Transformer-integrated reactor unit

Abstract

To provide a transformer-integrated reactor unit that can suppress increases in the size and number of parts of the target system. [Solution] The transformer-integrated reactor unit includes first and second cores having a back and two legs extending spaced apart from the back; a third core integrated with the first and second cores such that one end abuts against the end faces of the two legs of the first core and the other end abuts against the end faces of the two legs of the second core; two first reactor coils wound around the corresponding legs of the first core and connected in series; two second reactor coils wound around the corresponding legs of the second core and connected in series; a first transformer coil wound around the back of the first core and the third core through the space between the two legs of the second core; and a second transformer coil wound around the back of the second core and the third core through the space between the two legs of the first core.

Description

Technical Field

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[0001] The present disclosure relates to a transformer-integrated reactor unit. <000​​​​​​​​​​​​​​​​​​​​​​​​​​​​In a system containing multiple boost chopper circuits and multiple isolated transformers, components are needed to connect the core, coil, and input / output terminals for each reactor, as well as for each transformer, leading to an increase in the overall size and number of components of the system.

[0005] Therefore, the primary purpose of this disclosure is to provide a transformer-integrated reactor unit that can suppress increases in the size and number of components of the system to which it is applied. [Means for solving the problem]

[0006] The transformer-integrated reactor unit of the present disclosure includes first and second cores, each having a back and two legs extending spaced apart from the back; a third core integrated with the first and second cores such that one end abuts against the end faces of the two legs of the first core and the other end abuts against the end faces of the two legs of the second core; two first reactor coils wound around the corresponding legs of the first core and connected in series; two second reactor coils wound around the corresponding legs of the second core and connected in series; a first transformer coil wound around the back of the first core and the third core through the two legs of the second core; and a second transformer coil wound around the back of the second core and the third core through the two legs of the first core.

[0007] In the transformer-integrated reactor unit of this disclosure, the first reactor coil, together with either or both of the first and second transformer coils which serve as output windings, constitutes an isolated transformer, and the second reactor coil, together with either or both of the first and second transformer coils which serve as output windings, constitutes an isolated transformer. That is, the first and second reactor coils are used as input windings for both the isolated transformer including the first transformer coil and the isolated transformer including the second transformer coil. Furthermore, the first core is shared by the first reactor coil and the first transformer coil, the second core is shared by the second reactor coil and the second transformer coil, and the third core is shared by the first and second transformer coils. This makes it possible to suppress an increase in the size of the integrated first, second, and third cores. As a result, the transformer-integrated reactor unit of this disclosure makes it possible to effectively suppress an increase in the size and number of components of the system to which the transformer-integrated reactor unit is applied.

[0008] Furthermore, the first reactor coil may constitute a first buck-boost converter together with a first switching element and a first rectifier element, the second reactor coil may constitute a second buck-boost converter together with a second switching element and a second rectifier element, the first transformer coil may constitute a first DC / DC converter together with a first bridge circuit, and the second transformer coil may constitute a second DC / DC converter together with a second bridge circuit.

[0009] Such a transformer-integrated reactor unit makes it possible to effectively suppress increases in the size and number of components of the system including the first and second step-up / step-up converters and the first and second DC / DC converters. Furthermore, when both the first and second step-up / step-up converters are operating, by applying voltages to the first and second reactor coils such that the direction of the magnetic flux formed by the first reactor coil and passing through the third core is the same as the direction of the magnetic flux formed by the second reactor coil and passing through the third core, it is possible to suppress an increase in the number of turns of the first and second transformer coils while transforming the voltage applied to the first reactor coil by a first DC / DC converter including an isolated transformer composed of the first reactor coil and the first transformer coil, and transforming the voltage applied to the second reactor coil by a second DC / DC converter including an isolated transformer composed of the second reactor coil and the second transformer coil. Furthermore, when either the first or second step-up / step-down converter is operating, the voltage applied to one of the first or second reactor coils is transformed by a first DC / DC converter including an isolated transformer composed of one of the first or second reactor coils and a first transformer coil, and the voltage applied to one of the first or second reactor coils is transformed by a second DC / DC converter including an isolated transformer composed of one of the first or second reactor coils and a second transformer coil.

[0010] Furthermore, the carrier frequency in the first buck-boost converter and the carrier frequency in the second buck-boost converter may be the same, and the carrier frequencies in the first and second DC / DC converters may be synchronized with the carrier frequencies in the first and second buck-boost converters. This makes it possible to ensure good magnetic flux fluctuations in the third core and to use these magnetic flux fluctuations to ensure good output for the transformer including the first transformer coil and the transformer including the second transformer coil.

[0011] Furthermore, the sum of the volume of the back portion of the first core and the volume of the back portion of the second core is preferably at least 1 and at least 1.2 times the volume of the third core. This makes it possible to suppress the increase in the size of the first and second cores, and by extension the first to third cores that are integrated together, while suppressing the decrease in inductance of the isolated transformer due to magnetic saturation.

[0012] Furthermore, the first and second cores may be U-cores, and the third core may be an I-core. However, the first and second cores may also be E-cores, and the transformer-integrated reactor unit may each contain three first and second reactor coils. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing a vehicle including the transformer-integrated reactor unit of this disclosure. [Figure 2] This is a perspective view showing the transformer-integrated reactor unit of this disclosure. [Figure 3] This is a plan view showing the transformer-integrated reactor unit of the present disclosure. [Modes for carrying out the invention]

[0014] Next, with reference to the drawings, embodiments for carrying out the invention of this disclosure will be described.

[0015] Figure 1 is a schematic diagram showing a vehicle 1 including the transformer-integrated reactor unit 10 of the present disclosure. The vehicle 1 shown in the figure is a battery electric vehicle (BEV) including a motor generator MG and a high-voltage battery (energy storage device) 2. In addition to the motor generator MG and the high-voltage battery 2, the vehicle 1 includes first and second low-voltage batteries (second energy storage devices) 21, 22 having a lower voltage than the high-voltage battery 2, a positive-side system main relay SMRB and a negative-side system main relay SMRG, and a power control unit (hereinafter referred to as "PCU") 3 that exchanges power with the high-voltage battery 2 to drive the motor generator MG.

[0016] The motor-generator MG is a synchronous generator-motor (three-phase AC motor) and is connected to the output shaft, which is connected to the left and right wheels (drive wheels) W via a differential gear DF ​​and drive shaft DS, through a reduction mechanism (not shown). The motor-generator MG is driven by power from the high-voltage battery 2 and outputs drive torque to the output shaft. In addition, the motor-generator MG outputs regenerative braking torque to the output shaft when the vehicle 1 is braked.

[0017] The high-voltage battery 2 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery having a rated output voltage of 200 to 800V. The positive terminal of the high-voltage battery 2 is connected to the positive-side power line PL via the positive-side system main relay SMRB, and the negative terminal of the high-voltage battery 2 is connected to the negative-side power line NL via the negative-side system main relay SMRG. In this embodiment, the positive-side system main relay SMRB and the negative-side system main relay SMRG are normally open contact-type (mechanical) relays including a coil, a movable contact, and a fixed contact. However, the positive-side system main relay SMRB and the negative-side system main relay SMRG may be contact-type hybrid relays or semiconductor relays without a coil. The first and second low-voltage batteries (auxiliary batteries) 21 and 22 are, for example, lead-acid batteries having a rated output voltage of about 12-14V, and are connected to a plurality of auxiliary devices (low-voltage auxiliary devices) via low-voltage power lines (not shown).

[0018] The PCU3 includes an inverter 30, first and second buck-boost converters 31, 32, a filter capacitor (first capacitor) 33, a smoothing capacitor (second capacitor) 34, and first and second DC / DC converters (voltage converters) 35, 36. The inverter 30 includes six transistors (e.g., insulated-gate bipolar transistors (IGBTs)) and six diodes (not shown) connected in parallel in the opposite direction to each transistor.

[0019] The first and second buck-boost converters 31 and 32 can boost the power from the high-voltage battery 2 and step down the voltage from the motor generator MG side (inverter 30 side), respectively. As shown in Figure 1, the first buck-boost converter 31 includes two transistors (e.g., insulated-gate bipolar transistors) Tra1 and Trb1 as first switching elements, two diodes Da1 and Db1 as first rectifier elements connected in parallel in the opposite direction to each transistor Tra1 and Trb1, and a first reactor L1 included in the transformer-integrated reactor unit 10. The second buck-boost converter 32 includes two transistors (e.g., insulated-gate bipolar transistors) Tra2 and Trb2 as second switching elements, two diodes Da2 and Db2 as second rectifier elements connected in parallel in the opposite direction to each transistor Tra2 and Trb2, and a second reactor L2 included in the transformer-integrated reactor unit 10.

[0020] The positive terminal of the filter capacitor 33 is electrically connected to the positive-side power line PL (one end of the first and second reactors L1 and L2) between the positive-side system main relay SMRB and the first and second buck-boost converters 31 and 32. The negative terminal of the filter capacitor 33 is electrically connected to the negative-side power line NL between the negative-side system main relay SMRG and the first and second buck-boost converters 31 and 32. As a result, the filter capacitor 33 smooths the voltage on the high-voltage battery 2 side of the first and second buck-boost converters 31 and 32. The positive terminal of the smoothing capacitor 34 is electrically connected to the high-voltage power line HPL between the first and second buck-boost converters 31 and 32 and the inverter 30. The negative terminal of the smoothing capacitor 34 is electrically connected to the negative-side power line NL between the first and second buck-boost converters 31 and 32 and the inverter 30. As a result, the smoothing capacitor 34 smooths the voltage on the motor generator MG side of the first and second buck-boost converters 31 and 32.

[0021] The first DC / DC converter (DDC) 35 includes a first transformer coil TC1 and a first bridge circuit BC1 included in the transformer-integrated reactor unit 10. Also, the second DC / DC converter (DDC) 36 includes a second transformer coil TC2 and a second bridge circuit BC2 included in the transformer-integrated reactor unit 10. The first and second bridge circuits BC1 and BC2 are both well-known H-bridge circuits. The first and second DC / DC converters 35 and 36 step down (transform) the power on the positive electrode side power line PL side, that is, the power on the high-voltage battery 2 and PCU3 side, and supply it to the first or second low-voltage battery 21 and 22 on the low-voltage power line side and various auxiliary machines.

[0022] FIG. 2 is a perspective view showing the transformer-integrated reactor unit 10, and FIG. 3 is a plan view showing the transformer-integrated reactor unit 10. As shown in these drawings, the transformer-integrated reactor unit 10 includes, in addition to the first and second transformer coils TC1 and TC2, a first core 11, a second core 12, a third core 13, two first reactor coils LC1 constituting the first reactor L1, and two second reactor coils LC2 constituting the second reactor L2.

[0023] The first core 11 is a substantially U-shaped (substantially C-shaped) U-core formed of a soft magnetic material such as iron, silicon, permalloy, or ferrite, and has a substantially rectangular parallelepiped-shaped back portion 110 and two leg portions 115 of the same length extending in parallel from both ends of the back portion 110 at an interval. The second core 12 is also a substantially U-shaped (substantially C-shaped) U-core formed of a soft magnetic material such as iron, silicon, permalloy, or ferrite, and has a substantially rectangular parallelepiped-shaped back portion 120 and two leg portions 125 of the same length extending in parallel from both ends of the back portion 120 at an interval. The third core 13 is a substantially rectangular parallelepiped-shaped I-core formed of a soft magnetic material such as silicon, permalloy, or ferrite.

[0024] The third core 13 is integrated with the first and second cores 11 and 12 such that one end (one side) abuts against the end faces of the two legs 115 of the first core 11, and the other end (the other side opposite to the one side) abuts against the end faces of the two legs 125 of the second core 12. In this embodiment, the third core 13 is joined to the end faces of the two legs 115 of the first core 11 and the two legs 125 of the second core 12, for example, via an adhesive. This allows the first to third cores 11, 12, and 13 to be integrated to have a roughly figure-eight planar shape as shown in Figure 3, making it easy to form the core of the transformer-integrated reactor unit 10. Furthermore, in this embodiment, the sum of the volume V1 of the back portion 110 of the first core 11 and the volume V2 of the back portion 120 of the second core 12 (V1 + V2) is set to be at least 1 times and at least 1.2 times the volume V3 of the third core 13 (V3 ≤ V1 + V2 ≤ 1.2 × V3).

[0025] As shown in Figures 2 and 3, the two first reactor coils LC1 are each wound around the corresponding legs 115 of the first core 11 and connected in series, forming the first reactor L1 of the first buck-boost converter 31 together with the first core 11. Furthermore, the two second reactor coils LC2 are each wound around the corresponding legs 125 of the second core 12 and connected in series, forming the second reactor L2 of the second buck-boost converter 32 together with the second core 12. The number of turns of the first and second reactor coils LC1 and LC2 is determined according to the boosted voltage required by the first and second buck-boost converters 31 and 32. In addition, the first transformer coil TC1 is wound around the back 110 of the first core 11 and the third core 13 through the space defined between the two legs 125 of the second core 12, forming the first DC / DC converter 35 together with the first bridge circuit BC1. Furthermore, the second transformer coil TC2 is wound around the back portion 120 of the second core 12 and the third core 13 through the space defined between the two legs 115 of the first core 11, and together with the second bridge circuit BC2, constitutes the second DC / DC converter 36.

[0026] In the transformer-integrated reactor unit 10 configured as described above, the two first reactor coils LC1, together with transistors Tra1 and Trb1 and diodes Da1 and Db1, constitute the first buck-boost converter 31, and together with either or both of the first and second transformer coils TC1 and TC2, which form the output windings, constitute an isolated transformer. Furthermore, the two second reactor coils LC2, together with transistors Tra2 and Trb2 and diodes Da2 and Db2, constitute the second buck-boost converter 32, and together with either or both of the first and second transformer coils TC1 and TC2, which form the output windings, constitute an isolated transformer.

[0027] In vehicle 1, when both the first and second step-up / step-down converters 31 and 32 are operating, voltage from the high-voltage battery 2, etc., is applied to the first and second reactor coils LC1 and LC2 such that the direction of the DC magnetic flux formed by the two first reactor coils LC1 and passing through the third core 13 (see the dashed line in Figure 3) and the direction of the DC magnetic flux formed by the two second reactor coils LC2 and passing through the third core 13 (see the double dashed line in the figure) are the same. This makes it possible to reduce the voltage applied to the two first reactor coils LC1 by the first DC / DC converter 35, which includes an isolated transformer composed of the two first reactor coils LC1 and the first transformer coil TC1, and supply it to the first low-voltage battery 21 and the corresponding auxiliary equipment, while suppressing an increase in the number of turns of the first and second transformer coils TC1 and TC2. Furthermore, when both the first and second step-up / step-down converters 31 and 32 are operating, the voltage applied to the two second reactor coils LC2 can be stepped down by the second DC / DC converter 36, which includes an isolated transformer composed of the two second reactor coils LC2 and the second transformer coil TC2, and supplied to the second low-voltage battery 22 and the corresponding auxiliary equipment.

[0028] Furthermore, when only one of the first and second step-up / step-down converters 31 or 32 is operating while the vehicle 1 is in motion, the voltage applied from the high-voltage battery 2 or the like to one of the first and second reactor coils LC1 or LC2 can be stepped down by the first DC / DC converter 35, which includes an isolated transformer composed of one of the first and second reactor coils LC1 or LC2 and the first transformer coil TC1, and supplied to the first low-voltage battery 21 or the corresponding auxiliary equipment. Moreover, when either the first or second step-up / step-down converters 31 or 32 is operating, the voltage applied from the high-voltage battery 2 or the like to one of the first and second reactor coils LC1 or LC2 can be stepped down by the second DC / DC converter 36, which includes an isolated transformer composed of one of the first and second reactor coils LC1 or LC2 and the second transformer coil TC2, and supplied to the second low-voltage battery 22 or the corresponding auxiliary equipment.

[0029] As described above, in the transformer-integrated reactor unit 10, the first reactor coil LC1 constituting the first reactor L1 of the first step-up converter 31 and the second reactor coil LC2 constituting the second reactor L2 of the second step-up converter 32 are used as input windings for an isolated transformer including the first transformer coil TC1 and an isolated transformer including the second transformer coil TC2. Furthermore, in the transformer-integrated reactor unit 10, the first core 11 is shared by the first reactor coil LC1 and the first transformer coil TC1, the second core 12 is shared by the second reactor coil LC2 and the second transformer coil TC2, and the third core 13 is shared by the first and second transformer coils TC1 and TC2. This makes it possible to suppress an increase in the size of the integrated first to third cores 11, 12, and 13. As a result, the transformer-integrated reactor unit 10 makes it possible to effectively suppress increases in size and the number of components of the PCU 3, which is the system to which the transformer-integrated reactor unit 10 is applied, namely the first and second step-up / step-down converters 31, 32 and the first and second DC / DC converters 35, 36.

[0030] Furthermore, in the above-mentioned transformer-integrated reactor unit 10, the sum of the volume V1 of the back portion 110 of the first core 11 and the volume V2 of the back portion 120 of the second core 12 is set to be at least 1 and no more than 1.2 times the volume V3 of the third core 13. This makes it possible to suppress the increase in size of the back portions 110 and 120 of the first and second cores 11 and 12, and consequently the integrated first to third cores 11, 12, and 13, while suppressing the decrease in inductance of the isolated transformer including the first transformer coil TC1 and the isolated transformer including the second transformer coil TC2 due to magnetic saturation.

[0031] Furthermore, when operating both the first and second buck-boost converters 31 and 32, it is preferable to make the carrier frequency of the first buck-boost converter 31 the same as the carrier frequency of the second buck-boost converter 32, and to synchronize the carrier frequencies of the first and second DC / DC converters 35 and 36 with the carrier frequencies of the first and second buck-boost converters 31 and 32. Also, when operating only one of the first and second buck-boost converters 31 and 32, it is preferable to synchronize the carrier frequencies of the first and second DC / DC converters 35 and 36 with the carrier frequency of one of the first and second buck-boost converters 31 and 32. This makes it possible to ensure good magnetic flux fluctuations in the third core 13 and to use these magnetic flux fluctuations to ensure good output of the isolated transformer including the first transformer coil TC1 and the isolated transformer including the second transformer coil TC2.

[0032] In the above-described transformer-integrated reactor unit 10, the first and second cores 11 and 12 are U-cores, but are not limited to this, and the first and second cores 11 and 12 may be E-cores having three legs. In this case, three first reactor coils LC1 may be wound around the corresponding legs of the first core 11, which is an E-core, and connected in series with each other, and three second reactor coils LC2 may be wound around the corresponding legs of the second core 12, which is an E-core, and connected in series with each other. Furthermore, the transformer-integrated reactor unit 10 may include a core integrally formed from a soft magnetic material having a roughly figure-eight planar shape as shown in Figure 3. Moreover, it goes without saying that the transformer-integrated reactor unit 10 can be applied to power supply systems other than the PCU, including the first and second step-up / step-down converters 31 and 32, and the first and second DC / DC converters 35 and 36. Furthermore, the vehicle 1 including the transformer-integrated reactor unit 10 is not limited to a battery electric vehicle (BEV), but may be a two-motor hybrid vehicle (series-parallel type) with planetary gears for power distribution, a one-motor hybrid vehicle, a series hybrid vehicle, or a parallel hybrid vehicle.

[0033] The invention disclosed herein is not limited in any way to the embodiments described above, and it goes without saying that various modifications can be made within the scope of this disclosure. Furthermore, the embodiments described above are merely one specific form of the invention described in the summary section of the invention, and do not limit the elements of the invention described in the summary section of the invention. [Industrial applicability]

[0034] The invention disclosed herein can be used in industries such as the manufacturing of transformer-integrated reactor units. [Explanation of symbols]

[0035] 1 Vehicle, 2 High-voltage battery, 3 Power control unit (PCU), 10 Transformer-integrated reactor unit, 11 First core, 110, 120 Back section, 115, 125 Leg section, 12 Second core, 13 Third core, 21 First low-voltage battery, 22 Second low-voltage battery, 30 Inverter, 31 First buck-boost converter, 32 Second buck-boost converter, 33 Filter capacitor, 34 Smoothing capacitor, 35 First DC / DC converter, 35 Second DC / DC converter, 36 Second DC / DC converter, BC1 First bridge circuit, BC2 Second bridge circuit, L1 First reactor, L2 Second reactor, LC1 First reactor coil, LC2 Second reactor coil, TC1 First transformer coil, TC2 Second transformer coil.

Claims

1. A first and second core, each having a back portion and two legs extending from the back portion at a distance from it, A third core is integrated with the first and second cores such that one end abuts against the end faces of the two legs of the first core and the other end abuts against the end faces of the two legs of the second core, Two first reactor coils, each wound around the corresponding leg of the first core and connected in series, Two second reactor coils, each wound around the corresponding leg of the second core and connected in series, A first transformer coil is wound around the back of the first core and the third core, passing between the two legs of the second core, A second transformer coil is wound around the back of the second core and the third core, passing between the two legs of the first core, A transformer-integrated reactor unit equipped with [a specific feature / feature].

2. In the transformer-integrated reactor unit according to claim 1, The first reactor coil, together with the first switching element and the first rectifier element, constitutes a first buck-boost converter. The second reactor coil, together with the second switching element and the second rectifier element, constitutes a second buck-boost converter. The first transformer coil, together with the first bridge circuit, constitutes the first DC / DC converter. The second transformer coil, together with the second bridge circuit, constitutes a transformer-integrated reactor unit that forms the second DC / DC converter.

3. In the transformer-integrated reactor unit according to claim 2, The carrier frequency in the first buck-boost converter and the carrier frequency in the second buck-boost converter are the same. A transformer-integrated reactor unit in which the carrier frequencies in the first and second DC / DC converters are synchronized with the carrier frequencies in the first and second step-up / step-down converters.

4. In the transformer-integrated reactor unit according to claim 1 or 2, A transformer-integrated reactor unit in which the sum of the volume of the back portion of the first core and the volume of the back portion of the second core is 1 or more and 1.2 times or less the volume of the third core.

5. In the transformer-integrated reactor unit according to claim 1 or 2, A transformer-integrated reactor unit in which the first and second cores are U-cores and the third core is an I-core.

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