| 摘要 |
PURPOSE:To positively prevent noise by providing a corresponding series resonance circuit on the outside of a converter and an inverter constituting VVVF power source of an elevator depending on the generation of high frequency components contributing to noise. CONSTITUTION:Using VVVF obtained by forward-converting a commercial three-phase power source 1 by an converter 2 and by backward converting it by an inverter 4, an A.C. motor 5 is driven by a command from a control circuit 900 to lift and lower a cage 8. Series resonance circuits 30, 40, 50 which are turned on and off by BPF 100 and transistors Tr 34, 44, 54, are provided on the output side of the converter 2. Series resonance circuits 60-62, 70-72, and 80-82 which are turned on and off by BPF 200-400 and Tr 604-606, 704-706 and 804-806 are connected between respective phases on the output side of the inverter 4. When the control circuit 900 detects high frequency components, Tr of the resonance circuit corresponding to the high frequency is selected to be turned on. |
