Power conversion device

Abstract

According to the present invention, an inverter circuit 10 includes a plurality of flying capacitors C1-C4 and converts DC voltage supplied from a DC power supply 2 to AC voltage. A filter circuit 20 makes the waveform of the output voltage of the inverter circuit 10 approximate a sine wave. An overcurrent protection circuit 60 supplies a block signal for turning off a plurality of switching elements Q1-Q24 to a drive circuit 40 when an overcurrent is detected. When at least one of a voltage abnormality of any of the plurality of flying capacitors C1-C4 and an abrupt variation of the output voltage of this power conversion device 1 occurs, a voltage other than the positive voltage of the DC power supply 2, the negative voltage of the DC power supply 2, and zero voltage is restricted to be output from the inverter circuit 10.

Description

technical field [0001] The present disclosure relates to power conversion devices that convert DC power to AC power. Background technique [0002] Efficient power conversion and compact design are desired for power conditioners connected to solar cells, storage batteries, fuel cells, and the like. Since the multilevel power conversion device can reduce the voltage applied to the switching element, it is possible to reduce switching loss and realize efficient power conversion. As a typical implementation method of a multilevel power converter, there is a flying capacitor method (for example, refer to Patent Document 1). [0003] MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors: Metal-Oxide-Semiconductor Field-Effect Transistors) with a withstand voltage of 600 V, 300 V, and 150 V are often used as switching elements for inverters used in power conditioners. Generally, when the withstand voltage of the switching element is low, the conduction loss and the switchin...

AI Technical Summary

Problems solved by technology

[0006] If a momentary voltage drop occurs, it is easy to generate overcurrent

Images