| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor drive device capable of preventing excessive vibration when passing through a critical speed while suppressing increase in cost.SOLUTION: A motor drive device comprises: an Id and Iq setting unit 402 setting current commands Id and Iq in a d-q axis rotation coordinate system on the basis of a current command I; and a PWM signal generation unit generating a PWM control signal for on-off controlling a plurality of switching elements on the basis of the current commands Id and Iq and a calculated magnetic pole electric angle &thetas;. In addition, the Id and Iq setting unit 402 sets the current command Id to a negative value in the case that a rotation speed ω is in a critical speed section (ω1≤ω≤ω2). When the current command Id is set to the negative value, a magnetic field is generated in a direction of cancelling the magnetic flux by a permanent magnet of a motor rotor 11, and magnetic eccentricity is reduced, so that swirling in the critical speed section is reduced. |
