| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and a system for accurately measuring a secondary time constant of an induction electric motor for driving an elevator. <P>SOLUTION: First of all, when making a car travel at a constant speed in a state of loading a weight on the car when estimating that a load of the induction electric motor becomes 0 when making the car travel at the constant speed, an electric current command value is switched to 0 in a control circuit for controlling an electric power converter for supplying electric power to the induction electric motor, and zero current control is started. Assuming an output voltage value of the control circuit at this time as Vstart, a target voltage value Vend of 1/e of the Vstart is set as the output voltage value being a reference of the finish of time constant measurement. Next, a value of a counter is increased until the output voltage value of the control circuit reaches target voltage Vend. Time corresponding to a count value when the output voltage value reaches the target voltage Vend, is determined as a secondary time constant of the induction electric motor. <P>COPYRIGHT: (C)2011,JPO&INPIT |
