| 摘要 |
PROBLEM TO BE SOLVED: To provide an active filter which can suppress voltage variation of a DC capacitor during load variation while effectively compensating higher harmonic and can be downsized.SOLUTION: The active filter includes: first derivation means 32 for dividing a period from predetermined time before present time up to the present time into a plurality of sections and deriving a fundamental wave component from one or both of an effective current component and a reactive current component of a load current sampled in each divided first section; and second derivation means 33a for dividing the section from the predetermined time before the present time up to the present time into sections smaller than the number of first sections and deriving an effective current component reference value or a reactive current component reference value of a load current sampled in each divided second section by performing weighted average calculation of one or both of an effective current component and a reactive current component of the sampled load current, to mutually subtract outputs of the first and second derivation means 32, 33a and output a compensated current command value. |
