| 摘要 |
PURPOSE:To reduce a higher harmonic current by selecting a power supply voltage phase and an output voltage phase in a manner wherein harmful higher harmonics are canceled each other between a number of cycloconverters. CONSTITUTION:A 2-multiplex polyphase cycloconverter is constituted of unit cycloconverters 11-32, alternately anti-parallel connecting a separately-excited converter and a self-excited converter, and input transformers 41-43, driving a load 5 of AC motor or the like. Each of two sets of these cycloconverters 11-32 sets its input voltage phase different 30 deg. by connection of the input transformers 41-43. By the phase thus selected, the fifth and seventh higher harmonic components are reduced as compared with when no phase difference is generated in the input voltage (phase difference 0). Further selecting an output voltage to a phase difference of 180 deg. is equivalent to replacing the unit cycloconverter 12A with the self-excited converter while the other converter 12B with the separately-excited converter. |
