Electric power steering apparatus
First Claim
1. An electric power steering apparatus for generating a steering assist force by a motor, comprising:
- a battery for supplying an electric power to the motor;
an auxiliary power supply connected in series with the battery and capable of supplying an electric power to the motor;
a detector for detecting a failure of the battery;
a charge-discharge circuit including a charge circuit for charging the auxiliary power supply by turning on and off a voltage-boosting switching device interposed in an inductance circuit powered by the battery and selectively configuring a first output mode or a second output mode, the first output mode defining a state that the electric power is supplied to the motor by way of a first electrical conduction path through which a voltage of the battery is applied to an electrical conduction path to ground, the second output mode defining a state that the electric power is supplied to the motor by way of a second electrical conduction path through which a voltage of a source including the series-connected battery and auxiliary power supply is applied to the electrical conduction path to ground; and
a control circuit for driving the charge-discharge circuit to select either of the first output mode and the second output mode in response to a required steering assist force, the control circuit connecting the first electrical conduction path to the electrical conduction path to ground by continuously holding the switching device in an on-state at the time of detection of a failure of the battery by the detector, the control circuit also driving the charge-discharge circuit to select the second output mode to thereby supply the motor with the electric power only from the auxiliary power supply.
1 Assignment
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Accused Products
Abstract
An electric power steering apparatus includes a charge-discharge circuit including a circuit charging an auxiliary power supply by turning on and off an MOS-FET for voltage boosting and that selectively configures a first output mode in which an electric power is supplied to a motor by a first electrical conduction path to which a voltage of a battery is applied or a second output mode in which the electric power is supplied to the motor by a second electrical conduction path to which a voltage of a source of the series-connected battery and auxiliary power supply is applied. When a failure of the battery is detected, the electric power steering apparatus connects the first conduction path to an electrical conduction path to ground by continuously holding the MOS-FET in an on-state and drives the charge-discharge circuit to select the second output mode, thereby configuring a circuit to supply the motor with the electric power only from the auxiliary power supply.
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Citations
4 Claims
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1. An electric power steering apparatus for generating a steering assist force by a motor, comprising:
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a battery for supplying an electric power to the motor; an auxiliary power supply connected in series with the battery and capable of supplying an electric power to the motor; a detector for detecting a failure of the battery; a charge-discharge circuit including a charge circuit for charging the auxiliary power supply by turning on and off a voltage-boosting switching device interposed in an inductance circuit powered by the battery and selectively configuring a first output mode or a second output mode, the first output mode defining a state that the electric power is supplied to the motor by way of a first electrical conduction path through which a voltage of the battery is applied to an electrical conduction path to ground, the second output mode defining a state that the electric power is supplied to the motor by way of a second electrical conduction path through which a voltage of a source including the series-connected battery and auxiliary power supply is applied to the electrical conduction path to ground; and a control circuit for driving the charge-discharge circuit to select either of the first output mode and the second output mode in response to a required steering assist force, the control circuit connecting the first electrical conduction path to the electrical conduction path to ground by continuously holding the switching device in an on-state at the time of detection of a failure of the battery by the detector, the control circuit also driving the charge-discharge circuit to select the second output mode to thereby supply the motor with the electric power only from the auxiliary power supply. - View Dependent Claims (2, 3, 4)
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Specification