Integrated Brushless Motor Control Module Thermal Management
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Solution Overview
Problem
Brushless DC (BLDC) motor controls in power tools face challenges with thermal management and wiring reliability due to heat generation by power switching components and susceptibility to dust and vibration in harsh environments, making it difficult to create a clean airflow for cooling and maintaining electrical connections.
Innovation Solution
An electronic module with a printed circuit board (PCB) housing high-side and low-side power switches forming an inverter bridge circuit, a heat sink system for thermal management, and positional sensors integrated on the PCB to provide rotational position signals, all integrated into a single module to reduce assembly complexity and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power switching components are used to drive BLDC motor, then motor control capability is improved, but heat generation increases making thermal management difficult
Solution Approach 1:
The patent combines the power switching components (MOSFETs), heat sinks, and control circuitry into a single integrated motor control module. This merging allows the heat-generating power components to be directly coupled with heat dissipation structures, improving thermal management while maintaining compact form factor suitable for cordless power tools.
Solution Approach 2:
The patent introduces heat sinks as intermediary thermal management components between the power switching components and the environment. These heat sinks act as thermal intermediaries that conduct heat away from the MOSFETs and dissipate it through extended surface area, enabling effective heat management in the integrated module.
2Ease of operation
If separate control hardware and wiring are used for micro-controller and power switches, then control functionality is achieved, but wiring complexity and susceptibility to failure increase
Solution Approach 1:
The patent integrates the micro-controller, power switching components, and their interconnections into a single motor control module. This consolidation eliminates the need for separate wiring between discrete control hardware and power switches, reducing wiring complexity and potential failure points while maintaining full control functionality.
Solution Approach 2:
The integrated motor control module serves multiple functions simultaneously: it houses the micro-controller for control logic, power switching components for motor drive, heat sinks for thermal management, and provides structural mounting. This multi-functionality reduces the need for separate components and wiring harnesses.
3Ease of operation
If traditional separate module assembly is used, then component functionality is achieved, but assembly complexity and reliability in harsh environments decrease
Solution Approach 1:
The patent merges all critical components (control circuitry, power switches, heat sinks, and mounting structures) into a single integrated motor control module. This integration reduces the number of external connections and interfaces that could fail due to vibration and dust, improving reliability in harsh power tool environments while maintaining all necessary functionalities.
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 and reduces wiring burdens, enhancing the reliability and efficiency of BLDC motor control in power tools by integrating power and control components on a single PCB with an efficient heat transfer system and positional sensors, improving performance in harsh environments.
Implementation Method 1
a second heat sink secured to the module housing in thermal communication with the first heat sink to transfer heat from the first power switches
Data Source
AI summary
A power tool including an electric motor is provided. The tool includes a substantially disc-shaped printed circuit board (PCB), power switches mounted on the PCB; magnetic sensors mounted on the PCB facing the motor; a heat sink in thermal communication with the power switches disposed between the PCB and the electric motor; and a molded casing structurally securing the heat sink relative to the PCB. The molded casing includes a center opening, at least one first opening provided at a first radial distance from the center opening arranged to receive the magnetic sensors therein, and at least one second opening provided at a second radial distance from the center opening arranged to securely receive the heat sink therein.