I am driving a BLDC motor using trapezoidal commutation table. But i am finding a dip in voltage for a short duration on the positive side of the phases R, Y, B. Similarly there is a rise in voltage during the negative cycle. I am not able to understand the reasons. Any advice?

 

Post the hook up and circuit used.
How are you sensing commutation point.
Max.

 

Sorry for the late reply. I do not have access to the schematic diagram. But i am doing commutation using Hall sensors. I am checking the waveform at the R, Y, B terminals of the motor. I am observing this behavior on every hall change. I want to know while switching the Mosfets for every hall change will there be any fluctuation on the phase line voltage? Why does it happen?