This invention provides a three-phase single-stage multi-cavity parallel power conversion device, comprising: an AC / DC conversion circuit, the input port of which is connected to three-phase
alternating current; the output port of the AC / DC conversion circuit including a first terminal, a second terminal, and a third terminal; and a DC / DC conversion circuit including at least three
rectifier units, wherein the first input terminal of each
rectifier unit is connected to the first terminal via a first switch, the first input terminal of each
rectifier unit is connected to the second terminal via a second switch, and the first input terminal of each rectifier unit is connected to the third terminal via a third switch; the output ports of the plurality of rectifier units are connected in parallel. This invention enables
power factor correction and output current or
voltage regulation, improving the reliability, conversion efficiency, and
power density of the power conversion device.