20-11-2012, 04:24 PM
Regenerative Braking
regen_braking_presentation.ppt (Size: 6.01 MB / Downloads: 691)
What is Regenerative Braking?
Conventional braking systems convert kinetic energy into heat, usually via friction.
This wastes a great deal of energy!
Regenerative braking systems reclaim and storing the kinetic energy in a reusable manner
Many modern electric drive vehicles including electric locomotives and HEVs have regenerative braking systems
How Regen Braking WorksPart 1: The Mechanical Aspect
Vehicle has forward momentum
The wheels are coupled to the rotors of electric traction motors in an EV
Instead of a current being applied to the motor to turn the rotors, the rotors are turned by the wheels of the EV
The rotors experience opposing torque as current is induced in the motor coils
This opposing torque slows the vehicle
The generated electrical energy is stored
Brake Control Circuitry
Complex electronic circuits that handle braking functions
Coordinates motor and friction brakes under a wide range of situations
The controller will take the following parameters into account and determines how the vehicle will brake
Speed of vehicle
Driver input (pedals)
Storage medium state-of-charge
Routes and regulates generated power
Depending on the desired output, the brake controller must be able to supply vehicle batteries or capacitors with the proper polarity, current, and voltage for safe charging (depends on battery state of charge)
Mechanical Methods
Hydraulic Regenerative Braking
Slows the vehicle by compressing gas and storing it in an accumulator
Pressure is used to assist the engine upon forward acceleration
Potentially more efficient than electric regenerative brake systems