Resolver Sine Cosine Coil Sinusoidal Overlap Waveform Smoothing
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Solution Overview
Problem
Conventional resolvers with two-phase detection coils adjacent to each other face challenges in maintaining a smooth signal waveform due to sudden changes in induced voltage magnitude, which is difficult to adjust smoothly and complicates the structure, making it hard to reduce size and weight.
Innovation Solution
A resolver design featuring sine and cosine coils with overlapping areas that change sinusoidally as the rotor rotates, allowing continuous variation of magnetic flux and signal waveform smoothing without increasing complexity or size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-phase detection coils are disposed adjacent to each other to improve angle detection accuracy, then the distances of the two-phase detection coils to the excitation coil are substantially identical, but the magnitude of the voltage induced in each detection coil suddenly changes when the rotor is rotated, causing signal waveform distortion
Solution Approach 1:
The patent applies local quality by making the detection coils have different numbers of turns (first detection coil has more turns than second detection coil) to create different induced voltage magnitudes. This local differentiation allows the system to compensate for the sudden voltage changes during rotor rotation, smoothing the signal waveform while maintaining the geometric arrangement for accurate angle detection.
2Reliability
If the number of turns of the coil is changed to gradually change the voltage induced, then the signal waveform can be smoothed, but the structure becomes complicated and it is difficult to reduce the size and weight of the resolver
Solution Approach 1:
Instead of making all detection coils have different numbers of turns (which would complicate the structure), the patent applies local quality by differentiating only between the first and second detection coils in terms of turn count. This selective differentiation achieves signal waveform smoothing while keeping the overall coil structure simple and maintainable.
3Reliability
If the number of turns of the coil is changed to adjust the voltage induced, then the signal waveform can be smoothed, but the size and weight of the resolver increase
Solution Approach 1:
The patent minimizes weight increase by differentiating the number of turns only between the first and second detection coils rather than uniformly increasing turns across all coils. This localized approach achieves the necessary voltage adjustment for waveform smoothing while keeping the overall resolver weight increase minimal.
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 design achieves a good signal waveform with a simple configuration, improving angular resolution and reducing manufacturing complexity and costs while maintaining efficient signal transmission.
Implementation Method 1
a resolver that detects a rotation angle of a rotor with respect to a stator, wherein the resolver includes a sine coil and a cosine coil that transmit AC signals having phases of the electrical angle different from each other by 90 degrees
Data Source
AI summary
A resolver includes a sine coil and a cosine coil that transmit AC signals having phases of the electrical angle different from each other by 90 degrees in one of a sheet-like excitation coil and a sheet-like detection coil disposed at a rotor or a stator, and a counter coil or a conductor disposed to face the sine coil and the cosine coil in the other of the excitation coil and the detection coil. In addition, an area (S) of a portion where each of the sine coil and the cosine coil and the counter coil or the conductor overlap each other when viewed in the axial direction of the resolver changes into a sinusoidal shape as the rotor rotates.