Motor Drive Control for EPS Battery Power Reduction
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Solution Overview
Problem
Existing motor drive control systems for electric power steering consume excessive battery power when detecting motor rotation information during the OFF state of the ignition switch, as they continuously supply power during angle changes, leading to high power consumption.
Innovation Solution
A motor drive control apparatus with a ring-shaped or disk-shaped magnet and a rotation information detection function unit that intermittently supplies power at varying intervals based on the motor rotation speed, reducing power consumption while maintaining detection accuracy by adjusting the power supply interval according to the motor's rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is continuously supplied to the rotation information detection function unit when angle changes are detected, then detection reliability is improved, but battery power consumption increases
Solution Approach 1:
The power supply interval is dynamically adjusted based on motor rotation speed. When rotation speed is high (indicating active steering operation), power is supplied more frequently to ensure detection reliability. When rotation speed is low, power supply interval increases to reduce consumption. This dynamic adaptation resolves the contradiction between maintaining reliability and reducing energy use.
Solution Approach 2:
The patent changes the power supply parameter (interval duration) based on operating conditions. By monitoring motor rotation speed and adjusting the power supply interval accordingly, the system optimizes the balance between detection reliability and power consumption. This parameter adjustment directly addresses the technical contradiction.
2Use of energy by moving object
If power is intermittently supplied at long intervals to reduce power consumption, then battery power consumption decreases, but detection accuracy during fast rotation deteriorates
Solution Approach 1:
The system dynamically adjusts the power supply interval based on real-time motor rotation speed detection. When fast rotation is detected, the interval shortens to capture position changes accurately. When rotation is slow, the interval lengthens to save power. This dynamic response prevents deterioration of detection accuracy during fast rotation while maintaining low power consumption during normal operation.
Solution Approach 2:
The system uses feedback from rotation speed monitoring to control power supply timing. The rotation information detection function unit detects motor rotation speed, and this information feeds back to the power supply control logic, which adjusts the power supply interval accordingly. This feedback mechanism ensures detection accuracy is maintained during fast rotation while optimizing power consumption.
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 approach reduces battery power consumption while ensuring reliable steering assistance control by optimizing power supply intervals based on motor rotation speed, effectively managing power usage during both slow and fast rotational changes.
Implementation Method 1
a rotational position information detector that detects a magnetic flux of the magnet as rotational position information
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
Provided is a motor drive control apparatus, an electric power steering apparatus, and a vehicle suitable for reducing a battery power consumption for detecting motor rotation information during an OFF state of an ignition switch. The motor drive control apparatus includes first and second rotation information detection function units (51 and 52) and a power control unit (50). When it is determined that the ignition switch is changed from the ON state to the OFF state, the power control unit (50) intermittently supplies power from a battery to the first and second rotation information detection function units (51 and 52) at a first interval while a motor rotation number is lower than a preset rotation number set in advance. When it is determined that the motor rotation number becomes equal to or higher than the preset rotation number during this intermittent supply state, the power control unit (50) intermittently supplies the power from the battery to the first and second rotation information detection function units (51 and 52) at a second interval shorter than the first interval while the motor rotation number is equal to or higher than the preset rotation number.