ripple current problem

[boydli]

Hi all,
I meet a problem on the ripple current of DC brush motor.
First,our customer require that the RMS ripple current is between a maximum value and a minimum value. Second,the sum power of foundermental frequency has a minimum value(ratio,compared to the whole power). At last,the sum power of foundermental and first harmonic frequency has a minimum value(ratio,compared to the whole power).
I made many motor samples with different poles and different slots. Some meet all the requirement,some are failed. Till now I do not know why this happened.How should I do improvements on the failed sample?
Thanks very much.
Boydli

 

[blacksea]

Do you have current ripple with power amp PWM switching frequency? The current ripple is function of switching frequency and armature inductance.