Magnetoelectric Sensor Frequency Conversion via Electrical Modulation
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Solution Overview
Problem
Magnetoelectric sensors (ME sensors) face challenges in measuring low-frequency magnetic fields due to significant deterioration in detection limits and interference from bias magnetic fields, especially when multiple sensors are in close proximity, requiring complex and energy-intensive modulation magnetic fields for frequency conversion.
Innovation Solution
A magnetic field measurement method using a magnetoelectric composite element with a dielectric phase exhibiting non-linear strain-voltage characteristics, where a time-periodic electrical modulation voltage is applied to achieve frequency conversion without a modulation magnetic field, allowing for improved sensitivity and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a static bias magnetic field is applied to operate the ME sensor at the favorable operating point, then the linearity and signal-to-noise ratio of the voltage response are improved, but mutual interference between multiple sensors occurs and additional magnetic field generation equipment is required
Solution Approach 1:
The patent replaces the magnetic field-based biasing system with an electrical field-based system. Instead of using permanent magnets or current conductors to apply a static bias magnetic field, the invention applies a time-periodic electrical modulation voltage to the piezoelectric phase, which mechanically couples to the magnetostrictive phase to achieve the same operating point optimization without requiring external magnetic field generation equipment.
Solution Approach 2:
The patent introduces the piezoelectric phase as an intermediary between the electrical modulation voltage and the magnetostrictive phase. The electrical modulation voltage acts on the piezoelectric phase, which through mechanical coupling transfers the effect to the magnetostrictive phase, thereby indirectly achieving the desired biasing effect without direct magnetic field application.
2Measurement precision
If a modulation magnetic field is used for frequency conversion to measure low-frequency magnetic fields, then the detection limit is improved, but energy consumption increases and device complexity increases
Solution Approach 1:
The patent replaces the energy-intensive modulation magnetic field system with an electrical modulation voltage system. Instead of using current conductors to generate a time-periodic modulation magnetic field, the invention applies an electrical modulation voltage directly to the piezoelectric phase, which through mechanical coupling achieves frequency conversion with significantly lower energy consumption.
Solution Approach 2:
The patent changes the physical parameter used for modulation from magnetic field strength to electrical voltage. By applying a time-periodic electrical modulation voltage with a frequency different from the natural frequency of the oscillator, the system achieves frequency conversion and improved detection limits without the energy penalties associated with magnetic field generation.
3Area of stationary object
If multiple ME sensors are placed in close proximity, then measurement coverage is improved, but mutual interference from bias magnetic fields increases
Solution Approach 1:
The patent eliminates the source of mutual interference by replacing the magnetic field-based biasing system with an electrical field-based system. Since electrical modulation voltages applied to individual sensors do not generate interfering magnetic fields in adjacent sensors, multiple sensors can be placed in close proximity without mutual interference, thereby improving measurement coverage.
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
This approach enhances the detection limits of ME sensors for low-frequency magnetic fields by resonance amplification and reduces the need for bias magnetic fields and energy-intensive modulation, providing a simpler and more efficient apparatus for magnetic field measurement.
Implementation Method 1
Under the influence of a magnetic field, it undergoes a change in length, shape or volume.
Implementation Method 2
The piezoelectric phase, e.g. made of lead zirconate titanate (PZT), polyvinylidene fluoride (PVDF), aluminum nitride (AIN), also experiences a change in length due to the material connection with the magnetostrictive phase in the ME composite due to a magnetic field and generates a measurable change the electrical polarization, which can be detected as an electrical voltage or charge change
Implementation Method 3
providing at least one dielectric phase in material connection with the magnetostrictive phase of the composite element, wherein the dielectric phase shows a change in length when an electrical voltage is applied, the magnitude of which is non-linearly dependent on the magnitude of the voltage
Implementation Method 4
ME sensors are basically designed as mechanical oscillators and have a mechanical natural frequency that can be easily determined.
Implementation Method 5
applying a time-periodic electrical modulation voltage to achieve frequency conversion without a modulation magnetic field
Data Source
Figure 1
Figure 2A~2C
AI summary
The invention relates to a magnetic field measurement method with a magnetoelectric composite element as an oscillator, in which a time-dependent measuring magnetic field acts on the magnetostrictive phase of the composite element, an electrical measuring voltage is tapped across the piezoelectric phase of the composite element, and the measuring magnetic field is inferred from this, characterized by the steps of providing at least one dielectric phase in a material-bonded connection with the magnetostrictive phase of the composite element, wherein the dielectric phase exhibits a change in length when an electrical voltage is applied, the magnitude of which depends non-linearly on the magnitude of the voltage, and applying a time-periodic electrical modulation voltage to the dielectric phase. The invention further relates to magnetic field measuring devices.