Brushless DC Motor Temperature Detection Using Self-Service Resistance Elements
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Solution Overview
Problem
Conventional brushless DC motors face reliability and cost issues due to the increased number of circuit components required for temperature detection, hindering cost reduction and downsizing.
Innovation Solution
A brushless DC motor design that incorporates temperature-sensitive resistance elements to detect temperature rises and reduce voltage, eliminating the need for a special temperature determination unit, thereby enhancing reliability and achieving cost reduction and downsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a special temperature determination unit is used to detect temperature rises, then temperature detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses temperature-sensitive resistance elements that are already present in the motor system (for other functions) to detect temperature rises. These elements serve dual purposes: their original function plus temperature detection, eliminating the need for separate temperature sensing components. This self-service approach reduces device complexity while maintaining temperature detection capability.
Solution Approach 2:
The patent makes existing circuit components perform multiple functions. The resistance elements in the motor circuit are utilized for both their original purpose and temperature detection. By making components universal, the system avoids adding dedicated temperature determination units, thus reducing overall device complexity while achieving accurate temperature monitoring.
2Reliability
If multiple circuit components are added for temperature detection, then temperature monitoring capability is improved, but manufacturing cost increases
Solution Approach 1:
The existing resistance elements in the motor system perform temperature detection as a secondary function. Since these elements are already part of the standard motor construction, utilizing them for temperature monitoring avoids additional component costs and reduces manufacturing complexity while improving temperature monitoring capability and overall reliability.
Solution Approach 2:
The patent implements multi-functionality in existing components, particularly the resistance elements that serve both their original circuit function and temperature sensing. This approach eliminates the need for separate temperature sensing components, thereby reducing part counts, lowering manufacturing costs, and simplifying assembly processes while enhancing temperature monitoring reliability.
3Reliability
If the number of circuit components is increased for temperature detection, then temperature control reliability is improved, but device downsizing is hindered
Solution Approach 1:
The patent leverages existing resistance elements within the motor system to provide temperature detection functionality. By making these existing components serve dual purposes, the system achieves reliable temperature control without adding extra components, thereby maintaining compact size and avoiding the downsizing issues that would result from adding dedicated temperature sensing circuits.
Solution Approach 2:
The implementation of multi-functional components, particularly using existing resistance elements for both circuit operation and temperature sensing, allows the system to achieve reliable temperature control without increasing component quantity. This approach maintains device compactness and avoids the size and complexity penalties associated with adding dedicated temperature determination units.
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 prevents temperature rises in stator windings without a special temperature determination unit, improving reliability and enabling cost-effective and compact motor designs for applications like ventilating air blowers.
Implementation Method 1
temperature-sensitive resistance element 15 whose resistance increases in response to a temperature rise
Data Source
AI summary
Provided is a brushless DC motor (2) including: a stator (5) around which windings are around; a magnet rotor (6) configured to rotate by a power supply to the stator; an inverter circuit (11) connected to the stator; a position detector (7) configured to detect a positional relationship between the magnet rotor and the windings; a speed instruction unit (13) configured to output, as a speed instruction signal, a voltage corresponding to a rotation speed of the magnet rotor; a duty determination unit (12) configured to determine a duty of a voltage applied to the stator, based on the speed instruction signal; a drive controller (14) configured to distribute and output a duty signal based on the positional relationship and the duty; and temperature-sensitive resistance elements (15) configured to, by increasing the resistance in response to a temperature rise, reduce the voltage given as the speed instruction signal.