (611, 613, 614) are the same, the cross-sectional areas are determined according to the cross-sectional widths (d1, d2) of the legs (611, 613, 614).

[0094] The width (d2) of the third leg (614) may be greater than one time and less than two times the width (d1) of the first leg (612) and the second leg (613) of the outer portion. Even when the widths of the first leg (612) and the second leg (613) are different, the width (d2) of the third leg (614) is less than the sum of the widths of the first leg (612) and the second leg (613). In addition, the width (d2) of the third leg (614) is greater than the width of the first leg (612) and greater than the width of the second leg (613). Accordingly, the cross-sectional area (A2) of the third leg (614) is smaller than the sum of the cross-sectional area (A1) of the first leg (612) and the cross-sectional area (A1) of the second leg (613), and larger than the cross-sectional area (A1) of the first leg (612) and the cross-sectional area (A1) of the second leg (613).

[0095] Meanwhile, the transformer (600) further includes a second core (620) facing the first core (610). For example, the first core (610) may be an upper core and the second core (620) may be a lower core. Conversely, the first core (610) may be a lower core and the second core (620) may be an upper core.

[0096] Unlike the example in the drawing, the first core (610) and the second core (620) may be configured asymmetrically. More preferably, by configuring the second core (620) in a flat shape, unlike the first core (610), the size of the transformer (600) can be made smaller and its weight can also be reduced significantly.

[0097] Meanwhile, a plurality of conductive patterns are formed on the multi-circuit board (700). The plurality of conductive patterns are formed so that the magnetic flux in the third leg (614) is offset. Accordingly, the third leg (614) can be made smaller. According to one embodiment of the present disclosure, two transformers can be configured using only one core by considering the direction of the magnetic flux flowing in the two transformers. This can reduce the overall volume of the transformer (600), resulting in a cost-saving effect.

[0098] A multi-circuit board (700) may include a plurality of circuit boards (710, 720, 730, 740) that are stacked in a vertical direction.

[0099] A multi-circuit board (700) may have at least some of the circuit boards (710, 720, 730, 740) formed with windings having a predetermined pattern. The windings may be implemented on a printed circuit board (PCB). The windings may be formed by forming a pattern using a conductive material on an insulating material substrate. The windings may be formed as a conductive pattern on one surface of the circuit boards (710, 720, 730, 740).

[0100] The multi-circuit board (700) may include a primary side first layer board (710) and a second layer board (720). In addition, the multi-circuit board (700) may include a secondary side top layer board (710) and a bottom layer board (720). The arrangement order of the primary-secondary side boards may be changed.

[0101] Meanwhile, corresponding to the shape of the first core (610), the circuit boards (710, 720, 730, 740) may include an opening through which at least the third leg (614) of the first core (610) passes. Alternatively, the circuit boards (710, 720, 730, 740) may further include openings for the other legs (612, 613). In FIG. 4, the top layer board (710) and the bottom layer board (720) may include one opening, and the first layer board (710) and the second layer board (720) may include three openings.

[0102] The multi-circuit board (110) may include a first layer (710) including a first current pattern (710p) flowing in a first direction on one side of the third leg (614) and a second layer (720) including a second current pattern (720p) flowing in the first direction on the other side of the third leg (614). That is, current flows in the same direction on both sides of the third leg (614). The currents flowing in the same direction on both sides of the third leg (614) generate magnetic flux in opposite directions according to the right-hand screw rule, and the magnetic flux cancels out on the third leg (614).

[0103] As described with reference to Figures 11 and 12, configuring two transformers operating at the same timing typically requires two core sets. This leads to increased volume and cost, and can be seen as a major factor hindering the configuration of automotive systems requiring high power density.

[0104] The largest components of a transformer are the windings and core. According to one embodiment of the present disclosure, by considering the magnetic flux flow when two transformers operate simultaneously and canceling out each other's magnetic flux, the minimum cross-sectional area of ​​the required core can be minimized. This not only allows for the selection of a core with a smaller effective cross-sectional area, but also allows for the replacement of two core sets with a single core set.

[0105] The first current pattern (710p) can be formed so that the current flows into the outer part of the first leg (612), surrounds the first leg (612) and the third leg (614), and then passes between the third leg (614) and the second leg (613).

[0106] The second current pattern (720p) can be formed so that the current flows into the outer part of the second leg (613), surrounds the second leg (613) and the third leg (614), and then passes between the third leg (614) and the first leg (612).

[0107] In the third leg (614), the magnetic flux generated by the current flowing in the first current pattern (710p) and the magnetic flux generated by the current flowing in the second current pattern (720p) can be canceled out.

[0108] When current flows in the current direction shown in FIGS. 5 and 6, magnetic flux flows in the incoming direction (x) according to the right-hand screw rule in the first leg (612) and the third leg (614), and magnetic flux flows in the outgoing direction (◎) in the third leg (614) and the second leg (613).

[0109] In the third leg (614), the magnetic flux in the incoming direction (x) and the magnetic flux in the outgoing direction (◎) cancel each other out, and through this, the total effective cross-sectional area (Ae) of the third leg (614) can be configured to be small. In a transformer, a design is required so that the magnetic flux does not saturate, and one of the most important factors for this is the effective cross-sectional area (Ae) value. It is typical to select a core having a core effective cross-sectional area (Ae) such that the magnetic flux density induced in the core during normal operation is below a specific value (B_sat). Therefore, if the magnetic flux density induced in the core can be further reduced through magnetic flux cancellation, a core having a smaller core effective cross-sectional area (Ae) can be selected, and the volume of the entire magnetic body can be reduced.

[0110] In addition, the first current pattern (710p) and the second current pattern (720p) are formed so that at least some sections surround or pass between two or more of the legs (612, 613, 614), thereby providing a common use portion and reducing the overall pattern length. Accordingly, power consumption, heat generation, and core loss due to an increase in the conductive pattern length can be reduced.

[0111] Meanwhile, a via hole (750) is formed in the first layer (710) and the second layer (720), and the first current pattern (710p) and the second current pattern (720p) can be electrically connected through the via hole (750) using a conductive material (755). For example, the second current pattern (720p) can be connected to the first current pattern (710p) at the outer edge of the second leg (613).

[0112] FIGS. 8 to 10 are drawings for reference in the description of the main configuration of a transformer according to an embodiment of the present disclosure. In FIGS. 8 to 10, parts that are identical / similar to those in the embodiments of FIGS. 4 to 7 are denoted by the same numbers.

[0113] Figures 8 and 9 illustrate a top view and a side view, respectively, of a planar type two transformer structure with PCB winding according to an embodiment of the present disclosure, illustrating the current direction and the magnetic flux direction. Figure 10 is a schematic diagram of the main components of a transformer according to an embodiment of the present disclosure.

[0114] Referring to FIGS. 8 to 10, a transformer (600b) according to one embodiment of the present disclosure includes a third core (610a) and a fourth core (610b) arranged side by side, and a multi-circuit board (700) having a plurality of conductive patterns formed thereon, through which a current that generates magnetic flux flows in the third core (610a) and the fourth core (610b).

[0115] The third core (610a) and the fourth core (610b) may each include two legs having different cross-sectional areas. For example, the third core (610a) may include a first leg (612) and a third-first leg (810) having a smaller width than the first leg (612). In addition, the fourth core (610b) may include a second leg (613) and a third-second leg (820) having a smaller width than the second leg (613).

[0116] Among the four legs (611, 612, 810, 820) of the third core (610a) and the fourth core (610b), a plurality of conductive patterns can be formed in the two legs (810, 820) located in the center so that the magnetic flux is offset in the two legs located in the center on the multi-circuit board (700).

[0117] Accordingly, among the four legs (611, 612, 810, 820) of the third core (610a) and the fourth core (610b), the cross-sectional areas of the two legs (810, 820) located in the center may be smaller than the cross-sectional areas of the remaining two legs (611, 612).

[0118] The width (d3) of the two centrally located legs (810, 820) may be greater than one time and less than two times the width (d1) of the outer legs (611, 612). Accordingly, the cross-sectional area (A3) of the central legs (810, 820) becomes smaller than the sum of the cross-sectional areas (A1) of the outer legs (611, 612).

[0119] Meanwhile, the transformer (600b) further includes an upper or lower core (620a, 620b) facing the third and fourth cores (610a, 610b).

[0120] Meanwhile, a plurality of conductive patterns are formed in the central legs (810, 820). The plurality of conductive patterns are formed so that the magnetic flux in the central legs (810, 820) is offset. Accordingly, the central legs (810, 820) can be made smaller.

[0121] The multi-circuit board (700) may include a primary side first layer board (710) and a second layer board (720). In addition, the multi-circuit board (700) may include a secondary side top layer board (710) and a bottom layer board (720). The arrangement order of the primary-secondary side boards may be changed.

[0122] Meanwhile, corresponding to the shape of the first core (610), the circuit board (710, 720, 730, 740) may include an opening through which at least the third leg (614) of the first core (610) passes. Alternatively, the circuit board (710, 720, 730, 740) may further include an opening for the other leg (612, 613).

[0123] The multi-circuit board (110) may include a first layer (710) including a first current pattern (710p) flowing in a first direction on one side of the central leg (810, 820) and a second layer (720) including a second current pattern (720p) flowing in the first direction on the other side of the central leg (810, 820). That is, current flows in the same direction on both sides of the central leg (810, 820). The currents flowing in the same direction on both sides of the central leg (810, 820) generate magnetic flux in the opposite direction by the right-hand screw rule, and the magnetic flux is canceled on the central leg (810, 820).

[0124] The first current pattern (710p) can be formed so that the current flows to the outside of the first leg (612), surrounds the first leg (612) and the first central leg (810), and then passes between the second central leg (820) and the second leg (613).

[0125] The second current pattern (720p) can be formed so that the current flows to the outside of the second leg (613), surrounds the second central leg (820) and the third leg (614), and then passes between the third leg (614) and the first central leg (810).

[0126] In the central leg (810, 820), the magnetic flux generated by the current flowing in the first current pattern (710p) and the magnetic flux generated by the current flowing in the second current pattern (720p) can be canceled out.

[0127] When current flows in the current direction shown in FIGS. 9 and 10, magnetic flux flows in the incoming direction (x) according to the right-hand screw rule in the first leg (612) and the second central leg (820), and magnetic flux flows in the outgoing direction (◎) in the first central leg (810) and the second leg (613).

[0128] In the central legs (810, 820), the magnetic flux in the incoming direction (x) and the outgoing direction (◎) cancel each other out, and through this, the total effective cross-sectional area (Ae) of the central legs (810, 820) can be configured to be small.

[0129] In addition, the first current pattern (710p) and the second current pattern (720p) are formed so that at least some sections surround or pass between two or more of the legs (612, 613, 810, 820), thereby providing a common use portion and reducing the overall pattern length. Accordingly, power consumption, heat generation, and core loss due to an increase in the conductive pattern length can be reduced.

[0130] Although the preferred embodiments of the present disclosure have been illustrated and described above, the present disclosure is not limited to the specific embodiments described above, and various modifications may be made by a person skilled in the art to which the present disclosure pertains without departing from the gist of the present disclosure as claimed in the claims, and such modifications should not be understood individually from the technical idea or prospect of the present disclosure.

Claims

1. First core; and, A multi-circuit board having a conductive pattern formed thereon, through which a current that generates magnetic flux flows in the first core; The above first core, base; First and second legs protruding from the base; A third leg disposed between the first leg and the second leg; A transformer characterized in that the cross-sectional area of ​​the third leg is smaller than the sum of the cross-sectional areas of the first leg and the second leg.

2. In paragraph 1, The above multi-circuit board, A first layer including a first current pattern flowing in a first direction on one side of the third leg, A transformer comprising a second layer including a second current pattern flowing in the first direction on the other side of the third leg.

3. In paragraph 2, The above first current pattern is, A transformer in which current flows into the outer portion of the first leg, surrounds the first leg and the third leg, and passes between the third leg and the second leg.

4. In paragraph 2, The above second current pattern is, A transformer in which current flows into the outer portion of the second leg, surrounds the second leg and the third leg, and passes between the third leg and the first leg.

5. In paragraph 2, The above second current pattern is, A transformer connected to the first current pattern at the outer edge of the second leg.

6. In paragraph 1, A transformer in which the magnetic flux generated by the current flowing in the first current pattern and the magnetic flux generated by the current flowing in the second current pattern are canceled in the third leg.

7. In paragraph 1, A transformer further comprising a second core facing the first core.

8. A first core including a base, a first leg and a second leg protruding from the base, and a third leg disposed between the first leg and the second leg; and, A multi-circuit board having a plurality of conductive patterns formed thereon, through which a current that generates magnetic flux flows in the first core; A transformer in which the plurality of conductive patterns are formed so that the magnetic flux is canceled in the third leg.

9. In paragraph 8, A transformer characterized in that the cross-sectional area of ​​the third leg is smaller than the sum of the cross-sectional areas of the first leg and the second leg.

10. In paragraph 8, The above multi-circuit board, A first layer including a first current pattern flowing in a first direction on one side of the third leg, A transformer comprising a second layer including a second current pattern flowing in the first direction on the other side of the third leg.

11. In paragraph 10, The above first current pattern is, A transformer in which current flows into the outer portion of the first leg, surrounds the first leg and the third leg, and passes between the third leg and the second leg.

12. In paragraph 10, The above second current pattern is, A transformer in which current flows into the outer portion of the second leg, surrounds the second leg and the third leg, and passes between the third leg and the first leg.

13. In paragraph 10, The above second current pattern is, A transformer connected to the first current pattern at the outer edge of the second leg.

14. The third and fourth cores are arranged in parallel; and, A multi-circuit board having a plurality of conductive patterns formed thereon, through which a current flows to generate magnetic flux in the third core and the fourth core; A transformer characterized in that the third core and the fourth core each include two legs having different cross-sectional areas.

15. In paragraph 14, A transformer characterized in that, among the four legs of the third core and the fourth core, the cross-sectional area of ​​the two legs located in the center is smaller than the cross-sectional areas of the remaining two legs.

16. A transformer in which the above plurality of conductive patterns are formed so that the magnetic flux is canceled in the two legs located in the center.

17. A power conversion device comprising a transformer according to any one of claims 1 to 16.

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