| 摘要 |
PROBLEM TO BE SOLVED: To make a continuous control of an inverter possible from the start-up to all the outputs and thereby reduce a change in torque by adjusting, by means of a mode change processing means, the carrier synchronization in a non- synchronous modulation mode when the measured time from the non-synchronous modulation mode to a preliminarily determined switching point comes in a specified range. SOLUTION: Signals from a master controller 2 for controlling powering, braking, and the like are converted into digital signals by means of an input/ output interface 3. The speed and the current are controlled by a host processing means 4 based on the output from the input/output interface 3 and then PWM pulse signals 15-20 which become the bases of U-W phases are generated according to an inverter output frequency command 13 and an output voltage command 14. A pulse mode judging means judges whether the pulse mode is dipolar, unipolar, or pulse modulation and then output a switching signal based on the judgement result. When the pulse mode is switched from non-synchronous dipolar to synchronous unipolar, the switching signal is output after the completion of mode change processing is confirmed. By this method, a change in voltage and torque near the switching point can be made small. |
