Electric Compressor Stator Layout to Limit Partial Discharge
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Solution Overview
Problem
Conventional electric compressors face durability issues when operating at high voltages due to partial electric discharge and moisture contamination, leading to reduced stator durability and increased risk of electric leakage from conductor wires.
Innovation Solution
The electric compressor design features a stator with coils connected in series, where specific coils are positioned above the shaft center to minimize immersion in lubricant oil and refrigerant, and the use of concentrated winding to reduce coil proximity and prevent partial discharge, along with sealed connectors to prevent moisture-induced leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If distributed winding is used to form coils in the stator, then the coils can be formed to accommodate high voltage requirements, but the coils are located close to each other causing partial electric discharge and reducing durability
Solution Approach 1:
The stator coils are segmented into two distinct groups: distributed windings positioned away from the shaft center for high voltage operation, and concentrated windings positioned near the shaft center for mechanical strength. This segmentation allows each group to fulfill its specific function without compromising the other.
Solution Approach 2:
The patent introduces a spatial dimension solution by arranging coils at different radial positions from the shaft center. The distributed windings are placed at larger radii while concentrated windings are placed at smaller radii, creating a radial dimension-based separation that resolves the contradiction between voltage requirements and durability.
2Temperature
If refrigerant is allowed to pass through the motor chamber to cool the electric motor, then cooling efficiency is improved, but lubricant oil accumulates in the motor chamber causing coils to be immersed and increasing electric leakage risk
Solution Approach 1:
Different regions of the motor chamber are assigned different functions: the region away from the shaft center is designated for cooling (allowing refrigerant flow), while the region near the shaft center is designated for electrical isolation (positioning coils above the liquid level). This local quality differentiation resolves the contradiction between cooling efficiency and electric leakage prevention.
3Reliability
If concentrated winding is used instead of distributed winding, then partial discharge is reduced and durability is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into two parts: the distributed windings can be manufactured using conventional methods, while the concentrated windings are manufactured separately and then assembled. This segmentation of the manufacturing process reduces overall complexity compared to manufacturing all concentrated windings from scratch.
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
This configuration enhances the compressor's durability by reducing the likelihood of electric leakage and maintaining performance under high voltage conditions, while also simplifying manufacturing and reducing costs.
Implementation Method 1
The electric motor includes a stator that is fixed in the motor chamber, and a rotor to which the drive shaft is fixed. The rotor is disposed in the stator and rotatable with the drive shaft around the shaft center of the drive shaft.
Implementation Method 2
The compression portion is disposed in the housing. In the housing, the motor chamber and the inlet port are separated by the compression portion. The compression portion is driven by the drive shaft to compress the refrigerant.
Data Source
AI summary
An electric compressor includes a housing, an electric motor, and an inverter. The housing includes a motor chamber. The electric motor includes a stator that includes a stator core, a plurality of first coils, a plurality of second coils, and a plurality of third coils. The first coils are connected in series, the second coils are connected in series, and the third coils are connected in series. One of the first coils that is located electrically closest to the first phase is referred to as a first specific coil, one of the second coils that is located electrically closest to the second phase is referred to as a second specific coil, and one of the third coils that is located electrically closest to the third phase is referred to as a third specific coil. The first to third specific coils are disposed above the shaft center of the drive shaft.