Abstract

In an induction motor controller, for the amount equivalent to the secondary interlinkage flux computed by use of a component of lag of first order based on the search coil voltage or the primary voltage of the induction motor, an error with respect to the actual secondary interlinkage flux is increased in a low-speed range. However, since an estimated amount equivalent to the secondary interlinkage flux computed based on the estimated amount of the secondary interlinkage flux is also attended with the same error with respect to the secondary interlinkage flux, when the former is substracted from the latter, there only remains a term concerning the speed estimation error, which enables an estimation of the speed to be conducted also in the low-speed range. Furthermore, since the time constant of the component associated with the lag of first order is varied depending on the primary angular frequency, dumping is fixedly developed for the amount equivalent to the secondary interlinkage flux, and as a result, the speed identification characteristic is fixed regardless of the high-speed and low-speed operations of the induction motor.

Other References

• Okuyama et al., "A High Performance Speed Control Scheme of Induction Motor Without Speed and Voltage Sensors," IEEE Industry Application Society Annual Meeting, pp. 106-11