Hall Sensor Ground Pattern for EMI-Resistant Motor Position Detection
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Solution Overview
Problem
Magnetic elements in motor systems are vulnerable to electromagnetic interference (EMI) and electrostatic discharge (ESD), leading to potential failure during testing.
Innovation Solution
A ground pattern corresponding to the Hall integrated circuit (IC) is formed on a substrate to reduce the likelihood of failure due to EMI or static electricity, incorporating a first and second ground pattern connected to the Hall and encoder signal magnetic elements respectively, enhancing electromagnetic interference shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic elements are mounted on a printed circuit board and disposed in a housing, then the rotor position detection function is achieved, but the system becomes vulnerable to electromagnetic interference and electrostatic discharge
Solution Approach 1:
A ground pattern is introduced as an intermediary element between the Hall IC and the external environment. This ground pattern acts as a mediator that intercepts and redirects electromagnetic interference and electrostatic discharge away from the sensitive magnetic elements, thereby protecting the rotor position detection system without requiring changes to the fundamental mounting structure
Solution Approach 2:
The invention utilizes the harmful electromagnetic interference and electrostatic discharge energy by providing a controlled path through the ground pattern. Instead of allowing these harmful factors to directly affect the magnetic elements, the ground pattern channels the interference energy to a safe discharge path, effectively converting the harmful effect into a controlled phenomenon that does not compromise system reliability
2Object-affected harmful factors
If a ground pattern corresponding to the Hall IC is formed on the substrate, then electromagnetic interference shielding is improved, but the device complexity increases
Solution Approach 1:
The ground pattern is applied locally and specifically to the Hall IC mounting area rather than requiring a comprehensive grounding system across the entire substrate. This localized approach provides effective EMI shielding for the critical magnetic elements while minimizing the additional complexity introduced to the overall device structure
Solution Approach 2:
The invention implements a partial grounding solution that focuses specifically on the critical Hall IC region rather than providing complete grounding for the entire circuit board. This partial action is sufficient to protect the rotor position detection function while avoiding the excessive complexity that would result from comprehensive grounding of all components
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
The solution effectively reduces the possibility of EMI and electrostatic failure in motor systems, improving the reliability of rotor position detection and overall motor performance.
Implementation Method 1
A sensor including a magnetic element is disposed inside the motor as a rotor position detecting apparatus. The sensor grasps a present position of the rotor by detecting a magnetic force of the sensing magnet installed to be rotatable in conjunction with the rotor.
Implementation Method 2
A ground pattern corresponding to a Hall integrated circuit (IC) is formed on a substrate to reduce a possibility of failure due to electromagnetic interference (EMI) or static electricity
Data Source
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Figure 2
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AI summary
An embodiment of the present invention relates to a rotor position detecting apparatus and a motor and a motor-driven steering apparatus comprising same, the rotor position detecting apparatus comprising: a substrate, a magnetic Hall-signal element mounted on the substrate, and a first ground pattern disposed on one side of the substrate and electrically connected to the magnetic Hall-signal element. As a result, the motor can reduce probability of faults due to electromagnetic waves or static electricity.