| 摘要 |
PURPOSE:To compensate the reactive power efficiently by a method wherein a selection circuit is added, the cyclo-conver, an angle of lag of phase thereof is the nearest to 90 deg., is selected among the cyclo-converters feeding power to load every phase, and the circulation currents are controlled. CONSTITUTION:A phase advancing capacitor C is connected to a power source line BUS, and the circulation current type cyclo-converters CC-U, CC-V and CC-W are formed every phase to polyphase load and power is supplied while the phase angle and the circulation currents are controlled by means of phase control circuits PHC- U-W. The cyclo-converter, the phase angle of control thereof is the nearest to 90 deg., is selected among each cyclo-converter and the circulation currents are controlled by adding the selection circuit SLC to the reactive power control circuit. Thus, the variation of reactive power is prevented without flowing wasteful circulation currents, and the power-factor of fundamental harmonics can efficiently be controlled to maintain 100% at all times. |
