METHOD FOR CONTROLLING THE COMMUTATION IN AN ELECTRONICALLY COMMUTATED MOTOR, AND AN ELECTRONICALLY COMMUTATED MOTOR FOR CARRYING OUT SAID METHOD

摘要

A method is disclosed for controlling the commutation in an electronically commutated motor ( 20 ) which comprises a stator having at least one phase ( 24, 26 ), and a permanent-magnet rotor ( 22 ), and with which a current limiter ( 36, 58 ) and a controller ( 18 ) for regulating a motor variable are associated. The current limiter ( 36, 58 ) serves to limit the current (I) in the at least one phase ( 24, 26 ) to a setpoint value. The regulation by means of the controller ( 18 ) is accomplished by modifying the distance in time (W) between switching on (t 1 ) and switching off (t 2 ) of the current (i 1 , i 2 ) in the at least one phase. In this method, the setpoint value to which the current limiter limits the current (i 1 , i 2 ) in the relevant phase is modifiable. It is modified substantially as a function of a ratio of two times (W/T), namely as a function of the ratio of the distance in time (W) between switching on (t 1 ) and switching off (t 2 ) of the current (i 1 , i 2 ) in the relevant phase ( 24, 26 ) to the time period (T) required by the rotor, at the instantaneous rotation speed, to rotate through a specified rotation angle. A decrease in noise at low rotation speeds is thereby made possible.