Start-up procedure for brushless DC motors having position sensors with angular resolution lower than the resolution of the driving system

摘要

A start-up routine is provided for a multiphase brushless DC motor having one or more rotor position sensors insufficient to provide for an angular resolution as high as the angular resolution of the synchronized driving system of the motor. The start-up routine includes setting at least an angular check zone having a certain arc length angularly correlated to the one or more rotor position sensors, assuming a certain initial rest position of the rotor, and exciting for fixed time intervals the phase windings in a sequence for rotating the rotor toward an angular position next to the initial position. This routing is performed in the desired direction while masking the signals from the one or more rotor position sensors for a preestablished masking time. The step of exciting for fixed time intervals is repeated until verifying that the excited phases are those commanding advancement of the rotor toward the angular check zone, or a change of state of the signals of the one or more rotor position sensors if the masking time has elapsed. The start-up routine further includes associating to each code of the position sensors a new angular check zone to be reached by repeating the sequence of operations starting from step of exciting.