Current Sensor Fusion Using Shunt and Hall Probability Estimation
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Solution Overview
Problem
Conventional current detection methods using shunt resistors and Hall elements suffer from low accuracy due to noise from ambient temperature and electromagnetic interference, respectively, when used alone.
Innovation Solution
A current detection apparatus that combines shunt resistor and Hall element measurements, treating the detected values as probability distributions to synthesize a more accurate current value through maximum likelihood estimation and Bayesian updating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shunt resistor is used for current detection, then the current can be detected, but noise from ambient temperature reduces detection accuracy
Solution Approach 1:
The patent combines two different current detection methods (shunt resistor and Hall element) into a unified detection system. The shunt resistor provides accurate low-current detection while the Hall element provides accurate high-current detection, and their results are synthesized through probability distribution merging to achieve high accuracy across the entire current range, overcoming the temperature noise limitation of the shunt resistor alone.
Solution Approach 2:
The patent uses a composite detection approach by combining two different detection principles (shunt resistor and Hall element) similarly to how composite materials combine different materials properties. Each detection method has complementary strengths and weaknesses, and their combination creates a detection system with superior overall performance that overcomes the individual limitations of each method.
2Measurement precision
If a Hall element is used for current detection, then the current can be detected, but electromagnetic interference reduces detection accuracy
Solution Approach 1:
The patent merges the output signals from the Hall element and shunt resistor through probability distribution synthesis. The shunt resistor provides a reference measurement that is less susceptible to electromagnetic interference, and combining it with the Hall element output through maximum likelihood estimation filters out the interference while preserving the accurate current measurement capability of the Hall element.
3Adaptability or versatility
If both shunt resistor and Hall element are used together, then detection coverage is improved, but handling and synthesizing the two detected values increases system complexity
Solution Approach 1:
The patent transforms the raw detected current values from both sensors into probability distributions characterized by mean values and variances. This parameter transformation simplifies the synthesis process by converting complex sensor outputs into standardized statistical parameters that can be easily combined through mathematical operations like maximum likelihood estimation, reducing the overall system 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
This approach enhances current detection accuracy by compensating for the limitations of individual sensors, improving the reliability of current measurement by handling noise effectively.
Implementation Method 1
a first current detection unit configured to detect a current flowing through a conductive wire with a shunt resistor connected to the conductive wire
Implementation Method 2
a second current detection unit configured to detect the current with a Hall element
Data Source
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AI summary
A current detection apparatus includes a first current detection unit configured to detect a current flowing through a conductive wire with a shunt resistor connected to the conductive wire to obtain a first detected current value; a second current detection unit configured to detect the current with a Hall element to obtain a second detected current value; a storage unit configured to store a first probability distribution information of the first current detection unit and a second probability distribution information of the second current detection unit; a synthesis unit configured to convert the first and second detected current values into first and second probability distributions based on the first and second probability distribution information, respectively, and to synthesize the first and second probability distributions to obtain a synthesized distribution; and an estimation unit configured to obtain an estimated current value via a maximum likelihood estimation based on the synthesized distribution.