| 摘要 |
The present invention relates to an oscillator for use in a preconditioner comprising a rectifier (1), a converter (2) receiving an input voltage (Uin) and supplying an output voltage (Uout), and a control unit (3) effecting peak current mode control. The oscillator has a switching frequency with a period (Tper) dependent on the input voltage (Uin) and the output voltage (Uout), according to the relation: <math-cwu id="MATH-US-00001"> <number>1</number> <math> <mrow> <msub> <mi>T</mi> <mi>per</mi> </msub> <mo>=</mo> <mrow> <mfrac> <mn>1</mn> <msub> <mi>k</mi> <mn>0</mn> </msub> </mfrac> <mo>it</mo> <mrow> <mrow> <mo>(</mo> <mrow> <mfrac> <mn>1</mn> <msub> <mi>U</mi> <mi>m</mi> </msub> </mfrac> <mo>+</mo> <mfrac> <mn>1</mn> <mrow> <msub> <mi>U</mi> <mi>out</mi> </msub> <mo>-</mo> <msub> <mi>U</mi> <mi>in</mi> </msub> </mrow> </mfrac> </mrow> <mo>)</mo> </mrow> <mo>.</mo> </mrow> </mrow> </mrow> </math> <mathematica-file id="MATHEMATICA-00001" file="US20030071690A1-20030417-M00001.NB"/> <image id="EMI-M00001" wi="216.027" he="18.00225" file="US20030071690A1-20030417-M00001.TIF" imf="TIFF" ti="MF"/> </math-cwu> This inventive switching frequency control scheme makes it possible to provide a converter operating in the discontinuous mode that draws a block-shaped input current.
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