Rotor Angle Measurement Using Asymmetric Tooth Wheel
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Solution Overview
Problem
Existing systems lack effective methods to accurately monitor the angular position of a rotor in electrical generators and calculate the power angle, which is crucial for maintaining stability and control in electrical power systems.
Innovation Solution
The system uses a reference signal, often derived from a time source, to determine the power angle by comparing it with a rotational position signal from a tooth wheel or terminal voltage, employing a magnetic pickup unit to induce a voltage as teeth pass a pole piece, allowing for precise calculation of the rotor's position and power angle, even with uniform teeth on the tooth wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic pickup unit is used to detect rotor position by inducing voltage as teeth pass a pole piece, then rotor angle measurement capability is provided, but the system cannot distinguish angular position when teeth are uniform
Solution Approach 1:
The patent introduces non-uniformity in the tooth wheel by providing at least one missing tooth or varying tooth spacing. This asymmetry creates a unique magnetic signature for different angular positions, allowing the magnetic pickup unit to distinguish between different rotor angles. The non-uniform tooth configuration transforms the previously indistinguishable uniform signal into a position-resolved signal pattern.
Solution Approach 2:
The patent introduces a reference signal as an intermediary element that serves as a baseline for comparison. By comparing the magnetic pickup unit output signal with this reference signal (which represents a known angular position), the system can determine the actual rotor angle through signal processing and phase comparison, even when the tooth wheel has uniform features.
2Reliability
If existing systems are used for rotor angle measurement, then system simplicity is maintained, but accurate power angle calculation and stability control are not achieved
Solution Approach 1:
The magnetic pickup unit serves multiple functions: it detects both the presence and angular position of rotor teeth, provides rotational speed information through frequency measurement, and enables power angle calculation when combined with the reference signal. This multi-functionality reduces the need for separate sensors and systems, achieving reliable power system stability control without proportionally increasing device complexity.
Solution Approach 2:
The system implements feedback by continuously comparing the magnetic pickup unit output signal with the reference signal and using this comparison to calculate the power angle in real-time. This feedback mechanism enables dynamic stability monitoring and control, allowing the system to respond to changing operating conditions and maintain reliable power system operation.
3Ease of manufacture
If uniform teeth are used on the tooth wheel, then manufacturing is simplified, but the ability to determine angular position is lost
Solution Approach 1:
Instead of manufacturing all teeth with identical precision, the patent intentionally introduces asymmetry by providing at least one missing tooth or varying the spacing between teeth. This approach actually simplifies manufacturing compared to requiring precise uniform spacing across all teeth, while simultaneously enabling angular position detection through the created non-uniform magnetic signature.
Solution Approach 2:
The patent changes the geometric parameters of the tooth wheel from uniform spacing to non-uniform spacing or missing teeth. This parameter modification transforms the tooth wheel from a simple rotational feature into a position-encoding structure, enabling angular position detection while maintaining manufacturing feasibility through controlled variations rather than precise uniformity.
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 method enables accurate determination of the power angle, facilitating stable operation and control of electrical generators by monitoring shifts in the power angle, preventing instability and allowing for informed decisions on power generation and distribution.
Implementation Method 1
employing a magnetic pickup unit to induce a voltage as teeth pass a pole piece
Data Source
AI summary
Disclosed herein are systems and methods for rotor angle measurement in an electrical generator. According to one embodiment, an intelligent electronic device may comprise control logic configured to generate a reference signal and to generate a rotational position signal based upon an indicator of a rotational position of a rotor in an electrical generator. The control logic may further be configured to detect a relative shift between the reference signal and the rotational position signal and to determine the rotational position of the rotor based upon the relative shift. A power angle of the electrical generator may be calculated based upon the rotational position of the rotor. According to certain embodiments, the control logic may further be configured to generate a control instruction to reduce the power angle in response to determining that the power angle exceeds a threshold.