Short Circuit Detection for Electromagnetic Induction Coils
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Solution Overview
Problem
Existing methods for detecting short circuits in electromagnetic induction coils require the primary coil to be active, pose safety risks, and are complex, unreliable, and require knowledge of resonance frequencies, which are influenced by parasitic capacitances.
Innovation Solution
A detection device with a separate detection coil and circuit that induces a current in the electromagnetic induction coil, allowing for short circuit detection without activating the coil, using a change in inductance and frequency analysis to distinguish types of short circuits, and operating at a low voltage to ensure safety and reduce hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate sensing coil or hall device is used to detect short circuit, then short circuit detection capability is improved, but the primary coil must remain active which increases safety risks and operational complexity
Solution Approach 1:
The detection coil is positioned and configured in advance to detect changes in the electromagnetic field of the induction coil before the induction coil is activated. This allows short circuit detection to occur in a static state, eliminating the need for the primary coil to remain active during detection, thereby reducing safety risks while maintaining detection capability
2Reliability
If transfer function measurement near resonance frequency is used, then short circuit detection is achieved, but knowledge of resonance frequency is required and parasitic capacitances heavily influence the measurement
Solution Approach 1:
A detection coil is introduced as an intermediary element that indirectly senses the state of the induction coil through electromagnetic coupling. Instead of directly measuring the transfer function of the induction coil (which requires knowledge of resonance frequency and is sensitive to parasitic capacitances), the detection coil measures changes in its own inductance caused by the induction coil's state, simplifying the measurement process and eliminating the need for resonance frequency knowledge
3Measurement precision
If the electromagnetic induction coil is driven to detect short circuit, then detection accuracy is improved, but hardware complexity and costs increase
Solution Approach 1:
The induction coil itself generates the electromagnetic field that the detection coil measures. By positioning the detection coil to sense the electromagnetic field produced by the induction coil during its normal operation, the system uses the induction coil's own operational characteristics for detection purposes. This eliminates the need for separate excitation sources and complex test equipment, reducing hardware complexity while maintaining detection accuracy
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
Enables safe, reliable, and efficient detection of short circuits without driving the electromagnetic induction coil, allowing for discrimination between different types of short circuits and reducing hardware requirements and costs by using low-voltage components and frequency-based measurements.
Implementation Method 1
The detection coil is arranged such that the detection coil is inductively coupled to the at least one electromagnetic induction coil
Implementation Method 2
The detection circuit is configured to drive the detection coil in order to induce an electric current in the at least one electromagnetic induction coil
Data Source
Figure 1~2
Figure 3~4
Figure 5A~6
AI summary
Apparatus (10, 20), comprising at least one electromagnetic induction coil (Lp1-Lpx), and a detection device (12, 22) for detecting a short circuit in the at least one electromagnetic induction coil. The detection device comprises a detection coil (Ls1-Lsx) independent of the at least one electromagnetic induction coil and a detection circuit (121) coupled to the detection coil. The detection coil (Ls1-Lsx) is arranged such that the detection coil is inductively coupled to the at least one electromagnetic induction coil (Lp1-Lpx). The detection circuit (121) is configured to drive the detection coil (Ls1-Lsx) in order to induce an electric current in the at least one electromagnetic induction coil (Lp1-Lpx). The detection circuit is configured to determine a frequency of an electric signal induced in the detection coil (Ls1-Lsx) by the electric current.