JP6766664B2 - Power receiving device - Google Patents

Description

The present disclosure relates to a power receiving device, and more particularly to a power receiving device that receives power from a power transmitting device.

Japanese Unexamined Patent Publication No. 2016-82877 (Patent Document 1) discloses a charging device capable of communicating with a vehicle. In this charging device, when the power supply to the vehicle is interrupted and the communication with the vehicle is interrupted, a process for restarting the communication is executed. Specifically, after the power supply to the vehicle is interrupted and the communication with the vehicle is interrupted, the process for resuming the communication is repeatedly executed until the first predetermined time elapses. Then, when the communication is not restarted at the time when the first predetermined time elapses, the process for resuming the communication is executed again after the lapse of the second predetermined time longer than the first predetermined time. When the communication is resumed, the power supply to the vehicle is resumed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-82877

Consider a case where a technique related to communication resumption as disclosed in Patent Document 1 is applied to a power receiving device that receives power from a power transmitting device. In this power receiving device, when the power transmission is interrupted and the communication between the power transmitting device and the power receiving device is interrupted, the process for resuming the communication is repeatedly executed until the first predetermined time elapses. Then, when the communication is not restarted at the time when the first predetermined time elapses, the process for resuming the communication is executed again after the lapse of the second predetermined time. When communication is resumed, power transmission is resumed.

However, the time required to eliminate the cause of communication blackout varies depending on the type of cause. When it takes a long time to eliminate the cause, even if the process for resuming communication is frequently performed, the power required for the process is wasted.

The present disclosure has been made to solve such a problem, and an object thereof is a power receiving device capable of suppressing the power consumed for restarting the power transmission when the power transmission is interrupted. Is to provide.

The power receiving device according to the present disclosure includes a power receiving unit, a communication unit, and a control unit. The power receiving unit receives power from the power transmission device. The communication unit establishes communication with the power transmission device. The control unit controls the communication unit so as to transmit a signal for establishing communication to the power transmission device. When communication is interrupted or power reception is interrupted by the power receiving device, the control unit interrupts power reception when the difference between the timing of communication interruption and the timing of interruption of power reception exceeds a predetermined time. While it is determined that the cause is a communication interruption, if the difference between the communication interruption timing and the power reception interruption timing is within a predetermined time, it is determined that the cause of the power reception interruption is a power failure in the power transmission device. .. The control unit shifts to the sleep state after determining the cause of the interruption of power reception. When it is determined that the cause of the interruption of power reception is the interruption of communication, the control unit activates the communication unit at the first time interval and transmits a signal for establishing communication to the power transmission device. While controlling, if it is determined that the cause of the interruption of power reception is a power failure, it starts up at a second time interval longer than the first time interval and sends a signal to the power transmission device to establish communication. The communication unit is controlled so as to do so.

In this power receiving device, after the cause of the interruption of power receiving is identified, the control unit shifts to the sleep state, and then intermittently starts for re-receiving power. By the way, the time required for the power outage to be resolved is likely to be longer than the time required for the mere communication blackout to be resolved. In this power receiving device, the interval of intermittent activation of the control unit is set longer when the cause of the interruption is a power failure than when the cause of the interruption is simply a communication interruption. Therefore, according to this power receiving device, it is possible to suppress the control unit from being started more frequently than necessary, and thus it is possible to suppress the power consumption for restarting the power receiving.

According to the present disclosure, it is possible to provide a power receiving device capable of suppressing the power consumed for restarting the power transmission when the power transmission is interrupted.

It is a block diagram of the non-contact power transmission system. It is a figure for demonstrating the determination method of the interruption cause of non-contact power transmission. It is a figure for demonstrating the start timing of the ECU in a vehicle. It is a flowchart which shows the processing procedure after the interruption of the non-contact power transmission in a vehicle.

Hereinafter, embodiments will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

[Configuration of non-contact power transmission system]
FIG. 1 is a configuration diagram of a non-contact power transmission system 1 to which a vehicle 100 equipped with a power receiving device according to the present embodiment is applied. With reference to FIG. 1, the non-contact power transmission system 1 includes a vehicle 100 and a power transmission device 200. Non-contact power transmission is performed between the vehicle 100 and the power transmission device 200.

The power transmission device 200 includes a power transmission unit 210, a communication unit 220, and a control device 230. The power transmission device 200 receives power from an AC power source 300 (for example, a grid power source) and transmits power to the vehicle 100 through the power transmission unit 210.

The power transmission unit 210 generates power transmission based on the power supplied from the AC power source 300. For example, the power transmission unit 210 includes a rectifier and an inverter, and generates power transmission power having a desired frequency based on the power supplied from the AC power supply 300. Further, the power transmission unit 210 includes a power transmission coil (not shown). The power transmission coil forms a magnetic field by receiving the generated power transmission power, and transmits power through the formed magnetic field to the power reception coil (not shown) of the power receiving unit 110 (described later) in a non-contact manner. The number of turns of the power transmission coil is appropriately designed so that the Q value (for example, Q ≧ 100) and the coupling coefficient κ are large.

The communication unit 220 can communicate with the communication unit 130 (described later) of the vehicle 100. The communication unit 220 is composed of, for example, a wireless LAN (Local Area Network) module conforming to IEEE (Institute of Electrical and Electronics Engineers) 802.11. The communication unit 220 functions as a master unit in the wireless LAN. Communication between the communication units 220, 130 is established, for example, to initiate non-contact power transmission. In the communication between the communication units 220 and 130, for example, information regarding the start / stop of power transmission and information regarding the power reception status (power reception voltage, power reception current, power reception power, etc.) of the power reception unit 110 are exchanged.

The control device 230 has a built-in CPU (Central Processing Unit) and a memory (not shown), and each device (power transmission unit 210, transmission unit 210) of the power transmission device 200 is based on the information stored in the memory and the information from each sensor (not shown). Communication unit 220, etc.) is controlled. The control device 230 controls the power transmission unit 210 so as to stop the power transmission after a certain period of time, for example, when the communication between the communication units 220 and 130 is interrupted due to a cause other than a power failure in the power transmission device 200 during non-contact power transmission. To do.

The vehicle 100 includes a power receiving unit 110, a power storage device 120, a communication unit 130, and an ECU (Electronic Control Unit) 140. In the vehicle 100, the electric power received from the power transmission device 200 in a non-contact manner is stored in the power storage device 120. Then, in the vehicle 100, a traveling driving force is generated based on the electric power stored in the power storage device 120.

The power receiving unit 110 includes a power receiving coil (not shown). The power receiving coil receives power from the power transmission coil (not shown) of the power transmission unit 210 in a non-contact manner. The electric power (alternating current) received by the power receiving coil is converted into DC electric power, the voltage is converted into a desired voltage, and then stored in the power storage device 120 (described later). The number of turns of the conducting wire in the power receiving coil is appropriately designed so that the Q value (for example, Q ≧ 100) and the coupling coefficient κ are large.

The power storage device 120 is a rechargeable DC power source, and is composed of a secondary battery such as a lithium ion battery or a nickel hydrogen battery. The power storage device 15 may be a large-capacity capacitor. The power storage device 120 stores the electric power output from the power receiving unit 110.

The communication unit 130 can communicate with the communication unit 220 of the power transmission device 200. The communication unit 130 is composed of, for example, a wireless LAN module conforming to IEEE802.11. The communication unit 130 functions as a slave unit in the wireless LAN. The communication unit 130 is configured to transmit a signal for establishing communication with the communication unit 220 (hereinafter, also referred to as a “communication establishment signal”) to the communication unit 220. Communication between the communication units 130 and 220 is established due to the transmission of the communication establishment signal from the communication unit 130.

The ECU 140 has a built-in CPU and memory (not shown), and controls each device (power receiving unit 110, communication unit 130, etc.) of the vehicle 100 based on the information stored in the memory and the information from each sensor (not shown). ..

[Method of determining the cause of interruption of non-contact power transmission]
The non-contact power transmission from the power transmission device 200 to the vehicle 100 may be interrupted due to various causes. For example, when the wireless communication between the communication units 130 and 220 is interrupted, the non-contact power transmission is interrupted. Further, when a power failure occurs in the power transmission device 200 (for example, when the power supply from the AC power source 300 to the power transmission device 200 is interrupted for some reason), the non-contact power transmission is also interrupted. The ECU 140 has a function of determining the cause of the interruption of power reception (interruption of non-contact power transmission) by the power receiving unit 110 when the power receiving is interrupted by the power receiving unit 110.

FIG. 2 is a diagram for explaining a method of determining a cause of interruption of non-contact power transmission. With reference to FIG. 2, the horizontal axis represents time. From the top, the vertical axis shows a change in the wireless communication state when a power failure occurs in the power transmission device 200 or when a communication interruption occurs between the communication units 130 and 220, and when a communication interruption occurs between the communication units 130 and 220. The change of the received power by the power receiving unit 110 and the change of the received power by the power receiving unit 110 when a power failure occurs in the power transmission device 200 are shown.

It is assumed that communication interruption due to a power failure in the power transmission device 200 or communication interruption due to a cause other than the power failure occurs at time t1. When a communication blackout occurs due to a cause other than a power failure (hereinafter, also referred to as "mere communication blackout"), the power received by the power receiving unit 110 exceeds a predetermined time (for example, a predetermined time = t2-t1) from the communication blackout. Suspended after some time has passed. On the other hand, when a communication interruption occurs due to a power failure, the power reception by the power receiving unit 110 is interrupted immediately after the communication interruption (after a predetermined time (for example, a predetermined time = t2-t1) or less has elapsed from the communication interruption). To. The predetermined time is, for example, a time shorter than the time from the occurrence of a mere communication blackout until the power transmission device 200 stops power transmission, and a time sufficiently longer than the time until the power reception is stopped when a power failure occurs. Is.

The ECU 140 can detect the timing of a communication blackout by monitoring the communication status between the communication units 130 and 220, for example. Further, the ECU 140 can detect the timing at which the power reception is interrupted by monitoring the output of the voltage sensor (not shown) that detects the power reception voltage of the power reception unit 110, for example. Information indicating the detected communication interruption timing and information indicating the detected power reception interruption timing are stored in, for example, the internal memory of the ECU 140.

When the difference between the timing at which the communication interruption occurs and the timing at which the power reception interruption occurs exceeds a predetermined time, the ECU 140 determines that the cause of the power reception interruption is a mere communication interruption, while the communication interruption occurs. When the difference between the timing of occurrence and the timing of interruption of power reception is within a predetermined time, it is determined that the cause of the interruption of power reception is a power failure in the power transmission device 200.

[Processing after interruption of non-contact power transmission]
When the non-contact power transmission from the power transmission device 200 to the vehicle 100 is interrupted, it is necessary to reestablish the communication between the communication units 130 and 220 in order to restart the non-contact power transmission. The timing at which communication between the communication units 130 and 220 can be established differs depending on the cause of the communication blackout. For example, the time required to eliminate the power failure in the power transmission device 200 is likely to be longer than the time required to eliminate the cause of the communication blackout other than the power failure. That is, when the communication is interrupted due to the power failure, the time required for resuming the communication is longer than when the communication is interrupted due to a cause other than the power failure. For example, if the process for resuming communication (for example, the process of transmitting a communication establishment signal from the communication unit 130 to the communication unit 220) is frequently performed even though the time required for resuming communication is long, the process is required. Power is wasted.

Therefore, in the vehicle 100 according to the present embodiment, the ECU 140 determines the cause of the interruption of the power transmission, and then shifts to the sleep state. The sleep state is a state in which power consumption is low and the use of some functions is restricted. Then, when it is determined that the cause of the interruption of the power transmission is simply a communication interruption, the ECU 140 controls the communication unit 130 so as to start at the time interval T1 and transmit the communication establishment signal to the power transmission device 200. On the other hand, when it is determined that the cause of the interruption of the power transmission is a power failure in the power transmission device 200, the communication is started so as to start at a time interval T2 longer than the time interval T1 and transmit the communication establishment signal to the power transmission device 200. The unit 130 is controlled. According to the vehicle 100, when it is unlikely that the cause of the communication interruption has been resolved, the ECU 140 is suppressed from being started more frequently than necessary, so that the power consumption for resuming power reception can be suppressed. it can.

FIG. 3 is a diagram for explaining the activation timing of the ECU 140 in the vehicle 100. With reference to FIG. 3, each horizontal axis represents time, and the vertical axis represents the activation timing of the ECU 140 and the power transmission when the non-contact power transmission is interrupted due to the communication interruption between the communication units 130 and 220 from above. The start timing of the ECU 140 when the non-contact power transmission is interrupted due to the power failure in the device 200 is shown.

When the non-contact power transmission is interrupted due to a mere communication blackout, the ECU 140 is intermittently started at the time interval T1 until time t01 (for example, until it is started four times). On the other hand, when the non-contact power transmission is interrupted due to a power failure, the ECU 140 is intermittently started at the time interval T2 (time interval T2> time interval T1) until time t02 (for example, until it is started four times).

After the time t01 when the non-contact power transmission is interrupted due to a mere communication interruption, and after the time t02 when the non-contact power transmission is interrupted due to a power failure, the ECU 140 performs the time interval T3 (time interval T3> time interval T2). ) To start intermittently.

In the vehicle 100 according to the present embodiment, even if the ECU 140 is activated a predetermined number of times (for example, four times) and a communication establishment signal is transmitted to the communication unit 220 each time, communication between the communication units 130 and 220 is resumed. If not, the activation interval of the ECU 140 is further extended. Therefore, according to the vehicle 100, when it is extremely unlikely that the cause of the communication interruption has been eliminated, the ECU 140 does not start more than necessary, so that the power consumption for restarting the non-contact power transmission can be further suppressed. it can.

[Processing procedure after interruption of non-contact power transmission]
FIG. 4 is a flowchart showing a processing procedure after interruption of non-contact power transmission in the vehicle 100. The process shown in this flowchart is executed by the ECU 140 when the non-contact power transmission is interrupted and the communication between the communication units 130 and 220 is interrupted.

With reference to FIG. 4, the ECU 140 determines the cause of the interruption of the non-contact power transmission (step S100). Specifically, the ECU 140 determines whether a power failure has occurred in the power transmission device 200 or whether communication between the communication units 130 and 220 has been interrupted due to a cause other than the power failure by the above method.

When it is determined that the communication interruption has occurred due to a cause other than the power failure (“communication interruption” in step S100), the ECU 140 sets the time interval for intermittent activation to T1 and then shifts to the sleep state (step S110). On the other hand, when it is determined that a power failure has occurred (“power failure” in step S100), the ECU 140 sets the time interval for intermittent activation to T2, and then shifts to the sleep state (step S120). The ECU 140 is activated at a set time interval (T1 or T2), and controls the communication unit 130 so as to transmit a communication establishment signal to the power transmission device 200.

After that, the ECU 140 determines whether or not communication between the communication units 130 and 220 has been established even if the ECU 140 is activated a predetermined number of times (step S130). If communication is established within a predetermined number of times (NO in step S130), the ECU 140 controls the communication unit 130 to transmit a power transmission start instruction to the power transmission device 200 (step S155). After that, the process shifts to the end.

On the other hand, if it is determined that the communication has not been established within the predetermined number of times (YES in step S130), the ECU 140 resets the intermittent start time interval to T3, and then shifts to the sleep state (step S140). The ECU 140 is activated at the set time interval (T3), and controls the communication unit 130 so as to transmit the communication establishment signal to the power transmission device 200.

Then, the ECU 140 determines whether or not communication between the communication units 130 and 220 has been established even if the ECU 140 is started again a predetermined number of times (step S150). When communication is established within a predetermined number of times (NO in step S150), the ECU 140 controls the communication unit 130 so as to transmit a communication start instruction to the power transmission device 200 (step S155). After that, the process shifts to the end. On the other hand, if communication is not established within a predetermined number of times (YES in step S150), the process shifts to the end after the ECU 140 is activated a predetermined number of times.

As described above, in the vehicle 100 according to the present embodiment, when it is determined that the cause of the interruption of the power transmission is a mere communication interruption, the ECU 140 is activated at the time interval T1 to transmit the communication establishment signal to the power transmission device. While controlling the communication unit 130 so as to transmit to 200, when it is determined that the cause of the interruption of power transmission is a power failure in the power transmission device 200, the communication unit 130 is activated at a time interval T2 longer than the time interval T1 for communication. The communication unit 130 is controlled so as to transmit the establishment signal to the power transmission device 200. According to the vehicle 100, since it is suppressed that the ECU 140 is started more frequently than necessary, it is possible to suppress the power consumption for restarting the power reception.

In the present embodiment, the ECU 140 is started a predetermined number of times at a set time interval, but it is not always necessary to start the ECU 140 a predetermined number of times. For example, when the ECU 140 monitors the remaining amount of the auxiliary battery (not shown) and the remaining amount of the auxiliary battery falls below a predetermined amount, the ECU 140 is started intermittently even if the number of times of starting the ECU 140 does not reach the predetermined number. May be configured to stop. As a result, it is possible to avoid a situation in which the remaining amount of the auxiliary battery is lower than expected.

Further, in the present embodiment, an example in which the present technology is applied to a non-contact power transmission system has been described. However, the present technology is applied to, for example, a contact charging system in which power is transmitted from a power transmission device to a vehicle via a charging cable. Can also be applied. Also in this case, the cause of the power transmission interruption (power failure or communication interruption) is determined in the vehicle, and the timing of intermittent activation of the ECU of the vehicle is changed according to the cause of the power transmission interruption.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Non-contact power transmission system, 100 vehicles, 110 power receiving unit, 120 power storage device, 130, 220 communication unit, 140 ECU, 200 power transmission device, 210 power transmission unit, 230 control device, 300 AC power supply.

Claims (1)

The power receiving unit that receives power from the power transmission device and
A communication unit that establishes communication with the power transmission device,
A control unit that controls the communication unit so as to transmit a signal for establishing the communication to the power transmission device is provided.
When the communication is interrupted and the power reception is interrupted by the power receiving unit, the control unit may interrupt the communication.
When the difference between the timing of the interruption and the timing of the interruption exceeds a predetermined time, it is determined that the cause of the interruption is the interruption.
When the difference between the timing of the interruption and the timing of the interruption is within a predetermined time, it is determined that the cause of the interruption is a power failure in the power transmission device.
The control unit
After the cause is determined, the sleep state is entered.
When it is determined that the cause is the interruption, the communication unit is controlled so as to start at the first time interval and transmit the signal to the power transmission device.
When it is determined that the cause is the power failure, the communication unit is controlled so as to start at a second time interval longer than the first time interval and transmit the signal to the power transmission device. , Power receiving device.

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