D- and Q-Axis Inductance Estimation and Self-Sensing Condition Monitoring Using 45$^\circ$ Angle High-Frequency Injection

This article proposes a high-frequency injection based dq-inductance estimation technique for synchronous machines. The d- and q-axis inductance is estimated using a single HFI between d and q axes, i.e., 45° injection angle. The d- and q-axis incremental inductance variation over four quadrants dq-plane operating condition is evaluated. The proposed technique can operate in real-time without a controlled position or velocity from the load side. Neither previous knowledge of machine parameters nor computationally expensive regression processes are required. The proposed technique can be used to evaluate the sensitivity of inductive saliency based self-sensing to determine preferable self-sensing operating conditions for permanent magnet synchronous machines.