| 摘要 |
PURPOSE:To detect circulation currents continuously and control the reactive power accurately by a method wherein the circulation currents are controlled by a value which an absolute value of load currents is subtracted from the sum of the detecting values of the output currents of a positive group converter and a negative group converter. CONSTITUTION:When a phase advancing capacitor is connected to a power source terminal of the circulation current type cyclo-converter and the circulation currents of the converter are controlled, the output currents of the positive group converter SS-P and the negative group converter SS-N are detected by means of detectors CTP, CTN, and added by means of an adder A1. Load currents are detected by means of a detector CTL, added with a value of the adder A1 through an absolute value circuit ABS and an inversion circuit INV, and increased half by means of an amplifier K0 to obtain the circulation currents, and the converter is controlled so that the currents are equalized with the reference value. Thus, the circulation currents can continuously be detected, the slippage of a change-over point is removed, and the converter can accurately be controlled. |
