CONTROLLING METHOD OF TORQUE OF VECTOR-CONTROLLED INDUCTION MOTOR

摘要

PURPOSE:To improve the precision in a steady-state torque control by a method wherein the relationship between a higher torque command and an output torque estimated value is obtained beforehand by using a T type equivalent circuit, the higher torque command is converted into the output torque estimated value by using this relationship and the torque control is executed by using this output estimated value. CONSTITUTION:A current command outputted from a vector control computation part is inputted as a primary current input of a T type equivalent circuit in a torque command conversion part 1, an exciting current and a secondary current are calculated from the number of revolutions and a slip frequency of a three-phase induction motor at that time and an output torque estimated value T*' is obtained. The relationship between this output torque estimated value T* and a higher torque command T* is stored in the forms of tables 111, 112, 113,... 11n in regard to the cases of the numbers N1, N2, N3,... Nn of revolutions of the induction motor. When the higher torque command T* is given, switchover is made to the pertinent table by a switch controller 13 according to the number of revolutions of the motor at that time, the output torque estimated value T* corresponding thereto is read and conversion is executed.