High-frequency signal injection (HFI) is widely used for sensorless motor control but has mostly been studied in machines with high saliency ratios. In outer-rotor permanent magnet-assisted synchronous reluctance motors (OR-PMaSynRMs), the external rotor extends the magnetic flux path and increases the symmetry of the reluctance barriers. This reduces the inductance difference between the dq-axes, thereby lowering the saliency and weakening the effectiveness of conventional HFI methods in position estimation. Hence, advanced sensorless control strategies are required for such motors. This study presents an adaptive HFI control strategy that combines frequency, amplitude and filter adaptation with a proposed voltage limiting mechanism. The algorithm has been experimentally implemented for the first time on an OR-PMaSynRM. The results confirm the applicability of the HFI technique to low-saliency motors and its ability to provide reliable and robust sensorless control.