JP2019213321A - Power control system - Google Patents

Abstract

To provide a power control system capable of reducing load on a power converter.SOLUTION: A power control system 100 comprises: an SOFC 10 for generating power of a low voltage; a high voltage battery 12 which is charged with the power generated by the SOFC 10; a first running motor 20 that receives supply of power from the high voltage battery 12; a power converter connected between the SOFC 10 and the high voltage battery 12; and a second running motor 26 that receives supply of power from the SOFC 10. The power converter includes an insulation-type power converter (FC insulation converter 14).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power control system.

  Patent document 1 arrange | positions a power converter between the fuel cell stack as an electric power generation apparatus, an external load, and a power storage device, and uses the power converter to generate a pulse current from the fuel cell stack according to the demand of the power storage device. A retrieval system is disclosed.

  In order to enable the above power generation device to be handled as a component not subject to high voltage safety requirements, the power generation device has a high step-up ratio so that the output voltage of the power generation device can be covered even below a predetermined voltage and generates power It has been proposed to apply an insulated power converter as a power converter that electrically insulates the device from the power storage device. Thereby, the layout freedom degree in the electric vehicle of the electric power generation apparatus at the time of mounting the said system in an electric vehicle improves. On the other hand, when the system is mounted on an electric vehicle, the power generation device is required to have a high output, and in response to this, the power converter is also required to have a high output. .

Japanese Patent No. 46616247

  However, it is difficult to realize a power converter having a high output in a size that can be mounted on a vehicle, and even if it can be mounted on a vehicle, it causes a problem of an increase in cost and a decrease in conversion efficiency of the power converter.

  Then, an object of this invention is to provide the power control system which reduces the burden with respect to a power converter.

  According to an aspect of the present invention, a power generation device that generates low-voltage power, a high-voltage battery that is charged with power generated by the power generation device, and a first external that is supplied with power from the high-voltage battery A load, a power converter connected between the power generation device and the high voltage battery, and a second external load that receives supply of power from the power generation device. Then, a power control system is provided in which the power conversion device includes an insulated power converter.

  If it is the said aspect, since the insulation type power converter was used as a power converter, the electric power generation apparatus with a voltage lower than a high voltage battery can be used. Therefore, even when a problem occurs in the power generation device, it is possible to reduce the risk caused by the high voltage of the power generation device.

  Insulated power converters use magnetic components, so the size increases as the current increases. However, if it is the said aspect, since the output of an electric power generation apparatus is directly supplied to a 2nd external load, without passing through a power converter, the increase in the passing current of the said insulated power converter can be avoided. Therefore, for example, even in an electric vehicle with strict layout requirements, a power converter with a large output can be installed in a size that can be mounted on a vehicle, and a range extender system that extends the cruising distance of an electric vehicle with the power supplied by the power generation device is realized can do. Furthermore, by avoiding an increase in the passing current of the insulated power converter, a loss in the insulated power converter can be avoided, and the system efficiency can be improved.

FIG. 1 is a diagram illustrating the configuration of the power control system according to the first embodiment. FIG. 2 is a diagram illustrating a high output state in the power control system of the first embodiment. FIG. 3 is a diagram illustrating a state where driving of the FC insulating converter is stopped in the power control system of the first embodiment. FIG. 4 is a diagram illustrating a state where driving of the FC insulating converter and the first travel motor is stopped in the power control system of the first embodiment. FIG. 5 is a diagram illustrating a state in which regenerative power is generated in the power control system of the first embodiment. FIG. 6 is a diagram illustrating a comparative example of the power control system of the first embodiment. FIG. 7 is a diagram illustrating the configuration of the power control system of the second embodiment. FIG. 8 is a diagram illustrating the configuration of the power control system of the third embodiment. FIG. 9 is a flowchart illustrating a control mode of the power control system of the third embodiment. FIG. 10 is a diagram showing an outline of IV curves of two SOFCs 10-1 and SOFC 10-2 having different output characteristics. FIG. 11 is a diagram illustrating the configuration of the power control system of the fourth embodiment. FIG. 12 is a flowchart illustrating a control mode of the power control system of the fourth embodiment. FIG. 13 is a diagram illustrating the configuration of the power control system of the fifth embodiment. FIG. 14 is a flowchart illustrating a control mode of the power control system according to the fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a diagram illustrating a schematic configuration of a power control system 100 according to the first embodiment.

  As shown in the figure, the power control system 100 includes a SOFC (solid oxide fuel cell) 10 as a power generator and power generated (generated) by the SOFC 10 or power supplied from the outside. A high voltage battery 12 to be charged, and an FC insulation converter 14 as a power converter disposed between the SOFC 10 and the high voltage battery 12, and the high voltage side of the FC insulation converter 14 and the high voltage battery 12 are The low voltage side of the FC insulation converter 14 and the SOFC 10 are connected to the low voltage line 22 by the high voltage line 16.

  Further, the power control system 100 includes a first traveling motor 20 as a first external load connected to the high voltage line 16 via the first motor inverter 18 and driven by power supplied from the high voltage battery 12, and a low voltage. And a second traveling motor 26 (second external load) serving as a second external load connected to the line 22 via the second motor inverter 24 and driven by electric power supplied from the SOFC 10. Here, as the second external load, in addition to the second traveling motor 26, a fuel system auxiliary device and an air system auxiliary device for driving the SOFC 10, and an auxiliary device for an electric vehicle (air conditioner, headlight, etc.) may be applied. it can.

  The SOFC 10 is configured as an SOFC stack formed by stacking cells obtained by sandwiching an electrolyte layer formed of a solid oxide such as ceramic between an anode (fuel electrode) and a cathode (air electrode). The SOFC 10 generates power by receiving the supply of fuel gas (hydrogen) to the fuel electrode and the supply of oxidizing gas (oxygen) to the air electrode.

  In the SOFC 10 in the present embodiment, for example, when the charging power of the high voltage battery 12 is insufficient for the request, the FC insulation converter 14 outputs a predetermined current (power generation) according to the required power. Further, the SOFC 10 appropriately supplies power to the second travel motor 26 based on the power request from the second travel motor 26.

  Each unit cell constituting the SOFC 10 has an output voltage of about 1.0V. Therefore, the output voltage of the SOFC 10 can be arbitrarily adjusted by appropriately adjusting the number of stacked unit cells.

  In the present embodiment, the number of stacked unit cells is adjusted so that the voltage of the SOFC 10 is as low as possible from the viewpoint of further improving safety. In particular, the number of stacked unit cells is adjusted so that the maximum output voltage of the SOFC 10 is less than 60V. The SOFC 10 may be configured as a fuel cell system that further includes a fuel system auxiliary machine and an air system auxiliary machine.

  It is necessary to supply power to a fuel system auxiliary machine (fuel pump, injector, etc.) and an air system auxiliary machine (compressor, etc.) for driving the SOFC 10 at the time of startup and normal power generation. At the time of start-up, for example, power can be supplied from the high voltage battery 12 to the fuel system auxiliary device and the air system auxiliary device. At the time of normal power generation, for example, the fuel system auxiliary device and the high voltage battery 12 or the SOFC 10 Electric power can be supplied to the air system auxiliary machine.

  The high voltage battery 12 is composed of a secondary battery such as a lithium ion battery, for example. Further, the high voltage battery 12 is charged by the generated power of the SOFC 10 adjusted by the FC insulation converter 14 or external power. Further, the high voltage battery 12 appropriately supplies power to the first travel motor 20 based on the power request from the first travel motor 20.

  The FC insulation converter 14 is configured to supply the generated power of the SOFC 10 (or regenerative power generated by the second travel motor 26) to the first travel motor 20, or to charge the high-voltage battery 12 with the generated power or the like. It is comprised by the insulation type DCDC converter which adjusts the output voltage. The FC insulation converter 14 includes a low voltage side switching unit 14 a connected to the low voltage line 22 on the SOFC 10 side, and a high voltage side switching unit 14 b connected to the high voltage line 16 connected to the high voltage battery 12 and the first traveling motor 20. The insulation transformer 14c connects the low-voltage side switching unit 14a and the high-voltage side switching unit 14b.

  In the FC insulation converter 14, the low voltage side switching unit 14a and the high voltage side switching unit 14b are electrically insulated, but are magnetically coupled by the insulation transformer 14c. The low voltage side switching unit 14a converts the DC voltage output from the SOFC 10 into an AC voltage and outputs the AC voltage to the primary coil of the insulating transformer 14c. Further, the high voltage side switching unit 14b converts the AC voltage output from the secondary coil of the insulating transformer 14c into a DC voltage and outputs the high voltage line.

  The insulation transformer 14c increases the number of turns of the primary side coil and the secondary side coil corresponding to the boost ratio so that the voltage of the input low voltage line 22 can be boosted at a predetermined boost ratio and output to the high voltage line 16. The ratio is set. Hereinafter, the step-up ratio determined according to the turn ratio of the insulating transformer 14c is also referred to as “basic step-up ratio”. Therefore, the AC voltage output from the low-voltage side switching unit 14a is supplied to the primary coil of the insulating transformer 14c to generate a magnetic flux, and the magnetic flux generates an induced electromotive force on the secondary side of the insulating transformer 14c. An AC voltage determined by the “boost ratio” is input to the high voltage side switching unit 14b.

  Further, although not shown in FIG. 1, the FC insulation converter 14 includes a resonance circuit composed of a capacitor, a reactor, or the like for finely adjusting the basic step-up ratio according to the turn ratio of the insulation transformer 14c.

  With the above configuration, in the power control system 100 of the present embodiment, the required power of the first traveling motor 20 is obtained by performing predetermined switching control on the low-voltage side switching unit 14a or the high-voltage side switching unit 14b of the FC insulation converter 14. Alternatively, the output voltage of the SOFC 10 (the voltage of the low voltage line 22) can be adjusted so that the generated power of the SOFC 10 can be supplied to the high voltage battery 12 in response to a charge request.

  In particular, since the FC insulation converter 14 includes the insulation transformer 14c, the low voltage line 22 (SOFC 10 side) and the high voltage line 16 (high voltage battery 12 side) sandwiching the FC insulation converter 14 are electrically connected. While being insulated, power can be supplied from the SOFC 10 to the high voltage battery 12.

  The first travel motor 20 is a three-phase AC motor. The first traveling motor 20 is driven by electric power supplied from the high voltage battery 12 and is further assisted by auxiliary electric power supplied from the SOFC 10 via the FC insulation converter 14. Further, the first traveling motor 20 is provided with a first motor inverter 18 that converts DC power supplied from the high voltage battery 12 into AC power. The first traveling motor 20 is used, for example, to drive the front wheels of an electric vehicle. In addition, the 1st motor inverter 18 converts this into direct-current regenerative power, and supplies it to the high voltage line 16, when the 1st driving motor 20 is generating alternating current regenerative power.

  Similar to the first travel motor 20, the second travel motor 26 is a three-phase AC motor. The second traveling motor 26 is driven by electric power supplied from the SOFC 10. The second traveling motor 26 is provided with a second motor inverter 24 that converts DC power supplied from the high voltage battery 12 into AC power. The second traveling motor 26 is used, for example, to drive the rear wheels of the electric vehicle. In addition, the 2nd motor inverter 24 converts this into direct-current regenerative electric power, and supplies it to the low voltage line 22 when the 2nd traveling motor 26 is generating alternating-current regenerative electric power.

  The controller 9 is constituted by a computer, particularly a microcomputer, provided with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 9 is programmed to execute the processing of the present embodiment. Note that the controller 9 may be configured as a single device, or may be divided into a plurality of devices, and each control of the present embodiment may be configured to be distributed and processed by the plurality of devices.

  As will be described later, the controller 9 reads the magnitude of the target output transmitted from the electric vehicle side, and the response to the target output is a high output state (FIG. 2), a normal output state (FIG. 1), a medium output state ( 3), it is determined whether the output state is low (FIG. 4). Further, the controller 9 determines that a regenerative power generation state (FIG. 5) is present when a brake operation is performed. Then, the controller 9 determines the SOFC 10, the high voltage battery 12, the FC insulation converter 14, the first motor inverter 18 (first travel motor 20), and the second motor inverter 24 (second travel motor 26) according to each state. Drive control is performed.

  In the present embodiment, in the normal output state (FIG. 1) or the high output state (FIG. 2), the first traveling motor 20 is supplemented from the power of the high voltage battery 12 and the SOFC 10 supplied via the FC insulation converter 14. The second traveling motor 26 is driven by electric power from the SOFC 10 by being driven by electric power. Further, in the medium output state (FIG. 3), the FC insulation converter 14 is stopped, the first traveling motor 20 is driven by the power of the high voltage battery 12, and the second traveling motor 26 is driven by the power from the SOFC 10. . Further, in the low output state (FIG. 4), the FC insulation converter 14 is stopped and the power supply to the first travel motor 20 is stopped, and the second travel motor 26 is driven by the power from the SOFC 10.

  That is, in the present embodiment, in the normal output state (FIG. 1) and the high output state (FIG. 2), the front wheels (or rear wheels) connected to the first travel motor 20 are the drive wheels that mainly drive the electric vehicle. In the low output state, the rear wheels (or front wheels) connected to the second travel motor 26 are drive wheels that mainly drive the electric vehicle.

  Here, it is preferable that the rated output of the first travel motor 20 is designed to be larger than that of the second travel motor 26. Thereby, the high voltage battery 12 (the output is larger than that of the SOFC 10) is directly connected to the first traveling motor 20 having a large rated output without passing through the FC insulation converter 14. Therefore, in the normal output state (FIG. 1) and the high output state (FIG. 2), the electric power supplied from the SOFC 10 to the high voltage line 16 via the FC insulation converter 14 only supports a certain amount of the output of the high voltage battery 12. The high output of the FC isolation converter 14 is avoided.

  Note that the power control system 100 may be provided with a relay on the low voltage line 22 or the like for physically disconnecting the connection between the high voltage battery 12 and the SOFC 10 when the SOFC 10 is stopped. .

  According to the power control system 100 having the above configuration, the high voltage battery 12 and the first travel motor 20 are electrically insulated from the low voltage side SOFC 10 and the second travel motor 26 by the FC isolation converter 14. Meanwhile, the generated power of the SOFC 10 can be supplied to the first traveling motor 20, or the high-voltage battery 12 can be charged with the generated power.

[Operation of First Embodiment]
FIG. 6 is a diagram illustrating a comparative example of the power control system 100 according to the first embodiment. Operation | movement of the power control system 100 of 1st Embodiment is demonstrated, comparing with the comparative example shown in FIG.

  As shown in FIG. 6, in the comparative example of the power control system 100 of the present embodiment, the second travel motor 26 is not attached to the low voltage line 22, and the drive control of the electric vehicle is performed only by the first travel motor 20. Done. The electric power is supplied from the high voltage battery 12 and the SOFC 10 in response to a request from the first traveling motor 20 (first motor inverter 18), and the burden on the high voltage battery 12 is reduced to reduce the load on the electric vehicle. The cruising range is increased.

  By the way, from the viewpoint of improving the layout flexibility of the SOFC 10 in the electric vehicle, the output voltage is designed to be a voltage lower than 60V (30V in FIG. 6) so as not to be a target of the high voltage safety requirement target part, In addition, it has been proposed to construct a system in which the SOFC 10 and the high voltage battery 12 are electrically insulated from each other.

  Therefore, as shown in FIG. 6, for example, when the target output of the first travel motor 20 required from the electric vehicle is 80 kW, 50 kW is output from the high voltage battery 12 to the first travel motor 20 and the output from the SOFC 10 It is conceivable to perform control that satisfies the target output by outputting (30 kW) to the first traveling motor 20 via the FC insulation converter 14 having a high step-up ratio.

  In order to perform the control, the output of the FC insulation converter 14 is required to be 30 kW. However, in order to construct such a high-output FC insulation converter 14, it is inevitable to increase the size and weight of the insulation transformer 14c and the like, and it is difficult to mount it on an electric vehicle.

  Therefore, in the present embodiment, as shown in FIG. 1 (normal output state), the second traveling motor 26 is connected to the low voltage line 22 via the second motor inverter 24, and the target output of the entire power control system 100 is obtained. The first traveling motor 20 and the second traveling motor 26 are dispersed. The second traveling motor 26 is configured to receive power supply from the SOFC 10 without going through the FC insulation converter 14.

  Thereby, the FC insulation converter 14 does not need to supply high output power to the first travel motor 20, and the FC insulation converter 14 can be mounted on an electric vehicle in a state where the FC insulation converter 14 can be mounted on the vehicle.

  Here, the second motor inverter 24 (the same applies to the first motor inverter 18) does not require a magnetic component such as a transformer or a coil, and is mainly composed of only a power element capacitor, so that a circuit configuration with a large current is possible. It is. Moreover, the electric power sharing with the FC insulation converter 14 can be aimed at as needed.

  Therefore, the FC insulation converter 14 can supply a part of the power generated by the SOFC 10 to the high voltage line 16. As a result, a part of the target output of the first traveling motor 20 can be supplied from the FC insulation converter 14, and the burden on the high voltage battery 12 can be reduced.

  In the normal output state shown in FIG. 1, the controller 9 includes the SOFC 10, the high voltage battery 12, the FC insulation converter 14, the first motor inverter 18 (first traveling motor 20), and the second motor inverter 24 (second traveling motor 26). Is driving. For example, as shown in FIG. 1, when the target output of the power control system 100 required from the electric vehicle is 80 kW, the target output is 56 kW for the first travel motor 20 and 24 kW for the second travel motor 26. Are dispersed.

  For example, the SOFC 10 is designed to generate power of 30 kW (30 V × 1000 A). Of the generated power, 24 kW is supplied to the second traveling motor 26 and 6 kW is supplied to the FC insulation converter 14. Therefore, the second traveling motor 26 is driven by an output of 24 kW (30 V × 800 A).

  On the other hand, in the first traveling motor 20, 6 kW (30 V × 200 A) of the allocated target output 56 kW is supplied from the FC insulation converter 14, and 50 kW is supplied from the high voltage battery 12. Therefore, also in the present embodiment, the SOFC 10 (FC insulation converter 14) covers a part of the target output of the first traveling motor 20, whereby the burden on the high voltage battery 12 can be reduced.

  FIG. 2 is a diagram illustrating a high output state in the power control system 100 of the first embodiment. The power control system 100 of the first embodiment can reasonably generate an output higher than that of the comparative example shown in FIG. In the high output state shown in FIG. 2, the controller 9 includes the SOFC 10, the high voltage battery 12, the FC insulation converter 14, the first motor inverter 18 (first traveling motor 20), and the second motor inverter 24 (second traveling motor 26). Is driving. Then, as shown in FIG. 2, by raising the output of the high voltage battery 12 to 74 kW, the first traveling motor 20 can output 80 kW, the second traveling motor 26 can output 24 kW, and a total driving force of 104 kW. Even in such a high output state, since the output of the FC insulation converter 14 is 6 kW, the burden on the FC insulation converter 14 does not increase.

  FIG. 3 is a diagram illustrating a state in which the drive of the FC insulation converter 14 is stopped in the power control system 100 of the first embodiment. FIG. 3 shows an operation when the target output of the power control system 100 required from the electric vehicle is in a medium output state (which can be defined as an output larger than the output of the SOFC 10) lower than 80 kW (normal output state). Yes. In the medium output state shown in FIG. 3, the controller 9 drives the SOFC 10, the high voltage battery 12, the first motor inverter 18 (first traveling motor 20), and the second motor inverter 24 (second traveling motor 26) to generate FC. The drive of the insulating converter 14 is stopped. That is, in the medium output state, the drive of the FC insulation converter 14 is stopped, the first travel motor 20 is driven by the power from the high voltage battery 12, and the second travel motor 26 is driven by the power from the SOFC 10. As described above, when the target output corresponds to the medium output state, the drive of the FC insulation converter 14 can be stopped, so that the power loss in the FC insulation converter 14 can be avoided.

  FIG. 4 is a diagram illustrating a state in which the drive of the FC insulation converter 14 and the first travel motor 20 is stopped in the power control system 100 of the first embodiment. FIG. 4 shows an operation in a low output state in which the target output of the power control system 100 required from the electric vehicle is lower than the maximum output (for example, 30 kW) of the SOFC 10. In the low output state, the controller 9 drives the SOFC 10, the second motor inverter 24 (second travel motor 26), the high voltage battery 12, the first motor inverter 18 (first travel motor 20), and the FC insulation converter 14. The drive is stopped. That is, in the low output state, the second traveling motor 26 is only driven by being supplied with electric power from the SOFC 10 via the second motor inverter 24, and the high voltage battery 12, the first traveling motor 20, and the FC isolation converter 14 are driven. The drive is stopped.

  Thus, when the target output is low, the drive of the FC insulation converter 14 can be stopped, so that power loss in the FC insulation converter 14 can be avoided. Furthermore, since the driving of the high voltage battery 12 (and the first travel motor 20) can also be stopped, the SOC (charge rate) of the high voltage battery 12 can be maintained.

  In this case, the high-voltage battery 12 can also be charged by driving the FC insulation converter 14 and supplying a part of the power generated by the SOFC 10 to the high-voltage line 16.

  FIG. 5 is a diagram illustrating a state in which regenerative power is generated in the power control system 100 of the first embodiment. When the driver performs a braking operation while the electric vehicle is traveling, regenerative braking is generated in the first traveling motor 20 and the second traveling motor 26, and the speed of the electric vehicle decreases. At this time, the controller 9 stops the output of the high voltage battery 12. In addition, the controller 9 stops the output of the SOFC 10 or reduces it to a level that can cover the drive power of the fuel system auxiliary equipment and air system auxiliary equipment of the SOFC 10.

  On the other hand, in the 1st driving | running | working motor 20 and the 2nd driving | running | working motor 26, the regenerative electric power accompanying regenerative braking generate | occur | produces (regenerative electric power generation state). For this reason, the controller 9 drives the first motor inverter 18 so that the primary side becomes the first traveling motor 20 and the secondary side becomes the high voltage line 16. Thereby, the regenerative electric power generated by the first traveling motor 20 can be charged to the high voltage battery 12. Further, the controller 9 drives the FC insulation converter 14 and drives the second motor inverter 24 so that the primary side becomes the second traveling motor 26 and the secondary side becomes the low voltage line 22. As a result, the regenerative power generated by the second traveling motor 26 is charged to the high voltage battery 12 via the FC insulation converter 14 under the condition that the maximum output of the FC insulation converter 14 (for example, 6 kW (30 V × 200 A)) or less. Can do.

[Effect of the first embodiment]
The power control system 100 of the first embodiment includes a SOFC 10 (power generation device) that generates low-voltage power, a high-voltage battery 12 that is charged with power generated by the SOFC 10, and power supply from the high-voltage battery 12. Receiving first traveling motor 20 (first external load), FC insulation converter 14 (power converter) connected between SOFC 10 and high voltage battery 12, and second traveling motor 26 receiving power supply from SOFC 10 (Second external load), and FC insulation converter 14 includes an insulation type power converter.

  According to the above configuration, since the insulation type power converter is used as the power converter (FC insulation converter 14), the SOFC 10 (power generation device) having a voltage lower than that of the high voltage battery 12 can be used. Sex can be secured. Therefore, even when a problem occurs in the SOFC 10, the risk caused by the high voltage of the SOFC 10 can be reduced.

  Since the insulated power converter (FC insulated converter 14) uses magnetic parts, its size increases when the current is increased. However, if it is the said aspect, since the output of SOFC10 is directly supplied to the 2nd traveling motor 26 without passing through the FC insulation converter 14, the increase in the passing current of the said insulation type power converter can be avoided. Therefore, for example, even in an electric vehicle with strict layout requirements, it is possible to mount the FC isolated converter 14 having a large output in a size that can be mounted on a vehicle, and realize a range extender system that extends the cruising distance of the electric vehicle by the power supplied by the SOFC 10. be able to. Furthermore, by avoiding an increase in the passing current of the insulated power converter, a loss in the insulated power converter can be avoided, and the system efficiency can be improved.

  In the first embodiment, power is supplied from the high voltage battery 12 to the first travel motor 20, power is supplied from the SOFC 10 to the second travel motor 26, and the power generated by the SOFC 10 is passed through the FC insulation converter 14. And supplied to the first traveling motor 20 as auxiliary power.

  With the above configuration, the FC insulation converter 14 only needs to be designed to the extent that it can support the electric power supplemented from the SOFC 10 to the first traveling motor 20, so that the entire electric power of the SOFC 10 is transferred to the first traveling motor 20 via the FC insulation converter 14. As compared with the case of supplying to FC, it is possible to reduce the size and cost of the FC insulating converter 14. Moreover, the power loss in the FC insulation converter 14 can be reduced.

  In the first embodiment, power is supplied from the high voltage battery 12 to the first travel motor 20, power is supplied from the SOFC 10 to the second travel motor 26, and the FC insulation converter 14 is stopped.

  With the above configuration, power loss in the FC insulation converter 14 can be avoided.

  In the first embodiment, power is supplied from the SOFC 10 to the second traveling motor 26, and the FC insulating converter 14 is stopped.

  With the above configuration, when the target output of the power control system 100 can be covered only by the second traveling motor 26, the SOFC 10 can be supplied directly from the SOFC 10 to the second traveling motor 26 without passing through the FC insulation converter 14. Since the electric vehicle can be driven with this power, it is possible to avoid power loss in the FC insulation converter 14 and improve system efficiency.

  In the first embodiment, when regenerative power is generated from the second traveling motor 26, it is supplied as power for charging the high-voltage battery 12 via the FC insulation converter 14.

  With the above configuration, the SOC (charge rate) of the high-voltage battery 12 can be increased and the system efficiency can be improved.

  As described above, various modifications can be made in the power control system 100 of the first embodiment described above. For example, the output voltage of the SOFC 10 can be set as appropriate according to the requirements of the device in which the power control system 100 is mounted.

  As described above, the SOFC 10 is less than a predetermined voltage, which is a standard that is determined as a high-voltage safety requirement target part that is subject to a predetermined safety requirement in an apparatus (such as an automobile or a railcar) on which the power control system 100 is mounted. It may be configured to take the maximum output voltage.

  In other words, depending on the device on which the power control system 100 is mounted, more stringent safety measures such as the arrangement position in the device and a predetermined insulation treatment are required from the viewpoint of securing electrical safety to the human body and the like. The parts subject to high voltage safety requirements may be stipulated by laws and regulations. The determination as to whether a certain component is such a high-voltage safety requirement target component is usually made based on the magnitude of the operating voltage of the component.

  In view of such circumstances, the maximum output voltage of the SOFC 10 is determined by setting the reference voltage that is determined to be a high-voltage safety request target component according to the device on which the power control system 100 is mounted as the predetermined voltage. Can be less than the voltage determined to be a high-voltage safety requirement target part.

  As a result, the SOFC 10 can be removed from the high-voltage safety requirement target parts determined from the viewpoint of the electrical safety of the device in which the power control system 100 is mounted, and the layout freedom of the SOFC 10, that is, the layout freedom of the entire electric vehicle. Can be improved.

  In particular, the SOFC 10 may be configured such that the maximum output voltage is less than 60V. By setting the maximum output voltage of the SOFC 10 in this way, when the power control system 100 of the present embodiment is particularly mounted on an automobile, the SOFC 10 can be more reliably removed from the high-voltage safety requirement target component, The layout freedom of the SOFC 10, that is, the layout freedom of the entire electric vehicle can be improved.

  Here, in the case of automobiles, high voltage safety requirements are required from the viewpoint of safety in the front area and rear area of the vehicle (hereinafter also simply referred to as “collision area”) that are assumed to be relatively damaged during a collision. It is required not to arrange the target parts. And the voltage used as the reference | standard judged as a high voltage safety request | requirement target component is generally set to 60V.

  In such a situation, the SOFC 10 is configured such that its maximum output voltage is less than 60V and excluded from the target of the high voltage safety requirement target component. The SOFC 10 can also be arranged in a front region or a rear region of a vehicle that is not assumed.

  Furthermore, even if the maximum output voltage of the SOFC 10 is less than 60 V as described above, when the SOFC 10 is directly electrically connected to a high voltage system such as the high voltage battery 12, the SOFC 10 becomes a high voltage safety required component together with the high voltage battery 12. Applicable.

  However, in the power control system 100 of this embodiment, as already described, the SOFC 10, the high voltage battery 12, and the first travel motor 20 are electrically insulated from each other by the FC isolation converter 14. Thereby, the SOFC 10 can be a component independent of the high voltage system including the high voltage battery 12. Therefore, the SOFC 10 can be more reliably removed from the high-voltage safety requirement target component by the FC insulation converter 14. As a result, the SOFC 10 can be arranged in any area including the collision area of the automobile, so that the degree of freedom in layout of the entire vehicle can be improved.

  By the way, JP-A-2008-199802 is mentioned as a prior art relevant to this invention. In the prior art, the fuel cell is connected to one side of the DC-DC converter, the battery is connected to the other side of the DC-DC converter, and the first motor is connected to the connection line connecting the fuel cell and the DC-DC converter. A configuration is disclosed in which a second motor is electrically connected to a connection line that is electrically connected and connects a battery and a DC-DC converter (prior art FIG. 1). Only when the power to be supplied to the first motor exceeds the power that can be generated by the fuel cell, the power supply from the battery to the first motor is permitted via the DC-DC converter (prior art paragraph [0039] ]).

  However, in the prior art, the rated continuous output of the first motor is higher than that of the second motor, and the first motor drives the main drive wheel (prior art paragraph [0034]), and the battery is the first motor. Are connected via a DC-DC converter. Therefore, in order to supply electric power from the battery to the first motor having a large rated continuous output, it is necessary to apply a high output as the DC-DC converter. Furthermore, as described above, in order to remove the fuel cell from the high voltage safety requirement target part, it is necessary to apply an insulated type DC-DC converter. However, it is difficult to realize an insulated DC-DC converter having a high output in a size that can be mounted in a vehicle. Even if it can be mounted in a vehicle, the cost increases and the conversion efficiency of the DC-DC converter decreases. Cause problems.

  However, in the present embodiment, as described above, the rated output of the first traveling motor 20 is designed to be larger than the rated output of the second traveling motor 26. Thereby, the high voltage battery 12 (the output is larger than that of the SOFC 10) is directly connected to the first traveling motor 20 having a large rated output without passing through the FC insulation converter 14. Therefore, in the normal output state (FIG. 1) and the high output state (FIG. 2), the electric power supplied from the SOFC 10 to the high voltage line 16 via the FC insulation converter 14 only supports a certain amount of the output of the high voltage battery 12. The high output of the FC isolation converter 14 is avoided.

[Second Embodiment]
Hereinafter, a second embodiment will be described. In the following description, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted unless necessary. FIG. 7 is a diagram illustrating the configuration of the power control system 100 according to the second embodiment.

  The power control system 100 of the second embodiment includes a third travel motor 30 (third external load) connected in parallel with the second travel motor 26, and the SOFC 10 includes the second travel motor 26 and the third travel motor 30. It is the structure which supplies electric power to.

  The third traveling motor 30 is electrically connected to the low voltage line 22 via the third motor inverter 28. The third traveling motor 30 can be used as the driving force for the rear wheels of the electric vehicle, like the second traveling motor 26. The third motor inverter 28 is connected to the low voltage line 22 similarly to the second motor inverter 24, converts the DC voltage output from the SOFC 10 into an AC voltage, and outputs the AC voltage to the third traveling motor 30. In addition, the 3rd motor inverter 28 converts this into direct-current regenerative power, when the 3rd driving | running | working motor 30 is generating alternating current regenerative power, and supplies it to the low voltage line 22. FIG.

  In addition to the third traveling motor 30, the third external load is applied to a fuel system auxiliary device and air system auxiliary device for driving the SOFC 10, and an auxiliary device for an electric vehicle (air conditioner, headlight, etc.). Can do. A plurality of third external loads may be connected to the low voltage line 22.

  As in the first embodiment, the controller 9 includes a high output state (FIG. 2), a normal output state (FIG. 1), a medium output state (FIG. 3), a low output state (FIG. 4), and a regenerative power generation state (FIG. 5) according to each state, the SOFC 10, the high voltage battery 12, the FC insulation converter 14, the first motor inverter 18 (first traveling motor 20), the second motor inverter 24 (second traveling motor 26), and the third motor. Drive control of the inverter 28 (third traveling motor 30) is performed.

  As shown in FIG. 1, when the target output of the power control system 100 of the first embodiment requested from the electric vehicle is 80 kW, a target output of 24 kW is assigned to the second travel motor 26 of the first embodiment. It is done.

  On the other hand, as shown in FIG. 7, when the target output of the power control system 100 of the second embodiment required from the electric vehicle is 80 kW, the target output of 12 kW for the second travel motor 26 of the second embodiment. And a target output of 12 kW is assigned to the third traveling motor 30 of the second embodiment.

  Thus, by assigning the target output on the low voltage line 22 side to the second travel motor 26 and the third travel motor 30, the burden on the second motor inverter 24 and the third motor inverter 28 can be reduced.

[Third Embodiment]
FIG. 8 is a diagram illustrating the configuration of the power control system 100 according to the third embodiment. In the power control system 100 of the third embodiment, the FC insulation converter 14-1 and the FC insulation converter 14-2 are connected in parallel to the high voltage line 16. The SOFC 10-1 is connected to the FC insulation converter 14-1 via the low voltage line 22-1 and the second traveling motor 26-1 is connected to the low voltage line 22-1 via the second motor inverter 24-1. It is connected. Similarly, the SOFC 10-2 is connected to the FC insulation converter 14-2 via the low voltage line 22-2, and the second traveling motor 26-2 is connected to the low voltage line 22-2 via the second motor inverter 24-2. Is connected. Here, for example, the SOFC 10-1 and the SOFC 10-2 are the same as the SOFC 10, and other components having the same reference numerals are also handled in the same manner.

  In the present embodiment, one background in which two SOFCs 10-1 and 10-2 are arranged will be described. However, the background described below does not limit the configuration of the present embodiment.

  As described above, if the SOFC 10 having a small output voltage is configured, the electrical safety of the SOFC 10 is improved. On the other hand, in the case of the SOFC 10 with a low output voltage, for example, when the required generated power for the SOFC 10 is large, such as when the required charge amount of the high-voltage battery 12 is relatively large, the SOFC 10 is taken out from the SOFC 10 to secure the required generated power The current needs to be increased. However, there is a limit to the amount of current that can be extracted from a single SOFC 10.

  On the other hand, in the power control system 100 of the present embodiment, even when the SOFC 10 having a small output voltage is disposed, the two SOFCs 10-1 and 10-2 are more suitably secured from the viewpoint of securing the required generated power. Are arranged in parallel.

  Further, even when two SOFCs 10-1 and 10-2 are arranged in parallel, it is possible to collectively control the extraction currents from the two SOFCs 10-1 and 10-2 by one FC insulation converter 14. is there. However, it is assumed that these output characteristics (IV characteristics) vary due to factors such as individual differences between the two SOFCs 10-1 and 10-2.

  In the two SOFCs 10-1 and 10-2 having different output characteristics as described above, when the same extraction current is extracted from each of the SOFCs 10-1 and 10-2, the degree of decrease in the respective voltages is different. The voltage between 10-2 will vary. In particular, when the extraction current increases, the voltage variation due to the difference in output characteristics increases (see FIG. 10).

  Therefore, when the currents taken out from the two SOFCs 10-1 and 10-2 are collectively controlled by a single FC insulation converter 14, it is necessary to take out the current in accordance with the lower of these characteristics. There is. That is, a situation is assumed in which the lower of the output characteristics of the two SOFCs 10-1 and 10-2 becomes a bottleneck, and the performance of the higher output characteristics cannot be sufficiently obtained.

  The present inventors paying attention to such a situation, connect the FC insulation converter 14-1 and the FC insulation converter 14-2 to each of the SOFCs 10-1 and 10-2 individually, so that the SOFCs 10-1 and 10-2 are connected. The present inventors have conceived of controlling the extraction current in accordance with each output characteristic of -2. As a result, it is possible to extract individual suitable currents according to the output characteristics from any of the SOFCs 10-1 and 10-2.

  Based on the above knowledge, as shown in FIG. 8, the power control system 100 of the present embodiment is arranged in the low voltage line 22-1 between the SOFC 10-1 and the FC insulation converter 14-1 in addition to the above configuration. The low voltage side current sensor 32-1 and the low voltage side voltage sensor 34-1, and the low voltage side current sensor 32-2 and the low voltage side arranged in the low voltage line 22-2 between the SOFC 10-2 and the FC insulation converter 14-2. The voltage sensor 34-2 and the high-voltage side voltage sensor 36 disposed on the high-voltage line 16 on the output side of the FC insulation converter 14-1 and the FC insulation converter 14-2.

  The low voltage side current sensor 32-1 detects the current of the low voltage line 22-1 corresponding to the extraction current of the SOFC 10-1 (hereinafter, also simply referred to as “first low voltage side current Ilow1”). The low voltage side voltage sensor 34-1 detects a voltage corresponding to the output voltage of the SOFC 10-1 (the input voltage of the FC insulation converter 14-1) (hereinafter also simply referred to as “first low voltage side voltage Vlow1”). To do.

  Further, the low voltage side current sensor 32-2 detects a current of the low voltage line 22-2 (hereinafter, also simply referred to as “second low voltage side current Ilow2”) corresponding to the extraction current of the SOFC 10-2. The low voltage side voltage sensor 34-2 detects a voltage corresponding to the output voltage of the SOFC 10-2 (the input voltage of the FC insulation converter 14-2) (hereinafter also simply referred to as “second low voltage side voltage Vlow2”). To do.

  Further, the high voltage side voltage sensor 36 is a voltage of the high voltage line 16 corresponding to the output voltage of the FC insulation converter 14-1 and the FC insulation converter 14-2 (hereinafter, also simply referred to as “high voltage side voltage Vhigh”). To detect.

  Furthermore, the power control system 100 includes a controller 90 as a transformer individual control unit that controls the FC insulation converter 14-1 and the FC insulation converter 14-2.

  The controller 90 is constituted by a computer, particularly a microcomputer, provided with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 90 is programmed to execute the processing of the present embodiment. The controller 90 may be configured as a single device, or may be divided into a plurality of devices, and may be configured so that each control of the present embodiment is distributedly processed by the plurality of devices.

  In the present embodiment, the controller 90 includes a first low-voltage side current detection value Ilow1d detected by the low-voltage side current sensor 32-1, a first low-voltage side voltage detection value Vlow1d detected by the low-voltage side voltage sensor 34-1. The second low voltage side current detection value Ilow2d detected by the low voltage side current sensor 32-2, the second low voltage side voltage detection value Vlow2d detected by the low voltage side voltage sensor 34-2, and the high voltage side voltage sensor 36. Based on the high-voltage side voltage detection value Vhighd, each of the FC insulation converter 14-1 and the FC insulation converter 14-2 is subjected to switching control to control the step-up ratio. Hereinafter, the control by the controller 90 will be described in more detail.

  FIG. 9 is a flowchart illustrating a control mode of the power control system 100 according to the third embodiment. In addition, each step shown in this flowchart is not necessarily limited to the order demonstrated below, and can replace each step in the possible range.

  As illustrated, in step S <b> 110, the controller 90 outputs power to the high voltage line 16 based on, for example, a detection value of a charge amount (SOC) sensor (not illustrated) or a value of auxiliary power supplied to the first travel motor 20. (Required power) is calculated.

  In step S120, the controller 190 calculates the total required generated power of the SOFC 10-1 and SOFC 10-2 from the calculated required power.

  In step S130, the controller 90 calculates the first low voltage side current target value Ilow1t and the second low voltage side current target value Ilow2t. Specifically, the controller 90 satisfies the calculated required generated power, and the first low voltage so that a deviation between the acquired first low voltage side voltage detection value Vlow1d and the second low voltage side voltage detection value Vlow2d is equal to or less than an allowable value ΔV. The side current target value Ilow1t and the second low voltage side current target value Ilow2t are calculated.

  That is, the controller 90 suppresses variations in the first low-voltage side voltage Vlow1 (the voltage of the SOFC 10-1) and the second low-voltage side voltage Vlow2 (the voltage of the SOFC 10-2) while satisfying the required power on the high voltage line 16 side. From the viewpoint, the first low-voltage side current target value Ilow1t (SOFC10-1 extraction current target value) and the second low-voltage side current target value Ilow2t (SOFC10-2 extraction current target value) are calculated.

  FIG. 10 is a diagram showing an outline of IV curves of two SOFCs 10-1 and SOFC 10-2 having different output characteristics. In the figure, the IV curve of SOFC 10-1 is indicated by a solid line, and the IV curve of SOFC 10-2 is indicated by a broken line. That is, in this embodiment, it is assumed that the output characteristics of the SOFC 10-1 are higher than the output characteristics of the SOFC 10-2.

  As understood from the figure, in the case of the SOFC 10-1 and SOFC 10-2 having different output characteristics, even if the same current is taken out, the output voltage corresponding to the same current is different. In particular, in the region where the extraction current increases, the difference between the first low-voltage side voltage Vlow1 and the second low-voltage side voltage Vlow2 increases. Therefore, in the present embodiment, from the viewpoint of reducing the difference between the first low-voltage side voltage Vlow1 and the second low-voltage side voltage Vlow2, the first low-voltage side current that is the target value of the extraction current from each of the SOFCs 10-1 and 10-2. The target value Ilow1t and the second low-voltage side current target value Ilow2t are set according to the respective output characteristics.

  For example, when the value of the first low-voltage side current Ilow1 indicated by the dotted line in FIG. 10 is set to the first low-voltage side current target value Ilow1t, the controller 90 sets the current corresponding to the first low-voltage side current target value Ilow1t to the SOFC10− 5 is a region where the second low-voltage side voltage detection value Vlow2d corresponding to the output voltage of the SOFC 10-2 falls within the allowable value ΔV or less with respect to the first low-voltage side voltage detection value Vlow1d in the case of taking out from 1 (FIG. 5). From the hatched area), the second low-voltage side current target value Ilow2t is selected in consideration of the total required generated power.

  In step S140, the controller 90 determines that the first low-voltage side current detection value Ilow1d and the second low-voltage-side current detection value Ilow2d are the first low-voltage-side current target value Ilow1t and the second low-voltage-side current target that are calculated in step S130, respectively. The step-up ratios of the FC insulation converter 14-1 and the FC insulation converter 14-2 are controlled so as to approach the value Ilow2t.

  As described above, in the present embodiment, each FC insulation converter 14-1 and FC insulation converter 14 capable of setting a suitable extraction current according to the output characteristics of the two SOFCs 10-1 and 10-2. -2 switching control is realized.

  In the above control, when a required current (required power) to the second traveling motor 26-1 (second motor inverter 24-1) side of the SOFC 10-1 is generated, Ilow1t is changed from the Ilow1t to the request. A value obtained by subtracting the current may be taken as the current. Similarly, when a required current (required power) to the second traveling motor 26-2 (second motor inverter 24-2) side of the SOFC 10-2 is generated, Ilow2t subtracts the required current from the Ilow2t. The obtained value may be taken as the current. Further, the magnitude of the required current to the second traveling motor 26-1 side of the SOFC 10-1 and the magnitude of the requested current to the second traveling motor 26-2 side of the SOFC 10-2 are made to coincide with each other, so that the second traveling motor It is also possible to make the output of 26-1 coincide with the output of the second traveling motor 26-2.

  When the output characteristics of the SOFC 10-1 and SOFC 10-2 are substantially the same, the above control is unnecessary, and the low-voltage side current sensors 32-1, 32-2, the low-voltage side voltage sensors 34-1 and 34-2, and the high-voltage The side voltage sensor 36 can be omitted.

[Fourth Embodiment]
FIG. 11 is a diagram illustrating the configuration of the power control system 100 according to the fourth embodiment. As shown in the figure, the power converter of the power control system 100 of this embodiment includes an auxiliary device that boosts the output voltage of the FC insulation converter 14 at a predetermined boost ratio in addition to the FC insulation converter 14 described in the first embodiment. A non-insulated boost converter 44 as a booster is included.

  The non-insulated boost converter 44 is configured as a boost converter of a charge pump system or the like that can set a boost ratio within a certain range by switching control. In the present embodiment, the non-insulated boost converter 44 is connected between the FC insulating converter 14 and the high-voltage battery 12.

  In the power control system 100 of the present embodiment having the above configuration, the FC insulation converter 14 boosts the output voltage of the SOFC 10 in the low voltage line 22 by the basic boost ratio and outputs it to the intermediate voltage line 38. The non-insulated boost converter 44 boosts the voltage of the medium voltage line 38 at a predetermined boost ratio (hereinafter also referred to as “auxiliary boost ratio”) and outputs the boosted voltage to the high voltage line 16.

  That is, in the present embodiment, the output voltage of the SOFC 10 is boosted in two steps in the order of the FC isolated converter 14 and the non-insulated boost converter 44 and then supplied to the high voltage battery 12.

  In particular, in the present embodiment, the output voltage of the SOFC 10 is boosted at a relatively large basic boost ratio by the booster circuit (insulating transformer 14c) of the first-stage FC isolation converter 14, and the second-stage non-insulated booster is boosted. The auxiliary boost ratio can be adjusted with high accuracy by the control of the converter 44. As a result, the boost ratio (basic boost ratio x auxiliary boost ratio) with respect to the actual output voltage of the SOFC 10 by the FC isolated converter 14 and the non-insulated boost converter 44 is suitably set according to the required charging power of the high voltage battery 12 and the like. It becomes possible to adjust.

  More specifically, in the power control system 100 of the present embodiment, the output voltage of the SOFC 10 basically reaches the vicinity of a desired target voltage corresponding to the required charging power of the high voltage battery 12 by the basic boosting of the FC insulation converter 14. Boosted.

  However, it is assumed that the boost ratio of the output voltage of the SOFC 10 needs to be appropriately adjusted in a relatively short time due to, for example, fluctuations in required power of the high voltage battery 12. In the present embodiment, the non-insulated boost converter 44 can suitably cope with the adjustment of the substantial boost ratio of the output voltage of the SOFC 10 in a relatively short time.

  Further, in the present embodiment, as described above, the output voltage of the SOFC 10 is set to a voltage (less than 60V) lower than the voltage that is the target of the high voltage safety requirement target part, and power is supplied to the high voltage line 16 with a predetermined voltage. As described above, the boost ratios of the FC isolated converter 14 and the non-insulated boost converter 44 can be controlled.

  Therefore, the power control system 100 of the present embodiment includes a low voltage side current sensor 32 and a low voltage side voltage sensor 34 disposed in the low voltage line 22 and a medium voltage line 38 as illustrated in FIG. The voltage side current sensor 40 and the medium voltage side voltage sensor 42, and the high voltage side voltage sensor 36 disposed on the high voltage line 16 are included.

  The low voltage side current sensor 32 detects a low voltage side current Ilow corresponding to the output current of the SOFC 10. Further, the low voltage side voltage sensor 34 detects the low voltage side voltage Vlow which is the voltage of the low voltage line 22.

  Further, the medium voltage side current sensor 40 detects the medium voltage side current Imed corresponding to the input current from the FC isolated converter 14 to the non-insulated boost converter 44. Further, the medium voltage side voltage sensor 42 detects a medium voltage side voltage Vmed which is a voltage of the medium voltage line 38.

  Further, the high voltage side voltage sensor 36 detects a high voltage side voltage Vhigh which is a voltage of the high voltage line 16 (corresponding to a voltage of the high voltage battery 12).

  Furthermore, the power control system 100 includes a controller 190 that controls the FC isolated converter 14 and the non-insulated boost converter 44.

  The controller 190 is constituted by a computer, particularly a microcomputer, provided with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 90 is programmed to execute the processing of the present embodiment. Note that the controller 190 may be configured as a single device, or may be divided into a plurality of devices, and each control of the present embodiment may be configured to be distributed and processed by the plurality of devices.

  In this embodiment, the controller 190 detects the low voltage side current detection value Ilowd detected by the low voltage side current sensor 32, the low voltage side voltage detection value Vlowd detected by the low voltage side voltage sensor 34, and the medium voltage side current sensor 40. Based on the detected medium voltage side current detection value Imedd, the medium voltage side voltage detection value Vmedd detected by the medium voltage side voltage sensor 42, and the high voltage side voltage detection value Vhighd detected by the high voltage side voltage sensor 36, the FC insulation converter 14 and the non-insulated boost converter 44 are controlled. Hereinafter, the control by the controller 190 in this embodiment will be described in more detail.

  FIG. 12 is a flowchart illustrating a control mode of the power control system 100 according to the fourth embodiment. In addition, each step shown in this flowchart is not necessarily limited to the order demonstrated below, and can replace each step in the possible range.

  As illustrated, in step S210, the controller 190 accepts the high voltage battery 12 based on, for example, a charge amount detection value (or estimated value) of the high voltage battery 12 detected by a charge amount (SOC) sensor (not shown). The possible power (required charging power) is calculated.

  In step S220, the controller 190 calculates the required generated power for the SOFC 10 from the calculated required charging power of the high-voltage battery 12. At this time, if there is a required power from the second traveling motor 26, the required power for the second traveling motor 26 is added to the required generated power.

  In step S230, the controller 190 calculates the extraction current correction target value of the SOFC 10 (hereinafter also referred to as “first extraction current target value”) based on the calculated required generated power and the low-voltage side voltage detection value Vlowd. That is, the first extraction current target value is a certain upper limit at which the voltage of the low voltage line 22 (low voltage Vlow) is the target of the high voltage safety requirement target part while satisfying the charge power requirement of the high voltage battery 12. This is the target value of the extraction current (low-voltage side current Ilow) of the SOFC 10 calculated from the viewpoint of limiting so as not to exceed the value.

  Specifically, in the present embodiment, the controller 190 first calculates the basic current extraction target value of the SOFC 10 based on the calculated required generated power. Then, based on the output characteristic (IV characteristic) of the SOFC 10, a value obtained by correcting the basic extraction current target value so that the low-voltage side voltage detection value Vlowd is less than a predetermined upper limit voltage Vlim (for example, 60V) is used as the first extraction current target value. Set as. As described above, when there is a required power (required current) from the second traveling motor 26, the first extracted current target value is a value obtained by subtracting the requested current from the first extracted current target value. Apply.

  Note that the first target current value is a target value that is calculated from the viewpoint of limiting the low-voltage-side voltage detection value Vlowd while satisfying the required generated power, and therefore is determined based on the original first target current value. The value is set to a value equal to or greater than the extraction current target value.

  In step S240, the controller 190 controls the FC isolated converter 14 and the non-insulated boost converter 44 based on the first target current value calculated in step S230 and the high-voltage side voltage detection value Vhighd.

  Specifically, the controller 190 performs switching control of the FC isolated converter 14 and the non-insulated boost converter 44 so that the low-voltage-side current detection value Ilowd approaches the first extraction current target value, so that the total boost ratio (basic boost ratio) Ratio + auxiliary boost ratio).

  Therefore, according to the present embodiment, an aspect of control of each converter capable of charging the high voltage battery 12 with desired power while maintaining the low voltage side voltage Vlow below the upper limit voltage Vlim (for example, less than 60 V) is provided. Will be.

  Here, in the power control system 100 of the present embodiment, the low voltage line 22 and the medium voltage line 38 are electrically insulated by the insulation transformer 14 c of the FC insulation converter 14. Therefore, when the low-voltage side voltage Vlow that is the voltage of the low-voltage line 22 is maintained below the upper limit voltage Vlim, the operating voltage of the low-voltage line 22 on the input side of the FC isolation converter 14 and the SOFC 10 is substantially less than the upper limit voltage Vlim. It can be. That is, the electrical safety of the low voltage line 22 and the SOFC 10 can be further improved.

  In particular, when the power control system 100 of the present embodiment is mounted on an automobile, if the upper limit voltage Vlim is set to a value less than 60V, the operating voltage of the low voltage line 22 and the SOFC 10 is substantially less than 60V. Since they can be set to parts, they can be removed from the already described high voltage safety required parts.

  As a result, when the power control system 100 according to the present embodiment is mounted on an automobile, the layout layout flexibility on the vehicle of the low voltage line 22 and the SOFC 10 can be improved.

  Furthermore, in the power control system 100 of the present embodiment, the SOFC 10 may be configured so that the substantial maximum output voltage of the SOFC 10 is less than 60V. This makes it possible to more reliably maintain the low-voltage components including the SOFC 10 and the low-voltage line 22 in combination with the control in which the low-voltage side voltage Vlow is maintained below 60V. Electrical safety can be further enhanced.

[Fifth Embodiment]
FIG. 13 is a diagram illustrating the configuration of the power control system 100 according to the fifth embodiment. As illustrated, in the present embodiment, the arrangement of the non-insulated boost converter 44 and the FC insulating converter 14 is changed with respect to the power control system 100 according to the fourth embodiment. That is, in the power control system 100 of the present embodiment, the non-insulated boost converter 44 is disposed between the SOFC 10 and the FC isolated converter 14. Other configurations are the same as those of the power control system 100 according to the fourth embodiment.

  In the power control system 100 of the present embodiment having the above configuration, the non-insulated boost converter 44 boosts the output voltage of the SOFC 10 in the low voltage line 22 and outputs it to the intermediate voltage line 38. The FC isolation converter 14 boosts the voltage of the medium voltage line 38 and outputs the boosted voltage to the high voltage line 16. That is, in the present embodiment, the output voltage of the SOFC 10 is boosted in two steps in the order of the non-insulated boost converter 44 and the FC isolated converter 14 and then supplied to the high voltage battery 12.

  In particular, in the present embodiment, the output voltage of the SOFC 10 is adjusted to the non-insulated type while adjusting the auxiliary boost ratio according to the requirements of the high voltage battery 12 according to the control of the non-insulated boost converter 44 in the first stage. The output voltage from the FC isolation converter 14 to the high voltage line 16 can be appropriately adjusted by further boosting the voltage of the medium voltage line 38 boosted by the boost converter 44 by the FC isolation converter 14 in the second stage. it can.

  Also in the present embodiment, as in the fourth embodiment, the total boost ratio in the two-stage boosting of the non-insulated boost converter 44 and the FC isolated converter 14 in accordance with fluctuations in required power of the high-voltage battery 12 ( (Auxiliary boost ratio × basic boost ratio) can be suitably adjusted by switching control for the non-insulated boost converter 44 having good responsiveness.

  Furthermore, since the power control system 100 of the present embodiment has a configuration in which the SOFC 10 is disposed on the input side of the non-insulated boost converter 44, depending on the magnitude of the output power of the SOFC 10, the SOFC 10 can be configured to increase the non-insulated boost. A situation is assumed in which the current input to the converter 44 is relatively large.

  In this embodiment, the circuit of the non-insulated boost converter 44 is configured as a non-insulated converter in which the insulating transformer 14c is not used. Therefore, non-insulated due to an increase in input current from the SOFC 10 An increase in size of the type boost converter 44 is suppressed.

  More specifically, in the case of a configuration in which current is directly input from the SOFC 10 to the FC isolation converter 14 having the isolation transformer 14c, the component (winding) of the isolation transformer 14c is allowed to allow the input current to increase when the input current increases. And the iron core, etc.) are configured to be large, leading to an increase in the size of the FC insulating converter 14 as a whole.

  On the other hand, the non-insulated boost converter 44 is mainly composed of circuit elements such as an inductor or a capacitor, so that the increase in size of these circuit elements is limited as compared with the FC isolated converter 14 even when the input current increases. Can be. Therefore, by disposing the non-insulated boost converter 44 between the SOFC 10 and the FC isolated converter 14 as in the present embodiment, the size of the entire system including the non-isolated boost converter 44 can be suppressed.

  As a result, even if the SOFC 10 having a relatively large output is arranged in the power control system 100 of the present embodiment, the degree of system size increase with respect to the increase in the input current to the non-insulated boost converter 44 due to the large output Therefore, the SOFC 10 having a higher output can be employed while suppressing an increase in the size of the system.

  FIG. 14 is a flowchart illustrating a control mode of the power control system 100 according to the fifth embodiment. In addition, each step shown in this flowchart is not necessarily limited to the order demonstrated below, and can replace each step in the possible range.

  As illustrated, in step S210, the controller 190 calculates the required charging power of the high voltage battery 12 based on the detected charge amount (or estimated value) of the high voltage battery 12 in the same manner as in the fourth embodiment. .

  In step S320, the controller 190 calculates the required generated power for the SOFC 10 from the calculated required charging power of the high-voltage battery 12. At this time, if there is a required power from the second traveling motor 26, the required power for the second traveling motor 26 is added to the required generated power.

  In step S330, the controller 190 determines the SOFC 10 extraction current correction target value (hereinafter also referred to as “second extraction current target value”) and the medium voltage side based on the calculated required generated power and the low-voltage side voltage detection value Vlowd. Calculate the current target value.

  Here, from the viewpoint of limiting the second extraction current target value so that the voltage of the low voltage line 22 (low voltage Vlow) does not exceed a certain upper limit value while satisfying the charge power requirement of the high voltage battery 12. This is the target value of the calculated extraction current (low-voltage side current Ilow) of the SOFC 10. As described above, when there is a required power (required current) from the second traveling motor 26, the second extracted current target value is a value obtained by subtracting the requested current from the second extracted current target value. Apply.

  Therefore, in this embodiment, the controller 190 calculates the second extraction current target value by the same calculation as the calculation of the first extraction current target value described in the fourth embodiment.

  Furthermore, in step S340, the controller 190 calculates the medium voltage side current target value based on the low voltage side voltage detection value Vlowd, the medium voltage side voltage detection value Vmedd, and the calculated second extraction current target value.

  Here, the intermediate voltage side current target value is calculated from the viewpoint of limiting the voltage of the intermediate voltage line 38 (intermediate voltage side voltage Vmed) so as not to exceed a certain upper limit that is a target of the high voltage safety requirement target component. The target value of the medium voltage side current Imed (corresponding to the output current of the non-insulated boost converter 44).

  Specifically, the controller 190 calculates the supply power P by multiplying the low-voltage side voltage detection value Vlowd by the calculated second extraction current target value. Then, the controller 190 calculates a basic medium voltage side current target value based on the calculated supply power P. Furthermore, the controller 190 sets a value obtained by correcting the basic medium voltage side current target value so that the medium voltage side voltage detection value Vmedd is less than the upper limit voltage Vlim as the medium voltage side voltage target value.

  In step S350, the controller 190 controls the non-insulated boost converter 44 and the FC isolated converter 14 based on the calculated second extraction current target value and medium voltage side current target value.

  Specifically, the controller 190 sets the non-isolated boost converter 44 and the non-isolated boost converter 44 and the low voltage side current detection value Ilowd and the medium voltage side voltage detection value Vmedd so as to approach the first extraction current target value and the medium voltage side current target value, respectively. The FC isolation converter 14 is controlled to adjust the total boost ratio (basic boost ratio + auxiliary boost ratio).

  Therefore, in the present embodiment, both the low-voltage side voltage Vlow and the medium-voltage side voltage Vmed are controlled to be lower than the upper limit voltage Vlim by the above steps, in particular, the processing of steps S330 to S350.

  Here, in the power control system 100 of the present embodiment, the intermediate voltage line 38 and the high voltage line 16 are electrically insulated by the insulation transformer 14 c of the FC insulation converter 14. Therefore, when both the low voltage side voltage Vlow and the medium voltage side voltage Vmed are maintained below the upper limit voltage Vlim, the operation voltages of the medium voltage line 38, the non-insulated boost converter 44, the low voltage line 22, and the SOFC 10 are substantially reduced. It can be less than the upper limit voltage Vlim. That is, the electrical safety of each of these components can be further improved.

  In particular, when the power control system 100 of the present embodiment is mounted on an automobile and the upper limit voltage Vlim is set to a value less than 60 V, the medium voltage line 38, the non-insulated boost converter 44, the low voltage line 22 are set. , And the SOFC 10 can be set to components whose operating voltage is substantially less than 60V, so that they can be removed from the high voltage safety requirement target components already described.

  As a result, when the power control system 100 according to the present embodiment is mounted on an automobile, the vehicle is used for more types of components such as the medium voltage line 38, the non-insulated boost converter 44, the low voltage line 22, and the SOFC 10. It is possible to improve the degree of freedom of arrangement layout.

  Furthermore, in the power control system 100 of the present embodiment, the SOFC 10 may be configured so that the substantial maximum output voltage of the SOFC 10 is less than 60V. Thereby, the low voltage side voltage Vlow and the medium voltage side voltage Vmed are more reliably coupled with the control in which the low voltage side voltage Vmed is maintained below 60V, and the SOFC 10, the low voltage system components including the low voltage line 22, and the medium voltage line 38 are included. Since the medium voltage system components can be maintained below 60 V, the electrical safety of these components can be further enhanced.

  As mentioned above, although each embodiment of the present invention was described, each above-mentioned embodiment showed only a part of application example of the present invention, and limited the technical scope of the present invention to the concrete composition of each above-mentioned embodiment. It is not the purpose.

  For example, the control modes of the FC isolated converter 14 or the non-insulated boost converter 44 described above are merely examples, and various changes can be made. That is, in the control of the FC isolation converters 14-1 and 14-2 of the third embodiment, if the respective output currents can be adjusted according to the output characteristics of the SOFCs 10-1 and 10-2. Instead of parameters such as the high-voltage side voltage Vhigh used for controlling the FC insulation converters 14-1 and 14-2, any parameters may be used as appropriate.

  Similarly, in the control of the FC isolated converter 14 or the non-insulated boost converter 44 in the fourth and fifth embodiments, the low voltage side voltage is supplied to the high voltage battery 12 while supplying the electric power according to the required charging power. If it is possible to control Vlow, or the low-voltage side voltage Vlow and the medium-voltage side voltage Vmed to be lower than the upper limit voltage Vlim, instead of the parameters used in the control of these fourth and fifth embodiments, Alternatively, any parameters may be used as appropriate.

  Further, in each of the above-described embodiments, an example has been described in which the FC insulation converter 14 including the insulation type power converter realizes an insulation function by the insulation transformer 14c.

  On the other hand, instead of the FC isolation converter 14 of each of the above embodiments, energy corresponding to the power to be supplied to the high voltage battery 12 is transferred from the input to the output while maintaining substantial electrical insulation between the input and output. You may use the insulation type power converter provided with the arbitrary structures (circuit element etc.) which can be transmitted.

  That is, an arbitrary configuration such as a circuit element that substitutes for the function of the insulating transformer 14c described in each of the above embodiments is newly found after the filing date as well as the technology that existed before the filing date of the present application. Even the technology is not excluded from the technical scope of the present invention as long as the function of the insulating transformer 14c required by the present invention has already been described.

  In the third embodiment, an example in which two SOFCs 10-1 and 10-2 are provided and the FC insulation converters 14-1 and 14-2 are individually connected to each other has been described. Instead of these embodiments, n (n ≧ 3) SOFCs 10 may be arranged, and n FC insulation converters 14 may be individually connected to the n SOFCs 10. Thereby, the extraction current may be individually controlled according to the output characteristics of the n SOFCs 10.

  Furthermore, a predetermined number of SOFC 10 groups among the n SOFCs 10 may be formed, and one FC isolation converter 14 may be connected to the group to control the extraction current of the SOFC 10 in units of groups. .

  Moreover, you may combine the structure of 1st Embodiment thru | or 5th Embodiment arbitrarily. For example, in the power control system 100 in which the FC insulation converters 14-1 and 14-2 are individually connected to the two SOFCs 10-1 and 10-2 according to the third embodiment, a non-insulated boost converter 44 is provided. Also good.

  More specifically, in the power control system 100 according to the third embodiment, between the SOFC 10-1 (10-2) and the FC insulation converter 14-1 (14-2) or the FC insulation converter 14-1 (14-2). A non-insulated boost converter 44-1 (44-2) (not shown, refer to FIG. 8 and FIG. 11) is provided between the high-voltage battery 12 and the FC isolated converter 14-1 (14-2) and the non-insulated type The control described in the fourth embodiment and the fifth embodiment may be executed on the boost converter 44-1 (44-2).

  Moreover, you may apply control of 3rd Embodiment thru | or 5th Embodiment when the FC insulation converter 14 is driving in 1st Embodiment or 2nd Embodiment.

  Furthermore, in the fourth and fifth embodiments, the insulating transformer 14c of the FC insulating converter 14 may be used only for an electrical insulating function and not boosted by the number of turns. That is, an element other than the insulation transformer 14c in the FC insulation converter 14 is set after the step-up ratio by the insulation transformer 14c is set to 1: 1 by making the number of turns of the primary side coil and the number of turns of the secondary side coil equal. The booster circuit may be configured to boost the output voltage of the SOFC 10 by the non-insulated boost converter 44.

  In each of the above embodiments, the example in which the power generation device is the SOFC 10 has been described. However, other power generation devices such as an internal combustion engine and an alternator may be employed. Furthermore, the power control system 100 of each of the above embodiments includes an arbitrary vehicle having an external load (motor) that is driven by power supplied from a railway vehicle or the like other than an automobile, or an external load driven by other power. It can be applied to the provided apparatus.

10 SOFC
12 High Voltage Battery 14 FC Insulated Converter 20 First Travel Motor 26 Second Travel Motor 100 Power Control System

Claims (9)

A power generator for generating low voltage power;
A high voltage battery charged with power generated by the power generation device;
A first external load receiving power from the high voltage battery;
A power converter connected between the power generation device and the high voltage battery;
A second external load that receives power from the power generation device,
The power control system, wherein the power converter includes an isolated power converter. The power control system according to claim 1,
A power control system in which a rated output of the first external load is larger than a rated output of the second external load. The power control system according to claim 1 or 2,
Electric power is supplied from the high voltage battery to the first external load, electric power is supplied from the electric power generation device to the second external load, and electric power generated by the electric power generation device is passed through the electric power converter. A power control system for supplying power to the first external load as auxiliary power. The power control system according to claim 1 or 2,
Supplying power from the high voltage battery to the first external load;
Supplying power from the power generation device to the second external load;
A power control system for stopping the power converter. The power control system according to claim 1 or 2,
Supplying power from the power generation device to the second external load;
A power control system for stopping the power converter. The power control system according to claim 1 or 2,
A power control system for supplying regenerative power from the second external load as power for charging the high-voltage battery via the power converter. The power control system according to any one of claims 1 to 6,
A third external load connected in parallel with the second external load;
The power generation device is a power control system that supplies power to the second external load and the third external load. The power control system according to any one of claims 1 to 7,
The power generation device is configured to take a maximum output voltage that is less than a predetermined voltage that is a criterion for determining a high-voltage safety requirement target component to which a predetermined safety requirement is imposed in a device in which the power control system is mounted. ,
Power control system. The power control system according to claim 8,
The power generation device is configured such that the maximum output voltage is less than 60V.
Power control system.

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