Air-Cooled Dynamo-Electric Machine Layout for Inverter Heat Isolation
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Solution Overview
Problem
Existing dynamo-electric machines with high current intensity and low voltage require efficient cooling solutions to manage high power losses in power electronics and conductor bars, especially in higher power classes (>0.5 MW).
Innovation Solution
A dynamo-electric machine design featuring a stator with hollow-cylindrical magnetically conductive body, conductors in grooves, and inverter modules, cooled by gaseous medium, with integral fans and closed or open cooling circuits, utilizing axial and radial air flows to cool conductor bars, short-circuit rings, and inverter modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If high current intensity is used in conductor bars to achieve compact construction and low voltage operation, then the machine size is reduced, but power losses and heat generation increase significantly
Solution Approach 1:
The conductor bars are divided into multiple parallel subconductors within each groove, which reduces current displacement effects and improves current distribution. Additionally, the machine is segmented into distinct cooling zones with separate cooling paths for stator conductors, rotor conductors, and power electronics modules, allowing optimized cooling for each high-loss component
Solution Approach 2:
A liquid cooling system is implemented using coolant channels with forced convection to efficiently remove heat from conductor bars and power electronics. The system includes coolant distributors, collectors, and temperature sensors to monitor and optimize cooling performance, directly addressing the heat generation problem from high current operation
2Volume of moving object
If compact construction is implemented with integrated power electronics and dynamo-electric machine, then space is reduced, but cooling requirements become more complex and challenging
Solution Approach 1:
The power electronics modules are integrated directly onto the stator core, eliminating the need for separate converter housings and external cooling systems. This merging of functions allows the cooling system to be unified and optimized for the combined heat sources, reducing overall system complexity despite the compact design
Solution Approach 2:
The liquid cooling system serves multiple functions simultaneously: it cools the conductor bars, cools the power electronics modules, and acts as an electrical insulator. The coolant channels are designed to provide both thermal management and electrical isolation, reducing the number of separate systems needed
3Use of energy by moving object
If high current intensity operation is implemented, then voltage requirements are reduced enabling compact construction, but heat transfer to inverter modules increases
Solution Approach 1:
The inverter modules are thermally isolated from the stator core by being mounted on a separate cooling plate with independent coolant channels. This extraction of the heat transfer path prevents heat from the high-current conductor bars from being transferred to the power electronics, allowing independent thermal management of each component
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 design effectively reduces power losses and heat transfer to inverter modules, enabling compact construction and efficient cooling under varying operating conditions.
Implementation Method 1
the conductors and/or the inverter modules and/or the rotor and/or the short-circuit ring of the stator can in each case be cooled, at least in sections, by means of a gaseous medium, in particular air
Implementation Method 2
liquid (in particular water) cooling systems have been designed for drives in the higher power range
Data Source
AI summary
A dynamo-electric rotary machine includes a stator having a hollow-cylindrical, magnetically conductive body, which has grooves in the region of an inner casing surface of the magnetically conductive body. Electrical conductors are received in the grooves and electrically contacted by a short-circuit ring on an end side of the magnetically conductive body of the stator. The electrical conductors are electrically contacted on another end side of the magnetically conductive body by a plurality of inverter modules for controlling the respective electrical conductor. A rotor is arranged spaced apart from the stator by an air gap and designed as a squirrel-cage rotor. The rotor has short-circuit rings on its end sides, wherein the conductors and/or the inverter modules and/or the rotor and/or the short-circuit ring of the stator can each be cooled, at least in a section thereof, by a gaseous medium, in particular air.