Battery powered electric vehicle and electrical supply system

• US 5,642,270 A
• Filed: 01/28/1994
• Issued: 06/24/1997
• Est. Priority Date: 08/01/1991
• Status: Expired due to Fees

• Current Assignee: Wavedriver Limited (PowerGen Corp.)
• Original Assignee: Wavedriver Limited (PowerGen Corp.)
• Inventors: Green, Ross Martin, Kellaway, Michael John
• Primary Examiner(s): KRISHNAN, ADITYA
• Application Number:
  US08/182,190
• Time in Patent Office: 1,243 Days
• Field of Search: 320/12, 320/61, 320/5, 363/21, 363/63
• US Class Current: 363/17
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 2220/54 Windings for different functions
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 50/62 charged by low-power generators primarily intended to support the batteries, e.g. range extenders
• CPC Class Codes: B60L 53/11 DC charging controlled by the charging station, e.g. mode 4
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/22 Constructional details or arrangements of charging converters specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/24 Using the vehicle's propulsion converter for charging
• CPC Class Codes: B60L 53/62 in response to charging parameters, e.g. current, voltage or electrical charge
• CPC Class Codes: B60L 53/64 Optimising energy costs, e.g. responding to electricity rates
• 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: B60L 58/12 : responding to state of charge [SoC]
• CPC Class Codes: B60L 58/21 : having the same nominal voltage
• CPC Class Codes: B60L 58/25 : by controlling the electric load
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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 10/72 : Electric energy management in electromobility
• 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 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

A charging system for a battery powered electric vehicle operates bidirectionally for charging the battery or for supplying power back to the utility grid at any selected power factor so that load leveling may be effected. A communications link between the utility and the charging system carries control signals and a control system associated with the charging system is responsive to the signals for controlling the charging rate and direction.

Claims

1. In a battery powered electric vehicle, a system for controlling power transfer with a power distribution network for charging and discharging the battery when connected thereto comprising:

power transfer means for passing electric power bi-directionally between the battery and the power distribution network;

communication means operatively coupled between the power distribution network and the power transfer means for providing control signals indicative of at least one of a selected power factor, power level and harmonics content to the power transfer means in accordance with the supply and demand on said power distribution network; and

control means responsive to the control signals and operatively coupled to the power transfer means for controlling the power passing between the battery and the power distribution network.

2. A system according to claim 1, which is integral with an on-board vehicle electric traction drive system.

3. A system according to claim 1, wherein the battery charging/supply system includes a number of semiconductor switches.

4. A system according to claim 1 including a timing means for controlling power transfer at selected times.

5. A vehicle according to claim 1, further including a state-of-charge estimator to control the maximum charge and discharge states of the battery.

6. A system according to claim 1 wherein the communication means comprises a channel separate from the power distribution network.

7. A system according to claim 1 wherein the communication means includes power lines of the power distribution network for carrying the control signals superimposed thereon.

8. A system according to claim 1 including an AC traction motor;

a pulse width modulated (PWM) converter having first and second ports controllable to convert a DC electrical signal, fed from the battery to the first port, into an AC drive signal for the motor fed out from the second port;

an AC input port; and

switch means connected to the second port, for switching the second port between the traction motor and AC input port, whereby the AC input port, on connection to an AC source can be connected to the converter to charge the battery.

9. A system according to claim 8, which further comprises plural DC link capacitors for sourcing and sinking high frequency current pulses that result from the operation of the power converter, the PWM converter including an unidirectional self-commutating semiconductor switches (Q₁ -Q₆) with anti-parallel diodes (D₁ -D₆), the switches being arranged in a full-wave bridge configuration.

10. A drive system according to claim 9, including a microprocessor based controller for generating drive pulses to provide gating signals to the switches (Q₁ -Q₆).

11. A system according to claim 8, including an electromechanical changeover switch comprising a pair of mechanically interlocked contactors which allow connection of the PWM converter to either the AC traction motor or the AC utility supply inlet port.

12. A system according to claim 11, wherein the position of the changeover switch is controlled by the microprocessor.

13. A system according to claim 8, including an interlock for inhibiting changeover occurring while the vehicle or the traction motor is in motion.

14. A system according to claim 8, wherein the battery is of lead-acid, sodium sulphur, sodium nickel chloride or other type suitable for vehicle traction.

15. A system according to claim 8, including apparatus for providing an auxiliary DC voltage supply for vehicle equipment, from the PWM controlled converter, including means for offsetting a neutral point of a multi-phase supply by offsetting the PWM sequences for each inverter output pole.

16. A system according to claim 8, including means for enabling the battery to be charged through the PWM converter.

17. A system according to claim 16, wherein said means comprises a switching device positioned in series between at least one of the battery and the converter and between the converter and the charging AC supply.

18. A system according to claim 16, wherein an auxiliary converter is provided, in parallel with the main converter, to enable charging of the battery independently of the main converter.

20. A system according to claim 7 wherein the communication means includes at least one of a radio, cable and fiberoptic link.

21. A system according to claim 20 wherein the communication means includes billing means.

23. A system according to claim 1 wherein the power transfer means includes a three phase circuit.

24. A system according to claim 1 wherein a plurality of said battery powered vehicles, each having a charging system and batteries at various charging states are coupled to the power distribution network and the control signals are selected for each vehicle such that the plurality of charging systems cooperate to provide load leveling of the power distribution network.

19. A system for controlling power transfer between a battery powered electric vehicle and a power distribution network comprising:

power transfer means for passing electric power bi-directionally between the battery and the power distribution network for charging and discharging the battery;

communication means operatively coupled between the power distribution network and the power transfer means for providing control signals of a selected vectorial relationship to the power transfer means in accordance with supply and demand on said power distribution network said vectorial relationship including at least one of a power level, power factor and harmonic content; and

control means responsive to the control signals operatively coupled to the power transfer means for controlling the power passing between the battery and the power distribution network in accordance with said vectorial relationship.

22. A system according to claim 19 wherein the communication means includes a ripple generator.

25. A charging system for controlling power transfer between a battery powered electric vehicle and a utility power grid subject to supply and demand comprising:

circuit means on the vehicle for passing electric power between the battery and the power distribution network;

communication means operatively associated with the power grid for providing control signals to the circuit means in accordance with the supply and demand on said power distribution network; and

control means responsive to the control signals and operatively coupled to the power transfer means for controlling at least one of a power factor, power level and harmonics content of the power passing between the battery and the power distribution network.

26. A system for charging a battery representing a sensible load from energy supplied by a power grid and for discharging the battery to supply energy back to the grid comprising:

circuit means for bi-directionally passing power between the battery and the grid in accordance with supply and demand on said grid;

control means operatively coupled to the circuit means for controlling charging and discharging of the battery in accordance with control signals selectively representing real and reactive components of the power to be transferred; and

communication means between the power grid and the control means for carrying said control signals to said control means.