Dual Secondary Winding Current Sensor for High Peak-to-Rated Ratio
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Solution Overview
Problem
Conventional compensation current sensors have a limited peak-to-rated current ratio, which restricts their ability to handle high peak currents efficiently, leading to power loss and requiring a higher turn ratio for improved performance.
Innovation Solution
A current sensor arrangement with two secondary windings and evaluation circuits that adjust compensating currents to zero the magnetic field, allowing for a higher peak-to-rated current ratio and minimizing power loss by using a magnetic core with multiple windings and a magnetic field sensor to manage the magnetic flux effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional single secondary winding is used, then the device complexity is low, but the peak-to-rated current ratio is limited to less than two
Solution Approach 1:
The single secondary winding is segmented into two separate secondary windings with different turn ratios. The first secondary winding has a turn ratio optimized for rated current measurement, while the second secondary winding has a turn ratio optimized for peak current measurement. This segmentation allows the sensor to handle both continuous and peak currents effectively, achieving a peak-to-rated current ratio greater than two without significantly increasing device complexity.
2Adaptability or versatility
If the turn ratio is increased to handle peak currents, then the peak-to-rated current ratio improves, but power loss increases
Solution Approach 1:
Different parts of the measurement system are assigned different local qualities through the two secondary windings. The first secondary winding is optimized for accurate measurement of rated current with minimal power loss, while the second secondary winding is optimized for capturing peak currents. Each winding operates in its optimal range, preventing the power loss that would occur if a single high turn-ratio winding were used for all conditions.
Solution Approach 2:
The system dynamically switches between or combines measurements from the two secondary windings based on the current conditions. During normal operation, the first secondary winding provides accurate measurements with low power loss. During peak current events, the second secondary winding becomes active. This dynamic adaptation allows the system to maintain low power loss while achieving high peak-to-rated current ratio capability.
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 a higher peak-to-rated current ratio, reducing power loss and improving the sensor's ability to handle high peak currents, while maintaining minimal power consumption.
Implementation Method 1
The current to be measured flows through the primary conductor and generates a (primary) magnetic field in the magnetic core
Implementation Method 2
the magnetic flux in the magnetic core is measured by means of a magnetic field sensor and adjusted to zero using an evaluation circuit, whereby a suitable compensation current is fed into the compensation winding
Data Source
AI summary
The current sensor arrangement according to the compensation principle has a primary conductor, designed to generate a primary magnetic field dependent on a current to be measured flowing through it, a first secondary winding, designed to generate a first secondary magnetic field dependent on a first compensation current flowing through said winding, a second secondary winding designed to generate a second secondary magnetic field dependent on a second compensation current flowing through said winding, a magnetic field sensor designed to generate a measurement signal that represents a magnetic field detected by it; a magnetic core of soft magnetic material designed and arranged to magnetically interconnect a primary conductor, a first seconding winding, a second secondary winding, and a magnetic field sensor; a first evaluation circuit, downstream from the magnetic field sensor and upstream from the first secondary winding, and a second evaluation circuit, upstream from the second secondary winding.