JP7569205B2 - Power Transmission System - Google Patents

Description

The present invention relates to a power transmission system that transmits power contactlessly to a power receiving device installed in a mobile object.

Until now, technologies related to contactless charging have been proposed for battery-equipped mobile bodies such as electric vehicles, in which the battery is charged without contact with a power source while the mobile body is moving. In particular, when applying contactless charging using electromagnetic induction or magnetic field resonance, technologies have been proposed in which the mobile body is equipped with a power receiving device including a receiving coil and the like, and a power transmitting device including a transmitting coil and the like is arranged on the path of travel of the mobile body. For example, in vehicles equipped with batteries such as electric vehicles and hybrid cars, the vehicle is equipped with a power receiving device that connects to the battery, and a power transmitting device is arranged on the road along which the vehicle travels.

When adopting such a configuration, from the standpoint of cost and facility layout, it is not realistic to connect a power source to each power transmission device and have all the power transmission devices always running and transmitting power. For this reason, multiple power transmission devices are connected to a single power distribution system to which power is supplied from a power source, and each power transmission device is started and stopped as needed. Thus, there is a demand for technology to appropriately control the starting and stopping of each power transmission device.

Patent document 1 discloses a device for contactlessly charging an electric vehicle. This device detects changes in the electrical characteristics of the charging circuit (power transmission device) and determines whether to operate or stop the charging circuit (power transmission device) based on the amount of change in the electrical characteristics of the charging circuit (power transmission device).

Special table 2017-532930 publication

Ideally, the power transmission device closest to the moving object should be driven and the other power transmission devices should be stopped. However, in the situations typically assumed by this technology, the time it takes for the moving object to pass each power transmission device is short. For this reason, it is necessary to detect the passing position of the moving object with high accuracy and appropriately control the driving and stopping of each power transmission device. In addition, obtaining information by communicating with the moving object and identifying the passing position of the moving object is not desirable because of the communication time required.

Patent Document 1 discloses a method for determining whether to start or stop a power transmission device based on the amount of change in the electrical characteristics of the power transmission device. However, the electrical characteristics differ depending on the position of the power receiving device provided on the moving object, the positional deviation between the power receiving device and the power transmission device due to deviation from the center of the moving path, etc. Such positional deviations can occur frequently. For example, when the moving object is a vehicle, the vehicle may have a different height or may run on the inside of a road. For this reason, simply evaluating the amount of change in the electrical characteristics may not provide sufficient accuracy for the moving object's passing position, and there is a risk that the power transmission device may not be started or stopped appropriately. This may ultimately cause problems such as power pulsation and increased leakage magnetic fields.

The present invention was made in consideration of the above-mentioned problems, and aims to propose a power transmission system that can appropriately start and stop the power transmission device with respect to the position where the moving object passes, even if a positional deviation occurs.

The power transmission system according to the present invention is a power transmission system that transmits power contactlessly to a power receiving device provided in a mobile object, and includes multiple power transmission devices, multiple inverters, a power transmission control device, and multiple sensors. The power transmission devices are arranged in a series on the path of travel of the mobile object. The inverter converts power from a power source and supplies the power to the power transmission devices via a power distribution system. The power transmission control device controls the driving and stopping of each power transmission device. The sensor detects the current flowing in the power distribution system related to each inverter.

Each power transmission device is connected to a power distribution system other than the power distribution system to which the power transmission devices located before and after it are connected. The power transmission control device detects the peak current value, which is the maximum value of the current flowing through the power distribution system. Then, it controls the operation and stopping of each power transmission device based on a standard value obtained by dividing the current value flowing through the power distribution system by the peak current value.

The inventors of this application have found that changes in the standard values are hardly affected by positional deviations. According to the present invention, the driving and stopping of each power transmission device is controlled based on the standard values. This makes it possible to drive and stop each power transmission device appropriately with respect to the position where the moving object passes, even if a positional deviation occurs.

1 is a conceptual diagram illustrating a configuration example of a power transmission system according to an embodiment. 1 is a graph showing a current flowing in a power distribution system when a vehicle passes by a power transmission device in motion. In this graph, the current values are normalized by the peak current values for each of the graphs shown in FIG. In this graph, the current values in the graphs shown in FIG. 2 are normalized by the peak current value and the minimum value of the output current of the inverter. 4 is a flowchart showing a process executed by a power transmission control device according to the first embodiment. 4 is a flowchart showing a process executed by a power transmission control device according to the first embodiment. 3 is a conceptual diagram for explaining driving and stopping of a power transmission device by a power transmission control device according to a first embodiment. FIG. FIG. 13 is a conceptual diagram illustrating a configuration example of a power transmission system according to a modified example. 10 is a graph showing a current flowing through a power distribution system when a vehicle passes through a power transmission device being driven in a modified example. 10 is a conceptual diagram for explaining driving and stopping of a power transmission device by a power transmission control device according to a modified example of the first embodiment. FIG. 10 is a flowchart showing a process executed by a power transmission control device according to a second embodiment; 10 is a flowchart showing a process executed by a power transmission control device according to a second embodiment; 13 is a conceptual diagram for explaining driving and stopping of a power transmission device by a power transmission control device according to a second embodiment. FIG.

The following describes the embodiments of the present invention with reference to the drawings. However, when the numbers, quantities, amounts, ranges, etc. of each element are mentioned in the embodiments shown below, the invention is not limited to the mentioned numbers unless otherwise specified or the numbers are clearly specified in principle. Furthermore, the structures described in the embodiments shown below are not necessarily essential to the invention unless otherwise specified or the numbers are clearly specified in principle. In addition, the same reference numerals are used for the same or corresponding parts in each drawing, and duplicate explanations are appropriately simplified or omitted.

1. First embodiment 1-1. Configuration Fig. 1 is a conceptual diagram showing a configuration example of a power transmission system 10 according to the present embodiment. The power transmission system 10 includes a plurality of power transmission devices 100, a plurality of inverters 110, a power transmission control device 120, and a plurality of sensors 130. Fig. 1 shows a case where a vehicle (mobile body) 20 including a power receiving device 200 and a battery 210 travels on a road RD. In other words, the road RD is a travel route (movement route) of the vehicle 20. The vehicle 20 is, for example, an electric vehicle or a hybrid vehicle.

The power transmission devices 100 are arranged in a row on the road RD. In the configuration example shown in FIG. 1, five power transmission devices 100 are illustrated, but more power transmission devices 100 may be arranged over a longer distance on the road RD. The power receiving device 200 is installed on the underside of the vehicle 20. In FIG. 1, the five power transmission devices 100 are denoted with symbols (n1, n2, n3, n4, n5) to distinguish between them. Similarly, the two inverters 110 are denoted with symbols (a, b) to distinguish between them.

The power transmitting device 100 and the power receiving device 200 transmit power from the power transmitting device 100 to the power receiving device 200 by magnetically resonating with each other between the coils included in each device. In other words, non-contact charging is performed using a magnetic field resonance method. However, non-contact charging using an electromagnetic induction method may also be used.

The power transmitting device 100 typically includes a series resonant circuit configured with a power transmitting coil and a resonant capacitor. It may further include a filter for suppressing high-frequency current. The power receiving device 200 typically includes a series resonant circuit configured with a power receiving coil and a resonant capacitor, and a rectifier circuit that converts the received AC power into smoothed DC power. It may further include a filter for suppressing high-frequency current. The power receiving device 200 is connected to a battery 210, and the battery 210 is charged by the DC power output from the rectifier circuit.

Battery 210 is a rechargeable DC power source that includes a secondary battery such as a lithium ion battery or a nickel-metal hydride battery.

The inverter 110 is connected to the power source 30 and converts the power of the power source 30. The converted power is then supplied to each power transmission device 100 via the power distribution system 111. Note that in FIG. 1, each inverter 110 is connected to the same power source 30, but each inverter 110 may be configured to connect to a separate power source 30. Also, in FIG. 1, the symbols (a, b) are added to the reference numerals of the power distribution systems 111 associated with each inverter 110 so as to correspond to each inverter 110.

Each power transmission device 100 is connected to a power distribution system 111 different from the power distribution system 111 to which the power transmission devices 100 located before and after it are connected. For example, in the configuration example shown in FIG. 1, power transmission device 100n2 is connected to power distribution system 111a, and power transmission devices 100n1 and 100n3 located before and after it are connected to power distribution system 111b. Similarly, power transmission devices 100n1, 100n3, 100n4, and 100n5 are connected to a power distribution system 111 different from the power distribution system 111 to which the power transmission devices located before and after them are connected.

In the configuration example shown in FIG. 1, two inverters 110 are illustrated, but more inverters 110 and power distribution systems 111 may be provided. However, even when more power distribution systems 111 are provided, as described above, each power transmission device 100 is connected to a power distribution system 111 other than the power distribution system 111 to which the power transmission device 100 located before and after it is connected.

The power supply 30 is typically an AC power supply. For example, it is a three-phase 200V or 400V, 50Hz system power supply that receives power from a power grid.

The inverter 110 includes a converter circuit that converts the AC power of the power source 30 into DC power, and an inverter circuit that converts the DC power output from the ACDC converter circuit into AC power of a predetermined frequency. Alternatively, the inverter 110 may be configured with separate devices corresponding to the converter circuit and the inverter circuit. The converter circuit and the inverter circuit typically include switching elements, and are operated by switching control performed by a control device (not shown). The frequency of the AC power output by the inverter 110 is high, for example, about 85 kHz.

The sensor 130 detects the current flowing in the power distribution system 111 associated with each inverter 110. In particular, the sensor 130 may detect the output current of each inverter 110. In this case, the sensor 130 may be configured integrally with each inverter 110. In FIG. 1, the symbols (a, b) are added to the reference numerals of the sensors 130 to correspond to each inverter 110.

The power transmission control device 120 acquires detection values from the sensor 130, and generates and outputs control signals for the drive units 101 corresponding to each power transmission device 100. The drive units 101 operate according to the control signals and are configured to be able to switch between driving and stopping the corresponding power transmission device 100. In other words, the power transmission control device 120 controls the driving and stopping of each power transmission device 100.

The drive unit 101 is composed of, for example, a relay or a switch, and switches between driving and stopping the power transmission device 100 by opening and closing the circuit. FIG. 1 shows an example in which the drive unit 101 is composed of a switch, with the drive unit 101n2 being ON and the other drive units 101 being OFF. Therefore, the power transmission device 100n2 is driven and the other power transmission devices 100 are stopped.

The power transmission control device 120 is typically a computer including a memory and a processor. The memory includes a RAM (Random Access Memory) that temporarily stores data, and a ROM (Read Only Memory) that stores a control program executable by the processor and various data related to the control program. The processor reads the program from the memory and executes processing according to the program based on the various data read from the memory. In particular, in the power transmission control device 120, a program related to control of driving and stopping the power transmission device 100 and detection values obtained from the sensor 130 are stored in the memory. Then, the processor executes processing according to the program related to control of driving and stopping the power transmission device 100 based on the data read from the memory. Details of the processing executed by the processor of the power transmission control device 120 will be described later.

1-2. Characteristics of the current flowing in the power distribution system Hereinafter, the characteristics of the current flowing in the power distribution system 111 will be described based on the configuration described above.

As shown in FIG. 1, assume that only the power transmission device 100n2 connected to the power distribution system 111a is operating. In this case, when the vehicle 20 passes the power transmission device 100n2, the input impedance varies depending on the position where the vehicle 20 passes, and the current flowing through the power distribution system 111 changes. Furthermore, the change in the current flowing through the power distribution system 111 differs depending on the gap between the power transmission device 100 (power transmission coil) and the power receiving device 200 (power receiving coil) and the misalignment of the power transmission device 100 (power transmission coil) and the power receiving device 200 (power receiving coil) in the vehicle width direction. These can occur due to differences in the vehicle height of the passing vehicle 20 or when the vehicle 20 is traveling off the center of the road RD.

2 is a graph showing the change in the current flowing through the power distribution system 111 when the vehicle 20 passes through the power transmission device 100 being driven. In the graph shown in FIG. 2, the horizontal axis shows the passing position of the vehicle, and the vertical axis shows the value of the current flowing through the power distribution system 111. Three graphs are shown in FIG. 2. The graph shown as the reference (solid line) is a graph in the case where a vehicle 20 with a certain vehicle height (gap) runs in the center of the road RD (no deviation in the vehicle width direction) and passes the power transmission device 100. The graph shown as the small gap (dashed line) is a graph in the case where a vehicle 20 with a lower vehicle height (smaller gap) than the reference runs in the center of the road RD and passes the power transmission device 100. The graph shown as the large deviation in the vehicle width direction (dash line) is a graph in the case where a vehicle 20 with a vehicle height (gap) similar to the reference runs significantly off the center of the road RD. The closest position is the position at which the vehicle 20 passes and at which the power transmission device 100 (power transmission coil) and the power receiving device 200 (power receiving coil) are closest to each other.

As shown in FIG. 2, in both cases, the current value increases as the vehicle approaches the closest position, reaches a maximum value (peak current value) at the closest position, and then decreases as the vehicle moves away from the closest position. However, the degree of current change differs depending on the gap and the difference in the vehicle width direction. For example, as shown in FIG. 2, when the gap is small, the current change is large. On the other hand, when the difference in the vehicle width direction is large, the current change is small. For this reason, there is a risk that sufficient accuracy will not be obtained when determining the passing position of the vehicle 20 from the value of the current flowing in the power distribution system 111.

Figure 3 shows a graph in which the current values in each graph shown in Figure 2 have been normalized by dividing them by the peak current value. The structure of the graph shown in Figure 3 is the same as that of the graph shown in Figure 2, except that the vertical axis shows the normalized value obtained by dividing the current value by the peak current value. The normalized value is expressed by the following formula (1).

As shown in FIG. 3, the degree of change in the standard value is little affected by differences in the gap or deviations in the vehicle width direction. Therefore, accuracy is improved by determining the passing position of the vehicle 20 based on the standard value.

Normalization can also be performed using the peak current value and the minimum value (minimum current value) of the output current of the inverter 110. In this case, the normalized value is expressed by the following formula (2).

Figure 4 shows a graph of normalization by the peak current value and the minimum value (minimum current value) of the output current of the inverter 110. The configuration of the graph shown in Figure 4 is equivalent to the configuration of the graph shown in Figure 3. As shown in Figure 4, even when normalization is performed by the peak current value and the minimum value (minimum current value) of the output current of the inverter 110, the degree of change in the normalized value is less affected by differences in the gap or misalignment in the vehicle width direction.

1-3. Processing Executed by the Power Transmission Control Device The following describes processing executed by the power transmission control device 120 according to the first embodiment. Note that, in practice, this processing is executed by the processor of the power transmission control device 120.

The power transmission control device 120 controls the driving and stopping of each power transmission device 100 based on the standard value. Figures 5 and 6 are flowcharts showing the processing executed by the power transmission control device 120 according to the first embodiment. Note that A and B shown in Figures 5 and 6 correspond to each other between Figures 5 and 6, and Figures 5 and 6 show one flowchart.

The process shown in FIG. 5 and FIG. 6 is started when the condition for driving the first power transmission device 100n1 is satisfied. Here, the first power transmission device 100n1 is the first power transmission device 100 to be driven among the multiple power transmission devices 100 arranged in a row on the road RD. For example, this is the power transmission device 100 that the vehicle 20 passes first in the traveling direction when the vehicle 20 travels on the road RD on which the power transmission devices 100 are arranged. The condition for driving the power transmission device 100n1 is, for example, when it is detected that the vehicle 20 has passed a point just before the power transmission device 100n1 and there is no branch before passing the power transmission device 100n1.

In step S100, the power transmission control device 120 drives the power transmission device 100n1. In addition, i, which is a value indicating the power transmission device 100 to be controlled, is set to 1. After step S100, the process proceeds to step S110.

In step S110, the power transmission control device 120 acquires the current value of the power distribution system 111 to which the power transmission device 100ni is connected. Immediately after the start of the process, i=1, so the acquired current value is the current value of the power distribution system 111a to which the power transmission device 100n1 is connected. After step S110, the process proceeds to step S120.

In step S120, the power transmission control device 120 determines whether the peak current value storage flag is 1. The peak current value storage flag is a Boolean value that is 1 if the peak current value has been stored and is 0 if it has not been stored. That is, in step S120, the power transmission control device 120 determines whether the peak current value has been stored. If the peak current value has been stored (step S120; Yes), the process proceeds to step S130. If the peak current value has not been stored (step S120; No), the process proceeds to step S121.

In step S121, the power transmission control device 120 determines whether the current value acquired in step S110 has passed the peak current value. The fact that the peak current value has been passed can be determined, for example, by detecting that the rate of change of the current value has become negative. If it is determined that the peak current value has been passed (step S121; Yes), the process proceeds to step S122. If it is determined that the peak current value has not been passed (step S121; No), the process returns to step S110 and is repeated.

In step S122, the power transmission control device 120 stores the peak current value. It also sets the peak current value storage flag to 1. The peak current value is given, for example, as the maximum current value acquired during a predetermined time period in the past. After step S122, the process returns to step S110 and the process is repeated.

In step S130, the power transmission control device 120 calculates the standard value. The standard value is calculated from the current value acquired in step S110 and the peak current value stored in step S122 using formula (1). Alternatively, the standard value is calculated using formula (2) further using the minimum current value. After step S130, the process proceeds to step S140.

In step S140, the power transmission control device 120 determines whether the drive flag is 1. The drive flag is a Boolean value that is set to 1 if the immediately preceding power transmission device 100n(i+1) is being driven in step S142 described below, and is set to 0 if it is not being driven. That is, in step S140, the power transmission control device 120 determines whether the power transmission device 100n(i+1) is being driven. If the power transmission device 100n(i+1) is being driven (step S140; Yes), the process proceeds to step S150. If the power transmission device 100n(i+1) is not being driven (step S140; No), the process proceeds to step S141.

In step S141, the power transmission control device 120 determines whether the standard value calculated in step S130 is less than a predetermined threshold value k1. The threshold value k1 is a threshold value that is a condition for driving the power transmission device 100n(i+1) and is a value that is given to the program in advance. This is given experimentally, for example, so as to maximize charging efficiency. If the standard value is less than the threshold value k1 (step S141; Yes), the process proceeds to step S142. If the standard value is equal to or greater than the threshold value k1 (step S141; No), the process returns to step S110 and the process is repeated.

In step S142, the power transmission control device 120 drives the power transmission device 100n(i+1). It also sets the drive flag to 1. However, if the power transmission device 100ni is the last of the series of power transmission devices 100 and the power transmission device 100n(i+1) does not exist, the power transmission device will not be driven. After step S142, the process returns to step S110 and the process is repeated.

In step S150, the power transmission control device 120 determines whether the standard value calculated in step S130 is less than a predetermined threshold value k2. The threshold value k2 is a threshold value that is a condition for stopping the power transmission device 100ni, and is a value that is given to the program in advance. Note that the threshold value k2 is given to be a value smaller than the threshold value k1. If the standard value is less than the threshold value k2 (step S150; Yes), the process proceeds to step S160. If the standard value is equal to or greater than the threshold value k2 (step S150; No), the process returns to step S110 and the process is repeated.

In step S160, the power transmission control device 120 stops the power transmission device 100ni. In addition, the peak current value storage flag and the drive flag are set to 0. After step S160, the process proceeds to step S170.

In step S170, the power transmission control device 120 determines whether the power transmission device 100ni is the terminal device. This can be done, for example, by acquiring the number N of power transmission devices 100 to be placed or by providing this number in advance to the program, and determining whether i is N. If the power transmission device 100ni is the terminal device (step S170; Yes), the process ends. If the power transmission device 100ni is not the terminal device (step S170; No), the process proceeds to step S180.

In step S180, the power transmission control device 120 increments i. After step S180, the process returns to step S110 and repeats the process.

By the above-described process, the power transmission control device 120 according to the first embodiment can appropriately drive and stop each power transmission device 100 with respect to the passing position of the vehicle 20. FIG. 7 is a conceptual diagram for explaining the driving and stopping of the power transmission device 100 by the power transmission control device 120 according to the first embodiment. FIG. 7 shows a case where the vehicle 20 passes the power transmission device 100n2 that is in operation. In the order in which the vehicle 20 passes the power transmission device 100n2, (a), (b), and (c) are shown graphs of current values or standard values, and conceptual diagrams showing the passing position of the vehicle 20 and the state (driven or stopped) of the power transmission device 100. The vertical axis of the graph (a) is the current value, and the vertical axis of the graphs (b) and (c) is the standard value.

In (a), the power transmission control device 120 acquires the current value of the power distribution system 111a connected to the power transmission device 100n2 (step S110 (i=2)). Then, the power transmission control device 120 determines that the current value has passed the peak current value (step S121) and stores the peak current value (step S122).

In (b), the power transmission control device acquires the current value of the power distribution system 111a connected to the power transmission device 100n2 (step S110 (i=2)) and calculates the standard value (step S130). Then, the power transmission control device 120 determines that the standard value is less than the threshold value k1 (step S141) and drives the power transmission device 100n3 (step S142). Note that even if the two power transmission devices 100n2 and 100n3 are driven, the characteristics of the acquired current value do not change due to the driving of the power transmission device 100n3, because the power transmission devices are connected to different power distribution systems 111.

In (c), the power transmission control device 120 acquires the current value of the power distribution system 111a connected to the power transmission device 100n2 (step S110 (i=2)) and calculates the standard value (step S130). Then, the power transmission control device 120 determines that the standard value is less than the threshold value k2 (step S150) and stops the power transmission device 100n2 (step S160). After that, the same processes as (a), (b), and (c) are repeated for the power transmission device 100n3.

1-4. Modification The power transmission system 10 according to the first embodiment may be applied to a mobile body including a plurality of power receiving devices 200. Fig. 8 is a conceptual diagram for illustrating a configuration example of the power transmission system 10 according to the modification. As shown in Fig. 8, a vehicle 20 (mobile body) includes a plurality of power receiving devices 200. The configuration of the power transmission system 10 may be the same as that shown in Fig. 1.

When the vehicle 20 is equipped with multiple power receiving devices 200, the change in current flowing through the power distribution system 111 differs from that shown by the graph in FIG. 2. This is because the positional relationship between each power receiving device 200 and the power transmission device 100 is different. FIG. 9 shows a graph showing the change in current flowing through the power distribution system 111 when the vehicle 20 is equipped with multiple power receiving devices 200, and a graph normalized by dividing the current value by the peak current value. The configuration of the graph in FIG. 9 is the same as that shown in FIG. 2 and FIG. 3.

As shown in FIG. 9, the change in current flowing through the power distribution system 111 is different from when the vehicle 20 is equipped with one power receiving device 200 (as shown by the graph in FIG. 2). However, the peak current value occurs at the closest position, and normalization by the peak current value reduces the effects of gap differences and misalignment in the vehicle width direction. Therefore, by the power transmission control device 120 suitably executing the processes shown in FIG. 5 and FIG. 6, it is possible to drive and stop each power transmission device 100 appropriately for the position where the vehicle 20 passes. Note that normalization may be calculated using the peak current value and the minimum current value according to formula (2).

In this case, attention should be paid to the processing of step S121. This is because, if the vehicle 20 is equipped with multiple power receiving devices 200, there may be multiple points at which the current value is partially at a maximum, as shown in FIG. 9. Therefore, it is necessary to appropriately determine that the peak current value has been passed. This can be done, for example, by detecting that the absolute value of the rate of change of the current value up to the point at which the current value is partially at a maximum is approximately the same as the absolute value of the rate of change of the current value after the current value has reached the partial maximum.

Figure 10 is a conceptual diagram for explaining the driving and stopping of the power transmission device 100 by the power transmission control device 120 according to a modified example. The configuration of Figure 10 is the same as the configuration of Figure 7.

As shown in FIG. 10, even if the vehicle 20 has multiple power receiving devices, the power transmitting device 100 can be appropriately driven and stopped in the same way as when the vehicle 20 has one power receiving device 200 (FIG. 7).

2. Second embodiment.
The power transmission system 10 according to the second embodiment differs from the first embodiment in the processing executed by the power transmission control device 120. The configuration of the power transmission system 10 and the characteristics of the current flowing through the power distribution system 111 are the same as those described in Fig. 1 to Fig. 4. Hereinafter, the matters already described in the above content will be omitted as appropriate, and the processing executed by the power transmission control device 120 according to the second embodiment will be described.

2-1. Processing Executed by the Power Transmission Control Device Figures 11 and 12 are flowcharts showing processing executed by the power transmission control device 120 according to the second embodiment. Note that A and B shown in Figures 11 and 12 correspond to each other between Figures 11 and 12, and Figures 11 and 12 show one flowchart. Also, the processing with the same reference numerals as those in the flowcharts shown in Figures 5 and 6 is equivalent to the processing described in Figures 5 and 6.

The process performed by the power transmission control device 120 according to the second embodiment differs from the process performed by the power transmission control device 120 according to the first embodiment shown in Figures 5 and 6 in the process from step S130 onwards. When the standard value is less than a predetermined threshold value k3, the power transmission control device 120 according to the second embodiment stops the power transmission device 100ni and drives the power transmission device 100n(i+1). The process from step S130 onwards is described below.

In step S200, the power transmission control device 120 determines whether the standard value calculated in step S130 is less than a predetermined threshold value k3. The threshold value k1 is a threshold value that is a condition for stopping the power transmission device 100ni and driving the power transmission device 100n(i+1), and is a value that is given in advance to the program. This is given experimentally, for example, so as to maximize charging efficiency. If the standard value is less than the threshold value k3 (step S200; Yes), the process proceeds to step S210. If the standard value is equal to or greater than the threshold value k3 (step S200; No), the process returns to step S110 and the process is repeated.

In step S210, the power transmission control device 120 stops the power transmission device 100ni. It also sets the peak current value storage flag to 0. After step S210, the process proceeds to step S220.

In step S220, the power transmission control device 120 determines whether the power transmission device 100ni is the terminal end. If the power transmission device 100ni is the terminal end (step S220; Yes), the process ends. If the power transmission device 100ni is not the terminal end (step S220; No), the process proceeds to step S230.

In step S230, the power transmission control device 120 drives the power transmission device 100n(i+1). After step S230, the process proceeds to step S240.

In step S240, the power transmission control device 120 increments i. After step S240, the process returns to step S110 and repeats the process.

By the above-described process, the power transmission control device 120 according to the second embodiment can appropriately drive and stop each power transmission device 100 with respect to the passing position of the vehicle 20. FIG. 13 is a conceptual diagram for explaining the driving and stopping of the power transmission device 100 by the power transmission control device 120 according to the second embodiment. FIG. 13 shows a case where the vehicle 20 passes the power transmission device 100n2 that is in operation. In the order in which the vehicle 20 passes the power transmission device 100n2, (a) and (b) show graphs of current values or standard values, and conceptual diagrams showing the passing position of the vehicle 20 and the state (driven or stopped) of the power transmission device 100. The vertical axis of the graph (a) is the current value, and the vertical axis of the graph (b) is the standard value.

In (a), the power transmission control device 120 acquires the current value of the power distribution system 111a connected to the power transmission device 100n2 (step S110 (i=2)). Then, the power transmission control device 120 determines that the current value has passed the peak current value (step S121) and stores the peak current value (step S122).

In (b), the power transmission control device 120 acquires the current value of the power distribution system 111a connected to the power transmission device 100n2 (step S110 (i=2)) and calculates the standard value (step S130). Then, the power transmission control device 120 determines that the standard value is less than the threshold value k3 (step S200), stops the power transmission device 100n2, and drives the power transmission device 100n3. At this time, since the power transmission device 100n2 and the power transmission device 100n3 are connected to different power distribution systems 111, the characteristics of the acquired current value are not affected by this switching.

2-2. Modifications As with the power transmission control device 120 according to the first embodiment, the power transmission control device 120 according to the second embodiment may be used for a mobile object including a plurality of power receiving devices 200. In this case, the configuration, the current flowing through the power distribution system, and the driving and stopping of the power transmitting device 100 are the same as those described in the modification of the first embodiment, and therefore the description thereof will be omitted.

3. Third embodiment The power transmission system 10 according to the third embodiment differs from the first and second embodiments in the processing executed by the power transmission control device 120. The configuration of the power transmission system 10 and the characteristics of the current flowing through the power distribution system 111 are the same as those described in Fig. 1 to Fig. 4. Hereinafter, the matters already described in the above content will be omitted as appropriate, and the processing executed by the power transmission control device 120 according to the third embodiment will be described.

The process executed by the power transmission control device 120 according to the third embodiment is basically the same as the process executed by the power transmission control device 120 according to the first embodiment (FIGS. 5 and 6). However, the process of step S150 is different. The process executed by the power transmission control device 120 according to the third embodiment will be described below with reference to the flowcharts shown in FIG. 5 and FIG. 6.

The power transmission control device 120 according to the third embodiment executes the following process before executing the process of step S150. From the peak current value stored in step S122, the peak current value of the current flowing in the power distribution system 111 to which the power transmission device 100n(i+1) is connected is estimated. Then, the current value flowing in the power distribution system 111 to which the power transmission device 100n(i+1) is connected is acquired, and a second standard value is calculated by dividing the current value by the estimated peak current value.

As a process corresponding to step S150, the power transmission control device 120 according to the third embodiment determines whether the second standard value is equal to or greater than a predetermined threshold value k4. If the second standard value is equal to or greater than the threshold value k4, the process proceeds to step S160, where the power transmission device 100ni is stopped. If the second standard value is less than the threshold value k4, the process returns to step S110, and the process is repeated.

In the power transmission control device 120 according to the first embodiment, the standard value in step S150 usually has a small absolute value. For this reason, the judgment in step S150 (stop judgment of the power transmission device 100ni) is likely to vary widely. Therefore, the power transmission control device 120 according to the third embodiment uses the second standard value as the process corresponding to step S150. This makes it possible to reduce the variation in the stop judgment of the power transmission device 100ni.

4. Effects As described above, in the power transmission system 10 according to the present embodiment, the power transmission control device 120 controls the driving and stopping of each power transmission device 100 based on the standard value. This makes it possible to appropriately drive and stop each power transmission device even when the gap related to the vehicle 20 or the deviation in the vehicle width direction is different.

Although the above description is directed to a vehicle 20, the same effect can be obtained by suitably applying this embodiment to moving bodies other than a vehicle 20. In other words, even if a positional deviation occurs, it is possible to appropriately drive and stop each power transmission device with respect to the passing position of the moving body.

REFERENCE SIGNS LIST 10 Power transmission system 20 Vehicle 30 Power source RD Road 100 Power transmission device 101 Drive unit 110 Inverter 111 Power distribution system 120 Power transmission control device 130 Sensor 200 Power receiving device 210 Battery

Claims (5)

A power transmission system that transmits power to a power receiving device provided in a mobile object in a non-contact manner,
A plurality of power transmission devices arranged in series on a moving path of the moving object;
A plurality of inverters that convert power from a power source and supply the power to the power transmission device via a power distribution system;
a power transmission control device that controls at least one of driving and stopping of each of the power transmission devices;
A plurality of sensors each detecting a current flowing through the power distribution system associated with each of the inverters;
Equipped with
Each of the power transmitting devices is
The power transmission device is connected to a power distribution system other than the power distribution system to which the power transmission device is connected,
The power transmission control device includes:
Detecting a peak current value, which is a maximum value of a current flowing in the power distribution system;
a peak current value of a current flowing through the power distribution system, the peak current value being used to normalize the current flowing through the power distribution system, and the power transmission devices being controlled to at least one of start and stop. The power transmission control device includes:
At least one of driving and stopping of each of the power transmission devices is controlled by comparing a threshold value given as a condition for driving or stopping the power transmission devices with the standard value.
The power transmission system according to claim 1 . The standard value is a value obtained by standardizing the current value based on the minimum value and the peak current value of the current flowing through the power distribution system.
3. The power transmission system according to claim 1 or 2.
The standard value is the current value divided by the peak current value.
3. The power transmission system according to claim 1 or 2. A power transmission system that transmits power to a power receiving device provided in a mobile object in a non-contact manner,
A plurality of power transmission devices arranged in series on a moving path of the moving object;
an inverter that converts power from a power source and supplies the power to each of the power transmission devices via a power distribution system;
a power transmission control device that controls at least one of driving and stopping of each of the power transmission devices;
A sensor for detecting a current flowing in the power distribution system;
Equipped with
The power transmission control device includes:
Detecting a peak current value, which is a maximum value of a current flowing in the power distribution system;
At least one of driving and stopping of each of the power transmission devices is controlled based on a standard value obtained by standardizing a current value of a current flowing through the power distribution system using the peak current value.
A power transmission system comprising:

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