Current/voltage control apparatus for elevator system

A current/voltage control apparatus for an elevator system including an inverter for inverting a direct-current voltage into an alternating-current voltage of a variable voltage-and-frequency-type to be applied to an induction motor, an inverter controller for detecting a current phase flowing in the induction motor, generating a voltage instruction based on the detected phase and controlling the inverter, and an inverter driving unit for receiving an output signal from the inverter controller, generating a pulse width modulation signal corresponding thereto and driving the inverter, said control apparatus comprising:

• a voltage limiter for setting a limit voltage value which is proportional to an operational frequency of the induction motor and applying the voltage below the limit voltage value to the inverter driving unit;
• a zero phase component current detector for detecting a zero phase component current and outputting an inverter driving stop signal to the inverter driving unit when the thusly detected current exceeds a predetermined reference value;
• and
• a current deviation detector for detecting a current deviation value and outputting an inverter driving stop signal to the inverter driving unit when the current deviation value exceeds a predetermined reference value continuously for a predetermined time.