Power Tool Switch Module With H-Bridge PWM Heat Reduction
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Solution Overview
Problem
Conventional power tool switch modules require significant space due to mechanical components, are prone to wear and tear, and generate excessive heat, contributing to increased size and weight.
Innovation Solution
An electronic switch module integrating a user-actuated input unit, control unit, and power components in a single housing, utilizing a programmable micro-controller for control and synchronous rectification with H-bridge FETs to manage power distribution, eliminating mechanical switches and reducing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical switches and components are used in the switch module, then the tool can be controlled for direction and speed, but the size and weight of the tool increase significantly
Solution Approach 1:
The patent replaces mechanical switches with electronic switching components including field effect transistors (FETs), integrated circuits, and microcontrollers. These electronic components perform the same control functions (direction, speed, on/off) as mechanical switches but with significantly reduced weight and size, eliminating moving parts and mechanical wear while maintaining full operational control capability
Solution Approach 2:
The patent integrates multiple control functions into a single electronic control module that combines on/off switching, variable speed control, and forward/reverse direction control. This multi-functional integration eliminates the need for separate mechanical switches for each function, reducing overall component count, weight, and complexity while preserving all necessary control capabilities
2Ease of operation
If mechanical components are used in the switch module, then the tool can be operated and controlled, but the durability decreases due to wear and tear
Solution Approach 1:
The patent replaces all mechanical switching components with solid-state electronic components including FETs, integrated circuits, and microcontrollers. These electronic components have no moving parts, eliminating mechanical wear and tear entirely. The electronic switches provide the same control functions (on/off, variable speed, forward/reverse) with significantly enhanced durability and reliability, as they are not subject to friction, contact erosion, or mechanical fatigue
3Power
If conventional power components are used, then power can be supplied to the motor, but excessive heat is generated
Solution Approach 1:
The patent replaces conventional power components with advanced electronic switching components including field effect transistors (FETs) and integrated circuits designed for efficient power conversion. These components have lower on-resistance and higher switching efficiency, reducing I²R losses and minimizing heat generation. The electronic control enables precise PWM modulation for efficient motor power delivery while maintaining lower operating temperatures compared to conventional mechanical contactors and resistive control methods
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 reduces the size and weight of power tools by minimizing heat generation and mechanical components, enhancing durability and efficiency through synchronous rectification and IMS board usage.
Implementation Method 1
A set of sense magnets coupled to the PMs in the rotor assembly are sensed by a sensor, such as a Hall Effect sensor, to identify the current position of the rotor assembly
Implementation Method 2
power components arranged to modulate a supply of power from the input power pins to the output power pins
Data Source
AI summary
A power tool includes a motor, a power interface facilitating a connection to a power source, semiconductor switches configured as a bridge circuit to modulate a supply of power from the power interface to the motor, an input unit configured to output a variable-voltage signal based on a position of a trigger switch, and a controller. The controller control the supply of power to the electric motor by applying a pulse-width modulated (PWM) signal to a first semiconductor switch and applying a synchronously-rectified signal to a second semiconductor switch based on the variable-voltage signal.