Please download the dossier by clicking on the dossier button x
×

Electrically Driven Power Steering System

  • US 20140088831A1
  • Filed: 08/08/2013
  • Published: 03/27/2014
  • Est. Priority Date: 09/24/2012
  • Status: Active Grant
First Claim
Patent Images

1. An electrically driven power steering system, comprising:

  • a steering mechanism that steers steerable wheels along with a steering operation of a steering wheel;

    a motor providing a steering force for the steering mechanism;

    a control unit drivingly controlling the motor;

    a command signal calculating section disposed in the control unit to calculate a vector control command signal for drivingly controlling the motor in accordance with a driving situation of a vehicle;

    a two-phase to three-phase converting section disposed in the control unit to convert the vector control command signal into a voltage command signal for each phase of the motor;

    a PWM control section disposed in the control unit to output a PWM duty signal (Du, Dv, Dw) of each phase of the motor in accordance with the voltage command signal of a corresponding one of the phases of the motor;

    an inverter, disposed in the control unit, constituted by a switching circuit controlled by means of the PWM duty signals (Du, Dv, Dw), and drivingly controlling the motor;

    a current sensor disposed in a direct current bus bar of the inverter to detect a direct current bus bar current;

    a phase current detecting section disposed in the control unit to detect or estimate a current value Iu, Iv, Iw of each phase of the motor on the direct current bus bar current and the PWM duty signals (Du, Dv, Dw);

    an estimated primary current calculating section disposed in the control unit to calculate an estimated primary current as follows;

    (Iu×

    Du+Iv×

    Dv+Iw×

    Dw)/100% on a basis of the current value (Iu, Iv, Iw) of each phase of the motor and the PWM duty signals (Du, Dv, Dw); and

    an abnormality monitoring section configured to detect an abnormality of the control unit on a basis of the direct current bus bar and the estimated primary current.

View all claims
  • 3 Assignments
Timeline View
Assignment View
    ×
    ×