Electric Machine Rectifier Cooling Airflow Path Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical machines with rectifier devices face inefficiencies in cooling air flow distribution due to the overlapping arrangement of positive and negative heat sinks, leading to uneven cooling of diodes and potential preheating issues.
Innovation Solution
The electrical machine design incorporates a connection plate between the positive and negative heat sinks, optimizing the air flow path to ensure effective cooling of negative diodes without preheating, by maintaining a specific distance and arrangement that prevents air flow throttling and ensures efficient cooling air distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the positive and negative heat sinks are arranged directly on top of each other in an overlapping configuration, then the compactness of the rectifier device is improved, but the cooling air flow distribution becomes uneven and preheating of negative diodes occurs
Solution Approach 1:
A connection plate is introduced as an intermediary element between the positive and negative heat sinks. This connection plate serves multiple functions: it provides mechanical support for the diodes, creates a defined air flow path, and prevents direct thermal coupling between the positive and negative heat sinks that would cause preheating. The connection plate acts as a thermal barrier while maintaining structural integrity and enabling compact arrangement.
Solution Approach 2:
The rectifier device is segmented into distinct functional zones by the connection plate, which separates the positive diode assembly from the negative diode assembly. This segmentation allows independent thermal management of each diode type, ensuring that cooling air flows independently to each heat sink without mixing hot and cold air streams. The segmentation resolves the contradiction by maintaining compactness while preventing thermal interference.
2Temperature
If cooling air openings are provided in the protective cap, then cooling of the rectifier device is improved, but air flow throttling occurs due to the overlapping heat sink arrangement
Solution Approach 1:
The connection plate serves as a mediator that organizes the air flow path from the cooling openings in the protective cap to the respective heat sinks. It directs cooling air to flow first to the negative heat sink and then to the positive heat sink, preventing air flow throttling by creating unobstructed flow paths. The connection plate's geometry is designed to guide air flow efficiently without creating restrictions.
Solution Approach 2:
The connection plate creates localized air flow channels with specific geometries optimized for each heat sink. The air flow path is designed with different characteristics for cooling the negative diodes versus the positive diodes, allowing each region to receive appropriate cooling air flow. This local optimization ensures high cooling efficiency without overall air flow throttling.
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 enhances the cooling efficiency of negative diodes while preventing preheating from positive diodes, resulting in improved thermal management and performance of the electrical machine.
Implementation Method 1
a cooling air flow 115 is generated which flows essentially turbulence-free between the connection plate 56 and the negative heat sink 106 as well as between the closing protective cap 47 and the plus heat sink 53
Implementation Method 2
the positive diodes being connected (plugged in or soldered) to a positive heat sink and the negative diodes to a negative heat sink
Data Source
Figure 2~2a
Figure 3
Figure 4a
AI summary
An electric generator, comprising a stator and a rotor, the stator having a stator winding (multiple phase windings), which is electrically connected to a rectifier, the rectifier having positive and negative diodes connected by way of a bridge circuit, the positive diodes being connected to a positive cooling body and the negative diodes being connected to a negative cooling body (plugged in or welded), and the rectifier being covered by a protective cap (47) having cooling air openings, characterized in that the protective cap has at least one opening, which is disposed axially above the negative diode and the negative cooling body.