PMSMs Torque Estimation Using Pulsating HF Current Injection

Torque estimation in permanent magnet synchronous machines (PMSMs) is highly desirable in many applications. Torque produced by a PMSM depends on the permanent magnets' ( PM) flux and dq-axis inductances. Consequently, precise knowledge of these parameters is required for proper torque estimation. This paper proposes the use of a high frequency (HF) signal for PM flux and dq-axis inductances estimation. The HF signals will be injected in the stator via inverter superposed on top of the fundamental excitation. Appealing properties of this method include operation in real time, without interference with the normal operation of the machine and independent of machine working condition.(1)