Steering Control Device Voltage Drop Recovery
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Solution Overview
Problem
Electric power steering systems (EPS) face issues with temporary drops in vehicle battery voltage, leading to premature shutdown of pre-drivers, which can result in failure to resume power supply to the motor when the voltage recovers, affecting steering assistance.
Innovation Solution
A steering control device with a conversion circuit, drive circuit, and control circuit that detects voltage drops, resets the drive circuit to an initial state, and re-initializes it when the voltage recovers, ensuring the motor resumes operation when the battery voltage returns to normal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pre-driver stops operating when a drop in supply voltage is detected, then the system responds to voltage abnormalities, but the motor cannot resume operation when the voltage recovers from a temporary drop
Solution Approach 1:
The control circuit performs preliminary initialization of the drive circuit before voltage drops occur. When a temporary voltage drop happens, the pre-driver stops operation, but the control circuit maintains the initialized state and quickly re-initializes the drive circuit upon voltage recovery, enabling the motor to resume operation without delay
Solution Approach 2:
The system implements feedback by monitoring the supply voltage continuously and using this information to control the initialization state of the drive circuit. When voltage recovers from a temporary drop, the feedback signal triggers the control circuit to re-initialize the drive circuit, restoring motor operation
2Productivity
If the drive circuit is initialized to enable motor operation, then the motor can run smoothly, but the system cannot respond to voltage drops by stopping operation
Solution Approach 1:
The initialization state of the drive circuit is made dynamic rather than fixed. The control circuit can switch between initialized and non-initialized states based on real-time voltage conditions, allowing the system to adapt between motor operation and voltage abnormality response as 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 the EPS to effectively handle temporary voltage drops by resuming motor operation when the battery voltage recovers, ensuring continuous steering assistance.
Implementation Method 1
a conversion circuit that converts direct current power supplied from a direct current power supply mounted in the vehicle to alternating current power supplied to the motor
Data Source
AI summary
A steering control device capable of suitably handling a temporary drop in a supply voltage of a vehicle is provided. An ECU includes a microcomputer, a pre-driver, and an inverter. The microcomputer generates a command signal for the pre-driver. Upon being initialized by the microcomputer, the pre-driver becomes operable to generate a drive signal for the inverter based on the command signal. The inverter converts direct current power supplied from a battery into alternating current power for a motor by operating based on the drive signal. When a drop in a voltage of the battery is detected, the pre-driver transmits an abnormal-condition detection signal to the microcomputer and stops operating by resetting a state of the pre-driver to an initial state where the pre-driver is not initialized yet. When the abnormal-condition detection signal is received, the microcomputer re-initializes the pre-driver.