SynRM Sensorless Torque Estimation Using High Frequency Signal Injection

Precise output torque control is one of the major concerns in synchronous reluctance machines. Torque measurement systems are expensive, require extra room, add weight, can introduce resonances into the system, and their performance can be compromised due to electromagnetic interference. As an alternative, torque can be estimated. However, torque estimation methods are sensitive to machine parameters variation. Injection of a high frequency (HF) signal in the stator via inverter has been shown to be a viable option for online machine parameters estimation in permanent magnet synchronous machines (PMSMs). This paper proposes a torque estimation method for synchronous reluctance machines (SynRMs) using a HF signal.1