I need help with generated V/hz curve.
My motor is a 95Vrms 4poles 50Hz 1430rpm 2,2Kw and my DC bus is 120V.
On wiki saids:
In my case is:fweak is the frequency at which the full possible voltage is generated. It is also the point of the highest motor power. Beyond fweak torque will decrease to the square of frequency and thus power will decrease linear with frequency.
For illustration we will assume a bus voltage of 500V and a 4-pole (p=2) motor with a nominal speed of n=1450rpm@f=50Hz and 230V. With 500V DC an AC voltage of 500/1.41=355V can be generated.
With our illustration motor fweak=(355 V/230 V) * 50 Hz = 77 Hz. fweak can be configured lower than that resulting in more torque at the low end.
fweak=(85 V/95 V) * 50 Hz = 44 Hz ; Is this correct?
In my case is:fslipmin/fslipmax is the slip frequency at which the motor is run at minimum/maximum throttle. fslipmin is set to the motors optimal slip frequency which can be deduced from the nameplate. fslipmin=f-p*n/60. With our illustration motor fslipmin=50-2*1450/60=1.66Hz. fslipmax can be set as high as breakdown torque which is not found on the nameplate. So its best found experimental starting with 2*fslipmin. If set too high the motor will start to rock violently on startup, possibly tripping the over current limit.
fslipmin=50-2*1450/50=1.66Hz ; Same value at example, is this correct?
fslipmax=3.32Hz ?
What´s best curve for a electric car? It must rise to 50Hz and then constant up to say 200Hz?fconst, Frequency where slip frequency is derated to form a constant power region. Only has an effect when < fweak
help here too please.fslipconstmax, Slip frequency at maximum throttle and fconst.
sorry for my english and thanks to all of you.
