# higher back-EMF voltage like input voltage in Brushless DC Motor?

Currently I am working on simulation model for the non-control Brushless DC motor in MATLAB/Simulink environment. BLDC parameters are from the paper via IEEE online library. For now, I am not able to understand why I have higher back-EMF voltages in each phase like the input voltage. I know, it is not easy question, because you don't see my MATLAB/Simulink model, but I can send it to you by email. For example, if the input voltage is 60V (+- 30V for each phase) then I have (+- 33-34V) back-EMF voltages for each phase.

-
The coils magnetic flux is collapsing causing a the higher back EMF - this is why you always include a flyback diode whenever a (large) coil is used. –  Paul Sullivan Aug 28 '12 at 20:14
Thank you for your answer. Could you help me how can I put a flyback diode to the model? Thank you. –  user11860 Aug 29 '12 at 12:53
Google 'flyback diode example' –  Paul Sullivan Aug 29 '12 at 15:41