| 摘要 |
PURPOSE:To eliminate error due to integrating operation and to realize flux operation and speed inference by providing a rotary coordinates converting section for determining the primary current on a rotary coordinates based on the phase angle between the primary current and primary voltage of a motor and a section for operating the secondary flux. CONSTITUTION:A voltage type vector operating section 3 performs vector operation on a torque current command iT* and a flux current command iO* so that they do not interfere with each other thus obtaining primary voltages V1alpha, V1beta on a rotary coordinates. A slip angular frequency operating section 4 determines a slip angular frequency omegas based on a current command iT* and a secondary time constant tau2(=L2/R2). Rotor angular frequencies omegar are then added to obtain a power supply angular frequency omegao and an integrator 5 determines a phase angle theta. When the speed of a motor 9 is inferred, primary currents Iu, Iv are detected through current transformers 101, 102 and subjected to phase conversion from three-phase to two-phase through a rotary coordinates converting section 11 thus obtaining primary currents i1alpha, i1beta, on the rotary coordinates. A secondary #12beta is then determined at an operating section 12. |
