This paper discusses the encoderless control of a permanent magnet synchronous machine fed by an extra low DC bus voltage that operates in the low-speed range. It focuses on optimizing the high-frequency voltage injections parameters necessary to estimate the electrical position of the rotor. The encoderless control method adopted is the pulsating carrier voltage injection, however the optimization algorithm can be applied to other methods as well. The quality of the estimated position is influenced by the amplitude of the injected voltages, which also affect the disturbance of the machine torque. Therefore, the objective of this study is to find a balance between the quality of the estimated position and the injection-related intrusion. This paper proposes an experimental approach for determining the optimal injection level which allows accurate estimation of the electrical position and reduce the torque disturbance. It also provides the experimental validation results of the optimal injection voltage implementation.