Voltage Imbalance Assessment Method and Power Conversion Device

A power conversion device comprising:

• a forward converter that rectifies a voltage from a three-phase AC power supply;
• a smoothing capacitor that smooths the rectified voltage;
• a voltage detection unit that detects a voltage of the smoothing capacitor;
• and
• an arithmetic operation unit that is connected to the voltage detection unit,
• wherein the arithmetic operation unit
• acquires time-series data of the voltage detected by the voltage detection unit,
• generates data indicating frequency components based on the acquired time-series data,
• compares a magnitude of a component being four times a power supply frequency with a magnitude of a component being six times the power supply frequency in the data indicating the frequency components, and
• assesses voltage imbalance of the three-phase AC power supply based on the comparison.