Resolver Multiplication Factor Detection for Mechanical Angle Identification
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Solution Overview
Problem
In motor control systems, especially those with multiple pole pairs, the electrical angle output by sensors like resolvers cannot accurately distinguish between mechanical angles 0°-180° and 180°-360° due to variations in machining accuracy, leading to deviations in output values when converting mechanical to electrical angles.
Innovation Solution
An angle of rotation detection device that uses a two-phase encoder output to extend the bit count of a counter, allowing identification of the mechanical angle by accounting for the multiplication factor of the resolver, thereby correcting property deviations without modifying the conventional control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resolver with multiplication factor is used to detect electrical angle in motors with multiple pole pairs, then the electrical angle measurement range is extended, but the ability to distinguish mechanical angle positions deteriorates
Solution Approach 1:
The patent divides the electrical angle measurement into multiple segments by introducing a multiplication factor detector that identifies which mechanical angle segment (0°-180° or 180°-360°) the current electrical angle belongs to. This segmentation allows the system to maintain extended measurement range while recovering mechanical angle position information through counter value analysis.
Solution Approach 2:
The patent adds a new dimension to the measurement system by extending the counter bits to track mechanical angle segments. Instead of relying solely on electrical angle values, the system uses extended counter values that incorporate mechanical angle segment information, effectively adding a dimensional layer to distinguish between different mechanical angle positions.
2Measurement precision
If the counter bits are extended to detect mechanical angle, then the mechanical angle position identification is improved, but the device complexity increases
Solution Approach 1:
The patent makes the existing counter serve multiple functions by extending its bits. The extended counter not only counts electrical angle cycles but also identifies mechanical angle segments. This multi-functionality approach improves mechanical angle detection without adding separate dedicated hardware components, thereby limiting the increase in device complexity.
Solution Approach 2:
The multiplication factor detector acts as an intermediary component that processes the relationship between electrical angle and mechanical angle. It analyzes counter value changes and determines which mechanical angle segment is active, serving as a mediator between the resolver output and the control system without requiring direct modification of the resolver or encoder hardware.
Data Source
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AI summary
An angle of rotation detection device includes an electrical angle detector (resolver (12) and R/D converter (14)) having the electrical angle of 360° set smaller than the mechanical angle of 360°, and providing a two-phase encoder signal corresponding to the electrical angle of a rotor; a two-phase encoder counter (41) counting a two-phase encoder signal, and providing a digital value corresponding to the electrical angle, and a multiplication factor detector (42) detecting which position of the mechanical angle the electrical angle indicated by the signal output from the detector corresponds to, based on a change of the count value from the two-phase encoder counter. Thus, there can be provided an angle of rotation detection device that can identify the position of the mechanical angle while using the two-phase encoder output.