| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the distortion of an output voltage by weakening motor magnetic flux so that the output voltage does not exceed a limit value obtained in real time in accordance with the magnitude of an input voltage of a direct converter, and to prevent the generation of a torque ripple and the rotation irregularity of a motor. <P>SOLUTION: This AC-AC direct converter such as a matrix converter drives the motor by converting an AC voltage to an AC voltage having an arbitrary magnitude and frequency by using a bi-directional semiconductor switch. The AC-AC direct converter comprises a detection means 5 that detects the magnitude of the input voltage of the matrix converter 2 and an operation means 6; and a d-axis voltage command operation means 7 that operates an output voltage limit value that limits the output voltage of the matrix converter 2 into a range where the input voltage can be PWM-controlled, and operates an output voltage command value of the matrix converter 2 so as to reduce the motor magnetic flux on the basis of the limit value. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
