Self-commissioning of electrical parameters for PMSM in sensorless drives

PMSM applications in high-performance control, with or without sensors, involve well self-tuning of the controllers and observers to machine parameters with off/on-line identifications for “plug-in” controllers. This paper proposed self-commissioning methods to automatic identify the PMSM electrical parameters (stator resistance, dq-inductances and PM flux) in sensorless drives, sometimes the rotor is allowed to move. No added hardware or off-line manipulation is required. An observer-based equivalent stator resistance identification, including the inverter resistance and dead-time, is developed at standstill by using two dc current injection levels in phase a and the corresponding stator voltage references. A new dq-inductance identification strategy using HF voltage injection at standstill is proposed with two cascaded observers: i) observer of the current-produced stator flux (without PM flux) - robust to dc offset and PM flux, and then ii) observer of the dq-inductances based on the error of the current-produced stator flux. The PM flux is estimated at constant speed with V/f control in two steps: the stator flux without integration, and the rotor position based on the active flux are estimated in αβ stator reference, and then the PM flux is computed in dq rotor reference. The identification methods are validated by simulation results with good results.