Magnetic Sensor Interference Suppression via Signal Processing
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Solution Overview
Problem
Existing magnetic sensor systems face challenges in reliably detecting the angular position of an excitation magnet due to interference fields, especially in environments with multiple electrical and electronic components, such as in the automobile industry.
Innovation Solution
A method and apparatus that utilize multiple magnetic field sensors arranged on an integrated circuit to generate and detect a magnetic field, with signal processing techniques including gain correction, transformation, and phase correction to accurately determine the angular position of the excitation magnet even in the presence of interference fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple magnetic field sensors are used to detect angular position in environments with interference fields, then measurement reliability is improved, but device complexity increases due to the need for multiple sensors and complex signal processing
Solution Approach 1:
The patent divides the magnetic field detection task into multiple independent sensor measurements. By using n≥2 magnetic field sensors arranged on the circuit main surface, each sensor provides an independent measurement that can be processed separately through gain correction and transformation equations, ultimately combining to produce a reliable angular position detection that overcomes individual sensor vulnerabilities to interference fields
Solution Approach 2:
The patent implements feedback through iterative signal processing steps. The detection signals undergo gain correction, transformation, and further gain correction in a sequential manner where each processing stage uses the results from previous stages. This feedback-based processing chain allows the system to compensate for interference effects and achieve reliable angular position detection despite the complexity of multiple processing operations
2Measurement precision
If signal processing processors are used to compensate for magnetic interference fields, then measurement accuracy is improved, but the complexity of compensation increases when dealing with field gradients from multiple interference sources
Solution Approach 1:
The patent applies parameter changes through gain correction factors that are calculated and applied to transform the detection signals. The gain correction parameters (kg_i, kg_out_1, kg_out2) are specifically designed to compensate for the effects of interference fields and field gradients. By changing the gain parameters of the detection signals through mathematical transformation, the system achieves accurate angular position detection without requiring complex physical compensation mechanisms for each interference source
3Object-affected harmful factors
If multiple sensors are arranged on the circuit main surface, then interference field suppression is improved, but manufacturing complexity increases
Solution Approach 1:
The patent achieves interference field suppression through universal signal processing equations that can be applied regardless of the specific interference environment. The same gain correction and transformation equations (applicable to both homogeneous and inhomogeneous fields) are used to process signals from all n sensors arranged on the circuit main surface. This universal approach allows the system to suppress interference fields effectively without requiring complex sensor-specific calibration or positioning, thereby reducing manufacturing complexity despite using multiple sensors
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
The solution enables reliable detection of the angular position of the excitation magnet, effectively suppressing interference fields and improving measurement accuracy in complex environments.
Implementation Method 1
detecting a magnetic flux density of the generated magnetic field by means of a number n≥2 of magnetic field sensors arranged on a circuit main surface of an integrated circuit
Data Source
AI summary
A method for processing detection signals of magnetic field sensors, the method comprising generating a magnetic field by an excitation magnet; detecting a magnetic flux density B1, . . . , Bn of the generated magnetic field by means of a number n≥2 of magnetic field sensors S1, . . . , Sn arranged on a circuit main surface of an integrated circuit; outputting detection signals VS1, . . . , VSn proportional to the magnetic flux density B1, . . . , Bn detected by the n magnetic field sensors S1, . . . , Sn to the integrated circuit; gain correcting the output detection signals VS1, . . . , VSn; transforming the phase-corrected detection signals VS1′, . . . , VSn′ and gain correcting the transformed detection signals Vt1, Vt2.