Interleaved hybrid switch network of ground side coils for dynamic wireless power transfer

Methods, systems, and apparatus for wirelessly providing power to a vehicle. The system includes a plurality of ground-side wireless power transfer devices each configured to automatically provide power to a counterpart vehicle-side wireless power transfer device. The system includes a switch connecting a power source to the plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position. The system includes a vehicle position sensor configured to detect the vehicle being within a range of the plurality of ground-side wireless power transfer devices. The system includes a switch driver configured to move the switch from the open position to the closed position when the vehicle position sensor detects the vehicle being within the range, and move the switch from the closed position to the open position when the vehicle position sensor does not detect the vehicle being within the range.

BACKGROUND

This specification relates to a system and a method for wirelessly transferring power from a ground-side power source to a vehicle.

2. Description of the Related Art

Some vehicles may be fully electric or partially electric vehicles. These vehicles may store charge in one or more batteries onboard the vehicle. These batteries may take a significant amount of time to charge, and in some cases, may limit the appeal and usage of an electric vehicle. For example, if an electric vehicle has a range of 300 miles on a single charge, the operator of the electric vehicle must make a stop to charge the vehicle if the operator wishes to drive the vehicle more than 300 miles on a single trip. This aspect of electric vehicle operation may be unappealing to some people. In addition, batteries in an electric vehicle may represent a significant portion of the cost and weight associated with a vehicle.

Dynamic wireless power transfer attempts to transmit electrical power to an electric vehicle while the vehicle is moving. However, these systems have significant cost and efficiency shortcomings. Accordingly, there is a need for a cost effective and efficient system where electric vehicles are less reliant on batteries to store large amounts of electrical power.

SUMMARY

What is described is a system for wirelessly providing power to a vehicle. The system includes a plurality of ground-side wireless power transfer devices each having a coil and an impedance matching circuit, each ground-side wireless power transfer device configured to automatically provide power to a counterpart vehicle-side wireless power transfer device. The system also includes a switch connecting a power source to the plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position. The system also includes a vehicle position sensor configured to detect the vehicle being within a range of the plurality of ground-side wireless power transfer devices. The system also includes a switch driver connected to the vehicle position sensor and the switch and configured to move the switch from the open position to the closed position when the vehicle position sensor detects the vehicle being within the range of the plurality of ground-side wireless power transfer devices, and move the switch from the closed position to the open position when the vehicle position sensor does not detect the vehicle being within the range of the plurality of ground-side wireless power transfer devices.

Also described is a system for wirelessly providing power to a vehicle. The system includes a first plurality of ground-side wireless power transfer devices. The system also includes a second plurality of ground-side wireless power transfer devices, each ground-side wireless power transfer device from the first plurality of ground-side wireless power transfer devices and the second plurality of ground-side wireless power transfer devices having a coil and an impedance matching circuit and being configured to automatically provide power to a counterpart vehicle-side wireless power transfer device, the first plurality of ground-side wireless power transfer devices and the second plurality of ground-side wireless power transfer devices arranged in an interleaved pattern along a surface to be traversed by the vehicle. The system also includes a first switch connecting a power source to the first plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position. The system also includes a second switch connecting the power source to the second plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position. The system also includes a vehicle position sensor configured to detect the vehicle being within a range of the first plurality of ground-side wireless power transfer devices and the second plurality of ground-side wireless power transfer devices. The system also includes a switch driver. The switch driver is configured to move at least one of the first switch or the second switch from the open position to the closed position when the vehicle position sensor detects the vehicle being within the range of the first plurality of ground-side wireless power transfer devices and the second plurality of ground-side wireless power transfer devices. The switch driver is also configured to move at least one of the first switch or the second switch from the closed position to the open position when the vehicle position sensor does not detect the vehicle being within the range of the first plurality of ground-side wireless power transfer devices and the second plurality of ground-side wireless power transfer devices.

Also described is a method for wirelessly providing power to a vehicle. The method includes providing a plurality of ground-side wireless power transfer devices each having a coil and an impedance matching circuit, each ground-side wireless power transfer device configured to automatically provide power to a counterpart vehicle-side wireless power transfer device. The method also includes providing a switch connecting a power source to the plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position. The method also includes detecting, by a vehicle position sensor, the vehicle being within a range of the plurality of ground-side wireless power transfer devices. The method also includes moving, by a switch driver connected to the vehicle position sensor and the switch, the switch from the open position to the closed position when the vehicle position sensor detects the vehicle being within the range of the plurality of ground-side wireless power transfer devices, and moving the switch from the closed position to the open position when the vehicle position sensor does not detect the vehicle being within the range of the plurality of ground-side wireless power transfer devices.

DETAILED DESCRIPTION

Disclosed herein are systems, vehicles, and methods for automatically providing electrical power to an electrical vehicle via a wireless power transfer system. Dynamic wireless power transfer (DWPT) refers to the technology of transferring energy to a moving vehicle. The transferred energy may be used to power the vehicle directly, or to charge an energy storage device onboard the vehicle, such as a battery. DWPT reduces or eliminates the range anxiety associated with operating and owning an electric vehicle. DWPT also may reduce the weight or the cost of the vehicle by allowing for reduced sizes of energy storage devices onboard the vehicle.

A significant obstacle for implementation of DWPT is a high system cost of the ground-side power architecture. Conventionally, the ground-side power architecture either required many components, rendering it expensive to build and maintain, or was not efficient in power usage, rendering it expensive to operate. The systems and methods disclosed herein provide an improved ground-side power system with fewer parts than conventional systems, and more efficient operations as compared to conventional systems.

To properly and efficiently power the ground-side coils, sensors and switches may be used to turn on and off the individual transmitter coils. However, sensors and switches have high cost, so use of fewer sensors and switches is preferable and desirable.

The system described herein is a combination of a switch controlled system and an automatic power transfer system. The combination reduces the collective inefficiencies and drawbacks of using only a switch controlled system or using only an automatic power transfer system, resulting in a cost-effective, easily maintainable, and operationally efficient system for dynamically powering electric vehicles.

The switches used in the interleaved hybrid switch dynamic wireless power transfer system control groups of coils instead of individual coils, and turns on the groups of coils based on the relative location of the vehicle. When a particular group of coils is turned on, they do not transmit electrical power until they are automatically coupled with a vehicle-side coil using an impedance matching circuit. The system has many advantages over a switch controlled system or a switchless system. Compared to a switched system, the interleaved hybrid switch dynamic wireless power transfer system has a fewer number of switches, drivers, and sensors. Also, it is more energy efficient than a switched system because the current in each coil is automatically determined by magnetic coupling and only transmitted when the vehicle is present to receive the electrical power.

The sensors used in the interleaved hybrid switch dynamic wireless power transfer system may be more cost effective than sensors used in other systems because the sensors used in other systems may have higher sensitivity or accuracy or latency demands, as those sensors may be used to trigger individual coils. The sensors of the interleaved hybrid switch dynamic wireless power transfer system are used to trigger a group of coils, so sensitivity/accuracy/latency may not be as important.

FIG. 1illustrates an example situation with a vehicle using the interleaved hybrid switch dynamic wireless power transfer system.

The vehicle104may be a fully or partially electric vehicle powered by a motor/generator. The vehicle104may store electrical energy in a battery for use by the motor/generator. The vehicle104may have an automatic or manual transmission. The vehicle104is a conveyance capable of transporting a person, an object, or a permanently or temporarily affixed apparatus. The vehicle104may be a self-propelled wheeled conveyance, such as a car, a sports utility vehicle, a truck, a bus, a van or other motor or battery driven vehicle. For example, the vehicle104may be an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a fuel cell vehicle, or any other type of vehicle that includes a motor/generator. Other examples of vehicles include bicycles, trains, planes, or boats, and any other form of conveyance that is capable of transportation. The vehicle104may be a semi-autonomous vehicle or an autonomous vehicle. That is, the vehicle104may be self-maneuvering and navigate without human input. An autonomous vehicle may use one or more sensors and/or a navigation unit to drive autonomously.

The vehicle104may receive electrical power to be used to propel the vehicle104from ground-side wireless power transfer devices108. The ground-side wireless power transfer devices108may be located on a road to be traversed by the vehicle104so that the vehicle104may be provided with electrical power as the vehicle104traverses the road. The electrical power may be used immediately by the motor/generator or any other component powered by electricity of the vehicle104, or the electrical power may be stored in one or more batteries of the vehicle104.

Generally, multiple segmented coils are preferable to a single elongated coil because the multiple segmented coils have a lower radiated electromagnetic interference (EMI) and a higher energy transfer efficiency.

When the vehicle104is in range of a set102of ground-side wireless power transfer devices108, the vehicle104may receive electrical power from that particular set102of ground-side wireless power transfer devices108. For example, as shown inFIG. 1, the vehicle104is within a range of the first set102A of ground-side wireless power transfer devices108A-108D, and may receive electrical power from any one of the ground-side wireless power transfer devices108. As further shown inFIG. 1, the vehicle104is located above a ground-side wireless power transfer device108B, and the ground-side wireless power transfer device108B is providing electrical power to the vehicle-side wireless power transfer device124.

The ground-side wireless power transfer device108may transfer electrical power automatically to the vehicle-side wireless power transfer device124using magnetic coupling110. The ground-side wireless power transfer device108and the vehicle-side wireless power transfer device124may each have coils and power architectures configured to automatically determine the current in the ground-side coil and transmit electrical power from the ground-side wireless power transfer device108to the vehicle-side wireless power transfer device124. For example, the vehicle-side wireless power transfer device124may have a coil112configured to receive the electrical power from a corresponding coil of the ground-side wireless power transfer device108and a vehicle-side power architecture106configured to process the electrical power received via the coil112for storage or use by the vehicle104.

When the vehicle104is within a range of the first set102A of ground-side wireless power transfer devices108A-108D, all of the ground-side wireless power transfer devices108A-108D in the first set102A may be activated and ready to transmit electrical power to the vehicle104. In some embodiments, the range is between 0.1 meters (m) and10m. In some embodiments, a ground-side wireless power transfer device108is ready to transmit electrical power when electrical current is run through the ground-side wireless power transfer device108. Accordingly, the ground-side wireless power transfer device108may be deactivated or not ready to transmit electrical power when electrical current is not being run through the ground-side wireless power transfer device108.

In order to conserve electricity, a set102of ground-side wireless power transfer devices108may not be made ready to transfer electrical power until a vehicle104is detected as being within the range of the set102. Accordingly, when no vehicle is detected as being within the range of the set102, the set102of ground-side wireless power transfer devices108may be deactivated and unable to provide electrical power. By selectively activating and deactivating sets102of ground-side wireless power transfer devices108, the system100conserves the electrical energy which would have been run through ground-side wireless power transfer devices108having no vehicle in range to potentially transmit electrical power to. For example, as shown inFIG. 1, the second set102B of ground-side wireless power transfer devices108E-108H may not have electrical current provided to them, as no vehicle is within the range of the second set102B. By deactivating the second set102B when no vehicle is within the range, electrical energy may be conserved.

The vehicle104may be detected as being within the range of a particular set of ground-side wireless power transfer devices in any number of active or passive ways, using a vehicle position sensor. The vehicle104may constantly transmit vehicle location data from a transceiver116. The vehicle location data may indicate the location of the vehicle104in space. The vehicle position sensor may be an antenna114configured to receive the vehicle location data from the vehicle104and determine that the vehicle104is within the range of a particular set of ground-side wireless power transfer devices. For example, the vehicle104may have a transceiver116configured to transmit vehicle location data to be received by the vehicle position sensor (e.g., antenna114A) on the side of the road. The vehicle position sensor may analyze the vehicle location data and determine that the vehicle104is located within the range of the first set102A of ground-side wireless power transfer devices108A-108D, and they may be activated so that electrical power may be provided to the vehicle104when the vehicle104drives over any ground-side wireless power transfer device108of the first set102A of ground-side wireless power transfer devices108A-108D.

In some embodiments, the vehicle position sensor may not be located within the range of its corresponding set of ground-side wireless power transfer devices108, and may be located at a prior location along the road, such that when the vehicle position sensor detects the location of the vehicle104, based on the speed of the vehicle104(which may be detected by the vehicle position sensor) the appropriate set of ground-side wireless power transfer devices may be later activated based on an anticipated arrival of the vehicle104.

There may be one vehicle location sensor per set102of ground-side wireless power transfer devices108. The vehicle104leaving the range of a set102of ground-side wireless power transfer devices108may be detected when the vehicle location sensor no longer receives vehicle position data from the vehicle transceiver116or when the vehicle position data received from the vehicle transceiver116indicates the vehicle104is no longer in the range of the set102of ground-side wireless power transfer devices108. When the vehicle104leaves the range of the set102of ground-side wireless power transfer devices108, the corresponding ground-side wireless power transfer devices108may be deactivated to conserve energy.

In some embodiments, the vehicle position sensor is an antenna114configured to receive vehicle position data, as described herein. In some embodiments, the vehicle position sensor is a weight sensor118configured to detect a vehicle104entering the range of a set102of ground-side wireless power transfer devices108based on a detected weight of the vehicle104. A corresponding weight sensor126may be used to detect when the vehicle exits the range of the set102of ground-side wireless power transfer devices108. When the vehicle104leaves the range of the set102of ground-side wireless power transfer devices108, the corresponding ground-side wireless power transfer devices108may be deactivated to conserve energy.

In some embodiments, the vehicle position sensor is a movement detection sensor120, such as RADAR or LIDAR, configured to detect when the vehicle104enters the range of a set102of ground-side wireless power transfer devices108based on movement of the vehicle104. A corresponding location detection sensor122may be located at the end of the set102of ground-side wireless power transfer devices108to detect when the vehicle104leaves the range of the set102of ground-side wireless power transfer devices108. When the vehicle104leaves the range of the set102of ground-side wireless power transfer devices108, the corresponding ground-side wireless power transfer devices108may be deactivated to conserve energy.

In some embodiments, the vehicle position sensor includes a camera configured to detect image data, and the vehicle position sensor is configured to perform image processing to determine whether the vehicle104is in the range of a set102of ground-side wireless power transfer devices108. The vehicle position sensor may use deep machine learning trained by a set of training images to learn to detect vehicles. In some embodiments, the vehicle position sensor is a computing device with a processor and a memory and configured to perform the functions described herein. The memory may be a non-transitory computer readable memory configured to store instructions for the processor of the vehicle position sensor.

Any combination of devices and methods for detecting the presence of the vehicle104in a range of a set102of ground-side wireless power transfer devices108may be used. For example, an antenna114may be used with a weight sensor118, so that vehicles having a transceiver116can be detected and vehicles without a transceiver116may be detected as well.

The vehicle104may include one or more computers or electronic control units (ECUs), appropriately programmed, to control one or more operations of the vehicle104, including providing vehicle location data to the transceiver116.

A vehicle lacking vehicle-side wireless power transfer device124(e.g., a conventional internal combustion engine vehicle) may be unaffected by the presence of the ground-side wireless power transfer devices108underneath it.

The system described herein is a combination of a switched system approach and a switchless, automatic system approach. A switched system approach may include detection of a vehicle by a sensor, and turning on transmission of ground-side electrical power by a switch. These ground-side transmission systems may constantly emit electrical power via a coil while activated. These switched systems require many switches and sensors to individually turn coils on and off. A switchless system approach may include impedance matching circuits (a combination of inductors and capacitors) between a coil and the power source. A coupling of the vehicle-side coils and the ground-side coils automatically determines the current in the ground-side coil, and power transfer is achieved automatically, without a need for switches. However, with this switchless approach, a current is constantly run through the uncoupled ground-side coils, and contributes to conduction loss in the coil and degrades system efficiency. The system described herein uses impedance matching circuits and a reduced number of sensors and switches, as compared to a switched system approach, in order to maximize efficiency and minimize cost.

According to the arrangement200, the ground-side wireless power transfer devices108of a set102are all connected to a single inverter206. For example, the ground-side wireless power transfer devices108of the first set102A are all connected to a first inverter206A and the ground-side wireless power transfer devices108of the second set102B are all connected to a second inverter206B.

The inverter206is configured to convert low-frequency AC power (e.g., 50-60 Hz) received from an AC power source, such as an AC grid212, into high-frequency AC power (e.g., 80 kHz) capable of being transmitted by the ground-side wireless power transfer devices108. This generates the magnetic field between the ground-side coil202and the vehicle-side coil112to be coupled together. The high-frequency AC power is received by the vehicle-side coil112, and the vehicle-side power architecture106is configured to convert the received high-frequency AC power into DC power to be stored by the battery of the vehicle104. In some embodiments, the inverter206is a high-frequency inverter. The inverter206is connected to each of the ground-side wireless power transfer devices108in the particular set102. The inverter206is also connected to a switch208.

The switch208is configured to have an open state and a closed state. In the open state, the switch208disconnects the ground-side wireless power transfer devices108from the AC grid212. In the closed state, the switch208connects the ground-side wireless power transfer devices108to the AC grid212. The switch208may be a physical switch, such as a contactor, a relay, or a circuit breaker, or any kind of command or program that governs the operation(s) of the inverter.

The switch208is connected to a switch driver210. The switch driver210is connected to the vehicle location sensor (illustrated as an antenna114, but it may be any sensor, as described herein). When the vehicle location sensor detects a vehicle within the range of the set102of the ground-side wireless power transfer devices108, the vehicle location sensor communicates a signal to the switch driver210to move the switch208from the open state to the closed state, to provide the ground-side wireless power transfer devices108with electrical power from the AC grid212(via the inverter206).

In some embodiments, when the vehicle location sensor detects that the vehicle is no longer within the range of the set102of ground-side wireless power transfer devices108, the vehicle location sensor communicates a signal to the switch driver210to move the switch208from the closed state to the open state, in order to conserve electrical energy when the ground-side wireless power transfer devices108are not being used.

In some embodiments, the switch driver210may automatically move the switch208from the closed state to the open state after a predetermined period of time has elapsed. In some embodiments, the switch driver210is communicatively coupled to the ground-side wireless power transfer devices108, and the ground-side wireless power transfer devices108may be capable of detecting when they are transmitting electrical power to a vehicle. In these embodiments, when the ground-side wireless power transfer devices108indicate to the switch driver210that they are not transmitting electrical power to a vehicle, the switch driver210may move the switch208from the closed position to the open position.

The switch driver210may be a computing device with a processor and a memory and configured to perform the functions described herein. The memory may be a non-transitory computer readable memory configured to store instructions for the processor of the switch driver210.

Each ground-side wireless power transfer device has a coil202and an impedance matching circuit204. The impedance matching circuit204may be a combination of inductors and capacitors, which uses the reactance reflected by the receiver to automatically increase the field strength in coupled portions of the transmitter-receiver system, allowing for efficient power transfer. As a result, when a receiver (on the vehicle104) and a transmitter (ground-side coil202) are coupled by being in proximity to each other, the impedance matching circuit204allows for current to automatically be generated to facilitate providing of electrical power from the ground-side wireless power transfer device to the vehicle104.

While an antenna114is shown in the drawings, any other device or sensor may be used to detect the presence of a vehicle within a range of the set102of ground-side wireless power transfer devices108, such as a weight sensor118or a movement detection sensor120or a camera. The other device or sensor may be used instead of or in addition to the antenna114.

In an example situation, a vehicle104equipped with a vehicle-side wireless power transfer device124is travelling down a road, approaching the first set102A of ground-side wireless power transfer devices108. The first vehicle location sensor (e.g., antenna114A) detects the vehicle104and communicates an indication to the first switch driver210A to move the first switch208A from the open position to the closed position. The first switch208A moves from the open position to the closed position, and electrical energy is provided from the AC grid212to the first inverter206A, which converts low-frequency AC power to high-frequency AC power. The converted high-frequency AC power is then provided to the ground-side wireless power transfer devices108. The ground-side wireless power transfer devices108automatically transfer electrical energy to the vehicle104, as the vehicle104is travelling along the road, when the vehicle-side wireless power transfer device124is within a power transfer range of a ground-side wireless power transfer device108in the first set102A. The vehicle-side wireless transfer device124receives the high-frequency AC power, converts the high-frequency AC power into DC power, and stores the DC power in a battery.

When the vehicle104is no longer in the range of the first set102A of ground-side wireless power transfer devices108, the first vehicle location sensor (e.g., antenna114A) may detect this and alert the first switch driver210A, which communicates an instruction to the first switch208A to move from the closed state to the open state. In other embodiments, the first switch driver210A may automatically communicate the instruction to the first switch208A to move from the closed state to the open state after a period of time has elapsed.

The vehicle104may approach the second set102B of ground-side wireless power transfer devices108, and the process may repeat again, with the second vehicle location sensor (e.g., antenna114B), the second switch driver210B, the second switch208B, and the second inverter206B. The AC grid212providing the AC power to the ground-side wireless power transfer devices108of the first set102A may be the same source or a different source than that of the second set102B.

FIG. 3Aillustrates an arrangement300of the ground-side wireless power transfer devices of a particular set102. The ground-side wireless power transfer devices301-306each have a coil311-316and may each have an impedance matching circuit371-376.

The ground-side wireless power transfer devices301-306(substantially similar to ground-side wireless power transfer devices108) within a given set102may be arranged in different ways. As illustrated inFIG. 2, the ground-side wireless power transfer devices301-306of a particular set102may all be connected to a single common inverter. For example, inFIG. 2, the ground-side wireless power transfer devices108of the first set102A are all connected to the first inverter206A.

Alternatively, as shown inFIG. 3A, the ground-side wireless power transfer devices of a particular set102may be divided into two subsets, an odd numbered subset (ground-side wireless power transfer devices301,303, and305) and an even numbered subset (ground-side wireless power transfer devices302,304, and306), with each subset having its own inverter. The ground-side wireless power transfer devices301-306of the two subsets may be arranged in an interleaved manner, as shown inFIGS. 3A, 4, 5, and 6.

By arranging the ground-side wireless power transfer devices in an interleaved manner, a number of advantages may be achieved. When the system needs maintenance and the ground-side wireless power transfer devices are interleaved, one subset of ground-side wireless power transfer devices108may be down, but the other subset may be active and able to provide power to vehicles. For example, if the first ground-side wireless power transfer device301is in need of repair, the odd numbered subset (e.g., ground-side wireless power transfer devices301,303, and305) and the first inverter321may be deactivated while the first ground-side wireless power transfer device301is being repaired. During this time, the even numbered subset (e.g., ground-side wireless power transfer devices302,304, and306) may remain operational and able to provide electrical power to vehicles in the range of the set102of ground-side wireless power transfer devices.

Further, when the ground-side wireless power transfer devices are in an interleaved manner, the subsets of ground-side wireless power transfer devices may be selectively activated to even out wear and usage of the ground-side wireless power transfer devices of the set. For example, if the even numbered ground-side wireless power transfer devices ofFIG. 3A(e.g.,302,304, and306) were used more frequently than the odd numbered ground-side wireless power transfer devices (e.g.,301,303, and305), the next time a vehicle is detected in the range of the ground-side wireless power transfer devices, the odd numbered ground-side wireless power transfer devices may be used.

Each subset of ground-side wireless power transfer devices is connected to a respective inverter, resulting in two inverters for the set of ground-side wireless power transfer devices. As shown inFIG. 3A, the odd numbered subset is connected to a first inverter321, and the even numbered subset is connected to a second inverter322. This is in contrast with the sets102A and102B shown inFIG. 2, which each have one inverter206per set102.

The first inverter321converts low-frequency AC power received from the AC grid360to high-frequency AC power and provides the high-frequency AC power to the odd numbered subset of ground-side wireless power transfer devices. The second inverter322converts low-frequency AC power received from the AC grid360to high-frequency AC power and provides the high-frequency AC power to the even numbered subset of ground-side wireless power transfer devices.

When the vehicle position sensor (e.g., antenna350) detects the presence of a vehicle in the range of the set102, as described herein, the vehicle position sensor (e.g., antenna350) communicates an indication to the switch driver340that a vehicle is within the range.

The switch driver340receives the indication that a vehicle is within the range and determines whether to open or close the first switch331and whether to open or close the second switch322. When the first switch is in the open position, electrical power does not flow to the odd numbered subset of ground-side wireless power transfer devices, and when the first switch is in the closed position, electrical power flows to the odd numbered subset of ground-side wireless power transfer devices. Similarly, when the second switch is in the open position, electrical power does not flow to the even numbered subset of ground-side wireless power transfer devices, and when the second switch is in the closed position, electrical power flows to the even numbered subset of ground-side wireless power transfer devices.

The switch driver340may communicate instructions to the first switch331and the second switch332such that only the first switch331is in the closed position, only the second switch332is in the closed position, both the first switch331and the second switch332are in the open position, or both the first switch331and the second switch332are in the closed position.

FIG. 3Billustrates the switch driver340ofFIG. 3A. The switch driver340ofFIG. 3Bmay also be used as the switch driver210ofFIG. 2. The switch driver340includes a processor342configured to execute instructions stored on a non-transitory memory344. Any of the actions of the switch driver340described herein may be performed by the processor342. The switch driver340also includes a transceiver346communicatively coupled to a remote data server348. The remote data server348may be a source of traffic data, location data, environmental data, topographical data, map data, and any other data pertinent to the usage of the ground-side wireless power transfer devices. The transceiver346may be configured to communicate data over a wireless data network, such as a cellular network or Wi-Fi network.

The switch driver340may store in the memory344a count of the usage of each subset of ground-side wireless power transfer devices, and the switch driver340may determine which switch to open and which switch to close based on the usages. In some embodiments, the switch driver340may level out the usage of each subset. In some embodiments, the switch driver340may be aware of an imminent planned maintenance of a particular subset and leading up to the planned maintenance, the particular subset may be used more often than the other subset(s), as it is going to be maintained imminently.

The switch driver340may receive traffic data from the remote data server348via the transceiver346. When the traffic data indicates that there is heavy traffic in the range of the ground-side wireless power transfer devices of the set102, the switch driver340may move all of the switches to the closed position when a vehicle is in the range, such that all of the subsets of ground-side wireless power transfer devices are activated and able to transmit electrical power. When the traffic data indicates that there is sparse traffic in the range of the ground-side wireless power transfer devices of the set102, the switch driver340may only move one of the switches to the closed position, such that only one of the subsets of ground-side wireless power transfer devices are activated and able to transmit electrical power to a vehicle within the range.

The switch driver340may receive road closure data from the remote data server348via the transceiver346, and when the road closure data indicates that the road corresponding to the set of the ground-side wireless power transfer devices is closed, the switch driver340may move all switches to the open position, such that no energy is wasted.

The memory344may store a time-out period of time. The switch driver340may move all switches to the open position after the time-out period of time has elapsed. The time-out period of time may begin being counted after a vehicle is detected as being within the range of the set102of ground-side wireless power transfer devices. The time-out period of time may be set to a value where any vehicles travelling in the range of the set102of ground-side wireless power transfer devices would likely have exited the range of the set102of ground-side wireless power transfer devices within the time-out period of time.

In some embodiments, the time-out period of time may be predetermined based on the location of the set102of ground-side wireless power transfer devices and the spacing of the ground-side wireless power transfer devices from each other. In some embodiments, the time-out period of time may be adjusted dynamically based on received data, such as traffic data or weather data. For example, when traffic is heavy, the time-out period of time may be lengthened, and when the weather is such that vehicles can be expected to travel slower (e.g., snow or rain), the time-out period of time may also be lengthened.

The switch driver340may receive weather data from the remote data server348via the transceiver346, and when the weather data indicates conditions where vehicles may be expected to travel slower or vehicles may be expected to use more electrical energy, all of the subsets of ground-side wireless power transfer devices may be activated by moving all of the switches to the closed position.

The vehicle transceiver116may communicate vehicle data to the vehicle position sensor. The vehicle data may include a battery level or an electrical charge demand of the vehicle. The switch driver340may receive vehicle related data from the vehicle position sensor and activate a number of subsets of ground-side wireless power transfer devices accordingly. For example, when the vehicle data indicates that the vehicle104is very low on electrical power, more subsets of ground-side wireless power transfer devices may be activated. In another example, when the vehicle data indicates that the vehicle104is one that uses a relatively high amount of electrical energy, such as a big rig truck or a bus, more subsets of ground-side wireless power transfer devices may be activated.

In some situations, a fee may be associated with use of the ground-side wireless power transfer devices to charge the vehicle104, and a payment amount, use count, or usage permissions may be communicated as part of the vehicle data. The switch driver340may activate subsets of the ground-side wireless power transfer devices based on account information associated with the vehicle104. For example, different usage plans may be associated with use of the ground-side wireless power transfer devices, and under a first usage plan, the vehicle104may receive charge from all of the available subsets of ground-side wireless power transfer devices, and under a second usage plan, the vehicle104may receive charge from only a portion of the available subsets of ground-side wireless power transfer devices.

While two subsets are shown inFIG. 3A, any number of subsets and corresponding inverters may be used. In addition, any combination of the subsets may be used in the situations described herein. For example, when heavy traffic is detected, instead of all of the switches being moved to the closed position, as described herein, more switches than normal may be moved to the closed position. Further, while the subsets ofFIG. 3Aare shown as being alternating in arrangement (e.g., A, B, A, B, A, B), any arrangement may be used (e.g., A, B, C, D, C, B, A, B, C, D or A, B, C, D, A, B, C, D), where the letters represent different subsets of ground-side wireless power transfer devices controlled by different switches.

FIG. 4illustrates an example scenario where only a first subset of ground-side wireless power transfer devices are activated.

The vehicle104is within the range of the set102of ground-side wireless power transfer devices301-306. The ground-side wireless power transfer devices301-306are separated into two subsets: an odd-numbered subset (ground-side wireless power transfer devices301,303,305) and an even-numbered subset (ground-side wireless power transfer devices302,304,306). The odd-numbered subset is connected to a first inverter321and the even-numbered subset is connected to a second inverter322, similar toFIG. 3A.

The vehicle104has been detected by the system, using the vehicle position sensor (e.g., an antenna, a weight sensor, a movement detection sensor, or a camera). The switch driver340has determined that the odd-numbered subset should be used, according to any of the steps/criteria described herein. The first switch (switch331ofFIG. 3A) is moved from the open position to the closed position, and the ground-side wireless power transfer devices301,303, and305are activated (as shown by the solid lines) and capable of automatically transmitting electrical power wirelessly to the vehicle104. The second switch (switch332ofFIG. 3B) remains in the open position or is moved from the closed position to the open position, and the ground-side wireless power transfer devices302,304, and306are not activated (as shown by the dashed lines).

FIG. 5illustrates a second subset of ground-side wireless power transfer devices being used by the vehicle104.

Again, the vehicle104may be detected by the system, using the vehicle position sensor. The switch driver340has, in this case, determined that the even-numbered subset should be used, according to any of the steps/criteria described herein. The second switch (switch332ofFIG. 3A) is moved from the open position to the closed position, and the ground-side wireless power transfer devices302,304, and306are activated (as shown by the solid lines) and capable of automatically transmitting electrical power wirelessly to the vehicle104. The first switch (switch331ofFIG. 3B) remains in the open position or is moved from the closed position to the open position, and the ground-side wireless power transfer devices301,303, and305are not activated (as shown by the dashed lines).

FIG. 6illustrates all subsets of ground-side wireless power transfer devices being used by the vehicle104.

Again, the vehicle104may be detected by the system, using the vehicle position sensor. The switch driver340has, in this case, determined that both the odd-numbered subsets and the even-numbered subset should be used, according to any of the steps/criteria described herein. The first switch (switch331ofFIG. 3A) and the second switch (switch332ofFIG. 3A) is moved from the open position to the closed position, and the ground-side wireless power transfer devices301-306are activated (as shown by the solid lines) and capable of automatically transmitting electrical power wirelessly to the vehicle104.

FIG. 7is a flowchart of a process700of the system, according to some embodiments of the invention.

A plurality of ground-side wireless power transfer devices108each having a coil202and an impedance matching circuit204are provided (step702). The plurality of ground-side wireless power transfer devices108may be positioned within a ground surface of the road such that vehicles drive over the ground-side wireless power transfer devices108. As described herein, the plurality may be a set102of ground-side wireless power transfer devices108. Each ground-side wireless power transfer device108is configured to automatically provide power to a counterpart vehicle-side wireless power transfer device124.

A switch connecting a power source to the plurality of ground-side wireless power transfer devices and configured to be in an open position or a closed position is provided (step704). The switch may also be located within the ground surface of the road, or may be located on the side of the road.

A vehicle position sensor detects the vehicle104being within the range of the plurality of ground-side wireless power transfer devices108(step706). As described herein, the vehicle position sensor may be an antenna114, a weight sensor118, a movement detection sensor120, or an image sensor, such as a camera.

A switch driver210connected to the vehicle position sensor and the switch208moves the switch208from the open position to the closed position when the vehicle position sensor detects the vehicle104being within range of the plurality of ground-side wireless power transfer devices108(step708). The switch driver210also moves the switch208from the closed position to the open position when the vehicle position sensor does not detect the vehicle104being within the range of the plurality of ground-side wireless power transfer devices108(step708).

Electrical power from a power source is provided to an inverter206when the switch208is moved from the open position to the closed position (step710). The inverter206converts low-frequency AC power from the power source into high-frequency AC power to be transmitted by the plurality of ground-side wireless power transfer devices108when the switch208is moved from the open position to the closed position (step712).

The vehicle position sensor may detect the vehicle104exiting the range of the plurality of ground-side wireless power transfer devices108and the switch driver210moves the switch208from the closed position to the open position (step714).