| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem conventionally associated with PFC converters, that a converter output at power-factor correction(PFC) controlling is set to a value sufficiently higher than the maximum value of input supply voltage with a margin, for maintaining PFC control corresponding to supply voltage fluctuations, and if the fluctuation in input supply voltage is large and its maximum value exceeds the output voltage command for PFC, with the possibility of stoppage of the power-factor correcting operation. SOLUTION: The input supply voltage is detected continuously, and control is thereby performed with the output voltage commands for PFC being always higher than the minimum voltage (maximum voltage of input supply voltage), at which PFC actuates. By performing such a control, in this way, power-factor correcting operation can be performed to cope a wide range of fluctuations in input supply voltage. In addition, since it is unnecessary to needlessly increase the output voltage commands for PFC, PFC control with less loss is made possible.
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