In this paper, a new method is proposed for the real-time estimation of the full parameters of a permanent magnet synchronous motor (PMSM) that is based on the stator current ripple model. By introducing the stator current ripple model together with the known two state equations for the d- and q-axes currents, we resolve the rank deficiency problem, thus enabling real-time full parameter estimation even in the steady state. A signal processing technique for removing adverse effects from noises and uncertainties existing in the stator current ripple measurement is also presented. The efficacy of the proposed method is verified by simulation on a 15-kW PMSM, and both the proposed and conventional methods are compared.