Auxiliary Control Unit for Electric Power Tool Motor Safety
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Solution Overview
Problem
Existing power tools face mechanical and electronic failures due to high mechanical loads, leading to unsafe operating states, and current solutions like circuit breakers incur high costs and electrical losses, reducing battery life and generating waste heat.
Innovation Solution
An electric power tool with an auxiliary control unit independent of the motor control unit, which monitors the motor's operating state and switches it off if deviations occur, eliminating the need for circuit breakers and reducing energy losses by using a speed sensor for precise state detection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circuit breakers are used to ensure safety, then safety level is improved, but electrical losses increase and battery life decreases
Solution Approach 1:
The patent replaces the mechanical circuit breaker system with an electronic control system using semiconductor switches (MOSFETs or IGBTs) controlled by microcontrollers. This substitution eliminates the need for physical circuit breakers while maintaining safety through electronic monitoring and control, thereby reducing electrical losses and improving battery life.
Solution Approach 2:
The patent introduces an intermediary electronic control unit that acts as a mediator between the operating switch and the motor. This control unit continuously monitors the operating state and can interrupt power supply electronically, providing safety without the need for direct circuit breaker intervention, thus reducing energy losses.
2Reliability
If circuit breakers are used to ensure safety, then safety level is improved, but economic costs increase
Solution Approach 1:
The patent replaces expensive mechanical circuit breakers with more cost-effective electronic semiconductor switches and microcontrollers. This substitution reduces component costs while maintaining or improving safety functionality through electronic monitoring and control capabilities.
Solution Approach 2:
The electronic control unit serves multiple functions: it controls motor operation, monitors operating state, ensures safety compliance, and can implement various control strategies. This multi-functionality eliminates the need for separate circuit breaker components, reducing overall system cost and complexity.
3Reliability
If circuit breakers are used to ensure safety, then safety level is improved, but waste heat increases
Solution Approach 1:
The patent replaces mechanical circuit breakers with electronic semiconductor switches that have lower on-resistance and more efficient switching characteristics. This substitution reduces resistive losses and waste heat generation while maintaining safety through electronic control mechanisms.
4Reliability
If mechanical and electronic monitoring systems are added to ensure safety, then safety level is improved, but device complexity increases
Solution Approach 1:
The patent merges the safety monitoring functions with the existing motor control unit. The same microcontroller that controls motor operation also monitors operating state and ensures safety compliance, eliminating the need for separate safety monitoring hardware and reducing overall system complexity.
Solution Approach 2:
The control unit is designed to perform multiple functions: motor control, operating state monitoring, safety verification, and fault detection. This multi-functional design consolidates what would otherwise be separate systems, maintaining safety while minimizing added complexity.
Data Source
Figure 1
AI summary
The invention relates to an electric power tool (1) comprising an electric motor (M), a motor control unit (2) for operating the electric motor (M), an input interface (3) for inputting a target operating state (A) of the electric motor (M) into the motor control unit (2), and a motor sensor device (8) for detecting the operating state of the electric motor (M). An auxiliary control unit (9), independent of the motor control unit (2), is provided, which is communicatively connected to the motor sensor device (8) and to the input interface (3) and is configured to compare the operating state of the electric motor (M) detected by the motor sensor device (8) with the target operating state (A) entered via the input interface (3) and, in the event of a defined deviation of the operating state from the target operating state (A), to influence the operating state of the electric motor (M) by means of a control device (10).