| 摘要 |
PURPOSE:To prevent a commutation failure from occurring even is a rotating speed signal contains an error by shifting the commutation margin angle in phase to a value larger than the value during an ordinary operation when the rotating speed of a commutatorless motor falls within the prescribed set range and further in accelerated state. CONSTITUTION:A commutation reference signal from a commutation reference signal generator 1 which is outputted by synthesizing a pulse signal from a position detector (not shown) is converted by a rotating speed signal generator 2 into a rotating speed signal fPG. A control leading angle is determined by a commutation command oscillator 4 which inputs the output of a commutation margin angle controller 5 through a commutation margin angle detector 3 which inputs the signal fPG and the signal fPG, and the firing of a frequency converter 7 is controlled through a gate unit 6. The signal fPG is also inputted to a rotating speed detector 8 and an acceleration detector 9, and is controlled to output the prescribed control leading angle only when the error of the signal fPG from the detector 8 is lower than the rotating speed detected to be unable to become a cause of commutation failure and recognized to be during acceleration from the result detected by the acceleration detector 9. |
