SMART ELECTRIC VEHICLE (EV) CHARGING AND GRID INTEGRATION APPARATUS AND METHODS

• US 20130179061A1
• Filed: 12/04/2012
• Published: 07/11/2013
• Est. Priority Date: 06/10/2010
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Gadh, Rajit, Chu, Chi-Cheng, He, Lei, Shi, Yiyu, Mal, Siddhartha, Prabhu, Shivanand, Panchal, Jay, Sheikh, Omar, Chung, Ching-Yen, Xiao, Bingjun
• Granted Patent: US 9,026,347 B2
• Time in Patent Office: Days
• US Class Current: 701/123
• CPC Class Codes: B60L 53/30 Constructional details of charging stations
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/51 Photovoltaic means
• CPC Class Codes: B60L 53/63 in response to network capacity
• CPC Class Codes: B60L 53/67 Controlling two or more charging stations
• CPC Class Codes: B60L 55/00 Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H02J 2310/64 The condition being economic, e.g. tariff based load management
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 30/12 Remote or cooperative charging
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing
• CPC Class Codes: Y04S 50/10 : Energy trading, including energy flowing from end-user application to grid

Abstract

An expert system manages a power grid wherein charging stations are connected to the power grid, with electric vehicles connected to the charging stations, whereby the expert system selectively backfills power from connected electric vehicles to the power grid through a grid tie inverter (if present) within the charging stations. In more traditional usage, the expert system allows for electric vehicle charging, coupled with user preferences as to charge time, charge cost, and charging station capabilities, without exceeding the power grid capacity at any point. A robust yet accurate state of charge (SOC) calculation method is also presented, whereby initially an open circuit voltage (OCV) based on sampled battery voltages and currents is calculated, and then the SOC is obtained based on a mapping between a previously measured reference OCV (ROCV) and SOC. The OCV-SOC calculation method accommodates likely any battery type with any current profile.

Claims

1. A power grid expert system (PGES), comprising:

(a) a charging station configured for charging a battery in an electric vehicle from an electric power grid;

(b) the charging station optionally comprising a grid tie inverter configured for backfilling power from an electric vehicle connected to the charging station into the electric power grid;

(c) a PGES computer; and

(d) programming that is executable on the PGES computer for performing steps comprising;

selectively controlling a charging of the battery in the electric vehicle by the charging station;

or

if the charging station has the grid tie inverter, then;

selectively controlling a discharging of the battery for backfilling power to the electric power grid from the battery in the electric vehicle.

2. The PGES of claim 1, wherein the charging station is configured for wirelessly communicating information to the electric vehicle, the information selected from the group consisting of:

a location of the charging station;

a charge capacity of the charging station;

whether or not the grid tie inverter is present; and

a recent cost per kWh of charge at the charging station.

3. The PGES of claim 1, further comprising:

a control center; and

communications equipment configured for communications among the control center, the charging station, and the electric vehicle.

4. The PGES of claim 3, wherein a transceiver resident on the electric vehicle acquires one or more pieces of information from the electric vehicle selected from a group of data consisting of:

a geographical position of the electric vehicle;

a state of charge of the battery in the electric vehicle;

a speed of the electric vehicle;

a current draw from the battery in the electric vehicle;

a state of health of the battery in the electric vehicle; and

an identification of the electric vehicle.

5. A battery management system (BMS) for managing a battery in an electric vehicle, the apparatus comprising:

(a) a BMS computer;

(b) a voltage sensor, connected to the BMS computer, for measuring battery voltage;

(c) a current sensor, connected to the BMS computer, for measuring battery current; and

(d) programming that is executable on the BMS computer for performing steps comprising;

mapping a reference open circuit voltage (ROCV) to a reference state of charge (RSOC) of the battery through a discharge cycle to produce an ROCV-RSOC mapping;

measuring a current and a voltage over a period of time from the battery;

calculating an open circuit voltage (OCV) of the battery under a load; and

using the ROCV-RSOC mapping for determining an instantaneous state of charge (SOC) for the corresponding calculated open circuit voltage (OCV).

6. The BMS of claim 5, further comprising:

a transceiver configured to wirelessly communicate between the electric vehicle and a power grid expert system (PGES).

7. The BMS of claim 6, further comprising:

a client portal display device, comprising a processor;

an application that is executable on the processor for performing steps comprising;

calculating a time averaged rate of battery discharge from the measuring of the current over the period of time from the battery;

determining a projected range of the electric vehicle by using the SOC and a maximum capacity of the battery, and the time averaged rate of battery discharge;

acquiring a cost per kWh of charge at a charging station; and

displaying on the client portal display device one or more data selected from the group consisting of;

the SOC of the electric vehicle;

the projected range of the electric vehicle;

the cost per kWh of charge at a location of the charging station; and

the location of the charging station.

8. The BMS of claim 5, wherein said programming performs steps comprising:

determining a maximum capacity of the battery through calculations performed on the measured current and voltage over a period of time from the battery; and

tracking over time the maximum capacity of the battery as a state of health of the battery.

9. The BMS of claim 5, wherein the batter state of charge (SOC) is determined without using a schematic model of the battery.

10. The BMS of claim 5, wherein said programming performs steps comprising:

determining a time-averaged current draw by averaging the measured current over the period of time from the battery;

determining a time-averaged electric vehicle speed by averaging a speed of the electric vehicle over another period of time;

determining a remaining battery capacity by multiplying the state of charge (SOC) by a maximum capacity of the battery; and

determining a remaining range by dividing the remaining battery capacity by the time-averaged current draw, and multiplying by a time-averaged electric vehicle speed.

11. The BMS of claim 10, wherein said programming performs steps comprising:

transmitting from the electric vehicle the remaining range to a client portal; and

optionally displaying on the client portal the remaining range.

12. The BMS of claim 11, wherein the transmitting step is either direct, or via a relayed transmission through a power grid expert system.

13. The BMS of claim 11, wherein said client portal comprises:

a display device; and

a transceiver configured to wirelessly communicate with the electric vehicle and the power grid expert system (PGES).

14. The BMS of claim 6, wherein the power grid expert system (PGES) comprises:

a charging station configured for charging a battery in an electric vehicle from an electric power grid;

said charging station optionally including a grid tie inverter configured for backfilling power from an electric vehicle connected to the charging station into the electric power grid;

a PGES computer; and

a program that is executable on the PGES computer for performing steps comprising;

selectively controlling a charging of the battery in the electric vehicle by the charging station;

or

if the charging station has the grid tie inverter, then;

selectively controlling a discharging of the battery for backfilling power to the electric power grid from the battery in the electric vehicle.

15. The BMS of claim 13, wherein the power grid expert system (PGES) comprises:

a charging station configured for charging a battery in an electric vehicle from an electric power grid;

said charging station optionally including a grid tie inverter configured for backfilling power from an electric vehicle connected to the charging station into the electric power grid;

a PGES computer; and

a program that is executable on the PGES computer for performing steps comprising;

selectively controlling a charging of the battery in the electric vehicle by the charging station;

or

if the charging station has the grid tie inverter, then;

selectively controlling a discharging of the battery for backfilling power to the electric power grid from the battery in the electric vehicle.

16. An electric vehicle apparatus, comprising:

(a) an electric vehicle;

(b) a battery in the electric vehicle;

(c) a computerized control system in the electric vehicle;

(d) a voltage sensor, connected to the computerized control system, for measuring battery voltage;

(e) a current sensor, connected to the computerized control system, for measuring battery current;

(f) computerized control system programming executable on the computerized control system for performing steps comprising;

mapping a reference open circuit voltage (ROCV) to a reference state of charge (RSOC) of the battery through a discharge cycle to produce a ROCV-RSOC mapping;

measuring a current and a voltage over a period of time from the battery;

calculating an open circuit voltage (OCV) of the battery under a load; and

using the ROCV-RSOC mapping for determining an instantaneous state of charge (SOC) for the corresponding calculated open circuit voltage (OCV); and

(g) a transceiver configured for wireless communication between the computerized control system and a power grid expert system (PGES).

17. The apparatus of claim 16, wherein said power grid expert system (PGES) comprises:

a charging station configured for charging the battery in the electric vehicle from an electric power grid;

said charging station optionally including a grid tie inverter configured for backfilling power from an electric vehicle connected to the charging station into the electric power grid;

a computer; and

programming executable on the computer for selectively controlling charging the battery in an electric vehicle connected to the charging station and,

if the grid tie inverter is present, then

backfilling power to the power grid from the battery in an electric vehicle connected to the charging station.

18. The apparatus of claim 16, further comprising:

a client portal display device comprising a processor;

a programming executable on the processor for performing steps comprising;

determining a projected range of the electric vehicle;

acquiring a cost per kWh of charge at a charging station; and

displaying on the client portal display device one or more data selected from the group consisting of;

state of charge of the electric vehicle;

projected range of the electric vehicle; and

cost per kWh of charge at a charging station.

19. The apparatus of claim 16, wherein said computerized control system programming executable performs steps comprising:

determining a time-averaged current draw by averaging the current over the period of time from the battery;

determining a time-averaged electric vehicle speed by averaging the electric vehicle speed over another period of time;

determining a remaining battery capacity by multiplying the state of charge (SOC) by a maximum capacity of the battery; and

determining a remaining range by dividing the remaining battery capacity by the time-averaged current draw, and multiplying by the time-averaged electric vehicle speed.