| 摘要 |
PURPOSE:To eliminate higher harmonic current component extremely, by fitting an intermediate tap on a reactor connected to the side of an AC power source, and by connecting a capacitor to the intermediate tap. CONSTITUTION:The controller of an elevator is provided with a transistor inverter 2 on the side of a power source as a power converter, and is connected to a three-phase AC power source 1 via a reactor 18. Besides, the controller is provided with the detector 5 of output voltage, a reference voltage setter 6, a voltage control amplifier 7, a three-phase sine-wave oscillator 8, and the like, and the output of the three-phase AC power source 1 is converted to specified DC voltage by the inverter 2. Then, an intermediate tap is fitted on the reactor 18, and a filter 20 with a capacitor 19 only is connected to the intermediate tap. Then, if the constants of the reactor 18 and the capacitor 19 are selected so that the resonance frequency f of the filter 20 to the modulation frequency f0 of a PWM may be f<f0, not only the modulation frequency content of the PWM but also the ripple content of the higher harmonic can be eliminated. |
