Running EtherCat on none supported EtherCat servo drivers using PWM

I need help answering some EtherCat questions; I plan on using Beckhoff ek1100. However, the servo drivers I have support PWM only and not EtherCAT. Is there a slave device I can use to help generate the PWM needed to run the drives? Or what options do I can. 

beckhoff has some servo control modules, but they literally cost more than buying a delta b3 full kit. So probably not worth while.

There are stand alone modules made by people other than  Beckhoff.
one is the Rtelligent RTEC1616 which has 4 PWM outputs

Thank you. I will look into the driver's cost

Wow this may be what I just need, Thank you so much for that information