| 摘要 |
<P>PROBLEM TO BE SOLVED: To generate a sine wave-shaped AC output signal synchronizing with an AC input signal having a higher harmonic voltage. <P>SOLUTION: A phased locked loop for processing an instantaneous value is configured of a first phase difference detecting circuit 1 and a first since wave signal generating circuit 2. A frequency difference detecting circuit 4 calculates a frequency difference between an AC input signal and an AC output signal from the instantaneous values of a first sine wave signal outputted from the first since wave signal generating circuit 2 and a second sine wave signal outputted from a second since wave signal generating circuit 9. A second phase difference detecting circuit 3 calculates a phase difference between the first since wave signal and the second sine wave signal. An adding circuit 5 adds the phase difference detection signal to the frequency difference detection signal, and a frequency change rate limiter circuit 8 inputs the output of the adding circuit 5, and sets the frequency change rate of the second sine wave signal to a fixed value or less, and outputs an instruction signal for synchronizing the sine wave signal to the AC input signal to the second sine wave signal generating circuit 9. <P>COPYRIGHT: (C)2004,JPO |
