| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a portable power unit which enables the thyristor constituting a cyclone converter to surely continue commutation and keep stable action, even at a low power factor load, by preventing the cyclone converter from becoming control disabled and unable to perform self arc extinction. <P>SOLUTION: This portable power unit subtracts (Fig. 5(c) and (d)) the output value of targeted waves 2 from the output value of detected waves, using the targeted waves being delayed by a fixed time X equivalent to the delay of the phase of itself as the objective waves 2, and compares the subtracted wave having shown this subtracted output value with the output value of the objective waves 2 at the same time so as to detect a signal geared to power factor; a power factor detection circuit 19 adjusts the approximate effective value of an approximate effective value calculating circuit 8, based on this detected signal, and lowers the approximate effective value of the approximate effective value calculating circuit 8, especially at a low power factor load so as to lower the output voltage, thereby adjusting it. <P>COPYRIGHT: (C)2003,JPO</p> |
