REGENERATIVE BRAKING METHOD

• US 20120168242A1
• Filed: 03/23/2011
• Published: 07/05/2012
• Est. Priority Date: 03/23/2010
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Kulatunga, N. Athula
• Granted Patent: US 8,567,547 B2
• Time in Patent Office: Days
• US Class Current: 180/210
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2210/12 Buck converters
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/16 DC brushless machines
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 50/20 using propulsion power generated by humans or animals
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 7/04 for vehicles propelled by dc motors
• CPC Class Codes: B60L 7/12 for vehicles propelled by dc motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60Y 2400/114 Super-capacities
• CPC Class Codes: B62K 3/005 Recumbent-type bicycles
• CPC Class Codes: B62M 6/25 power-driven at axle parts
• CPC Class Codes: B62M 6/80 Accessories, e.g. power sources; Arrangements thereof
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A neighborhood electrical vehicle (NEV), including provisions for improved deceleration during regenerative braking, in which the vehicle momentum is converted to electrical energy stored in a capacitor bank. The capacitor bank includes alternate configurations for charging or discharging of the capacitors.

Claims

1. A vehicle, comprising:

three wheels arranged as a tricycle and supporting a seat by a frame;

a brushless DC motor mechanically coupled to at least one of the wheels;

a rechargeable battery;

an capacitor; and

an electronic controller in electrical communication with said capacitor, said battery, said motor, and said sensor, said electronic controller being operable in at least two modes;

wherein in a first mode of operation said controller receives alternating electrical power generated by said motor, rectifies the power, chops the rectified power, and provides the rectified power to said capacitor, and in a second mode of operation said controller provides power from said capacitor to said battery.

2. The vehicle of claim 1 wherein said capacitor is an electric double-layer capacitor.

3. The vehicle of claim 1 which further comprises a braking sensor providing an electrical signal corresponding to an amount of braking desired by the human operator, wherein the signal is provided to said controller, and the duty cycle of the chopped power corresponds to the electrical signal.

4. The vehicle of claim 3 wherein the signal is a pulse-width modulated alternating signal.

5. The vehicle of claim 3 wherein the frequency of the alternating signal is less than about 1000 hertz.

6. The vehicle of claim 1 wherein said capacitor has a capacity of more than about 40 farads.

7. The vehicle of claim 1 which further comprises a plurality of capacitors electrically connected in parallel.

8. The vehicle of claim 1 which further comprises a braking member movable over a range of positions by the human operator, wherein said controller applies generated power to said capacitor in relation to movement of said member within a first portion of the range.

9. The vehicle of claim 8 wherein said braking member is a hand control.

10. The vehicle of claim 8 which further comprises a friction braking assembly mechanically connected to at least one said wheel, said braking assembly being actuatable by said braking member.

11. The vehicle of claim 10 Wherein said braking assembly is not actuated by movement of said member within the first portion of the range.

12. The vehicle of claim 1 wherein said controller has a third mode of operation in which said controller provides power from said battery to said motor.

13. The vehicle of claim 1 which further comprises a pair of pedals operatively connected to a generator, said pedals being adapted and configured for a human operator to provide motive power to said generator, said generator being in electrical communication with said controller.

14. A method for operating an electric vehicle, comprising:

providing a tricycle, a braking lever movable over a range of positions, a plurality of ultracapacitors, and a seat, at least one of the wheels being coupled to an electric motor capable driving the wheel and capable of generating electricity;

generating alternating current electricity by the motor in response to placement of the lever within the range;

slowing the vehicle by said generating;

rectifying the alternating current electricity;

chopping the rectified voltage at a predetermined frequency; and

charging the ultracapacitors with the chopped voltage.

15. The method of claim 14 wherein said plurality of ultracapacitors are configured for parallel operation during said charging the ultracapacitors.

16. The method of claim 14 which further comprises electronically reconfiguring the ultracapacitors to series operation, and powering the motor with the reconfigured ultracapacitors.

17. The method of claim 14 wherein said providing including a rechargeable battery, and which further comprises charging the battery with the charged ultracapacitor.

18. The method of claim 14 wherein the motor is an electrically commutated motor.

19. The method of claim 14 which further comprises modeling the plurality of ultracapacitors in terms of an RC time constant, and establishing the predetermined frequency to be less than about four time constants.

20. The method of claim 14 which further comprises establishing a duty cycle corresponding to placement of the level within the range, wherein said charging corresponds to the duty cycle.