| 摘要 |
The present invention relates to a direct power converting apparatus in which electrostatic capacitance required by a discharge resistor is reduced. A transistor (S1) is brought into conduction when, for example, a voltage between both ends of a second clamp capacitor (C2) exceeds a predetermined reference voltage. A resistance value of a discharge resistor (R1) is smaller than a value obtained by dividing the reference voltage by the maximum value of a current flowing through the discharge resistor (R1). When the transistor (S1) is brought into conduction as a result of a voltage (Vc1) between both ends of the second clamp capacitor (C2) exceeding the predetermined reference voltage, a voltage applied to the discharge resistor (R1), which results from a regenerative current, is larger one of the voltage (Vc1) between both ends of the second clamp capacitor (C2) and a voltage drop of the discharge resistor (R1) due to the regenerative current. The voltage drop and the voltage (Vc1) between both ends are smaller than a voltage between DC power supply lines (L1, L2), whereby it is possible to reduce an electrostatic capacitance of the discharge resistor (R1). |
