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1. (WO2015045565) POWER CONVERSION DEVICE AND CONTROL METHOD

Pub. No.:    WO/2015/045565    International Application No.:    PCT/JP2014/068532
Publication Date: Fri Apr 03 01:59:59 CEST 2015 International Filing Date: Sat Jul 12 01:59:59 CEST 2014
IPC: H02M 7/48
Applicants: HITACHI INDUSTRIAL EQUIPMENT SYSTEMS CO., LTD.
株式会社日立産機システム
Inventors: ARAO Yusuke
荒尾 祐介
TANABE Keisuke
田邉 啓輔
Title: POWER CONVERSION DEVICE AND CONTROL METHOD
Abstract:
This invention provides a method in which, if the current flowing through a power conversion device or the DC voltage across said power conversion device increases, a carrier frequency is lowered and an overcurrent level or an overvoltage level is raised, thereby expanding the range of use of said power conversion device while preventing breakdown of switching elements. This invention also provides a product that can make maximum use of inexpensive switching elements, reducing cost. This power conversion device is provided with the following: a DC smoothing unit that smoothes a DC voltage; a power conversion unit that converts said DC voltage to a desired AC voltage; a current detector that detects the current outputted by the power conversion unit; a voltage detector that detects the voltage across the DC smoothing unit; and a control circuit that controls the on/off states of switching elements in the power conversion unit. The control circuit controls a carrier frequency on the basis of the current detected by the current detector and sets an overcurrent level on the basis of said carrier frequency and the voltage detected by the voltage detector.