Collectorless three phase D.C. motor

摘要

Collectorless (brushless) three-phase DC motor having a permanent-magnet arrangement and a three-phase winding, these being movable relative to each other, and having three position sensors which are stationary relative to the winding and controlled by the permanent-magnet arrangement to supply sensor output signals. The winding's coils are energized by current in a cyclical sequence in dependence upon the sensor output signals, the latter being offset by 120 DEG -el. one from the next. Induced coil voltages are offset by 120 DEG -el.; the coil voltages, in crossing zero, are alternately positive for at most 180 DEG -el. and negative for at most 180 DEG -el. and their sum is equal to zero for all relative positions as between the magnet arrangement and the winding. The position sensors are so arranged relative to the winding's coils that the sensors' changes-of-state substantially coincide with the zero-crossovers of the associated induced coil voltages. The winding's coils are energized via winding driver stages by means of driver voltages which either directly correspond to the sensor output signals or else are derived therefrom.