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US 8,418,801 B2Granted
Electric power steering system
AssigneeJtekt Corporation
InventorKeisuke Izutani
Life of this patent
Estimating the term…
Abstract
An inverter energy consumption calculating portion estimates the actual power consumption of a steering operation assist motor after an engine is placed in an idle-stop state, and a command value of current to be supplied to the steering operation assist motor is limited such that the command value is smaller as the energy consumption is larger. The inverter energy consumption calculating portion calculates the energy consumption of an inverter drive circuit by integrating an amount of electric power consumed by the drive circuit.
Claims12
An electric power steering system, comprising:
- a unit that detects an idle-stop state of an engine;
- a steering operation assist motor that produces steering operation assist force;
- a drive circuit that drives the steering operation assist motor;
- a power source that powers the drive circuit;
- an energy consumption calculating unit that calculates or estimates an amount of energy that is consumed by the drive circuit from when the engine is placed in the idle-stop state;
- a current limiting unit that limits a command value of current to be supplied to the steering operation assist motor such that the current command value is smaller as the amount of energy consumed by the drive circuit is larger, the amount of energy consumed by the drive circuit being calculated or estimated by the energy consumption calculating unit;
- and
- a motor drive controlling unit that controls the drive circuit based on the current command value limited by the current limiting unit.
5 more elements
Dependencies are inferred from the claim text.