Cleaner Motor PCB Layout for Airflow Cooling and EMI Isolation
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Solution Overview
Problem
Handheld vacuum cleaners face issues with excessive heat generation in circuit elements due to high current flow and increased motor rotation velocity, leading to stability and reliability concerns, as well as electromagnetic interference (EMI) noise affecting control signals.
Innovation Solution
A motor driving apparatus with a printed circuit board design where heat-generating elements are mounted on one surface facing the air flow path to dissipate heat effectively, and signal and power lines are electrically disconnected to minimize EMI noise impact on control signals by positioning grounds on different layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the capacity of the inverter is increased to improve suction force, then the motor rotation velocity increases, but excessive heat generation of circuit elements occurs due to high current flow
Solution Approach 1:
The patent applies local quality by positioning heat-generating circuit elements (switching elements and shunt resistor) in a specific area of the printed circuit board that corresponds to the air flow path from the impeller. This localized placement ensures that heat is dissipated efficiently in the regions where it is generated, while other areas of the PCB can be optimized for different functions.
Solution Approach 2:
The patent utilizes the air flow generated by the impeller as a cooling medium. The air flow path is designed to pass through or over the area where heat-generating elements are mounted, using the moving air to convectively cool the circuit elements and prevent excessive heat accumulation.
2Speed
If the motor rotation velocity is increased to improve suction force, then the switching frequency of switching elements increases, but electromagnetic interference (EMI) noise is generated affecting control signals
Solution Approach 1:
The patent segments the printed circuit board into distinct functional areas: a first area for mounting heat-generating switching elements, a second area for mounting control circuit elements, and a third area for mounting power consumption elements. This spatial segmentation isolates EMI-prone components from sensitive control circuits, reducing electromagnetic interference.
Solution Approach 2:
The patent extracts or separates the control circuit elements from the heat-generating switching elements by placing them in different areas of the PCB. The control circuit elements are positioned in a second area that is spatially separated from the first area where switching elements are mounted, thereby removing the control circuits from the high-EMI environment.
3Power
If heat-generating elements are mounted on the printed circuit board, then the inverter capacity increases, but the elements are damaged due to excessive heat accumulation
Solution Approach 1:
The patent utilizes the third dimension (air flow direction) to solve the heat dissipation problem. By orienting the heat-generating elements perpendicular to the air flow path and positioning them in the flow path area, the design creates effective convective cooling without increasing the physical footprint of the PCB or adding active cooling 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 design effectively dissipates heat and reduces EMI noise, enhancing the stability and reliability of the handheld vacuum cleaner by optimizing the placement of circuit elements and isolating signal and power lines.
Implementation Method 1
a flow path of air circulated by the impeller
Implementation Method 2
effectively dissipating heat generated by circuit elements mounted on the printed circuit board
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A motor driving apparatus for a cleaner includes a DC terminal capacitor, an inverter including switching elements configured to convert the DC power into AC power, a motor configured to operate the inverter, an impeller connected to the motor and configured to circulate air, and a printed circuit board having a first surface that mounts the switching elements and faces toward the motor and the impeller, and a second surface that mounts the DC terminal capacitor. The printed circuit board includes circuit elements mounted on a first area of the first surface and configured to carry a current having a level greater than or equal to a predetermined level. The first area is positioned in a flow path of the air circulated by the impeller.