Resolver Phase Delay Detection via Signal Differentiation
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Solution Overview
Problem
Existing methods for detecting phase delay in resolver output signals are inefficient due to increased calculation requirements and time delays caused by hardware filters, leading to inaccuracies in rotor position detection for electric vehicle motors.
Innovation Solution
An apparatus and method that differentiate the resolver output signal to obtain a differential signal, detect the peak time based on a reference voltage, and calculate the phase delay time using an excitation signal generator and controller, which includes edge time detection, noise removal, and band pass filtering to accurately determine the phase delay within a reference range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple thresholds are used to detect peak of resolver output signal, then detection accuracy is improved, but calculation amount increases and detection time increases
Solution Approach 1:
The patent extracts the essential feature for peak detection by using a single threshold comparison on the differential signal instead of multiple thresholds on the original signal. This extraction of the critical detection criterion reduces calculation complexity while maintaining detection accuracy.
Solution Approach 2:
The patent replaces the complex mechanical filtering process (hardware low pass filter and band pass filter) with a mathematical differentiation operation. This substitution eliminates the time delay inherent in hardware filters while achieving the same signal processing objective.
2Reliability
If hardware filters (low pass filter and band pass filter) are used to generate excitation signal, then signal quality is improved, but phase delay occurs between excitation signal and resolver output signal
Solution Approach 1:
The patent replaces hardware filtering mechanisms with mathematical differentiation. The differentiator circuit processes the resolver output signal directly without passing it through low pass or band pass filters, thereby eliminating the phase delay introduced by these filters while maintaining signal quality through the mathematical operation.
Solution Approach 2:
The patent changes the operational parameter from frequency-domain filtering to time-domain differentiation. By transforming the signal processing approach from filtering based on frequency characteristics to differentiation based on rate of change, the system achieves signal quality improvement without the phase delay penalty of traditional filtering methods.
3Measurement precision
If differentiation and band pass filtering are applied to resolver output signal, then phase delay detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the differentiation operation with the peak detection process into a unified approach. By detecting the peak of the differential signal directly, the system combines what would otherwise be separate processing steps into one integrated operation, reducing overall system complexity while maintaining high detection accuracy.
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 allows for high-accuracy and rapid detection of phase delay times in resolver output signals, improving motor control efficiency and accuracy despite signal distortion, and can be applied to systems controlling motor drive power.
Implementation Method 1
A single-phase exciting winding and a two-phase detection winding are wound on the stator, and a steel core shape varies with a rotation angle in the rotor such that the rotor is subject to fluctuation in magnetic flux interlinkage
Implementation Method 2
an excitation signal generator that generates an excitation signal using a square wave signal
Implementation Method 3
a controller that differentiates the signal output by the resolver to obtain a differential signal
Data Source
AI summary
An apparatus and a method for detecting a phase delay of a resolver are provided. The apparatus includes a resolver configured to output a signal corresponding to a rotation angle of a motor, an excitation signal generator configured to generate an excitation signal using a square wave signal, and a controller configured to differentiate the signal to obtain a differential signal, detect a time when the differential signal meets a reference voltage as a peak time of the signal, and detect a phase delay time of the signal based on the peak time of the signal and an edge time of the square wave signal.