| 摘要 |
The purpose of the invention is to provide a power conversion device capable of supplying a constant voltage to a load against a wide range of voltage variation of an AC power supply while avoiding size increase, cost increase, and efficiency loss and of suppressing the surge voltage of a bidirectional switching element. The device is constituted by a step up/down chopper unit (10), an inverter unit (20a), a rectifier unit (30a), first to third voltage detection means (61 to 63), and a drive control unit (71). A voltage adjusting means (74) of the drive control unit (71) generates, according to the voltage detection value detected by the voltage detection means (61), a control signal for controlling the voltage effective value of a capacitor (3) to be constant. The switching elements of the step up/down chopper unit (10) and inverter unit (20a) are driven by the control signal, and the voltage effective value of the capacitor (3) is thereby controlled to be constant. The rectifier unit (30a) allows charge storage elements (21, 22) to absorb the energy stored in a reactor (4) when bidirectional switching elements (5, 6) are off, thereby suppressing surge voltage. |
