High-Current-Density Electric Machine With Integrated Pressure Cooling
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Solution Overview
Problem
Electric machines used in large industrial and marine applications face challenges in achieving high current and power densities while maintaining efficient cooling, especially in synchronous generators and motors that operate at various speeds and loads.
Innovation Solution
The implementation of a high-pressure cooling system that actively cools both the stator and rotor windings, utilizing a closed system with high-pressure fluid circulation to enhance current density and power density, and the placement of an excitation system within the stator housing to support rotor rotation and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current density is implemented in stator and rotor windings, then power density and efficiency are improved, but heat generation increases requiring more complex cooling systems
Solution Approach 1:
The patent implements a hydraulic cooling system using high-pressure fluid circulation through channels in the stator and rotor. The cooling fluid is pumped at high pressure through manifolds distributed across the windings, enabling efficient heat removal from high current density operations without requiring complex external cooling infrastructure
Solution Approach 2:
The cooling system is integrated directly into the stator and rotor structures by embedding cooling channels within the winding assemblies themselves. This merging of cooling functionality into the structural components eliminates separate cooling systems and reduces overall complexity while maintaining effective heat dissipation
2Reliability
If active cooling systems are added to maintain high current density, then operational reliability is improved, but device complexity increases
Solution Approach 1:
The cooling system utilizes the machine's own operational characteristics - the rotating rotor and stator structures - to facilitate self-cooling through integrated channels. The high-pressure fluid system is activated during normal operation, allowing the machine to cool itself without requiring external cooling infrastructure or additional control systems
Solution Approach 2:
A high-pressure hydraulic system provides reliable cooling through forced circulation of coolant through embedded channels. The high pressure ensures adequate flow rate and heat transfer coefficient, maintaining operational reliability through simple, robust hydraulic components rather than complex thermal management systems
3Temperature
If high-pressure cooling fluid circulation is implemented, then heat dissipation is improved, but energy consumption increases
Solution Approach 1:
The cooling system is divided into separate stator and rotor cooling circuits, each with dedicated high-pressure fluid circulation. This segmentation allows independent optimization of cooling requirements for each component, ensuring efficient heat dissipation only where needed and minimizing overall energy consumption by avoiding unnecessary cooling of non-critical areas
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 allows for electric machines to operate with current densities exceeding 5 A/mm2 and power densities up to 1.0 kW/kg, effectively addressing the efficiency and cooling challenges in high-power applications from 1 MW to 50 MW.
Implementation Method 1
A high-pressure cooling system is operable to actively cool the stator and the rotor
Implementation Method 2
The stator has a stator current density of greater than 5 A/mm2. A rotor has a rotor current density of greater than 5 A/mm2. A high-pressure cooling system is operable to actively cool the stator and the rotor
Implementation Method 3
The rotor winding and the stator winding interact to one of produce rotation of the rotor to drive a connected device in response to the receipt of the electrical current and produce the electrical current in response to rotation of the rotor driven by the connected device
Data Source
AI summary
An electric machine includes a stator having a stator bore and a stator winding. The stator winding is arranged to one of receive an electrical current and produce an electrical current having a power between 1 MW and 50 MW. The stator has a stator current density of greater than 5 A/mm2. A rotor is at least partially disposed within the stator bore and has a rotor winding. The rotor has a rotor current density of greater than 5 A/mm2. A high-pressure cooling system is operable to actively cool the stator and the rotor. The rotor winding and the stator winding interact to one of produce rotation of the rotor to drive a connected device in response to the receipt of the electrical current and produce the electrical current in response to rotation of the rotor driven by the connected device.