| 摘要 |
PROBLEM TO BE SOLVED: To realize stable control at constant control of V/f, by preventing oscillation of torque and currents, and a step out which occurs when a load changes rapidly. SOLUTION: A controller is constituted where control is conducted, causing voltages to be applied to the windings of a permanent-magnet synchronous motor 7 made to be approximately proportional to their frequency, by a power converter such as an inverter, etc. The controller is provided with a current detector which detects the currents of at least two phases flowing in the windings and a converting means 8, a coordinate transforming means 9 which separates a detected current into two-axis current components which are parallel and perpendicular with respect to a voltage vector applied to the motor 7, a filter 10, a linear amplifier 11, and an adding means 12 for making it feed back a frequency correction Δf* generated on the basis of the current component, parallel to the voltage vector to a frequency command f* of an applied voltage of the motor to be given to an inverter 6. |
