Voltage conversion device

Abstract

To provide a technique capable of efficiently converting voltage over a wide range of transformation ratios.SOLUTION: A voltage conversion device includes a first DC-DC converter and a second DC-DC converter. The first DC-DC converter is connected to a power supply and a storage battery, and converts voltage input from the power supply and outputs it to the storage battery. The second DC-DC converter is connected to the power supply and the storage battery in parallel with the first DC-DC converter, and converts voltage input from the power supply and outputs it to the storage battery. The first DC-DC converter and the second DC-DC converter are each an isolated DC-DC converter equipped with a transformer. A turn ratio of the transformer in the first DC-DC converter is different from a turn ratio of the transformer in the second DC-DC converter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a voltage conversion device. [Background technology]

[0002] Patent Document 1 discloses a voltage conversion device that converts and outputs a voltage input from a power supply. The voltage conversion device of Patent Document 1 includes a first converter connected to the power supply and a second converter connected to the power supply in parallel with the first converter. The first converter and the second converter are each an isolated converter equipped with a transformer, and convert the voltage input from the power supply and output it to a load. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-225126 Summary of the Invention [Problem to be solved by the invention]

[0004] The voltage conversion device of Patent Document 1 aims to improve the life and reliability of the entire device by equally distributing the output current to the load among the converters, but there is room for further improvement.This specification provides a technology that can efficiently convert voltage over a wide range of transformation ratios. [Means for solving the problem]

[0005] A first aspect of the present technology discloses a voltage conversion device that converts a voltage input from a power supply and outputs the converted voltage to a storage battery. The voltage conversion device includes: a first DC-DC converter connected to the power supply and the storage battery and converts the voltage input from the power supply and outputs the converted voltage to the storage battery; and a second DC-DC converter connected to the power supply and the storage battery in parallel with the first DC-DC converter and converts the voltage input from the power supply and outputs the converted voltage to the storage battery. The first DC-DC converter and the second DC-DC converter may each be an isolated DC-DC converter including a transformer. A turns ratio of the transformer in the first DC-DC converter may be different from a turns ratio of the transformer in the second DC-DC converter.

[0006] With this configuration, the first DC-DC converter and the second DC-DC converter have different transformer turns ratios, so the transformation ratio at which the first DC-DC converter can efficiently convert voltage differs from the transformation ratio at which the second DC-DC converter can efficiently convert voltage. Therefore, by using the first DC-DC converter and the second DC-DC converter, it is possible to efficiently convert voltage over a wide range of transformation ratios.

[0007] In a second aspect, in the first aspect, the storage battery may include a first storage battery and a second storage battery. The first DC-DC converter and the second DC-DC converter may be connected in parallel to the first storage battery and also connected in parallel to the second storage battery. The first DC-DC converter may be connected to the second storage battery via a relay. The second DC-DC converter may be connected to the first storage battery via a relay.

[0008] With this configuration, by disconnecting the relay in the event of an abnormality, the connection between the first DC-DC converter and the second storage battery can be cut off while maintaining the connection between the first DC-DC converter and the first storage battery. Similarly, the connection between the second DC-DC converter and the first storage battery can be cut off while maintaining the connection between the second DC-DC converter and the second storage battery. This ensures a redundant configuration.

[0009] In a third aspect, the above-mentioned first or second aspect may be mounted on an electric vehicle.

[0010] This configuration allows efficient voltage conversion over a wide range of transformation ratios in an electric vehicle. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a circuit diagram of a DC-DC converter according to a first embodiment. [Figure 2] FIG. 10 is a circuit diagram of a DC-DC converter according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Example 1 A voltage conversion device 2 of Example 1 will be described with reference to the drawings. As shown in Fig. 1, the voltage conversion device 2 of Example 1 is connected to a power source 50 and a first storage battery 60. The input side (primary side) of the voltage conversion device 2 is connected to the power source 50, and the output side (secondary side) is connected to the first storage battery 60. The voltage conversion device 2 is mounted on, for example, an electrically powered vehicle (for example, an electric vehicle or a hybrid vehicle).

[0013] The power supply 50 is, for example, a battery for propelling the electric vehicle. The power supply 50 may be a primary battery or a secondary battery. The first storage battery 60 is, for example, a battery other than the battery for propelling the electric vehicle (for example, an auxiliary battery).

[0014] The voltage conversion device 2 includes a first DC-DC converter 10 connected to a power source 50 and a first storage battery 60, and a second DC-DC converter 20 connected in parallel to the first DC-DC converter 10 to the power source 50 and the first storage battery 60.

[0015] The first DC-DC converter 10 includes a primary side circuit 14, a secondary side circuit 16, and a transformer 12 arranged between the primary side circuit 14 and the secondary side circuit 16. The first DC-DC converter 10 is an isolated converter in which the primary side circuit 14 and the secondary side circuit 16 are isolated via the transformer 12. The first DC-DC converter 10 converts (steps down or steps up) the voltage input from the power source 50 and outputs it to the first storage battery 60 through cooperation between the primary side circuit 14 and the secondary side circuit 16. The first DC-DC converter 10 transmits power from the primary side circuit 14 to the secondary side circuit 16 via the transformer 12.

[0016] The primary side circuit 14 is connected to the power supply 50. The primary side circuit 14 includes a plurality of switching elements (not shown). The primary side circuit 14, for example, configures a bridge circuit using the plurality of switching elements. Each switching element includes a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). The primary side circuit 14 transmits power supplied from the power supply 50 to the secondary side circuit 16 by turning the plurality of switching elements on and off.

[0017] The secondary side circuit 16 is connected to the first storage battery 60. The secondary side circuit 16 includes a plurality of switching elements (not shown). The secondary side circuit 16, for example, configures a bridge circuit using the plurality of switching elements. Each switching element includes a transistor such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The secondary side circuit 16 supplies power transmitted from the primary side circuit 14 to the first storage battery 60 by turning the plurality of switching elements on and off. The first DC-DC converter 10 can change the transformation ratio (step-down ratio or step-up ratio) by changing the duty ratio of the driving times of the plurality of switching elements in the primary side circuit 14 and the secondary side circuit 16.

[0018] The transformer 12 of the first DC-DC converter 10 includes a primary coil 122 and a secondary coil 124. The primary coil 122 and the secondary coil 124 are spaced apart and insulated from each other. The number of turns of the primary coil 122 is different from the number of turns of the secondary coil 124.

[0019] The second DC-DC converter 20 includes a primary side circuit 24, a secondary side circuit 26, and a transformer 22 arranged between the primary side circuit 24 and the secondary side circuit 26. The second DC-DC converter 20 is an isolated converter in which the primary side circuit 24 and the secondary side circuit 26 are insulated from each other via the transformer 22. The second DC-DC converter 20 converts (steps down or steps up) the voltage input from the power source 50 and outputs it to the first storage battery 60, with the primary side circuit 24 and the secondary side circuit 26 working together. The second DC-DC converter 20 transmits power from the primary side circuit 24 to the secondary side circuit 26 via the transformer 22.

[0020] The primary side circuit 24 is connected to the power supply 50. The primary side circuit 24 includes a plurality of switching elements (not shown). The primary side circuit 24, for example, configures a bridge circuit using the plurality of switching elements. Each switching element includes a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). The primary side circuit 24 transmits power supplied from the power supply 50 to the secondary side circuit 26 by turning the plurality of switching elements on and off.

[0021] The secondary side circuit 26 is connected to the first storage battery 60. The secondary side circuit 26 includes a plurality of switching elements (not shown). The secondary side circuit 26, for example, configures a bridge circuit using the plurality of switching elements. Each switching element includes a transistor such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The secondary side circuit 26 supplies power transmitted from the primary side circuit 24 to the first storage battery 60 by turning the plurality of switching elements on and off. The second DC-DC converter 20 can change the transformation ratio (step-down ratio or step-up ratio) by changing the duty ratio of the driving times of the plurality of switching elements in the primary side circuit 24 and the secondary side circuit 26.

[0022] The transformer 22 of the second DC-DC converter 20 includes a primary coil 222 and a secondary coil 224. The primary coil 222 and the secondary coil 224 are spaced apart and insulated from each other. The number of turns of the primary coil 222 is different from the number of turns of the secondary coil 224.

[0023] In the voltage conversion device 2 described above, the turns ratio of the transformer 12 of the first DC-DC converter 10 is different from the turns ratio of the transformer 22 of the second DC-DC converter 20. For example, the turns ratio of the transformer 12 of the first DC-DC converter 10 is larger than the turns ratio of the transformer 22 of the second DC-DC converter 20. In a modified example, the turns ratio of the transformer 12 of the first DC-DC converter 10 may be smaller than the turns ratio of the transformer 22 of the second DC-DC converter 20. The turns ratio of each transformer 12, 22 is the ratio of the number of turns of the winding of the primary side coil 122, 222 of each transformer 12, 22 to the number of turns of the winding of the secondary side coil 124, 224 (i.e., the number of turns of the winding of the primary side coil 122, 222 / the number of turns of the winding of the secondary side coil 124, 224).

[0024] (effect) The voltage conversion device 2 of the embodiment has been described above. As is clear from the above description, the voltage conversion device 2 includes a first DC-DC converter 10 and a second DC-DC converter 20 connected in parallel. The first DC-DC converter 10 and the second DC-DC converter 20 are isolated DC-DC converters including transformers 12 and 22, respectively. The turns ratio of the transformer 12 in the first DC-DC converter 10 is different from the turns ratio of the transformer 22 in the second DC-DC converter 20.

[0025] With this configuration, the turns ratios of the transformers 12, 22 differ between the first DC-DC converter 10 and the second DC-DC converter 20, and therefore the transformation ratio at which the first DC-DC converter 10 can efficiently convert voltage differs from the transformation ratio at which the second DC-DC converter 20 can efficiently convert voltage. Therefore, by using the first DC-DC converter 10 and the second DC-DC converter 20, it is possible to efficiently convert voltage over a wide range of transformation ratios. It is also possible to improve the efficiency of the auxiliary battery of the electric vehicle and prevent failures.

[0026] Although the first embodiment has been described above, the configuration of the voltage conversion device 2 is not limited to the above embodiment. In the following description, detailed description of the same configuration as that described above may be omitted.

[0027] Example 2 2, the voltage converter 2 of the second embodiment is connected to a first storage battery 60 and a second storage battery 62. The second storage battery 62 is, for example, a battery other than the battery for propelling the electric vehicle (for example, an auxiliary battery). The voltage converter 2 also includes a relay 30.

[0028] The first DC-DC converter 10 and the second DC-DC converter 20 are connected in parallel to a first storage battery 60. The first DC-DC converter 10 and the second DC-DC converter 20 are connected in parallel to a second storage battery 62.

[0029] The relay 30 is disposed between the first DC-DC converter 10 and the second storage battery 62. The first DC-DC converter 10 is connected to the second storage battery 62 via the relay 30. The relay 30 is also disposed between the second DC-DC converter 20 and the first storage battery 60. The second DC-DC converter 20 is connected to the first storage battery 60 via the relay 30.

[0030] When the relay 30 is on, the first DC-DC converter 10 and the second storage battery 62 are connected, and the second DC-DC converter 20 and the first storage battery 60 are connected. When the relay 30 is off, the connection between the first DC-DC converter 10 and the second storage battery 62 is cut off, and the connection between the second DC-DC converter 20 and the first storage battery 60 is cut off.

[0031] According to the above configuration, by disconnecting the relay 30 in the event of an abnormality, it is possible to cut off the connection between the first DC-DC converter 10 and the second storage battery 62 while maintaining the connection between the first DC-DC converter 10 and the first storage battery 60. Similarly, it is possible to cut off the connection between the second DC-DC converter 20 and the first storage battery 60 while maintaining the connection between the second DC-DC converter 20 and the second storage battery 62. This ensures a redundant configuration.

[0032] (Variation) (1) In the second embodiment, the first DC-DC converter 10 and the second storage battery 62 are connected via one relay 30, and the second DC-DC converter 20 and the first storage battery 60 are connected via one relay 30. However, this configuration is not limiting. In a modified example, the first DC-DC converter 10 may be connected to the second storage battery 62 via a first relay (not shown), and the second DC-DC converter 20 may be connected to the first storage battery 60 via a second relay (not shown) different from the first relay.

[0033] (2) The voltage conversion device 2 is applicable not only to electric vehicles but also to other configurations that consume power. For example, the voltage conversion device 2 is applicable to servers, aircraft, electrical appliances, and the like.

[0034] 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 itself has technical utility. [Explanation of symbols]

[0035] 2: voltage conversion device, 10: first DC-DC converter, 12: transformer, 20: second DC-DC converter, 22: transformer, 30: relay, 50: power supply, 60: first storage battery, 62: second storage battery

Claims

1. A voltage conversion device that converts a voltage input from a power source and outputs the converted voltage to a storage battery, a first DC-DC converter connected to the power supply and the storage battery, converting a voltage input from the power supply and outputting the converted voltage to the storage battery; a second DC-DC converter connected in parallel to the first DC-DC converter to the power supply and the storage battery, converting a voltage input from the power supply and outputting the converted voltage to the storage battery; the first DC-DC converter and the second DC-DC converter are each an isolated DC-DC converter including a transformer; A voltage conversion device, wherein a turns ratio of the transformer in the first DC-DC converter is different from a turns ratio of the transformer in the second DC-DC converter.

2. 2. The voltage conversion device according to claim 1, the storage battery includes a first storage battery and a second storage battery; the first DC-DC converter and the second DC-DC converter are connected in parallel to the first storage battery and are also connected in parallel to the second storage battery; the first DC-DC converter is connected to the second storage battery via a relay; The second DC-DC converter is connected to the first storage battery via a relay.

3. 3. The voltage conversion device according to claim 1, A voltage conversion device installed in electric vehicles.

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