| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a phase synchronization method can shorten a phase synchronization time required for synchronizing an inverter output phase to the phase of a commercial power supply by adjusting an inverter output frequency within its upper limit value or lower limit value so as to follow the commercial frequency. <P>SOLUTION: When phase synchronization starts, a frequency f0 and a cycle T0 of the commercial power supply are obtained (S1), and an advancing phase difference θerr_p and a delay phase difference θerr_n are calculated (S2). Cycle numbers Nu and Nl until phase synchronization are obtained in following the advancing phase difference θerr_p at the upper limit of output frequency of an inverter and in following the delay phase difference θerr_n at the lower limit of the output frequency of the inverter (S3). The cycle number of shorter time is selected from large and small relation of the cycle numbers Nu, Nl (S4), and the phase following direction of the inverter is set at the phase advancing direction or the phase delay direction (S5, S6). <P>COPYRIGHT: (C)2010,JPO&INPIT |
