WO2022009984A1 - Conversion device - Google Patents

Abstract

A conversion device (10) is used in a power supply system in which a plurality of batteries (34A, 34B) may be connected at least in parallel. The conversion device (10) includes a power conversion unit (40). The power conversion unit (40) performs a first conversion operation of converting power inputted from the batteries (34A, 34B) and outputting power to a conductive path different from the batteries (34A, 34B). The power conversion unit (40) performs a second conversion operation of outputting power individually to at least any of the batteries (34A, 34B).

Description

Converter

This disclosure relates to a conversion device.

Patent Document 1 discloses a battery control device mounted on an electric vehicle. In the battery control device disclosed in Patent Document 1, a plurality of batteries are connected in parallel when the electric vehicle is running, and a plurality of batteries are connected in series when the plurality of batteries are charged by the external power feeding device.

Japanese Unexamined Patent Publication No. 2018-85790

In the system disclosed in Patent Document 1, there is a concern that a state imbalance may occur between one of the batteries and the other battery. Therefore, in this type of system, a technique that easily corrects the imbalance of a plurality of batteries is applied. It is hoped that it will be done.

The present disclosure provides a conversion device that can easily correct the imbalance of a plurality of batteries.

The conversion device, which is one of the present disclosures, is
A converter used in power systems where multiple batteries can be connected at least in parallel.
It has a power conversion unit that performs a first conversion operation that converts the power input from each of the batteries and outputs the power to a conductive path different from that of the battery.
The power conversion unit performs a second conversion operation of individually outputting power to at least one of the batteries.

The conversion device, which is one of the present disclosures, can easily correct the imbalance of a plurality of batteries.

FIG. 1 is a block diagram schematically illustrating an in-vehicle system including the conversion device according to the first embodiment of the present disclosure. FIG. 2 is a schematic diagram schematically illustrating a vehicle equipped with the in-vehicle system of FIG. FIG. 3 is a circuit diagram illustrating a specific configuration of a part of the power conversion unit in the in-vehicle system of FIG. FIG. 4 is a block diagram showing a part of the in-vehicle system of FIG. 1 embodied and a part omitted. FIG. 5 is an explanatory diagram illustrating an example of operation in the first mode in the in-vehicle system of FIG. FIG. 6 is an explanatory diagram illustrating an example of operation in the second mode in the in-vehicle system of FIG. FIG. 7 is an explanatory diagram illustrating an example of operation in the third mode in the in-vehicle system of FIG. FIG. 8 is an explanatory diagram illustrating an example of operation in the fourth mode in the in-vehicle system of FIG. FIG. 9 is a block diagram showing a part of the in-vehicle system including the conversion device of the second embodiment, with a part thereof being embodied and a part omitted. FIG. 10 is a circuit diagram illustrating a specific configuration of a part of the power conversion unit in the in-vehicle system of FIG. FIG. 11 is an explanatory diagram illustrating an example of operation in the first mode in the in-vehicle system of FIG. FIG. 12 is an explanatory diagram illustrating an example of operation in the second mode in the in-vehicle system of FIG. FIG. 13 is an explanatory diagram illustrating an example of operation in the third mode in the in-vehicle system of FIG. FIG. 14 is a block diagram schematically illustrating an in-vehicle system including the conversion device of the third embodiment. FIG. 15 is a circuit diagram showing a part of the conversion device of the third embodiment embodied and a part omitted. FIG. 16 is a circuit diagram showing a part of the conversion device of the fourth embodiment embodied and a part omitted.

In the following, the embodiments of the present disclosure are listed and exemplified. The features [1] to [27] exemplified below may be combined in any way within a consistent range.

[1] A converter used in a power supply system in which a plurality of batteries can be connected at least in parallel.
It has a power conversion unit that performs a first conversion operation that converts the power input from each of the batteries and outputs the power to a conductive path different from that of the battery.
The power conversion unit is a conversion device that performs a second conversion operation that individually outputs power to at least one of the batteries.

In the conversion device of the above [1], the power conversion unit not only performs the first conversion operation of performing power conversion by using the power supplied from each battery as an input, but also individually supplies power to at least one of the batteries. The second conversion operation to output can also be performed. Therefore, this conversion device is easier to correct the imbalance of a plurality of batteries than the device that can realize only the first conversion operation.

The conversion device of [2] has the following features in the conversion device according to the above [1]. The power conversion unit includes a plurality of converters. Each of the above converters is provided corresponding to each of the above batteries. At least one of the plurality of converters performs power conversion in both directions.

In the conversion device of the above [2], since each converter is provided corresponding to each battery, it is possible to realize a configuration that makes it easy to correct the imbalance of a plurality of batteries, and to achieve redundancy by a plurality of converters. ..

The conversion device of [3] has the following features in the conversion device described in [2] above. The first power conversion unit outputs power to the conductive path based on the power supplied from one battery by at least one of the converters in response to a partial charging instruction from the outside. The conversion operation is performed, and the second conversion operation is performed so that the other converter outputs power to the other battery based on the power supplied from the conductive path.

The conversion device of the above [3] supplies electric power to the conductive path by the electric power conversion of one converter based on the electric power of one battery, and charges another battery by the electric power conversion of another converter using this electric power. be able to. Therefore, this converter can correct the imbalance of a plurality of batteries more quickly.

The conversion device of [4] has the following features in the conversion device according to the above [2] or [3]. The conductive path is electrically connected to a second battery different from the plurality of batteries. The power conversion unit stops the conversion operation of one converter in response to a partial stop instruction from the outside, and the other converter is based on the power supplied from the second battery to the other battery. The second conversion operation is performed so as to output electric power to.

The conversion device of the above [4] can supply power to the other battery side by giving priority to the power supply from the second battery over the power supply from one battery.

The conversion device of [5] has the following features in the conversion device according to any one of the above [2] to [4]. The power conversion unit has a plurality of cutoff units. Each of the above-mentioned cutoff portions is provided between each of the above-mentioned converters and the above-mentioned conductive path. The cutoff portion allows electric power to be transmitted between the converter and the conductive path via itself when it is in the on state, and between the converter and the conductive path via itself when it is in the off state. Blocks the transmission of power.

In the conversion device of the above [5], since each cutoff portion is provided between each of the converters and the conductive path, each converter and the conductive path are individually cut off as necessary. be able to.

The conversion device of [6] has the following features in the conversion device according to [5] above. The conversion device of [6] includes a cutoff control unit that controls a plurality of the above-mentioned cutoff units, a converter control unit that controls the plurality of the above-mentioned converters, and a failure detection unit that detects a failure of each of the plurality of the above-mentioned converters. Have. When the failure detection unit detects a failure of any of the converters, the cutoff control unit turns off the cutoff unit provided between the converter where the failure is detected and the conductive path. Switch. When the failure detection unit detects a failure of any of the converters, the converter control unit operates the converter in which the failure is not detected.

When any of the converters in the above-mentioned [6] fails, the converter can individually cut off between the failed converter and the conductive path, and electrically disconnect the failed converter from the conductive path. can. Then, this conversion device can continue the power conversion by operating the converter in which the failure has not occurred while suppressing the influence of the converter in which the failure has occurred.

The conversion device of [7] has the following features in the conversion device according to any one of the above [2] to [6]. The plurality of batteries include a first battery unit and a second battery unit. The plurality of converters include a first converter and a second converter. Between the first battery unit and the first converter, a first wiring unit and a second wiring unit, which are paths to which a voltage based on the voltage across the first battery unit is applied, are provided. Between the second battery unit and the second converter, a third wiring unit and a fourth wiring unit, which are paths to which a voltage based on the voltage across the second battery unit is applied, are provided. The first converter performs an operation of converting a voltage applied between the first wiring unit and the second wiring unit and applying an output voltage to the conductive path. The second converter performs an operation of converting a voltage applied between the third wiring portion and the fourth wiring portion and applying an output voltage to the conductive path. Further, the conversion device of [7] includes a first relay unit that switches between an on state that permits energization between the first wiring unit and the third wiring unit and an off state that cuts off the energization. Further, the conversion device of [7] has a second relay unit that switches between an on state that permits energization between the second wiring unit and the fourth wiring unit and an off state that cuts off the energization.

In the conversion device of the above [7], when the first relay unit and the second relay unit are in the ON state, not only the first battery unit but also the second battery unit with respect to the first wiring unit and the second wiring unit. Is also powered. Further, when the first relay unit and the second relay unit are in the ON state, electric power is supplied to the third wiring unit and the fourth wiring unit not only from the first battery unit but also from the second battery unit. Therefore, both the first converter and the second converter can perform power conversion based on the power from both battery units. On the other hand, when the first relay unit and the second relay unit are in the off state, the space between the first wiring unit and the third wiring unit is cut off, and the space between the second wiring unit and the fourth wiring unit is cut off. Therefore, the second converter can operate independently while suppressing the influence of the first battery unit, and the first converter can operate independently while suppressing the influence of the second battery unit.

The conversion device of [8] has the following features in the conversion device according to the above [1]. The power conversion unit includes a plurality of first conversion units, a transformer, and a second conversion unit. The transformer includes a plurality of first coils and a second coil, and the plurality of the first coils and the second coil are magnetically coupled. Each of the first coils is provided corresponding to each of the first conversion units. Each of the first conversion units converts DC power based on the power from each of the batteries and outputs AC power to each of the first coils. At least one of the first conversion units performs power conversion in both directions.

The conversion device of the above [8] can realize a configuration that easily corrects the imbalance of a plurality of batteries by a configuration in which the conversion unit is integrated.

The conversion device of [9] has the following features in the conversion device according to the above [8]. The power conversion unit performs power conversion by a plurality of the first conversion units and the transformer based on the power supplied from at least one of the batteries in response to a partial charge instruction from the outside, and the other The second conversion operation is performed so as to supply electric power to the battery.

The conversion device of the above [9] can perform a conversion operation of supplying power to another battery based on the power supplied from one battery while suppressing the operation of the second conversion unit, thereby further improving efficiency. Can be enhanced.

The conversion device of [10] has the following features in the conversion device according to the above [8] or [9]. The conductive path is electrically connected to a second battery different from the plurality of batteries. The power conversion unit, in response to a partial stop instruction from the outside, stops the conversion operation of one of the first conversion units corresponding to any one of the above batteries, while the other power conversion unit corresponds to the other battery. The second conversion operation is performed so that the first conversion unit, the transformer, and the second conversion unit output electric power to the other batteries based on the electric power supplied from the second battery.

The conversion device of the above [10] can supply power to the other battery side by giving priority to the power supply from the second battery over the power supply from one battery.

The conversion device of [11] has the following features in the conversion device according to any one of [8] to [10]. The plurality of batteries include a first battery unit and a second battery unit. The plurality of first conversion units include one of the first conversion units and the other first conversion unit. Between the first battery unit and one of the first conversion units, a first wiring unit and a second wiring unit, which are paths to which a voltage based on the voltage across the first battery unit is applied, are provided. Between the second battery unit and the other first conversion unit, a third wiring unit and a fourth wiring unit, which are paths to which a voltage based on the voltage across the second battery unit is applied, are provided. The first conversion unit performs an operation of converting a voltage applied between the first wiring unit and the second wiring unit to generate an AC voltage in the first coil. The other first conversion unit performs an operation of converting the voltage applied between the third wiring unit and the fourth wiring unit to generate an AC voltage in the other first coil. Further, the conversion device of [11] has a first relay unit that switches between an on state that permits energization between the first wiring unit and the third wiring unit and an off state that cuts off the energization, and the second relay unit. It has a second relay unit that switches between an on state that permits energization and an off state that cuts off energization between the wiring unit and the fourth wiring unit.

In the conversion device of the above [11], when the first relay unit and the second relay unit are in the ON state, not only the first battery unit but also the second battery unit with respect to the first wiring unit and the second wiring unit. Is also powered. Further, when the first relay unit and the second relay unit are in the ON state, electric power is supplied to the third wiring unit and the fourth wiring unit not only from the first battery unit but also from the second battery unit. Therefore, any one of the first conversion unit and the other first conversion unit can perform power conversion based on the power from both battery units. On the other hand, when the first relay unit and the second relay unit are in the off state, the space between the first wiring unit and the third wiring unit is cut off, and the space between the second wiring unit and the fourth wiring unit is cut off. Therefore, the influence of the first battery unit can be suppressed and the other first conversion unit can operate independently, and the influence of the second battery unit can be suppressed and the first conversion unit can operate independently. can.

The conversion device of [12] has the following features in the conversion device according to any one of [7] and [11]. The conversion device of [12] includes a relay control unit that controls the first relay unit and the second relay unit, an abnormality in power supply from the first battery unit, and an abnormality in power supply from the second battery unit. It has an abnormality detection unit for detecting. When the abnormality detection unit detects an abnormality in the power supply from either the first battery unit or the second battery unit, the relay control unit sets the first relay unit and the second relay unit. Switch to the off state.

The conversion device of the above [12] switches the first relay unit and the second relay unit to the off state when the power supply from any of the battery units is abnormal, and the first relay unit and the second relay unit. It is possible to cut off the energization through the unit. Therefore, in this case, the first converter and the second converter are electrically separated in the circuit on the battery part side, and the influence of the battery part in which the abnormality occurs is suppressed from affecting both the first converter and the second converter. be able to.

The conversion device of [13] has the following features in the conversion device according to any one of [1] to [12]. The conductive path is electrically connected to a second battery different from the plurality of batteries. When a predetermined condition is satisfied, the power conversion unit performs power conversion based on the power from the second battery, and outputs the power individually to at least one of the batteries. Do the action.

The conversion device of the above [13] can correct the imbalance of a plurality of batteries by utilizing the electric power from the second battery.

The conversion device of [14] has the following features in the conversion device according to any one of [1] to [13]. The conversion device includes a control unit that controls the power conversion unit. When a predetermined start condition is satisfied, the control unit causes the power conversion unit to perform an operation of reducing the difference between the output voltages of the plurality of batteries or the SOC (State Of Charge).

The conversion device of the above [14] can operate the power conversion unit so as to reduce the difference between the output voltages or SOCs of a plurality of batteries when the start condition is satisfied.

[15] In the conversion device according to any one of the above [1] to [14], the power supply system is a system in which a plurality of the batteries are switched between series connection and parallel connection.

In the above conversion device [15], it is easy to correct the imbalance of a plurality of batteries in a system in which a plurality of batteries are switched between a series connection and a parallel connection.

[16] In the conversion device according to any one of the above [1] to [14], the power supply system is a system in which a plurality of the above batteries are connected in parallel and does not switch to the series connection.

In the above conversion device [16], it is easy to correct the imbalance of a plurality of batteries in a system in which a plurality of batteries are maintained in parallel connection.

[17] The conversion device according to any one of the above [1] to [15] further has the following features. The conversion device of [17] includes a control unit that controls the power conversion unit, a switching circuit, and a switching control unit that controls the switching circuit. The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system. The switching circuit switches between a state in which a plurality of the batteries are connected in series between the pair of power paths and a state in which the plurality of batteries are connected in parallel. In a state where the switching control unit controls the switching circuit so as to supply power to the load from the plurality of batteries connected in series while connecting the plurality of batteries in series between the pair of power paths. The control unit causes the power conversion unit to perform at least one of the first conversion operation and the second conversion operation.

The conversion device of [17] can supply a load with a plurality of batteries connected in series, and can adjust the power of the plurality of high-voltage batteries in that state.

[18] The conversion device according to any one of the above [1] to [15] and [17] further has the following features. The conversion device of [18] includes a switching circuit and a switching control unit that controls the switching circuit. The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system. The switching circuit switches between a state in which a plurality of the batteries are connected in series between the pair of power paths and a state in which the plurality of batteries are connected in parallel. The switching control unit controls the switching circuit so as to switch between a state in which a plurality of the batteries are connected in series between the pair of electric power paths and a state in which the plurality of batteries are connected in parallel while the vehicle is traveling.

The conversion device of [18] can switch the series-parallel of a plurality of batteries while the vehicle is running, and in such a case, it is possible to add a function that easily corrects the imbalance of the plurality of batteries.

[19] The conversion device according to the above [18] further has the following features. The switching control unit switches a plurality of the batteries into a series connection state and a parallel connection state according to the traveling state of the vehicle while the vehicle is traveling.

The conversion device of [19] can switch the series-parallel of a plurality of batteries according to the traveling state while the vehicle is traveling, and in such a case, adds a function of easily correcting the imbalance of the plurality of batteries. be able to.

[20] The conversion device according to the above [17] further has the following features. The switching control unit switches between a state in which a plurality of the batteries are connected in series between the pair of electric power paths and a state in which the batteries are connected in parallel, depending on the traveling state of the vehicle while the vehicle is traveling. The control unit causes the power conversion unit to perform at least one of the first conversion operation and the second conversion operation when at least a plurality of the batteries are connected in series while the vehicle is running.

The conversion device of [20] can switch the series-parallel of a plurality of batteries according to the traveling state while the vehicle is traveling, and in such a case, adds a function of easily correcting the imbalance of the plurality of batteries. be able to. Moreover, since at least one of the first conversion operation and the second conversion operation can be performed when the batteries are connected in series according to the traveling state, the series and parallel can be switched according to the traveling state. It will be easier to correct the imbalance earlier for the battery.

[21] The conversion device according to any one of the above [1] to [20] further has the following features. The conversion device of [21] includes a switching circuit, a switching control unit that controls the switching circuit, and an abnormality detecting unit that detects a battery in which an abnormality in power supply has occurred from among the plurality of the batteries. The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system. The switching circuit switches between a state in which a part of the plurality of batteries is connected between the pair of power paths and a state in which the plurality of batteries are connected in parallel between the pair of power paths. When the abnormality of the power supply of any of the batteries is detected by the abnormality detection unit, the switching control unit puts the battery in which the abnormality of the power supply is not detected between the pair of power paths. Connecting.

The conversion device of [21] can have both a function of correcting an imbalance of a plurality of batteries and a function of detecting the failure of each of the plurality of batteries. Then, when a failure of any of the batteries is detected, power can be supplied to the load from a normal battery in which the failure is not detected.

[22] The conversion device according to the above [21] further has the following features. The switching control unit can connect a plurality of the batteries in parallel between the pair of electric power paths while the vehicle is running, and the switching control unit can connect any of the batteries while the vehicle is running. When the abnormality of the power supply of the battery is detected by the abnormality detection unit, the battery in which the abnormality of the power supply is not detected is connected between the pair of power paths.

The conversion device of [22] can operate the load while connecting a plurality of batteries in parallel while driving, and further, since the function of correcting the imbalance of the batteries is added, the load is applied in the parallel connection state. When supplying electric power, it is possible to make it difficult to generate a circulating current. Moreover, if any battery failure is detected during driving, the load can be operated by a normal battery in which no failure is detected, so that the circulating current is suppressed and the battery is lost while driving. It is possible to achieve both countermeasures against the fall.

The conversion device of [23] has the following features in the conversion device according to any one of [1] to [22]. In the case of receiving a partial charging instruction from the outside, the power conversion unit performs the first conversion so as to supply power to the conductive path based on the power from any one of the batteries in the case of the first condition. The operation is performed, and the second conversion operation is performed so as to supply electric power to the other batteries based on the electric power from the conductive path. Then, the electric power based on the electric power supplied from the electric power conversion unit to the conductive path is supplied to the load or the second battery electrically connected to the conductive path.

In the conversion device of the above [23], when the power conversion unit receives a partial charge instruction from the outside and in the first condition, the load or the second is performed by power conversion using the power from one battery as an input. It is possible to supply power to a battery and charge another battery in parallel.

The conversion device of [24] has the following features in the conversion device according to any one of [1] to [23]. In the case of receiving a partial charging instruction from the outside, the power conversion unit performs the first conversion so as to supply power to the conductive path based on the power from any one of the batteries under the second condition. It operates and converts the input power based on the power supplied from the power conversion unit to the conductive path and the power from the second battery electrically connected to the conductive path to transfer the power to the other batteries. The second conversion operation is performed so as to supply.

The above-mentioned conversion device [24] inputs this power while securing a larger amount of power supplied to the conductive path when the power conversion unit receives a partial charging instruction from the outside and in the second condition. By the power conversion, it is possible to supply power to another battery.

The conversion device of [25] is the conversion device according to any one of the above [2] to [7], or the above-mentioned [12] to the above-mentioned conversion device according to any one of [24]. The conversion device quoting any of the above [7] from 2] has the following features. The converter has one converter, a transformer, and another converter. The transformer includes a primary coil and a secondary coil that are magnetically coupled to each other. The one conversion unit converts the DC voltage applied between the pair of one-side conductive paths corresponding to the battery based on the power from the battery corresponding to the one conversion unit into an AC voltage, and the primary conversion unit. The first operation of generating an AC voltage in the side coil and the second operation of converting the AC voltage generated in the primary side coil into a DC voltage and applying the DC voltage between the pair of one-side conductive paths. conduct. The other conversion unit has a third operation of converting the AC voltage generated in the secondary side coil into a DC voltage and applying the DC voltage between the pair of other side conductive paths corresponding to the other conversion units. The fourth operation of converting the DC voltage applied between the pair of other-side conductive paths to generate an AC voltage in the secondary-side coil is performed.

In the above-mentioned conversion device [25], each of the plurality of converters is composed of an isolated converter, and the power conversion can be performed bidirectionally between the storage unit and the conductive path corresponding to each converter. ..

The conversion device of [26] has the following features in the conversion device according to the above [25]. In the plurality of converters, the primary coil and the secondary coil in the transformer of one converter and the primary coil and the secondary coil in the transformer of another converter are magnetically coupled.

The above-mentioned conversion device [26] can increase the degree of freedom of power conversion in one converter and another converter.

The conversion device of [27] has the following features in the conversion device according to the above [26]. The conversion device of [27] has a converter control unit that controls a plurality of the above converters. The converter control unit is applied to one of the converters of the converter and the other converter in a state where the operation of the converter of the converter and the other converter of the other converter is stopped. While performing the first operation, conversion control is performed so that the other conversion unit performs the second operation.

In the above-mentioned conversion device [27], in correcting the imbalance of a plurality of batteries via the plurality of converters, one converter and the other conversion unit of each of the other converters are stopped. The other battery can be charged based on the power from one of the batteries.

<First Embodiment>
(Overview of in-vehicle system)
FIG. 1 shows a conversion device 10 according to the first embodiment of the present disclosure. As shown in FIG. 2, the conversion device 10 is a device used as a part of the in-vehicle system 2 mounted on the vehicle 1. The vehicle 1 is a vehicle equipped with a conversion device 10, and is, for example, a vehicle such as a PHEV (Plug-in Hybrid Electric Vehicle) or an EV (Electric Vehicle).

As shown in FIG. 2, the in-vehicle system 2 includes a power supply system 3, a drive unit 4, a high voltage load 5, a low voltage load 8, and the like. The power supply system 3 includes a conversion device 10, a low voltage battery 32, and a high voltage battery 34.

The drive unit 4 includes an inverter 7 and a motor 6. The inverter 7 generates AC power (for example, three-phase AC) from DC power based on the power supplied from the high-voltage battery 34, and supplies it to the motor 6. The motor 6 is, for example, a main engine system motor. The motor 6 is a device that rotates based on the electric power supplied from the high-voltage battery 34 and applies a rotational force to the wheels of the vehicle 1.

The high-voltage load 5 is a load that can operate by receiving power supplied from the high-voltage battery 34. The high-voltage load 5 is, for example, an air conditioner, a heater, or the like, and may be an electric device other than these.

The low voltage load 8 is, for example, an accessory device necessary for operating an engine and a motor. This accessory is, for example, a starter motor, an alternator, a radiator cooling fan, and the like. The low voltage load 8 may include an electric power steering system, an electric parking brake, lighting, a wiper drive unit, a navigation device, and the like.

In the present specification, the state in which the vehicle is running includes the state in which the vehicle 1 is moving, but is not limited to the state in which the vehicle 1 is moving. When the vehicle is running, the vehicle 1 moves when the accelerator is stepped on. When the vehicle is running, it includes a state in which the vehicle 1 is stopped without moving and power is supplied to any or all of the low voltage loads 8. If the vehicle 1 is a PHEV, the idling state of the engine is also included when the vehicle is running.

The power supply system 3 is a system in which a plurality of batteries 34A and 34B are switched between series connection and parallel connection. The power supply system 3 includes a low voltage battery 32, a high voltage battery 34, and a conversion device 10.

The power supply system 3 can charge the high voltage battery 34 and the low voltage battery 32 based on the AC power supplied from the external AC power source when the external AC power source (not shown) is connected to the vehicle 1. The vehicle 1 has a connection terminal (not shown) to which an external AC power supply is connected, and an external AC power supply (not shown) may be connected to the connection terminal.

In the power supply system 3, when a quick charger is connected to the connection terminal of the vehicle 1 and a voltage exceeding the voltage specifications of the batteries 34A and 34B (for example, 800V) is supplied from the quick charger, a circuit (not shown) is used. A DC voltage (for example, 800V) exceeding the voltage specifications of the batteries 34A and 34B is applied between the terminals 9A and 9B. In this case, the control unit 18 can control the switch unit 14 to directly connect the first high voltage battery 34A and the second high voltage battery 34B.

On the other hand, in the power supply system 3, when a quick charger is connected to the connection terminal of the vehicle 1 and a voltage (for example, 400 V) corresponding to the voltage specifications of the batteries 34A and 34B is supplied from the quick charger, it is not shown. A DC voltage (for example, 400V) suitable for the voltage specifications of the batteries 34A and 34B is applied between the terminals 9A and 9B via the circuit. In this case, the control unit 18 can control the switch unit 14 to connect the first high voltage battery 34A and the second high voltage battery 34B in parallel.

The power path 28A is electrically connected to the terminal 9A via the switch 26A. The switch 26A switches between the conduction state and the cutoff state between the terminal 9A and the power path 28A. The terminal 9B is electrically connected to the power path 28B via the switch 26B. The switch 26B switches between the continuity state and the cutoff state between the terminal 9B and the power path 28B. The switches 26A and 26B may be semiconductor relays or mechanical relays. The power path 28A is electrically connected to the electrode having the highest potential in the first high voltage battery 34A, and is, for example, the same potential as this electrode. The power path 28B is electrically connected to the electrode having the lowest potential in the second high voltage battery 34B, and is, for example, the same potential as this electrode. The power paths 28A and 28B are paths for supplying electric power from the high-voltage battery 34 to the inverter 7. The power path 28A is provided with a relay 93 that switches the power path 28A between an energizable state and an energization cutoff state. When the relay 93 is in the off state, the energization of the power path 28A is cut off. A relay 94 and a fuse 97 are provided in the power path 28B. The fuse 97 cuts off the energization of the power path 28B when an excessive current flows through the power path 28B. Further, a series component in which the relay 95 and the resistor 96 are provided in series is connected in parallel to the relay 94. When the relay 94 is in the off state, a current flows through the series component, and when the relays 94 and 95 are in the off state, the energization of the power path 28B is cut off. The relays 93, 94, 95 may be a semiconductor relay or a mechanical relay.

The high-voltage battery 34 includes a plurality of batteries, specifically, a first high-voltage battery 34A and a second high-voltage battery 34B. The first high voltage battery 34A and the second high voltage battery 34B both correspond to an example of a battery. The first high voltage battery 34A corresponds to an example of the first battery unit. The second high voltage battery 34B corresponds to an example of the second battery unit. The high-voltage battery 34 is a power source in which the first high-voltage battery 34A and the second high-voltage battery 34B are switched between series connection and parallel connection by a switching operation by the switch unit 14 described later. The high-voltage battery 34 is configured to be rechargeable and dischargeable. The high voltage battery 34 outputs a high voltage (for example, about 300 V) for driving the drive unit 4. The output voltage of each of the first high-voltage battery 34A and the second high-voltage battery 34B when fully charged is higher than the output voltage of the low-voltage battery 32 when fully charged. The first high-voltage battery 34A and the second high-voltage battery 34B may be composed of a lithium ion battery or may be composed of other types of storage batteries.

The low voltage battery 32 corresponds to an example of a power storage unit. The low voltage battery 32 is configured to be rechargeable and dischargeable. The low voltage battery 32 supplies power to the low voltage load 8. The low voltage battery 32 may be composed of a lead storage battery or another type of storage battery. The low voltage battery 32 outputs a predetermined voltage (for example, 12V) when fully charged.

(Configuration of converter)
As shown in FIG. 1, the conversion device 10 mainly includes a power control device 12 and a switch unit 14.

The switch unit 14 includes a plurality of switches 14A, 14B, 14C. The plurality of switches 14A, 14B, 14C may be a semiconductor relay or a mechanical relay. The switch unit 14 is a switching circuit for switching the first high-voltage battery 34A and the second high-voltage battery 34B between series connection and parallel connection. The switch unit 14 connects the first high-voltage battery 34A and the second high-voltage battery 34B in series when the switch 14B is in the on state and the switches 14A and 14C are in the off state. The switch unit 14 connects the first high-voltage battery 34A and the second high-voltage battery 34B in parallel when the switch 14B is in the off state and the switches 14A and 14C are in the on state. The switch unit 14 is controlled by the control unit 18. The control unit 18 controls the switching of the switch unit 14. The control unit 18 may at least control the switch 14B to be in the on state and the switches 14A and 14C to be in the off state and the switch 14B to be in the off state and the switches 14A and 14C to be in the on state.

The power control device 12 is a device capable of performing power conversion by inputting power supplied from the high voltage battery 34 or the low voltage battery 32. The power control device 12 mainly includes a power conversion unit 40, a management device 17, and a control unit 18.

The control unit 18 is a device that performs various controls on the devices in the in-vehicle system 2. The control unit 18 has a calculation function, an information processing function, a storage function, and the like. The control unit 18 may be configured by a plurality of electronic control devices, or may be configured by a single electronic control device. The control unit 18 controls, for example, the power conversion unit 40. Specific examples of control of the power conversion unit 40 by the control unit 18 will be described in detail later.

The management device 17 has a function of monitoring the high voltage battery 34. The management device 17 continuously detects the output voltage and SOC (State Of Charge) of each of the plurality of batteries (first high-voltage battery 34A and second high-voltage battery 34B) constituting the high-voltage battery 34.

The power conversion unit 40 converts the power input from each battery (each of the first high voltage battery 34A and the second high voltage battery 34B), and the third conductive path different from the first high voltage battery 34A and the second high voltage battery 34B. The first conversion operation of outputting power to 23A and 23B is performed. The third conductive paths 23A and 23B correspond to an example of the conductive paths. The power conversion unit 40 includes a first power conversion unit 50 and a second power conversion unit 60. Both the first power conversion unit 50 and the second power conversion unit 60 correspond to an example of a converter. The first power conversion unit 50 corresponds to an example of the first converter. The second power conversion unit 60 corresponds to an example of the second converter. Each of these plurality of converters (first power conversion unit 50 and second power conversion unit 60) is provided corresponding to each of the plurality of batteries (first high voltage battery 34A and second high voltage battery 34B). Specifically, the output voltage of each battery is applied between each pair of conductive paths, which are input / output paths on one side of each converter. For example, it corresponds to the first high voltage battery 34A so that the output voltage of the first high voltage battery 34A is applied between the pair of first conductive paths 21A and 21B which are input / output paths on one side of the first power conversion unit 50. The first power conversion unit 50 is provided. Further, it corresponds to the second high voltage battery 34B so that the output voltage of the second high voltage battery 34B is applied between the pair of second conductive paths 22A and 22B which are the input / output on one side of the second power conversion unit 60. A second power conversion unit 60 is provided. Each of the first power conversion unit 50 and the second power conversion unit 60 performs power conversion in both directions. The first conductive path 21A corresponds to an example of the first wiring portion. The first conductive path 21B corresponds to an example of the second wiring portion. The second conductive path 22A corresponds to an example of the third wiring portion. The second conductive path 22B corresponds to an example of the fourth wiring portion.

A cutoff unit 91 is provided between the first power conversion unit 50 and the third conductive path 23A. The cutoff unit 91 is configured as a known relay. When the cutoff unit 91 is on, bidirectional energization via the cutoff unit 91 is allowed, and when the cutoff unit 91 is off, bidirectional energization via the cutoff unit 91 is cut off. A blocking unit 92 is provided between the second power conversion unit 60 and the third conductive path 23A. When the cutoff unit 92 is on, bidirectional energization via the cutoff unit 92 is allowed, and when the cutoff unit 92 is off, bidirectional energization via the cutoff unit 92 is cut off. The cutoff units 91 and 92 may be semiconductor relays (for example, butt-type relays in which two FETs are arranged in opposite directions as in the third embodiment), or may be mechanical relays.

The first power conversion unit 50 functions as a bidirectional DCDC converter. The first power conversion unit 50 may perform a step-down operation so as to step down the DC voltage applied between the first conductive paths 21A and 21B and apply a DC voltage between the third conductive paths 23A and 23B. The first power conversion unit 50 may perform a boosting operation so as to boost the DC voltage applied between the third conductive paths 23A and 23B and apply the DC voltage between the first conductive paths 21A and 21B. The circuit configuration of the first power conversion unit 50 is not particularly limited as long as it functions as a bidirectional DCDC converter, but in a typical example of the conversion device 10 described below, a circuit as shown in FIG. 3 is adopted. Has been done. In the example of FIG. 3, the first power conversion unit 50 is configured as an isolated bidirectional DCDC converter. The first power conversion unit 50 includes a first conversion circuit 51, a transformer 53, and a second conversion circuit 52.

The first conversion circuit 51 corresponds to an example of one conversion unit. The first conversion circuit 51 has a function of converting DC power and AC power in both directions. The first conversion circuit 51 has a function of converting the DC voltage applied between the first conductive paths 21A and 21B to generate an AC voltage in the first coil 53A (first operation). The first conversion circuit 51 also has a function of converting an AC voltage generated in the first coil 53A and outputting a DC voltage between the first conductive paths 21A and 21B (second operation). The first conversion circuit 51 includes a capacitor 51A and switch elements 51C, 51D, 51E, 51F constituting a full bridge circuit. The transformer 53 includes a first coil 53A connected to the first conversion circuit 51 and a second coil 53B connected to the second conversion circuit 52. The first coil 53A and the second coil 53B are magnetically coupled. The second conversion circuit 52 corresponds to an example of another conversion unit. The first coil 53A corresponds to an example of the primary coil. The second coil 53B corresponds to an example of the secondary coil. The second conversion circuit 52 has a function of converting AC power and DC power in both directions. The second conversion circuit 52 has a function of converting an AC voltage generated in the second coil 53B and outputting a DC voltage between the third conductive paths 23A and 23B (third operation). The second conversion circuit 52 also has a function of converting the DC voltage applied between the third conductive paths 23A and 23B to generate an AC voltage in the second coil 53B (fourth operation). The second conversion circuit 52 includes switch elements 52C, 52D, an inductor 52E, a capacitor 52A, and the like.

The second power conversion unit 60 functions as a bidirectional DCDC converter. The second power conversion unit 60 may perform a step-down operation so as to step down the DC voltage applied between the second conductive paths 22A and 22B and apply a DC voltage between the third conductive paths 23A and 23B. The second power conversion unit 60 may perform a boosting operation so as to boost the DC voltage applied between the third conductive paths 23A and 23B and apply the DC voltage between the second conductive paths 22A and 22B. The circuit configuration of the second power conversion unit 60 is not particularly limited as long as it functions as a bidirectional DCDC converter, but the circuit can be, for example, as shown in FIG. In the example of FIG. 3, the second power conversion unit 60 is configured as an isolated bidirectional DCDC converter. The second power conversion unit 60 includes a first conversion circuit 61, a transformer 63, and a second conversion circuit 62.

The first conversion circuit 61 corresponds to an example of one conversion unit. The first conversion circuit 61 has a function of converting DC power and AC power in both directions. The first conversion circuit 61 has a function of converting the DC voltage applied between the second conductive paths 22A and 22B to generate an AC voltage in the first coil 63A (first operation). The first conversion circuit 61 also has a function of converting an AC voltage generated in the first coil 63A and outputting a DC voltage between the second conductive paths 22A and 22B (second operation). The first conversion circuit 61 includes a capacitor 61A and switch elements 61C, 61D, 61E, 61F constituting a full bridge circuit. The transformer 63 includes a first coil 63A connected to the first conversion circuit 61 and a second coil 63B connected to the second conversion circuit 62. The first coil 63A and the second coil 63B are magnetically coupled. The second conversion circuit 52 corresponds to an example of another conversion unit. The first coil 63A corresponds to an example of the primary coil. The second coil 63B corresponds to an example of the secondary coil. The second conversion circuit 62 has a function of converting AC power and DC power in both directions. The second conversion circuit 62 has a function of converting an AC voltage generated in the second coil 63B and outputting a DC voltage between the third conductive paths 23A and 23B (third operation). The second conversion circuit 62 has a function of converting the DC voltage applied between the third conductive paths 23A and 23B to generate an AC voltage in the second coil 63B (fourth operation). The second conversion circuit 62 includes switch elements 62C, 62D, an inductor 62E, a capacitor 62A, and the like. The configuration of FIG. 3 is merely an example, and a part or both of the first power conversion unit 50 and the second power conversion unit 60 may be an On Board Charger (vehicle-mounted charger).

A typical example of the conversion device 10 described below has a specific configuration as shown in FIG. In FIGS. 4 to 8, the blocking portions 91 and 92 are omitted. In the conversion device 10 according to the example of FIG. 4, a first high voltage load 5A and a second high voltage load 5B are provided as specific examples of the high voltage load 5 shown in FIG. In the example of FIG. 4, each high-voltage load is provided in a configuration in which each battery is connected in parallel. Specifically, the first high-voltage load 5A is provided in a configuration connected in parallel with the first high-voltage battery 34A. A second high-voltage load 5B is provided so as to be connected in parallel with the second high-voltage battery 34B. One end of the first high voltage load 5A is electrically connected to the first conductive path 21A, and the other end is electrically connected to the first conductive path 21B. In this configuration, for example, the current supplied from the first high voltage battery 34A or the first power conversion unit 50 via the first conductive path 21A can be supplied to the first high voltage load 5A. One end of the second high voltage load 5B is electrically connected to the second conductive path 22A, and the other end is electrically connected to the second conductive path 22B. In this configuration, for example, the current supplied from the second high voltage battery 34B or the second power conversion unit 60 via the second conductive path 22A can be supplied to the second high voltage load 5B.

In the representative example of FIG. 4, the switch 26A and the fuse 24 are provided in the first conductive path 21A. The switch 26A is a switch that switches the first conductive path 21A between a conductive state and a cutoff state. A switch 26B is provided on the first conductive path 21B. The switch 26B is a switch that switches the first conductive path 21B between a conductive state and a cutoff state. The second conductive path 22A is provided with a switch 27A and a fuse 25. The switch 27A is a switch that switches the second conductive path 22A between a conductive state and a cutoff state. A switch 27B is provided on the second conductive path 22B. The switch 27B is a switch that switches the second conductive path 22B between a conductive state and a cutoff state.

(Overview of imbalance suppression operation)
The conversion device 10 determines whether or not the predetermined condition is satisfied at the predetermined determination time, and when the predetermined condition is satisfied at the predetermined determination time, the plurality of batteries (first high voltage battery 34A and second high voltage battery 34B). ) Is performed to suppress the imbalance. The predetermined determination time may be, for example, when the high-voltage batteries 34 are connected in series, or may be other times. For example, the control unit 18 may determine whether or not a predetermined condition is satisfied while the vehicle is starting with the vehicle start switch turned on, and the external AC power supply and the conversion device 10 are electrically connected. If this is the case, it may be determined whether or not the predetermined condition is satisfied. In the following description, "when the high-voltage battery 34 is connected in series while the vehicle is starting with the vehicle start switch turned on" is the determination time.

Specifically, the control unit 18 determines whether or not the predetermined condition is satisfied at the determination time. The predetermined condition is, for example, "in a plurality of batteries, the difference between the output voltage of any one battery and the output voltage of the other battery becomes larger than a certain value". The output voltage of a battery is, for example, the potential difference between the electrode having the lowest potential and the electrode having the highest potential in the battery. In the example of the following description, in the control unit 18, the absolute value (| Va-Vb |) of the difference between the output voltage Va of the first high voltage battery 34A and the output voltage Vb of the second high voltage battery 34B becomes the threshold value V1 or more. That is "the predetermined condition is satisfied". Then, the control unit 18 causes the power conversion unit 40 to perform an imbalance suppression operation when | Va—Vb | ≧ V1 at the above determination time.

In the example of FIG. 1, the management device 17 has an output voltage Va of the first high voltage battery 34A and an output voltage Vb of the second high voltage battery 34B when power is supplied to itself (for example, while the vehicle is starting). Is continuously monitored, and the output voltages Va and Vb are continuously applied to the control unit 18. The management device 17 may periodically supply the output voltages Va and Vb to the control unit 18 at short time intervals, or may supply the output voltages Va and Vb to the control unit 18 when predetermined conditions are satisfied. good. The control unit 18 continuously monitors the output voltages Va and Vb by acquiring the information of the output voltages Va and Vb transmitted from the management device 17. The control unit 18 monitors the output voltages Va and Vb at the above determination time, and continuously determines whether or not | Va—Vb | ≧ V1. The control unit 18 may periodically determine whether or not | Va-Vb | ≧ V1 at short time intervals, and when a predetermined condition is satisfied, | Va-Vb | ≧ V1. It may be determined whether or not.

When the control unit 18 determines that | Va-Vb | ≧ V1 at the above determination time, the power conversion unit 40 causes the power conversion unit 40 to perform an imbalance suppression operation. The time for causing the power conversion unit 40 to perform the imbalance suppression operation may be the above-mentioned determination time, or may be another predetermined time. When the power conversion unit 40 is to perform the imbalance suppression operation, the control unit 18 sets the battery having the larger output voltage into the discharged state or the charging stopped state, and charges the battery having the smaller output voltage. The power conversion unit 40 is made to perform power conversion so as to be performed. As described above, when the predetermined start condition is satisfied (that is, when the predetermined condition is satisfied at the determination time), the control unit 18 has a plurality of batteries (first high voltage battery 34A) for the power conversion unit 40. And the operation of reducing the difference between the output voltages Va and Vb of the second high-voltage battery 34B) is performed.

As the imbalance suppressing operation, for example, the operations shown in FIGS. 5 to 8 can be performed. The operation of FIGS. 5 and 6 is an operation of performing a step-down operation and a boosting operation by using the electric power from one of the high-voltage batteries 34 without using the electric power of the low-voltage battery 32, and charging the other battery. Is. The operations of FIGS. 7 and 8 are operations in which a boosting operation is performed using the electric power from the low voltage battery 32 to charge another battery. In the examples of FIGS. 5 to 8, the output voltage Va of the first high-voltage battery 34A is larger than the output voltage Vb of the second high-voltage battery 34B, and | Va-Vb | ≧ V1.

In the operations of FIGS. 5, 6 and 8, the converter corresponding to the battery having the relatively large output voltage among the plurality of batteries has the first conductive path 21A or the second from the battery having the larger output voltage. A step-down operation (first conversion operation) is performed using the electric power supplied to itself via one of the conductive paths 22A as an input power, and the electric power is output to the third conductive path 23A. Further, the converter corresponding to the battery having the relatively smaller output voltage among the plurality of batteries performs a boosting operation (second conversion operation) using the power supplied to itself via the third conductive path 23A as the input power. Is performed, and power is output to the other of the first conductive path 21A or the second conductive path 22A. In the examples of FIGS. 5, 6, and 8, the control unit 18 causes one of the plurality of converters to perform the first conversion operation, and the other instruction (control) to perform the second conversion operation is "one from the outside." It corresponds to an example of "part charge instruction". The partial charge instruction is an instruction to control the power conversion unit so as to discharge one of the plurality of batteries and charge the other battery. That is, the instruction to operate the power conversion unit 40 in any of the first mode, the second mode, and the fourth mode described later corresponds to an example of the "partial charge instruction from the outside". The power conversion unit 40 outputs electric power to the third conductive path 23A based on the electric power supplied from one battery by one converter in response to such a partial charging instruction from the outside (control unit 18). The first conversion operation is performed as described above, and the second conversion operation is performed so that the other converter outputs power to the other battery based on the power supplied from the third conductive path 23A.

In the operation of FIG. 7, the instruction (control) in which the control unit 18 stops one of the plurality of converters and causes the other converter to perform the second conversion operation is an example of the “partial stop instruction from the outside”. Equivalent to. That is, the instruction to operate the power conversion unit 40 in the third mode described later corresponds to an example of "partial stop instruction from the outside". The partial stop instruction is an instruction to control the power conversion unit so as to stop one of the plurality of converters and charge another battery corresponding to the other converter. The power conversion unit 40 is based on the power supplied from the low voltage battery 32 to the other converter while the conversion operation is stopped by one converter in response to such a partial stop instruction from the outside (control unit 18). The second conversion operation is performed so as to output power to another battery.

(Operation in the first mode)
The control unit 18 operates the power conversion unit 40 in the first mode as shown in FIG. 5 when the first operation condition is satisfied when the predetermined condition is satisfied at the determination time. The first operating condition is, for example, a case where the second operating condition, the third operating condition, and the fourth operating condition, which will be described later, are not satisfied. When the power conversion unit 40 is operated in the first mode as shown in FIG. 5, the control unit 18 steps down the DC voltage applied between the first conductive paths 21A and 21B to the first power conversion unit 50. The first conversion operation (step-down operation) is performed so that a DC voltage is applied between the third conductive paths 23A and 23B. Then, in parallel with this first conversion operation, the control unit 18 boosts the DC voltage applied between the third conductive paths 23A and 23B and applies the DC voltage between the second conductive paths 22A and 22B. The second power conversion unit 60 is made to perform the second conversion operation (boosting operation). When the power conversion unit 40 operates in the first mode, the first power conversion unit 50 supplies power to the third conductive path 23A, and all of this power is used when the second power conversion unit 60 performs the second conversion operation. It is used as the input power of. That is, the power conversion unit 40 does not supply power to the low voltage battery 32 and the low voltage load 8 during the operation of the first mode.

In the example of FIG. 5, when the power conversion unit 40 is operated in the first mode, the control unit 18 has, for example, the current output by the first power conversion unit 50 to the third conductive path 23A by the first conversion operation, and the first (2) The first power conversion unit 50 and the second power conversion unit 60 are operated so that the current input from the third conductive path 23A is the same as the current input by the power conversion unit 60 in the second conversion operation. The control unit 18 monitors the input / output current and the input / output voltage of the first power conversion unit 50 via the first conductive paths 21A and 21B. Further, the control unit 18 monitors the input / output current and the input / output voltage of the first power conversion unit 50 via the third conductive paths 23A and 23B. Further, the control unit 18 monitors the input / output current and the input / output voltage of the second power conversion unit 60 via the second conductive paths 22A and 22B. Further, the control unit 18 monitors the input / output current and the input / output voltage of the second power conversion unit 60 via the third conductive paths 23A and 23B.

(Operation in the second mode)
The control unit 18 operates the power conversion unit 40 in the second mode as shown in FIG. 6 when the second operating condition is satisfied when the predetermined condition is satisfied at the determination time. The second operating condition is, for example, "the load current supplied to the low voltage load 8 is equal to or higher than a certain value". The case where the power conversion unit 40 operates in the second mode is "the case where the power conversion unit 40 receives a partial charge instruction from the outside and the first condition is met". The first condition in this case is that "the instruction given from the control unit 18 to the power conversion unit 40 is an instruction to make the power output by the first conversion operation larger than the power output by the second conversion operation". Is. When the power conversion unit 40 is operated in the second mode as shown in FIG. 6, the control unit 18 steps down the DC voltage applied between the first conductive paths 21A and 21B to the first power conversion unit 50. The first conversion operation (step-down operation) is performed so that a DC voltage is applied between the third conductive paths 23A and 23B. Then, in parallel with this first conversion operation, the control unit 18 boosts the DC voltage applied between the third conductive paths 23A and 23B and applies the DC voltage between the second conductive paths 22A and 22B. The second power conversion unit 60 is made to perform the second conversion operation (boosting operation). When the power conversion unit 40 operates in the second mode as shown in FIG. 6, the first power conversion unit 50 supplies power to the third conductive path 23A, and a part of this power is converted to the second power. The unit 60 is used as input power when performing the second conversion operation, and the other part is supplied to the low pressure battery 32 or the low pressure load 8.

In the example of FIG. 6, when the power conversion unit 40 is operated in the second mode, for example, the control unit 18 is more than the current input from the third conductive path 23A by the second power conversion unit 60 in the second conversion operation. The first power conversion unit 50 and the second power conversion unit 60 are operated so that the current output by the first power conversion unit 50 to the third conductive path 23A by the first conversion operation becomes larger.

The control unit 18 operates the power conversion unit 40 in the third mode as shown in FIG. 7 when the third operating condition is satisfied when the predetermined condition is satisfied at the determination time. The third operating condition is, for example, "the SOC of the battery having the larger output voltage (the first high voltage battery 34A in the example of FIG. 7) is less than a predetermined value". When the power conversion unit 40 is operated in the third mode, the control unit 18 stops the operation of the converter corresponding to the one battery having the larger output voltage, and corresponds to the other battery having the smaller output voltage. The converter is made to perform the second conversion operation so as to output the electric power to the other battery based on the electric power supplied from the low voltage battery 32 (second battery). For example, when the power conversion unit 40 operates in the third mode as shown in FIG. 7, the operation of the first power conversion unit 50 is stopped, and the power conversion unit 40 is based on the power supplied from the low voltage battery 32 (second battery). The second power conversion unit 60 is made to perform the second conversion operation so as to boost the DC voltage applied between the third conductive paths 23A and 23B and apply the DC voltage between the second conductive paths 22A and 22B.

The control unit 18 operates the power conversion unit 40 in the fourth mode as shown in FIG. 8 when the fourth operating condition is satisfied when the predetermined condition is satisfied at the determination time. The fourth operating condition is, for example, "the load current to the high voltage load provided corresponding to the battery having a small output voltage among the plurality of batteries is equal to or greater than the threshold current". For example, when the output voltage of the second high-voltage battery 34B is smaller than that of the first high-voltage battery 34A, the load current to the second high-voltage load 5B provided corresponding to the second high-voltage battery 34B having a relatively small output voltage. When is equal to or greater than the threshold current, it is assumed that the fourth operating condition is satisfied.

The case of operating in the fourth mode is the case of the second condition when the power conversion unit 40 receives a partial charge instruction from the outside. The second condition in this case is that "the instruction given to the power conversion unit 40 is an instruction to make the power output by the second conversion operation larger than the power output by the first conversion operation". When the power conversion unit 40 is operated in the fourth mode as shown in FIG. 8, the control unit 18 steps down the DC voltage applied between the first conductive paths 21A and 21B to the first power conversion unit 50. 3 The first conversion operation (step-down operation) is performed so that a DC voltage is applied between the conductive paths 23A and 23B. Then, in parallel with this first conversion operation, the control unit 18 boosts the DC voltage applied between the third conductive paths 23A and 23B and applies the DC voltage between the second conductive paths 22A and 22B. The second power conversion unit 60 is made to perform the second conversion operation (boosting operation). When the power conversion unit 40 operates in the fourth mode as shown in FIG. 8, the first power conversion unit 50 supplies power to the third conductive path 23A, and all of this power and the low-voltage battery 32 supply power. The electric power combined with the electric power is used as the input electric power when the second electric power conversion unit 60 performs the second conversion operation.

In the example of FIG. 8, when the power conversion unit 40 is operated in the fourth mode, for example, the control unit 18 is more than the current output by the first power conversion unit 50 to the third conductive path 23A by the first conversion operation. The first power conversion unit 50 and the second power conversion unit 60 are operated so that the current input from the third conductive path 23A by the second power conversion unit 60 is larger in the second conversion operation.

The control unit 18 ends the imbalance suppression operation when the end condition is satisfied, regardless of whether the power conversion unit 40 is operated in any of the first to fourth modes. The termination condition may be, for example, when the absolute value of the difference between the output voltage Va of the first high-voltage battery 34A and the output voltage Vb of the second high-voltage battery 34B is smaller than the threshold value V1 and becomes a constant value or less. It may be the case where Va = Vb, or the case where a certain time has elapsed from the start of the imbalance suppression operation.

The following description relates to the effect of the first embodiment.
In the conversion device 10, the power conversion unit 40 not only performs a first conversion operation in which power is converted by using the power supplied from each battery as an input for a plurality of batteries constituting the high-voltage battery 34, but also for any of the batteries. A second conversion operation that outputs electric power individually can also be performed. Therefore, the conversion device 10 is easier to correct the imbalance of a plurality of batteries than the device that can realize only the first conversion operation.

The conversion device 10 is provided with each converter (first power conversion unit 50, second power conversion unit 60) corresponding to each battery (first high voltage battery 34A, second high voltage battery 34B) constituting the high voltage battery 34. Be done. Therefore, the conversion device 10 can be made redundant by a plurality of converters while realizing a configuration that makes it easy to correct the imbalance of the plurality of batteries.

As shown in FIGS. 5, 6, and 8, the conversion device 10 supplies electric power to the third conductive paths 23A and 23B by converting the electric power of one converter based on the electric power of one battery, and uses this electric power. Other batteries can be charged by the power conversion of the converter. Therefore, the conversion device 10 can correct the imbalance of the plurality of batteries more quickly.

As shown in FIGS. 7 and 8, the conversion device 10 can correct the imbalance of a plurality of batteries by using the electric power from the low voltage battery 32 (second battery).

As shown in FIG. 7, the conversion device 10 can supply power to the other battery side by giving priority to the power supply from the low-voltage battery 32 (second battery) over the power supply from one battery.

The conversion device 10 can operate the power conversion unit 40 so as to reduce the difference between the output voltages of the plurality of batteries when the above-mentioned start condition is satisfied.

<Second Embodiment>
The following description relates to the conversion device 210 of the second embodiment.
The circuit configuration of the conversion device 210 of the second embodiment is different from that of the conversion device 10 of the first embodiment only in that the power conversion unit 40 shown in FIG. 1 and the like is changed to the power conversion unit 240. That is, the conversion device 210 of the second embodiment has a configuration in which the power conversion unit 40 is changed to the power conversion unit 240 in the conversion device 10 of FIG. Therefore, in the following description, FIG. 1 is referred to for parts other than the power conversion unit 40. The device configuration of the vehicle-mounted system 202 of FIG. 9 differs from the vehicle-mounted system 2 (FIGS. 1, 4, etc.) of the first embodiment only in that the power conversion unit 40 is changed to the power conversion unit 240, and the other points are different. It is the same as the in-vehicle system 2 of the first embodiment. The apparatus configuration of the power supply system 203 of FIG. 9 differs from the power supply system 3 of the first embodiment (FIGS. 1, 4, etc.) only in that the power conversion unit 40 is changed to the power conversion unit 240, and the other points are different. It is the same as the power supply system 3 of the first embodiment. The operation of the in-vehicle system 202 is the same as that of the in-vehicle system 2 except for the operation of the power conversion unit 240.

In the power supply system 203 to which the conversion device 210 of the second embodiment is applied, as shown in FIGS. 1 and 9, a plurality of batteries (first high voltage battery 34A, second high voltage battery 34B) are connected in series and in parallel. It is a switching power supply system. The conversion device 210 of the second embodiment has a power conversion unit 240. The power conversion unit 240 converts the power input from each battery (first high-voltage battery 34A, second high-voltage battery 34B) and outputs the power to the third conductive paths 23A and 23B different from each battery. The first conversion operation can be performed. The power conversion unit 240 may perform a second conversion operation so as to individually output power to each of the first high-voltage battery 34A and the second high-voltage battery 34B.

As shown in FIG. 10, the power conversion unit 240 includes a plurality of first conversion units 241A and 241B, a transformer 243, and a second conversion unit 242. The transformer 243 includes a plurality of first coils 243A, 243B and a second coil 243C, and the plurality of first coils 243A, 243B and the second coil 243C are magnetically coupled. Each of the plurality of first coils 243A and 243B is provided corresponding to each of the plurality of first conversion units 241A and 241B. Each of the plurality of first conversion units 241A and 241B converts DC power based on the power from each of the first high voltage battery 34A and the second high voltage battery 34B, and converts AC power into each of the plurality of first coils 243A and 243B. Is output.

The first conversion unit 241A has a function of converting DC power and AC power in both directions. The first conversion unit 241A has a function of converting a DC voltage applied between the first conductive paths 21A and 21B and generating an AC voltage in the first coil 243A. The first conversion unit 241A also has a function of converting an AC voltage generated in the first coil 243A and outputting a DC voltage between the first conductive paths 21A and 21B. The first conversion unit 241A includes a capacitor 251A and switch elements 251C, 251D, 251E, 251F constituting a full bridge circuit.

The first conversion unit 241B has a function of converting DC power and AC power in both directions. The first conversion unit 241B has a function of converting the DC voltage applied between the second conductive paths 22A and 22B and generating an AC voltage in the first coil 243B. The first conversion unit 241B also has a function of converting an AC voltage generated in the first coil 243B and outputting a DC voltage between the second conductive paths 22A and 22B. The first conversion unit 241B includes a capacitor 261A and switch elements 261C, 261D, 261E, 261F constituting a full bridge circuit.

The second conversion unit 242 has a function of converting AC power and DC power in both directions. The second conversion unit 242 has a function of converting an AC voltage generated in the second coil 243C and outputting a DC voltage between the third conductive paths 23A and 23B. The second conversion unit 242 also has a function of converting the DC voltage applied between the third conductive paths 23A and 23B to generate an AC voltage in the second coil 53B. The second conversion unit 242 includes switch elements 252C, 252D, an inductor 252E, a capacitor 252A, and the like.

Similar to the conversion device 10, the conversion device 210 determines whether or not the predetermined condition is satisfied at the predetermined determination time, and when the predetermined condition is satisfied at the determination time, the plurality of batteries (first high voltage battery). The operation of suppressing the imbalance of the 34A and the second high voltage battery 34B) is performed. The determination timing and the predetermined conditions can be the same as those of the conversion device 10 of the first embodiment. In the following example, when the control unit 18 shown in FIG. 1 determines that | Va—Vb | ≧ V1 at the above determination time, the power conversion unit 240 is made to perform an imbalance suppression operation. The time for causing the power conversion unit 240 to perform the imbalance suppression operation may be the above-mentioned determination time, or may be another predetermined time. When the power conversion unit 240 is to perform the imbalance suppression operation, the control unit 18 sets the battery having the larger output voltage into the discharged state or the charging stopped state, and charges the battery having the smaller output voltage. The power conversion unit 240 is made to perform power conversion so as to be performed. As described above, when the predetermined start condition is satisfied (that is, when the predetermined condition is satisfied at the determination time), the control unit 18 has a plurality of batteries (first high voltage battery 34A) for the power conversion unit 240. And the operation of reducing the difference between the output voltages Va and Vb of the second high-voltage battery 34B) is performed.

The control unit 18 can cause the power conversion unit 240 to perform the operations shown in FIGS. 11 to 13, for example, as the imbalance suppression operation. The operations of FIGS. 11 and 12 are operations in which the conversion operation is performed by using the electric power from one of the high-voltage batteries 34 without using the electric power of the low-voltage battery 32, and the other batteries are charged. The operation of FIG. 13 is an operation of performing a step-up operation using the electric power from the low-voltage battery 32 to charge one of the high-voltage batteries 34. In the examples of FIGS. 11 to 13, the output voltage Va of the first high-voltage battery 34A is larger than the output voltage Vb of the second high-voltage battery 34B, and | Va-Vb | ≧ V1.

The control unit 18 operates the power conversion unit 240 in the first mode as shown in FIG. 11 when the first operating condition is satisfied when the predetermined condition is satisfied at the determination time. The first operating condition is, for example, a case where the second operating condition and the third operating condition described later are not satisfied. The instruction given to the power conversion unit 240 so that the control unit 18 performs the operation shown in FIG. 11 corresponds to an example of "partial charge instruction from the outside". The power conversion unit 240 performs power conversion by a plurality of first conversion units 241A, 241B and a transformer 243 based on the power supplied from one battery in response to such a partial charge instruction from the outside. The second conversion operation is performed so as to supply power to another battery. When the control unit 18 operates the power conversion unit 240 in the first mode as shown in FIG. 11, the second conversion unit 242 maintains the stopped state, and the first conductive paths 21A and 21B with respect to the first conversion unit 241A. An AC voltage is generated in the first coil 243A by performing a conversion operation with the DC voltage applied between them as an input, and the AC voltage of the first coil 243B generated in response to the AC voltage is used as an input in the first conversion unit. By causing the 241B to perform the conversion operation, the plurality of first conversion units 241A and 241B are operated so as to apply a DC voltage between the second conductive paths 22A and 22B.

The control unit 18 monitors the input / output current and the input / output voltage of the first conversion unit 241A via the first conductive paths 21A and 21B. Further, the control unit 18 monitors the input / output current and the input / output voltage of the first conversion unit 241B via the second conductive paths 22A and 22B. Further, the control unit 18 monitors the input / output current and the input / output voltage of the second conversion unit 242 via the third conductive paths 23A and 23B.

The control unit 18 operates the power conversion unit 240 in the second mode as shown in FIG. 12 when the second operating condition is satisfied when the predetermined condition is satisfied at the determination time. The second operating condition is, for example, a case where the load current flowing to the low voltage load 8 is a predetermined value or more. The instruction given to the power conversion unit 240 so that the control unit 18 performs the operation shown in FIG. 12 also corresponds to an example of the “partial charge instruction from the outside”. When the power conversion unit 240 is operated in the second mode as shown in FIG. 12, the control unit 18 inputs the DC voltage applied between the first conductive paths 21A and 21B to the first conversion unit 241A. By performing the operation, an AC voltage is generated in the first coil 243A. Further, the control unit 18 causes the first conversion unit 241B to perform a conversion operation in which the AC voltage generated in the first coil 243B is input in response to the generation of the AC voltage in the first coil 243A. A DC voltage is applied between the conductive paths 22A and 22B. Further, the control unit 18 causes the second conversion unit 242 to perform a conversion operation by inputting the AC voltage generated in the second coil 243C in response to the generation of the AC voltage in the first coil 243A, thereby causing the third conductivity. A DC voltage is applied between the paths 23A and 23B.

The control unit 18 operates the power conversion unit 240 in the third mode as shown in FIG. 13 when the third operating condition is satisfied when the predetermined condition is satisfied at the determination time. The third operating condition is, for example, "the SOC of the battery having the larger output voltage (the first high voltage battery 34A in the example of FIG. 13) is less than a predetermined value". When the power conversion unit 240 is operated in the third mode, the control unit 18 stops the conversion operation of the first conversion unit corresponding to the battery having the larger output voltage, while stopping the conversion operation with the other first conversion unit and the transformer. The power conversion unit 240 is provided with power so that the 243 and the second conversion unit 242 output power to another battery corresponding to the other first conversion unit based on the power supplied from the low voltage battery 32 (second battery). 2 Perform the conversion operation. The instruction given by the control unit 18 to the power conversion unit 240 so as to perform the operation of FIG. 13 corresponds to an example of "partial stop instruction from the outside".

When the power conversion unit 240 is operated in the third mode as shown in FIG. 13, the control unit 18 maintains the first conversion unit 241A in a stopped state, and the third conductive paths 23A and 23B with respect to the second conversion unit 242. An AC voltage is generated in the second coil 243C by performing a conversion operation using the DC voltage applied between them as an input. Further, the control unit 18 causes the first conversion unit 241B to perform a conversion operation in which the AC voltage generated in the first coil 243B is input in response to the generation of the AC voltage in the second coil 243C. A DC voltage is applied between the conductive paths 22A and 22B.

<Third Embodiment>
The following description relates to the conversion device 310 of the third embodiment.
FIG. 14 shows the conversion device 310 according to the third embodiment. The conversion device 310 is a device used as a part of the in-vehicle system 302 mounted on the vehicle. The vehicle equipped with the in-vehicle system 302 is a vehicle in which the in-vehicle system 302 is installed in place of the in-vehicle system 2 by modifying the vehicle 1 in FIG.

The in-vehicle system 302 shown in FIG. 14 includes a power supply system 303, a drive unit 4, a high voltage load 5, a low voltage load 8, power paths 28A, 28B, and the like. The power paths 28A and 28B may be provided with terminals having the same functions as the terminals 9A and 9B shown in FIG. Further, the power paths 28A and 28B may be provided with switches having the same functions as the switches 26A and 26B shown in FIG.

The drive unit 4 has the same configuration as the drive unit 4 of the vehicle-mounted system 2 shown in FIG. 1 and the like, and has the same function as the drive unit 4 of the vehicle-mounted system 2. The low-voltage load 8 has the same configuration as the low-voltage load 8 of the vehicle-mounted system 2 shown in FIG. 1 and the like, and has the same function as the low-voltage load 8 of the vehicle-mounted system 2. The high-voltage load 5 is a load that is electrically connected to the power paths 28A and 28B and can operate by being supplied with electric power from the high-voltage battery 34. The high-voltage load 5 is, for example, an air conditioner, a heater, or the like, and may be an electric device other than these.

The power supply system 303 includes a conversion device 310, a low voltage battery 32, and a high voltage battery 34. The power supply system 303 is a system in which a plurality of batteries 34A and 34B are connected in parallel, and the plurality of batteries 34A and 34B are not switched to a series connection.

The power supply system 303 can charge the high voltage battery 34 based on the AC power supplied from the external AC power source when the external AC power source (not shown) is connected to the vehicle equipped with the in-vehicle system 302. The vehicle equipped with the in-vehicle system 302 has a connection terminal (not shown) to which an external AC power supply is connected, and an external AC power supply (not shown) may be connected to the connection terminal. The power supply system 303 has a charging circuit (not shown) that applies a DC voltage to the high voltage battery 34 based on the electric power supplied from the quick charger when the quick charger is connected to the connection terminal of the vehicle. ..

The power path 28A may be electrically connected to the highest potential electrode in each of the first high voltage battery 34A and the second high voltage battery 34B. The power paths 28A and 28B are paths for supplying electric power from the high-voltage battery 34 to the inverter 7.

The high voltage battery 34 includes a plurality of batteries. In the configuration of FIG. 14, the high voltage battery 34 includes a first high voltage battery 34A and a second high voltage battery 34B. The first high voltage battery 34A and the second high voltage battery 34B both correspond to an example of a battery. The first high voltage battery 34A corresponds to an example of the first battery unit. The second high voltage battery 34B corresponds to an example of the second battery unit. The high-voltage battery 34 is a power source in which the first high-voltage battery 34A and the second high-voltage battery 34B are connected in parallel and do not switch to the series connection. The high-voltage battery 34 is configured to be rechargeable and dischargeable. When power is supplied from the high-voltage battery 34, power is supplied from either one of the first high-voltage battery 34A and the second high-voltage battery 34B, or power is supplied in a state where both are connected in parallel. The high voltage battery 34 outputs a high voltage (for example, about 300 V) for driving the drive unit 4. The output voltage of each of the first high-voltage battery 34A and the second high-voltage battery 34B when fully charged is higher than the output voltage of the low-voltage battery 32 when fully charged. The first high-voltage battery 34A and the second high-voltage battery 34B may be composed of a lithium ion battery or may be composed of other types of storage batteries.

A relay 393A is provided between the first high voltage battery 34A and the power path 28A. When the relay 393A is in the off state, the electrode having the highest potential (high potential side electrode) in the first high-voltage battery 34A and the power path 28A are electrically disconnected, and the energization via the relay 393A is cut off. .. When the relay 393A is in the ON state, the high potential side electrode of the first high pressure battery 34A and the power path 28A are electrically connected, and between the high potential side electrode of the first high pressure battery 34A and the power path 28A. Shorts out.

A relay 394A is provided between the first high voltage battery 34A and the power path 28B. When the relay 394A is in the off state, the energization via the relay 394A is cut off between the electrode having the lowest potential (low potential side electrode) in the first high voltage battery 34A and the power path 28B. When the relay 394A is on, the low potential side electrode of the first high pressure battery 34A and the power path 28B are electrically connected, and between the low potential side electrode of the first high pressure battery 34A and the power path 28B. Shorts out. Further, a series component in which the relay 395A and the resistor 396A are provided in series is connected in parallel to the relay 394A. When the relay 393A is in the on state, the relay 394A is in the off state, and the relay 395A is in the on state, a current can flow through the series component. In this case, the electric power is supplied while suppressing the current. When the relays 394A and 395A are in the off state, the energization between the first high voltage battery 34A and the power path 28B is cut off. The relays 393A, 394A, and 395A may be semiconductor relays or mechanical relays.

A relay 393B is provided between the second high voltage battery 34B and the power path 28A. When the relay 393B is in the off state, the electrode having the highest potential (high potential side electrode) in the second high-voltage battery 34B and the power path 28A are electrically disconnected, and the energization via the relay 393B is cut off. .. When the relay 393B is in the ON state, the high potential side electrode of the second high voltage battery 34B and the power path 28A are electrically connected, and between the high potential side electrode of the second high pressure battery 34B and the power path 28A. Shorts out.

A relay 394B is provided between the second high voltage battery 34B and the power path 28B. When the relay 394B is in the off state, the power supply via the relay 394B is cut off between the electrode having the lowest potential (low potential side electrode) in the second high voltage battery 34B and the power path 28B. When the relay 394B is on, the low potential side electrode of the second high pressure battery 34B and the power path 28B are electrically connected, and between the low potential side electrode of the second high pressure battery 34B and the power path 28B. Shorts out. Further, a series component in which the relay 395B and the resistor 396B are provided in series is connected in parallel to the relay 394B. When the relay 393B is in the on state, the relay 394B is in the off state, and the relay 395B is in the on state, a current can flow through the series component. In this case, the electric power is supplied while suppressing the current. When the relays 394B and 395B are in the off state, the energization between the second high voltage battery 34B and the power path 28B is cut off. The relays 393B, 394B, and 395B may be semiconductor relays or mechanical relays.

The low voltage battery 32 corresponds to an example of the second battery and corresponds to an example of the power storage unit. The low voltage battery 32 is configured to be rechargeable and dischargeable. The low voltage battery 32 supplies power to the low voltage load 8. The low voltage battery 32 may be composed of a lead storage battery or another type of storage battery. The low voltage battery 32 outputs a predetermined voltage (for example, 12V) when fully charged.

(Configuration of converter)
As shown in FIG. 14, the conversion device 310 mainly includes a power conversion unit 40, a control unit 18, a management device 17, a first relay unit 331, and a second relay unit 332. The conversion device 310 functions as a power control device. The conversion device 310 is a device capable of performing power conversion by inputting power supplied from the high voltage battery 34 or the low voltage battery 32. Reference numeral 370 is a DCDC converter, which is composed of a power conversion unit 40, a first relay unit 331, a second relay unit 332, and the like.

The control unit 18 is a device that performs various controls on the devices in the in-vehicle system 302. The control unit 18 has a calculation function, an information processing function, a storage function, and the like. The control unit 18 may be configured by a plurality of electronic control devices, or may be configured by a single electronic control device. The control unit 18 controls, for example, the power conversion unit 40. Specific examples of control of the power conversion unit 40 by the control unit 18 will be described in detail later.

The management device 17 has a function of monitoring the high voltage battery 34. The management device 17 continuously detects the output voltage and SOC (State Of Charge) of each of the plurality of batteries (first high-voltage battery 34A and second high-voltage battery 34B) constituting the high-voltage battery 34.

The power conversion unit 40 of the conversion device 310 has the same configuration as the power conversion unit 40 of the first embodiment shown in FIGS. 1, 2, and the like, and functions in the same manner. The power conversion unit 40 of the conversion device 310 also includes a plurality of converters. As shown in FIGS. 14 and 15, the power conversion unit 40 of the conversion device 310 includes a first power conversion unit 50 and a second power conversion unit 60 as a plurality of converters. The first power conversion unit 50 corresponds to an example of the first converter. The second power conversion unit 60 corresponds to an example of the second converter. Each of the first power conversion unit 50 and the second power conversion unit 60 performs power conversion in both directions.

Each of the plurality of converters (first power conversion unit 50, second power conversion unit 60) is provided corresponding to each of the plurality of batteries (first high voltage battery 34A, second high voltage battery 34B). A first power conversion unit 50 is provided corresponding to the first high voltage battery 34A. A second power conversion unit 60 is provided corresponding to the second high voltage battery 34B. The first power conversion unit 50 responds so that it can receive power supply from the first high voltage battery 34A even when the power supply from the second high voltage battery 34B different from the first high voltage battery 34A corresponding to itself is cut off. Is provided. The second power conversion unit 60 responds so that it can receive power supply from the second high voltage battery 34B even when the power supply from the first high voltage battery 34A, which is different from the second high voltage battery 34B corresponding to itself, is cut off. Is provided.

A first conductive path 21A (first wiring section) is provided between the high potential side electrode (the electrode having the highest potential) of the first high voltage battery 34A (first battery section) and the first terminal 371. A first conductive path 21B (second wiring portion) is provided between the low-potential side electrode (the electrode having the lowest potential) of the first high-voltage battery 34A and the second terminal 372. The first terminal 371 may be electrically connected to the high potential side electrode of the first high voltage battery 34A via the first conductive path 21A. The first terminal 371 may always be short-circuited to the high potential side electrode of the first high voltage battery 34A via the first conductive path 21A. Alternatively, a switch may be interposed in the first conductive path 21A. In this case, when the switch of the first conductive path 21A is in the ON state, the first terminal 371 is the height of the first high voltage battery 34A. It may be short-circuited to the potential side electrode. The second terminal 372 may be electrically connected to the low potential side electrode of the first high voltage battery 34A via the first conductive path 21B. The second terminal 372 may always be short-circuited to the low potential side electrode of the first high voltage battery 34A via the first conductive path 21B. Alternatively, a switch may be interposed in the first conductive path 21B. In this case, when the switch of the first conductive path 21B is in the ON state, the second terminal 372 is the low voltage of the first high voltage battery 34A. It may be short-circuited to the potential side electrode. The first conductive paths 21A and 21B are paths to which a voltage based on the voltage across the first high voltage battery 34A is applied.

The first power conversion unit 50 converts the voltage applied between the first conductive path 21A on one side and the first conductive path 21B on the other side so as to step down the voltage, and converts the voltage into the third conductive path 23A on one side. An operation of applying an output voltage to the other third conductive path 23B is performed. The first power conversion unit 50 has the same configuration as the first power conversion unit 50 of the first embodiment shown in FIGS. 1, 2, and the like, and has the same function. Also in the example of FIG. 15, the first power conversion unit 50 has a first conversion circuit 51 (one conversion unit), a transformer 53, and a second conversion circuit 52 (another conversion unit). The transformer 53 includes a first coil 53A (primary coil) and a second coil 53B (secondary coil) that are magnetically coupled to each other. When an AC voltage is generated in one of the first coil 53A and the second coil 53B, the transformer 53 generates an AC voltage corresponding to the AC voltage in the other. The first conversion circuit 51 (one conversion unit) can perform the first operation based on the electric power from the first high voltage battery 54A corresponding to the first conversion circuit 51. In the first operation, the DC voltage applied between the pair of first conductive paths 21A and 21B (a pair of one-side conductive paths) corresponding to the first high-voltage battery 54A is converted into an AC voltage and used in the first coil 53A. This is an operation that generates an AC voltage. The first conversion circuit 51 may perform a second operation of converting an AC voltage generated in the first coil 53A into a DC voltage and applying a DC voltage between the pair of first conductive paths 21A and 21B. The second conversion circuit 52 converts the AC voltage generated in the second coil 53B into a DC voltage, and the DC voltage between the pair of conductive paths 21C and 21D (the pair of conductive paths on the other side) corresponding to the second conversion circuit 52. A third operation can be performed. The second conversion circuit 52 may perform a fourth operation of converting the DC voltage applied between the pair of conductive paths 21C and 21D to generate an AC voltage in the second coil 53B. The conductive path 21C is a conductive path that short-circuits with the third conductive path 23A when the blocking portion 91 is in the ON state. The conductive path 21D is a conductive path short-circuited with the third conductive path 23B. The conductive path 21D is a conductive path electrically connected to the ground.

A second conductive path 22A (third wiring section) is provided between the high potential side electrode (the electrode having the highest potential) of the second high voltage battery 34B (second battery section) and the third terminal 373. A second conductive path 22B (fourth wiring portion) is provided between the low-potential side electrode (the electrode having the smallest potential) of the second high-voltage battery 34B and the fourth terminal 374. The third terminal 373 may be electrically connected to the high potential side electrode of the second high voltage battery 34B via the second conductive path 22A. The third terminal 373 may always be short-circuited to the high potential side electrode of the second high voltage battery 34B via the second conductive path 22A. Alternatively, a switch may be interposed in the second conductive path 22A. In this case, when the switch of the second conductive path 22A is in the ON state, the third terminal 373 has a high potential of the second high voltage battery 34B. It may be short-circuited to the side electrode. The fourth terminal 374 may be electrically connected to the low potential side electrode of the second high voltage battery 34B via the second conductive path 22B. The fourth terminal 374 may always be short-circuited to the low potential side electrode of the second high voltage battery 34B via the second conductive path 22B. Alternatively, a switch may be interposed in the second conductive path 22B. In this case, when the switch of the second conductive path 22B is in the ON state, the fourth terminal 374 has a low potential of the second high voltage battery 34B. It may be short-circuited to the side electrode.

The second conductive paths 22A and 22B are paths to which a voltage based on the voltage across the second high voltage battery 34B is applied. The second power conversion unit 60 converts the voltage applied between the second conductive path 22A on one side and the second conductive path 22B on the other side so as to step down the voltage, and the second conductive path 23A and the third conductive path 23A on the other side. An operation of applying an output voltage to the other third conductive path 23B is performed. The second power conversion unit 60 has the same configuration as the second power conversion unit 60 of the first embodiment shown in FIGS. 1, 2, and the like, and has the same function. Also in the example of FIG. 15, the second power conversion unit 60 has a first conversion circuit 61 (one conversion unit), a transformer 63, and a second conversion circuit 62 (another conversion unit). The transformer 63 includes a first coil 63A (primary coil) and a second coil 63B (secondary coil) that are magnetically coupled to each other. When an AC voltage is generated in one of the first coil 63A and the second coil 63B, the transformer 63 generates an AC voltage corresponding to the AC voltage in the other. The first conversion circuit 61 (one conversion unit) may perform the first operation based on the electric power from the second high voltage battery 54B corresponding to the first conversion circuit 61. In the first operation, the DC voltage applied between the pair of second conductive paths 22A and 22B (a pair of one-side conductive paths) corresponding to the second high-voltage battery 54B is converted into an AC voltage and used in the first coil 63A. This is an operation that generates an AC voltage. The first conversion circuit 61 may perform a second operation of converting an AC voltage generated in the first coil 53A into a DC voltage and applying a DC voltage between the pair of second conductive paths 22A and 22B. The second conversion circuit 62 converts the AC voltage generated in the second coil 53B into a DC voltage, and the DC voltage between the pair of conductive paths 22C and 22D (the pair of conductive paths on the other side) corresponding to the second conversion circuit 62. A third operation can be performed. The second conversion circuit 62 may perform a fourth operation of converting the DC voltage applied between the pair of conductive paths 22C and 22D to generate an AC voltage in the second coil 63B. The conductive path 22C is a conductive path that short-circuits with the third conductive path 23A when the blocking portion 92 is in the ON state. The conductive path 22D is a conductive path short-circuited with the third conductive path 23B.

The power conversion unit 40 has a plurality of cutoff units 91 and 92. Each of the plurality of cutoff units 91 and 92 is provided between each of the first power conversion unit 50 and the second power conversion unit 60 and the third conductive path 23A, respectively. The cutoff unit 91 allows power to be transmitted between the first power conversion unit 50 and the third conductive path 23A via itself when it is in the on state, and allows the first power to be transmitted via itself when it is in the off state. It cuts off the transmission of electric power between the conversion unit 50 and the third conductive path 23A. The blocking unit 91 is composed of FETs 91A and 91B arranged in opposite directions to each other. When both the FETs 91A and 91B are in the off state, the cutoff unit 91 is in the off state. In this case, the energization via the cutoff unit 91 is cut off in both directions. When both the FETs 91A and 91B are in the ON state, the cutoff unit 91 is in the ON state. In this case, energization via the cutoff unit 91 is allowed in both directions. The cutoff unit 92 allows power to be transmitted between the second power conversion unit 60 and the third conductive path 23A via itself when it is in the on state, and allows the second power to be transmitted via itself when it is in the off state. It cuts off the transmission of electric power between the conversion unit 60 and the third conductive path 23A. The blocking unit 92 is composed of FETs 92A and 92B arranged in opposite directions to each other. When both the FETs 92A and 92B are in the off state, the cutoff unit 92 is in the off state. In this case, the energization via the cutoff unit 92 is cut off in both directions. When both the FETs 92A and 92B are in the ON state, the cutoff unit 92 is in the ON state. In this case, energization via the cutoff unit 92 is allowed in both directions.

The first relay section 331 switches between an on state that allows energization between the first conductive path 21A (first wiring section) and the second conductive path 22A (third wiring section) and an off state that cuts off the energization. .. The first relay unit 331 is composed of FETs 331A and 331B arranged in opposite directions to each other. When both the FETs 331A and 331B are in the off state, the first relay unit 331 is in the off state. In this case, the energization via the first relay unit 331 is cut off in both directions. When the first relay section 331 is in the off state, no current flows between the first conductive path 21A and the second conductive path 22A via the first relay section 331. When the first relay portion 331 is in the ON state, the first conductive path 21A and the second conductive path 22A are short-circuited.

The second relay section 332 switches between an on state that permits energization between the first conductive path 21B (second wiring section) and the second conductive path 22B (fourth wiring section) and an off state that cuts off the energization. .. The second relay unit 332 is composed of FETs 332A and 332B arranged in opposite directions to each other. When both the FETs 332A and 332B are in the off state, the second relay unit 332 is in the off state. In this case, the energization via the second relay unit 332 is cut off in both directions. When the second relay section 332 is in the off state, no current flows between the first conductive path 21B and the second conductive path 22B via the second relay section 332. When the second relay portion 332 is in the ON state, the first conductive path 21B and the second conductive path 22B are short-circuited. The FETs 331B and 332B may be omitted.

(Basic operation of converter)
The conversion device 310 of the third embodiment can perform the imbalance suppression operation in the same manner as that of the first embodiment. The control unit 18 shown in FIG. 14 operates the power conversion unit 40 to reduce the difference in output voltage or SOC between the first high-voltage battery 54A and the second high-voltage battery 54B when a predetermined start condition is satisfied. Let me do it. The predetermined start condition can be the same as the predetermined start condition in the first embodiment. Specifically, the conversion device 310 can perform the operation of the first mode, the operation of the second mode, the operation of the third mode, and the operation of the fourth mode in the same manner as in the first embodiment. .. The first operating condition when the conversion device 310 performs the operation of the first mode can be the same as that of the first embodiment, and the operation of the first mode can also be the same as that of the first embodiment. The second operating condition when the conversion device 310 performs the operation of the second mode can be the same as that of the first embodiment, and the operation of the second mode can also be the same as that of the first embodiment. The third operating condition when the conversion device 310 performs the operation of the third mode can be the same as that of the first embodiment, and the operation of the third mode can also be the same as that of the third embodiment. The fourth operating condition when the conversion device 310 performs the operation of the fourth mode can be the same as that of the first embodiment, and the operation of the fourth mode can also be the same as that of the first embodiment. Regardless of which mode the conversion device 310 operates in, the termination condition can be the same as that of the first embodiment.

(Protective operation of converter)
In the present embodiment, the control unit 18 corresponds to an example of the cutoff control unit, and controls the cutoff units 91 and 92. The control unit 18 corresponds to an example of the converter control unit, and controls the first power conversion unit 50 and the second power conversion unit 60. The control unit 18 also functions as a failure detection unit, and detects the failure of each of the first power conversion unit 50 and the second power conversion unit 60. For example, the control unit 18 determines that the first power conversion unit 50 is out of order when the voltage of the conductive path 21C drops below the threshold value when the cutoff unit 91 is in the ON state. Further, the control unit 18 determines that the second power conversion unit 60 is out of order when the voltage of the conductive path 22C drops below the threshold value when the cutoff unit 92 is in the ON state. In this case, the threshold value is lower than the voltage applied between the third conductive paths 23A and 23B when the low-voltage battery 32 is fully charged.

When the control unit 18 (cutoff control unit) detects a failure of either the first power conversion unit 50 or the second power conversion unit 60, the control unit 18 (disconnection control unit) includes the converter and the third conductive path 23A in which the failure is detected. The cutoff portion provided between the two is switched to the off state. Then, when the failure of any of the converters is detected by itself, the control unit 18 (converter control unit) operates the converter in which the failure is not detected.

For example, if the control unit 18 detects a failure of the first power conversion unit 50 and does not detect a failure of the second power conversion unit 60, the control unit 18 switches the cutoff unit 91 to the off state and switches the second power conversion unit 60 to the off state. Make it work. Specifically, when the control unit 18 detects a failure of the first power conversion unit 50 while causing the first power conversion unit 50 and the second power conversion unit 60 to perform the first conversion operation, the first The operation of the power conversion unit 50 can be stopped and the cutoff unit 91 can be switched to the off state, and if the failure of the second power conversion unit 60 is not detected, the second power conversion unit 60 can continue the first conversion operation. .. Similarly, the control unit 18 detects the failure of the second power conversion unit 60, and if the failure of the first power conversion unit 50 is not detected, the control unit 18 switches the cutoff unit 92 to the off state and the first power conversion unit 50. To operate. For example, when the control unit 18 detects a failure of the second power conversion unit 60 while causing the first power conversion unit 50 and the second power conversion unit 60 to perform the first conversion operation, the control unit 18 detects a failure of the second power conversion unit 60. The operation of the 60 can be stopped and the cutoff unit 92 can be switched to the off state, and if the failure of the first power conversion unit 50 is not detected, the first power conversion unit 50 can continue the first conversion operation.

As described above, in the conversion device 310, the blocking portions 91 and 92 are provided between each converter and the third conductive path 23A, respectively. Therefore, if necessary, between each converter and the third conductive path 23A. Can be individually blocked. Then, when any of the converters fails, the conversion device 310 individually cuts off between the failed converter and the third conductive path 23A, and electrically disconnects the failed converter from the third conductive path 23A. be able to. Further, the conversion device 310 can continue the power conversion by operating the converter in which the failure has not occurred while suppressing the influence of the converter in which the failure has occurred.

The control unit 18 corresponds to an example of the relay control unit, and controls the first relay unit 331 and the second relay unit 332. The control unit 18 corresponds to an example of an abnormality detection unit, and detects an abnormality in the power supply from the first high-voltage battery 34A (first battery unit) and an abnormality in the power supply from the second high-voltage battery 34B (second battery unit). To detect. For example, the control unit 18 determines that the power supply from the first high voltage battery 34A is abnormal when the voltage applied between the first conductive paths 21A and 21B is equal to or less than the threshold voltage. The threshold voltage in this case is a value lower than the output voltage (voltage across) of the first high voltage battery 34A at the time of full charge. Similarly, the control unit 18 determines that the power supply from the second high voltage battery 34B is abnormal when the voltage applied between the second conductive paths 22A and 22B is equal to or less than the threshold voltage. The threshold voltage in this case is a value lower than the output voltage (voltage across) of the second high voltage battery 34B at the time of full charge. The control unit 18 switches the first relay unit 331 and the second relay unit 332 to the off state when an abnormality in the power supply from either the first high voltage battery 34A or the second high voltage battery 34B is detected by itself. ..

For example, in the control unit 18, the first power conversion unit 50 performs the first conversion operation or the second conversion in a state where the output voltage (voltage across the ends) of the first high voltage battery 34A is applied between the first conductive paths 21A and 21B. The second power conversion unit 60 performs the first conversion operation or the second conversion operation in a state where the operation is performed and the output voltage (voltage across the ends) of the second high voltage battery 34B is applied between the second conductive paths 22A and 22B. If it is determined that the power supply from either the first high-voltage battery 34A or the second high-voltage battery 34B is abnormal, the first relay unit 331 and the second relay unit 332 are switched to the off state. The operation of the first conversion circuit of the converter corresponding to the battery whose power supply is abnormal is stopped. On the other hand, when the control unit 18 determines that the power supply from either the first high-voltage battery 34A or the second high-voltage battery 34B is not abnormal, the first relay unit 331 and the second relay unit 332 are turned off. While maintaining the operation, the converter corresponding to the battery for which the power supply is determined to be normal is continued to operate.

When the first relay unit 331 and the second relay unit 332 are in the ON state, the conversion device 310 receives power from not only the first high voltage battery 34A but also the second high voltage battery 34B with respect to the first conductive paths 21A and 21B. Be supplied. Further, when the first relay unit 331 and the second relay unit 332 are in the ON state, electric power is supplied to the second conductive paths 22A and 22B not only from the first high voltage battery 34A but also from the second high voltage battery 34B. .. Therefore, both the first power conversion unit 50 and the second power conversion unit 60 can perform power conversion based on the power from both battery units. On the other hand, when the first relay section 331 and the second relay section 332 are in the off state, the space between the first conductive path 21A and the second conductive path 22A is cut off, and the space between the first conductive path 21B and the second conductive path 22B is blocked. It is blocked. Therefore, the second power conversion unit 60 can operate independently while suppressing the influence of the first high voltage battery 34A, and the first power conversion unit 50 can operate independently while suppressing the influence of the second high voltage battery 34B. be able to. Specifically, the conversion device 310 turns off the first relay unit 331 and the second relay unit 332 when the power supply from either the first high-voltage battery 34A or the second high-voltage battery 34B is abnormal. By switching, it is possible to cut off the energization via the first relay unit 331 and the second relay unit 332. Therefore, in this case, the first power conversion unit 50 and the second power conversion unit 60 are electrically separated from each other in the circuit on the battery unit side, and the influence of the battery unit in which the abnormality occurs is affected by the first power conversion unit 50 and the battery unit. It is possible to suppress the influence on both of the second power conversion units 60.

<Fourth Embodiment>
The following description relates to the fourth embodiment.
The conversion device 410 of the fourth embodiment is provided with a transformer 453 in place of the transformers 53 and 63 used in the third embodiment, and the first coils 53A and 63A and the second coils 53B and 63B are magnetically coupled. Only is different from the third embodiment, and other points are the same as the third embodiment. In the converter 410, the transformer 453 is configured by integrating the transformer 53 of the first power conversion unit 50 (one converter) and the transformer 63 of the second power conversion unit 60 (another converter) in a plurality of converters. Has been done. The transformer 453 has a first coil 53A (primary coil) and a second coil 53B (secondary coil) in the transformer 53, and a first coil 63A (primary coil) and a second coil 63B (secondary coil) in the transformer 63. The coil) is magnetically coupled.

The conversion device 410 includes all the configurations of the conversion device 310 except for the transformer 453. The conversion device 410 can perform the same operation as that of the conversion device 310.

Further, in the conversion device 410, the control unit 18 (converter control unit) is the second conversion circuit 52, 62 (other) of the first power conversion unit 50 (one converter) and the second power conversion unit 60 (other converter). In a state where the operation of the conversion unit) is stopped, the above-mentioned first operation is performed on the first conversion circuit (one conversion unit) of either the first power conversion unit 50 or the second power conversion unit 60. The conversion control may be performed so that the other first conversion circuit (one conversion unit) performs the above-mentioned second operation. The first operation described above is an operation of converting a DC voltage based on the power from the corresponding battery into an AC voltage to generate an AC voltage in the primary coil. The second operation described above is an operation of converting an AC voltage generated in the primary coil into a DC voltage and applying a DC voltage between the pair of one-side conductive paths.

For example, when the value of either the output voltage or the SOC of the first high-voltage battery 54A is larger than a certain value or more than the value of the index in the second high-voltage battery 54B, the control unit 18 uses the second conversion circuit 52, With the operation of 62 stopped, the first conversion circuit 51 of the first power conversion unit 50 performs the first operation, and the first conversion circuit 61 of the second power conversion unit 60 performs the second operation. The conversion control may be performed so as to be performed. By doing so, with the operations of the second conversion circuits 52 and 62 stopped, the first high-voltage battery 54A can be discharged and the second high-voltage battery 54B can be charged to reduce the difference in the above indexes. can. Similarly, when the value of either the output voltage or the SOC of the second high-voltage battery 54B is larger than a certain value or more than the value of the index in the first high-voltage battery 54A, the operation of the second conversion circuits 52 and 62 is performed. In the stopped state, the first conversion circuit 61 of the second power conversion unit 60 performs the above-mentioned first operation, while the first conversion circuit 51 of the first power conversion unit 50 performs the above-mentioned second operation. The conversion control may be performed so as to be performed. By doing so, it is possible to discharge from the second high-voltage battery 54B and charge the first high-voltage battery 54A in a state where the operations of the second conversion circuits 52 and 62 are stopped to reduce the difference in the above indexes. ..

<Fifth Embodiment>
The following description relates to the fifth embodiment.
The conversion device of the fifth embodiment includes all the configurations of any of the conversion devices 10, 210, and 310 of the first to third embodiments, and further features are added.

The conversion devices 10, 210, and 310 of the first to third embodiments described above correspond to the control unit 18 that controls the power conversion unit (power conversion unit 40 or power conversion unit 240) and an example of the switching circuit. It has a switch unit 14 to control the switch unit 14 and a control unit 18 to control the switch unit 14 (switching circuit). The control unit 18 corresponds to an example of a switching control unit. The power supply systems 3, 203, 303 in which these conversion devices 10, 210, and 310 are used are a pair of power paths 28A, which are paths for transmitting electric power to a drive unit 4 provided in a vehicle 1 on which the power supply system is mounted. , 28B. The drive unit 4 corresponds to an example of a load. The switch unit 14 (switching circuit) switches between a state in which a plurality of batteries (first high-voltage battery 34A, second high-voltage battery 34B) are connected in series between a pair of power paths 28A and 28B and a state in which they are connected in parallel. It has a structure.

The features of the fifth embodiment described below can be applied to any of the conversion devices 10, 210, and 310 of the first to third embodiments. In the following, an example in which the following features are added to the conversion device 10 of the first embodiment will be described as a representative example. Since the representative example of the fifth embodiment includes all the features of the conversion device 10 of the first embodiment, FIGS. 1 to 8 are appropriately referred to below.

The conversion device 10 of the representative example of the fifth embodiment has the configuration as shown in FIG. In this conversion device 10, the control unit 18 (switching control unit), for example, inserts a plurality of batteries (first high-voltage battery 34A, second high-voltage battery 34B) between a pair of power paths 28A and 28B while the vehicle 1 is traveling. The switch unit 14 (switching circuit) is controlled so as to switch between a state of being connected in series and a state of being connected in parallel. When the control unit 18 (switching control unit) switches a plurality of the batteries between the series connection state and the parallel connection state while the vehicle 1 is running, the control unit 18 (switching control unit) switches the plurality of batteries in parallel with the series connection state according to the running state of the vehicle 1. You may switch to the connected state. As a method of switching according to the traveling state of the vehicle 1, for example, when the speed of the vehicle 1 exceeds a predetermined speed, the connection state is switched to the series connection state, and when the speed of the vehicle 1 is equal to or less than the predetermined speed, the connection state is changed to the parallel connection state. It may be a method of switching. Alternatively, as a method of switching according to the traveling state of the vehicle, a method of switching to a series connection state when the vehicle 1 is traveling in a predetermined area and switching to a parallel connection state when traveling outside the predetermined area. It may be. Alternatively, the method of switching according to the traveling state of the vehicle 1 is to switch to the series connection state when the sum of the output voltages of the first high voltage battery 34A and the second high voltage battery 34B is less than a certain value, and is equal to or more than a certain value. Sometimes it may be a method of switching to the parallel connection state. Alternatively, the method of switching according to the traveling state of the vehicle 1 is a method of switching to a parallel connection state from the start of the vehicle 1 until a predetermined condition is satisfied, and then switching to a series connection state after the predetermined condition is satisfied. May be good.

When operating in this way, from the first high-voltage battery 34A and the second high-voltage battery 34B connected in series while connecting the first high-voltage battery 34A and the second high-voltage battery 34B in series between the pair of power paths 28A and 28B. With the control unit 18 controlling the switch unit 14 so as to supply power to the drive unit 4 (load), the control unit 18 has at least one of the first conversion operation and the second conversion operation with respect to the power conversion unit 40. May be done. For example, when the first high-voltage battery 34A and the second high-voltage battery 34B are switched to the series connection state while the vehicle 1 is running, the control unit 18 is in the running and series connection state (that is, connected in series) of the vehicle 1. In the state where power is supplied to the drive unit 4 (load) from the first high-voltage battery 34A and the second high-voltage battery 34B), the power conversion unit 40 is made to perform at least one of the first conversion operation and the second conversion operation. It may be controlled as follows. When the control unit 18 controls the power conversion unit 40 in the series connection state while the vehicle is traveling, the power conversion unit 40 may be operated in any of the first to fourth modes. Which of the first to fourth modes the power conversion unit 40 is operated can be selected by the same method as in the first embodiment.

<Sixth Embodiment>
The following description relates to the sixth embodiment.
The conversion device of the sixth embodiment includes all the configurations of any one of the conversion devices 10, 210, 310, 410 of the first to fifth embodiments, and further features are added. The power supply systems 3, 203, 303, and 403 in which the conversion devices 10, 210, 310, and 410 of the first to fifth embodiments are used supply electric power to the drive unit 4 provided in the vehicle 1 on which the power supply system is mounted. It has a pair of power paths 28A and 28B that are transmission paths. The drive unit 4 corresponds to an example of a load.

The conversion devices 10, 210, 310, and 410 of the first to fifth embodiments all include a control unit 18 that controls a power conversion unit (power conversion unit 40 or power conversion unit 240) and a plurality of batteries (first high voltage). A state in which a part of the battery 34A and the second high-voltage battery 34B) (specifically, one of the first high-voltage battery 34A and the second high-voltage battery 34B) is connected between the pair of power paths 28A and 28B. , A switching circuit that switches between a plurality of batteries (first high-voltage battery 34A, second high-voltage battery 34B) connected in parallel between a pair of power paths 28A and 28B, and a switching control unit that controls the switching circuit. (Control unit 18). When the function of the sixth embodiment is applied to any of the conversion devices 10, 210, and 310 of the first to third and fifth embodiments, the switch unit 14 corresponds to an example of the switching circuit. When the function of the sixth embodiment is applied to the conversion device 410 of the fourth embodiment, the relays 393A and 393B correspond to an example of the switching circuit.

The features of the sixth embodiment described below can be applied to any of the conversion devices 10, 210, 310, 410 of the first to fifth embodiments.

The conversion device of the sixth embodiment has a first feature that it has an abnormality detection unit that detects a battery in which an abnormality in power supply has occurred from among a plurality of batteries (first high voltage battery 34A, second high voltage battery 34B). Be prepared. Further, in the conversion device of the sixth embodiment, when an abnormality in the power supply of any one of the plurality of batteries (first high-pressure battery 34A, second high-pressure battery 34B) is detected by the abnormality detection unit, the conversion device has a plurality of batteries (first high-pressure battery 34A, second high-pressure battery 34B). The switching control unit has a second feature that a battery in which an abnormality in power supply is not detected is connected between a pair of power paths 28A and 28B. Further, in the conversion device of the sixth embodiment, the switching control unit connects a plurality of batteries (first high voltage battery 34A, second high voltage battery 34B) in parallel between the pair of power paths 28A and 28B while the vehicle is traveling. It has a third feature that it is possible to do so. Further, in the conversion device of the sixth embodiment, when the abnormality of the power supply of any of the batteries is detected by the abnormality detection unit while the vehicle is running, the switching control unit does not detect the abnormality of the power supply. It has a fourth feature that the battery is connected between the pair of power lines 28A and 28B.

In the following, an example in which the following features are added to the conversion device 10 of the first embodiment will be described as a representative example. Since the representative example of the sixth embodiment includes all the features of the conversion device 10 of the first embodiment, FIGS. 1 to 8 are appropriately referred to below. The conversion device 10 of the representative example of the sixth embodiment has the configuration as shown in FIG. The conversion device 10 determines, for example, whether or not the management device 17 corresponds to an example of the abnormality detection unit, and whether or not an abnormality in the power supply has occurred in either the first high-voltage battery 34A or the second high-voltage battery 34B. In a typical example, the "abnormal power supply" is "the output voltage of either the first high voltage battery 34A or the second high voltage battery 34B is equal to or less than the threshold voltage". However, the "abnormality of power supply" may be, for example, "the SOC of either the first high voltage battery 34A or the second high voltage battery 34B is equal to or less than the threshold value", or may be another abnormality. ..

The conversion device 10 controls when the abnormality detection unit (management device 17) detects that the output voltage of any one of the first high-voltage battery 34A and the second high-voltage battery 34B is equal to or lower than the threshold voltage. The unit 18 (switching control unit) switches the switch unit 14 (switching circuit) so as to connect a battery in which an abnormality in the power supply has not been detected between the pair of power paths 28A and 28B. The abnormality detection by the abnormality detection unit and the switching operation by the switching circuit may be performed while the vehicle is running, or may be performed during a period other than the running.

For example, the control unit 18 (switching control unit) can connect the first high-voltage battery 34A and the second high-voltage battery 34B in parallel between the pair of electric power paths 28A and 28B while the vehicle is running, and the parallel connection thereof. In this state, it is possible to supply electric power to the drive unit 4 (load) from the first high-voltage battery 34A and the second high-voltage battery 34B. In the conversion device 10, when the abnormality detection unit (management device 17) detects that the output voltage of either the first high-voltage battery 34A or the second high-voltage battery 34B is equal to or lower than the threshold voltage while the vehicle is running. In addition, the battery in which the output voltage is detected to be below the threshold voltage is electrically cut off from the pair of power paths 28A and 28B (conduction is cut off), and it is not detected that the output voltage is below the threshold voltage. The switch unit 14 (switching circuit) is operated so as to maintain the state in which the battery is electrically connected to the pair of power paths 28A and 28B (maintain the conduction state). For example, the control unit 18 supplies power to the drive unit 4 (load) in a state where the first high voltage battery 34A and the second high voltage battery 34B are connected in parallel between the pair of power paths 28A and 28B while the vehicle is running. When the abnormality detection unit (management device 17) detects that the output voltage of the first high-voltage battery 34A is equal to or lower than the threshold voltage, the first high-voltage battery 34A is connected to the pair of power paths 28A. , 28B is electrically cut off, and a switch is used to maintain the state in which the second high-voltage battery 34B, whose output voltage is not detected to be below the threshold voltage, is electrically connected to the pair of power paths 28A and 28B. The unit 14 (switching circuit) is operated.

<Other embodiments>
The present disclosure is not limited to the embodiments described above with reference to the description and drawings. For example, the features of the embodiments described above or below can be combined in any combination within a consistent range. Further, any of the features of the above-mentioned or later-described embodiments may be omitted unless it is clearly stated as essential. Further, the above-described embodiment may be modified as follows.

In the above-described embodiment, the control unit 18 is included in the conversion device, but the control unit may not be included in the conversion device. That is, the control unit may be configured as a device different from the conversion device.

In the above-described embodiment, the switch unit 14 is included in the conversion device, but the switch unit 14 may not be included in the conversion device. That is, the switch unit 14 may be configured as a device different from the conversion device.

In the above-described embodiment, the management device 17 is included in the conversion device, but the management device 17 may not be included in the conversion device. That is, the management device 17 may be configured as a device different from the conversion device.

The power conversion units 40 and 240 could perform the second conversion operation so as to individually output power to all the batteries among the plurality of batteries, but the present invention is not limited to this example. The power conversion unit may perform power conversion in both directions so as to individually output power to only a part of the plurality of batteries.

In the above-described embodiment, the conversion devices 10 and 210 perform an imbalance suppression operation so as to reduce the difference in output voltage when the above-mentioned start condition is satisfied, but the present invention is not limited to this example. When the above-mentioned start conditions are satisfied, the conversion devices 10 and 210 may perform an imbalance suppression operation so as to reduce the difference in SOC (State Of Charge). In this case, in the above-described embodiment, the battery having a relatively high output voltage among the plurality of batteries is replaced with the battery having a relatively high SOC among the plurality of batteries, and the output voltage among the plurality of batteries is relatively high. The low battery may be replaced with a battery having a relatively low SOC among a plurality of batteries. In this case, the control unit 18 may perform the imbalance suppression operation when the absolute value of the difference in SOCs of the plurality of batteries is equal to or greater than the threshold value. When the power conversion unit 40 is to perform the imbalance suppression operation, the control unit 18 sets the battery having the larger SOC among the plurality of batteries in the discharged state or the charge stop state, and charges the battery having the smaller SOC. May cause the power conversion unit 40 to perform power conversion. Then, the control unit 18 may end the imbalance suppression operation when the absolute value of the difference between the SOCs of the plurality of batteries becomes a certain value or less, which is smaller than the above threshold value.

When the control unit 18 performs the imbalance suppression operation, the power conversion unit 40, so that the charging current supplied to the battery having the smaller output voltage or SOC is larger than the charging current supplied to the battery having the larger SOC. The 240 may be made to perform power conversion.

In the above-described embodiment, two batteries are provided as a plurality of batteries, but three or more batteries may be provided. In this case, each converter may be provided for each battery. In the second embodiment, two batteries are provided as a plurality of batteries, but three or more batteries may be provided. In this case, each first conversion unit may be provided for each battery. In this case, the transformer may be provided with three or more first coils, and each first coil may be provided corresponding to each first conversion unit.

In any of the above-described embodiments, the third operating condition may be "the output voltage of the low voltage battery 32 is equal to or higher than the threshold voltage". Alternatively, the third operating condition is that "the output voltage of the low voltage battery 32 is equal to or higher than the threshold voltage" and "the SOC of the battery having the larger output voltage (the first high voltage battery 34A in the examples of FIGS. 7 and 13) is less than a predetermined value. May be.

In the description of the third embodiment, an example in which the control unit 18 functions as a failure detection unit is shown, but the failure detection method is not limited to the above example. For example, if the current flowing through the conductive path 21C in the first power conversion unit 50 is equal to or greater than the overcurrent threshold value, or if the voltage of the conductive path 21C is equal to or greater than the overvoltage threshold value, the first power conversion unit 50 is out of order. The determination may be made and the cutoff unit 91 may be turned off. Similarly, when the current flowing through the conductive path 22C in the second power conversion unit 60 is equal to or greater than the overcurrent threshold value, or when the voltage of the conductive path 22C is equal to or greater than the overvoltage threshold value, the second power conversion unit 60 is out of order. It may be determined that the cutoff unit 92 is turned off.

In the description of the third embodiment, an example in which the control unit 18 functions as an abnormality detection unit is shown, but the abnormality detection method is not limited to the above example. For example, the control unit 18 may determine that the power supply from the first high voltage battery 54A is abnormal when the SOC or output voltage of the first high voltage battery 54A is less than a predetermined value. Similarly, when the SOC or output voltage of the second high voltage battery 54B is less than a predetermined value, it may be determined that the power supply from the second high voltage battery 54B is abnormal.

In the third embodiment, the power conversion unit 40 is used in the conversion device 310, but the power conversion unit 240 in the second embodiment may be used instead of the power conversion unit 40. When the power conversion unit 240 is used in the conversion device 310 in this way, the conversion device 310 causes the power conversion unit 240 to perform the same operation as the operation performed by the power conversion unit 240 in the conversion device 210 of the second embodiment. May be good.

It should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is not limited to the embodiments disclosed here, but includes all modifications within the scope indicated by the claims or within the scope equivalent to the claims. Is intended.

1: Vehicles 3, 203, 303: Power supply system 4: Drive unit (load)
10, 210, 310, 410: Conversion device 14: Switch section (switching circuit)
18: Control unit (cutoff control unit, converter control unit, failure detection unit, relay control unit, abnormality detection unit, switching control unit)
21A: First conductive path (first wiring section)
21B: First conductive path (second wiring section)
22A: 2nd conductive path (3rd wiring section)
22B: 2nd conductive path (4th wiring section)
23A: Third conductive path (conductive path)
23B: Third conductive path (conductive path)
28A, 28B: Power path 32: Low voltage battery (second battery)
34: High voltage battery 34A: First high voltage battery (battery, first battery section)
34B: 2nd high voltage battery (battery, 2nd battery part)
40, 240: Power conversion unit 50: First power conversion unit (converter, first converter)
51: First conversion circuit (first conversion unit of one)
52: Second conversion circuit (other first conversion unit)
53: Transformer 53A: First coil 53B: Second coil 60: Second power converter (converter, second converter)
61: 1st conversion circuit 62: 2nd conversion circuit 63: Transformer 63A: 1st coil 63B: 2nd coil 91, 92: Blocking unit 241A: 1st conversion unit 241B: 1st conversion unit 242: 2nd conversion unit 243 : Transformer 243A: 1st coil 243B: 1st coil 243C: 2nd coil 331: 1st relay section 332: 2nd relay section

Claims (22)

1. A converter used in power systems where multiple batteries can be connected at least in parallel.
   It has a power conversion unit that performs a first conversion operation that converts the power input from each of the batteries and outputs the power to a conductive path different from that of the battery.
   The power conversion unit is a conversion device that performs a second conversion operation that individually outputs power to at least one of the batteries.
2. The power conversion unit includes a plurality of converters and has a plurality of converters.
   Each said converter is provided corresponding to each said battery, respectively.
   The conversion device according to claim 1, wherein at least one of the plurality of converters performs power conversion in both directions.
3. The first power conversion unit outputs power to the conductive path based on the power supplied from one battery by at least one of the converters in response to a partial charging instruction from the outside. The conversion device according to claim 2, wherein the conversion operation is performed, and the second conversion operation is performed so that the other converter outputs electric power to the other battery based on the electric power supplied from the conductive path.
4. The conductive path is electrically connected to a plurality of second batteries different from the battery.
   The power conversion unit stops the conversion operation of one of the converters in response to a partial stop instruction from the outside, and the other converter is based on the power supplied from the second battery to the other battery. The conversion device according to claim 2 or 3, wherein the second conversion operation is performed so as to output electric power to.
5. The power conversion unit has a plurality of cutoff units and has a plurality of cutoff units.
   Each of the cutoffs is provided between each of the converters and the conductive path, respectively.
   The cutoff allows power to be transmitted between the converter and the conductive path through itself when in the on state, and between the converter and the conductive path via itself when in the off state. The conversion device according to any one of claims 2 to 4, wherein the transmission of electric power is cut off.
6. A cutoff control unit that controls a plurality of the cutoff units,
   A converter control unit that controls a plurality of the converters,
   A failure detection unit that detects the failure of each of the plurality of converters,
   Have,
   When the failure detection unit detects a failure of any of the converters, the cutoff control unit turns off the cutoff unit provided between the converter where the failure is detected and the conductive path. switching,
   The conversion device according to claim 5, wherein the converter control unit operates the converter in which the failure is not detected when the failure detection unit detects the failure of any of the converters.
7. The plurality of batteries include a first battery unit and a second battery unit.
   The plurality of converters include a first converter and a second converter.
   Between the first battery unit and the first converter, a first wiring unit and a second wiring unit, which are paths to which a voltage based on the voltage across the first battery unit is applied, are provided.
   Between the second battery unit and the second converter, a third wiring unit and a fourth wiring unit, which are paths to which a voltage based on the voltage across the second battery unit is applied, are provided.
   The first converter performs an operation of converting a voltage applied between the first wiring portion and the second wiring portion and applying an output voltage to the conductive path.
   The second converter performs an operation of converting a voltage applied between the third wiring portion and the fourth wiring portion and applying an output voltage to the conductive path.
   Further, a first relay unit that switches between an on state that permits energization between the first wiring unit and the third wiring unit and an off state that cuts off energization, and the second wiring unit and the fourth wiring unit. The conversion device according to any one of claims 2 to 6, comprising a second relay unit that switches between an on state that permits energization and an off state that cuts off energization.
8. The power conversion unit includes a plurality of first conversion units, a transformer, and a second conversion unit.
   The transformer includes a plurality of first coils and a second coil, and the plurality of the first coils and the second coil are magnetically coupled to each other.
   Each of the first coils is provided corresponding to each of the first conversion units.
   Each of the first conversion units converts DC power based on the power from each of the batteries and outputs AC power to each of the first coils.
   The conversion device according to claim 1, wherein at least one of the first conversion units performs power conversion in both directions.
9. The power conversion unit performs power conversion by the plurality of first conversion units and the transformer based on the power supplied from at least one of the batteries in response to a partial charge instruction from the outside, and the other The conversion device according to claim 8, wherein the second conversion operation is performed so as to supply electric power to the battery.
10. The conductive path is electrically connected to a plurality of second batteries different from the battery.
    The power conversion unit stops the conversion operation of one of the first conversion units in response to a partial stop instruction from the outside, while the other first conversion unit, the transformer, and the second conversion unit The conversion device according to claim 8 or 9, wherein the second conversion operation is performed so as to output electric power to another battery based on the electric power supplied from the second battery.
11. The plurality of batteries include a first battery unit and a second battery unit.
    The plurality of first conversion units include one said first conversion unit and another said first conversion unit.
    Between the first battery unit and the first conversion unit, a first wiring unit and a second wiring unit, which are paths to which a voltage based on the voltage across the first battery unit is applied, are provided.
    Between the second battery unit and the other first conversion unit, a third wiring unit and a fourth wiring unit, which are paths to which a voltage based on the voltage across the second battery unit is applied, are provided.
    The first conversion unit performs an operation of converting a voltage applied between the first wiring unit and the second wiring unit to generate an AC voltage in the first coil.
    The other first conversion unit performs an operation of converting the voltage applied between the third wiring unit and the fourth wiring unit to generate an AC voltage in the other first coil.
    A first relay unit that switches between an on state that permits energization between the first wiring unit and the third wiring unit and an off state that cuts off energization, and the second wiring unit and the fourth wiring unit. The conversion device according to any one of claims 8 to 10, further comprising a second relay unit that switches between an on state that permits energization and an off state that cuts off energization.
12. A relay control unit that controls the first relay unit and the second relay unit,
    An abnormality detection unit that detects an abnormality in the power supply from the first battery unit and an abnormality in the power supply from the second battery unit.
    Have,
    The relay control unit sets the first relay unit and the second relay unit when an abnormality in power supply from either the first battery unit or the second battery unit is detected by the abnormality detection unit. The conversion device according to claim 7 or 11, which switches to the off state.
13. The conductive path is electrically connected to a plurality of second batteries different from the battery.
    When a predetermined condition is satisfied, the power conversion unit performs power conversion based on the power from the second battery, and outputs the power individually to at least one of the batteries. The conversion device according to any one of claims 1 to 12, which operates.
14. A control unit that controls the power conversion unit is provided.
    According to claim 1, the control unit causes the power conversion unit to perform an operation of reducing the difference between the output voltages or SOCs (State Of Charge) of a plurality of the batteries when a predetermined start condition is satisfied. Item 12. The conversion device according to any one of items 13.
15. The conversion device according to any one of claims 1 to 14, wherein the power supply system is a system in which a plurality of the batteries are switched between series connection and parallel connection.
16. The conversion device according to any one of claims 1 to 14, wherein the power supply system is a system in which a plurality of the batteries are connected in parallel and does not switch to series connection.
17. A control unit that controls the power conversion unit and
    Switching circuit and
    A switching control unit that controls the switching circuit and
    Have,
    The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system.
    The switching circuit switches between a state in which a plurality of the batteries are connected in series between the pair of power paths and a state in which the plurality of batteries are connected in parallel.
    In a state where the switching control unit controls the switching circuit so as to supply power to the load from the plurality of batteries connected in series while connecting the plurality of batteries in series between the pair of power paths. The conversion device according to any one of claims 1 to 15, wherein the control unit causes the power conversion unit to perform at least one of the first conversion operation and the second conversion operation.
18. Switching circuit and
    A switching control unit that controls the switching circuit and
    Have,
    The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system.
    The switching circuit switches between a state in which a plurality of the batteries are connected in series between the pair of power paths and a state in which the plurality of batteries are connected in parallel.
    The switching control unit controls the switching circuit so as to switch between a state in which a plurality of the batteries are connected in series and a state in which they are connected in parallel between a pair of electric power paths while the vehicle is traveling. The conversion device according to any one of claims 15 and 17.
19. The conversion device according to claim 18, wherein the switching control unit switches a plurality of the batteries into a series connection state and a parallel connection state according to the traveling state of the vehicle while the vehicle is traveling.
20. The switching control unit switches between a state in which a plurality of the batteries are connected in series between the pair of electric power paths and a state in which the batteries are connected in parallel according to the traveling state of the vehicle while the vehicle is traveling.
    A claim that the control unit causes the power conversion unit to perform at least one of the first conversion operation and the second conversion operation when at least a plurality of the batteries are connected in series while the vehicle is running. 17. The conversion device according to 17.
21. Switching circuit and
    A switching control unit that controls the switching circuit and
    An abnormality detection unit that detects a battery in which an abnormality in power supply has occurred from among the plurality of batteries,
    Have,
    The power supply system has a pair of power paths that are paths for transmitting power to a load provided in a vehicle equipped with the power supply system.
    The switching circuit switches between a state in which a part of the plurality of batteries is connected between the pair of power paths and a state in which the plurality of batteries are connected in parallel between the pair of power paths.
    When the abnormality of the power supply of any of the batteries is detected by the abnormality detection unit, the switching control unit places the battery in which the abnormality of the power supply is not detected between the pair of power paths. The conversion device according to any one of claims 1 to 20 to be connected.
22. The switching control unit can connect a plurality of the batteries in parallel between the pair of electric power paths while the vehicle is traveling.
    When the abnormality of the power supply of any of the batteries is detected by the abnormality detection unit while the vehicle is running, the switching control unit sets a pair of the batteries in which the abnormality of the power supply is not detected. The conversion device according to claim 21, which is connected between the power paths.

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