Motor controller and electric power steering apparatus

US 7,782,000 B2
Filed: 05/28/2008
Issued: 08/24/2010
Est. Priority Date: 06/01/2007
Status: Active Grant

First Claim

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1. A motor controller comprising:

signal output means that outputs a motor control signal; and

a driver circuit that supplies a three-phase drive power to a motor based on the motor control signal,wherein the signal output means includes calculating means that calculates a d-axis current command value and a q-axis current command value of a d/q coordinate system as electric current command values, signal generating means that generates the motor control signal by performing current feedback control of the d/q coordinate system based on the d-axis current command value and the q-axis current command value, and anomaly detecting means that is capable of detecting a failed electric current flow in any one of the phases of the motor,wherein, when a failed electric current flow is detected, the signal output means outputs the motor control signal using two phases other than the phase with the failed electric current flow as electric current flowing phases,wherein a maximum value of an electric current flowable in each of the phases of the motor is set for each of phase current values of the motor, andwherein, when a failed electric current flow occurs, the calculating means calculates the d-axis current command value changing along a tangent curve with a predetermined rotation angle corresponding to the phase with the failed electric current flow as an asymptotic line, and calculates the d-axis current command value and the q-axis current command value in such a manner that the phase current value of each of the electric current flowing phases becomes constant at the maximum value in a rotating angle range in which the phase current value needs to be restricted based on the maximum value.

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Abstract

When a failure of an electric current flow occurs in any one of phases, a microcomputer calculates a d-axis current command value that changes along a tangent curve with predetermined rotation angles as asymptotic lines. The microcomputer continuously outputs a motor control signal using two phases other than the phase with the failed electric current as electric current flowing phases by performing current feedback control in correspondence with the d-axis current command value. In such two-phase drive operation, the microcomputer calculates the d-axis current command value and a q-axis current command value in such a manner that the phase current values of the electric current flowing phases become constant at respective maximum values of flowable electric currents, which are set for the phases, in rotation angle restriction ranges in which the phase current values need to be restricted in correspondence with the maximum values, or electric current restriction ranges.

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3 Claims

1. A motor controller comprising:
- signal output means that outputs a motor control signal; and
  
  a driver circuit that supplies a three-phase drive power to a motor based on the motor control signal,wherein the signal output means includes calculating means that calculates a d-axis current command value and a q-axis current command value of a d/q coordinate system as electric current command values, signal generating means that generates the motor control signal by performing current feedback control of the d/q coordinate system based on the d-axis current command value and the q-axis current command value, and anomaly detecting means that is capable of detecting a failed electric current flow in any one of the phases of the motor,wherein, when a failed electric current flow is detected, the signal output means outputs the motor control signal using two phases other than the phase with the failed electric current flow as electric current flowing phases,wherein a maximum value of an electric current flowable in each of the phases of the motor is set for each of phase current values of the motor, andwherein, when a failed electric current flow occurs, the calculating means calculates the d-axis current command value changing along a tangent curve with a predetermined rotation angle corresponding to the phase with the failed electric current flow as an asymptotic line, and calculates the d-axis current command value and the q-axis current command value in such a manner that the phase current value of each of the electric current flowing phases becomes constant at the maximum value in a rotating angle range in which the phase current value needs to be restricted based on the maximum value.
- View Dependent Claims (2, 3)
- - 2. The motor controller according to claim 1, wherein, when a failed electric current flow occurs, the calculating means calculates the d-axis current command value in correspondence with the phase with the failed electric current flow using the following expressions:
    - When the electric current flow fails in the U phase;
      
      $I_{d}^{*} = I_{q}^{*} \frac{\sin θ}{\cos θ} = I_{q}^{*} \tan θ$ When the electric current flow fails in the V phase;
      
      $I_{d}^{*} = - I_{q}^{*} \frac{\sin (θ + \frac{π}{3})}{\sin (θ - \frac{π}{6})} = I_{q}^{*} \tan (θ - \frac{2 π}{3})$ When the electric current flow fails in the W Phase;
      
      $I_{d}^{*} = - I_{q}^{*} \frac{\sin (θ + \frac{2 π}{3})}{\sin (θ + \frac{π}{6})} = I_{q}^{*} \tan (θ + \frac{2 π}{3})$ (θ
      
      ;
      
      rotation angle, Id*;
      
      d-axis current command value, Iq*;
      
      q-axis current command value), andwherein the calculating means calculates the d-axis current command value and the q-axis current command value in the rotation angle range in which the phase currents need be restricted, using the following expressions;
      
      When the electric current flow fails in the U Phase;
      
      $if θ 1 < θ < π / 2 or 3 π / 2 < θ < θ 4$ $\begin{matrix} I_{d}^{*} = \sqrt{2} I_{x_max} \sin θ & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = - \sqrt{2} I_{x_max} \sin θ & (I_{q}^{*} < 0) \\ I_{q}^{*} = \sqrt{2} I_{x_max} \cos θ & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = - \sqrt{2} I_{x_max} \cos θ & (I_{q}^{*} < 0) \end{matrix}$ $if π / 2 < θ < θ 2 or θ 3 < θ < 3 π / 2$ $\begin{matrix} I_{d}^{*} = - \sqrt{2} I_{x_max} \sin θ & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = \sqrt{2} I_{x_max} \sin θ & (I_{q}^{*} < 0) \\ I_{q}^{*} = - \sqrt{2} I_{x_max} \cos θ & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = \sqrt{2} I_{x_max} \cos θ & (I_{q}^{*} < 0) \end{matrix}$ $provided that;$ $\begin{matrix} θ_{1} = \cos^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) & (I_{q}^{*} ≧ 0) \\ \cos^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) & (I_{q}^{*} < 0) \\ θ_{2} = \cos^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) & (I_{q}^{*} ≧ 0) \\ \cos^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) & (I_{q}^{*} < 0) \\ θ_{3} = 2 π - θ_{2} \\ θ_{4} = 2 π - θ_{1} \end{matrix}$ When the electric current flow fails in the V Phase;
      
      $if θ 1 < θ < π / 6 or 7 π / 6 < θ < θ 4$ $\begin{matrix} I_{d}^{*} = I_{x_max} (\sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = - I_{x_max} (\sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} < 0) \\ I_{q}^{*} = I_{x_max} (- \sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = - I_{x_max} (- \sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} < 0) \end{matrix}$ $if π / 6 < θ < θ 2 or θ 3 < θ < 7 π / 6$ $\begin{matrix} I_{d}^{*} = - I_{x_max} (\sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = I_{x_max} (\sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} < 0) \\ I_{q}^{*} = - I_{x_max} (- \sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = I_{x_max} (- \sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} < 0) \end{matrix}$ $provided that;$ $\begin{matrix} θ_{1} = \sin^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) + \frac{π}{6} & (I_{q}^{*} ≧ 0) \\ \sin^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) + \frac{π}{6} & (I_{q}^{*} < 0) \\ θ_{2} = \sin^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) + \frac{π}{6} & (I_{q}^{*} ≧ 0) \\ \sin^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) + \frac{π}{6} & (I_{q}^{*} < 0) \\ θ_{3} = \frac{4 π}{3} - θ_{2} \\ θ_{4} = \frac{4 π}{3} - θ_{1} \end{matrix}$ When the electric current flow fails in the W phase;
      
      $if θ 1 < θ < 5 π / 6 or 11 π / 6 < θ < θ 4$ $\begin{matrix} I_{d}^{*} = I_{x_max} (- \sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = - I_{x_max} (- \sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} < 0) \\ I_{q}^{*} = I_{x_max} (\sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = - I_{x_max} (\sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} < 0) \end{matrix}$ $if 5 π / 6 < θ < θ 2 or θ 3 < θ < 11 π / 6$ $\begin{matrix} I_{d}^{*} = - I_{x_max} (- \sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} ≧ 0) \\ I_{d}^{*} = I_{x_max} (- \sqrt{\frac{3}{2}} \cos θ + \sqrt{\frac{1}{2}} \sin θ) & (I_{q}^{*} < 0) \\ I_{q}^{*} = - I_{x_max} (\sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} ≧ 0) \\ I_{q}^{*} = I_{x_max} (\sqrt{\frac{3}{2}} \sin θ + \sqrt{\frac{1}{2}} \cos θ) & (I_{q}^{*} < 0) \end{matrix}$ $provided that;$ $\begin{matrix} θ_{4} = \sin^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) - \frac{π}{6} & (I_{q}^{*} ≧ 0) \\ \sin^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) - \frac{π}{6} & (I_{q}^{*} < 0) \\ θ_{3} = \sin^{- 1} (\frac{- I_{q}^{*}}{\sqrt{2} I_{x_max}}) - \frac{π}{6} & (I_{q}^{*} ≧ 0) \\ \sin^{- 1} (\frac{I_{q}^{*}}{\sqrt{2} I_{x_max}}) - \frac{π}{6} & (I_{q}^{*} < 0) \\ θ_{2} = \frac{2 π}{3} - θ_{3} \\ θ_{1} = \frac{2 π}{3} - θ_{4} \end{matrix}$ (Id*;
      
      d-axis current command value, Iq*;
      
      q-axis current command value, Ix_max;
      
      maximum value of flowable electric current).
  - 3. An electric power steering apparatus having the motor controller according to claim 1.

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Current Assignee
Jtekt Corporation (Toyota Motor Corporation)
Original Assignee
Jtekt Corporation (Toyota Motor Corporation)
Inventors
Suzuki, Hiroshi
Primary Examiner(s)
Benson; Walter
Assistant Examiner(s)
Colon-Santana; Eduardo

Application Number

US12/128,304
Publication Number

US 20080297958A1
Time in Patent Office

818 Days
Field of Search

318/700, 318/400.01, 318/400.02, 318/430, 318/432, 318/434, 701/41, 180/443
US Class Current

318/434
CPC Class Codes

B62D 5/0484   for reaction to failures, e...

B62D 5/0487   detecting motor faults B62D...

H02P 21/22   Current control, e.g. using...

H02P 29/032   Preventing damage to the mo...

Motor controller and electric power steering apparatus

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Motor controller and electric power steering apparatus

First Claim

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Abstract

53 Citations

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Specification

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