Speed Sensorless Vector Controller Using High Frequency Injection in Induction Motors

摘要

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed sensorless vector controller using high frequency injection in an induction motor. In the related art, in the case of the first startup, the response to the load torque is late, so that the startup fails in many cases, and the estimation fails even when the torque of the rated load changes. There was a problem in applying the load. Therefore, the present invention multiplies the position and velocity observer in the speed sensorless controller using the high frequency injection, and the high frequency current, the cosine function and the sine function, respectively, which decomposes the high frequency detection current having the polarity information into the q-axis and d-axis components, respectively. A heterodyne process unit 22A for outputting an error signal obtained through a new heterodyne process for obtaining a difference of the multiplied value, and a low pass for outputting a filtering error signal obtained by performing low pass filtering on the error signal obtained above. A filter controller 22C, an observer controller 22C that receives the filtering error signal outputted from the filter, calculates a flux speed estimate through integrator and gain control, and performs gain control on slip speed of an induction motor based on the flux speed estimate. A speed compensator 22E for outputting a magnetic flux compensation compensation estimated value by adding a value, and the magnetic flux compensation Configured as an integrator (22D) by integration of the setpoint to obtain the magnetic flux position estimation, in the sudden change of the load and accurately estimate the speed and position of the magnetic flux, is a transient state to improve the torque response always enables a successful start-up.