Electric Power Steering Apparatus and Method for Controlling the Electric Power Steering Apparatus
First Claim
1. :
- An electric power steering apparatus, comprising;
a steering mechanism that steers steering wheels in response to a steering operation of a driver'"'"'s steering wheel;
an electric motor that is fitted to the steering mechanism and that rotates using electric power supplied from an electric power supply device to generate a force used to assist the steering operation; and
a motor control unit that controls an operation of the electric motor based on a manner in which the steering operation of the driver'"'"'s steering wheel is performed,whereinthe electric power supply device includes at least two electric power supply units connected in parallel, which are a main electric power supply unit and a sub-electric power supply unit that outputs a voltage lower than a voltage output from the main electric power supply unit, the electric power supply device being structured such that electric power is supplied to the electric motor from one of the main electric power supply unit and the sub-electric power supply unit, andthe motor control unit includes;
a vector control unit that controls rotation of the electric motor by executing vector control indicated by a two-phase rotating flux coordinate system where a direction in which the electric motor rotates is used as a q-axis and a direction perpendicular to the direction in which the electric motor rotates is used as a d-axis; and
a motor speed compensation unit that increases, when electric power is supplied to the electric motor from the sub-electric power supply unit, a d-axis current used as a field-weakening control current by a larger amount than when electric power is supplied to the electric motor from the main electric power supply unit so that a decrease in a motor speed due to a decrease in a voltage output from the electric power supply device is suppressed.
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Accused Products
Abstract
An electric power steering apparatus includes an electric power supply device that includes a main electric power unit that supplies high-tension electric power and a sub-electric power supply unit that supplies low-tension electric power, the main electric power unit and the sub-electric power supply unit being connected to each other in parallel, and that supplies electric power to the electric motor from one of the main electric power supply unit and the sub-electric power supply unit. An assist ECU calculates a correction coefficient based on which a d-axis target current increases with a decrease in voltage output from the electric power supply device, and calculates a final corrected d-axis target current by multiplying the d-axis target current by the correction coefficient.
23 Citations
7 Claims
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1. :
- An electric power steering apparatus, comprising;
a steering mechanism that steers steering wheels in response to a steering operation of a driver'"'"'s steering wheel; an electric motor that is fitted to the steering mechanism and that rotates using electric power supplied from an electric power supply device to generate a force used to assist the steering operation; and a motor control unit that controls an operation of the electric motor based on a manner in which the steering operation of the driver'"'"'s steering wheel is performed, wherein the electric power supply device includes at least two electric power supply units connected in parallel, which are a main electric power supply unit and a sub-electric power supply unit that outputs a voltage lower than a voltage output from the main electric power supply unit, the electric power supply device being structured such that electric power is supplied to the electric motor from one of the main electric power supply unit and the sub-electric power supply unit, and the motor control unit includes; a vector control unit that controls rotation of the electric motor by executing vector control indicated by a two-phase rotating flux coordinate system where a direction in which the electric motor rotates is used as a q-axis and a direction perpendicular to the direction in which the electric motor rotates is used as a d-axis; and a motor speed compensation unit that increases, when electric power is supplied to the electric motor from the sub-electric power supply unit, a d-axis current used as a field-weakening control current by a larger amount than when electric power is supplied to the electric motor from the main electric power supply unit so that a decrease in a motor speed due to a decrease in a voltage output from the electric power supply device is suppressed. - View Dependent Claims (2, 3, 4, 5, 6)
- An electric power steering apparatus, comprising;
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7. :
- A method for controlling an electric power steering apparatus including a steering mechanism that steers steering wheels in response to a steering operation of a driver'"'"'s steering wheel;
an electric motor that is fitted to the steering mechanism and that rotates using electric power supplied from an electric power supply device to generate a force used to assist the steering operation; and
a motor control unit that controls an operation of the electric motor based on a manner in which the steering operation of the driver'"'"'s steering wheel is performed, comprisingsupplying electric power to the electric motor from one of at least two electric power supply units which are included in the electric power supply device, which are connected in parallel, and which include a main electric power supply unit and a sub-electric power supply unit that outputs a voltage lower than a voltage output from the main electric power supply unit; controlling, using the motor control unit, rotation of the electric motor by executing vector control indicated by a two-phase rotating flux coordinate system where a direction in which the electric motor rotates is used as a q-axis and a direction perpendicular to the direction in which the electric motor rotates is used as a d-axis; and increasing, using the motor control unit, when electric power is supplied to the electric motor from the sub-electric power supply unit, a d-axis current used as a field-weakening control current by a larger amount than when electric power is supplied to the electric motor from the main electric power supply unit so that a decrease in a motor speed due to a decrease in a voltage output from the electric power supply device is suppressed.
- A method for controlling an electric power steering apparatus including a steering mechanism that steers steering wheels in response to a steering operation of a driver'"'"'s steering wheel;
Specification