| 摘要 |
PURPOSE:To stabilize a voltage at a capacitor on a d.c. current side, by constituting a device in such way that an output current detector including the d.c. component of a voltage type inverter is provided in a current feedback system, and the control of an output current is performed by the detected value of the detector. CONSTITUTION:A current detector 7A detects the currents of (a) phase and (b) phase of the voltage type inverter 4 with 'Hall element' current transformers Ha and Hc. The detected outputs of the current transformers Ha and Hc are taken out by a two phase-three phase converter 8 as the currents ia-ic of phases (a)-(c), and are used as the detecting current of a current feedback control system. In the above constitution, d.c. current components are superimposed on the detecting signals of the current transformers Ha and Hc in addition to a.c. current components, and the d.c. current component is also supplied to the current feedback control system. In such way, correction of zero d.c. current is applied on the output current of the inverter 4, and the unbalancing property of the voltage at the capacitor on the d.c. side is eliminated. Also, deviated magnetism in a reactor 3, or an inverter output transformer is prevented from being generated.
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