Smarter charging of plug-in vehicles

A system is described to enable charging of electric vehicles. A scheduler determines charging profiles for electric vehicles based on a time period within a day that is beneficial to an electric grid while still meeting the needs of drivers of the electric vehicles. A service provider charges the electric vehicles according to the charging profiles.

BACKGROUND

1. Field of Art

The present disclosure generally relates to the field of charging plug-in vehicles.

2. Description of Related Art

An electric vehicle is propelled by an electric motor(s) that uses electrical energy stored in an energy storage device such as a battery. When the electrical energy stored in the energy storage device of an electric vehicle is depleted, the electric vehicle is connected or “plugged-in” to an electrical grid for charging. The electrical grid supplies power to the electric vehicle to charge the energy storage device used by the vehicle.

Generally, electric vehicles are encouraged to charge during off-peak hours of the electrical grid to prevent the increase of loads during on-peak hours. However, setting fixed charging times for off-peak charging of electric vehicles results in most electric vehicles being programmed to start charging at the same time. Given the typical usage of an electric vehicle, the time needed to recharge the vehicle may result in the vehicle being charged well before the time the owner needs the vehicle charged. Accordingly, there is no need to charge electric vehicles at the same off-peak time.

SUMMARY

Renewable energy generation using a natural resource (e.g., wind, sunlight, rain, tides, and geothermal heat) differs every day and during different times of a day depending on the weather. The embodiments disclosed herein provide continuously optimized scheduling of charging for electric vehicles. The electric vehicles are charged in a manner that helps grid operators integrate renewable energy generation to prevent these renewable sources from being wasted while at the same time meeting the needs of drivers to have their cars fully charged.

In one embodiment, a scheduler is an entity operating between a grid operator of an electric grid and a service provider that facilitates charging of electric vehicles. The scheduler communicates with the service provider to determine status information of electric vehicles that need charging. The status information for an electric vehicle may describe how much energy is required by the vehicle, the rate in which the vehicle can be charged, and a time when the charging of the electric vehicle needs to be completed.

The scheduler communicates status information of electric vehicles that need charging to a grid operator and requests a desired power profile from the grid operator based on the status information. The scheduler receives a power profile from the grid operator which describes a time period in which to charge the electric vehicles and the amount of available power to supply to the electric vehicles during the time period. In one embodiment, the time period described by the power profile may correspond to the time in which a renewable energy source (e.g., a wind turbine) is operating at peak energy generation.

The scheduler determines a charging profile for each electric vehicle based on the power profile provided by the grid operator. In one embodiment, a charging profile describes a schedule for charging an electric vehicle. The charging profile may comprise a time in which to begin charging the electric vehicle, a time in which to stop charging the electric vehicle, and a rate in which to charge the electric vehicle. The scheduler develops the charging profile for an electric vehicle such that the vehicle will be charged by the desired time of the associated driver while maximizing the renewable energy supplied by the electric grid. Thus, the scheduler determines schedules for charging the electric vehicles taking into account the needs of all the drivers in a manner that best suits the power profile of the electric grid. The scheduler transmits the charging profiles to the service provider who then charges each electric vehicle according to its associated charging profile.

DETAILED DESCRIPTION

System Architecture

Electric grids are operated by a grid operator that adjusts the generation levels of non-renewable power sources (e.g., fossil fuels) to allow as much renewable energy generation as possible onto the electric grid. However, grid operators may be forced to curtail renewable energy generation (e.g., turn off wind turbines) at times of the day when non-renewable energy sources have been turned down, such as during off-peak hours, due to the lack of energy demand from the grid. Thus, the energy generation from these renewable energy sources is wasted. The embodiments disclosed herein provide continuously optimized scheduling of charging for electric vehicles. The electric vehicles are charged in a manner that helps grid operators integrate renewable energy generation to prevent these renewable sources from being wasted while at the same time meeting the needs of drivers to have their cars fully charged.

FIG. 1illustrates an operating environment100for charging electric vehicles in accordance with one embodiment. Note that although the discussion herein is described with respect to electric vehicles, the embodiments are applicable to any form of plug-in vehicle such as battery powered vehicles or plug-in hybrid vehicles. The operating environment100comprises an electrical grid101, a service provider107, a grid operator103, a scheduler105, electric vehicles113, and a transmission and distribution system111, such as high voltage transmission lines, transformers, and low voltage distribution wiring, that supplies electrical power to loads. The term “load” may refer to a particular power drawing electrical component, e.g., an electric or hybrid car that is plugged into an electrical system to recharge a rechargeable battery inside the car. In the context of the description herein, the load refers to electric vehicles113. However, the embodiments herein may be applied to any type of controllable load that has flexibility in its charging schedule.

Although not shown inFIG. 1, the grid101comprises one or more power plants operated by a supplier, such as an entity owning the power plants. A power plant may be, for example, based on a non-renewable energy source such as a fossil fueled power plant or a nuclear power plant. Alternatively, a power plant may be, for example, based on a renewable energy source such as a solar thermal electric plant, a solar photovoltaic power plant, a hydroelectric power plant, or a wind turbine.

The grid101is overseen by a grid operator103that manages the supply of power on the electrical grid101. For example, the grid operator may be an entity, e.g., an Independent System Operator (ISO) or Regional Transmission Operator (RTO), that is part of, formed at the direction of, or authorized by a government regulatory agency such as the Federal Energy Regulatory Commission (FERC). The government regulatory agency coordinates, controls, and monitors the operation of the electrical power system within a geographical region such as a state or multiple states within the United States of America.

During operation of the grid101, the grid operator103coordinates the supply of power available to be in balance with loads in the electrical grid101including electric vehicles113. The grid operator103or a computer system of the operator103determines the amount of supply necessary and contracts with various energy suppliers to provide such power. In response to a signal sent through a communication network109, e g., the Internet, from a computer system of the operator103, a computer system of the supplier can increase or decrease the power generated by a power plant supplied to the loads. That is, the grid operator103increases or decreases the power sent by the power plant through the transmission and distribution system111to the electrical grid101, and thus to the electric vehicles113.

In one embodiment, the grid operator103develops desired power profiles for charging electric vehicles113. A power profile describes a specific time period in which to charge electric vehicles113and the amount of available power to supply to the electric vehicles113during the time period defined by the power profile. The time period may comprise a whole day or a specific time period within a given day in which to charge electric vehicles113.

In one embodiment, the specific time period described by a power profile corresponds to a duration of time in which a renewable energy source (e.g., a wind turbine) is operating at peak energy generation. Thus, the power profile developed by the grip operator103maximizes the renewable energy generated by the renewable energy source. By developing the power profile based on the time period associated with peak energy generation by the renewable power source, the grid operator103prevents curtailing of the renewable energy source because the renewable energy is being utilized to charge electric vehicles113.

The grid operator103may also develop the desired power profile based on the needs of the drivers of the electrical vehicles113. As will be further described below, an electrical vehicle113may require a particular amount of energy for charging and may need to be charged by a specific time to accommodate the needs of the driver of the vehicle. The grid operator103may develop a desired power profile to account for the total amount of energy required to charge a plurality of electrical vehicles113that meet the time requirements of the drivers of the electrical vehicles113.

FIG. 2Aillustrates an example of a power profile200generated by the grid operator103. The power profile200is a function of time and power and is developed to coincide with the time period of peak energy generation by a renewable power source. The power profile200indicates that electric vehicles113may begin charging at time t1. The amount of power available for charging electric vehicles113increases between time t1and time t2. The maximum power generated by the renewable energy source is reached at time t2and is available for charging electric vehicles113until time t3. From time t3, the amount of renewable energy available to charge electric vehicles113decreases from maximum power to zero at time t4. Thus, power profile200describes a specific time range (time t1to time t4) and the amount of available power during the time range to charge electric vehicles113.

Referring back toFIG. 1, the service provider107facilitates charging of electric vehicles113. A service provider107may represent car companies (e.g., NISSAN) or charging station network operators (e.g., COULOMB TECHNOLOGIES). In one embodiment, the service provider107facilitates charging of an electric vehicle113according to a charging profile specific to the electric vehicle113as will be further described with respect to the scheduler105. Rather than immediately charging an electric vehicle113when the vehicle is connected to a charging station at the service provider107, the service provider107communicates with the charging station to charge the electric vehicle113according to its associated charging profile. Alternatively, the service provider107may communicate directly with electric vehicles113instructing the vehicles113to charge according to their respective charging profiles. Charging electrical vehicles113according to their charging profiles prevents the unnecessary charging of the electrical vehicles113at the same time.

As individual electric vehicles113are plugged into a charging station provided by the service provider107, the service provider107may communicate with the electric vehicles via existing cellular data connections in the vehicles113or other communication means to request vehicle status information. The service provider107aggregates the vehicle status information into a file and communicates the aggregated vehicle status information to the scheduler105along with requests for charging profiles for the electric vehicles113. In one embodiment, the service provider107receives one or more of the following vehicle status information from an electrical vehicle113:a vehicle identifier (ID) that uniquely identifies the electric vehicle113;an approximate location (e.g., geospatial identifiers) of the electric vehicle113;an amount of charging energy required by the electric vehicle113in kilowatt hour (kWh);a maximum charging rate in kilowatt (kW) of the electric vehicle113;an earliest time when charging of the electric vehicle113can begin; anda time when charging of the electric vehicle113needs to be completed.

In one embodiment, the amount of charging energy required by the electric vehicle113corresponds to an amount needed for the electrical vehicle113to reach full charge (i.e., maximum capacity). Alternatively, the amount of required energy may correspond to an amount that is less than the maximum capacity of the electrical vehicle113. For example, the driver may specify that he or she only needs the electric vehicle113to be charged to half the maximum capacity of the electrical vehicle113.

The earliest time when the electrical vehicle113can begin charging may be associated with a time when the vehicle is no longer in use by the driver and thus can begin charging and/or when the electrical vehicle113is plugged into a charging station. In another embodiment, the earliest time when the electrical vehicle113may begin charging is associated with a time at which off-peak electricity rates start. The time when charging of the electrical vehicle113needs to be completed is associated with when the driver needs charging of the electrical vehicle113to be completed so that the driver may use the vehicle. For example, the driver may specify that he or she needs the electrical vehicle113to be charged to the required amount by 9 AM. Alternatively, the service provider107may specify the time of charging completion if the driver does not provide a time for completion.

The scheduler105(e.g., GOOGLE INC.) is the entity operating between the grid operator103and the service provider107. The scheduler105determines charging profiles for electric vehicles113in response to requests for the charging profiles from the service provider107. In one embodiment, a charging profile for an electric vehicle113comprises a start time describing a time in which to begin charging the electric vehicle113and an end time describing a time in which to stop charging the electric vehicle113. The start time for an electric vehicle113typically corresponds to a time after the electric vehicle113is plugged in for charging at the service provider107. Generally, the start time corresponds to a time that allows enough time to charge the electric vehicle113by the desired time indicated in the status information for the vehicle113. At the latest, the end time will correspond to the time when charging of the electric vehicle needs to be completed as indicated in the vehicle status information for the electric vehicle113. The charging profile may further comprise a charging rate in which to charge the electric vehicle113. The charging rate may correspond to the maximum charging rate of the electric vehicle or a rate that is less than the maximum charging rate, or a variable charging rate.

The scheduler105generates the charging profile for each electric vehicle113according to the desired power profile provided by the grid operator103, the vehicle status information for the electric vehicle113, and the vehicle status information for the other electric vehicles113that need to be charged. Particularly, the scheduler105determines the start time to begin charging the electric vehicle113based on the allocated time period for charging electric vehicles113described by the power profile of the grid101, the required time that the electric vehicle113should be done charging, the amount of energy required by the electric vehicle113to reach the desired charge, and the charge rate of the electric vehicle113. The scheduler105generates the charging profiles for the electric vehicles113to ensure that all electric vehicles113that need charging are charged by the required time indicated in the status information for the vehicles113. In one embodiment, the scheduler105may implement a first-fit algorithm or a best fit decreasing algorithm to determine the charging profile for each electric vehicle113based on the power profile provide by the grid operator103. Once the charging profiles for the electric vehicles111are determined by the scheduler105, the scheduler105communicates the charging profiles to the service provider107. Note that in one embodiment, the scheduler105and service provider107may be a single entity that performs the functions described herein of the scheduler105and service provider107.

In one embodiment, the scheduler105may update charging profiles for electric vehicles113that are nearing their start time for charging (i.e., vehicles that have yet to begin charging). The scheduler105may receive an indication from the service provider107that an electric vehicle113is scheduled to begin charging within a threshold time of the start time for the vehicle such as 1 hour from the start time. The scheduler105may communicate with the grid operator103to determine an updated power profile that accounts for current energy generating conditions of the renewable energy source. Based on the updated power profile, the scheduler105may generate an updated charging profile for the electric vehicle and communicate the updated charging profile to the service provider107. The updated power profile may comprise an updated start time, updated end time, and/or updated charging rate for the electrical vehicle113that is distinct from the start time, end time, and/or charging rate originally specified in the charging profile for the electrical vehicle113.

The scheduler105may also receive, from the service provider107, actual charging information from the electric vehicles113that were charged according to the charging profiles developed by the scheduler105. The charging information for each electrical vehicle113describes the actual start time in which the vehicle actually began charging, the actual end time in which the vehicle actually completed charging, and the actual rate in which the vehicle was charged. The scheduler105may utilize the actual charging information to better develop charging profiles for electric vehicles in the future taking into account any delays when vehicles actually began and completed charging.

FIG. 2Billustrates the desired power profile200ofFIG. 2Aincluding a plurality of charging profiles201for electric vehicles113that need charging.FIG. 2Billustrates a total of 9 charging profiles201(201A through201I) for electric vehicles113. A charging profile for an electric vehicle113is represented by a rectangle inFIG. 2B. The width of each rectangle indicates the start time and end time in which an associated electric vehicle113is charged in accordance with the desired power profile200. As shown inFIG. 2B, each of the electric vehicles113represented by the charging profiles begins and ends charging at different times rather than the vehicles synchronously charging at the same time until completion. The height of each rectangle indicates the rate at which the associated electric vehicle113will be charged. Note that althoughFIG. 2Billustrates a uniform rate of charging for each electric vehicle113for simplicity of illustration, the rate of charging may vary during the time in which the vehicle is charging or may vary from vehicle to vehicle.

Schemes for Charging Electric Vehicles

FIG. 3illustrates one embodiment of the interaction between the grid operator103, scheduler105, service provider107, vehicle1, and vehicle2to charge the vehicles. Note that in other embodiments, other steps may be performed other than those illustrated inFIG. 3.

Vehicle1and vehicle2both transmit301their associated status information to the service provider107. Vehicle1and2may use their existing cellular data connections to communicate the status information to the service provider107. As described above, the status information for each vehicle comprises a vehicle ID, the location of the vehicle, an amount of charging energy required by the vehicle, a maximum charging rate, an earliest time when the vehicle can begin charging, and a time when the vehicle should be done charging. The service provider107aggregates303the status information for vehicle1and vehicle2for communication to the scheduler105.

The service provider107requests305charging profiles for vehicles1and2. The request includes the aggregated status information for the vehicles. The scheduler105transmits307the aggregated status information to the grid operator103. The grid operator103determines309a power profile in which to serve the energy required by vehicle1and vehicle2that takes into consideration the peak energy generation of a renewable energy source and the needs of the drivers as indicated in the aggregated status information. The grid operator103transmits311the power profile to the scheduler105. The scheduler105determines313charging profiles for vehicle1and vehicle2based on the power profile received from the grid operator103and the status information of the vehicles.

The scheduler105transmits315the charging profiles to the service provider107. The service provider107charges317vehicle1and vehicle2according to their respective charging profile which describes the start time, end time, and charging rate for each vehicle. Vehicle1and vehicle2may transmit319charging information to the service provider319indicating the actual charge start time, actual stop time, and actual rate of charge. The service provider107aggregates321the charging information and transmits323the charging information to the scheduler105. Based on the charging information, the scheduler105may optimize325the charging algorithms used to determine the charging profiles for electric vehicles313taking into account any delay regarding when the electrical vehicles actually begin charging and finish charging.

FIG. 4illustrates one embodiment of the interaction between energy suppliers401, the scheduler105, service provider107, vehicle1, and vehicle2to charge the vehicles. In one embodiment, energy suppliers401represent various entities that supply energy for the electrical grid101. Each energy supplier401submits bids describing a cost (e.g., 3 cents per kWh) of energy supplied by the energy supplier401. The scheduler105purchases energy from the energy supplier401based on the received bids as will be described below. Note that in other embodiments, other steps may be performed other than those illustrated inFIG. 4.

Similar toFIG. 3, vehicle1and vehicle2both transmit403their associated status information to the service provider107. The service provider107aggregates405the status information for vehicle1and vehicle2for communication to the scheduler105. The service provider107requests407charging profiles for vehicles1and2. The request includes the aggregated status information for the vehicles.

In one embodiment, the energy suppliers401transmit bids413to a marketplace409. The marketplace409comprises a virtual location (e.g., an online website) in which energy suppliers401provide bids for their energy. Each energy supplier401includes in the bid a cost of energy supplied by the energy supplier401. A bid may include a desired power profile in which the energy supplier401can provide their energy in one embodiment. The scheduler105purchases411energy from the marketplace409from an energy supplier401.

In one embodiment, the scheduler105selects an energy supplier401based on the needs of the vehicles as described in the aggregated status information received from the service provider107. The scheduler105may analyze the power profiles from the energy suppliers401to determine which energy supplier can provide energy which fits energy needs of the vehicles. That is, the scheduler105determines which energy supplier can supply energy to charge the vehicles by the requested time indicated in the vehicle status information. The scheduler105may also select an energy supplier401based on cost. The scheduler105may select an energy supplier401that fits the energy needs of the vehicles at the lowest cost.

Once energy is purchased, the scheduler105determines412a power profile in which energy is served to vehicle1and vehicle2. Note that in alternative embodiments, the power profile included in a bid by an energy supplier401is utilized. The scheduler105then determines413charging profiles for vehicle1and vehicle2based on the determined power profile and the status information of the vehicles. The scheduler105transmits415the charging profiles to the service provider107. The service provider107charges417vehicle1and vehicle2according to their respective charging profile which describes the start time, end time, and charging rate for each vehicle. Vehicle1and vehicle2may transmit419charging information to the service provider107indicating the actual charge start time, actual stop time, and actual rate of charge. The service provider107aggregates421the charging information and transmits423the charging information to the scheduler105. Based on the charging information, the scheduler105may optimize423the charging algorithms used to determine the charging profiles for electric vehicles313.

Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic is included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” or “a preferred embodiment” in various places in the specification are not necessarily referring to the same embodiment.

Certain aspects disclosed herein include process steps and instructions described herein in the form of a method. It should be noted that the process steps and instructions described herein can be embodied in software, firmware or hardware, and when embodied in software, can be downloaded to reside on and be operated from different platforms used by a variety of operating systems.

While the disclosure has been particularly shown and described with reference to a preferred embodiment and several alternate embodiments, it will be understood by persons skilled in the relevant art that various changes in form and details can be made therein without departing from the spirit and scope of the invention.