Described is a method of determining a speed of a synchronous motor having a rotor and a stator having windings. The method comprises sensing currents in the windings of the stator while the rotor is rotating and transforming the currents into a two-dimensional (2D) coordinate system using an alpha-beta (α-β) transformation, wherein the alpha-beta (α-β) transformation is a Clarke transformation, the 2D coordinate system having an α-axis and a β-axis. The method includes determining a rotor angle θ from an arc tangent (A tan) of a ratio of a current iα in the α-axis to a current iβ in the β-axis and determining a speed of the motor from the rotor angle θ.