Brush Angular Interval Optimization for DC Motor Ripple Reduction
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Solution Overview
Problem
Six pole and thirteen slot motors experience increased current ripple and torque due to the increased number of short-circuited coils, leading to inefficiencies in current supply and torque generation.
Innovation Solution
The motor design features brushes positioned at an angular interval of 63° to 66° around the rotary shaft, with a stator having six poles and a rotor with thirteen slots, and includes three divided cores with magnets, optimizing the contact area between brushes and commutator to minimize current ripple and maximize torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two brushes are disposed to have an angular interval of 60° in a six pole and thirteen slot motor, then the motor structure is simple and easy to manufacture, but the current ripple and torque ripple are increased
Solution Approach 1:
The patent changes the angular interval parameter of the brushes from the conventional 60° to a specific range of 63° to 66°. This parameter modification optimizes the current distribution in the thirteen slots, reducing the number of short-circuited coils and thereby minimizing current ripple and torque ripple while maintaining manufacturing feasibility
2Ease of operation
If the number of short-circuited coils is increased in a six pole and thirteen slot motor, then the motor can operate with conventional brush positioning, but the current ripple and torque ripple are increased
Solution Approach 1:
By modifying the brush angular interval to 63°-66°, the patent changes the operational characteristics of the motor. This parameter change reduces the number of short-circuited coils during operation, thereby reducing current ripple and torque ripple while maintaining compatible operation with the six pole and thirteen slot configuration
3Object-generated harmful factors
If brushes are positioned at an angular interval of 63° to 66°, then current ripple is minimized and torque is maximized, but the brush positioning precision requirement is increased
Solution Approach 1:
The patent specifies a range (63° to 66°) rather than a single precise angle, which optimizes performance by reducing current and torque ripple. The range provides a manufacturing tolerance window that balances performance optimization with practical manufacturing capabilities, reducing the stringency of precision requirements compared to a single-angle specification
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
This configuration minimizes current ripple and maximizes torque by optimizing the angular positioning and width of brushes and commutator pieces, enhancing the motor's efficiency and performance.
Implementation Method 1
brushes are in contact with the commutator to supply a current to the commutator
Implementation Method 2
Rotation of the rotor is induced due to an electrical interaction in the motor
Data Source
AI summary
The present invention provides a stator including magnets having six poles; a rotor disposed inside the stator and including thirteen slots; a coil wound around the slot; a rotary shaft coupled to the rotor; a commutator coupled to the rotary shaft and connected to the coil; and a plurality of brushes disposed to be pressed against the commutator and located to have an angular interval of 63° to 66° in the circumferential direction of the rotary shaft, thereby providing advantageous effects in that a current ripple is minimized and a torque is maximized.