No-null-shift magnetic modulation current sensor
A current sensor and magnetic modulation technology, applied in the field of electrical measurement, can solve the problems that cannot be solved fundamentally, the performance of the measurement system is degraded, etc., and achieve the effect of high-precision current non-contact measurement, high stability, and high precision
Pending Publication Date: 2015-10-14
FONRICH NEW ENERGY TECH LTD
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Problems solved by technology
Although this compensation method has certain effects, it cannot fundamentally solve the problem.
The problem of zero drift directly leads to the performance degradation of the entire measurement system
Method used
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[0012] The measured current passes through the middle of the magnetic ring of the non-zero-drift magnetic modulation current sensor. There are two coils wound on the magnetic ring of the non-zero-drift magnetic modulation current sensor. Feedback coil. The output Vs of the operational amplifier U1 reflects the magnitude of the oscillating current Id flowing through the oscillating coil L1, and the excitation circuit generates an excitation signal Vd according to the output Vs of the operational amplifier U1, forming a continuous and stable oscillation on the oscillating coil L1 and capacitor C1. When the measured current changes, a magnetic field will be formed in the magnetic ring. Since the magnetic permeability of the magnetic material is not absolutely linear, the positive half cycle and negative half cycle of the current of the oscillating coil L1 are asymmetrical at this time. The feedback circuit of the subsequent stage generates a feedback current Ib according to this ...
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The invention provides a no-null-shift magnetic modulation current sensor, belongs to the field of electrical measurement, and realizes a current sensor based on the principle of magnetic modulation. The no-null-shift magnetic modulation current sensor has no null shift problem in principle and can be widely applied to high-precision noncontact current measurement, ultralow current noncontact measurement and magnetic field measurement, etc. The no-null-shift magnetic modulation current sensor is composed of an oscillation coil L1 and a feedback coil L2 which are wound on the same magnet ring, a capacitor C1, a resistor R1, an operation amplifier U1, an excitation circuit and a feedback circuit. The oscillation circuit has capacitor isolated DC component so that the oscillation circuit certainly has no DC component, the current value of tested current through the middle of the magnet ring is absolutely in absolute proportion to feedback current Id when the magnetic field in the internal part of the magnet ring is balanced, and thus the circuit is ensured to have no null shift problem in principle. The feedback circuit part is ensured not to be influenced by analog device parameter characteristic drift especially when the feedback circuit is realized by adopting an MCU digital algorithm so that stability of higher precision is realized.
Description
technical field [0001] The invention belongs to the field of electrical measurement, and realizes a current sensor based on the principle of magnetic modulation. The principle is that there is no zero drift problem, and it can be widely used in high-precision non-contact current measurement, ultra-small current non-contact measurement, and magnetic field measurement. Wait. . Background technique [0002] Non-contact measurement with high precision and ultra-low current has applications in many industries. The mainstream technology is the principle of magnetic modulation. Although there are many circuits of magnetic modulation current sensors, most of them have the problem of zero drift, that is, when there is no current input, the measurement results of the sensor also have output drift. And often the zero drift is not fixed and will change with temperature. For the zero offset temperature, most of the current solutions are supplemented by resistors or diodes with negativ...
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Inventor 不公告发明人
Owner FONRICH NEW ENERGY TECH LTD