Motor Driver Board Grounding for Power Tool EMI Reduction
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Solution Overview
Problem
Existing power tools face challenges in reducing radiated interference from electric motors without occupying additional space or increasing costs, as external magnetic rings or capacitors are used for interference reduction.
Innovation Solution
The stator assembly of the electric motor is directly connected to a metal base layer within the power tool's driver board via a wire, eliminating the need for external noise suppression devices and optimizing the motor's interference reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external magnetic ring or capacitor is used to reduce radiated interference, then interference reduction is achieved, but space inside the power tool is occupied and cost increases
Solution Approach 1:
The patent merges the noise suppression function into the existing driver board by directly connecting the stator assembly to the metal base layer. This integration eliminates the need for separate external magnetic rings or capacitors, thereby reducing space occupation while maintaining interference reduction capability.
Solution Approach 2:
The driver board's metal base layer serves dual purposes: it provides structural support for the circuit board and simultaneously acts as a ground reference for noise suppression. This self-service approach allows the existing component to perform multiple functions without adding extra parts.
2Object-affected harmful factors
If external magnetic ring or capacitor is used to reduce radiated interference, then interference reduction is achieved, but cost increases
Solution Approach 1:
The patent combines the ground connection function with the existing driver board structure by directly connecting the stator assembly to the metal base layer. This eliminates the need to purchase and install separate external noise suppression components, thereby reducing manufacturing cost while maintaining interference reduction effectiveness.
Solution Approach 2:
The driver board's metal base layer is utilized as a ground reference, allowing the existing component to serve dual purposes. This approach eliminates the need for additional expensive external components and reduces overall manufacturing cost.
3Volume of stationary object
If stator assembly is directly connected to metal base layer, then space occupation is reduced and cost is lowered, but radiated interference reduction effectiveness must be maintained
Solution Approach 1:
The patent integrates the ground connection function directly into the driver board's metal base layer, eliminating the need for external noise suppression components. This direct connection maintains effective radiated interference reduction while minimizing space occupation.
Solution Approach 2:
The metal base layer of the driver board serves as an intermediary ground reference that provides effective noise suppression. By using this existing conductive layer as the grounding path, the patent achieves interference reduction without adding external 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
This approach effectively reduces radiated interference while minimizing space occupation and costs, achieving superior interference suppression compared to using external devices.
Implementation Method 1
the stator assembly is directly connected to the metal base layer by a wire... to reduce the radiated interference of the electric motor
Data Source
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AI summary
A power tool includes a housing; an energy storage device configured to supply power to the power tool; an electric motor disposed in the housing and including a stator assembly and a rotor assembly; a driver board including a circuit layer, an insulating layer, and a metal base layer, where multiple semiconductor switches are disposed on the circuit layer, and a driver circuit formed by the multiple semiconductor switches is electrically connected to the energy storage device; and a controller configured to control the multiple semiconductor switches to be turned on and off to adjust power supply from the energy storage device to the electric motor; where the stator assembly is directly connected to the metal base layer by a wire.