Hybrid drivetrain project: Brushless DC motor/generator query

Thread Starter


Joined Oct 19, 2009
Hello all, I am currently designing a hybrid vehicle drive system which demonstrates the principles of hybrid drive for a project (not an actual vehicle compatible system) which utilizes a brushless DC motor/generator unit to both charge a battery, and power the drive train. The system is based on the Parallel hybrid drivetrain.

I am currious though as to how I can make the unit act as a generator and then be switched to act as a motor? As the battery is connected to the unit, there is no way of stopping the battery from driving the unit as a motor instead of receiving charge?

Thanks in advance for any help.
Detailed information:

The drivetrain consists of a fixed axle, which can be hand turned to demonstrate the principal of ICE torque. A sprocket gear is to be mounted on the axle, with a chain linking to another gear attached to the motor/generator units shaft.


Joined Feb 28, 2009
What controller are you using to drive your brushless DC motor? (The controller is the box that takes information from the encoder or resolver in the motor and converts the DC from the battery to the equivalent 3 phase AC that makes the motor run.) If it has H-Bridge output for each phase, simply turn off the drive to each leg of each H-Bridge to isolate the motor from the drive. Spinning the motor by means of an external source will turn it into a 3 phase generator. Six SCRs could be set up as a 3 phase bridge to rectify the output of the motor turned generator. Proper triggering of the SCRs would be required.

Go here for more reading pleasure....... www.ecnmag.com/article-brushless-dc-motors-roll-091009.aspx
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