Resolver Calibration for Offset and Group Delay in Electrical Machines
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Solution Overview
Problem
Existing methods for calibrating resolver offsets in electrical machines, particularly those using delta-sigma analog-to-digital conversion, face challenges due to mechanical resolver offsets and group delays, leading to inaccurate rotor position determination and efficiency issues.
Innovation Solution
A computer system is configured to determine resolver offset and delay errors by calculating averages of current load angles at various speed intervals, allowing for simultaneous calibration of mechanical offsets and group delays, using available current data and active short circuit modes to simplify the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If resolver mechanical offset is calibrated using PI controller with d-axis voltage set to zero, then single parameter calibration is achieved, but dual parameter calibration (offset and group delay) is not possible
Solution Approach 1:
The patent adds another dimension to the calibration process by utilizing both magnitude and phase information from current measurements across multiple rotor positions. This multi-dimensional approach enables the extraction of both resolver offset and group delay error parameters from the same measurement data, achieving dual-parameter calibration without significantly increasing process complexity
Data Source
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AI summary
A computer system (100, 500) is provided, comprising processing circuitry (502) configured to: determine (210) a first average of a measured current load angle (δm(n)) of an electrical machine (10) and a first average of a correct current load angle (δc(n)) of the electrical machine (10) for a plurality of positive speed values within a positive speed interval, determine (212) a second average of the measured current load angle (δm(n)) of the electrical machine (10) and a second average of the correct current load angle (δc(n)) of the electrical machine (10) for a plurality of negative speed values within a negative speed interval, determine (214) a resolver offset error (θoffset) of the electrical machine (10) from the first and second average of the measured current load angle (δm(n)), and determine (216) a resolver delay error (τgd) of the electrical machine (10) from the first and second average of the measured current load angle (δm(n)), from the first and second average of the correct current load angle (δc(n)), and from the rotor speed (ωe).