Coil-Based Rotor Position Detection in Compact Electric Machines
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Solution Overview
Problem
Existing rotating electrical machines with permanent magnet rotors require larger sizes to detect rotation angle positions due to the need for separate rotation position detection devices, which increases overall machine size.
Innovation Solution
The design incorporates a stator and rotor with first and second coils disposed in a manner that opposes each other along the rotation axis, allowing for voltage induction and accurate detection of the rotor's position without increasing machine size, and includes a temperature sensor and capacitive component for enhanced temperature monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate rotation position detection device is added to detect the rotation angle position of the rotor, then the detection capability is improved, but the overall machine size increases
Solution Approach 1:
The patent combines the rotation position detection function with the existing stator and rotor coils. The stator coils serve dual purposes: generating magnetic fields for motor operation and detecting rotation angle positions through induced voltages. This merging eliminates the need for separate detection devices, thereby improving measurement precision without increasing machine size.
Solution Approach 2:
The stator coils are designed to perform multiple functions: they generate the magnetic field necessary for motor operation and simultaneously serve as sensors for detecting the rotor's rotation angle position. By making the coils universal components that fulfill both actuation and sensing roles, the patent achieves position detection capability without adding extra devices that would increase the machine's volume.
2Measurement precision
If coils are disposed to closely oppose each other between stator and rotor, then detection accuracy is improved, but the structural complexity increases
Solution Approach 1:
The patent divides the detection function into multiple discrete coil pairs arranged at different angular positions around the rotor. Each coil pair independently contributes to the detection accuracy, and their segmented arrangement allows for modular design and simplified manufacturing, offsetting the potential complexity increase from the close opposition requirement.
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 enables precise detection of the rotor's rotation angle position and temperature monitoring without enlarging the machine, improving detection accuracy and maintaining compactness.
Implementation Method 1
The one or more first coils are arranged to induce a voltage in response to a relative position with respect to the one or more second coils
Implementation Method 2
a temperature sensor arranged such that an electrical resistance of the temperature sensor changes in response to a temperature of the permanent magnet
Data Source
AI summary
A rotating electrical machine includes a stator, a rotor with a permanent magnet, a first number of one or more first coils, and a second number of one or more second coils. The second number is different from the first number. The one or more first coils are disposed on the stator. The one or more second coils are disposed on the rotor. The one or more first coils and the one or more second coils are disposed on the stator and the rotor, respectively, in such a manner as to closely oppose each other in a state where the rotor is at a predetermined rotation angle position. The one or more first coils are arranged to induce a voltage in response to a relative position with respect to the one or more second coils.