Magnetic flux weakening control method for electric motor driving electric power converter

摘要

PROBLEM TO BE SOLVED: To suppress the fluctuation of the rotating speed of an electric motor even if the output fluctuation is generated frequently and rapidly in the electric motor operated with a field current reduced to decrease magnetic noise. SOLUTION: A circuit is configured so that a magnetic flux command outputted from a magnetic flux-weakening operation circuit 10 maintains a previous value, even if the output of an electric motor changes from high to low by inputting the torque operation value of the electric motor being driven by a power conversion device to the magnetic flux-weakening operation circuit 10 via a delay timer processing circuit 21. Therefore, the amount of drop in the rotating speed of the electric motor can be suppressed since the field current has not decreased even if the output of the electric motor changes rapidly from low to high within a short time.