Inductor Device

Abstract

Provided are an inductor device in which variability between the inductances of two magnetically coupled reactors is suppressed, and a direct current converting device employing the inductor device.　The inductor device comprises a core including a first leg portion having a first gap, and a second leg portion provided with a second gap with the same positional relationship as the first gap, a first bobbin attached to the first leg portion, a first coil and a second coil wound separately on the first bobbin, a second bobbin which is attached to the second leg portion and which has substantially the same shape as the first bobbin, and a third coil and a fourth coil wound separately on the second bobbin, wherein, when the first coil, the second coil, the third coil, and the fourth coil are seen from the front, two coils in corresponding positions in an X-shape are connected to one another in series.

Description

[Technical Field]

[0001] The present technology relates to an inductor device having, for example, two inductors. [Background technology]

[0002] The applicant of the present application has previously proposed a DC converter as described in Patent Document 1. Figure 15 of Patent Document 1 describes a configuration in which reactors of two converters are magnetically coupled. With this configuration, the two reactors can be realized by a single inductor device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 208936 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when two reactors are configured with separate windings, the gap fringing phenomenon causes variations in the inductance of the two reactors, which can result in an imbalance in the loads of the two converters in the DC converter, and the variations in inductance can cause currents with unnecessary frequency components to flow in the primary resonant current, potentially generating unwanted noise.

[0005] Therefore, an object of the present technology is to provide an inductor device in which variations in inductance between two coils wound separately around a common core are suppressed, and a DC converter using such an inductor device. [Means for solving the problem]

[0006] This technology is A first leg having an E-shaped cross section and integrally including a first common leg, a first leg, and a second leg. The core and a second core having an E-shaped cross section, the second core integrally including a second shared leg having an end face abutting against the first shared leg, a third leg facing the first leg across a first gap, and a fourth leg facing the second leg across a second gap having a width equal to the first gap; First leg and the third leg to Inserted a first bobbin, a first coil and a second coil wound separately on a first bobbin; On the second and fourth legs Inserted a second bobbin having substantially the same shape as the first bobbin; a third coil and a fourth coil wound separately on a second bobbin; Equipped with When the first coil, second coil, third coil, and fourth coil are viewed from the front, two coils at corresponding positions in an X-shape are connected in series. R, a clearance in the height direction exists at a mounting position of the first bobbin relative to the first leg and the third leg, and at a mounting position of the second bobbin relative to the second leg and the fourth leg, The first bobbin and the second bobbin are assembled so as to be displaced in the same direction and brought into contact with one of the first core and the second core. It is an inductor device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a connection diagram of a current resonant converter to which the present technology can be applied. [Figure 2] FIG. 2 is a waveform diagram for explaining the drive signal. [Figure 3] FIG. 3 is a mode transition diagram of the operation modes of the switch element in the present technology. [Figure 4] FIG. 4 is a waveform diagram showing the current waveform and voltage waveform of the element in each operation mode. [Figure 5] FIG. 5 is a waveform diagram showing an output current waveform of the present technology. [Figure 6] FIG. 6 is a cross-sectional view of an example of an inductor device. [Figure 7] 7A, 7B, and 7C are waveform diagrams respectively showing the primary resonant current waveform of a DC converter when there is variation in reactor inductance, the original primary resonant current waveform, and the current difference. [Figure 8] FIG. 8 is a graph for explaining the influence of variations in reactor inductance on the load balance. [Figure 9] FIG. 9 is a cross-sectional view of an inductor device having a bifilar winding configuration. [Figure 10] FIG. 10 is a waveform diagram showing a current waveform when an inductor device with a bifilar winding configuration is used. [Figure 11] FIG. 11 is a cross-sectional view of an inductor device according to an embodiment of the present technology. [Figure 12] FIG. 12 is a perspective view of an embodiment of the present technology. [Figure 13] FIG. 13 is an exploded perspective view of an embodiment of the present technology. [Figure 14] FIG. 14 is a connection diagram illustrating a connection of a coil according to an embodiment of the present technology. [Figure 15] 15A and 15B are a bottom view and a perspective view for explaining a terminal pin according to one embodiment of the present technology. [Figure 16] 16A, 16B, and 16C are schematic diagrams used to explain the coil arrangement used in the simulation. [Figure 17] 17A and 17B are schematic diagrams used to explain the coil arrangement used in the simulation. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present technology will be described with reference to the drawings. Note that the embodiments described below are preferred specific examples of the present technology, and the content of the present technology is not limited to these embodiments. In addition, in the following description, in order to prevent the illustrations from becoming complicated, reference symbols may be assigned to only some of the components, or some of the components may be shown in a simplified form.

[0009] To facilitate understanding of one embodiment, a previously proposed DC converter will be described below. This DC converter is a current-resonant type (LLC) converter. In FIG. 1, Vin is an input power supply, Q1 is a high-side switching element such as a MOSFET, and Q2 is a low-side switching element such as a MOSFET. A diode and a capacitance exist in parallel as parasitic elements between the drain and source of the switching element Q1. A diode and a capacitance exist in parallel as parasitic elements between the drain and source of the switching element Q2. A control unit supplies drive signals to the gates of the switching elements Q1 and Q2, causing the switching elements Q1 and Q2 to perform switching operations.

[0010] A resonant circuit is connected between the source of the switching element Q2 and the connection point between the source of the switching element Q1 and the drain of the switching element Q2. The resonant circuit is made up of a series connection of a resonant reactor Lr1, a primary winding Np of a transformer, and a resonant capacitor Cr1. A reactor Lm1 is connected in parallel to the primary winding Np of the transformer. The reactor Lm1 is, for example, an exciting inductance component of the transformer.

[0011] The secondary winding Ns of the transformer is divided into two inductances, one end of the secondary winding is connected to the output terminal via diode D1, and the other end of the secondary winding is connected to the output terminal via diode D2. The connection midpoint of the secondary windings is taken out as the output terminal, and a capacitance Cout is connected between the output terminals. A load is connected to the output terminal. Diodes D1 and D2 and capacitance Cout form a rectifier that rectifies the voltage generated in the secondary winding of the transformer.

[0012] In the converter described above, drive signals of opposite phases are supplied to the gates of the switching elements Q1 and Q2, causing these switching elements Q1 and Q2 to perform differential switching operations, and an output current I1 flows.

[0013] Two of the above converters are connected in parallel. The other converter includes switch elements Q3 and Q4, reactors Lr2 and Lm2, a resonant capacitor Cr2, a transformer, and diodes D3 and D4. An output current I2 flows through the other converter.

[0014] A control circuit 10 is provided, which generates drive signals Out1, Out2, Out3, and Out4 that control the on / off of the switching elements Q1 to Q4 of each converter. The output voltage output by the smoothing circuit is fed back to the feedback FB input of the control circuit 10. This feedback controls the output voltage to a constant value. The control circuit 10 controls the on / off of the switching elements so that there is a π shift between the two converters. Figure 2 shows the drive signals Out1, Out2, Out3, and Out4 that control the on / off of the switching elements Q1 to Q4.

[0015] There are eight operating modes (Mode 1, Mode 2, Mode 3, ..., Mode 8) depending on the relationship between the on and off operations of the switch elements Q1 to Q4. Figure 3 shows the current paths formed including the switch elements that are on in each mode. Figure 4 shows the voltage and current of each element at that time. The voltage and current waveforms in each mode are the same as those of existing resonant converters. In a resonant converter, two switch elements connected in series are alternately turned on and off with a phase difference of π. Since the two converters are operated with a phase difference of π, Q1 and Q4, and Q2 and Q3 in the figure are turned on and off simultaneously. Furthermore, the output currents I1 and I2 of each converter and the sum of the two output currents (I1 + I2) are shown in Figure 5.

[0016] Each operation mode will be explained in turn. For simplicity, the source of each of the switch elements Q1 to Q4 will be denoted as S and the drain as D. Mode 1: Current flows from S to D of Q1 due to the energy stored in Lm1. Also, current flows from S to D of Q4 due to the energy stored in Lm2. At this time, turning on Q1 and Q4 while the parasitic diodes of each switch element are conducting results in zero-volt switching. At the same time, energy is transferred to the secondary side from the secondary-side rectifier.

[0017] Mode 2: The input voltage Vin causes current to flow from D to S of Q1, exciting Lm1 and transmitting power to the secondary side. Also, the voltage stored in Cr2 causes current to flow from D to S of Q4, exciting Lm2 and transmitting power to the secondary side.

[0018] Mode 3: The voltage across Lm1 and Lm2 drops below the value obtained by multiplying the secondary voltage by the transformer turns ratio, and power transmission to the secondary side ceases.

[0019] Mode 4: Q1 and Q4 are turned off. The energy stored in Lm1 charges the parasitic capacitance of Q1 and discharges the parasitic capacitance of Q2, causing the voltage across Q1 to change to Vin and the voltage across Q2 to 0. Similarly, the energy stored in Lm2 charges the parasitic capacitance of Q4 and discharges the parasitic capacitance of Q3, causing the voltage across Q4 to change to Vin and the voltage across Q3 to 0.

[0020] Mode 5: The energy stored in Lm1 causes current to flow from S to D of Q2. Also, the energy stored in Lm2 causes current to flow from S to D of Q3. At this time, turning on Q2 and Q3 while the parasitic diodes of each switch element are conducting results in zero-volt switching. At the same time, energy is transferred to the secondary side from the secondary-side rectifier.

[0021] Mode 6: The energy stored in Cr1 causes current to flow from D to S of Q2, exciting Lm1 and transmitting power to the secondary side. Also, current flows from Vin from D to S of Q3, exciting Lm2 and transmitting power to the secondary side.

[0022] Mode 7: The voltage across Lm1 and Lm2 drops below the value obtained by multiplying the secondary voltage by the transformer turns ratio, and power transmission to the secondary side ceases.

[0023] Mode 8: Q1 and Q4 are turned off. The energy stored in Lm1 charges the parasitic capacitance of Q2 and discharges the parasitic capacitance of Q1, causing the voltage across Q2 to change to Vin and the voltage across Q1 to zero. Similarly, the energy stored in Lm2 charges the parasitic capacitance of Q3 and discharges the parasitic capacitance of Q4, causing the voltage across Q3 to change to Vin and the voltage across Q4 to zero.

[0024] The voltage and current waveforms of the reactor and transformer of the resonant converter shown in Figure 1 are similar figures with a phase difference of π and a positive-negative inversion. Because the two converters are controlled with a phase difference of π, the voltage and current waveforms of the reactor and transformer are similar figures with a positive-negative inversion. Therefore, as shown in Figure 1, the reactor and transformer can be magnetically coupled by reversing their polarities.

[0025] This makes it possible to achieve the reduction of common-mode noise produced by two converters with what appears to be a single reactor or transformer, making it possible to achieve the same effect even in small-scale DC converters. Furthermore, by magnetically coupling the reactors, it is easy to balance the operation of the two resonant converters.

[0026] An inductor device according to an embodiment of the present technology is applied to reactors Lr1 and Lr2 in a resonant converter shown in Fig. 1. The reactors use a core (ferrite) with an air gap to suppress magnetic saturation. An inductor device having two magnetically coupled reactors is generally configured with coils that share a magnetic path, as shown in Fig. 6.

[0027] In the example of FIG. 6, a first coil N1 and a second coil N2 are wound around separators 2a, 2b, and 2c, and a bobbin 1 having a circular center hole. Separator 2b is formed at the center between separators 2a and 2c. The bobbin 1 is, for example, a resin molded product. Coil N1 is wound between separators 2a and 2b, and coil N2 is wound between separators 2b and 2c. Coils N1 and N2 are divided and wound an equal number of times.

[0028] Cores 3 and 5, which have E-shaped cross sections, have the same dimensions. The shared legs 4a and 6a of cores 3 and 5, respectively, are inserted into the center hole of bobbin 1, forming a gap where they face each other. In the gap, in an attempt to reduce magnetic resistance, the cross-sectional area through which the magnetic flux passes becomes larger than the cross-sectional area of ​​the core, causing the magnetic flux to expand (fringing phenomenon). The magnetic flux generated by this fringing phenomenon is called fringing magnetic flux.

[0029] If the center of separator 2b of bobbin 1 coincides with the center of the gap, the influence of fringing magnetic flux will be equal for coils N1 and N2. However, the space formed by core 3 and core 5 is slightly larger than bobbin 1, and a clearance exists in the height direction. When assembling to store bobbin 1, if the bobbin 1 is assembled by abutting it against the upper core 3 side as shown by the arrow in Figure 6, the position of the bobbin 1 will be shifted from the center of the gap by the amount of the clearance.

[0030] In this case, the fringing magnetic flux for coil N1 is greater than the fringing magnetic flux for coil N2 (the inductance created by coil N1 is less than the inductance created by coil N2). In this way, when an inductor is constructed using split-wound coils, the position of the bobbin, i.e., the position of the coil, cannot be controlled, and therefore variations occur in the inductance of the two inductors.

[0031] In the case of the DC converter shown in Figure 1, taking the example of a 10A 40V output, differences occur in the resonant conditions and primary current waveforms of each phase. Figure 7A shows the primary resonant current waveform when there is a 2% variation in the inductance ratio. Figure 7B shows the primary resonant current waveform when there is no variation in the inductance ratio. The primary resonant current waveform shown in Figure 7A has a difference component as shown in Figure 7C compared to the primary resonant current waveform shown in Figure 7B. This difference component could cause unnecessary noise and an imbalance in the circuit load.

[0032] Figure 8 shows the relationship between the inductance variation of reactors Lr1 and Lr2 and the load variation. When the inductance of each inductor is 67.11 μH (0% variation), both secondary load factors are 100%. In Figure 8, the open graph shows the secondary load factor of the converter including reactor Lr1, and the shaded graph shows the secondary load factor of the converter including reactor Lr2. Typically, in an inductor device manufactured with bobbin 1 biased to one side, the inductance variation is ±3%. As Figure 8 shows, when the inductance variation is ±1%, the load current changes by ±0.8%, when the inductance variation is ±2%, the load current changes by ±1.6%, and when the inductance variation is ±3%, the load current changes by ±2.4%. In this way, the load variation is related to (inductance difference x 0.8), so if the inductance difference is + / -3%, the load variation will be + / -2.4%.

[0033] To eliminate the inductance variation, it is possible to wind the two coils N1 and N2 in a bifilar fashion, as shown in Figure 9. That is, one possible method is to alternately wind the two coils N1 and N2 as a pair between separators 2a and 2c of the bobbin 1. This method has the problem that the parasitic capacitance generated in the dashed line area in Figure 9 increases because coils N1 and N2 are in close contact with each other. The line-to-line capacitance is about 10 times larger than that of the split winding shown in Figure 6. This line-to-line capacitance causes the current waveform to become unbalanced, as shown in Figure 10.

[0034] The relationship between the combinations of resonant capacitors Cr1 and Cr2, reactors Lr1 and Lr2, and variations in the primary and secondary currents is shown in Table 1. The notation "Main" refers to the converter or reactor Lr1 configured with switch elements Q1 and Q2, and "Sub" refers to the converter or reactor Lr2 configured with switch elements Q3 and Q4 (see Figure 1). Table 1 is a horizontally long table divided into four tables arranged vertically, with each row corresponding to another. As an example, the variation in the resonant capacitors is set to + / -3%.

[0035] [Table 1]

[0036] In practice, it is desirable to keep the load balance within ±5%. In Table 1, the variation in secondary current needs to be (104.9%:95.1%), which requires the variation in reactors Lr1 and Lr2 to be ±1%. To keep the reactor variation within this range, an assembly precision of, for example, 0.2 mm or less is required. However, due to specifications and manufacturing considerations, it was practically impossible to securely attach the bobbin to the core with this assembly precision.

[0037] An embodiment of the present technology that solves the problems of the conventional inductor device described above will be described. FIG. 11 is a cross-sectional view for explaining an embodiment of the present technology. A first coil N1 and a second coil N2 are wound separately around a bobbin 11 serving as a first bobbin. The bobbin 11 has ring-shaped separators 12a, 12b, and 12c on the circumferential surface of a cylinder. Separator 12b is formed at a central position between separators 12a and 12c. The bobbin 11 is, for example, a resin molded product. Coil N1 is wound between separators 12a and 12b, and coil N2 is wound between separators 12b and 12c.

[0038] A third coil N3 and a fourth coil N4 are wound separately around a bobbin 13 serving as a second bobbin. The bobbin 13 has ring-shaped separators 14a, 14b, and 14c on the circumferential surface of a cylindrical body. Separator 14b is formed in the center between separators 14a and 14c. The bobbin 13 is, for example, a resin molded product. Coil N3 is wound between separators 14a and 14b, and coil N4 is wound between separators 14b and 14c. Coils N1, N2, N3, and N4 are made of wire of the same type and dimensions, and have the same number of turns.

[0039] Bobbins 11 and 13, each wound with a coil, are attached to cores 15 and 17. Cores 15 and 17 are, for example, ferrite cores. Core 15 has an E-shaped cross section and integrally includes a central shared leg 16a and legs 16b and 16c that are provided symmetrically on the outside of shared leg 16a. Core 17 has the same shape as core 15 and integrally includes a central shared leg 18a and legs 18b and 18c that are provided symmetrically on the outside of shared leg 18a.

[0040] The end face of shared leg 16a of core 15 and the end face of shared leg 18a of core 17 abut against each other, the end face of leg 16b of core 15 and the end face of leg 18b of core 17 face each other across a first gap, and the end face of leg 16c of core 15 and the end face of leg 18c of core 17 face each other across a second gap. The widths of these gaps are all equal.

[0041] Leg 16b of core 15 and leg 18b of core 17 are inserted into the center hole of bobbin 11, and leg 16c of core 15 and leg 18c of core 17 are inserted into the center hole of bobbin 13. Fig. 11 is a front view of the first coil N1, second coil N2, third coil N3, and fourth coil N4 of the inductor device. In Fig. 11, two coils (N1 and N4, and N2 and N3) located at positions corresponding to the X shape (cross-body) are connected in series.

[0042] If the inductances formed by coils N1, N2, N3, and N4 are represented as L1, L2, L3, and L4, respectively, then when affected by fringing magnetic flux, L1 ≒ L3 and L2 ≒ L4. Therefore, the inductance of the series-connected coils N1 and N4 is (L1 + L4), and the inductance of the series-connected coils N2 and N3 is (L2 + L3). Therefore, (L1 + L4 ≒ L2 + L3).

[0043] The value of inductance (L1+L4) is set to be equal to the value of reactor Lr1 in the DC converter shown in Fig. 1, and the value of inductance (L2+L3) is set to be equal to the value of reactor Lr2 in the DC converter shown in Fig. 1. Therefore, variations in reactors Lr1 and Lr2 caused by fringing magnetic flux can be suppressed.

[0044] FIG. 12 is a perspective view of an embodiment of the present technology, and FIG. 13 is an exploded perspective view of an embodiment of the present technology. The coils N1 to N4 are depicted as cylindrical surfaces in the drawings, but are in fact formed by winding a wire a predetermined number of times. Terminal pins t1, t2, t3, and t4 protrude from the bottom of a cylindrical bobbin 11 having separators 12a, 12b, and 12c. Terminal pins t5, t6, t7, and t8 protrude from the bottom of a cylindrical bobbin 13 having separators 14a, 14b, and 14c. Ends of the coils N1 to N4 are connected to these terminal pins t1 to t8. The bobbins 11 and 13 are mounted such that their longitudinal directions are perpendicular to the printed circuit board. The terminal pins penetrate the printed circuit board and are connected to wiring patterns on the printed circuit board.

[0045] Leg 16b of core 15 and leg 18b of core 17 are cylindrical and can be inserted into the center hole of bobbin 11. Leg 16c of core 15 and leg 18c of core 17 are cylindrical and can be inserted into the center hole of bobbin 13. Shared leg 16a of core 15 is composed of divided shared legs 16a1 and 16a2, and shared leg 18a of core 17 is composed of divided shared legs 18a1 and 18a2.

[0046] As shown in FIGS. 14, 15A, and 15B, coils N1 to N4 are connected by terminal pins t1 to t8. One end of coil N1 (a black dot indicates the winding start side (polarity)) is connected to terminal pin t1, which is connected to wiring pattern 21a on a printed circuit board (not shown). The other end of coil N1 is connected to terminal pin t2, which is connected to wiring pattern 21c on the printed circuit board (not shown), and terminal pin t7 is connected to wiring pattern 21c. The other end of coil N4 is connected to terminal pin t7. One end of coil N4 (a black dot indicates the winding start side (polarity)) is connected to wiring pattern 21f. In this way, coils N1 and N4 are connected in series.

[0047] Similarly, coils N2 and N3 are connected in series. One end (black dot side) of coil N2 is connected to terminal pin t3, which is connected to wiring pattern 21b on the printed circuit board (not shown). The other end of coil N2 is connected to terminal pin t4, which is connected to wiring pattern 21d on the printed circuit board (not shown), and terminal pin t5 is connected to wiring pattern 21d. The other end of coil N3 is connected to terminal pin t5. One end (black dot side) of coil N3 is connected to wiring pattern 21e. In this way, coils N2 and N3 are connected in series. Since the inductor device is mounted vertically, it is possible to prevent the wiring patterns from crossing each other.

[0048] The series connection of the coils N1 and N4 corresponds to the reactor Lr1 in the DC converter shown in FIG. 1, and the series connection of the coils N2 and N3 corresponds to the reactor Lr2 in the DC converter shown in FIG. 1. Regarding the embodiment of the present technology described above, the layout of the coils N1 to N4 (FIG. 1 6 The simulation results of the inductance variation are shown in Figure 1. 6 , will be explained with reference to FIG. 17 and Table 2.

[0049] [Table 2]

[0050] Table 2 shows the inductance (μH) of the series connection of two coils in each layout. As examples of series connections, the inductances of the series connection of coils N1 and N3 (referred to as N1-N3 series), the series connection of coils N2 and N4 (referred to as N2-N4 series), the series connection of coils N1 and N4 (referred to as N1-N4 series), and the series connection of coils N2 and N3 (referred to as N2-N3 series) were calculated. The above-described embodiment of the present technology has the (N1-N4 series) and (N2-N3 series) configurations, and the other connections in which the upper coils are connected in series with the lower coils are configurations for comparison. Furthermore, in the simulation, the height clearance between the cores 15 and 17 and the bobbins 11 and 13 was set to 0.35 mm on one side. Each layout will now be described.

[0051] Layout #1: This is a layout in which the bobbins 11 and 13 are located in the center (clearance = 0). In this layout #1, the ratio of the difference in inductance between the two series connections (N1-N3 series) and (N2-N4 series) is 0%, and the ratio of the difference in inductance between the other two series connections (N1-N4 series) and (N2-N3 series) is also 0%.

[0052] Figure 1 6 Layout #1 shown in A: This is a layout in which the bobbins 11 and 13 are arranged in the center (clearance = 0). In this layout #1, the ratio of the difference in inductance between the two series connections (N1-N3 series) and (N2-N4 series) is 0%, and the ratio of the difference in inductance between the other two series connections (N1-N4 series) and (N2-N3 series) is also 0%.

[0053] Figure 1 6Layout #2 shown in B: This is a layout in which bobbin 11 is placed in the center and bobbin 13 is butted against the upper side. In this layout #1, the ratio of the inductance difference between the two series connections (N1-N3 series) and (N2-N4 series) is (56.402-55.438) / 55.438) is -1.7%. The ratio of the inductance difference between the other two series connections (N1-N4 series) and (N2-N3 series) is (56.341-55.499) / 56.341) is 1.5%.

[0054] Figure 1 6 Layout #3 shown in C: This is a layout in which bobbin 11 is butted against the bottom side and bobbin 13 is butted against the top side. In this layout #3, the ratio of the inductance difference between the two series connections (N1-N3 series) and (N2-N4 series) (55.909-55.932) / 55.909) is 0%. The ratio of the inductance difference between the other two series connections (N1-N4 series) and (N2-N3 series) (56.789-55.052) / 56.789) is 3.1%.

[0055] Layout #4 shown in FIG. 17A is a layout in which the bobbins 11 and 13 are butted downward. In this layout #4, the ratio of the inductance difference between the two series connections (N1-N3 series) and (N2-N4 series) is 3.1% (56.817-55.070) / 56.817). The ratio of the inductance difference between the other two series connections (N1-N4 series) and (N2-N3 series) is 0% (55.937-55.950) / 55.937). Therefore, the configuration of the present technology can reduce inductance variation.

[0056] Layout #5 shown in FIG. 17B is a layout in which the bobbins 11 and 13 are butted upward. In this layout #5, the ratio of the inductance difference between the two series connections (N1-N3 series) and (N2-N4 series) (55.009-56.782 / 55.009) is -3.2%. The ratio of the inductance difference between the other two series connections (N1-N4 series) and (N2-N3 series) (55.893-55.898 / 55.893) is 0%. Therefore, the configuration of the present technology can reduce inductance variation.

[0057] Therefore, layout #4 or layout #5, in which both bobbin 11 and bobbin 13 are displaced in the same direction and assembled so as to abut against one of first core 15 and second core 17, can suppress variations in inductance.

[0058] The above-described embodiment of the present technology can achieve the following effects. By using a core that shares a magnetic path, the installation floor space can be reduced. It is possible to realize a coupled reactor with minimized inductance variation. There is no longer a need to combine inductances by rank on the circuit side, which reduces management costs. The imbalance in the load between the two converters of the DC converter can be reduced. This can prevent current with unnecessary frequency components from flowing in the primary resonant current due to variations in inductance, thereby preventing the generation of unnecessary noise.

[0059] Although one embodiment of the present technology has been specifically described above, the present technology is not limited to the above-described embodiment, and various modifications based on the technical concept of the present technology are possible. Furthermore, the configurations, methods, processes, shapes, materials, and numerical values ​​given in the above-described embodiment are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as necessary.

[0060] The present technology can have the following configurations. (1) a core having a common leg, a first leg having a first gap, and a second leg having a second gap provided in the same positional relationship as the first gap; a first bobbin attached to the first leg; a first coil and a second coil wound separately on the first bobbin; a second bobbin attached to the second leg and having substantially the same shape as the first bobbin; a third coil and a fourth coil wound separately on the second bobbin; Equipped with An inductor device in which two coils are connected in series at positions corresponding to each other in an X shape when the first coil, the second coil, the third coil, and the fourth coil are viewed from the front. (2) the first bobbin and the second bobbin each have a first separator, a second separator, and a third separator protruding from both ends and a center portion of a cylindrical body, respectively; the first coil is wound between the first separator and the second separator of the first bobbin, the second coil is wound between the second separator and the third separator of the first bobbin; the third coil is wound between the first separator and the second separator of the second bobbin, the fourth coil is wound between the second separator and the third separator of the second bobbin, 2. The inductor device according to claim 1, wherein the inductances formed by the first coil to the fourth coil are approximately equal to each other. (3) The inductor device according to (1) or (2), wherein the first coil and the fourth coil are connected in series, and the second coil and the third coil are connected in series. (4) first and second terminal pins connected to both ends of the first coil, and third and fourth terminal pins connected to both ends of the second coil, are provided on a lower portion of the first bobbin; fifth and sixth terminal pins connected to both ends of the third coil, and seventh and eighth terminal pins connected to both ends of the fourth coil are provided on a lower portion of the second bobbin; the first coil and the fourth coil are connected in series by connecting the second terminal pin and the seventh terminal pin through a wiring pattern on a printed circuit board; The inductor device according to (3), wherein the second coil and the third coil are connected in series by connecting the fourth terminal pin and the fifth terminal pin by a wiring pattern on a printed circuit board. (5) a clearance in a height direction exists between an attachment position of the first bobbin to the first leg portion and an attachment position of the second bobbin to the second leg portion, An inductor device according to any one of (1) to (3), assembled so that the first bobbin and the second bobbin are displaced in the same direction and pressed against one of the first core and the second core. (6) The inductor device according to any one of (1) to (3), wherein the first bobbin and the second bobbin are mounted so that their longitudinal directions are perpendicular to a printed circuit board. [Explanation of symbols]

[0061] Q1, Q2, Q3, Q4...switching elements, 10...control circuit, Lr1,Lr2...Resonance reactor, Cr1,Cr2...Resonance capacitance, 1, 11, 13··· Bobbin, 3, 5, 15, 17··· Core, 4a,6a,16a,16a1,16a2,18a,18a1,18a2...Common leg, 4b,4c,6b,6c,16b,16c,18b,18c...Leg, N1,N2,N3,N4...Coil

Claims

1. A first core having an E-shaped cross section and integrally having a first common leg, a first leg, and a second leg; a second core having an E-shaped cross section, the second core integrally including a second shared leg portion whose end face abuts against the first shared leg portion, a third leg portion opposed to the first leg portion across a first gap, and a fourth leg portion opposed to the second leg portion across a second gap having a width equal to the first gap; a first bobbin inserted into the first leg and the third leg; a first coil and a second coil wound separately on the first bobbin; a second bobbin inserted into the second leg portion and the fourth leg portion and having substantially the same shape as the first bobbin; a third coil and a fourth coil wound separately on the second bobbin; Equipped with two coils at corresponding positions in an X-shape when the first coil, the second coil, the third coil, and the fourth coil are viewed from the front are connected in series; a clearance in a height direction exists between an attachment position of the first bobbin to the first leg portion and the third leg portion, and between an attachment position of the second bobbin to the second leg portion and the fourth leg portion, An inductor device assembled such that the first bobbin and the second bobbin are displaced in the same direction and brought into contact with one of the first core and the second core.

2. the first bobbin and the second bobbin each have a first separator, a second separator, and a third separator protruding from both ends and a center portion of a cylindrical body, respectively; the first coil is wound between the first separator and the second separator of the first bobbin; the second coil is wound between the second separator and the third separator of the first bobbin; the third coil is wound between the first separator and the second separator of the second bobbin; the fourth coil is wound between the second separator and the third separator of the second bobbin; 2. The inductor device according to claim 1, wherein the inductances formed by the first coil to the fourth coil are approximately equal to each other.

3. 2. The inductor device according to claim 1, wherein the first coil and the fourth coil are connected in series, and the second coil and the third coil are connected in series.

4. first and second terminal pins connected to both ends of the first coil, and third and fourth terminal pins connected to both ends of the second coil, are provided on a lower portion of the first bobbin; fifth and sixth terminal pins connected to both ends of the third coil, and seventh and eighth terminal pins connected to both ends of the fourth coil, are provided on a lower portion of the second bobbin; the first coil and the fourth coil are connected in series by connecting the second terminal pin and the seventh terminal pin through a wiring pattern on a printed circuit board; 4. The inductor device according to claim 3, wherein the second coil and the third coil are connected in series by connecting the fourth terminal pin and the fifth terminal pin by a wiring pattern on a printed circuit board.

5. 2. The inductor device according to claim 1, wherein the first bobbin and the second bobbin are mounted so that their longitudinal directions are perpendicular to a printed circuit board.

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