| 摘要 |
The invention relates to an electronically commutated motor (20) comprising a first connection (46) for connecting to a positive pole of a direct-voltage source (47) and a second connection (50) for connecting to a negative pole (50) of said direct-voltage source (47), further comprising a stator having a stator winding arrangement, which has at least one phase winding (26), a permanently magnetic rotor (28), which influences the form of the current (i1, i1') in the stator winding arrangement (26) during operation by means of the rotation of said rotor, a detecting arrangement (64), which is designed to detect and digitize at intervals a current supplied to the motor (20) from the direct-voltage source (47), wherein said current flows from the first connection (46) through the detecting arrangement (64) to the second connection (50) during operation, wherein the absolute value of the motor current (i1, i1') during operation has different sections as follows: a first section (113), subsequently referred to as current back, which rises to a maximum (114) starting from the commutation (118, 118'); a second section (115), subsequently referred to as current saddle, which falls to a minimum (116) starting from the maximum (114); a third section (117), subsequently referred to as current tail, which follows the current saddle (115); and a program-controlled computer (36), which is designed to carry out the following steps: a) the position of the current back (113) is determined from the digitized current values; b) the position of the current saddle (115) is determined from the digitized current values; c) a current value (118; 118') at which a commutation process should begin is determined on the basis of the detected position of the current back (113) and the current saddle (115); and d) if the absolute value of the motor current (i1, i1') reaches or exceeds said current value (118; 118'), the commutation process is initiated. |
