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Method and apparatus for operating an electric vehicle drive system during periods of sensor malfunction

  • US 5,661,380 A
  • Filed: 11/07/1995
  • Issued: 08/26/1997
  • Est. Priority Date: 11/07/1994
  • Status: Expired due to Fees
First Claim
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1. A protection apparatus for an electric vehicle of the type comprising an inverter for converting a direct current electric power source of a battery to a variable voltage and variable frequency alternating current power source, a three-phase alternating current motor for driving the vehicle, a current sensor for detecting current flowing to said three-phase alternating current motor, a torque command calculator for determining a torque command of said three-phase alternating current motor based on a degree of opening of an accelerator detected by an accelerator sensor, an alternating current command generator for generating a current command to control current flowing to said three-phase alternating current motor based on said torque command and an output of said current sensor, a current control circuit for generating a voltage signal based on said current command and the current flowing to said three-phase alternating current motor, a limiter for limiting the voltage signal generated by said current control circuit and PWM signal generating means for generating a PWM signal to control said inverter based on an output from the limiter;

  • said protection apparatus comprising;

    a detector for detecting abnormal operation of said current sensor; and

    a back-up circuit responsive to detection of said abnormal operation for causing an output of said limiter to be set to zero, and for generating a voltage command based on a back-up control voltage output from said alternating current command generating means, said PWM signal generating means generating a PWM signal for control of said inverter using said voltage command.

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