Harmonic cancellation unit and harmonic cancellation method

摘要

PROBLEM TO BE SOLVED: To provide a harmonic erasure unit for harmonic erasure in a power-based device, and a method of harmonic erasure.SOLUTION: In the case where a first total harmonic distortion THD in a grid current of a power-based device is greater than a predefined value, harmonic erasure is executed by first determining a dominant harmonic having a maximum amplitude among a plurality of harmonics in a waveform from a power grid. Further, phase locked loop PLL-based correction is executed in that waveform, a PLL corrected waveform is obtained, and a second THD is determined in that PLL corrected waveform. In the case where the second THD is greater than the predefined value, iteration-based correction relating to a predefined correction value is executed on a plurality of harmonics other than the dominant harmonic, and an iteration-based corrected waveform for harmonic erasure in the power-based device is obtained.SELECTED DRAWING: Figure 5