Vector control device for an AC motor

摘要

A vector control device for an alternating current electric motor having an LC filter circuit comprising a reactance coil (2) and a capacitor (3) on one side of the DC power supply (1) and a inverter (4) that converts a voltage through the capacitor, which is the voltage (Efc) of the capacitor, to an AC voltage that has any frequency, comprising: a vector controller (30) to execute a vector control on the motor (6) electric alternating current according to a setpoint (Id *, Iq *) of current or a setpoint (Tm *) of torque; and a damping controller (40) for calculating a damping operation amount (DAMPCN) to suppress the variation of the capacitor voltage (Efc), operate with the current setpoint (Id *, Iq *) or the setpoint (Tm * ) of torque of the vector controller (30) based on the amount (DAMPCN) of calculated damping operation and controlling the inverter (4) so that the current flowing in the inverter (4) varies so that its variation with respect to the variation of the voltage (Efc) of the capacitor, in which the damping controller (40) sets as the amount (DAMPCN) of damping operation the value of a signal obtained by calculating the square of the rate (Efcfp) of variation of the voltage (Efc) of the capacitor under the electric-powered operation of the electric motor (6) of alternating current, and establishes as the amount (DAMPCN) of damping operation the value of a signal obtained by calculating the square of a signal (Efcn) that is obtained by inverting the phase of the rate (Efcfp) of variation of the voltage (Efc) of the capacitor under the regenerative operation of the electric motor (6) of alternating current, and in which the damping controller (40) limits the upper and lower limits of the amount (DAMPCN) of damping operation by means of a limiter (49).