Drive controller, drive unit, and power steering
A drive controller according to an aspect controls drive of a three-phase motor, and includes an electric value calculation unit that calculates an electric value in each of coordinate axes of rotating coordinates of the three-phase motor based on an electric value that is at least one of a current value and a voltage value generated in the three-phase motor, and a fault determination unit that determines a fault phase having a fault in phases of the three-phase motor by combining positive-negative information on at least one of a difference between a calculation electric value calculated by the electric value calculation unit and a target electric value indicating a control target of an electric value in each of the coordinate axes, and a variation of the difference, with each of the coordinate axes.
1. A drive controller for controlling drive of a three-phase motor, the drive controller comprising:
an electric value calculation unit configured to calculate an electric value in each of coordinate axes of rotating coordinates of the three-phase motor based on an electric value that is at least one of a current value or a voltage value generated in the three-phase motor;
a sign information storage unit storing sign information; and
a fault determination unit configured to
combine, for each of the coordinate axes, positive-negative information on at least one of
(i) a difference between the electric value calculated by the electric value calculation unit and a target electric value indicating a control target of an electric value in said each of the coordinate axes, or
(ii) a variation of the difference, and determine, among phases of the three-phase motor, a phase with the sign information coinciding with the combined positive-negative information as a fault phase having a fault, wherein
the drive controller is configured to, in response to determining the fault phase, switch control of the three-phase motor to a control of the three-phase motor under abnormal conditions.
2. The drive controller according to claim 1 , wherein
the electric value is a current value.
3. The drive controller according to claim 1 , wherein
the fault determination unit uses the combined positive-negative information on the variation of the difference.
4. The drive controller according to claim 1 , wherein
the three-phase motor is an unconnected motor.
5. The drive controller according to claim 1 , wherein
the fault determination unit is configured to determine the fault phase by checking consistency between (a) the sign information including a positive or a negative of a contribution component that is included in the electric value of each phase of the three-phase motor and contributes to the electric value in each of the coordinate axes, and (b) the combined positive-negative information.
6. The drive controller according to claim 5 , wherein
the fault determination unit is configured to use expressions below that are each expressed as the positive or the negative of the contribution component,
q _affect( a )=sgn(−sin θ)
q _affect( b )=sgn(−sin θ−2π/3)
q _affect( c )=sgn(−sin θ−4π/3)
d _affect( a )=sgn(cos θ)
d _affect( b )=sgn(cos θ−2π/3)
d _affect( c )=sgn(cos θ−4π/3)
where each of the q_affect (a), the q_affect (b), and the q_affect (c) indicates a positive or a negative of a contribution component of a q-axis electric value in corresponding one of an a-phase, a b-phase, or a c-phase,
each of the d_affect (a), the d_affect (b), and the d_affect (c) indicates a positive or a negative of a contribution component of a d-axis electric value in corresponding one of the a-phase, the b-phase, or the c-phase,
θ is an electrical angle of the three-phase motor, and
sgn (x) is expressed as −1 when x is less than 0, as 0 when x is 0, and 1 when x is more than 0.
7. The drive controller according to claim 1 , wherein
the drive controller is configured to, in response to determining the fault phase,
determine a fault location, and
switch the control of the three-phase motor to the control of the three-phase motor under the abnormal conditions corresponding to the fault location.
8. A drive unit comprising:
a drive controller; and
a three-phase motor that is driven under control of the drive controller, wherein
the drive controller comprises:
an electric value calculation unit configured to calculate an electric value in each of coordinate axes of rotating coordinates of the three-phase motor based on an electric value that is at least one of a current value or a voltage value generated in the three-phase motor;
a sign information storage unit storing sign information; and
a fault determination unit configured to
combine, for each of the coordinate axes, positive-negative information on at least one of
(i) a difference between the electric value calculated by the electric value calculation unit and a target electric value indicating a control target of an electric value in said each of the coordinate axes, or
(ii) a variation of the difference, and
determine, among phases of the three-phase motor, a phase with the sign information coinciding with the combined positive-negative information as a fault phase having a fault, and
the drive controller is configured to, in response to determining the fault phase, switch control of the three-phase motor to a control of the three-phase motor under abnormal conditions.
9. The drive unit according to claim 8 , wherein
the drive controller is configured to, in response to determining the fault phase,
determine a fault location, and
switch the control of the three-phase motor to the control of the three-phase motor under the abnormal conditions corresponding to the fault location.
10. A power steering comprising:
a drive controller;
a three-phase motor that is driven under control of the drive controller; and
a power steering mechanism that is driven by the three-phase motor, wherein
the drive controller comprises:
an electric value calculation unit configured to calculate an electric value in each of coordinate axes of rotating coordinates of the three-phase motor based on an electric value that is at least one of a current value or a voltage value generated in the three-phase motor;
a sign information storage unit storing sign information; and
a fault determination unit configured to
combine, for each of the coordinate axes, positive-negative information on at least one of
(i) a difference between the electric value calculated by the electric value calculation unit and a target electric value indicating a control target of an electric value in said each of the coordinate axes, or
(ii) a variation of the difference, and
determine, among phases of the three-phase motor, a phase with the sign information coinciding with the combined positive-negative information as a fault phase having a fault, and
the drive controller is configured to, in response to determining the fault phase, switch control of the three-phase motor to a control of the three-phase motor under abnormal conditions.
11. The power steering according to claim 10 , wherein
the drive controller is configured to, in response to determining the fault phase,
determine a fault location, and
switch the control of the three-phase motor to the control of the three-phase motor under the abnormal conditions corresponding to the fault location.