POWER-FACTOR IMPROVEMENT TYPE THREE-PHASE CONVERTER DEVICE

摘要

PURPOSE:To control the improvement in the power factor of input currents without switching loss by connecting the series circuit of a resonance CHOKE coil and a second switching element in parallel with a first switching element and on-off controlling the first switching element while carrying out zero-volt switching. CONSTITUTION:Voltage applied to a smoothing capacitor Cd is applied to a first capacitor Cr under the off state of a first switching element Tr, a second switching element Tc is turned on under this state, to make current flow through a resonance choke coil Lc. The zero-volt switching of the first switching element Tr is made possible when the applied voltage of the first capacitor Cr is brought to zero, and the zero-volt switching of the second switching element Tc is made possible when the first switching element Tr is turned on and the secound switching element Tc is turned off. Accordingly, the first switching element Tr is on-off controlled, thus smoothly conducting control of an improvement in a power factor.