Current Sensor Switching Between Magnetic Proportional and Balance Detection
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Solution Overview
Problem
Current sensors face challenges in achieving high-precision measurement across a wide range while minimizing power consumption and maintaining space efficiency, particularly due to limitations in magnetic saturation and complex configurations when using magnetoresistive elements.
Innovation Solution
A current sensor design that incorporates a magnetic balance sensor with a feedback coil and switching means to toggle between magnetic proportional detection and magnetic balance detection, allowing for a single sensor to operate effectively across a wide range with reduced power consumption by using magnetic proportional detection for small currents and magnetic balance detection for larger currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a magnetic proportional current sensor using a Hall element is used in a wider measurement range, then the measurement range is extended, but the resolution for small measurement current deteriorates
Solution Approach 1:
The patent implements dynamic switching between two detection modes (magnetic proportional detection and magnetic balance detection) based on the magnitude of measurement current. The switching means automatically selects the appropriate detection mode, enabling the system to adapt its characteristics to the current range, thereby achieving both wide measurement range and high resolution for small currents
Solution Approach 2:
The patent divides the measurement range into two segments: small current range handled by magnetic proportional detection and large current range handled by magnetic balance detection. This segmentation allows each detection mode to operate in its optimal range, with the switching means coordinating between them to cover the full measurement spectrum
2Area of moving object
If a magnetic balance current sensor using a Hall element is used, then the measurement range is extended, but the ability to cancel large current magnetic fields deteriorates
Solution Approach 1:
The system dynamically switches to magnetic proportional detection mode when measurement current exceeds a predetermined threshold, preventing the magnetic balance sensor from attempting to cancel excessively large magnetic fields that would cause saturation. This dynamic adaptation maintains reliability across the full measurement range
3Adaptability or versatility
If two types of current sensors are prepared separately for switching detection, then detection versatility is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines both magnetic proportional detection and magnetic balance detection functionalities into a single integrated current sensor device. The switching means enables seamless transition between detection modes within one compact unit, eliminating the need for separate sensor preparations and reducing overall device complexity while maintaining detection versatility
Solution Approach 2:
The integrated current sensor achieves multi-functionality by incorporating both detection modes in a single device. The switching means enables the sensor to perform both magnetic proportional detection and magnetic balance detection, providing universal current measurement capability across different current ranges without requiring multiple separate sensors
4Measurement precision
If a GMR element is used as a magnetic detection device in magnetic balance detection, then measurement capability is improved, but magnetic saturation occurs at large currents
Solution Approach 1:
The system dynamically switches from magnetic balance detection to magnetic proportional detection when measurement current approaches levels that would cause GMR element saturation. This dynamic protection mechanism preserves the high measurement precision of the GMR element in its optimal range while preventing harmful saturation effects at large currents
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 design achieves compatibility between high-precision measurement in a wide range and power saving, while also ensuring space efficiency, by leveraging the characteristics of magnetoresistive elements and feedback coils to cancel induction fields, thus overcoming the limitations of existing technologies.
Implementation Method 1
a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field
Implementation Method 2
a magnetic sensor element varying in characteristics due to an induction field caused by measurement current
Data Source
AI summary
A current sensor includes a magnetic balance sensor and a switching circuit. The magnetic balance sensor includes a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to application of an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field. The switching circuit switches between magnetic proportional detection and magnetic balance detection. The magnetic proportional detection is configured to output a voltage difference as a sensor output. The magnetic balance detection is configured to output, as a sensor output, a value corresponding to current flowing through the feedback coil when a balanced state in which the induction field and the canceling magnetic field cancel each other out is reached after the feedback coil is energized by the voltage difference.