Multiphase converter

Abstract

To provide a technique that can accurately measure the temperature of the core of a coupling reactor in a multiphase converter that uses the coupling reactor.SOLUTION: A multiphase converter disclosed herein includes a first / second voltage converter circuit and a magnetic coupling reactor. The first (second) voltage converter circuit includes a first (second) switching element for voltage conversion and a first (second) coil connected to the first (second) switching element. The first coil and the second coil are included in the magnetic coupling reactor. The magnetic coupling reactor includes three I-shaped cores arranged in parallel, a pair of connecting cores connecting both ends of the three I-shaped cores, and a temperature sensor. The temperature sensor is fixed to the central I-shaped core. Of the three I-shaped cores arranged side by side, a first coil is wound around the I-shaped core at one end, and a second coil is wound around the I-shaped core at the other end.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a multi-phase converter in which a plurality of voltage converter circuits are connected in parallel. [Background technology]

[0002] A multi-phase converter in which multiple voltage converter circuits are connected in parallel is known (for example, Patent Document 1). The voltage converter circuit includes a switching element for voltage conversion and a coil (reactor). In the multi-phase converter of Patent Document 1, the coils of the multiple voltage converter circuits share a core. A reactor in which the coils of the multiple voltage converter circuits are wound around one core is sometimes called a magnetically coupled reactor. The magnetically coupled reactor of Patent Document 1 includes three I cores and a connecting core that connects both ends of the three I cores, and a coil is wound around each of the three I cores. In addition, a temperature sensor is disposed between adjacent coils to measure the coil temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7030898 Summary of the Invention [Problem to be solved by the invention]

[0004] Heat from the coil is transferred to the core, but in the magnetic coupling reactor of Patent Document 1, the temperature sensor is not in contact with the core, making it impossible to accurately measure the core temperature. This specification relates to a multi-phase converter using a coupling reactor, and provides a technology that can accurately measure the core temperature of the coupling reactor. [Means for solving the problem]

[0005] The multi-phase converter disclosed in this specification includes a first / second voltage converter circuit and a magnetic coupling reactor. The first (second) voltage converter circuit includes a first (second) switching element for voltage conversion and a first (second) coil connected to the first (second) switching element. The first coil and the second coil are included in the magnetic coupling reactor. The magnetic coupling reactor includes three I-shaped cores arranged in parallel, a pair of connecting cores connecting both ends of the three I-shaped cores, and a temperature sensor. The temperature sensor is fixed to the central I-shaped core. Of the three I-shaped cores arranged side by side, a first coil is wound around the I-shaped core at one end, and a second coil is wound around the I-shaped core at the other end. Since the temperature sensor is fixed directly to the cores, it is possible to accurately measure the core temperature.

[0006] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a circuit diagram of a multi-phase converter according to an embodiment. [Figure 2] FIG. 2 is a plan view of the reactor. [Figure 3] 3 is a cross-sectional view of the reactor taken along line III-III in FIG. 2. [Figure 4] FIG. 10 is a plan view of a reactor according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] A multi-phase converter 2 according to an embodiment will be described with reference to the drawings. Fig. 1 shows a circuit diagram of the multi-phase converter 2. The multi-phase converter 2 includes a first voltage converter circuit 10 and a second voltage converter circuit 20. A first coil 12 of the first voltage converter circuit 10 and a second coil 22 of the second voltage converter circuit 20 are included in a magnetic coupling reactor 30.

[0009] The multi-phase converter 2 has input terminals 2ap and 2an and output terminals 2bp and 2bn. The multi-phase converter 2 can boost the voltage applied to the input terminals 2ap and 2an and output it from the output terminals 2bp and 2bn. Two voltage converter circuits 10 and 20 are connected in parallel between the input terminals 2ap and 2an and the output terminals 2bp and 2bn. The negative terminal 2an of the input terminal and the negative terminal 2bn of the output terminal are connected to ground G. By connecting the two voltage converter circuits 10 and 20 in parallel, the multi-phase converter 2 can handle large amounts of power.

[0010] The first voltage converter circuit 10 includes a first switching element 11, a first coil 12 connected in series to the first switching element 11, and diodes 13 and 14. For ease of explanation, one end of the first coil 12 is referred to as terminal A, and the other end is referred to as terminal B. Terminal A of the first coil 12 is connected to the first switching element 11, and terminal B of the first coil 12 is connected to the positive electrode 2ap of the input terminal. The low-potential end of the first switching element 11 is connected to ground G. A diode 14 is connected in antiparallel to the first switching element 11. A diode 13 is connected between terminal A of the first coil 12 and the positive electrode 2bp of the output terminal. The anode of the diode 13 is connected to terminal A of the first coil 12, and the cathode is connected to the positive electrode 2bp of the output terminal. The diode 13 prevents reverse current flow from the positive electrode 2bp to the first coil 12 or the first switching element 11. The first switching element 11 is controlled by a controller 6. When the controller 6 appropriately turns on and off the first switching element 11, the voltage applied to the positive electrode 2ap of the output terminal is boosted and output from the positive electrode 2bp of the output terminal. The first switching element 11 (and the second switching element 21, which will be described later) are switching elements for voltage conversion and are sometimes called power elements.

[0011] The second voltage converter circuit 20 includes a second switching element 21, a second coil 22 connected in series to the second switching element 21, and diodes 23 and 24. The configuration of the second voltage converter circuit 20 is the same as that of the first voltage converter circuit 10, and therefore a detailed description thereof will be omitted. For ease of explanation, one end and the other end of the second coil 22 will also be referred to as end A and end B, respectively. End A of the second coil 22 is connected to the second switching element 21. When the controller 6 appropriately turns the second switching element 21 on and off, the voltage applied to the positive electrode 2ap of the output terminal is boosted and output from the positive electrode 2bp of the output terminal.

[0012] The multi-phase converter 2 further includes a voltage sensor 3 that measures the voltage at the input terminals 2ap and 2an, a voltage sensor 4 that measures the voltage at the output terminals 2bp and 2bn, a current sensor 15 that measures the current flowing through the first coil 12, a current sensor 25 that measures the current flowing through the second coil 22, and a capacitor 5 connected between the positive terminal 2bp and the negative terminal 2bn of the output terminal.

[0013] The first coil 12 and the second coil 22 are also components of a magnetic coupling reactor 30. Hereinafter, the magnetic coupling reactor 30 will be simply referred to as the reactor 30. Fig. 2 shows a plan view of the reactor 30. Fig. 3 shows a cross-sectional view of the reactor 30 taken along line III-III in Fig. 2.

[0014] In addition to the first coil 12 and the second coil 22, the reactor 30 includes three I-shaped cores 31, 32, and 33, a pair of connecting cores 34a and 34b, a temperature sensor 35, and a cooler 36. The three I-shaped cores 31, 32, and 33 are arranged in parallel, and the pair of connecting cores 34a and 34b connect the ends of the three I-shaped cores 31, 32, and 33. One connecting core 34a connects one ends of the three I-shaped cores 31, 32, and 33. The other connecting core 34b connects the other ends of the three I-shaped cores 31, 32, and 33. The I-shaped cores 31 and 33 on both sides and the pair of connecting cores 34a and 34b form a ring shape, and the central I-shaped core 32 is arranged to connect two points on the inner surface of the ring.

[0015] The first coil 12 is wound around the I-shaped core 31 at one end of the three I-shaped cores 31, 32, and 33, and the second coil 22 is wound around the I-shaped core 33 at the other end. No coil is wound around the central I-shaped core 32. A temperature sensor 35 is fixed to the central I-shaped core 32. When the two voltage converter circuits 10 and 20 operate, current flows through the first coil 12 and the second coil 22, causing these coils to generate heat. The heat from the coils is transferred to the I-shaped cores 31 and 33 on both sides and is also diffused to the other cores (the I-shaped core 32 and the pair of connecting cores 34a and 34b). Because the central I-shaped core 32 is located between the I-shaped cores 31 and 33 on both sides around which coils are wound, its temperature is raised by the heat from the coils on both sides (the first coil 12 and the second coil 22). The temperature of the central I-core 32 is closest to the average temperature of the entire core (all cores). A temperature sensor 35 is fixed to the central I-core 32. The temperature sensor 35 can accurately measure the core temperature.

[0016] A cooler 36 is also disposed below the core, and the first coil 12 and second coil 22 are in thermal contact with the cooler 36 via a heat transfer sheet 37. A gap 39 is provided between the central I-shaped core 32 and the cooler 36, so the I-shaped core 32 is not directly cooled. This structural feature also contributes to the temperature of the central I-shaped core 32 being close to the average temperature of the entire core.

[0017] The direction of current flowing through the cores will now be described. As shown in Fig. 2, the first coil 12 is wound counterclockwise around the I-shaped core 31 from end A to end B. Similarly, the second coil 22 is wound counterclockwise around the I-shaped core 33 from end A to end B. Furthermore, the A-ends of both the first coil 12 and the second coil 22 are located on the side of one connecting core 34a, and the B-ends are located on the side of the other connecting core 34b.

[0018] The A terminals of the first coil 12 and the second coil 22 are both connected to the switching elements. When the controller 6 synchronously turns on and off the first switching element 11 and the second switching element 21, current flows in the same direction (from A terminal to B terminal, or from B terminal to A terminal) through the first coil 12 and the second coil 22. The solid arrows in FIG. 2 indicate the direction of the current. When the winding directions of the first coil 12 and the second coil 22 are in the relationship described above, magnetic flux is generated in the direction of the dashed line in FIG. 2. In the pair of connecting cores 34a, 34b, the first coil 12 and the second coil 22 generate magnetic flux in opposite directions. In the central I-shaped core 32, the magnetic fluxes generated by the first coil 12 and the second coil 22 overlap.

[0019] 4 shows a plan view of a reactor 130 of a modified example. The reactor 130 includes three I-shaped cores 131, 132, and 133 and a pair of connecting cores 34a and 34b. The pair of connecting cores 34a and 34b connect the ends of the three I-shaped cores 131, 132, and 133 together. The I-shaped core 131 is divided into partial cores 131a and 131b, with a gap (Gap) between them. The I-shaped core 132 (133) is divided into partial cores 132a and 132b (133a and 133b), with a gap (Gap) between them.

[0020] Of the three I-shaped cores 131, 132, and 133 arranged in parallel, a first coil 112 is wound around the I-shaped core 131 at one end, and a second coil 122 is wound around the I-shaped core 133 at the other end. No coil is wound around the central I-shaped core 132, and a temperature sensor 35 is fixed thereto.

[0021] The first coil 112 is wound counterclockwise from end A to end B around the I-shaped core 131. Conversely, the second coil 122 is wound clockwise from end A to end B around the I-shaped core 133. Furthermore, the A-end of the first coil 112 is located on the side of one connecting core 34a, while the A-end of the second coil 122 is located on the side of the other connecting core 34b.

[0022] The A terminals of the first coil 112 and the second coil 122 are both connected to the switching elements. When the controller 6 synchronously turns on and off the first switching element 11 and the second switching element 21, current flows in the same direction (from A terminal to B terminal, or from B terminal to A terminal) through the first coil 112 and the second coil 122. The solid arrows in FIG. 4 indicate the direction of the current. When the winding directions of the first coil 112 and the second coil 122 are in the relationship described above, magnetic flux is generated in the direction of the dashed line in FIG. 4. In the pair of coupled cores 34a, 34b, the first coil 112 and the second coil 122 generate magnetic flux in opposite directions. In the central I-shaped core 132, the magnetic fluxes generated by the first coil 112 and the second coil 122 overlap.

[0023] As described above, the multi-phase converter 2 of the embodiment includes the magnetic coupling reactor 30 shared by two voltage converter circuits (the first voltage converter circuit 10 and the second voltage converter circuit 20). The magnetic coupling reactor 30 has three I-shaped cores 31, 32, and 33, with a coil wound around each of the I-shaped cores 31 and 33 on both sides, and no coil wound around the central I-shaped core 32. A temperature sensor 35 is fixed to the I-shaped core 32. The temperature sensor 35 can accurately measure the average temperature of the entire core. The magnetic coupling reactor 130 of the modified example also has similar advantages.

[0024] Here are some points to note regarding the technology described in the embodiments. The technology disclosed in this specification is also suitable for application to a multi-phase converter in which an even number of four or more voltage converter circuits are connected in parallel. In this case, the even number of voltage converter circuits are paired in pairs, and the coils of each pair of voltage converter circuits are wound around the core of a magnetic coupling reactor. For example, a multi-phase converter having 2N voltage converter circuits connected in parallel is equipped with N magnetic coupling reactors, and the coils of the pair of voltage converter circuits are wound around each magnetic coupling reactor.

[0025] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone is technically useful. [Explanation of symbols]

[0026] 2: Multi-phase converter 3, 4: Voltage sensor 5: Capacitor 6: Controller 10, 20: Voltage converter circuit 11, 21: Switching element 12, 22, 112, 122: Coil 13, 14, 23, 24: Diode 15, 25: Current sensor 30, 130: Magnetic coupling reactor 31, 32, 33, 131, 132, 133: I-shaped core 34a, 34b: Connecting core 35: Temperature sensor 36: Cooler 37: Heat transfer sheet 39: Air gap

Claims

[Claim 1] a first voltage converter circuit including a first switching element for voltage conversion and a first coil connected to the first switching element; a second voltage converter circuit connected in parallel with the first voltage converter circuit and including a second switching element for voltage conversion and a second coil connected to the second switching element; a magnetic coupling reactor including the first coil and the second coil; It is equipped with The magnetic coupling reactor is The device comprises three I-shaped cores arranged in parallel, a pair of connecting cores connecting both ends of the three I-shaped cores, and a temperature sensor fixed to the central I-shaped core, Of the three I-shaped cores arranged side by side, the first coil is wound around the I-shaped core at one end, and the second coil is wound around the I-shaped core at the other end. Multiphase converter.

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