JP2024016579A - power supply system - Google Patents

Abstract

An object of the present invention is to enable highly efficient power feeding via a transformer while suppressing the generation of leakage magnetic flux as much as possible. This power supply system 10 is arranged between a transformer 11, a primary circuit 12, a secondary circuit 13, a secondary battery 14, and between the secondary circuit 13 and the secondary battery 14. a second relay 16 disposed between the secondary circuit 13 and the first relay 15, a voltage measurement section 16 that measures the voltage of the secondary circuit 13, and a control section 17. Equipped with. The control unit 17 controls the voltage of the secondary circuit 13 measured by the voltage measurement unit 17 when the first relay 15 is turned off, the second relay 16 is turned on, and a predetermined current is supplied from the primary circuit 12. The positional relationship between the primary coil 20 and the secondary coil 21 is evaluated based on the change over time. [Selection diagram] Figure 2

Description

The present invention relates to a power supply system, and particularly to a technique for supplying power via a transformer.

For example, as a non-contact charger that charges secondary batteries such as lithium-ion batteries without contact, there is a known power supply system that transmits power from the power transmitting side to the power receiving side via a transformer (for example, patented (See Document 1 and Patent Document 2).

Japanese Patent Application Publication No. 2011-205829 Japanese Patent Application Publication No. 2016-152687

By the way, in this type of power feeding system, the positional relationship between the power transmitting side coil and the power receiving side coil that constitute the transformer is important in improving the power feeding efficiency. In addition, depending on the positional relationship between the coils on the power transmitting side and the coils on the power receiving side, leakage magnetic flux may occur, which may cause malfunction or other adverse effects on surrounding electronic equipment. Relationships need to be managed properly. This kind of problem becomes more noticeable when the core around which each coil is wound is divided. That is, as described in Patent Document 1, when a device (for example, a charging station) in which a power transmission side coil is provided and a device (for example, a vehicle) in which a power reception side coil is provided are relatively movable, the positional relationship between both coils is changes each time, so it is important to suppress magnetic flux leakage due to positional deviation as much as possible.

For example, Patent Document 2 discloses that by detecting leakage magnetic flux that fluctuates depending on the relative position of the power transmitting side coil and the power receiving side coil, and notifying the driver etc. based on the detection result, the driver etc. can install it in the vehicle. Disclosed is a method for suitably determining the position of the power receiving coil. However, with this method, if there is a problem with the positional relationship between the coils, an unacceptable level of leakage flux will still occur.

In view of the above circumstances, the technical problem to be solved in this specification is to enable highly efficient power supply via a transformer while suppressing the generation of leakage magnetic flux as much as possible.

The solution to the above problem is achieved by a power feeding system according to the present invention. In other words, this power supply system includes a transformer having a primary coil and a secondary coil, a primary circuit that controls the current flowing through the primary coil, and a secondary circuit that controls the current flowing through the secondary coil. , a secondary battery connected to the secondary circuit, a first relay disposed between the secondary circuit and the secondary battery, and a first relay disposed between the secondary circuit and the first relay. a second relay that measures the voltage of the secondary circuit, a voltage measurement section that measures the voltage of the secondary circuit, and a control section, the control section turns off the first relay, turns on the second relay, and supplies a predetermined current to the primary circuit. It is characterized in that the positional relationship between the primary coil and the secondary coil is evaluated based on the change over time in the voltage of the secondary circuit measured by the voltage measurement unit when supplied from the side circuit.

The present inventor focused on the temporal change in the voltage that occurs in the secondary circuit when the power supply to the secondary battery is cut off, and established a predetermined relationship between this temporal change and the positional relationship of each coil of the transformer. I found out that there is. The present invention has been made based on the above findings, and includes connecting a second relay between the secondary circuit and the first relay in addition to the primary relay that switches the connection between the secondary circuit and the secondary battery. , evaluate the positional relationship between the primary coil and the secondary coil based on the change in voltage of the secondary circuit over time when power is supplied with the second relay turned on and the first relay turned off. I did it like that. In this way, it is possible to carry out power supply for evaluating the positional relationship of the coils under conditions (for example, short time, low current, etc.) that are less strict than the power supply conditions when supplying (charging) power to the secondary battery. Even if the relative position deviates from the normal position, leakage of magnetic flux that occurs at that time can be reduced. As described above, according to the present invention, it is possible to efficiently feed power through a transformer while suppressing leakage magnetic flux.

Further, in the power supply system according to the present invention, when the control unit determines that the positional relationship between the primary coil and the secondary coil is in an allowable state, the control unit turns off the second relay and turns on the first relay. Then, charging of the secondary battery may be started.

If charging of the secondary battery is started when it is determined that the positional relationship between the primary coil and the secondary coil is in an acceptable state, the coils will always be properly aligned. Since charging can be started in the same state, highly efficient charging can be carried out stably.

Furthermore, in the power supply system according to the present invention, the predetermined current may be smaller than the current supplied from the primary circuit when charging the secondary battery.

The predetermined current in the present invention is a current set at the time of power supply to evaluate the positional relationship between the primary coil and the secondary coil, so there is no need to set it to a large value unlike when charging. In other words, even if the current is smaller than that during charging, the positional relationship between both coils can be appropriately evaluated by understanding the change over time in the voltage applied to the secondary circuit. It is preferable that the current is small because the amount of leakage of magnetic flux that occurs when the relative positions of the coils are deviated is also small.

Furthermore, in the power feeding system according to the present invention, the primary coil may be provided at the charging station, and the secondary coil may be mounted on the vehicle. In that case, if the control unit determines that the positional relationship between the primary coil and the secondary coil is not in an acceptable state, the control unit moves the secondary coil to a position where the positional relationship is acceptable. Good too.

When considering applying the power supply system according to the present invention to a vehicle charging system, if the control unit determines that the positional relationship between the primary coil and the secondary coil is not in an acceptable state, By moving the secondary coil to a position where the positional relationship is acceptable, it is possible to quickly and appropriately eliminate misalignment between the coils and perform highly efficient charging. . In this case, the secondary coil can be easily and quickly moved by moving the vehicle on which the secondary coil is mounted.

As described above, according to the power feeding system according to the present invention, highly efficient power feeding via a transformer is possible while suppressing the generation of leakage magnetic flux as much as possible. Therefore, when the object of power supply is a secondary battery, highly efficient charging is possible.

1 is a diagram showing the overall configuration of a power feeding system according to an embodiment of the present invention. 2 is a flowchart showing an example of a method for feeding power to a secondary battery using the power feeding system shown in FIG. 1. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a power supply system according to an embodiment of the present invention and a method of supplying power to a secondary battery using this power supply system will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of a power supply system 10 according to an embodiment of the present invention. In this embodiment, this power supply system 10 is for charging a vehicle, and includes a transformer 11 , a primary circuit 12 located on the primary side of the transformer 11 , and a secondary circuit located on the secondary side of the transformer 11 . A circuit 13 , a secondary battery 14 connected to the secondary circuit 13 , a first relay 15 disposed between the secondary circuit 13 and the secondary battery 14 , and a first relay 15 connected to the secondary circuit 13 and the secondary battery 14 . It includes a second relay 16 connected between the first relay 15, a voltage measurement unit 17 that measures the voltage of the secondary circuit 13, and a BMU 18. Here, the BMU 18 corresponds to a control unit according to the present invention. Hereinafter, after explaining the details of each element, an example of how to use the power supply system 10 (that is, a power supply method) will be described.

The transformer 11 has a primary coil 20 wound around a core 19 and a secondary coil 21. In this embodiment, the core 19 is composed of a pair of split cores 22 and 23 called a UU core, and the primary coil 20 is wound around the primary split core (first split core 22), and the secondary coil 20 is wound around the primary split core (first split core 22). The secondary coil 21 is wound around the divided core (second divided core 23). The primary coil 20 is connected to the primary circuit 12 , and the secondary coil 21 is connected to the secondary circuit 13 .

Note that although FIG. 1 shows an example in which the coils 20 and 21 are wound around the bottoms 22a and 23a of the split cores 22 and 23, both of which are U-shaped, the winding positions of the respective coils 20 and 21 are different from each other. is not limited to the bottom portions 22a and 23a. For example, although not shown, the coils 20 and 21 may be wound around a pair of butt portions 22b and 23b that are bent from both ends of the bottom portions 22a and 23a and extend in the same direction.

Of course, the form of the core 19 is not limited to the UU core. Any form of split core is applicable as long as it is composed of a pair of split cores.

The primary side circuit 12 is connected to a DC power supply 24 and is configured to be able to control the current supplied from the DC power supply 24 in a predetermined manner, specifically, configured to be able to convert direct current to alternating current at a predetermined voltage. . In this case, the transformer 11, the primary circuit 12, and the secondary circuit 13 constitute a DC-DC power converter.

In this embodiment, the primary circuit 12 is a so-called bridge circuit, and includes four switching elements 12a and an antiparallel diode 12b connected to each switching element 12a. This primary side circuit 12 is configured to be able to convert a DC voltage input from a DC power supply 24 into a high frequency square wave AC voltage. This inverter operation is performed based on a command from the controller 25 (see FIG. 1). In other words, the AC conversion conditions by the primary circuit 12, such as the magnitude of the AC voltage, can be controlled by the controller 25.

The secondary circuit 13 is configured to be able to control the current supplied from the primary circuit 12 via the transformer 11 in a predetermined manner, and specifically, is configured to be able to convert alternating current into direct current of a predetermined voltage. .

In this embodiment, the secondary circuit 13 is a so-called rectifier circuit, and includes four diodes 13a and a smoothing capacitor 13b connected in parallel to each diode 13a. The secondary circuit 13 is configured to be able to convert square wave AC voltage input from the primary circuit 12 via the transformer 11 into a DC voltage.

Capacitors 12c and 13c are connected in parallel to the primary circuit 12 and the secondary circuit 13, respectively.

The first relay 15 is disposed between the secondary circuit 13 and the secondary battery 14 and is configured to be able to switch between an energized state and a disconnected state between the secondary circuit 13 and the secondary battery 14. . That is, when the first relay 15 is on, power is supplied from the secondary circuit 13 to the secondary battery 14, and when the first relay 15 is off, power is supplied from the secondary circuit 13 to the secondary battery 14. Power will not be supplied.

The second relay 16 is arranged between the secondary circuit 13 and the first relay 15. In other words, the second relay 16 is connected in parallel with the secondary circuit 13 on the side closer to the secondary circuit 13 than the first relay 15 is. Thereby, regardless of whether the first relay 15 is on or off, it is possible to switch between an energized state and a disconnected state with the secondary circuit 13 by its own switching operation. That is, when the second relay 16 is on, the circuit including the second relay 16 connected in parallel to the secondary circuit 13 becomes energized, and when the second relay 16 is off, the second relay 16 is turned on. The included circuit is electrically cut off.

The voltage measurement unit 17 is, for example, a voltmeter, and in this embodiment is connected in series with the second relay 16. By connecting in this way, the voltage measurement unit 17 can measure the voltage of the circuit including the second relay 16 while the second relay 16 is on. In this case, since the circuit including the second relay 16 is connected in parallel with the secondary circuit 13, the voltage measured by the voltage measurement unit 17 is the voltage of the secondary circuit 13, more precisely, the voltage of the secondary circuit 13. It can be obtained as the voltage of the capacitor 13c connected in parallel with the circuit 13.

The BMU 18 serving as a control unit monitors the state (parameters such as voltage) of the secondary battery 14 and controls power supply from the secondary circuit 13 to the secondary battery 14 . In addition, the BMU 18 acquires information regarding the voltage value obtained by the voltage measurement unit 17, and determines whether the joint state of the split cores 22 and 23 is good or not based on the information regarding the voltage value, specifically, the primary coil 20 and the secondary coil 20. Processing for evaluating the positional relationship with the side coil 21 can be performed.

Furthermore, in this embodiment, the BMU 18 controls the switching operations of the first relay 15 and the second relay 16, and also transmits information acquired by the BMU 18 (for example, information regarding the voltage measurement value of the secondary battery 14) to the controller 25. It is possible.

In this case, the first divided core 22 of the transformer 11, the primary coil 20, the primary circuit 12, the DC power supply 24, and the controller 25 are provided on the charging station 26 side. In addition, the second divided core 23 of the transformer 11, the secondary coil 21, the secondary circuit 13, the secondary battery 14, the first relay 15, the second relay 16, and the voltage measurement section 17, BMU 18 is provided on the vehicle 27 side.

Next, an example of a method for supplying power to the secondary battery 14 (charging method) using the power supply system 10 having the above configuration will be described based on the flowchart shown in FIG. 2.

Here, the power supply method according to the present embodiment includes an evaluation relay switching step S1, a voltage adjustment step S3 of the primary side circuit 12, a power transmission step S4, a voltage measurement step S5 of the secondary side circuit 13, and a core coupling step S3. It includes a state evaluation step S6, a charging relay switching step S9, and a charging start step S10. It is assumed that the first divided core 22 and the second divided core 23 of the transformer 11 are butted against each other in a predetermined positional relationship. Below, each step S1 to S10 will be explained in chronological order.

(S1) Evaluation relay switching step In this step S1, each relay 15, 16 is switched in order to evaluate the core coupling state of the transformer 11. Specifically, by turning off the first relay 15 and turning on the second relay 16, the secondary circuit 13 and the secondary battery 14 are electrically disconnected, and the voltage between the secondary circuit 13 and the secondary battery 14 is cut off. The measuring section 17 is turned on. Note that the on-off operation of the first relay 15 and the second relay 16 is performed (controlled) by the BMU 18.

(S2) Voltage information transmission step (S3) Voltage adjustment step In this embodiment, first, the BMU 18 transmits information regarding the voltage of the secondary battery 14 acquired to the controller 25 of the primary circuit 12. Based on the received information regarding the voltage, the controller 25 converts the DC input from the DC power source 24 into an AC having a voltage equal to the voltage of the secondary battery 14 at a predetermined voltage. A command is sent to the side circuit 12. As a result, the primary circuit 12 generates an alternating current of the predetermined voltage.

Further, at this time, the value of the alternating current generated by the primary circuit 12 is preferably set to be smaller than the value of the alternating current generated by the primary circuit 12 when charging the secondary battery 14. As an example, the alternating current value (magnitude of the current for core coupling check) generated in the primary side circuit 12 for checking the core coupling state may be 101 to 2 orders smaller than the charging current (for example, 0.1 ~0.5A).

(S4) Power Transmission Step In this step S4, the alternating current of a predetermined voltage and a predetermined current generated in step S3 is transmitted to the secondary circuit 13 via the transformer 11. At the time when the above-mentioned alternating current is generated in the primary circuit 12, the first divided core 22 and the second divided core 23 of the transformer 11 are in a state where they are butted against each other in a predetermined positional relationship (see FIG. 1). Therefore, by generating the above-mentioned alternating current in the primary circuit 12, the electromagnetic induction effect by the first divided core 22 and the second divided core 23, and the primary coil 20 and the secondary coil 21, which are in a predetermined positional relationship, is achieved. A mutual induction effect occurs, and an alternating current (here, square wave alternating current) of a predetermined voltage and a predetermined current generated in the primary circuit 12 is supplied to the secondary circuit 13. The secondary circuit 13 converts the supplied alternating current into a predetermined direct current by its rectifying action. The converted DC power is stored in a capacitor 13c connected in parallel with the secondary circuit 13.

(S5) Voltage measurement step In this step S5, the voltage of the secondary circuit 13 is measured by the voltage measurement section 17. That is, by turning on the second relay 16 in the previous step S1, the circuit including the second relay 16 and the voltage measuring section 17 becomes electrically connected to the secondary circuit 13. Further, this circuit is connected in parallel with the secondary circuit 13. Therefore, a voltage of the same magnitude as the voltage generated in (the capacitor 13c of) the secondary circuit 13 is applied to the voltage measurement unit 17. Therefore, by measuring the voltage with this voltage measuring section 17, the voltage of the secondary side circuit 13 is measured. Note that this voltage measurement is performed over a predetermined period after power transmission from the primary circuit 12 is started.

(S6) Core connection state evaluation step When the voltage of the secondary circuit 13 during power transmission via the transformer 11 is measured as described above, based on the information regarding the measured voltage, the split core 22 constituting the transformer 11 . In the present embodiment, the positional relationship between the primary coil 20 and the secondary coil 21 is evaluated based on the temporal change in the voltage of the secondary circuit 13 obtained by the voltage measurement unit 17. At this time, in advance, the amount of voltage change in the secondary circuit 13 (for example, how much is (has the voltage increased?) and the positional relationship between the primary coil 20 and the secondary coil 21, for example, the relationship with the amount of positional deviation in the direction perpendicular to the butting direction of the split cores 22 and 23. . Further, at this time, a threshold value of the voltage change amount (for example, a lower limit value of the voltage measurement value after a predetermined period of time) is set, which corresponds to the upper limit value of the positional deviation amount within the allowable range. Then, using the data acquired in step S5, the positional relationship between the primary coil 20 and the secondary coil 21 is evaluated based on the amount of voltage change in the secondary circuit 13. In this case, for example, if the voltage measurement value after a predetermined time (e.g. 2 seconds) has elapsed from the start of measurement is equal to or higher than a preset voltage measurement value threshold (e.g. 80V), the transformer 11 is activated at a predetermined efficiency or higher. Since it can be assumed that power is being transmitted through the coils 20 and 21, the amount of positional deviation between the coils 20 and 21, as well as the amount of positional deviation between the split cores 22 and 23, is determined to be tolerably small, and the process proceeds to step S7. Note that the above determination process is performed by the BMU 18.

(S8) Secondary coil movement step Alternatively, if the voltage measurement value after a predetermined time has elapsed from the start of measurement is less than the preset voltage measurement value threshold, the transformer 11 is moved with an efficiency lower than the required efficiency. Since it can be assumed that power is being transmitted through the coils 20 and 21, it is determined that the amount of positional deviation between the coils 20 and 21, as well as the amount of positional deviation between the split cores 22 and 23, is unacceptably large, and the process proceeds to step S8. Here, step S8 will be explained first. In step S8, the secondary coil 21 is moved by the direction and magnitude that eliminates the positional deviation. In this embodiment, the secondary coil 21 is provided on the vehicle 27 side, so the above-mentioned positional deviation is eliminated by moving the vehicle 27 by a predetermined direction and amount. After that, the process returns to step S4, executes the processes of steps S4 to S6, and repeats steps S4 to S6 and S8 until the amount of positional deviation becomes tolerably small.

Although it is possible to actually detect the direction of positional deviation using a sensor or the like, for example, when the split cores 22 and 23 are connected due to movement of the vehicle 27, the direction of positional deviation may be restricted. The structure may be provided on at least one of the primary side (charging station 26 side) and the secondary side (vehicle 27 side).

(S7) Voltage evaluation step If it is determined that the amount of positional deviation between the coils 20 and 21, and also the amount of positional deviation between the split cores 22 and 23, is tolerably small, the process related to this step S7 is performed. That is, in this step S7, it is determined whether the voltage of the secondary circuit 13 has reached a level equal to the voltage of the secondary battery 14 due to the power transmitted to the secondary circuit 13 in the power transmission step S4. . This determination process is performed by the BMU 18. Note that the voltage of the secondary battery 14 here may be the voltage value related to the information transmitted to the controller 25 in step S2. If it is determined that the voltage of the secondary circuit 13 has reached the voltage of the secondary battery 14, for example, the BMU 18 transmits a command to the controller 25 to stop power transmission, and the process proceeds to step S9. This process is also executed by the BMU 18.

Alternatively, if it is determined that the voltage of the secondary circuit 13 has not reached the voltage of the secondary battery 14, power transmission from the primary circuit 12 is continued, and steps S5 to S7 are performed every predetermined time. Will try again. This series of steps S5 to S7 is repeated until the voltage of the secondary circuit 13 reaches the voltage of the secondary battery 14.

(S9) Charging relay switching step In step S9, each relay 15, 16 is switched to enable charging of the secondary battery 14 to start. Specifically, by turning on the first relay 15 and turning off the second relay 16, the secondary circuit 13 and the secondary battery 14 are electrically disconnected, and the secondary circuit 13 and the secondary battery 14 are electrically disconnected. The side circuit 13 and the voltage measuring section 17 are energized. Note that the above-described on-off switching operation of each relay 15, 16 is performed by the BMU 18.

(S10) Charging start step In this step S10, an alternating current of a predetermined voltage and a predetermined current is supplied from the primary circuit 12 to the secondary circuit 13 via the transformer 11, and a predetermined voltage rectified by the secondary circuit 13 is supplied. Direct current is supplied to the secondary battery 14. As a result, the secondary battery 14 is charged. Charging of the secondary battery 14 is controlled by the BMU 18.

As described above, in the power supply system 10 according to the present embodiment, in addition to the first relay 15 that switches the connection between the secondary circuit 13 of the transformer 11 and the secondary battery 14, the secondary circuit 13 and the Based on the change over time in the voltage of the secondary circuit 13 when the second relay 16 is connected between the relay 15 and the second relay 16 is turned on and power is supplied with the first relay 15 turned off. , the positional relationship between the primary coil 20 and the secondary coil 21 is evaluated. In this way, the positional relationship between the coils 20 and 21 and the positional relationship between the split cores 22 and 23 can be adjusted under conditions (for example, short time, low current, etc.) that are less severe than the power supply conditions during power supply (charging) to the secondary battery 14. Since it is possible to carry out power feeding for evaluating the magnetic flux, even if the relative positions of the coils 20 and 21 deviate from the normal positions, leakage of magnetic flux that occurs at that time can be reduced. As described above, according to the power supply system 10 according to the present embodiment, the secondary battery 14 can be charged with high efficiency by an external power source (here, the DC power source 24) via the transformer 11 while suppressing leakage magnetic flux. becomes possible.

In particular, in the present embodiment, the predetermined current transmitted from the primary side circuit 12 during the core bonding state evaluation step S6 is the current supplied from the primary side circuit 12 during the charging start step S10 of the secondary battery 14. (here, about ¹⁰¹ order A), it is possible to suppress the amount of leakage per hour that occurs when the relative positions between the coils 20 and 21 are deviated. Of course, even if the current is smaller than that during charging, the positional relationship between the coils 20 and 21 is determined based on the temporal change in the voltage applied to the secondary circuit 13 (in this case, the voltage measurement value after a predetermined time has elapsed). can be appropriately evaluated, so there is no problem in implementing the core connection state evaluation step S6.

Further, when charging is not performed, it is desirable that the voltage of the secondary side circuit 13 is zero or close to zero, but in the power supply system 10 according to the present embodiment, the voltage of the secondary side circuit 13 is not connected to the secondary battery 14. By turning off the first relay 15 connected in parallel with the secondary circuit 13 and turning on the second relay 16 connected in parallel with the secondary circuit 13, the charge stored in the capacitor 13c of the secondary circuit 13 can be discharged. Therefore, there is no need to provide a separate relay for discharging.

Further, as in the present embodiment, in the previous steps S4 to S7, the voltage of the capacitor 13c of the secondary side circuit 13 has increased to a magnitude equal to the measured voltage of the secondary battery 14, so that Charging can be performed under desired conditions by simply switching the relays 15 and 16 at S9. Therefore, the pre-charge relay, which conventionally needed to be connected in parallel with the main relay for charging (the first relay 15 in this embodiment) in order to protect the secondary battery 14, is no longer required, simplifying the circuit. This makes it possible to achieve

Although one embodiment of the present invention has been described above, the power feeding system and the power feeding method according to the present invention can also adopt configurations other than the above without departing from the spirit thereof.

For example, regarding the temporal change in the voltage of the secondary side circuit 13 in the core coupling state evaluation step S6, in this embodiment, the amount of voltage that has increased from the start of measurement until after a predetermined time has elapsed (for example, 100V 2 seconds after the start of measurement) ) is used as the criterion, but of course other parameters may be used as the criterion. For example, the time required from the start of measurement until reaching a predetermined voltage may be used as a criterion, or the amount of voltage rise (rate of rise) per unit time may be used as a criterion. In short, as long as data regarding the correlation with the positional relationship between the coils 20 and 21 is effectively acquired, the specific criterion for determining the change over time is arbitrary.

Furthermore, in the present embodiment, before the core coupling state evaluation step S6, the BMU 18 transmits the acquired information regarding the voltage of the secondary battery 14 to the controller 25 of the primary circuit 12 (voltage information transmission step S2), and sends a command to the primary circuit 12 to convert the direct current input from the direct current power supply 24 into an alternating current with a voltage equal to the voltage of the secondary battery 14, based on the received information regarding the voltage. However, these steps S2 and S3 may be omitted (voltage adjustment step S3). That is, as long as the coupling state of the split cores 22 and 23 (the positional relationship between the coils 20 and 21) can be properly evaluated in the core coupling state evaluation step S6, the power transmission voltage at the time of evaluating the core coupling state can be set arbitrarily. Good too.

Further, in the above embodiment, a case has been exemplified in which the voltage of the secondary side circuit 13 can be measured by the voltage measuring section 17 connected in series with the second relay 16, but of course the present invention is not limited to this. For example, the BMU 18 may measure the voltage of the secondary circuit 13. This is because the BMU 18 has a function for monitoring the voltage of the secondary battery 14 and therefore has a configuration for voltage measurement.

Further, in the above description, the case where the present invention is applied to a motor drive battery of a vehicle 27 driven by a motor such as an electric vehicle has been exemplified, but of course the present invention is not limited to this. For example, the present invention may be applied to a vehicle battery that supplies power to a power load other than a drive motor. Alternatively, the power supply system or power supply method according to the present invention may be applied not only to in-vehicle use but also to general battery applications that require continuous and stable battery drive.

10 Power supply system 11 Transformer 12 Primary circuit 13 Secondary circuit 13c Capacitor 14 Secondary battery 15 First relay 16 Second relay 17 Voltage measuring section 19 Core 20 Primary coil 21 Secondary coils 22, 23 Split core 24 DC Power supply 25 Controller 26 Charging station 27 Vehicle S1 Evaluation relay switching step S5 Voltage measurement step S6 Core connection state evaluation step S9 Charging relay switching step S10 Charging start step

Claims (4)

A transformer having a primary coil and a secondary coil;
a primary circuit that controls a current flowing through the primary coil;
a secondary circuit that controls a current flowing through the secondary coil;
a secondary battery connected to the secondary circuit;
a first relay disposed between the secondary circuit and the secondary battery;
a second relay disposed between the secondary circuit and the first relay;
a voltage measurement unit that measures the voltage of the secondary circuit;
It is equipped with a control section,
The control unit controls the voltage of the secondary circuit measured by the voltage measurement unit when the first relay is turned off, the second relay is turned on, and a predetermined current is supplied from the primary circuit. A power feeding system that evaluates a positional relationship between the primary coil and the secondary coil based on a change over time. When the control unit determines that the positional relationship between the primary coil and the secondary coil is in an allowable state, the control unit turns off the second relay, turns on the first relay, and controls the secondary coil. The power supply system according to claim 1, which starts charging the battery. The power supply system according to claim 1 or 2, wherein the predetermined current is smaller than the current supplied from the primary circuit when charging the secondary battery. The primary coil is provided at a charging station, the secondary coil is mounted on a vehicle,
When the control unit determines that the positional relationship between the primary coil and the secondary coil is not in an acceptable state, the control unit moves the secondary coil to a position where the positional relationship is in an acceptable state. The power supply system according to any one of claims 1 to 3.

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