| 摘要 |
PURPOSE:To automatically estimate a variation in resistance, to hold a torque and a speed controlling accuracy high for a short time while a variation in temperature of a motor is small after starting and to solve an insufficient starting torque by applying a DC voltage at the time of starting in a short time and measuring a variation in a flowing current. CONSTITUTION:At the time of driving a three-phase induction motor 2, a switch 14 is closed at a moment after t1 time from when it is started, and a starting current I is input to a resistance estimating calculator 15. A starting current In of an output of a reference value memory 16 at a reference temperature, a primary resistance R1n and a secondary resistance R2n are input to the calculator 15, which estimates a primary resistance R1 and a secondary resistance R2, and outputs them to a state variable calculator 5. Accordingly, resistance values to be used for the calculator 5 become the outputs R1, R2 of the calculator 15 instead of the R1n, R2n by the operation after the t1 time from when a start signal ST becomes '1'. Thus, calculation errors of a speed and the torque, are reduced, and an insufficient starting torque can be alleviated. |
