Motor drive device provided with charging control unit

A motor drive device comprising:

• a converter configured to convert AC power supplied from an AC power source into DC power and output the DC power to a DC link;
• a capacitor disposed at the DC link;
• an inverter configured to convert the DC power in the DC link into AC power for driving a motor and output the AC power;
• a charging circuit including a charging resistor configured to prevent an inrush current during a time period of pre-charging of the capacitor;
• a charging control unit configured to control the pre-charging of the capacitor by the charging circuit;
• a power consumption status acquisition unit configured to acquire a parameter related to a power consumption status of an electric machine system supplied with AC power from the AC power source;
• and
• an abnormality determination unit configured to determine whether or not an abnormality has occurred based on the parameter during the time period of the pre-charging of the capacitor,
• wherein the abnormality determination unit is configured to determine that an abnormality has occurred when the parameter is lower than a fifth threshold value and determine that no abnormality has occurred when the parameter is equal to or more than the fifth threshold value.

A motor drive device comprising:

• a converter configured to convert AC power supplied from an AC power source into DC power and output the DC power to a DC link;
• a capacitor disposed at the DC link;
• an inverter configured to convert the DC power in the DC link into AC power for driving a motor and output the AC power;
• a charging circuit including a charging resistor configured to prevent an inrush current during a time period of pre-charging of the capacitor;
• a charging control unit configured to control the pre-charging of the capacitor by the charging circuit;
• and
• an abnormality determination unit configured to determine whether or not an abnormality has occurred based on at least one of a measurement value of a voltage of the capacitor or a measurement value of a current flowing through the DC link during the time period of the pre-charging of the capacitor, wherein
• the charging circuit includes:
• the charging resistor,
• a charging switch connected in series to the charging resistor and configured to open and close an electric path under control of the charging control unit, and
• a main circuit switch connected in parallel to a set of the charging resistor and the charging switch connected in series, and configured to open and close an electric path between the converter and the capacitor or an electric path between the converter and the AC power source under control of the charging control unit,
• wherein the pre-charging of the capacitor is configured to be executed when the charging switch is controlled to be in a closed state and the main circuit switch is controlled to be in an open state by the charging control unit, and
• wherein, when the capacitor is charged to a predetermined charging voltage after the pre-charging of the capacitor is started, the charging switch is configured to be controlled to be in an open state and the main circuit switch is configured to be controlled to be in a closed state by the charging control unit, whereby the pre-charging of the capacitor is completed.