Inverter-fed induction machines in traction applications — Extraction of equivalent circuit parameters from synchronous speed and locked rotor tests

While permanent magnet motors are increasingly being utilized in high performance and high power-dense drives, the induction motor is still almost universal for new electric train drives and gaining popularity in vehicular drives. This is on top of their traditional role as an industrial drive motor for pumps and fans and also their use in servos. The key to good control of these motors is accurate parameter estimation. Running light and locked rotor tests are the well-established methods of testing the motor. This paper describes proposed procedures so the equivalent circuit parameters can be estimated for a wider range of voltage and frequency values. These can be a function of frequency and voltage which is often neglected. Mathematics procedures and experimental results are presented.