Alternator Stator Winding Pattern for High Voltage Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing alternators in off-highway vehicles face inefficiencies due to higher voltage requirements and lower engine speeds, leading to increased pressure and negative impacts on operation at high current, which affects fuel economy.
Innovation Solution
The alternator design features a stator with a main winding having unevenly arranged coils, with a 5-5-6 pattern of turns in each slot, and a tertiary excitation winding occupying a subset of slots, maximizing slot space usage and balancing performance between high voltage and high current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the number of turns within the slots of the stators is increased to meet higher voltage requirements at reduced engine speeds, then the voltage requirement is met, but operation at high current is negatively impacted
Solution Approach 1:
The patent applies local quality by creating different winding configurations in different slots. Specifically, some slots contain 5 turns while adjacent slots contain 6 turns, forming a 5-5-6 pattern. This non-uniform distribution optimizes the magnetic flux density locally in each slot, allowing the alternator to generate higher voltage at reduced engine speeds while maintaining proper current distribution and avoiding saturation, thus resolving the contradiction between voltage requirements and high current operation.
2Power
If the alternator is pushed to high saturation to meet higher voltage requirements, then voltage output increases, but efficiency and fuel economy are negatively impacted
Solution Approach 1:
The patent changes the physical parameter of winding turns distribution from uniform to non-uniform (5-5-6 pattern). This parameter change allows the alternator to achieve higher voltage output (up to 1800V) without pushing the magnetic core into high saturation. The optimized flux distribution reduces magnetic losses and improves overall efficiency, thereby maintaining fuel economy while meeting higher voltage requirements.
3Loss of energy
If the engine speed is reduced to improve engine efficiency, then engine efficiency improves, but the alternator faces additional pressure to generate higher voltage
Solution Approach 1:
The patent applies local quality through the 5-5-6 winding pattern where different slots have different numbers of turns. This creates optimized local magnetic circuits that enhance the alternator's voltage generation capability at reduced engine speeds. The non-uniform distribution compensates for the lower rotational speed by improving the electromagnetic induction efficiency in each slot, allowing the alternator to generate up to 1800V while the engine operates at more efficient lower speeds.
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 design improves alternator and drive system efficiency, enabling operation up to 1800V at reduced engine speeds, enhancing fuel economy and reducing stator and rotor current density without altering existing core or rotor designs.
Implementation Method 1
A typical alternator utilized in electric vehicles, such as mining OHVs, is a 10-pole synchronous generator that converts engine mechanical power to electrical power
Implementation Method 2
a single-phase tertiary winding to provide self-excitation of the alternator
Data Source
AI summary
A stator for an electric machine includes a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof, a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of slots in the stator core, and a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of slots in the stator core. The coils of the main winding are unevenly arranged in the plurality of slots.