Airborne TEM Reception Compensation Using Magnetic Core Flux Control
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Solution Overview
Problem
Existing airborne transient electromagnetic methods face challenges in achieving ideal compensation of the primary field interference, leading to undercompensation or overcompensation of the receiver coil, which weakens the secondary field signal and reduces exploration effectiveness.
Innovation Solution
A reception compensation apparatus is designed with a transmitter coil, receiver coil, compensation coil, and compensation magnetic core, where the compensation coil is disposed around the transmitter coil and neutralized using an addition/subtraction circuit, and a shielded twisted pair is used to connect the coils, ensuring thorough suppression of the primary field without affecting the secondary field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a transmission compensation coil is placed at 1/3 of the radius of the transmitter coil to suppress primary field interference, then the induction signal of the primary field is greatly suppressed, but the position adjustment is difficult and the compensation is either under or over, failing to achieve ideal measurement signal
Solution Approach 1:
The patent introduces a compensation magnetic core as an intermediary component between the transmitter coil and compensation coil. This magnetic core concentrates and guides the magnetic flux, enabling more precise and controllable compensation of the primary field interference. The magnetic core acts as a mediator that enhances the interaction between the coils while providing a stable reference for compensation, thereby achieving ideal measurement signal without under or over compensation.
Solution Approach 2:
The patent changes the physical and magnetic parameters of the compensation system by introducing a magnetic core with specific permeability properties. This allows for adjustable and optimized compensation effects by modifying the magnetic circuit characteristics. The magnetic core enables fine-tuning of the compensation coil's effectiveness, ensuring precise cancellation of primary field interference while maintaining measurement accuracy.
2Object-affected harmful factors
If a transmission compensation coil is used to suppress primary field induction signal, then the primary field interference is reduced, but the energy injected into the earth by the primary field is weakened, reducing the secondary field strength and exploration effect
Solution Approach 1:
The patent extracts and separates the compensation function from the energy injection function. The compensation magnetic core and compensation coil are designed to specifically target and cancel only the harmful primary field interference at the receiver location, while the main transmitter coil continues to inject full energy into the earth. This separation allows independent optimization of both interference suppression and energy injection, preventing the weakening of secondary field strength.
3Ease of manufacture
If the transmitter coil uses a polygon to approximate a circle, then the manufacturing is simplified, but it is difficult to adjust the compensation coil to an ideal position, resulting in under or over compensation
Solution Approach 1:
The magnetic core serves as a stable geometric reference and magnetic flux concentrator that simplifies positioning. By providing a well-defined magnetic circuit path and physical structure, the magnetic core makes it easier to position the compensation coil at the correct location relative to the polygonal transmitter coil, thereby achieving ideal compensation without requiring complex positioning adjustments.
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 apparatus provides flexible and efficient compensation, allowing for cleaner secondary field signals, enhancing exploration depth and resolution by completely suppressing the primary field without impacting the energy injected into the earth.
Implementation Method 1
the transmitter coil has relatively large inductance and a transmission current up to hundreds of amperes. When transmission is disabled, however, the transmission current cannot immediately fall to zero, but with a relatively long current falling time. In this process, a very large induction voltage without geological information is generated on the receiver coil
Implementation Method 2
at least one compensation magnetic core, where the transmitter coil is disposed around the periphery of the receiver coil, the at least one compensation magnetic core is disposed around an outer surface of transmitter coil
Data Source
AI summary
A reception compensation apparatus based on airborne transient electromagnetic method is disclosed, and includes a receiver coil, a transmitter coil, at least one compensation coil, and at least one compensation magnetic core, where the transmitter coil is disposed around a periphery of the receiver coil. The at least one compensation magnetic core is disposed around an outer surface of the transmitter coil. The at least one compensation coil is disposed around an outer surface of the compensation magnetic core.