| 摘要 |
PURPOSE:To contrive energy saving, by providing a slip frequency correction part correcting the output command value from a slip frequency control means. CONSTITUTION:In a slip frequency correction circuit 6, a D/A converter 6a reads a current command I* in analog value and converts the current command I* into a digital signal and transfers the digital signal to a microcomputer 6b. In the microcomputer 6b, after adding the slip frequency correction value f's to a minor deviation portion DELTAf's for every sampling of the current command I*, a new f's is formed and the new f's is delivered to an inverter through an A/D converter 6c. Therefore, the f's successively moves in a fixed direction every sampling for the command I*. |
