| 摘要 |
PURPOSE:To realize direct detection of operated first degree flux frequency by delivering a pulse, for indicating an operated flux frequency on a switching table, upon gaining an access to a flux declination area thereby outputting a pulse signal directly in digital mode. CONSTITUTION:An inverter section 3 feeds an AC three-phase voltage to a three-phase induction motor 2 according to the switching pattern of switching elements Sa0-Sc1. Instantaneous current and voltage of the motor 2 are then fed to an inverter control circuit 5. An operating circuit 6 operates the magnitude, angle an instantaneous torque of first degree interlinkage flux vector in the motor 2 based on the instantaneous current and voltage detected through a current/voltage sensor 4. A selection circuit 7 then gains an access to a switching table 8 such that the error is confined within a predetermined range based on the target values of first degree interlinkage flux and torque command of the motor 2 provided from a system computer 9 thus selecting a switching voltage pattern to be set. |
