Flux and Position Observer of Permanent Magnet Synchronous Motors with Relaxed Persistency of Excitation Conditions∗

In this paper we propose a flux and position observer for permanent magnet synchronous motors when voltages, currents and rotor speed are available for measurement. We prove that this observer converges under weaker assumptions than the classical persistence of excitation condition. Simulations confirm the eficacy of the proposed observer and show that it can cope with imprecision in rotor speed measurement, which allows to use an estimator when the speed cannot be measured directly.