6 Replies Latest reply on Jan 26, 2016 5:46 PM by dougw

# Regenerative braking

i am currently working on my diploma project..i have decided to make an regenerative braking working model

concept is to use a dc motor to drive a wheel using belt drive. cutting the power supply of motor while braking.

while braking; the motor will keep rotating in the same direction with wheel until its stopped completely. the plan is to use this rotation of motor to generate electricity.

my questions are;

is it possible to generate electricity with same direction of rotation of motor as it was while power supply was on. if yes; then how?

it will be helpful if anyone can tell me which circuits i will need to make.

• ###### Re: Regenerative braking

Hi Salman,

If this is going to be for a demonstration you will get better results if you put the wheel right on the motor shaft as you will not have to deal with energy loses that would be present in a belted system with two axles. When the power is removed from the proper type motor the energy in the inertia of the spinning wheel and the translational kinetic energy of the vehicle that continues to spin the motor produces electricity of the same polarity as before. If the electrical energy from the motor is then put into a load this creates increased magnetic resistance between the rotor and stator of the motor and acts to slow the motor and vehicle. This is the braking part. If the load that we put on the motor is used to recharge the battery then we are regenerating the battery and the system can be considered a regenerative braking system. Do not expect to get more than a small % of what you put into the system back. You will have to build a good system and take good measurements to demonstrate the concept.

John

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• ###### Re: Regenerative braking

There is an interesting thread here

http://forum.arduino.cc/index.php?topic=164421.0

How many watts do you want to drive?

• ###### Re: Regenerative braking

How Regenerative Braking Works

Article shows details. You could use a spring to capture and release energy as a demo.

C

• ###### Re: Regenerative braking

i am currently working on my diploma project

My first question is What is the Diploma in ??

I would have thought that lifting a small weight, that once released will then generate the energy to show "regenerative braking".

When ON it will slow down the weight, and OFF the weight will effectively freefall.

Mark

• ###### Re: Regenerative braking

The motor will pump up the DC link voltage through the diodes in your H Bridge; the voltage will rise and you have to detect it. A typical H Bridge will have a brake circuit that dissipates into a resistor. As a test, you should have plenty of inertia in your mechanical system to store energy to be returned to the electrical system.

Does an automotive scheme re-charge the battery rather than dissipate in a resistor? That would make sense.

• ###### Re: Regenerative braking

Connect the motor shaft directly to a second DC motor (which is used as a generator).

The electrical load on the generator will dictate how much braking is applied to the motor.

Switch a load onto the generator when you want to brake.

The load can be resistors (incandescent light bulbs make good demonstration loads) or a battery to recover the charge, but if a battery is used, the current and voltage to it would need to be measured.

Add a big flywheel to the motor shaft to increase the regeneration energy.

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