Extending the GMR current measurement range with a counteracting magnetic field

Area of Science:

• Electrical Engineering
• Sensor Technology
• Materials Science

Background:

• Traditional current transformers are bulky and unsuitable for power electronics.
• Semiconductor sensors like Hall and Giant Magnetoresistive (GMR) offer advantages but have limited current ranges.
• Existing GMR sensors are typically limited to unipolar measurements around 9 A.

Purpose of the Study:

• To design and implement a novel current sensor system for extending the measurement range of GMR sensors.
• To overcome the inherent limitations of semiconductor-based current sensing devices in electrical networks.
• To enable accurate current measurement in power electronic circuits using an enhanced GMR sensor.

Main Methods:

• A new design utilizing a counteracting magnetic field principle was developed.
• A prototype sensor was constructed and tested to validate the design.
• A microcontroller unit (MCU) was integrated for automatic scaling and performance optimization.

Main Results:

• The proposed design successfully extended the GMR sensor's current measurement range from 9 A (unipolar) to ±45 A.
• Experimental results demonstrated the linear operation and effectiveness of the counteracting magnetic field approach.
• The MCU-based automatic scaling function optimized the sensor's performance across the extended range.

Conclusions:

• The counteracting magnetic field design is a viable method for significantly enhancing GMR current sensor range.
• The developed sensor is suitable for accurate current measurement in low-voltage electrical networks and power electronics.
• This innovation provides a cost-effective and compact solution compared to traditional current transformers.