Drone Controller PCB EMI Shielding Design
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Solution Overview
Problem
Existing drone controllers integrated into a single PCB face challenges in reducing the risk of failures due to electromagnetic interferences (EMI) from BLDC motor switching and current sensing, which is particularly problematic in small drones used in drone swarms.
Innovation Solution
The drone controller is designed on a multi-layer printed circuit board (PCB) with a central area housing the microcontroller and sensory units, shielded from the motor controllers and power transistors by metallization areas. This configuration includes field-oriented motor controllers with power transistors arranged in pairs across different layers, along with buffer capacitors and differential current sensing traces to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If all components are integrated on a single PCB to reduce size and weight, then device compactness is improved, but electromagnetic interference from motor switching increases and reliability deteriorates
Solution Approach 1:
The PCB is divided into distinct functional zones: a central sensitive components area housing the microcontroller and sensors, and peripheral motor control areas with power transistors. This spatial segmentation isolates EMI-generating components from sensitive components while maintaining single-PCB integration, thus preserving weight advantages while improving reliability.
Solution Approach 2:
Ground contacts and metallization areas act as intermediary shielding structures between the motor controllers and the central sensitive components. These intermediary elements block electromagnetic interference paths, allowing integrated design without compromising reliability.
2Area of stationary object
If power transistors are placed close to motor controllers for compact design, then PCB area is reduced, but electromagnetic interference increases and reliability decreases
Solution Approach 1:
Different regions of the PCB are assigned different functional qualities: the central area is optimized for low-EMI sensitivity with the microcontroller and sensors, while peripheral areas accommodate high-power motor controllers and transistors. This local quality differentiation allows compact overall design while protecting sensitive areas from EMI.
Solution Approach 2:
The layout utilizes multi-layer PCB architecture, arranging components and routing signals across different vertical layers. This dimensional approach allows power transistors to be positioned close to motor controllers on one layer while shielding sensitive components on adjacent layers, reducing EMI exposure while maintaining compact footprint.
3Use of energy by moving object
If high current signals are switched quickly for efficient motor control, then power efficiency is improved, but electromagnetic interference increases and causes failures
Solution Approach 1:
The ground contacts and shielding metallization are strategically positioned to convert the harmful EMI from fast switching into a contained electromagnetic field that is directed away from sensitive components. The shielding structures transform potential interference into controlled electromagnetic containment, maintaining switching efficiency while preventing failure.
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 reduces the risk of failures in drone controllers by isolating sensitive components from EMI, allowing for reliable operation even in high-interference environments like drone swarms, and enabling the delivery of high currents without cooling.
Implementation Method 1
The motor controllers have corresponding sets of power transistors for driving brushless direct current motors
Implementation Method 2
Said central area of the printed circuit board is at least partly surrounded by metallization areas (that can be used for delivering power supply) and ground contacts separating it from the power transistors and the motor controllers
Implementation Method 3
Power supply ports of the components provided in the central area are protected with power supply filters
Implementation Method 4
The motor controllers are provided with engine current sensing resistors
Data Source
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AI summary
A drone controller realized on a printed circuit board (PCB) comprising a system on chip microcontroller (SoC) and field-oriented controllers (FOC) connected thereto, wherein the motor controllers (FOC) have corresponding sets of power transistors (T) for brushless direct current motors, according to the invention is integrated in a single printed circuit board (PCB) being multilayer printed circuit board (PCB) having at least three layers. Power transistors (T) are arranged in proximity of edges of the printed circuit board (PCB), and have control resistors configured so that rising time when switching the transistor (T) is greater than 0.5 µs. The printed circuit board (PCB) has a central area comprising sensory and digital circuitry. Said central area of the printed circuit board (PCB) is at least partly surrounded by metallization areas (GA) separating it from the power transistors (T) and the motor controllers (FOC). A power supply for components arranged in said central area is provided on a layer of the printed circuit board (PCB) shielded from both sides by metallization provided on the other layers, power supply ports of the components provided in the central area are protected with power supply filters.