| 摘要 |
PURPOSE:To provide a measure against the situation where AC output voltage or reactive power output can not be increased only through control at the side of power inverter, by increasing DC voltage at the side of power rectifier. CONSTITUTION:Power fed from an AC system 1 is rectified through a transformer 2 and an external commutated rectifier 3, then inverted through a self- commutated power inverter 13 and fed through a transformer 14 to an AC system 15. Voltage and current of the AC system 15 are detected respectively through transformers 19, 20, then active and reactive powers are operated and compared with set values. Thereafter, control angle theta and phase psi are varied by an operating unit 40 through a reactive power operating unit 21 and a constant power controller 38 so as to control the power inverter 13. When the capacity of the power inverter reaches to its limit, the phase psi reaches a lower limit which is lower than a referential value psim, and thereby a limiter 52 produces an output which is added to DC voltage setting value Eref of the rectifier 3. Consequently, DC voltage of the rectifier 3 increases. |
