POWER CONVERSION DEVICE

摘要

For the purpose of obtaining a power conversion apparatus of a three-level inverter system that can reduce a withstand voltage of an isolation transformer for a semiconductor driving circuit and secure long-term reliability under a situation in which a conversion target power supply voltage reaches a high voltage, both of reference potentials of semiconductor driving circuits and reference potentials between primary sides of isolation transformers for supplying isolated direct-current power to the semiconductor driving circuits corresponding to the isolation transformers and a secondary side of an inverter transformer are supplied from the respective same connection ends among connection ends of four main circuit capacitors. Therefore, a potential difference of reference potential between primary sides and secondary sides of a plurality of isolation transformers is 0 volt even if a conversion target power supply voltage reaches a high voltage such as DC 1000 volts. Accordingly, even under a situation in which a conversion target power supply voltage reaches a high voltage such as DC 1000 volts, corona discharge does not occur between the primary side and the secondary side of the isolation transformer. Therefore, insulation deterioration does not occur and long-term reliability of the isolation transformer is improved.