Inductive Sensor Angular Position Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the angular position of a rotating object using inductive sensors, such as resolvers or variable-reluctance sensors, face challenges when the signal amplitude becomes very small near zero crossing, limiting flexibility in sampling time and leading to lag errors with changing angular velocities.
Innovation Solution
An assembly with an inductive sensor and phase shifters that generates additional signals from the excitation and secondary windings, allowing for evaluation at any time using an evaluation circuit with polarity sign determination units, enabling the calculation of the current angular position without the mentioned disadvantages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sampling is performed at fixed phase relationship to excitation voltage to ensure sufficient signal amplitude, then measurement reliability is improved, but flexibility in sampling time is lost
Solution Approach 1:
The system dynamically selects between different signal pairs based on the current excitation phase. The evaluation unit determines which secondary winding signals provide sufficient amplitude at the current sampling moment, allowing the sampling time to be freely chosen while maintaining measurement reliability through adaptive signal selection.
Solution Approach 2:
The system changes the effective signal parameters by selecting different combinations of secondary windings and their complementary signals based on the excitation phase. This allows the same physical hardware to provide reliable measurements across all phases without fixed sampling constraints.
2Ease of operation
If phase-locked loops are used to calculate angle from predetermined values, then ease of operation is improved, but lag errors occur with changing angular velocities
Solution Approach 1:
Instead of using PLL to track the excitation signal and derive angle, the system inverts the approach by directly evaluating the instantaneous relationship between secondary winding signals and the current excitation phase. This eliminates the synchronization lag inherent in PLL while maintaining ease of operation through direct calculation.
Solution Approach 2:
The system performs preliminary phase detection of the excitation signal and uses this information to select the appropriate signal pair before angle calculation. This preliminary action ensures that the correct signals are always used without requiring continuous PLL synchronization, eliminating lag errors while maintaining operational simplicity.
3Device complexity
If direct evaluation of Us(t) and Uc(t) is performed, then device complexity is reduced, but measurement precision deteriorates near zero crossing
Solution Approach 1:
The evaluation unit dynamically adapts its calculation approach based on the excitation phase. Near zero crossings, it automatically selects signal pairs with sufficient amplitude, while at other phases it uses the standard evaluation method. This dynamic adaptation maintains measurement precision across all angles without significantly increasing device complexity.
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 the determination of the angular position at any time without lag errors or phase-related limitations, ensuring a stable signal for accurate angle calculation.
Implementation Method 1
an inductive sensor with at least one primary winding being fed an excitation signal and at least two secondary windings inductively coupled thereto. The inductive coupling causes signals to be generated with a periodic and phase-shifted waveform in the two secondary windings
Data Source
AI summary
An assembly and a method determine the angular position of a rotating machine by way of an inductive sensor. From the excitation signal for a primary winding of a sensor and voltages induced in the two secondary windings of the sensor, three more signals are derived using phase shifters and polarity sign determination units. The six signals in total are sampled using a sample and hold sampling unit and provided to a processor for evaluation, which then calculates the current angular position of the rotating machine at the sampling time.