Patent ID: 9543882
Date: 2017-01-10
CPC Classifications: H02J,H02M,H02P

Claim:
1. An AC motor drive system comprising: a converter that supplies DC power; an inverter that converts the DC power into AC power; a DC bus that connects the converter and the inverter; an AC motor driven by the AC power; a DC-voltage-value detecting unit that detects a DC bus voltage value on an output side of the converter; a power storage device that is charged with the DC power from the DC bus and discharges the charged DC power to the DC bus; a charging/discharging circuit connected to the DC bus in parallel with the inverter and connected between the DC bus and the power storage device, the charging/discharging circuit causing the power storage device to be charged and discharge; a charging/discharging-current-value detecting unit that detects a charging/discharging current value of the power storage device; and a charging/discharging control unit that outputs a control signal for controlling the inverter on a basis of the DC bus voltage value and the charging/discharging current value, wherein when regenerative power from the AC motor via the inverter exceeds a predetermined power threshold, the charging/discharging control unit causes the power storage device to be charged such that the DC bus voltage value becomes a voltage threshold corresponding to the power threshold and causes a charging current at a start time of charging to the power storage device to start from a charging current value that is based on a DC bus voltage value of the DC bus.