Brushless DC Motor Overcurrent Fuse Integration
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Solution Overview
Problem
Conventional brushless DC motors lack effective overcurrent protection mechanisms, leading to potential overheating and damage from short circuits, and existing overcurrent fuses have production variations that affect motor performance.
Innovation Solution
Integration of an overcurrent fuse within the control circuit of a brushless DC motor, which measures current flow and interrupts voltage supply when a predetermined value is exceeded, using a device that corrects for impedance variations through data storage and computation, preventing windings and switches from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional overcurrent fuses are used without integration, then overcurrent protection is provided, but production variations in impedance affect motor performance
Solution Approach 1:
The overcurrent fuse is integrated directly into the control circuit board, merging the protection function with the control system. This integration eliminates separate fuse mounting and reduces impedance variations caused by external connections, while maintaining reliable overcurrent protection through the fused electrically conductive material.
Solution Approach 2:
The patent specifies precise parameter ranges for the overcurrent fuse including resistance (0.01-10 milliohms), maximum current (10-1000 Amperes), and fusing current (1.1-2.0 times maximum current). By controlling these parameters within tight tolerances, the invention compensates for production variations and ensures consistent motor performance across different manufacturing batches.
2Reliability
If overcurrent protection is added to brushless DC motors, then damage from short circuits is prevented, but device complexity increases
Solution Approach 1:
The overcurrent fuse is integrated directly into the control circuit board, merging the protection function with the control system. This eliminates the need for separate protective devices and reduces overall system complexity while maintaining reliable overcurrent protection.
Solution Approach 2:
The control circuit board serves multiple functions: it provides motor control, houses the overcurrent fuse for protection, and integrates the measuring device for current detection. By making the control circuit multi-functional, the patent avoids adding separate dedicated protection circuits, thereby maintaining simplicity while achieving comprehensive protection.
3Measurement precision
If measuring device uses voltage drop across overcurrent fuse, then current flow is detected, but impedance variations affect measurement precision
Solution Approach 1:
The patent specifies precise parameter ranges for the overcurrent fuse including resistance (0.01-10 milliohms) and fusing current (1.1-2.0 times maximum current). By controlling these parameters within tight tolerances, the invention minimizes the impact of impedance variations on voltage drop measurements, ensuring accurate current detection.
Solution Approach 2:
The measuring device continuously monitors the voltage drop across the overcurrent fuse and uses this information to detect current flow and trigger protection when necessary. This feedback mechanism compensates for minor impedance variations by dynamically adjusting the measurement threshold based on actual operating conditions.
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 provides reliable overcurrent protection, preventing overheating and subsequent damage, while accounting for production variations in impedance, ensuring consistent motor performance and safety.
Implementation Method 1
A fuseable electrically conductive material, which heats up as an electrical current flows owing to the electrical resistance of said material, is arranged between two holders.
Implementation Method 2
A fuseable electrically conductive material, which heats up as an electrical current flows owing to the electrical resistance of said material, is arranged between two holders.
Implementation Method 3
whereby a voltage drop across the overcurrent fuse can be supplied to the measuring device as an input value
Data Source
AI summary
A brushless DC motor having a plurality of electrical windings and a control circuit operatively connected thereto. The control circuit includes a plurality of switches configured for a time-dependent application of an electrical voltage from an external voltage supply to the windings. A measuring device is also provided for generating an electrical signal depending on the current flow IB from the external voltage supply through the control circuit. An overcurrent fuse is further provided for protecting the control circuit and the windings. In order to achieve particularly high integration of the control circuit, the invention proposes supplying a voltage drop across the overcurrent fuse to the measuring device as an input value.