| 摘要 |
PURPOSE:To make torque ripples small by parallel operating two inverters PWM-controlled by the use of triangular carrier waves with phases differing 180 deg. from each other and by composing the output current of said inverters and supplying it to a lifting motor. CONSTITUTION:An elevator apparatus by inverter drive is equipped with a riding cage 1, a winding machine 3 for winding up a rope 2 for said cage, and a lifting motor 5; speed-current detectors 6-7; an inverter equipment 8; and an inverter controller 9. In this case, two inverter equipments 8 through PWM control using carrier waves with phases differing 180 deg. from each other are provided and the output current of said inverter equipments is composed and applied to said motor 8. Thus, ripple currents included in said output current outbutted from both inverters 8 cancel each other so as to be capable of becoming very small. |
