Insulated Wire Dual-Layer Insulation High-Temperature Partial Discharge
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Solution Overview
Problem
Insulated wires used in high-voltage coils face increased partial discharge risks due to higher inverter surge voltages and high-temperature environments, which degrade the insulating covering layer, leading to performance issues and potential breakdowns.
Innovation Solution
An insulated wire design featuring a dual-layer insulating covering system with a first layer containing a resin with an imide group and a second layer made of polyimide, polyamide-imide, or polyester-imide resin, providing a high storage elastic modulus at elevated temperatures and controlled dielectric loss tangent, along with a lubricant layer for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space factor of the insulated wire is increased to downsize the motor, then the volume of the insulated wire is reduced, but the heat dissipation decreases and the operating temperature increases to 220°C or higher
Solution Approach 1:
The patent employs a composite insulating covering layer consisting of a first insulation layer (polymer alloy of polyphenylene sulfide and polyamide) and a second insulation layer (resin with specific elastic modulus characteristics). This composite structure provides both electrical insulation and thermal stability at elevated temperatures up to 220°C, enabling the insulated wire to maintain performance in high-temperature environments resulting from increased space factor.
2Power
If the inverter surge voltage is increased to improve performance, then the voltage level is raised, but the partial discharge occurrence increases
Solution Approach 1:
The dual-layer composite insulating covering structure provides enhanced electrical insulation properties that suppress partial discharge even at high inverter surge voltages. The specific combination of resin materials with controlled elastic modulus and dielectric properties creates a barrier against partial discharge initiation and propagation.
Solution Approach 2:
The patent specifies particular parameter ranges for the insulating materials, including storage elastic modulus at 20°C (not less than 1 GPa), storage elastic modulus at 200°C (not less than 10 MPa), and dielectric loss tangent (not more than 0.25). These parameter controls optimize the insulation's resistance to partial discharge under high voltage conditions.
3Ease of manufacture
If a conventional single-layer insulating covering is used, then the manufacturing process is simple, but the insulating wire cannot maintain high partial discharge inception voltage under high-temperature conditions
Solution Approach 1:
The insulating covering is divided into two distinct layers with different material compositions and functional characteristics. The first layer provides base insulation, while the second layer enhances high-temperature performance and partial discharge resistance. This segmentation allows each layer to be optimized for its specific function while maintaining manufacturability through sequential coating processes.
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 insulated wire maintains a high partial discharge inception voltage across ambient and high-temperature conditions, reducing the likelihood of discharge and ensuring reliable operation under severe environments, while also enhancing weldability and heat dissipation.
Implementation Method 1
an elastic modulus of the second insulation layer at 300° C. is not less than 300 MPa
Implementation Method 2
a relative permittivity of the insulating covering layer is not more than 3.0
Data Source
AI summary
An insulated wire includes a conductor, and an insulating covering layer including a first insulation layer formed around the conductor and a second insulation layer formed around the first insulation layer. An elastic modulus of the second insulation layer at 300° C. is not less than 300 MPa, and a relative permittivity of the insulating covering layer is not more than 3.0.