Motor-driven power steering apparatus
First Claim
1. A motor-driven power steering apparatus for a vehicle, comprising:
- a steering mechanism for steering the vehicle in accordance with operation of a steering wheel;
a motor mechanically coupled to the steering mechanism and generating assisting force to be imparted to the steering mechanism;
control signal generation means for generating a motor control signal on the basis of at least steering torque applied to the steering wheel;
motor drive means for driving the motor in accordance with the motor control signal;
a step-up circuit provided in a current supply circuit extending from a battery to the motor drive means, the step-up circuit including a step-up coil whose one end is connected to the battery for reception of battery voltage, a first switching element connected between the other end of the step-up coil and the ground, a second switching element connected between the other end of the step-up coil and an output terminal, and a capacitor connected between the output terminal and the ground and smoothing output voltage which is produced by means of the step-up coil and appears at the output terminal; and
step-up circuit control means for detecting the output voltage and controlling the first and second switching elements on the basis of difference between a target output voltage and the detected output voltage in such a manner that during power generation periods, at least the first switching element is turned on and off in order to increase the output voltage supplied to the motor through step-up operation, and during regeneration periods, at least the second switching element is turned on and off.
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Accused Products
Abstract
A motor-driven power steering apparatus includes a motor for generating assisting force to be imparted to a steering mechanism, a control signal generation section for generating a motor control signal on the basis of at least steering torque applied to a steering wheel, a motor drive unit for driving the motor in accordance with the motor control signal, and a step-up circuit provided between a battery to the motor drive unit. The step-up circuit includes a step-up coil whose one end is connected to the battery, a first switching element connected between the other end of the step-up coil and the ground, a second switching element connected between the other end of the step-up coil and an output terminal, and a capacitor connected between the output terminal and the ground and smoothing output voltage appearing at the output terminal. The apparatus further includes a step-up circuit control unit which detects the output voltage and controls the first and second switching elements on the basis of difference between a target output voltage and the detected output voltage. During power generation periods, at least the first switching element is turned on and off in order to increase the output voltage supplied to the motor through step-up operation. During regeneration periods, at least the second switching element is turned on and off.
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Citations
27 Claims
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1. A motor-driven power steering apparatus for a vehicle, comprising:
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a steering mechanism for steering the vehicle in accordance with operation of a steering wheel;
a motor mechanically coupled to the steering mechanism and generating assisting force to be imparted to the steering mechanism;
control signal generation means for generating a motor control signal on the basis of at least steering torque applied to the steering wheel;
motor drive means for driving the motor in accordance with the motor control signal;
a step-up circuit provided in a current supply circuit extending from a battery to the motor drive means, the step-up circuit including a step-up coil whose one end is connected to the battery for reception of battery voltage, a first switching element connected between the other end of the step-up coil and the ground, a second switching element connected between the other end of the step-up coil and an output terminal, and a capacitor connected between the output terminal and the ground and smoothing output voltage which is produced by means of the step-up coil and appears at the output terminal; and
step-up circuit control means for detecting the output voltage and controlling the first and second switching elements on the basis of difference between a target output voltage and the detected output voltage in such a manner that during power generation periods, at least the first switching element is turned on and off in order to increase the output voltage supplied to the motor through step-up operation, and during regeneration periods, at least the second switching element is turned on and off. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification