An ideal frequency inverter is modeled by using a VfController and a three-phase SignalVoltage.
Frequency is raised by a ramp, causing the induction machine with squirrel cage to start,
and accelerate inertias. At time tStep
a load step is applied.
Simulate for 1.5 seconds and plot (versus time):
currentQuasiRMSSensor.I
: stator current RMSaimc.wMechanical
: machine speedaimc.tauElectrical
: machine torquefs
: stator frequencyfr
: rotor frequencys
: slipCompare with transient models IMC_Inverter (Electrical.Machines) and IMC_Inverter (FundamentalWave). Note that electrical transients are neglected, but mechanical transients are taken into account.
By setting the stator resistance Rs = 0
, comparing quasistatic points of operation for different stator frequencies fs
,
it can be seen that
fs ≤ fNominal
rotor frequency fr
is constant, if the load torque is constant,f ≥ fNominal
slip is constant,
if load torque is adapted according to tau = tauNominal*fNominal/f
.Default machine parameters are used.