An order tracking analysis consists in post processing vibroacoustic calculations or measurements to extract the acoustic noise or vibration levels of some excitation frequencies proportional to speed (the so-called excitation electrical or mechanical orders).
Application to e-NVH
Noise and vibrations due to electromagnetic excitations are characterized by strong tonalities due to the discrete nature of magnetic force spectrum. Depending on the electrical machine topology, these excitations may be directly proportional to speed. This is the case of Permanent Magnet Synchronous Machines independently of the load, or Induction Machines at no-load (null slip) for slotting excitations.
PWM excitations may not be directly proportional to speed (e.g. in case of asynchronous switching frequency). However PWM lines may be proportional to the speed around a DC frequency offset (e.g. 5000 Hz +/30fR, where fR is the mechanical rotation frequency).
Application to MANATEE
MANATEE software dedicated to the electromagnetic and acoustic simulation of electric motors includes automated order tracking analysis which can be acessed through plot commands. The following commands are available: