Controller of AC electric vehicle

A controller of an AC electric vehicle comprising:

• a transformer that receives an AC voltage from an AC overhead contact line;
• a converter that converts an AC voltage output from the transformer to a DC voltage;
• an inverter that converts the DC voltage from the converter to an AC voltage and outputs the AC voltage to an AC electric motor;
• a current detector that detects an output current from the transformer;
• and
• a control unit including a converter control unit that controls an output of the converter according to a gate enable signal based on a detection current detected by the current detector and a power failure detector that detects a power failure generated in the AC overhead contact line based on the detection current,
• wherein the power failure detector includes:
• corresponding to a predetermined first specific frequency set value from the detection current and outputs the extracted current component as a first specific-frequency current;
• a subtractor that subtracts the first specific-frequency current from the detection current and outputs a subtraction result as a current deviation;
• a second specific-frequency-current computation unit that extracts a current component corresponding to a predetermined second specific frequency set value from the current deviation and outputs the extracted current component as a second specific-frequency current;
• and
• a power failure detector unit that compares the second specific-frequency current with a predetermined power-failure detection-current set value, and outputs a power-failure detection signal when the second specific-frequency current is larger than the power-failure detection-current set value, and
• wherein the converter control unit stops an operation of the converter by stopping the gate enable signal based on an input power-failure detection signal.