Electronic Parking Brake Motor Lock Detection Using Back-EMF
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Solution Overview
Problem
Existing electronic parking brake systems rely on current sensors to detect motor lock failures, which can lead to increased manufacturing costs and difficulty in miniaturization, and may fail to detect motor lock when the current sensor itself fails.
Innovation Solution
The system employs a controller that detects back electromotive force (EMF) of the electric motor during a motor lock inspection mode to determine lock failures, eliminating the need for a current sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current sensor is used to detect motor lock, then motor lock detection capability is provided, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent extracts the motor lock detection function from the current sensor and relocates it to the controller by utilizing back electromotive force detection. This removes the need for the current sensor while maintaining the detection capability, thereby reducing device complexity and manufacturing cost.
Solution Approach 2:
The motor itself provides the detection signal through its back electromotive force during operation. The controller utilizes this self-generated signal to detect motor lock conditions, eliminating the need for external sensing components and simplifying the overall system.
2Reliability
If a current sensor is used to detect motor lock, then motor lock detection capability is provided, but manufacturing cost increases
Solution Approach 1:
The patent removes the current sensor component from the system and transfers its detection function to the controller. This reduction in component count directly lowers manufacturing costs while preserving the essential motor lock detection capability through back electromotive force monitoring.
Solution Approach 2:
The patent replaces the expensive current sensor with a software-based detection method using existing controller resources. This substitution uses readily available controller processing capabilities instead of costly hardware sensors, significantly reducing manufacturing expenses.
3Reliability
If a current sensor is used, then motor lock detection is possible, but product miniaturization becomes difficult
Solution Approach 1:
The patent extracts and removes the current sensor component from the system architecture. By transferring the detection function to the controller through back electromotive force analysis, the physical space required for sensing is eliminated, enabling more compact product design and easier miniaturization.
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 allows for reliable detection of motor lock failures without relying on current sensors, enabling miniaturization and cost reduction while ensuring accurate detection of motor lock conditions.
Implementation Method 1
the controller is configured to detect a back electromotive force of the electric motor in a motor lock inspection mode for inspecting a lock failure of the electric motor
Data Source
AI summary
Disclosed is an electronic parking brake system including a piston provided to press a pair of brake pads disposed on opposite sides of a brake disk rotating together with a wheel of a vehicle, a nut member provided to press the piston, a spindle member provided to move the nut member, an electric motor provided to rotate the spindle member, an H-bridge having a pair of high-side switching elements and a pair of low-side switching elements to rotate the electric motor in a forward or backward direction, and a controller electrically connected to the H-bridge, wherein the controller is configured to detect a back electromotive force of the electric motor in a motor lock inspection mode for inspecting a lock failure of the electric motor and determine the lock failure of the electric motor based on a change in the detected back electromotive force.