| 摘要 |
Provided is a direct-type power conversion device employing a boost chopper, in which the average value or the effective value of the current flowing through an inductor of the boost chopper is reduced. When a rectifying duty (dr), a discharge duty (dc), a voltage (Vc) between both ends of a capacitor (34), and a rectified voltage (Vrec) of an AC voltage (Vin) are introduced, a virtual DC link voltage (Vdc) in an inverter (6) is expressed by dc·Vc + dr·Vrec. The discharge duty (dc) is a time ratio during which a switch (41) is conducted. The rectifying duty (dr) has a value obtained by subtracting the discharge duty (dc) and a zero voltage duty (dz) from 1. The zero voltage duty (dz) is a time ratio during which the inverter (6) employs a zero voltage vector regardless of the magnitude of the voltage output by the inverter (6). The capacitor (34) is charged by a boost chopper (3) in a part of the period during which the virtual DC link voltage (Vdc) is larger than the rectified voltage (Vrec). |
