This paper deals with stator-flux-oriented control of permanent-magnet (PM) synchronous motors and synchronous reluctance motors (SyRMs). The variables to be controlled are the stator-flux magnitude and the torque-producing current component, whose references are easy to calculate. However, the dynamics of these variables are nonlinear and coupled, potentially compromising the control performance. We propose an exact input-output feedback linearization structure and a systematic design procedure for the stator-flux-oriented control method in order to improve the control performance. The proposed controller is evaluated by means of experiments using a 6.7-kW SyRM drive and a 2.2-kW interior PM synchronous motor drive.