U.S. patent application number 13/612494 was filed with the patent office on 2013-03-14 for reconfigurable control architectures and algorithms for electric vehicle wireless energy transfer systems.
This patent application is currently assigned to WiTricity Corporation. The applicant listed for this patent is Ron Fiorello, Katherine L. Hall, Morris P. Kesler, Herbert Toby Lou, Simon Verghese. Invention is credited to Ron Fiorello, Katherine L. Hall, Morris P. Kesler, Herbert Toby Lou, Simon Verghese.
Application Number | 20130062966 13/612494 |
Document ID | / |
Family ID | 47829204 |
Filed Date | 2013-03-14 |
United States Patent
Application |
20130062966 |
Kind Code |
A1 |
Verghese; Simon ; et
al. |
March 14, 2013 |
RECONFIGURABLE CONTROL ARCHITECTURES AND ALGORITHMS FOR ELECTRIC
VEHICLE WIRELESS ENERGY TRANSFER SYSTEMS
Abstract
A control architecture for electric vehicle wireless power
transmission systems that may be segmented so that certain
essential and/or standardized control circuits, programs,
algorithms, and the like, are permanent to the system and so that
other non-essential and/or augmentable control circuits, programs,
algorithms, and the like, may be reconfigurable and/or customizable
by a user of the system. The control architecture may be
distributed to various components of the wireless power system so
that a combination of local or low-level controls operating at
relatively high-speed can protect critical functionality of the
system while higher-level and relatively lower speed control loops
can be used to control other local and system-wide
functionality.
Inventors: |
Verghese; Simon; (Arlington,
MA) ; Kesler; Morris P.; (Bedford, MA) ; Hall;
Katherine L.; (Arlington, MA) ; Lou; Herbert
Toby; (Carlisle, MA) ; Fiorello; Ron;
(Tewksbury, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Verghese; Simon
Kesler; Morris P.
Hall; Katherine L.
Lou; Herbert Toby
Fiorello; Ron |
Arlington
Bedford
Arlington
Carlisle
Tewksbury |
MA
MA
MA
MA
MA |
US
US
US
US
US |
|
|
Assignee: |
WiTricity Corporation
Watertown
MA
|
Family ID: |
47829204 |
Appl. No.: |
13/612494 |
Filed: |
September 12, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61533281 |
Sep 12, 2011 |
|
|
|
61566450 |
Dec 2, 2011 |
|
|
|
Current U.S.
Class: |
307/104 |
Current CPC
Class: |
H02J 7/025 20130101;
Y02T 90/128 20130101; B60L 53/60 20190201; Y02T 90/121 20130101;
B60L 53/126 20190201; Y02T 10/7005 20130101; Y02T 90/12 20130101;
H02J 7/00034 20200101; Y02T 90/163 20130101; B60L 53/124 20190201;
Y02T 90/16 20130101; Y02T 10/70 20130101; Y02T 90/14 20130101; H02J
50/80 20160201; Y02T 90/122 20130101; H02J 2310/48 20200101; H02J
50/12 20160201; H02J 50/90 20160201; H02J 5/005 20130101; Y02T
10/7072 20130101; B60L 3/00 20130101 |
Class at
Publication: |
307/104 |
International
Class: |
H01F 38/14 20060101
H01F038/14 |
Claims
1. A wireless energy transfer system with a segmented control
architecture, the system comprising: a wireless energy transfer
system coupled to a primary controller; and a user configurable
secondary controller in communication with the primary controller;
wherein the primary controller performs essential control functions
for the wireless system.
2. The system of claim 1, wherein the essential control functions
of the primary controller comprise maintaining wireless energy
transfer operating safety limits.
3. The system of claim 1, wherein the essential control functions
of the primary controller comprise monitoring and controlling the
voltage and current on energy transfer components.
4. The system of claim 1, wherein the user configurable secondary
controller allows adjustment of at least one non-safety critical
parameter of the system.
5. The system of claim 1, wherein the primary controller and the
user configurable secondary controller are each physically
implemented on the same hardware.
6. The system of claim 4, wherein the user configurable secondary
controller is configurable to adjust a maximum output power of the
wireless energy transfer system.
7. The system of claim 4, wherein the user configurable secondary
controller is configurable to adjust a frequency of the wireless
energy transfer system.
8. The system of claim 4, wherein the user configurable secondary
controller is configurable to adjust the security of the wireless
energy transfer system.
9. The system of claim 1, wherein the primary controller and the
user configurable secondary controller are each virtual controllers
implemented on the same processor.
10. The system of claim 1, wherein the primary controller and the
user configurable secondary controller are each separate
processors.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
patent application 61/533,281 filed Sep. 12, 2011 and U.S.
provisional patent application 61/566,450 filed Dec. 2, 2011.
BACKGROUND
[0002] 1. Field
[0003] This disclosure relates to wireless energy transfer and
methods for controlling the operation and performance of electric
vehicle wireless power transmission systems.
[0004] 2. Description of the Related Art
[0005] Energy or power may be transferred wirelessly using a
variety of known radiative, or far-field, and non-radiative, or
near-field, techniques as detailed, for example, in commonly owned
U.S. patent application Ser. No. 12/613,686 published on May 6,
2010 as US 2010/010909445 and entitled "Wireless Energy Transfer
Systems," U.S. patent application Ser. No. 12/860,375 published on
Dec. 9, 2010 as 2010/0308939 and entitled "Integrated
Resonator-Shield Structures," U.S. patent application Ser. No.
13/222,915 published on Mar. 15, 2012 as 2012/0062345 and entitled
"Low Resistance Electrical Conductor," U.S. patent application Ser.
No. 13/283,811 published on ______ as U.S. Pat. No. ______ and
entitled "Multi-Resonator Wireless Energy Transfer for Lighting,"
the contents of which are incorporated by reference.
[0006] Recharging the batteries in full electric vehicles currently
requires a user to plug a charging cord into the vehicle. The many
disadvantages of using a charging cord, including the
inconvenience, weight, and awkwardness of the cord, the necessity
of remembering to plug-in and un-plug the vehicle, and the
potential for cords to be stolen, disconnected, damaged, etc., have
motivated makers of electric vehicles to consider wireless
recharging scenarios. Using a wireless power transmission system to
recharge an electric vehicle has the advantage that no user
intervention may be required to recharge the vehicle's batteries.
Rather, a user may be able to position a vehicle near a source of
wireless electricity and then an automatic control system may
recognize that a vehicle in need of charge is present and may
initiate, sustain, and control the delivery of wireless power as
needed.
[0007] One of the advantages of wireless recharging of electric
vehicles is that the vehicles may be recharged using a variety of
wireless power techniques while conforming to a variety of
performance criteria. The variety of available wireless power
techniques and acceptable performance criteria may present
challenges to system designers who may like to provide for
interoperability between different wireless sources and wireless
devices (usually integrated in the vehicles) and at the same time
differentiate their products by offering certain enhanced features.
Therefore there is a need for an electric vehicle wireless power
system control architecture that may ensure safe, efficient and
reliable performance that meets certain industry performance
standards and that offers designers and users of the end-system the
opportunity to customize their systems to offer differentiated and
enhanced features to the drivers of their vehicles.
SUMMARY
[0008] This invention relates to a control architecture for
electric vehicle (EV) wireless power transmission systems that may
be segmented so that certain essential and/or standardized control
circuits, programs, algorithms, and the like, are permanent to the
system and so that other non-essential and/or augmentable control
circuits, programs, algorithms, and the like, may be reconfigurable
and/or customizable by a user of the system. In addition, the
control architecture may be distributed to various components of
the wireless power system so that a combination of local or
low-level controls operating at relatively high-speed can protect
critical functionality of the system while higher-level and
relatively lower speed control loops can be used to control other
local and system-wide functionality. This combination of
distributed and segmented control may offer flexibility in the
design and implementation of higher level functions for end-use
applications without the risk of disrupting lower level power
electronics control functions.
[0009] The inventors envision that the control architecture may
comprise both essential and non-essential control functions and may
be distributed across at least one wireless source and at least one
wireless device. Non-essential control functions may be arranged in
a hierarchy so that, for example, more sophisticated users may have
access to more, or different reconfigurable control functions than
less sophisticated users. In addition, the control architecture may
be scalable so that single sources can interoperate with multiple
devices, single devices can interoperate with multiple sources, and
so that both sources and devices may communicate with additional
processors that may or may not be directly integrated into the
wireless power charging system, and so on. The control architecture
may enable the wireless power systems to interact with larger
networks such as the internet, the power grid, and a variety of
other wireless and wired power systems.
[0010] An example that illustrates some of the advantages of the
distributed and segmented architecture we propose is as follows.
Imagine that an original equipment manufacturer (OEM) of an EV
wireless power transmission system may need to provide a system
with certain guaranteed and/or standardized performance such as
certain end-to-end transmission efficiency, certain tolerance to
system variations, certain guarantees for reliability and safety
and the like. An integrator who integrates the wireless power
transmission system into an electric vehicle may wish to
distinguish their vehicle by guaranteeing higher efficiency and/or
more robust safety features. If the control architecture is
structured in such a way that the integrator can set certain
thresholds in the control loops to ensure higher efficiency and/or
may add additional hardware (peripherals) to the system to augment
the existing safety features, then the integrator may be able to
offer significant product differentiation while also guaranteeing
that basic system requirements and/or standards are met. However,
if the control architecture is not segmented to offer some
reconfigurable functions while protecting the critical functions of
the wireless power system, changing certain control loops and/or
adding additional hardware may disrupt the required low-level power
delivery, reliability, and safety performance of the system.
[0011] Note that the inventive control architecture described in
this disclosure may be applied to wirelessly rechargeable electric
vehicles using traditional inductive and magnetic resonance
techniques. Because the performance of traditional inductive
wireless power transmission systems is limited compared to the
performance of magnetic resonance power transmission systems, the
exemplary and non-limiting embodiments described in this disclosure
will be for magnetic resonance systems. However, it should be
understood that where reference is made to source and device
resonators of magnetic resonance systems, those components may be
replaced by primary coils and secondary coils in traditional
inductive systems. It should also be understood that where an
exemplary embodiment may refer to components such as amplifiers,
rectifiers, power factor correctors and the like, it is to be
understood that those are broad descriptions and that amplifiers
may comprise additional circuitry for performing operations other
than amplification. By way of example but not limitation, an
amplifier may comprise current and/or voltage and/or impedance
sensing circuits, pulse-width modulation circuits, tuning circuits,
impedance matching circuits, temperature sensing circuits, input
power and output power control circuits and the like.
[0012] In one aspect of the invention a wireless energy transfer
system may include a segmented control architecture. The wireless
system may include a primary controller and a user configurable
secondary controller that is in communication with the primary
controller. The primary controller may be configured to perform the
essential control functions for the wireless system. The essential
control functions of the primary controller may include maintaining
the wireless energy transfer operating safety limits. The primary
controller may monitor and control the voltage and currents on the
components of the wireless energy transfer system. The user
configurable secondary controller may be configured to allow
adjustment of non-safety critical parameters of the system such as
adjusting the maximum power output, scheduling of on and off times,
adjusting the frequency of energy transfer, and the like. In
accordance with exemplary and non-limiting embodiments the primary
and secondary controllers may be implemented on separate hardware
or processors. In other exemplary embodiments the primary and
secondary controllers may be virtual controllers and implemented on
the same hardware.
BRIEF DESCRIPTION OF FIGURES
[0013] FIG. 1 shows exemplary components in an electric vehicle
wireless power transfer system.
[0014] FIG. 2 shows an exemplary charging system control diagram
for an electric vehicle wireless power transfer system. This
exemplary embodiment shows that system performance may be monitored
with a laptop through the wireless and/or wired "Debug" and
"Status" ports.
[0015] FIG. 3A shows a notional state diagram of the system
charging cycle. Activation states are denoted by the rectangles.
Conditional statements that enable transitions between states are
enclosed in square brackets. Fault detection on either side results
in both sides entering the Anomaly state.
[0016] FIG. 4 shows an exemplary charging cycle use-case.
[0017] FIG. 5 shows a Sequence Diagram for interaction between a
source and an electric vehicle during an exemplary charging
engagement.
[0018] FIG. 6 shows an exemplary embodiment of power factor
corrector control loops.
[0019] FIG. 7 shows an exemplary embodiment of source amplifier
control loops.
[0020] FIG. 8 shows an exemplary embodiment of device rectifier
control loops.
[0021] FIG. 9 shows exemplary interfaces to and from an application
source processor.
[0022] FIG. 10 shows exemplary interfaces to and from an
application device processor.
[0023] FIG. 11 shows exemplary interfaces to and from an amplifier
controller.
[0024] FIG. 12 shows exemplary interfaces to and from a recitfier
controller.
[0025] FIG. 13 shows exemplary ASP control parameters.
[0026] FIG. 14 shows exemplary ADP control parameters.
[0027] FIG. 15 shows exemplary amplifier control parameters.
[0028] FIG. 16 shows exemplary rectifier control parameters.
DETAILED DESCRIPTION
[0029] This disclosure describes exemplary reconfigurable system
control concepts for electric vehicle wireless power transmission
systems. In general, an electric vehicle (EV) may be any type of
vehicle such as a car, a boat, a plane, a bus, a scooter, a bike, a
cart, a moving platform, and the like that comprises a rechargeable
battery. The wireless power transmission system may provide power
to the battery charging circuit of the electric vehicle and/or it
may power the vehicle directly. Wireless power may be provided to
the vehicle while it is stationary or while it is moving. The power
provided wirelessly to recharge the vehicle battery may be more
than 10 Watts (W), more than 100 W, more than a kilowatt (kW), more
than 10 kW, and/or more than 100 kW, depending on the storage
capacity and power requirements of the vehicle. In some exemplary
low power embodiments, fewer control loops and/or less distributed
and/or less segmented control architectures may be sufficient to
ensure safe, reliable and efficient operation of the wireless power
transmission system. In some exemplary high power embodiments,
redundant control loops and/or multi-level control architectures
may be required to realize safe, reliable and efficient operation
of the wireless power transfer system.
[0030] This disclosure describes certain control tasks that may be
necessary for enabling an electric vehicle charging engagement
using a wireless energy transfer system as well as potential
control loops, states, and sequences of interactions that may
govern the performance of the system. The proposed control
architectures and tasks may enable transaction management (e.g.
billing, power origination identification, direction of power
flow), integration with vehicle electronics, and higher level
control tasks for system operation, communications, and anomaly
resolution. Throughout this disclosure we may refer to certain
parameters, signals, and elements as being variable, tunable,
controllable, and the like, and we may refer to said parameters,
signals and elements as being controlled. It should be understood
that system parameters, signals and elements may be controlled
using hardware control techniques, software control techniques,
and/or a combinations of hardware and software control techniques,
and that these techniques and the circuits and circuit elements
used to implement them may be referred to as controllers and/or
system controllers.
[0031] A block diagram of an exemplary wireless electric vehicle
(EV) battery charging system is shown in FIG. 1. In this exemplary
embodiment the system is partitioned into a source module and a
device module, with each module consisting of a resonator and
module control electronics. The source module may be part of a
charging station and the device module may be mounted onto a
vehicle. Power may be wirelessly transferred from the source to the
device via the resonators. Closed loop control of the transmitted
power may be performed through an out-of-band communications link
between the source and the device, an in-band communications link
between the source and the device, or a combination of in-band and
out-of-band signaling protocols between the source and device. In
some exemplary and non-limiting embodiments, some or all of the
system control functions may be realized in a computer, processor,
server, network node and the like, separated from the source and
device modules. In some exemplary embodiments, the system
controller may control more than one source, more than one device
and/or more than one system.
[0032] A wireless power transmission system for electric vehicle
charging can be designed so that it may support customization and
modifications of the control architecture. Such customizations and
modifications may be referred to as reconfigurations, and an
architecture designed to support such reconfigurations may be
referred to as reconfigurable. In some exemplary and non-limiting
embodiments, the control architecture may be realized in physically
separate components, such as multiple microprocessors and some
functions, processes, controls, and the like may be reconfigurable
by a user of the system, and some may not. In some exemplary and
non-limiting embodiments, the reconfigurable portions of the
control architecture may be implemented in certain chips,
micro-processors, field programmable gate arrays (FPGAs),
Peripheral Interface Controllers (PICs), Digital Signal Processors
(DSPs), Application Specific Processors (ASPs), and the like. In an
exemplary embodiment, some reconfigurable portions of the control
architecture may reside in ASPs which may be 32-bit
microcontrollers with C-language source code. In some exemplary and
non-limiting embodiments, the control code may reside on a single
processor and a user may have permission to access certain portions
of the code. In exemplary and non-limiting embodiments, both
hardware and software segmentation of the control functions of an
EV wireless power transmission system are contemplated in this
disclosure.
[0033] In an exemplary embodiment, the system architecture may
support ASPs in the source and device modules and these processors
may be referred to as Application Source Processors (ASP) and the
Application Device Processors (ADP). This control architecture may
enable different users and/or manufacturers of different vehicles
and vehicle systems to be able to add to the source code or
customize it for integration with their vehicles and/or in their
intended applications. Throughout this disclosure we may use the
terms processor, microprocessor, controller, and the like to refer
to the ASPs described above and any suitable type of
microprocessor, field programmable gate array (FPGA), Peripheral
Interface Controller (PIC), Digital Signal Processor (DSP), and the
like, that is known to one of skill in the art. In exemplary and
non-limiting embodiments, the ASP and ADP may be used to present
certain system parameters and control points to wireless power
system designers and/or vehicle integrators and to restrict access
to certain other system parameters and control points. For example,
certain control features may be essential to ensure proper and/or
safe operation of a wireless power transmission system, and such
control features may be implemented in hardware only loops and/or
in physically separated microcontrollers and/or in restricted
portions of the ASPs so that they may not be customized and/or
modified by certain users of the systems.
[0034] In exemplary and non-limiting embodiments, one, some or all
of the control functions of the wireless power system may be based
on hardware implementations and/or may be hard-coded into the
system and/or may be soft-coded into the system but with restricted
access so that only select and verified users may make changes to
the various codes, programs, algorithms and the like, that control
the system operation.
[0035] Note that whether or not the functionality associated with
the ASPs in this exemplary embodiment are realized in physically
separate hardware components or in isolated sections of code, the
concept of partitioning the control plane into at least source-side
and device-side functions and into at least high-level and
low-level functions is what enables the reconfigurability of system
operation while guaranteeing certain safety, reliability and
efficiency targets are met. The distribution and segmentation of
the control plane allows flexibility in the adaptation of the
higher level functions for vehicle designer and/or end user
applications without the risk of disrupting the operation of the
low level power electronics control functions. In addition, the
partitioning of the control plane allows for variable control loop
speeds; fast and medium speeds for the low level critical hardware
control functions of the power electronics as well as slower
control loop speeds for the high level designer and/or end user
control loops.
[0036] As time goes on, this partitioned control plan architecture
may scale to adjust to and support more functionality and
applications, at the same time it may be adapted to changing
hardware requirements and standardized requirements for the safe
and efficient delivery of power. For example, the fast and medium
speed control loops may be adapted to support wireless power
transmission at a range of operating frequencies and over a range
of coupling coefficients, both of which may eventually be set by
regulatory agencies. Also, users may access and customize the
higher level control functions to implement functionality that may
include, but may not be limited to: [0037] Programming an EV
wireless source to connect through a wired internet connection in
the source, or through Wi-Fi or the cellular network to display
certain source attributes such as what type of resonator it
comprises, how much energy it can supply, what the price is for the
energy it supplies (this price may change during the day, being
less expensive at night when the peak demand for electricity is
lower, or it may change seasonally, costing more when the
temperature is hot and air conditioning requirements are stressing
the electrical suppl), where the energy it supplies originates from
(renewables, coal plant, etc.), does this source require a
reservation, if it requires a reservation, when are the free times
that can be reserved, what type of FOD detectors does it deploy,
what is the status of the source (has FOD been detected and needs
to be cleaned off before charging can be initiated, or has FOD been
detected and so the source can only supply a limited amount of
power). [0038] Programming an EV wireless power transfer system so
that it may connect to a communication network and may contact the
vehicle user to report the status of the charge cycle and to report
when charging is complete or when charging has been interrupted or
that the source and/or device are in an anomaly state. [0039]
Programming an EV wireless power transfer system so that power is
transmitted from the device back to the grid and managing the
transaction so that the vehicle user is paid for supplying that
energy. [0040] Programming a user interface in the vehicle so that
information regarding the position of the vehicle resonator
relative to the source resonator can be relayed to the driver of
the vehicle. The relative position information may be used to give
the vehicle driver an estimate of the wireless transfer efficiency
with the vehicle in its current location and may offer the driver a
chance to change the parking position to improve the wireless
system performance. The user interface may include visible,
audible, vibrational and the like feedback to help the driver
reposition the vehicle. [0041] Programming an EV wireless power
transfer system so that it communicates with an automatic vehicle
parking capability resident on the vehicle and parks the vehicle in
a position that is optimized for wireless power transfer
efficiency. Other commands that may be communicated from the EV
wireless power transmission system to the vehicle may include
commands to control the active suspension of the vehicle to raise
or lower the vehicle relative to the source to optimize wireless
power transfer.
[0042] FIG. 2 shows an exemplary charging system control diagram
for an electric vehicle wireless power transfer system. In this
block diagram, the source components of the system are shown on the
left side of the diagram and the device (or vehicle) components of
the system are shown on the right.
[0043] In exemplary and non-limiting embodiments, AC line power may
flow into a power factor corrector (PFC) and provide a DC voltage
to a switching amplifier. In exemplary and non-limiting
embodiments, the DC voltage provided to the switching amplifier may
be variable and may be controlled. In exemplary and non-limiting
embodiments, a DC voltage may be provided to the amplifier from a
DC source of power (not shown) such as a solar cell, a battery, a
fuel cell, a power supply, a super capacitor, a fly wheel, and the
like. In exemplary and non-limiting embodiments, the DC voltage
from a DC power source may be variable and may be controlled.
[0044] The switching amplifier in the source of an electric vehicle
wireless power transmission system may be any class of switching
amplifier including, but not limited to, a class D amplifier, a
class E amplifier and a class D/E amplifier. The switching
frequency of the amplifier may be any frequency and may preferably
be a frequency previously identified as suitable for driving
inductor coils and/or magnetic resonators. In exemplary and
non-limiting embodiments, the switching frequency may be between 10
kHz and 50 MHz. In exemplary and non-limiting embodiments, the
frequency may be approximately 20 kHz, or approximately 44 kHz, or
approximately 85 kHz, or approximately 145 kHz, or approximately
250 kHz. In exemplary and non-limiting embodiments, the switching
frequency may be between 400 and 600 kHz, between 1 and 3 MHz,
between 6 and 7 MHz, and/or between 13 and 14 MHz. In exemplary and
non-limiting embodiments, the frequency of the switching amplifier
may be tunable and may be controlled.
[0045] In exemplary and non-limiting embodiments, an amplifier
controller may manage the electronic components in the amplifier
and/or in the PFC and/or in the DC power supply (not shown). The
amplifier controller may monitor and control so-called local
control loops and local interlocks for conditions such as over
voltage/current in the source electronics, ground-fault circuit
interrupt in the source electronics, and out-of-specification AC
impedance changes at the source coil. In exemplary and non-limiting
embodiments, the amplifier controller may react quickly to shut the
system down safely in response to a variety of set point
violations. The amplifier controller may expose registers for
set-points and control to the ASP through an inter-integrated
circuit (I.sup.2C) interface, referred to in the figure as the
"User Interface". The amplifier controller may also have a watchdog
timer (or heartbeat input) to detect if communication with the
Application Source Processor (ASP) or with the vehicle has been
lost.
[0046] In an exemplary embodiment, the ASP may provide high-level
control of the source electronics and the overall system charging
cycle. For example, the ASP may interface with a
foreign-object-debris (FOD) detector that monitors the source
module for the presence of FOD and/or excessive temperature. The
ASP may be connected to an in-band and/or out-of-band
communications link that may communicate with the vehicle-side
application device processor (ADP) to provide closed loop control
of the charging cycle.
[0047] In an exemplary embodiment on the vehicle side (also called
the device side), a rectifier controller may perform low-level and
local functions for the device side that are analogous to those
described for the source side. Again, an I.sup.2C interface may be
provided for interfacing with a higher-level ADP. The ADP could be
configured to connect via a CAN-bus or equivalent to a battery
manager that may control the power delivered from the rectifier to
the battery, vehicle engine or any time of power storage or
management system on the vehicle. The ADP could communicate that
information to the source-side ASP which, in turn, could adjust the
power settings on the amplifier controller.
[0048] In an exemplary embodiment, the control architecture may be
partitioned into three types of control loops: fast, medium and
slow. The fast control loops may be for time critical functions
(less than 1-ms latency) and may be either hardware control loops
or interrupt-driven low-level software modules. Medium-speed
control loops may be for functions that operate under real-time
software control (<500-ms latency). Slow control loops (>500
ms latency) may be for functions with low bandwidth requirements or
functions with unpredictable latency, for example, a 802.11-family
wireless communication link.
[0049] FIG. 2 shows the three types of control loops as they may be
applied to an exemplary electric vehicle wireless power
transmission system. In exemplary and non-limiting embodiments,
embedded software portions of the control loops may be partitioned
between the amplifier and rectifier controllers and the processors
(ASP and ADP). The amplifier and rectifier controllers may handle
the hardware control and the operation of high-power and/or
sensitive electronics components. The ASPs may handle the system
control loop and may provide interfaces to external peripherals,
such as FOD detectors, communication links, monitoring equipment,
and other vehicle and source electronics.
[0050] In exemplary and non-limiting embodiments, some of the
functions that may operate under fast feedback-loop control may be
based on hardware set-points and/or on software (programmable)
set-points which may include but may not be limited to over-current
protection, over-voltage protection, over-temperature protection,
voltage and current regulation, transistor shoot-through current in
the switching amplifier, GFCI (ground fault circuit interrupt) and
critical system interlocks. In exemplary and non-limiting
embodiments, system events that may cause damage to the system
itself or to a user of the system in a short period of time may be
detected and reacted to using fast feedback-loop control.
[0051] In exemplary and non-limiting embodiments, some of the
functions that may operate under medium-speed feedback loops may
include, but may not be limited to temperature set-point
violations, impedance set points to declare an out-of-range
condition for the source coil impedance, FOD detection, monitoring
for violations of the minimum efficiency set point, local power
control in the source-side electronics and processor heartbeat
monitoring (i.e. watchdog-timer expiration). In exemplary and
non-limiting embodiments, system events that may cause damage to
the system itself or to a user of the system in a medium period of
time and/or that may cause the system to operate in an undesirable
state (e.g. low efficiency) may be detected and reacted to using
medium feedback-loop control.
[0052] In exemplary and non-limiting embodiments, some of the
functions that may operate under relatively slow-speed loop control
may include but may not be limited to system power control loop
(e.g. for executing a battery-charging profile), charge
request/acknowledge messages between vehicle(s) and source(s),
system start/stop messages, system level interlocks, RF
communications link heartbeat monitoring (i.e. watchdog-timer
expiration), status/GUI updates to a diagnostic laptop and messages
for source/vehicle transactions, authentication and configuration.
In exemplary and non-limiting embodiments, system events that may
cause damage to the system itself or to a user of the system in a
long period of time and/or that may cause the system to operate in
an undesirable state (e.g. low efficiency, insufficient information
for closing a transaction) may be detected and reacted to using
slow feedback-loop control.
[0053] FIG. 3 shows a notional state diagram of the system charging
cycle. The diagram shows examples of state machines that may be
running on the ASPs in the source side and the vehicle side of the
EV wireless power transmission system. Potential activation states
are shown within each rectangle and potential conditional
statements that must be satisfied to enable transitions between
states are enclosed in square brackets. In exemplary and
non-limiting embodiments, in-band, out-of-band, and/or a
combination of in-band and out-of-band wireless communication links
between the source and the vehicle may provide for messaging and
synchronization. In exemplary and non-limiting embodiments, the
communications required to implement control functions, processes
and the like may piggy-back on existing or native communication
systems in and around the vehicle. For example, messages may be
passed amongst the source(s), the vehicle(s), and any additional
networked component(s) using CAN-bus equipment and protocols,
Bluetooth equipment and protocols, Zigbee equipment and protocols,
2.4 GHz radio equipment and protocols, 802.11 equipment and
protocols, and/or any proprietary signaling scheme equipment and
protocols implemented by the user.
[0054] For charging electric vehicles that may be described in the
standards proposed by the Society of Automotive Engineers (SAE),
the charging engagement between the source and vehicle for wireless
charging may be similar to that described by SAE J1772 for wired
charging, with additional steps added to support wireless
charging.
[0055] An exemplary use-case for stationary EV charging involving
the operation of the control system is shown in the table in FIG.
4. In an exemplary embodiment, a wireless source may be powered and
available to supply power to a wireless device and may be referred
to as being in the Available state. A wireless source may
constantly, periodically, occasionally and/or in response to some
trigger, broadcast information regarding any of its availability,
position, location, power supply capabilities, power costs, power
origination (solar, coal burning plant, renewable, fossil fuel,
etc.), resonator type, resonator cross-section (so that a vehicle
may calculate and/or look-up an expected coupling coefficient with
the source), and the like. A vehicle may be receiving information
broadcast by wireless power sources and may search for an available
wireless power source, with matching hard-wired and/or use
selectable features, over which it may park. The vehicle's
communication link may be active so that it is in the Searching
state. If vehicle identifies a suitable wireless source, it may
approach that source and initiate two way communications with the
source so that the source and device side control electronics can
exchange configuration information. In an exemplary embodiment,
when sufficient information has been exchanged by the source and
the device, and when the vehicle resonator has been positioned
substantially in the near vicinity of the source resonator, the
source and vehicle sides may switch to their Docking states.
[0056] In an exemplary Docking state, both source and device may
confirm their compatibility and an alignment error signal may be
provided to the vehicle driver so that he/she can maneuver the car
into proper position. Once in position, the drive train of the
vehicle may be disabled and the source and device may enter the
Coupled state.
[0057] In an exemplary embodiment, a `Charge Request` may be sent
from the vehicle--either automatically or driver initiated, and may
be received by the source. In the Coupled state, there may be
further exchange of configuration information, safety checks, and
the like. Once those are passed, both sides may enter the Ready to
Charge state.
[0058] In an exemplary embodiment, in the Ready to Charge state,
the vehicle may issue a `Start Charging` command and both the
source and the vehicle may enter the Charging state as the source
power ramps up. In the Charging state, both source and vehicle may
perform monitoring and logging of data, faults, and other
diagnostics. Logging and monitoring may include, but may not be
limited to an event loop that looks for hazardous and/or restricted
Foreign Object Debris (FOD), overloads, unexpected temperature
and/or efficiency excursions, and other asynchronous events.
[0059] In exemplary and non-limiting embodiments, hazard and/or
restricted object detection that occurs in the source during any of
the powered states may cause the source to switch into its Anomaly
state. If wireless communication is still working, the vehicle may
be notified and may also drop into its Anomaly state. If wireless
communication is down, the vehicle may enter its Anomaly state
because it didn't ask for the wireless power to be shut down and
because the wireless communications watchdog timer expires.
[0060] In an exemplary embodiment, where the vehicle has entered
the Anomaly state, state, the vehicle may send a message to the
source that results in the source entering its Anomaly state.
[0061] In an exemplary embodiment, where the source has entered the
Anomaly state, the source may send a message to the vehicle that
results in the vehicle entering its Anomaly state.
[0062] In an exemplary embodiment, the source and/or vehicle may
automatically begin a process for handling or disposition of the
anomaly. The process may involve the source and vehicle exchanging
health and status information to help discover the cause of the
anomaly. Once the cause is determined, the source and vehicle may
select a pre-planned action that corresponds to the cause. For
example, in the event that detection of foreign object debris
caused the anomaly, the source may reduce the power transfer level
to a safe level where the foreign object debris does not overheat.
In another example, in the event that the loss of RF communication
was the cause, the source may stop power transfer until RF
communication is re-established. In exemplary and non-limiting
embodiments, where one or both sides of the system may have entered
the anomaly state, the system may automatically communicate to a
user that the system is in its Anomaly state. Communication may
occur over the internet, over a wireless network, or over another
communications link.
[0063] In an exemplary embodiment, under normal operating
conditions, charging may end when the vehicle sends a stop-charging
(DONE) command to the source. The source may immediately
de-energize.
[0064] In this exemplary embodiment, after de-energizing, the
source may return to the coupled state and may notify the vehicle
of its state change. The vehicle may switch to the Coupled state
and may receive additional information about the charge engagement
from the source. At this point, the vehicle may either stay put or
it may depart. Once the source senses that a vehicle has departed,
it may return to the Available state.
[0065] Not explicitly shown the figures are exemplary control loops
that may perform system safety and hazard monitoring, as well as
localized FOD detection, for example. There a many ways a FOD
detector might be used including; prior to a source declaring
itself Available, it may run through a series of diagnostic tests
including FOD detection, in the Docking and in the Coupled states,
the FOD detector could check for potentially hazardous debris
falling off of a vehicle and onto a source resonator, and before
entering the Ready to Charge state, a FOD detector reading may be
part of a final safety check. In exemplary and non-limiting
embodiments, monitoring for FOD may occur during the Charging
state. In exemplary and non-limiting embodiments, one, some or any
anomalies or failed safety checks may turn down or shut down the
amplifier and put both sides (source and vehicle) into their
Anomaly states, where additional diagnostics can be safely
performed.
[0066] FIG. 5 shows another representation of some potential steps
if a sequence of interactions in an exemplary embodiment of an EV
wireless power transfer system. The diagram shows exemplary steps
from the charging sequence described above following Unified
Modeling Language (UML) conventions: [0067] Time flows in the
downward direction [0068] The vertical bars under each side
represent activation of different states [0069] Arrows with solid
lines indicate requests [0070] Arrows with dashed lines indicate
responses [0071] Full arrow heads represent synchronous messages
[0072] Half arrow heads represent asynchronous messages [0073]
Arrows entering the diagram from off the page represent user
actions Note that the diagram is not intended to show every message
in the exemplary engagement just some examples helpful to
understanding the interaction.
[0074] In exemplary embodiments of electric vehicle wireless power
systems, a variety of control loops may be implemented to govern
the operation of the wireless charging and/or powering of the
electric vehicle. Some exemplary control loops for the exemplary
system shown in FIG. 2 are described below. The control loops
described below may be sufficient for some systems or they may need
to be modified or added to ensure proper operation of other
systems. The description of control loops should not be interpreted
as complete, but rather illustrative, to describe some of the
issues considered when deciding whether system control loops might
be fast, medium or slow in their response time, and whether or not
they should be user reconfigurable.
[0075] In an exemplary EV wireless power transfer system, a power
factor corrector may convert an AC line voltage to a DC voltage for
the source. It may provide active power factor correction to the
line side and may provide a fixed or variable DC voltage to the
source amplifier. Control of a power factor corrector may be
performed through a combination of hardware circuits and firmware
in the amplifier controller. For example hardware circuits may be
used to control against transient or short-duration anomalies, e.g.
exceeding hard set-point limits such as local currents or voltages
exceeding safety limits for circuit components, such as power
MOSFETs, IGBTs, BJTs, diodes, capacitors, inductors, and resistors,
and firmware in the amplifier controller may be used to control
against longer duration and slower developing anomalies, e.g.
temperature warning limits, loss of synchronization of switching
circuitry with the line voltage, and other system parameters that
may affect power factor controller operation.
[0076] In this exemplary embodiment, an amplifier may provide the
oscillating electrical drive to the wireless power system source
resonator. Hardware circuits may provide high-speed fault
monitoring and processing. For example, violations of current and
voltage set points and amplifier half-bridge (H-bridge)
shoot-through may need to be detected within less than one
millisecond in order to prevent catastrophic failures of the source
electronics.
[0077] On a medium timescale, the amplifier controller may monitor
the impedance of the source coil and may react to out-of-range
impedance conditions in less than 500 ms. For example, if the
impedance is too inductive and out-of-range, the efficiency of
power transfer may be reduced and the system may turn down or shut
down to prevent components from heating up and/or to prevent
inefficient energy transfer. If the impedance is inductive, but low
and out of range, the system may react as when the resonator is too
inductive, or it may react differently, or more quickly, since
transitioning from an inductive load to a capacitive load may
damage the source electronics. In exemplary and non-limiting
embodiments, a hardware circuit may be used to sense if the load
the amplifier is driving has become capacitive and may over-ride
other slowed control loops and turn down or shut down the source to
prevent the unit from becoming damaged.
[0078] In exemplary and non-limiting embodiments, system-level
power requirements may be determined on the vehicle side and may be
fed back from the ADP to the ASP. Over I2C, the ASP may request
that the amplifier controller increment or decrement the power from
the amplifier for example. The bandwidth of the power control loop
may be limited by the latency in the wireless link and by the
latency in communication between the ADP and the battery
manager.
[0079] In exemplary and non-limiting embodiments, a rectifier may
convert the AC power received from the device resonator to DC
output power for the vehicle, vehicle battery or battery charger. A
monitoring circuit for the rectifier output power, current and or
voltage, as well as for the battery charge state may provide the
feedback for closed-loop control of the system's power transfer.
The rectifier may control the output voltage to maintain it within
the range desired by the battery management system. Additional
fault monitoring and an interface to vehicle charging control
processes may be provided by the ADP.
[0080] In an exemplary embodiment, a rectifier module may comprise
a full-bridge diode rectifier, a solid-state switch (e.g. double
pole, single throw (DPST) switch), and a clamp circuit for
over-voltage protection. Under normal operation, the full-bridge
rectifier may send DC power through the closed switch and the
inactive clamp circuit to the battery system. If the battery system
needs more current, it may request it from the ADP which may
forward the request to the ASP on the source side. If the battery
needs less current, the corresponding request may be made. The
speed with which these conditions must be detected, communicated,
and acted upon may be determined by how long the system can safely
operate in a non-ideal mode. For example, it may be fine for the
system to operate in a mode where the wireless power system is
providing too little power to the vehicle battery, but it may be
potentially hazardous to supply too much power. The excess power
supplied by the wireless source may heat components in the
resonator, clamp circuit and/or battery charge circuit. The speed
of the feedback control loop may need to be fast enough to prevent
damage to these components but may not need to be faster than that
if a faster control loop is more expensive, more complex, and/or
less desirable for any reason.
[0081] In exemplary and non-limiting embodiments, a switch and a
clamp may provide vehicle-side protection against potential failure
modes. For example, if the vehicle side enters its Anomaly state,
it may notify the source which may subsequently enter its Anomaly
state and may turn down or shut down the source power. In case the
wireless link is down or the source is unresponsive, the switch in
the rectifier may open to protect the battery system.
[0082] In an exemplary embodiment, an ADP could enter its Anomaly
state in several ways. A few examples include: [0083] The battery
manager requests an emergency disconnect [0084] The voltage clamp
circuit is active for more than 3 seconds (or some set period of
time, potentially user settable and reconfigurable) [0085] The
wireless communications link is down [0086] The ADP does not update
the watchdog timer in the rectifier controller [0087] A
temperature, voltage, current, or other error-condition set point
is violated.
[0088] In an exemplary and non-limiting embodiment of a charging
engagement, control-system information may flow across the
following interfaces: [0089] ASP-ADP: Wireless interface between
the Application Source Processor on the source side and the
Application Device Processor on the vehicle side. [0090]
ASP-Laptop: Wireless interface used to send a webpage with source
diagnostic information that can be displayed on a laptop for
demonstration, system configuration, and debug purposes. [0091]
ADP-Laptop: Wireless interface used to serve a webpage with device
diagnostic information that can be displayed on a laptop for
demonstration and debug purposes. [0092] ASP-AmpCon: an I2C
interface between the ASP and the amplifier controller. [0093]
ADP-RectCon: an I2C interface between the ADP and the rectifier
controller.
[0094] In exemplary and non-limiting embodiments, the first
interface (ASP-ADP) may be used to exchange the messages needed to
support the exemplary Sequence Diagram shown in FIG. 5. It may be
that standardization activities will specify certain wireless
communications protocols, such as the IEEE 802.11p protocol and/or
Dedicated Short Range Communications (DSRC) using a licensed band
at 5.9 GHz. In exemplary and non-limiting embodiments that comply
with standards, it may be that only certain wireless communications
protocols will be supported by and used to implement the wireless
power system controls. In exemplary and non-limiting embodiments
not governed by standards, both known and proprietary wireless
communications protocols may be supported by and used to implement
wireless power system controls. In an exemplary embodiment, a
reconfigurable EV wireless power transfer system has been
demonstrated using the IEEE 802.11b unlicensed band (Wi-Fi) to
implement the system control commands and communication.
[0095] In exemplary and non-limiting embodiments, the second and
third diagnostic interfaces may be for running demonstration
purposes and to provide diagnostic information in an easily
accessible format. The connections with the laptop may also use
802.11b. A Wi-Fi enabled router may be required for simultaneous
support of wireless connections for the ASP-ADP, ASP-Laptop, and
ADP-Laptop. For demonstrations that only require the ASP-ADP
connection, an 802.11b peer-to-peer connection could be used.
[0096] In exemplary and non-limiting embodiments, the fourth and
fifth interfaces may be between the ASPs, other system controllers,
and data loggers. Other system controllers may be implemented in
physically distinct microcontrollers as described in the exemplary
embodiment, or they may be co-located in the same ASPs.
[0097] Some example interactions amongst the ASP, ADP, controllers
and FOD detectors are described below. These are just some of the
example interactions, but in no way are the interactions
contemplated by this invention limited to only the examples given
below.
[0098] In an exemplary embodiment, an Application Source Processor
(ASP) may be a microprocessor that holds the state information for
the source side of the reconfigurable EV wireless power transfer
system. Physically, it may be implemented in a PIC-32
microcontroller. The software running on the ASP may execute the
state transitions described previously, as well as the wireless
communication with the vehicle side and potentially with the
diagnostic laptop (if present). It is anticipated that users may
modify or replace the software on the ASP and still operate the
reconfigurable EV wireless power transfer system. Functional
interfaces to the Application Source Processor may include, but may
not be limited to: [0099] Wi-Fi link for communicating with the
vehicle's ADP and for a diagnostic display for user demonstrations,
diagnostics and/or customization (iPAD or laptop) [0100] Serial
Peripheral Interface (SPI) serial-link over Ethernet on a 2.4 GHz
RF link for communicating with the vehicle's ADP [0101] Hardware
support for Universal Asynchronous Receiver/Transmitter (UART)
serial-link over Ethernet on a 2.4 GHz RF link for an alternative
method of communicating with the vehicle's ADP [0102] Interface to
amplifier controller [0103] I.sup.2C for commanding and receiving
status information [0104] Interrupt for high-priority tasks (e.g.
FOD detection, source or vehicle anomaly) [0105] Bi-directional
watchdog/heartbeat signal [0106] FOD detection interface [0107]
Metal object detector [0108] Temperature sensors [0109] Living
being sensor [0110] System process interlock inputs-used for
higher-level controllers that may need to shut down the source
suddenly. [0111] I.sup.2C interface to source side PIM (PCB
Information Memory with a unique identifier (UID), configuration
settings, etc.)
[0112] In an exemplary embodiment, an ASP may have a Wireless
Communications Link Interface. For example, the source-side ASP may
communicate with the vehicle-side ADP over a wireless communication
link. The wireless protocol may be implemented using TCP/IP over a
2.4 GHz Wi-Fi link. The RF module may be IEEE Std. 802.11b
compatible with a 4-wire SPI interface to the ASP.
[0113] In an alternate exemplary embodiment, a communication
interface using the ASP serial UART port may be available as an
option. The serial port might interface to an external wireless
module to support the link. A standard UART interface may provide
the flexibility to use any particular wireless protocol that a user
may want.
[0114] In an exemplary embodiment, there may be an interface
between the ASP and the amplifier controller. An amplifier
controller may provide low-level control of the source electronics,
while the ASP may provide high-level control and may be responsible
for the execution of the overall system charging cycle. The
interface to the amplifier controller may be presented as a set of
control and status registers which may be accessible through an
I.sup.2C serial bus. Such an arrangement could support user
customization of the control algorithms.
[0115] In an exemplary embodiment, there may be an interface
between an ASP and a FOD detection subsystem. The ASP may be able
to receive preprocessed digital data from a FOD processor. A FOD
processor may be designed to perform signal conditioning and
threshold detection for the various types of sensors connected to
it. Upon detection of FOD, the FOD processor may interrupt the ASP
and transmit the FOD decision-circuit results. The ASP may then
take appropriate action (e.g. shut down the power, go to a
low-power state, issue a warning, etc.) The FOD processor may also
transmit the pre-decision signal-conditioned data in digital form
to the ASP so that soft decision algorithms that use other
information can be implemented in the ASP.
[0116] In an exemplary embodiment, there may be an interface
between an ASP and a System Interlock subsystem. An interlock
interface may consist of a set of optically coupled digital inputs
which may act as system enables. The interlocks may be externally
generated signals which may be asserted to turn on the system. The
interlocks may also be able to be used by the user to shut down the
system on command. The systems and signals that feed the external
interlock signals (shutdown switch, additional FOD detection,
infrastructure fault detection, etc.) may be application
specific.
[0117] In an exemplary embodiment, there may be an interface
between an ASP and a Positioning and Alignment Interface. A
positioning and alignment interface may communicate data from a
vehicle alignment and positioning sensor to an ASP to determine
whether sufficient wireless power transfer efficiency may be
achieved given the measured relative position of source and device
resonators. If the resonators are not sufficiently well aligned,
the ASP may communicate to the device ADP and instruct the system
to generate a message to the driver that the vehicle needs to be
repositioned and to inhibit system turn-on until proper positioning
is established.
[0118] In exemplary and non-limiting embodiments, there may be an
interface between an ASP and a Diagnostic/Debug subsystem. For the
purposes of demonstrations, customization, and testing, a
diagnostic/debug interface may be available across a wireless link
between an ASP and a laptop, or tablet, or smartphone or any other
processing unit that preferably comprises a display. In some
exemplary and non-limiting embodiments, the wireless communications
connection may be through a dedicated Wi-Fi network. In exemplary
and non-limiting embodiments, the interface may allow a laptop, or
other external controller, to put the EV wireless power
transmission system in a diagnostic and/or customization mode where
preset interlocks may be over-ridden and state changes may be
forced onto the ASP.
[0119] In exemplary and non-limiting embodiments, this interface
may also allow a laptop, or other external controller, with a Wi-Fi
capability to access the ASP. For example, the ASP may be capable
of streaming state information to the laptop which may store it in
a log file. Parameters that can be stored in the log file may
include: [0120] Time-stamped events such as state changes, messages
passed, messages received [0121] Measured voltages, currents,
temperatures, and impedances that are being compared to set points
by the ASP or amplifier controller. [0122] Configuration
information such as software/firmware versions, hardware IDs, etc.
[0123] The log file should be able to be viewed on the laptop and
incorporated into a spreadsheet for later analysis.
[0124] In exemplary and non-limiting embodiments, an Application
Device Processor (ADP) may be a microprocessor that holds the state
information for the vehicle side of an EV wireless power transfer
system. Physically, it may be implemented in a PIC-32
microcontroller. In exemplary and non-limiting embodiments, the
software running on the ADP may execute the state transitions
described previously, as well as the wireless communication with
the source side and the diagnostic laptop, or other external
controller. Users may modify or replace the software on the ADP to
customize the operation and control of an EV wireless power
transfer system.
[0125] In exemplary and non-limiting embodiments, functional
interfaces to the Application Device Processor may include but may
not be limited to: [0126] Controller Area Network (CAN) Bus
implemented on the physical layer (PHY) on the device side for use
with vehicle communication, diagnostic equipment, and/or
measurement and or monitoring equipment [0127] Serial-link over
Ethernet on a 2.4 GHz RF link for communicating with the Source ASP
[0128] Wi-Fi to a diagnostic display for user demonstrations and/or
customizations (iPAD or laptop) [0129] Interface to a rectifier
controller [0130] I.sup.2C for commanding and receiving status
information [0131] Interrupt for high-priority tasks (e.g. FOD
detection, vehicle anomaly) [0132] Bi-directional
watchdog/heartbeat signal [0133] System process interlock inputs
used for higher-level controllers on a vehicle that may need to
disable the charging cycle. [0134] I.sup.2C interface to Device
side PIM (PCB Information Memory with UID, configuration settings,
etc.)
[0135] In some exemplary and non-limiting embodiments, there may be
an interface between an ADP and a CAN Bus. In some exemplary and
non-limiting embodiments, the ADP may include a CAN bus interface.
In exemplary and non-limiting embodiments, software running on an
ADP may be augmented by a user to support a CAN bus interface even
if the as-designed and/or as-delivered EV wireless power transfer
system did not include this functionality.
[0136] In exemplary and non-limiting embodiments, a vehicle-side
Application Device Processor may have a Wireless Communications
Link Interface. For example, a device-side ADP may communicate with
the source-side ASP over a wireless communication link. The
wireless protocol may be implemented using TCP/IP over a 2.4 GHz
Wi-Fi link. The RF module may be IEEE Std. 802.11b compatible with
a 4-wire SPI interface to the ADP.
[0137] In exemplary and non-limiting embodiments, there may be an
interface between an ADP and a rectifier controller. The ADP may
communicate with the rectifier controller over an interface that
may be similar to the one between the ASP and the amplifier
controller. A rectifier controller may provide low-level control of
the device electronics, while the ADP may provide high-level
control and may be responsible for the execution of the overall
system charging cycle. The interface to the rectifier controller
may be presented as a set of control and status registers which may
be accessible through an I.sup.2C serial bus. Such an arrangement
could support user customization of the control algorithms. The
interface may also consist of, an Interrupt Request input and a set
of uni-directional watchdog/heartbeat outputs.
[0138] In an exemplary embodiment, there may be an interface
between an ADP and a Positioning and Alignment Interface. A
positioning and alignment interface may communicate data from a
vehicle alignment and positioning sensor to an ADP to determine
whether sufficient wireless power transfer efficiency may be
achieved given the measured relative position of source and device
resonators. If the resonators are not sufficiently well aligned,
the ADP may communicate to the source ASP and instruct the system
to generate a message to the driver that the vehicle needs to be
repositioned and to inhibit system turn-on until proper positioning
is established.
[0139] In exemplary and non-limiting embodiments, there may be an
interface between an ADP and a System Interlock subsystem. This
interface may be analogous to that described between an ASP and a
System Interlock subsystem. It could be used by the battery manager
to force a shutdown of the EV wireless power transfer system. For
example, if the interlock is de-asserted, the ADP may enter its
Anomaly state and may demand that the source shut down immediately
and may open the switch in the rectifier circuit. In the case of an
unresponsive source or an interrupted wireless communications link,
the ADP may open the switch within 3 seconds, or an appropriate
period of time, and communicating a command that the source shut
down.
[0140] In exemplary and non-limiting embodiments, there may be an
interface between an ADP and a Diagnostic/Debug subsystem. For the
purposes of demonstrations, customization, and testing, a
diagnostic/debug interface may be available across a wireless link
between an ADP and a laptop, or tablet, or smartphone or any other
processing unit that preferably comprises a display. In some
exemplary and non-limiting embodiments, the wireless communications
connection may be through a dedicated Wi-Fi network. In exemplary
and non-limiting embodiments, the interface may allow a laptop, or
other external controller, to put the EV wireless power
transmission system in a diagnostic and/or customization mode where
preset interlocks may be over-ridden and state changes may be
forced onto the ADP.
[0141] In exemplary and non-limiting embodiments, this interface
may also allow a laptop, or other external controller, with a Wi-Fi
capability to access the ASP. For example, the ASP may be capable
of streaming state information to the laptop which may store it in
a log file. Parameters that can be stored in the log file may
include: [0142] Time-stamped events such as state changes, messages
passed, messages received [0143] Measured voltages, currents,
temperatures, and impedances that are being compared to set points
by the ADP or rectifier controller. [0144] Configuration
information such as software/firmware versions, hardware IDs, etc.
[0145] The log file could be viewed on the laptop and dumped into
excel for later analysis.
[0146] In exemplary and non-limiting embodiments of EV wireless
power transfer systems, an amplifier controller may provide
low-level control to a Power Factor Corrector (PFC) and a switching
amplifier. The interfaces between an amplifier controller and other
system components may include, but may not be limited to: [0147]
Interface to Application Source Processor [0148] I.sup.2C [0149]
Interrupt [0150] Bi-directional Heartbeat/Watchdog [0151] PFC
Hardware control interface [0152] Amplifier hardware control
interface [0153] System critical interlock inputs [0154] System
On/Off
[0155] In exemplary and non-limiting embodiments of EV wireless
power transfer systems, a rectifier controller may provide high
speed monitoring of rectifier power and system critical fault
control. The interfaces between a rectifier controller and other
system components may include, but may not be limited to: [0156]
I.sup.2C interface to Application Device Processor [0157] I2C
[0158] Interrupt [0159] Bi-directional Heartbeat/Watchdog [0160]
Rectifier hardware control/status interface [0161] Fault indicators
such as over current, over voltage, over temperature, clamp circuit
activated, etc. [0162] Device side system critical interlock
inputs.
[0163] An reconfigurable EV wireless power transmission system may
be partitioned into notional subsystems so that the interactions
between subsystems may be studied and design decisions made be made
as to which control functions and set-points may be customizable by
a use while still ensuring safe, efficient and reliable performance
of the system. One method to analyze the system performance impact
of allowing customization and/or reconfigurability of the control
architecture and/or algorithms and/or set-points is to perform a
Failure Mode Effects Analysis (FMEA). A preliminary FMEA may
comprise a prioritized listing of the known potential failure
modes. FMEA may need to be an on-going activity as new system
failure modes are identified.
[0164] In exemplary and non-limiting embodiments, an FMEA process
that scores potential failure modes in a number of categories may
be used to identify the severity of certain failure scenarios.
Categories that may be used to identify customizable parameters may
include, but may not be limited to [0165] Severity (1-10): If the
failure mode occurs, how severe (SEV) is the impact to system
functionality, performance, or safety? A score of 10 indicates a
major hazard and a score of 1 indicates a minor loss of performance
or functionality. [0166] Likelihood (1-10): How likely is the
failure to occur? A 10 indicates almost certain occurrence while a
1 indicates a very remote chance of occurrence (OCC). [0167]
Undetectability (1-10): How likely is it that the failure will be
detected (DET) and reacted to by the system during operation? A 10
indicates that the control architecture is very unlikely to detect
the failure while a 1 indicates almost certain detection.
[0168] In exemplary and non-limiting embodiments, the potential
failure modes may be prioritized according to their Risk Priority
Number (RPN)--which is merely the product of their three category
scores.
[0169] While the invention has been described in connection with
certain preferred exemplary and non-limiting embodiments, other
exemplary and non-limiting embodiments will be understood by one of
ordinary skill in the art and are intended to fall within the scope
of this disclosure, which is to be interpreted in the broadest
sense allowable by law. For example, designs, methods,
configurations of components, etc. related to transmitting wireless
power have been described above along with various specific
applications and examples thereof. Those skilled in the art will
appreciate where the designs, components, configurations or
components described herein can be used in combination, or
interchangeably, and that the above description does not limit such
interchangeability or combination of components to only that which
is described herein.
[0170] All documents referenced herein are hereby incorporated by
reference.
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