AC Sensor Signal Conversion for Sub-Cycle Amplitude Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic measurement circuits for determining the voltage and phase shift of AC signals in resolvers, LVDTs, and proximity sensors require a full cycle or more of the sinusoidal waveform, leading to slow response times that are inadequate for rapidly changing parameters.
Innovation Solution
A high-speed electronic measurement circuit that uses two samples of a sinusoidal waveform spaced π/2 radians apart to determine the amplitude and phase shift, allowing for rapid calculation of the root-mean-square (RMS) value and phase shift in less than half a cycle using trigonometric substitutions and four-quadrant arctangent functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional algorithms requiring a full cycle or more of the sinusoidal waveform are used, then measurement precision is maintained, but response time deteriorates
Solution Approach 1:
The patent applies partial action by using only a portion of the sinusoidal waveform (less than a full cycle) to perform amplitude and phase measurements. Specifically, the system calculates measurements using fewer than complete waveform cycles, thereby reducing the time required while still obtaining accurate results through mathematical processing of the partial waveform data.
2Measurement precision
If more than a full cycle is used to calculate phase shift with zero crossing detection, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The patent replaces the traditional mechanical zero-crossing detection method with a mathematical computation approach. Instead of detecting zero crossings physically or through traditional circuitry over multiple cycles, the system uses mathematical algorithms to calculate phase shift from sampled waveform data, significantly reducing measurement time while maintaining precision.
Solution Approach 2:
The patent changes the measurement parameter from time-based zero-crossing detection to amplitude-based mathematical calculation. By using the relationship between voltage amplitude and phase angle in the sinusoidal waveform, the system can determine phase shift without waiting for complete cycles or detecting zero crossings, thereby improving both speed and productivity.
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
Enables quick measurement of AC voltage and phase shift, improving response times and enabling detection of changes or failures in sensors within a shorter timeframe compared to traditional methods.
Implementation Method 1
a sinusoidal waveform is typically applied to a primary coil, thereby inducing a secondary voltage in the one or more secondary coils through mutual inductive coupling between the primary and the secondary windings
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A system for determining an amplitude of a sinusoidal output waveform from a sensor includes a controller (104) configured to provide a sample signal having a sample frequency that is four times a frequency of a sinusoidal excitation waveform provided to the sensor. The sensor has inductively-coupled primary (126) and secondary (128) windings that produce the sinusoidal output waveform from the secondary winding when the excitation waveform is provided to the primary winding. An analog-to-digital converter (114) measures a first and second voltage of the sensor waveform separated in time by the period of the sample frequency, and the system calculates the amplitude based on the measurements of the first and second voltages.