Partial Discharge Monitoring Using Magnetic Field Sensors
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Solution Overview
Problem
Existing electrical systems face challenges in effectively monitoring partial discharge events within electrical devices due to insulation degradation, which can lead to reduced reliability, especially in aircraft systems, where internal monitoring is complicated by the size of high-frequency capacitors.
Innovation Solution
A motor controller electrical device with a partial discharge monitoring system that includes a sensor with multiple coils, both straight and enclosed, arranged within the housing to detect radio frequency electromagnetic fields, providing galvanic isolation and minimizing invasiveness, while maintaining the electromagnetic interference signature of the device unchanged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency capacitors are used for internal monitoring, then partial discharge detection capability is improved, but device size and complexity increase
Solution Approach 1:
The patent replaces the conventional capacitive sensing mechanism with a magnetic field-based detection system using coils and a magnetometer. This substitution eliminates the need for large high-frequency capacitors while maintaining partial discharge detection capability, as magnetic field sensors can detect the electromagnetic signals generated by partial discharge events without requiring bulky capacitive components.
Solution Approach 2:
The invention changes the detection parameter from capacitive coupling to magnetic field sensing. By using a magnetometer to detect changes in the magnetic field caused by partial discharge events, the system achieves effective monitoring without the size constraints of capacitive-based high-frequency capacitors.
2Reliability
If monitoring systems are added to detect insulation degradation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex capacitive monitoring circuits with a simpler magnetic field-based detection system. The magnetometer and coil arrangement provides a more straightforward implementation that reduces circuit complexity while maintaining the ability to detect partial discharge events and monitor insulation degradation.
Solution Approach 2:
The monitoring system leverages the existing electromagnetic field environment within the electrical device. The coils and magnetometer utilize the natural magnetic field variations caused by partial discharge events without requiring additional power-intensive active sensing circuits, thereby reducing overall system complexity.
3Measurement precision
If sensors are placed inside the housing, then detection sensitivity is improved, but electromagnetic interference increases
Solution Approach 1:
The patent substitutes capacitive sensors with magnetic field-based magnetometer sensors. Magnetic field sensors are inherently less susceptible to electromagnetic interference from power electronics compared to capacitive sensors, as they detect magnetic field variations rather than voltage signals, thereby maintaining detection sensitivity while reducing EMI vulnerability.
Solution Approach 2:
The coils act as intermediaries between the partial discharge events and the magnetometer sensor. The coils convert the electromagnetic signals from partial discharge into magnetic field variations that the magnetometer can detect, providing isolation between the high-interference power electronics environment and the sensitive sensing element.
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 online Corona detection with minimal weight and complexity increase, ensuring early indication of insulation breakdown and allowing for scheduled maintenance, thereby enhancing the reliability of electrical systems.
Implementation Method 1
the coil is a sensor configured to generate a signal responsive to a radio frequency electromagnetic field
Data Source
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Figure 3~4
AI summary
An electrical device (100) includes a housing (104) defining a chamber, a power converter (114) arranged within the chamber, and a sensor (102). The sensor includes a coil arranged within the chamber and in radio frequency communication with the power converter to detect partial discharge of a voltage potential applied to the power converter. Health monitoring systems and health monitoring methods are also described.