BLDC Power Module PCB Layout for Compact Heat Dissipation

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Solution Overview

Problem

Conventional cordless power tools with BLDC motors face challenges in high-power applications due to excessive heat generation and the need for larger motors, which complicates cooling in dusty environments and conflicts with ergonomic compactness.

Innovation Solution

A power module for BLDC motors featuring a thermally-conductive core carrier layer with etched electrically-insulating layers, a clamping heat sink, and strategically positioned positional sensors, which enhances heat dissipation and compactness while maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional power components are used to drive BLDC motors in high power applications, then power output is improved, but heat generation increases excessively

Engineering Contradiction:

Improvepower outputVSAvoidheat generation

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent combines the power circuit board and sensor board into a single integrated module with a unified circuit board structure. This integration allows for optimized thermal management by consolidating heat-generating components and sensors in a coordinated arrangement, enabling more effective heat dissipation pathways while maintaining compact high-power operation

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements localized thermal management by positioning thermal vias, heat sinks, and cooling channels specifically at high-heat-generation zones on the circuit board. The circuit board design includes varied thermal conductivity regions tailored to local heat loads, with enhanced cooling provisions directly beneath power switches and motor driver components

Inventive Principle:

Principle #3Local quality

2Power

If larger motors are used for high power applications, then power output is improved, but device size increases

Engineering Contradiction:

Improvepower outputVSAvoidmotor size

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent employs advanced circuit board parameters and materials to increase power density without proportionally increasing motor size. By optimizing copper trace thickness, layer configuration, and thermal via density, the system achieves higher power handling capability in a compact form factor, allowing high-power output from smaller motor dimensions

Inventive Principle:

Principle #35Parameter changes

3Temperature

If cooling systems are enhanced for high power applications, then heat dissipation is improved, but device complexity increases in dusty environments

Engineering Contradiction:

Improveheat dissipationVSAvoidcooling system complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent implements self-cooling mechanisms where the motor's own operation generates airflow that passes through the circuit board's internal cooling channels. The design utilizes the motor's rotational airflow to naturally cool the power electronics without requiring separate active cooling systems, reducing complexity while maintaining effective heat dissipation in dusty environments

Inventive Principle:

Principle #25Self-service

4Volume of moving object

If integrated power and sensor modules are used, then device compactness is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvemodule sizeVSAvoidassembly precision

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent segments the integrated module into distinct functional zones on the circuit board, with separate areas for power switching, sensor mounting, and thermal management. This zonal segmentation allows each section to be optimized and assembled independently with standard tolerances, reducing overall manufacturing precision requirements while maintaining compact integration

Inventive Principle:

Principle #1Segmentation

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 manages heat dissipation and reduces motor size, enabling high-power performance in compact cordless tools without compromising reliability in dusty environments.

Implementation Method 1

The circuit board includes a thermally-conductive core carrier layer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a clamping heat sink having a main body disposed over the power switches and legs extending around the power circuit board and mounted to the motor

Methodology Applied

Scientific EffectHeat sink: Heat Sink

Data Source

PatentUS11811293B2Power module for a brushless motor in a power tool

Publication Date: 2023.11.07 BLACK & DECKER CORP

AI summary

A power module for driving a motor is provided including a power circuit board, power switches operatively connected to the motor disposed on a first side of the circuit board, and positional sensors disposed on a side surface of the power circuit board facing the motor. The power circuit board includes a thermally-conductive core carrier layer, a first electrically-insulating layer disposed on a first surface of the core carrier layer and on which the power switches are mounted, and a second electrically-insulating layer disposed on a second surface of the core carrier layer and on which the positional sensors are mounted. The second electrically-insulating layer is etched to expose the conductive core layer on at least approximately 70% of a surface area of the second side of the circuit board.