CHARGING SYSTEM FOR ELECTRIC VEHICLES
An electric vehicle charging system includes a power distributing system configured to receive power from a power control system and selectively direct the power to one of a plurality of power dispensers coupled to the power distribution system.
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This application claims the benefit of U.S. Provisional Application No. 62/818,884, filed Mar. 15, 2019, the disclosure of which is incorporated herein by reference in its entirety.
TECHNICAL FIELDThe current disclosure relates to a charging system for electric vehicles.
BACKGROUNDElectric vehicles, such as buses, cars, trucks, etc. are charged at a charging station to recharge their batteries. In the case of a fleet of electric vehicles, multiple vehicles may be recharged at the same time (e.g., when they are parked overnight at a depot, when multiple vehicles pull into a charging station, etc.). In the case of a large fleet (such as, for example, a fleet of electric buses), a reduction in operating costs can be achieved by reducing the infrastructural and other costs associated with charging (such as, for example, decreasing number of chargers, increasing the number of vehicles that can be charged at the same time, etc.). Embodiments of the current disclosure may result in a decrease in charging related costs for electric vehicles. The scope of the current disclosure, however, is defined by the attached claims, and not by the ability to solve any specific problem.
SUMMARYEmbodiments of the present disclosure relate to, among other things, charging system for electric vehicles. In one embodiment, an electric vehicle charging system is disclosed. The charging system includes a power distributing system configured to receive power from a power control system and selectively direct the power to one of a plurality of power dispensers coupled to the power distribution system.
In one embodiment, an electric vehicle charging system is disclosed. The electric vehicle charging system may include a power control system configured to receive power from a utility grid, a power distribution system configured to receive power from the power control system, and a first power dispenser and a second power dispenser coupled to the power distribution system. The first power dispenser and the second power dispenser may each be configured to direct power to an electric vehicle. And, the power distribution system may be configured to selectively direct the received power to one of the first and second power dispensers.
In another embodiment, a method for charging electric vehicles is disclosed. The method may include releasably coupling a first power dispenser to a first electric vehicle and a second power dispenser to a second electric vehicle. The first and second power dispensers may be coupled to a power distribution system, and the power distribution system may be coupled to a power control system. The method may also include directing power from the power control system to the power distribution system, and selectively directing power from the power distribution system to the first power dispenser without directing power to the second power dispenser.
In another embodiments, a power distribution system configured to charge a first electric vehicle and a second electric vehicle is disclosed. The power distribution system may include a first power dispenser and a second power dispenser. The power distribution system may also include a first contactor, a second contactor, and a control unit. The first contactor may electrically couple the first power dispenser to a power control system and the second contactor may electrically couple the second power dispenser to the power control system. The control unit may be configured to receive power from the power control system, receive information regarding the first electric vehicle coupled to the first power dispenser and the second electric vehicle coupled to the second power dispenser. The control unit may also be configured to determine to charge the first electric vehicle prior to the second electric vehicle based on the received information, selectively direct power to the first dispenser coupled to the first electric vehicle by activating the first contactor and deactivating the second contactor, and as a result of determining that the first electric vehicle is charged, selectively direct power to the second dispenser coupled to the second electric vehicle by activating the second contactor and deactivating the first contactor.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present disclosure and together with the description, serve to explain the principles of the disclosure.
The present disclosure describes a charging system for electric vehicles. While principles of the current disclosure are described with reference to specific types of electric vehicles, it should be understood that the disclosed charging systems and methods may be used in any electric vehicle application.
It should be noted that, although EV 10 is described as having a charge port 12, and dispenser 60 is described as having a corresponding connector 62 that plugs into the charge port 12, this connection method is only exemplary. Any known method may be used to connect an EV to a dispenser. In some embodiments, EV 10 may include a different type of charging interface (in addition to, or in place of, charge port 12) that interfaces with a corresponding charging interconnection of a charging station. For example, the charging interface of EV 10 may include charge-receiving electrodes positioned on the roof (or another surface such as the side surface) of EV 10, and the charging interconnection (of charging station) may include charging electrodes attached to an inverted pantograph that descends (or extends) to bring the charging electrodes in contact with the charge-receiving electrodes of EV 10. See
In some embodiments, electric current from a utility grid 15 (e.g., single phase or three-phase AC current from a utility company that supplies power in a geographic locality) may be directed to PCS 20 (power control system). This AC current may be converted to DC current at PCS 20 and distributed to the various dispensers 60 (i.e., dispensers 60A-60E) via PDS 40 (power distributing system). PCS 20 may include electrical components (e.g., transformer, rectifier, power converter, switches, safety mechanisms, etc.) that convert the AC grid current to the DC current. For example, in some embodiments, the utility grid 15 may provide AC current having at a high voltage, for example, at a voltage between about 12-33 kV, to PCS 20. A transformer in PCS 20 may step down this voltage to a lower voltage, e.g., 750V, and a rectifier of PCS 20 may convert the AC current to DC current. This DC current may then be provided to one or more dispensers 60 as will be described below. In some embodiments, PCS 20 may include (or may be coupled to) a secondary power delivery system 24, for example, to provide backup power to EV 10. Power from secondary delivery system 24 may be used to charge EV 10 at times of need (e.g., grid shutdown, voltage fluctuations. etc.) and/or to reduce cost (e.g., during times of high energy cost). Secondary power delivery system 24 may include any type of power generation device (e.g., solar panels, wind turbines, gas/diesel generators, etc.) or power storage device (e.g., capacitors, external battery packs, etc.) that can provide power to EV 10. In some embodiments, power from secondary power delivery system 24 may also be directed to the buses 10 via PDS 40 and dispensers 60. PCS 20 may include a control unit 22 configured to manage the delivery of power to the dispensers 60. For example, control unit 22 may selectively direct power from utility grid 15 or secondary power deliver system 24 to the dispensers 60 based on power availability, energy cost, etc. PCS 20 may also include a communications system 26 with components configured to communicate with an external source (e.g., an EV 10, a control station that controls operation of a fleet of EVs 10, utility company, etc.) via a wired or a wireless (e.g., cellular network, internet, etc.) connection. Using communications system 26, PCS 20 may communicate with the external source to transmit data (e.g., current state of charge of EV 10, total energy consumed in charging EVs, details (identification number, etc.) of the EVs 10 being charged, etc.) and to receive information (e.g., energy cost at that time from utility company, schedule and other information of EVs 10, etc.).
PDS 40 may be configured to receive power from PCS 20 and direct the power to the one or more dispensers 60 (e.g., dispensers 60A-60E) connected to it. In some embodiments, PDS 40 may direct power to dispensers 60 sequentially or in a serial manner. That is, in such embodiments, PDS 40 directs power to only one of the dispensers 60 connected to it at one time. If only one of the dispensers 60 (e.g., dispenser 60A) has an EV 10 connected to it, PDS 40 will direct power to only dispenser 60A. In some embodiments, even if EVs 10 are connected to multiple dispensers 60 (e.g., dispensers 60A, 60C, and 60E as illustrated in
PDS 40 includes a control unit 46 (e.g., a microcontroller, etc.) configured to control and monitor the operations of PDS 40. Among other functions, control unit 46 may selectively open and close (i.e., selectively activate) contactors 44A, 44B, 44C, 44D. For example, by selectively activating contactor 44A (i.e., closing contactor 44A and opening contactors 44B, 44C, and 44D), control unit 46 selectively directs power from PCS 20 to dispenser 60A. Similarly, by selectively activating contactor 44C (i.e., closing contactor 44C and opening contactors 44A, 44B, and 44D), control unit 46 selectively directs power from PCS 20 to dispenser 60C. Thus, by selectively activating contactors 44A-44D, control unit 46 selectively directs power to one of dispensers 60A-60D to charge the EV 10 coupled to that dispenser. PDS 40 may selectively energize dispensers 60 in any order by activating the corresponding contactors (e.g., 60A→60B→60C→60D→60E; 60C→60A→60E→60D→60B, etc.). As will be described in more detail below, control unit 46 may selectively activate contactors 44A-44D based on a priority for charging the EVs 10 connected to dispensers 60A-60D.
PDS 40 may include a communications system 48 configured to communicate (wirelessly or wired) with an external source (e.g., PCS 20, dispenser 60, a charging controller located in or remote from charging system 100, etc.). The data/information communicated to (e.g., received by) communications system 48 may be indicative of the priority for charging the EVs 10 connected to dispensers 60A-60D (i.e., EVs 10A and 10B). For example, in embodiments where charging system 100 is configured to charge EVs of a fleet (e.g., a fleet of electric transit buses (EV 10A, EV 10B, etc.) operating in fixed routes in a city, etc.), a charging controller (e.g., a control system housed in a control center that manages the operation of the fleet) may determine the priority for charging the EVs (based on factors such as, for example, schedule of the buses, how much charge is needed, energy cost, if a bus is late, etc.) and send instructions to PDS 40 indicating which EV 10 (e.g., EV 10A) is to be charged first, which EV 10 (e.g., EV 10B) to charge second, etc. In embodiments where an EV of a fleet is being charged at charging system 100, the control system of the fleet control center may be aware of the schedule of all the EVs and therefore may be well suited to prioritize the charging of the EVs being charged at the different dispensers. In some embodiments, these instructions may also include charging parameters (e.g., how long to charge, the charge current, etc.) for each EV 10. Based on data/information received by communications system 48, control unit 46 may determine which of the dispensers 60A, 60B, 60C, or 60D to activate. In some embodiments, control unit 46 (or another control unit associated with charging system 100) may determine the priority of charging based on other factors. For example, in some embodiments, the priority for charging may be based on default schedule programmed in control unit 46 (e.g., a first-in, first-out order). That is, the EV (e.g., EV 10A) that is connected to a dispenser 60 (i.e., dispenser 60A) first will be charged first, and the EV that connected to a dispenser 60 next will be charged next, etc.
Each dispenser 60 may include components configured to receive power from PDS 40 and direct the power to EV 10. In some embodiments, some or all dispensers 60 may also be configured for bi-directional power transfer (i.e., configured to transfer power from PCS 20 to EV 10 and transfer power from EV 10 to PCS 20). Each dispenser 60 may also include components (e.g., isolation transformer, etc.) configured to isolate an EV 10 (e.g., EV 10) connected to that dispenser (e.g., dispenser 60A) from EVs (e.g., EV 10C) connected to other dispensers (e.g., dispenser 60C). Each dispenser 60 may also include a control unit configured to communicate with the EV connected to that dispenser and control units 22, 48 (of PCS 20 and PDS 40) to control the charging process. For example, control unit 65A of dispenser 60A may communicate with EV 10A (or a charge controller of EV 10A) to determine (for example) the current state of charge (SOC) of EV 10A. Control unit 65A may then determine the parameters for charging EV 10A (e.g., voltage, current, etc. for charging) based on its SOC, and instruct control unit 22 of PCS 20 (and/or control unit 46 of PDS 40) to deliver power having the determined parameters (voltage, magnitude, etc.) to dispenser 60A to charge EV10A. In some embodiments, when power is directed from PCS 20 to dispenser 60A (i.e., when contactor 44A of PDS 40 is activated), control unit 65A acts as the master controller and control unit 22 of PCS 20 acts as the slave controller. That is, control unit 22 follows the instructions of control unit 65A. Similarly, control unit 65C of dispenser 60C determines the charge current and/or voltage for charging EV 10C based on its SOC. And, when contactor 44C of PDS 40 is activated, control unit 65C acts as the master control unit and instructs control unit 22 (of PCS 20) to direct power having the determined parameters to EV 10C (i.e., control unit 22 acts as the slave controller).
In some embodiments, some of the functions described above with reference to one control unit (e.g., control unit 22, 46, 65A) may be performed by another control unit. In some embodiments, some of these control units (e.g., control unit 22, 46, 65A) may be combined. In general, these control units may include memory and logic devices and may be configured to store data and perform arithmetic operations on data. These control units (collectively or individually) may control the charging of EVs 10 connected to the charging system 100 and the discharge of power from these EVs 10 to the utility grid 15 (referred to as vehicle-to-grid or V2G). That is, in some embodiments, the control units of charging system 100 are not only configured to pull power from utility grid 15 to charge EVs 10, but are also configured to feed power back into utility grid 15 from EVs 10. In some embodiments, these control units may also control the discharge of power from some EVs 10 (e.g., EV 10A) to the utility grid 15 while directing power from the grid 15 to other EVs 10 (e.g., EV 10C).
It should be noted that although PCS 20 is described as converting AC current to DC current and then directing the DC current to PDS 40, this is not a requirement. In some embodiments, PCS 20 receives DC current as input and outputs DC current to PDS 40. For example, a secondary power source (e.g., including a bank of battery packs, a solar cell array, etc.) may input DC current into PCS 20, and PCS may direct that DC current (either without any change or after modifying (e.g., stepping down/stepping up voltage, etc.) the current) to PDS 40. It is also contemplated that, in some embodiments, PCS 20 may direct AC current to PDS 40. In such embodiments, either PDS 40 or inverters positioned upstream (e.g., between PCS 20 and PDS 40) or downstream of PDS 40 (e.g., in dispenser 60 or between dispenser 60 and PDS 40) may convert the AC current to DC current.
In an application where charging system 100 is used to charge a fleet of vehicles, such as, for example, a fleet of electric buses (e.g., electric school buses), many of these buses may be parked at a depot for extended periods (overnight, between shifts, etc.) of time. For example, electric school buses may be parked in the depot when they are not used to transport students to school and return students home.
In some embodiments, each PDS may be connected to (i.e., powered by) a separate PCS. That is, as illustrated in
A PCS is significantly more expensive than a dispenser. In prior art charging systems, a single dispenser is connected to a PCS and used to charge an EV. Coupling multiple dispensers to a PCS (via a PDS) enables multiple EVs to be charged using a single PCS thus saving cost. Although only one dispenser (of the multiple dispensers coupled to the PCS) is activated at one time (and thus only one EV connected to the PCS is charged at one time), significant cost savings can be achieved. For example, multiple EVs parked overnight in a depot can be connected to a single PCS (via the PDS) and charged in sequence one after the other without having to physically disconnect one EV and connect another EV. Additionally, a PCS is physically much larger than a dispenser. Coupling multiple dispensers to a single PCS via a PDS enables the larger PCS to be positioned at a remote location in the depot while the smaller dispensers are distributed in the EV parking area thus increasing parking density. See
While principles of the present disclosure are described with reference to specific embodiments, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, embodiments, and substitution of equivalents all fall within the scope of the embodiments described herein. Accordingly, the invention is not to be considered as limited by the foregoing description. For example, while certain features have been described in connection with various embodiments, it is to be understood that any feature described in conjunction with any embodiment disclosed herein may be used with any other embodiment disclosed herein.
Claims
1-20. (canceled)
21. An electric vehicle charging system, comprising:
- a power control system configured to receive power from a utility grid;
- a power distribution system configured to receive power from the power control system; and
- a first power dispenser and a second power dispenser coupled to the power distribution system, wherein
- the first power dispenser and the second power dispenser are each configured to direct power to an electric vehicle, and wherein the power distribution system is configured to selectively direct the received power to one of the first and second power dispensers, and
- the first power dispenser and the second power dispenser each include a communication system configured to communicate with both (1) the electric vehicle and (2) at least one of the power distribution system or the power control system.
22. The electric vehicle charging system of claim 21, wherein one or more of the first power dispenser and the second power dispenser communicates with the electric vehicle to determine a current state of charge of the electric vehicle.
23. The electric vehicle charging system of claim 22, wherein the first power dispenser and the second power dispenser determine the power to deliver to the electric vehicle.
24. The electric vehicle charging system of claim 23, wherein the first power dispenser and the second power dispenser provide instructions to at least one of the power distribution system and the power control system.
25. The electric vehicle charging system of claim 24, wherein the first power dispenser and the second power dispenser communicate with both the power distribution system and the power control system.
26. The electric vehicle charging system of claim 21, wherein the power distribution system or the power control system include control system communication with one or more of the first power dispenser and the second power dispenser.
27. The electric vehicle charging system of claim 21, wherein one or more of the first power dispenser and the second power dispenser include an isolation transformer for isolating the electric vehicle from other dispensers of the power distribution system.
28. The electric vehicle charging system of claim 21, wherein one or more of the first power dispenser and the second power dispenser is bidirectional.
29. The electric vehicle charging system of claim 21, wherein the power distribution system includes one or more contactors.
30. The electric vehicle charging system of claim 21, further comprising a third power dispenser and a fourth power dispenser coupled to the power distribution system, wherein the third power dispenser and the fourth power dispenser are each configured to direct power to an electric vehicle, and wherein the power distribution system is configured to selectively direct the received power to one of the first, second, third, and fourth power dispensers.
31. A method of charging an electric vehicle comprising:
- releasably coupling a first power dispenser to a first electric vehicle and a second power dispenser to a second electric vehicle, wherein the first and second power dispensers are coupled in a parallel manner to a power distribution system, and the power distribution system is coupled to a power control system;
- electrically coupling the first dispenser to the power control system;
- electrically coupling the second dispenser to the power control system;
- receiving information regarding the first electric vehicle and the second electric using a communications system communicatively coupled with the power control system, the information causing the first electric vehicle and the second electric vehicle to be charged;
- selectively directing power from one of the first power dispenser and the second power dispenser without directing power to the other of the first power dispenser and the second power dispenser based on the information.
32. The method of claim 31, wherein one or more of the first power dispenser and the second power dispenser communicates with the electric vehicle to determine a current state of charge of the electric vehicle.
33. The method of claim 32, wherein one or more of the first power dispenser and the second power dispenser determines a power to deliver to the electric vehicle.
34. The method of claim 33, wherein one or more of the first power dispenser and the second power dispenser provides instructions to at least one of the power distribution system or the power control system.
35. The method of claim 34, wherein one or more of the first power dispenser and the second power dispenser communicate with both the power distribution system and the power control system.
36. The method of claim 31, wherein one or more of the power distribution system and the power control system includes control system communication with the first power dispenser or the second power dispenser.
37. The method of claim 31, wherein one or more of the first power dispenser and the second power dispenser include an isolation transformer and determine which dispenser will provide power to the electric vehicle.
38. The method of claim 31, wherein one or more of the first power dispenser and the second power dispenser are bidirectional.
39. A power distribution system comprising:
- a plurality of power dispensers, each of the plurality of power dispensers electrically coupled to a power control system through the power distribution system, the power control system electrically coupled to an electrical grid and the power distribution system comprising a power distribution communications system; and
- a control unit configured to: receive power from the power control system; receive information regarding a plurality of electric vehicles coupled to the plurality of power dispensers via the power distribution communications system; determine to charge one or more of the plurality of electric vehicles based on the information received via the power distribution communications system; selectively direct power to one or more of the plurality of electric vehicles coupled to the plurality of power dispensers based on the determination.
40. The power distribution system of claim 39, wherein one or more of the electric vehicles is an electric bus.
Type: Application
Filed: Dec 23, 2022
Publication Date: Apr 27, 2023
Applicant: Proterra Operating Company, Inc. (Burlingame, CA)
Inventors: Hayley CASHDOLLAR (San Mateo, CA), Dustin GRACE (San Francisco, CA)
Application Number: 18/145,940