Sensorless control of permanent magnet synchronous machines reduces both volume and overall cost, because no mechanical position sensor is required. At zero speed and in the lower speed range, saliency-based methods of sensorless rotor position estimation place special demands on the machine's electromagnetic design. A machine design considering the typical criteria does not necessarily meet these demands. In particular, load-dependent saturation effects often cause critical operating points with vanishingly low saliency, not permitting a reliable rotor position estimation. Up to now, these design criteria have barely been investigated yet. By means of modified rotor laminations or short-circuited rotor coils increasing high-frequency saliency, the quality of sensorless rotor position estimation can be improved specifically. Both approaches consider the boundary conditions, i.e. an unchanged torque density of the motor and small increase of losses. The rotor coils are especially suitable for smaller motors with surface magnets, for lack of space not tolerating the use of buried magnets or additional flux barriers. With the appropriate design, the additional losses caused by the damping of non-synchronous field components are negligibly small.