Hall-Effect Sensor Technique for No Induced Voltage in AC Magnetic Field
Measurements Without Current Spinning
Abstract
Accurately sensing AC magnetic field signatures poses a series of
challenges to commonly used Hall-effect sensors. In particular, induced
voltage and lack of high-frequency spinning methods are bottlenecks in
the measurement of AC magnetic fields. We describe a magnetic field
measurement technique that can be implemented in two ways: 1) the
current driving the Hall-effect sensor is oscillating at the same
frequency as the magnetic field, and the signal is measured at the
second harmonic of the magnetic field frequency, and 2) the frequency of
the driving current is preset, and the measured frequency is the
magnetic field frequency plus the frequency of the current. This method
has potential advantages over traditional means of measuring AC magnetic
fields used in power systems (e.g., motors, inverters), as it can reduce
the components needed (subsequently reducing the overall cost and size)
and is not frequency bandwidth limited by current spinning. The sensing
technique produces no induced voltage and results in a low offset, thus
preserving accuracy and precision in measurements. Experimentally, we
have shown offset voltage values between 8 and 27 μT at frequencies
ranging from 100 Hz to 1 kHz, validating the potential of this technique
in both cases