| 摘要 |
PURPOSE:To improve the precision of magnetic flux estimation and speed con trol, by fluctuating the value of magnetic flux at the same time as DC voltage fluctuation. CONSTITUTION:DC voltage fed to an inverter 4 is divided with voltage-dividing resistors 10a and 10b, and the divided voltage is converted to a digital value by an A/D converter 11. The ratio of the digital value namely the detected value of the DC voltage to rated DC voltage is found by an amplifier circuit 12. Then, the output of the amplifier circuit 12 is multiplied by a voltage com mand value V' from a control circuit 8, with a multiplier circuit 13, and the input of the multiplied result to a magnetic flux arithmetic circuit 9 is provided. As a result, the value of magnetic flux is fluctuated with the fluctuation of the DC voltage, and the estimation precision of the magnetic flux of an induc tion motor 2 is improved. |
