An analysis of the benefits of signal injection for low-speed sensorless control of induction motors

Pascal Combes (1) , François Malrait (2) , Philippe Martin (1) , Pierre Rouchon (1, 3)

1 CAS - Centre Automatique et Systèmes
2 Schneider Toshiba Inverter Europe [Pacy-sur-Eure]
3 QUANTIC - QUANTum Information Circuits

We analyze why low-speed sensorless control of the IM is intrinsically difficult, and what is gained by signal injection. The explanation relies on the control-theoretic concept of observability applied to a general model of the saturated IM. We show that the IM is not observable when the stator speed is zero in the absence of signal injection, but that observability is restored thanks to signal injection and magnetic saturation. The analysis also reveals that existing sensorless algorithms based on signal injection may perform poorly for some IMs under particular operating conditions. The approach is illustrated by simulations and experimental data.

Domaines: Automatique / Robotique

Pascal Combes, François Malrait, Philippe Martin, Pierre Rouchon. An analysis of the benefits of signal injection for low-speed sensorless control of induction motors. International Symposium on Power Electronics, Electrical Drives, Automation and Motion 2016, Jun 2016, Capri, Italy. pp.721 - 727, ⟨10.1109/SPEEDAM.2016.7525835⟩. ⟨hal-01486948⟩