Patent Publication Number: US-2012025759-A1

Title: Electric Charger for Vehicle

Description:
BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to a charger for an electric vehicle, and in particular to an electric vehicle charger having at least a pair of inputs for receiving electrical power from multiple electrical circuits. 
     All-electric and hybrid-electric vehicles store electrical power in a storage device, such as a battery for example. The electrical power is then drawn upon by the vehicle to be converted into useful work, such as by powering motors that are connected to the vehicles wheels. In some vehicles, such as hybrid-electric vehicles for example, the energy stored in the battery is generated by a gasoline fueled engine. The engine rotates an electrical generator that produces electrical power. The electrical power may also be generated using other means such as regenerative braking, which converts the energy dissipated during the braking and slowing down of the vehicle into electrical energy for example. 
     The all-electric vehicle, which lacks an independently fueled engine, relies on an external power source to provide the energy stored in the battery. The all-electric vehicle includes a receptacle that allows the operator to couple the vehicle to a utility-grid connected electrical circuit. Electrical power is transferred from the grid connected electrical circuit to the vehicle for recharging the batteries. Some all-electric vehicles may also incorporate regenerative braking features as well. A third type of vehicle, the plug-in hybrid electric (“PHEV”) includes an engine for generating power during operation, but also incorporates a receptacle to allow the operator to recharge the battery when the vehicle is not in use. It should be appreciated that the cost of purchasing electrical power from an electrical utility is often more cost effective than combusting the equivalent amount of gasoline in an engine. 
     In an effort to promote standardization and interoperability, standards have been proposed, such as the J1772 standard promoted by the Society of Automotive Engineers (SAE) for example, that establish defined receptacle parameters and protocols. The J1772 standard provides three different levels of charging. The charging level depends on the capability of the vehicle to receive electrical power and the ability of the electrical circuit to deliver the power. 
     Level 1 charging allows the vehicle to receive electrical power from a 110 volt, 15-ampere circuit, such as that found in a common residential circuit. Level 1 charging provides an advantage in allowing the operator to connect in many locations using standard circuits, such as those commonly found in a residential garage. However, due to the low power capacity of these electrical circuits, an electric vehicle requires 24-26 hours to fully charge. A Level 2 designated charge allows the vehicle to receive electrical power from a 220V, 30 ampere circuit for example. The Level 2 charge will typically recharge a vehicle battery in three to six hours. These 220V circuits are found in some residences and may be used for certain existing appliances, such as a clothes dryer for example. While 220V circuits may be available at a residence, they are not commonly found in areas where the operator stores vehicles, such as a garage for example. Therefore, in order for an electric-vehicle operator to use a Level 2 charge, the operator may typically need to incur the additional expense of hiring an electrician to install the additional higher capacity circuits. It should be appreciated that in some circumstances the electrical circuits of the residence or facility may not support Level 2 charging and the operator will be limited to a Level 1 rate of charge. 
     A third charging protocol, known as a Level 3 charge, provides for charging the vehicle using a 440V circuit. The charging of the vehicle on a Level 3 circuit allows the charging of the vehicle battery in two to three hours. Residences with circuits capable of Level 3 charging are not yet common and are typically only available at commercial establishments. 
     It should be appreciated that a 24-26 hour recharge cycle provided by a Level 1 protocol may be too long to allow daily use of the vehicle. Further, it should be appreciated that if an operator purchases an electrically powered vehicle they may need to either wait for delivery until an electrician installs the Level 2 circuits, or greatly curtail usage of the vehicle until the desired circuits are installed. Since most purchasers of new vehicles find it desirable to utilize their vehicle immediately, these additional steps may curtail or inhibit greater acceptance of electrically powered vehicles. 
     Accordingly, while existing systems and methods for charging electrically powered vehicles are suitable for their intended purposes, a need for improvements remains in the decreasing of battery charge times without requiring the installation of new or additional higher capacity electrical circuits. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, an electric vehicle charger is provided. The electric vehicle charger includes a first electrical input, the first electrical input adapted to receive a first electrical power having a first voltage level and a first current level. A second electrical input is provided that is adapted to receive the first electrical power. A toroidal transformer is electrically coupled to the first electrical input and the second electrical input, the toroidal transformer having a first output, wherein the toroidal transformer is adapted to provide a second electrical power having a second voltage level and a second current level to the first output. A second output is configured to electrically couple between a vehicle and the first output. 
     According to another aspect of the invention, a device for charging a vehicle at a facility having a first electrical circuit and a second electrical circuit is provided. The device includes a first input electrically coupled to the first electrical circuit. A second input is electrically coupled to the second electrical circuit. A transformer is electrically coupled to the first input and the second input, the transformer being configured to combine an electrical power received from the first input and the second input. An output is electrically coupled to the transformer. 
     According to yet another aspect of the invention, a method of providing an electrical charge to a vehicle is provided. The method includes providing a transformer having an input portion and an output portion. The input portion is electrically coupled to a first input conductor and a second input conductor. The first input conductor is connected to a first electrical circuit and the second input conductor to a second electrical circuit. The output portion is electrically to the vehicle. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic view illustration of an electric vehicle charger in accordance with an embodiment of the invention; 
         FIG. 2  is schematic diagram illustrating an electric circuit for the electric vehicle charger of  FIG. 1 ; 
         FIG. 3  is a schematic view illustration an electric vehicle charger in accordance with another embodiment of the invention; 
         FIG. 4  is a schematic illustration of a utility electrical distribution system; 
         FIG. 5  is a schematic illustration of a vehicle charging system in accordance with an embodiment of the invention; and, 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Vehicles that utilize electrical power as a primary energy source typically have a receptacle that allows the vehicle receive electrical power from an external source. The received electrical power is stored in a battery for later use when the vehicle is operated. Typically, the vehicle will have onboard circuitry that controls the flow of electrical power and adapts the electrical characteristics of the electrical power to those desired by the vehicle. Many commercially available electrically powered vehicles comply with Level 1 (110V) and Level 2 (220V) protocols of the Society of Automotive Engineers (“SAE”) standard J1772. The SAE J1772 standard also provides for a third rate of charge known as Level 3 (440V). The charging capacity of the external source is often the limiting factor that determines the rate at which the vehicle&#39;s battery will charge. 
     An exemplary embodiment of an electric vehicle charger  20  is illustrated in  FIG. 1 . The charger includes a housing  22  having a plurality of inputs  24 . Each of the plurality of inputs  24  is connected to a conductor  30  having a plug  32  sized to connect with a standard electrical output, such as a National Electric Manufacturers Association (NEMA) 5-15 or a NEMA 6-30 compliant outlet for example. In one embodiment, the conductors  30  are removably connected to the plurality of inputs  24 , such that the conductors  30  may be exchanged with connectors having different plug types. The housing  22  further includes an output  26 . In the exemplary embodiment, the output  26  is connected by a conduit  34  to a coupler  28  that complies with the SAE J1772 connector standard and is configured to couple with a vehicle receptacle. 
     In the exemplary embodiment, the conduit  34  contains one or more output conductors  36 . As will be discussed in more detail below, the output conductors  36  transfer electrical power to the vehicle. The conduit  34  further includes one or more communication lines  38 ,  40 . The communication lines  38 ,  40  provide a communications pathway between the vehicle and the electric vehicle charger  20 . In one embodiment, the electric vehicle charger  20  includes a first communication line  38  that connects with an output communication line  42 . The output communication line  42  may couple to a suitable monitoring or control system, such as but not limited to one or more of: a computer network, a home area network, a wide-area network, a wireless network, or the Internet for example. In another embodiment, the electric vehicle charger  20  may include a second communication line  40  that connects and allows communication between the vehicle and a charger controller  44  within housing  22 . It should be appreciated that in some embodiments, the communications line  38 ,  40  may be integrated into a single communications line. 
     Arranged between the plurality of inputs  24  and the output  26  is a transformer  46 . In the exemplary embodiment, the transformer  46  is a toroidal transformer. The plurality of inputs  24  are connected to the input or primary side of toroidal transformer  46 . Output  26  is connected to the load or secondary side of the toroidal transformer  46 . It should be appreciated that while the windings of the toroidal transformer  46  are described with a single winding having a primary and a secondary side, other transformer constructions, such as but not limited to a transformer having a separate primary winding and secondary winding may also be used. As will be discussed in more detail below, the toroidal transformer  46  provides advantages in combining the electrical power received via conductors  30  and to allow charging of the vehicle at a higher rate. 
     A typical toroidal transformer  46  is described in more detail with reference to  FIG. 2 . The toroidal transformer  46  includes a core  48  that is covered by an insulation material (not shown). A winding  50  with lead cables  52 ,  54 ,  56  and an insulation sleeve  58  wrapped around the cross section of core  48  and distributed along the circumference of the core  48 . The cables  52 ,  54  connect with conductors  30 , while the cable  56  connects with output conductor  36 . The winding  50  is typically fabricated in a toroidal winding machine by threading a circular winding head with a magazine for storing magnet wire through a center hole  60  in core  48 , then storing magnet wire on the magazine, and finally rotating the winding head around the core  48  through the center hole  60  while pealing copper wire off the magazine. The core  48  is rotated slowly about the toroidal axis during winding, so the wire is distributed along the circumference of the core  48 . 
     An insulation portion  62  separates the winding  50  from the transformer core  48 . The insulation portion  62  is typically a strip of plastic film that is wrapped in several layers over the transformer core  48 . The strips are overlapped laterally to provide creep insulation across the strip. Insulation portion  62  is typically made from a plastic such as, but not limited to polyethylene terephtalate (PEPT) film. The winding  50  is wound on top of the insulation portion  62 . A final insulation layer  64  is wrapped around the winding  50  for protection. Alternatively, the toroidal transformer  46  may be potted in plastic to provide the final insulation layer. 
     The electric vehicle charger  20  may further include additional components, such as but not limited to a switch or circuit breaker  66  and indicator lights or LEDs  68 , as shown, for example, in  FIG. 1 . In the exemplary embodiment, the circuit breaker  66  and LEDs  68  are coupled to controller  44 . In one embodiment, the controller  44  includes means for limiting electrical current flowing to the output  26  such as with a variable resistor for example. It should be appreciated that the electric vehicle charger  20  may include additional electrical components for controlling the flow of electrical power through the electric vehicle charger  20  to a vehicle, such electrical components include but are not limited to contactors, relays, fuses, and the like for example. It shall be understood that any “controller”, “controlling device” or other implement receiving inputs from an external device and producing outputs that control the same or another external device may be implemented as a digital microprocessor or as an analog circuit or a combination of both. In the exemplary embodiments, the controller  44  may receive a signal via communication line  40  from the vehicle. In one embodiment, the signal represents a maximum allowable current the vehicle may receive and the controller  44  limits the current level to output  26  to the desired current level in response to the signal from the vehicle. In another embodiment, the controller  44  transmits a signal to the vehicle indicating that the coupler  28  is connected to the vehicle. In yet another embodiment, the controller  44  varies the output electrical power to the vehicle based on a signal received via communication line  40  from the vehicle. 
     Another embodiment of electrical vehicle electric vehicle charger  20  is illustrated in  FIG. 3 . This embodiment is substantially similar to the embodiment of  FIG. 1 . In this embodiment, the plurality of inputs  24  includes a first pair of inputs  70  and a second pair of inputs  72 . The first pair of inputs  70  are coupled to receive electrical power from conductors  30  as discussed herein above. The second pair of inputs  72  are coupled to receive electrical power from conductors  74 . Similar to conductors  30 , the conductors  74  each of a plug  76 . In this embodiment, the plugs  76  are configured to couple to a first type of standard electrical outlet, such as a NEMA 6-30 outlet for example, and plugs  32  are configured to couple to a second type of standard electrical outlet, such as a NEMA 5-15 outlet for example. The pairs of inputs  70 ,  72  are coupled to a switch, such as an A/B switch that selectively couples one of the pairs of inputs  70 ,  72  to the cables  52 ,  54 , such that only one of the pairs of inputs  70 ,  72  provides electrical power to the toroidal transformer  46  at a time. 
     The electric vehicle charger  20  may be used in a variety of applications. An exemplary embodiment of an electrical utility network  78  is illustrated in  FIG. 4 . The utility network  78  includes one or more power plants  80  connected in parallel and transmit power through a transmission network to a main distribution network  82 . The power plants  80  may include, but are not limited to: coal, nuclear, natural gas, or incineration power plants. Additionally, the power plants  80  may include one or more hydroelectric, solar, or wind turbine power plants. It should be appreciated that additional components such as transformers, switchgear, fuses and the like (not shown) may be incorporated into the utility network  78  as needed to ensure the efficient operation of the system. The utility network  78  may be interconnected with one or more other utility networks to allow the transfer of electrical power into or out of the utility network  78 . 
     The main distribution network  82  typically consists of medium voltage power lines, less than 50 kV for example, and associated distribution equipment which carry the electrical power from the point of production at the power plants  80  to the end users located on local electrical distribution networks  84 ,  86 . The local electrical distribution networks  84 ,  86  are connected to the main distribution network  82  by substations  88  which adapt the electrical characteristics of the electrical power to those needed by the end users. Substations  88  typically contain one or more feeders, transformers, switching, protection and control equipment. Larger substations may also include circuit breakers to interrupt faults such as short circuits or over-load currents that may occur. Substations  88  may also include equipment such as fuses, surge protection, controls, meters, capacitors and voltage regulators. 
     The substations  88  distribute the received electrical power through feeders to one or more local electrical distribution networks, such as local electrical distribution network  84 , for example, that provides electrical power to a commercial area having end users such as an office building  90  or a manufacturing facility  92 . These facilities  90 ,  92  may include parking lots  94  or parking garages. In one embodiment, these parking lots  94  include one or more outlets  96 , which operators of electric vehicles may connect the electric vehicle charger  20 . In one embodiment, the outlet  96  may be coupled to a streetlight  98 . In other embodiments, the outlets  96  are coupled to a facility. Local electrical distribution network  84  may also include one or more transformers  100  which further adapt the electrical characteristics of the delivered electricity to the needs of the end users. Substation  88  may also connect with other types of local distribution networks such as residential distribution network  86 . The residential distribution network  86  may include one or more residential buildings  102 ,  104  and also light industrial or commercial operations. In one embodiment, the residential buildings  104  have outlets  96  adjacent the area where the operators park their electrically powered vehicles. 
     Referring now to  FIG. 5 , an exemplary embodiment of a system for controlling the recharging of a vehicle will be described. A vehicle, such as a plug-in hybrid vehicle  106  for example, typically includes an internal combustion engine  108  coupled to a motor  110  through a transmission  112  that transfers the power from the engine  108  and motor  110  to the wheels  114 . A battery  116  is electrically coupled to provide electricity to power the motor  110 . In some embodiments, the motor  110  may be arranged to act as a generator driven by the engine  108  to provide recharging of the battery  116 . The vehicle  106  may include a controller  120  that is arranged to communicate and monitor the performance of the vehicle  106 . It should be appreciated that the battery  116  is referred to as a single component, however, the battery  116  may be comprised of a number of electrochemical cells or discrete individual batteries that are coupled together in series or parallel, depending on the voltage and power needs. The battery  116  is electrically coupled to a receptacle  118  which provides an external connection to electric vehicle charger  20 . A meter  120  is electrically connected between the receptacle  118  and the battery  116  to measure the flow of electrical power to and from the battery  116 . The meter  120  may be similar to Applicants co-pending patent application Ser. No. 11/850,113 entitled “Hybrid Vehicle Recharging System and Method of Operation” or Applicants co-pending patent application Ser. No. 12/399,465 entitled “Metering System and Method of Operation” both of which are incorporated herein in their entirety. The controller  120  may also be connected to communicate with external devices, such as the electric vehicle charger  20 , via the receptacle  118 . It should be appreciated that the meter  120  may be accessible to the controller  120  via the vehicle  106  on-board diagnostic system (e.g. OBD II). 
     The residence  104  receives electrical power from the main distribution network  82  and local electrical distribution network  86  as described herein above. Typically, the electrical power is received by the residence via an electrical meter  122 . The electrical meter  122  has one or more sensors and controllers (not shown) that record the consumption of electrical power by the residence  104 . Typically the electrical meter  122  may be a solid state device having features compatible with the Advanced Metering Infrastructure (“AMI”) or Advanced Meter Reading (“AMR”) to allow the electrical meter  122  to communicate with the electrical utility, the residence  104  home area network, the electric vehicle charger  20  or the vehicle controller  120 . After the electrical meter  122 , the electrical power typically flows into a load center  124  that divides the incoming electrical power and distributes it into multiple electrical circuits  126 ,  128 . Each of the electric circuits typically has one or more electrical outlets, such as outlets  130 ,  132  for example. The electrical circuits  126 ,  128  may be rated as 110 volt, 15 ampere circuit, a 110 volt, 20 ampere circuit, a 220 volt, 20 ampere circuit, a 220 volt, 30 ampere circuit, or a 220V, 50 ampere circuit for example. In some embodiments, the electrical circuits  126 ,  128  may be a 400-480 volt circuit. Further, while the electrical circuits  126 ,  128  are illustrated as a single line, the electrical circuits  126 ,  128  may a multi-phase circuit, such as a three phase circuit for example. In the exemplary embodiment, the outlets  130 ,  132  are configured with interfaces to accept industry standard plugs, such as NEMA 5-15, NEMA 5-20, NEMA 6-20, NEMA 6-30, or NEMA 6-50 plugs for example 
     It should be appreciated that the actual voltage supplied from the local electrical distribution network  86  may vary within industry acceptable tolerances. The voltages and currents discussed herein are for exemplary purposes and the claimed invention should not be so limited. For example a nominal 110 volt circuit may vary between 105 volts to 125 volts, and a 220 volt circuit may vary between 208 volts to 240 volts for example. The load center  124  may further have one or more additional circuits that are dedicated to a particular appliance, such as a furnace, a well pump, an oven or a clothes dryer for example. 
     When the vehicle operator desires to recharge the battery  116 , the coupler  28  on conduit  34  is attached to receptacle  118 . By connecting the coupler  28  to the receptacle  118 , the output conductor  36  and communications line  38 ,  40  of electric vehicle charger  20  are electrically connected to corresponding conductors  134  and communication lines  136  in vehicle  106 . The operator then connects the conductors  30  to the outlets  130 ,  132  allowing electrical power to flow from the residence  104  into the vehicle  106 . Since the electrical power is being provided by two distinct electrical circuits within the residence  104 , the output electrical power from the electric vehicle charger  20  to the vehicle  106  is converted by the toroidal transformer  46  to approximately twice the voltage of the individual electrical circuits  126 ,  128 . Thus, the electric vehicle charger  20  provides the advantages of a SAE J1772 Level 2 charge in locations where only Level 1 capacity circuits are available. Further, if the residence has 220 volt circuits available, the electric vehicle charger  20  may be able to provide approximately a Level 3 charge where only Level 2 capacity circuits are available. In one embodiment, when the toroidal transformer  46  converts the voltage, the output current level is approximately half the input current level. This provides many advantages in reducing the amount of charge time for recharging the battery  116 . 
     In one embodiment, the electric vehicle charger  20 , is configured to be portable and transportable in a vehicle, such as on the rear floor or in the trunk of the vehicle. The electric vehicle charger  20  is sized to fit within constraints such as the rear seat and the front seat so as to limit the width of the electric vehicle charger  20 . In the exemplary embodiment, the housing  22  of the electric vehicle charger  20  is less than 5 inches (12.7 centimeters). A vehicles front seat is typically angled to provide comfort and structural support for a front seat passenger. As such, the front seat vertically constrains the height of the electric vehicle charger  20 . In the exemplary embodiment, the height of the housing  22  is less than 18 inches (45.7 centimeters). Further, in many vehicles, the length of the electric vehicle charger  20  may be constrained by an elevated portion typically located in the center of the car to allow a drive-train to pass from the engine to the rear wheels of the vehicle. In the exemplary embodiment, the width of the housing  22  of electric vehicle charger  20  is less than 18 inches (45.7 centimeters). It should be appreciated that other dimensions may be more appropriate provided that electric vehicle charger  20  remains sized to fit within the desired transportation area in a vehicle without causing damage or unnecessary wear to the vehicle. It is also desirable for the electric vehicle charger  20  to be an appropriate weight to be carried or transported by a single person. In the exemplary embodiment, the electric vehicle charger  20  has a weight of less than 60 lbs (27.2 kg). 
     It should be appreciated that an electric vehicle charger  20  may provide further advantages in facilitating the purchase and adoption of electrically powered vehicles. Since the electric vehicle charger  20  provides a higher level of charge, the amount of time it takes to recharge the battery  116  may be substantially reduced, such as from 24 hours with a Level 1 charge, to between three to six hours with a Level 2 charge for example. This decrease in recharge time may be accomplished without requiring substantial, or in some applications any, installation of additional electrical circuits. Thus a purchaser of an electrically powered vehicle may start fully utilizing the vehicle once it is purchased. 
     It should further be appreciated that the electric vehicle charger  20  provides advantages by allowing the electrically powered vehicle to be charged using standard electrical outlets. Thus, the vehicle operator may keep the electric vehicle charger  20  in vehicle allowing the recharging of the battery at the operators place of employment, such as through the use of outlets  96  for example. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.