| 摘要 |
PURPOSE:To remove a side band by a method wherein a relative firing angle of a thyristor bridge connected in series is controlled according to an output current phase, and pulsations of a fundamental wave reactive power and a fundamental wave component of an input current are controlled to be zero. CONSTITUTION:A three-phase source 1 is connected to the thyristor bridge 3 through a transformer 2 and supplies a 3-phase power to a load 4. A current command value 16 and a detected current value obtained from sine-wave function generator 12 are compared with each other to be fed to a current control circuit 18 and further, the output of the circuit 18 is supplied to a relative firing angle control circuit 24 to control phase control circuits 20A1, 20A2, an output voltage phase angle on AP1 side of the bridge 3 being led by phi and the output voltage phase angle on AP2 side being made lag by phi and the values of phi are changed in proportion to a specific function according to the output current phase angle. Therefore, the pulsations of the fundamental wave reactive power and the fundamental wave current on the input side of the converting device can be arrested and also, instabilization of the system can be prevented. |
