| 摘要 |
PROBLEM TO BE SOLVED: To reduce the amount of overcurrent resisted by an inverter during the rushing-in of load. SOLUTION: This control method suppresses the influences of an excess current produced by the rushing in of a load, a decrease in wire voltage, and the advance of phase in a self-excited inverter which is connected to an ac feeder to compensate reactive power and to deliver effective power. In this case, a load current A is full-wave rectified 11, and a rectified output B is peak held 12 so that a peak value is attenuated with a predetermined time constant; then the rectified output B is sampled and held at O points (0 deg., 180 deg.) of the load current, and a comparator 17 compares the current full-wave rectified value B with a value C that is sampled and held half a cycle earlier than the current value, and if the value is equal to or greater than a set value, Iset, it is regarded as indicating the detection E of the rushing-in of the load, and then the voltage and phase of the inverter are corrected respectively by an inverter voltage lowering signal indicating a predetermined correction and by a phase advance signal. |
