Electric Motor Stator Shielding for Electromagnetic Interference
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Solution Overview
Problem
Electronically commutated electric motors in air blower devices for motor vehicles face challenges in minimizing the propagation of electromagnetic waves outside the device, which can interfere with nearby electronic devices.
Innovation Solution
The motor incorporates a stator connected to a metallic support grounded electrically, with conductive screens extending between stator teeth to form an electromagnetic shield, confining electromagnetic fields within the device. These screens are designed to limit electromagnetic radiation propagation both radially and axially, ensuring effective containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current switching is performed in the stator coils to generate electromagnetic waves for motor operation, then the motor achieves rotational movement and operational functionality, but electromagnetic waves propagate outside the device and disturb nearby electronic devices
Solution Approach 1:
A conductive screen is introduced as an intermediary element between the stator coils and the external environment. The screen is electrically connected to the grounded support means, creating a shield that intercepts and redirects electromagnetic waves, preventing them from propagating outside the device while allowing the motor to operate normally
Solution Approach 2:
The conductive screen utilizes the electromagnetic waves generated by the stator coils and redirects them back toward the stator rather than allowing external propagation. By connecting the screen to the grounded support means, the system converts the harmful electromagnetic radiation into a beneficial shielding effect that confines energy within the device
2Object-generated harmful factors
If a conductive screen is added to shield electromagnetic waves, then electromagnetic radiation is confined within the device, but the device structure becomes more complex
Solution Approach 1:
The conductive screen is merged with the existing support means structure. The support means is designed to provide both mechanical support for the stator and electrical grounding for the screen, combining structural and electromagnetic shielding functions into a single integrated component, thereby minimizing additional complexity
Solution Approach 2:
The support means serves multiple functions: it provides mechanical support for the stator, acts as an electrical ground connection, and serves as the mounting structure for the conductive screen. This multi-functionality reduces the need for separate components and simplifies the overall device structure
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 confines electromagnetic fields within the air blower device, reducing interference with other electronic systems and ensuring optimal operation while maintaining the motor's efficiency.
Implementation Method 1
at least one screen is electrically connected to the support means, said at least one screen comprising closure means which extend along the longitudinal axis to fill at least one of said passage zones between two teeth of the stator
Implementation Method 2
This arrangement allows the formation of a conductive enclosure connected to the electrical ground, and therefore maintained at a fixed potential, so as to form an electromagnetic shield capable of confining inside the air blower device the electric field created by current switching in the stator coils
Data Source
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Figure 8~9
AI summary
An air-pulsation device according to the invention comprises an electric motor (2) having a rotor and a stator (14). The stator has teeth arranged such that a passage zone (30) for winding a coil is formed between two adjacent teeth. The stator is in contact with a metallic support means for the electric motor, which is electrically connected to an electrical ground. At least one screen (50) is electrically connected to the support means, said at least one screen having closing means (62, 68) that extend axially to fill at least one of said passage zones between two teeth of the stator (14).