摘要 |
An electrical motor comprises a stator 1 and a rotor 2 , the stator 1 having poles 3 facing circumferential surfaces of the rotor 2 so that the stator 1 forms a magnetic circuit with the rotor 2 . The stator 1 further has stator windings 5 grouped into two or more phase windings A, B, which phase windings are separately energisable to induce stator magnetic fields which interact with magnetic fields associated with the rotor 2 . A voltage across a stator phase winding is detected by voltage detecting means. Processing means 18 to 20 is provided for determining from one or more voltage measurements the rotor flux linking said stator phase winding, or a value which is a function of the rotor flux linkage, when the excitation current in said stator phase winding is at a known point in its cyclic variation chosen to substantially eliminate from the rotor flux or said function inductive and/or resistive contributions, and for determining from the rotor flux linkage or said function thereof the load angle of the motor. |