Conductive Coil Insulation Layer to Prevent Partial Discharge
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Solution Overview
Problem
The increasing performance of electric machines leads to higher stress on electrical insulation, increasing the risk of system failures due to partial discharges, especially in safety-critical environments like aircraft drive systems, where air inclusions in insulation systems compromise the machine's lifetime and detection of insulation degradation is challenging.
Innovation Solution
A coil arrangement with an insulating arrangement that includes a conductive layer between the coil turns and the electrically conductive elements, such as a laminated core or tooth, ensuring the same electrical potential and preventing partial discharges by grounding the conductive layer, thereby reducing the risk of short-circuits and allowing for timely detection of insulation faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional impregnating processes are used to insulate coil turns, then manufacturing simplicity is maintained, but air inclusions remain in the insulation system creating weak points for partial discharges
Solution Approach 1:
The patent applies composite materials by combining multiple insulating layers with different properties: a first insulating layer (e.g., varnish) applied directly to the conductor, a second insulating layer (e.g., tape or film) wrapped around the first layer, and optionally a third insulating layer. This multi-layer composite structure provides more comprehensive coverage and eliminates air inclusions that would be present in conventional single-layer impregnating processes, thereby improving reliability without requiring complex manufacturing changes.
2Power
If the machine is designed for high power density, then performance capability increases, but electrical insulation stress increases leading to higher failure risk
Solution Approach 1:
The patent implements beforehand cushioning by applying multiple protective insulating layers to the coil turns before the machine operates. The first insulating layer is applied directly to the conductor surface, followed by a second layer that provides additional protection. This pre-established multi-layer insulation system cushions against the high electrical stress and partial discharges that occur during high power density operation, preventing insulation breakdown and maintaining reliability under increased power conditions.
3Reliability
If air inclusions are completely eliminated from the insulation system, then partial discharge resistance improves, but manufacturing process complexity increases significantly
Solution Approach 1:
The patent applies local quality by providing enhanced insulation coverage at critical locations where air inclusions are most likely to form and cause problems. The first insulating layer is applied directly to the conductor surface at the turn level, and the second insulating layer is wrapped around specific sections. This localized multi-layer approach targets the most vulnerable areas without requiring complex insulation throughout the entire machine, thereby improving partial discharge resistance with moderate complexity increase.
4Measurement precision
If insulation resistance monitoring is used to detect conductor-ground insulation degradation, then some insulation deterioration can be detected, but conductor-conductor insulation faults cannot be reliably predicted or detected
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the earthed component as a reference point for detecting both conductor-ground and conductor-conductor insulation faults. The monitoring system measures insulation resistance between each conductor and the earthed component, which serves as an intermediary reference that enables detection of all insulation degradation types. This intermediary measurement method provides comprehensive fault detection capability without requiring direct measurement between conductors.
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 solution significantly enhances operational reliability by preventing partial discharges and allowing for the assessment of insulation condition, reducing the risk of machine failure and enabling early detection of potential faults, thus improving safety and performance.
Implementation Method 1
The insulating arrangement has a first, electrically conductive layer (151), which is to be arranged between the turn to be insulated (122‑i‑k) of the coil conductor (122‑i) and that electrically conductive element (123‑i) from which the turn to be insulated (122‑i‑k) is to be insulated, wherein the first layer (151) is electrically connectable to the electrically conductive component (129)
Data Source
AI summary
The disclosure relates to an electric machine of an electrical system, (e.g., a drive system), and in particular to the electrical insulation of a coil of the machine. A coil arrangement includes a coil, formed by an electrical coil conductor, and also an insulating arrangement. The coil is arranged at an electrically conductive element of the machine, for example, at or on a corresponding tooth of a stator or of a rotor of the machine, which is formed by a laminated core. The insulating arrangement is configured to insulate the coil from the electrically conductive element, (e.g., from the laminated core forming the tooth). The insulating arrangement has a first, electrically conductive layer, which is at least partly arranged between the coil and the metallic component. Furthermore, the first layer is electrically connected to the metallic component, in order to prevent partial discharges between the insulating arrangement and the metallic component.