Resolver Phase Compensation via Dynamic Error Correction
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Solution Overview
Problem
Existing resolver systems face challenges in accurately determining rotational positions and speeds due to phase shift errors between excitation signals and output signals, which can lead to attenuation of signal-to-noise ratio and increased vulnerability to speed and position errors.
Innovation Solution
A method is introduced that dynamically determines phase shift errors by combining digitized states of excitation and output signals, using moving averages and trigonometric manipulations to calculate a phase shift error term, allowing for recursive correction of the excitation signal to compensate for phase shifts and improve resolver-to-digital conversion accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase shift errors are not compensated, then the system structure remains simple, but the measurement precision of rotational position and speed deteriorates
Solution Approach 1:
The patent changes the parameter of excitation signal phase dynamically by calculating a phase shift error term through arithmetic operations on digitized signal states and applying recursive correction. This adjusts the excitation signal phase to compensate for detected phase shift errors, improving measurement precision without requiring specialized integrated circuits
Solution Approach 2:
The patent implements feedback by continuously monitoring the phase relationship between excitation and output signals, calculating phase shift errors, and recursively correcting the excitation signal phase. The system uses the output signals to generate feedback that informs subsequent excitation signal adjustments, creating a closed-loop control system that improves rotational position and speed determination accuracy
2Measurement precision
If specialized integrated circuits are used for resolver-to-digital conversion, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent replaces specialized integrated circuits (hardware solution) with a software-based signal processing algorithm that performs resolver-to-digital conversion. The system uses general-purpose processors to execute arithmetic operations on digitized signal states, calculate phase shift errors, and apply corrections, substituting dedicated hardware with flexible software processing
Solution Approach 2:
The patent makes a general-purpose processor perform multiple functions: digitizing resolver signals, calculating phase shift errors through arithmetic operations, generating corrected excitation signals, and determining rotational position and speed. This multi-functional approach eliminates the need for specialized integrated circuits while maintaining measurement precision
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 approach enhances the accuracy of rotational position and speed determination, reducing errors and improving diagnostic capabilities by effectively compensating for phase shifts in resolver systems without the need for specialized integrated circuits.
Implementation Method 1
electromagnetic coupling between the primary winding and the secondary windings varies with the rotational position of the rotor
Implementation Method 2
The primary winding may be excited with a sinusoidal signal, which induces differential output signals in the secondary windings
Implementation Method 3
the resolver is a variable reluctance resolver, in which an excitation winding is disposed in the stator, and an airgap between the rotor and the stator is modulated on the rotor, which modulates the transformation ratio
Data Source
AI summary
A resolver rotatably coupled to a rotatable member is described, including a method for evaluating an output signal therefrom. This includes supplying an excitation signal to the resolver and dynamically determining corresponding output signals from the resolver. A plurality of datasets are determined, with each dataset including digitized states of the excitation signal supplied to the resolver and corresponding output signals from the resolver. The digitized states of the excitation signal and the corresponding output signals from the resolver for each of the datasets are arithmetically combined, and a moving average thereof is determined. A phase shift error term is determined based upon the moving average, and a phase shift is determined between the excitation signal and the corresponding output signals based upon the phase shift error term.