Designing a VFD for 1HP induction motor.
Designing a VFD for 1HP induction motor.
(OP)
I have been tasked with designing a variable speed drive for an induction motor. What is the required (recommended) ripple for the DC voltage? This will determine my capacitor. What happens if I operate with more ripple?
I understand I need to maintain constant air-gap flux with constant voltage / frequency ratio. I don’t know why! Any good (basic) papers that cover this topic?
I understand I need to maintain constant air-gap flux with constant voltage / frequency ratio. I don’t know why! Any good (basic) papers that cover this topic?





RE: Designing a VFD for 1HP induction motor.
volts/hz too high may cause overheating of the core due to saturation.
volts/hz too low will cause the torque vs slip curve to decrease... if mild this will only cause slip to increase slightly (for given freqeuncy and load), but if severe this may create the potential for a stall condition.
RE: Designing a VFD for 1HP induction motor.
RE: Designing a VFD for 1HP induction motor.
RE: Designing a VFD for 1HP induction motor.
But large ripple on the DC-Link voltage can lead to oszillations of the motor. See:
Kalker, T.; Ackva A.; Jansen, U.: "Novel Digital Controller for Induction Machines Considering Inverter Switching Times and a Fluctuating DC-Link Voltage", EPE 1991, Firenze (Conference Proceedings), p. 2-058 to 2-063
RE: Designing a VFD for 1HP induction motor.
In regard to electricuwe's response, any idea how to get a hold of the paper "Novel Digital Controller for Induction Machines Considering Inverter Switching Times and a Fluctuating DC-Link Voltage"?
RE: Designing a VFD for 1HP induction motor.
RE: Designing a VFD for 1HP induction motor.
Search engines did lead me to lots of info on European Conference on Power Electronic and Applications. I wan't able to find the paper (only the abstract). It would be great if you could forward me a copy (dpulis@chamberlain.com). Thanks once again!
Any chance you will be at APEC next week? They have a couple of papers on motors. I will be there for a few.