Fast On-line Inductance Estimation for Interior Permanent Magnet Synchronous Machines Based on the Modified Square-wave Injection

This paper describes a technique for on-line inductance estimation for an interior permanent magnet synchronous machine (IPMSM) based on a modified square wave voltage injection in the d and q axes. The inductances of an IPMSM can be estimated within each pulse width modulation (PWM) cycle without the knowledge of other parameters, such as the flux linkage, the stator resistance or even the rotor speed. What is more, it is also faster and need fewer computing resources compare with other recursive techniques. Simulation results under different scenarios show that the proposed method can accurately track the inductances not only during steady states, but also during transients.