Rotor Cooling Section for Active Rectifier Heat Dissipation
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Solution Overview
Problem
In externally excited synchronous machines used as traction motors, the active rectifier on the rotor generates significant heat, limiting the maximum power output, and existing cooling systems are inadequate for effectively managing this heat.
Innovation Solution
An active rectifier is integrated onto a cooling section of the rotor, which serves as a heat sink, and a cooling fluid flows through it, enhancing thermal dissipation. This setup includes a baffle to convert laminar flow into turbulent flow, and a thermally conductive medium ensures efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an active rectifier is used on the rotor to convert alternating voltage to direct voltage, then the control flexibility and efficiency of the electric machine are improved, but significant heat is generated which limits the maximum power output
Solution Approach 1:
The rectifier is merged with the rotor structure by mounting it directly on the rotor's cooling section, integrating the heat-generating component with the heat dissipation system. This eliminates the need for separate cooling arrangements and enables direct thermal coupling between the rectifier and cooling fluid pathway.
Solution Approach 2:
A cooling fluid acts as an intermediary medium to transfer heat from the rectifier to the external cooling system. The cooling fluid flows through channels in the rotor's cooling section, absorbing thermal energy from the rectifier and carrying it away to maintain operational temperatures.
2Temperature
If the rectifier is mounted on the rotor, then the thermal coupling with the heat sink is improved, but the device complexity increases due to integration requirements
Solution Approach 1:
The rotor structure is designed to serve multiple functions: it provides mechanical rotation support, houses the cooling fluid channels, and mounts the rectifier component. The cooling section of the rotor acts as both a structural element and a heat sink, eliminating the need for dedicated cooling hardware and reducing overall system complexity.
Solution Approach 2:
The rotor's cooling section serves its own cooling needs and simultaneously provides cooling for the mounted rectifier. The cooling fluid pathways are integrated into the rotor structure itself, allowing the rotor to self-regulate its temperature while also managing the thermal load of the rectifier through direct thermal coupling.
3Temperature
If cooling fluid channels are integrated into the rotor structure, then the cooling efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The rotor is divided into functional sections, including a dedicated cooling section with integrated fluid channels. This segmentation allows the cooling pathways to be designed as distinct features within the rotor structure, enabling modular manufacturing approaches and simplifying the creation of complex internal channel geometries.
Solution Approach 2:
Cooling fluid channels are integrated directly into the rotor structure, utilizing hydraulic principles to circulate cooling fluid through the rotor and rectifier assembly. The channels are designed to optimize fluid flow patterns for efficient heat removal, with inlet and outlet ports positioned to maximize thermal exchange while maintaining structural integrity.
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 integrated rectifier on the rotor's heat sink effectively dissipates heat, allowing for higher power generation and improved operational efficiency by managing the heat generated by the active rectifier.
Implementation Method 1
a thermally conductive medium ensures efficient heat transfer
Implementation Method 2
a baffle to convert laminar flow into turbulent flow
Implementation Method 3
rotor windings for generating a rotor magnetic field
Data Source
AI summary
An electric machine for a motor vehicle is disclosed, and may include a stator, a rotor rotatably mounted with respect to the stator and having rotor windings for generating a rotor magnetic field, and an active rectifier provided on the rotor. The active rectifier may electrically connect a voltage source present on the rotor to the rotor windings, and may be configured to convert an alternating voltage provided by the voltage source into a direct voltage. The direct voltage may be configured to be utilized during generation of the rotor magnetic field by the rotor windings. The active rectifier may be arranged on or in a cooling section of the rotor. The cooling section may form a heat sink through which a cooling fluid can flow.