EESM Rotor Assembly With Centrifugal Oil Cooling for Heat Evacuation
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Solution Overview
Problem
Electric excited synchronous motors (EESMs) face limitations in heat evacuation due to indirect cooling systems, which restrict their performance as they replace high-power permanent magnet synchronous motors, necessitating more effective direct cooling systems.
Innovation Solution
A rotor assembly for EESMs featuring a direct oil cooling system utilizing centrifugal force to impulse cooling fluid through the rotor and end windings, with radial bores and axial channels connected to fluid guide elements that direct cooling fluid to the winding ends, allowing efficient heat dissipation without high pressure requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If indirect cooling systems (housing water jacket or air-cooling) are used in EESMs, then the structure is simple, but the heat evacuation capability is limited
Solution Approach 1:
The invention extracts the cooling function from the housing and creates dedicated cooling channels within the rotor shaft and rotor core. Cooling channels are formed directly in the rotor structure, allowing cooling fluid to flow through and directly remove heat from the rotor windings and core, separating the cooling function from the structural housing function.
Solution Approach 2:
The invention introduces cooling fluid as an intermediary substance to transfer heat from the rotor windings and core to the external cooling system. The cooling fluid flows through channels in the rotor shaft and rotor core, absorbing heat and carrying it away, thus mediating the heat transfer process more effectively than air or housing conduction.
2Temperature
If direct cooling systems are implemented to improve heat evacuation, then the cooling efficiency increases, but the system complexity increases
Solution Approach 1:
The invention merges the cooling system with the rotor structure by integrating cooling channels directly into the rotor shaft and rotor core. The cooling channels are formed as part of the rotor manufacturing process, combining the structural and cooling functions into a single integrated component, thereby reducing overall system complexity while achieving direct cooling.
Solution Approach 2:
The rotor structure serves multiple functions: it provides mechanical support for the windings, maintains magnetic circuit integrity, and simultaneously acts as a cooling fluid conduit. The rotor shaft and rotor core are designed to perform both structural and thermal management functions, reducing the need for separate cooling components.
3Quantity of substance
If high pressure is used to impulse cooling fluid through the rotor, then the cooling fluid flow is improved, but the pressure requirements and system complexity increase
Solution Approach 1:
The invention utilizes the dynamic rotation of the rotor to generate centrifugal force, which dynamically drives the cooling fluid through the cooling channels. As the rotor rotates, the centrifugal force automatically propels the cooling fluid from the rotor shaft through the rotor core and out through the escape openings, eliminating the need for high pressure pumps or complex pressurization systems.
Solution Approach 2:
The rotating rotor itself serves as the driving mechanism for the cooling fluid flow. The centrifugal force generated by the rotor's own rotation is sufficient to impulse the cooling fluid through the channels and onto the windings, making the system self-sufficient and eliminating external high-pressure sources.
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 enhances cooling efficiency and extends the service life of EESMs by effectively distributing cooling fluid and heat across the rotor assembly, addressing the limitations of traditional cooling systems.
Implementation Method 1
A rotor assembly for an electric excited synchronous motor (EESM) can be provided with a direct oil cooling system, which uses a centrifugal force caused by a rotation of the rotor to impulse cooling fluid
Data Source
AI summary
A rotor assembly for an electric excited synchronous motor (EESM) comprises: a rotor shaft, a rotor core with windings, a first and a second fluid guide element arranged at the ends of the rotor core, wherein the rotor shaft comprises an axial bore and a plurality of radial bores, wherein the rotor core includes a plurality of inlet openings fluidically connected to the radial bores, and axial channels extending axially to first and second outlet openings of the rotor core, wherein the first and second fluid guide elements are fluidically connected to the outlet openings of the rotor core and comprise a fluid structure configured to receive cooling fluid from the rotor core and guide same to escape openings arranged in circumferential direction between two circumferentially adjacent winding ends of the rotor.