Radiation-Hardened Current Sensor Using DCCT and ACCT Filtering
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Solution Overview
Problem
Conventional current sensors are impractical for space applications due to radiation exposure, as they rely on sensitive components that are difficult and expensive to make radiation-hardened.
Innovation Solution
A radiation-hardened current sensor with an active filter, comprising a DC current transformer and an AC current transformer, along with a self-oscillating modulator and active filter, maintains magnetic flux density within limits and separates DC, low frequency AC, and high frequency AC components, using a comparator to control switches for magnetic flux regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current sensor components are used, then the sensor can operate in terrestrial environments, but the sensor becomes impractical in space applications due to radiation exposure
Solution Approach 1:
The current sensor is divided into separate functional modules: a first current transformer for DC and low-frequency AC sensing, an active filter for frequency separation, and a second current transformer for high-frequency AC sensing. Each module can be independently designed and manufactured with appropriate radiation hardening techniques, avoiding the need to manufacture an entirely complex sensor as a single unit.
Solution Approach 2:
An active filter is introduced as an intermediary component between the two current transformers. This filter separates the frequency components and conditions the signals, enabling each transformer to operate in its optimal frequency range while being protected from radiation-induced interference by the filtering action.
2Measurement precision
If a single current transformer is used to sense all frequency components, then the device complexity is reduced, but the measurement precision across wide frequency ranges deteriorates
Solution Approach 1:
The frequency sensing range is segmented into two distinct bands: DC and low-frequency AC handled by the first current transformer, and high-frequency AC handled by the second current transformer. This segmentation allows each transformer to be optimized for its specific frequency range, achieving high measurement precision across the entire spectrum while maintaining manageable device complexity through functional division.
Solution Approach 2:
Each current transformer is designed to handle only the frequency components it is optimized for, rather than attempting to handle all frequencies. The first transformer focuses on DC and low-frequency AC, while the second focuses on high-frequency AC, with the active filter managing the transition and separation between these partial actions to achieve complete frequency coverage.
3Reliability
If radiation-hardened components are manufactured, then the sensor becomes suitable for space applications, but the manufacturing cost and complexity increase significantly
Solution Approach 1:
The sensor is segmented into modular components that can each be manufactured using standard radiation hardening techniques appropriate for their specific function. This allows manufacturers to apply proven, less complex hardening methods to individual modules rather than attempting to harden a single complex integrated sensor, reducing overall manufacturing difficulty while maintaining radiation resistance.
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 accurate current sensing across a wide frequency range from DC to several MHz in radiation-exposed environments, effectively counteracting radiation-induced effects and providing robust performance in space-based systems.
Implementation Method 1
maintains a magnetic flux density of the DCCT at an upper limit and a lower limit of a magnetic hysteresis characteristic of the DCCT
Implementation Method 2
An AC current transformer (ACCT) includes a primary ACCT winding and a secondary ACCT winding... the secondary ACCT winding provides the high frequency AC
Data Source
AI summary
A radiation hardened current sensor to sense direct current (DC), low frequency alternating current (AC), and high frequency AC includes a DC current transformer (DCCT) including a primary DCCT winding and a secondary DCCT winding. A self-oscillating modulator is coupled to the secondary DCCT winding of the DCCT to maintain a magnetic flux density of the DCCT at an upper limit and a lower limit of a magnetic hysteresis characteristic of the DCCT. An active filter passes only the DC and the low frequency AC from the DCCT as an output. An AC current transformer (ACCT) including a primary ACCT winding and a secondary ACCT winding. The output of the active filter is coupled to the ACCT and the secondary ACCT winding provides the high frequency AC.