Resolver Position Error Compensation via Angular Velocity Conversion
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Solution Overview
Problem
The position error of a resolver varies with velocity due to the characteristic of the angle tracking observer (ATO), making it challenging to compensate for position information errors across different velocities in digital converter chips or software implementations.
Innovation Solution
An apparatus and method that include a resolver-digital converter and a position error compensation learner to estimate position information, determine and convert position error components to a standard electric angular velocity, allowing for accurate compensation by reflecting these errors in the resolver-digital converter, using a mapping table or frequency response characteristics of the ATO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position error compensation methods are used at constant velocity, then compensation is simple and straightforward, but the position error varies with velocity due to ATO characteristics making the compensation ineffective at different velocities
Solution Approach 1:
The patent transforms the position error component from its original velocity-dependent form into a velocity-independent form by changing the reference frame parameters. Specifically, it converts the position error measured at operating velocity into equivalent position error components at zero velocity using the ATO frequency response characteristics, allowing the compensation to be universally applicable across all velocities.
2Ease of manufacture
If the position error is measured at a particular velocity, then the measurement is straightforward, but the measured error cannot be used for compensation at other velocities
Solution Approach 1:
The patent introduces the ATO frequency response characteristic as an intermediary that bridges the gap between position error measurements at different velocities. By using the ATO's known frequency response characteristics as a transfer function, the system can convert position error components from one velocity reference to another, enabling universal compensation.
3Measurement precision
If velocity-dependent position error compensation is implemented for each velocity, then accurate compensation at each velocity is achieved, but the system complexity increases significantly
Solution Approach 1:
The patent creates a universal compensation approach where a single compensation mechanism can handle all velocities. By transforming the position error into the zero-velocity reference frame using ATO frequency response characteristics, the system achieves velocity-independent compensation, eliminating the need for separate compensation mechanisms for each velocity and significantly reducing system complexity.
Data Source
AI summary
An apparatus for compensating for a position information error of a resolver includes: a resolver-digital converter configured to generate a corresponding output angle by estimating resolver position information from a resolver output signal; and a position error compensation learner configured to determine a position error component in a corresponding electric angular velocity of the resolver output signal using the resolver output signal and the output angle and to convert the position error component to a position error component in an electric angular velocity 0. The resolver-digital converter compensates for an error by reflecting the position error component in the electric angular velocity 0 in the error between a position angle of the resolver output signal and the output angle.