Rotation Detection Device Voltage Stabilization
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Solution Overview
Problem
Existing rotation detection systems in electric power steering devices face challenges in maintaining accurate rotation detection when the vehicle's power supply voltage drops, leading to potential inhibition of normal operation and increased power consumption.
Innovation Solution
A rotation detection device incorporating a step-up power supply circuit and a step-down power supply circuit, along with a dual power supply path system, which switches between paths based on voltage levels to maintain stable voltage for the rotation detection circuit, ensuring continuous operation even when the vehicle's power supply voltage is lowered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotation detection circuit is continuously operated to detect motor rotation number, then the reliability of rotation detection is improved, but the power consumption of the battery is increased
Solution Approach 1:
The rotation angle sensor operates intermittently at predetermined cycles instead of continuously, reducing power consumption while still detecting motor rotation number. The control device determines rotation number based on detection results from these periodic measurements, even when the power switch is turned off.
2Use of energy by moving object
If the rotation angle sensor operates intermittently to reduce power consumption, then the battery power consumption is reduced, but the measurement precision of rotation detection is degraded
Solution Approach 1:
The control device stores the last detected rotation angle and uses it to calculate motor rotation number during periods when the sensor is not actively measuring. This preliminary detection approach maintains measurement capability without requiring continuous sensor operation, thus preserving precision while reducing power consumption.
3Device complexity
If the control device operates without voltage boosting when battery voltage is low, then the device complexity is reduced, but the reliability of operation is degraded
Solution Approach 1:
A booster circuit is introduced as an intermediary component between the battery and the control device. When battery voltage is insufficient, the booster boosts the voltage to ensure the control device can operate reliably. This intermediary solution maintains operation reliability without requiring fundamental redesign of the power supply system.
4Use of energy by moving object
If the power supply voltage is allowed to drop, then the power consumption is reduced, but the stability of the rotation detection circuit is degraded
Solution Approach 1:
The power supply system dynamically adjusts voltage levels based on operational needs. The booster circuit activates only when battery voltage is insufficient, providing voltage boosting temporarily. When voltage is sufficient, the booster remains inactive, allowing the system to operate with lower power consumption while maintaining voltage stability when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for continuous rotation detection and reduced power consumption by switching power supply paths and using capacitors for instantaneous disconnection backup, ensuring the rotation detection function is maintained even when the vehicle's power supply voltage drops.
Implementation Method 1
The step-up power supply circuit is configured to perform a step-up operation so that a voltage of a DC power supply mounted in the vehicle is maintained at a normal level, when a vehicle power supply is turned on and the voltage of the DC power supply is lowered below the normal level
Implementation Method 2
The step-down power supply circuit is connected to the DC power supply and is configured to perform a step-down operation to a suitable voltage for operation of the rotation detection circuit
Implementation Method 3
The rotation detection circuit is configured to detect a rotation number of a motor that generates a torque applied to a steering mechanism of a vehicle, based on an electric signal. The electric signal is generated according to a rotation angle of the motor that is acquired through an in-vehicle sensor
Data Source
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AI summary
A rotation detection device includes a rotation detection circuit (74), a step-up power supply circuit (71), a step-down power supply circuit (73), a first power supply path (L1), and a second power supply path (L2). The rotation detection circuit is configured to detect a rotation number of a motor that generates a torque applied to a steering mechanism of a vehicle, based on an electric signal. The electric signal is generated according to a rotation angle of the motor that is acquired through an in-vehicle sensor (53).