초록 ▼

A vector control system for an induction motor driven by a power converter which generates three phase ac currents containing harmonics. In the system, an exciting current command value and a torque current command value in a rotating magnetic field coordinate system are applied, induction motor pri

A vector control system for an induction motor driven by a power converter which generates three phase ac currents containing harmonics. In the system, an exciting current command value and a torque current command value in a rotating magnetic field coordinate system are applied, induction motor primary currents in a stator coordinate system is detected at a period which is the same or integral multiple of that of the harmonic components by integration operation, the detected value of the integrated primary currents is subjected to definite integration over the same time interval as the period thereof thereby detecting fundamental wave components of the primary currents without the harmonic components, the fundamental wave components are transformed in the form of rotating magnetic field coordinate system thereby detecting an exciting current component and a torque current component, a deviation between the exciting current command value and the detected actual exciting current component and a deviation between the torque current command value and the detected actual torque current component are detected respectively, and producing and applying to the power converter three phase ac voltage command values in the stator coordinate system tending to reduce the deviations to zero.

대표청구항 ▼

A vector control method for a three-phase ac induction motor comprising the steps of: applying an exciting current command value and a torque current command value in a rotating magnetic field coordinate system; detecting an actual exciting current value and torque current value; detecting a deviati

A vector control method for a three-phase ac induction motor comprising the steps of: applying an exciting current command value and a torque current command value in a rotating magnetic field coordinate system; detecting an actual exciting current value and torque current value; detecting a deviation between said exciting current command value and said detected exciting current value and a deviation between said torque current command value and said detected actual torque current value; producing three phase ac voltage command values in a stator coordinate system tending to reduce said deviations to zero; and determining voltages and a frequency for driving said induction motor in accordance with said three phase ac voltage command values; said actual exciting current value and torque current value detecting step further comprising, integrating a value of each of selected two phase ac inputs of three phase ac inputs of said induction motor and then sampling the integrated values at a predetermined period; subjecting each of said sampled values of the integrated two phase ac inputs to a definite integration at said predetermined period; and transforming said definite integrated values respectively to an actual exciting current value and torque current value in a rotating magnetic field coordinate system.