| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem wherein though a power converter interlocking with a power distribution system having no transformer has been researched and developed by connecting a semiconductor elements in series for an output of higher voltage, since the output voltage is in pulse on the power converter, a harmonic component of output current is large enough to generate a magnetomotive force fluctuation due to the reactor of the power distribution system, resulting in oscillation of the reactor for generating noise. <P>SOLUTION: By making a frequency of noise to be higher than or equal to a maximum frequency within an audible band of a human being, noises generated from a power converter are suppressed. In order to attain this, the phase of switching drive carrier wave of unit converters are mutually shifted by a predetermined value between the unit converters, so that the frequency of an output current harmonic component which is a source of noise exceeds the maximum frequency of audible band of a human being. The frequency of driving carrier wave of the unit converters is required to be set to satisfy an equation: f<SB>carrier</SB>>f<SB>audibility_max</SB>÷N. <P>COPYRIGHT: (C)2011,JPO&INPIT |
