what is the best speed Observer for my SynRM (motor) that may be impemented in simulink model ?

i have non lineair model in Simulink, i tried to synthetise a non lineair observer for speed parametre ,where sensoless control of the machine (synchronouse reluctance motor) is requiered till now i have medeled the motor then started with flux estimator but doesnt work i will be so thankfull if someone could help !