| 摘要 |
A method for controlling an electric motor (3) by using the PWM technique; the control method includes the steps of: applying to the clamps (38) of the electric motor (3) an electric voltage (Vm(t)) varying in time, which displays a square waveform and consists of a sequence of pulses having a uniform wave period and a variable amplitude; adjusting the average value of the electric voltage (Vm(t)) applied to the clamps (38) of the electric motor (3) by varying the amplitude of the pulses of the electric voltage (Vm(t)); determining, in the case of a variation of the amplitude of the pulses, the overall required amplitude variation; subdividing the overall required amplitude variation in a determined number of partial variations, the overall sum of which is equivalent to the overall required amplitude variation; and gradually varying the amplitude of the pulses of the electric voltage (Vm(t)) by applying in a sequence a corresponding partial variation to each pulse, so that the difference between the amplitude of a pulse and the amplitude of a following pulse is equivalent to the corresponding partial variation. |
