NEUTRAL POINT CLAMPING TYPE POWER CONVERTER

摘要

PURPOSE: To reduce the losses of the snubber circuits of second and third switching elements by providing a snubber circuit constituted by connecting a fifth snubber resistor and snubber capacitor in series between a neutral output terminal and the connecting point of the second and third switching elements. ;CONSTITUTION: No overvoltage is applied across a switching element SCU2, because the energy of a wiring inductance is absorbed by snubber capacitors SCU2 and SCU3. The capacitor SCU2 which has absorbed the energy of the wiring inductance discharges the energy through a snubber resistor SRU2, DC power source Vd1, and the capacitor SCU2 and, when the voltage of the capacitor SCU2 becomes equal to that of the power source Vd1, the capacitor SCU2 terminates the discharge. Since the capacitor SCU2 only discharges the amount equal to the energy of the wiring inductance, all of the electric charges in the capacitor SCU2 are not consumed by the snubber resistor SRU2 differently from the conventional snubber circuit in which the electric charges are completely consumed by a snubber resistor. Therefore, the loss of the snubber circuit can be reduced remarkably.;COPYRIGHT: (C)1996,JPO