Power conversion device

摘要

A single phase three-level power converter can include a first half bridge and a second half bridge. A half bridge operation is implemented in either the first half bridge or second half bridge when outputting a single phase alternating current voltage having an amplitude a half or less than that of a direct current input voltage, and also, by alternately switching between the bridges carrying out the half bridge operation. In certain configurations, the power converter can convert a direct current input voltage into alternating current phase voltages having three levels of potential, which are positive, negative, and intermediate voltages, by controlling on-off conditions of a plurality of switch elements, and a controller that, by supplying gate signals to the switch elements configuring the first half bridge and second half bridge, controls the related on-off conditions.

主权项

1. A power conversion device comprising:
a power converter formed of a first half bridge and a second half bridge that converts a direct current input voltage into alternating current phase voltages having three levels of potential, which are positive, negative, and intermediate voltages, by controlling on-off conditions of a plurality of switch elements; and a controller that, by supplying gate signals to the switch elements configuring the first half bridge and the second half bridge, controls the on-off conditions thereof, wherein the controller includes: a first PWM controller that outputs gate signals for causing the power converter to act in a full bridge mode; a second PWM controller that outputs gate signals for causing the power converter to act in a half bridge mode; and a gate signal selector that automatically selects and outputs either the output of the first PWM controller or the output of the second PWM controller as gate signals of the switch elements, and that outputs, when the output of the second PWM controller is selected, the selected gate signals to the first half bridge and the second half bridge alternately every half cycle of the output voltage.