Regenerative braking system
Regenerative braking system
(OP)
I am very new to regenrative braking systems and wanted to do some research on.
from Internet waht I could able to grasp was regenerative braking involves the electrical motor which is turned to generator when brakes are applied and so the energy is reclaimed, but how the mechanical system works ? how much time it is needed for motor to sense the brakes are applied and motor to turn into generator ? are the brakes used are normal brakes and used for all the wheels ?
from Internet waht I could able to grasp was regenerative braking involves the electrical motor which is turned to generator when brakes are applied and so the energy is reclaimed, but how the mechanical system works ? how much time it is needed for motor to sense the brakes are applied and motor to turn into generator ? are the brakes used are normal brakes and used for all the wheels ?





RE: Regenerative braking system
http://www.epa.gov/otaq/technology/420f04024.pdf
RE: Regenerative braking system
is there any resource on internet or any book I can refere to grasp the basic mechanical aspects of regenerative braking system?
RE: Regenerative braking system
RE: Regenerative braking system
In industrial applications, the acceleration time and the deceleration time is usually easy to determine and microprocessor controlled.
In an automotive drive train application, the braking energy will be much greater than the accelerating energy for a much shorter time.
Electric regenerative braking in industrial applications is not known for being efficient. Generating and storing energy over a wide rpm and torque range is difficult. All systems have an operating voltage. When a generator rpm varies, so does the voltage output. The amperage varies with load. All the variable speed control electronic systems I have looked, at are not averaging much over 80% efficient driving a varying load over their operating speed range. I have not found any data on the efficiency of any regenerative system. In wind power the varying wind speed creates their power generation difficulty, most systems control the speed by varying the prop pitch. Some of the new systems are using power electronics, but the cost and efficiency has not proven to off set the cost of prop pitch control.
The most common application for hydraulic regenerative braking is in hydraulic elevators. Most have a hydraulic cylinder to raise the car, when letting the load down the flow pressure is diverted to accumulators. Hydraulic hybrid drives currently being developed use a swash plate pump/motor and valves to divert the flow and pressure to accumulators. Neither of these systems have great efficiencies base on the calculation I have done.
One of the greatest challenges in regenerative braking is converting low energy inputs to a higher energy level required for peek acceleration power.
For these reasons I do not think current electric or hydraulic hybrids will be a long term winners in saving energy.
In theory if all the kinetic energy could be captured and reused for reacceleration, the only power required for a vehicle is to overcome wind, and rolling resistance and climbing hills.
RE: Regenerative braking system
In this cycle approximately 1/3 of the energy supplied by the engine ends up in the brakes.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.