Stator Bar-Conductor Cooling for Compact Inverter Motor Heat Control
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Solution Overview
Problem
Electric motors with bar windings on the stator side face challenges in managing high current flow and heat dissipation due to low inductance, leading to increased cooling demands and component overheating.
Innovation Solution
Implement a cooling system with fluid pipes externally guided on field conductors, connected to cooling plates, and a pump for circulating coolant, which effectively dissipates heat and reduces the need for extensive cooling efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If bar windings are used on the stator side, then the inductance is reduced and current flow is increased, but heat loss and cooling requirements increase significantly
Solution Approach 1:
The cooling channels are extracted and integrated directly into the stator body structure, allowing heat to be removed from the source (field conductors) before it can be transferred to the electronic components on the printed circuit board. This extraction of the cooling function into the stator core resolves the heat loss problem by creating a dedicated heat removal path that does not depend on the proximity of electronic components.
Solution Approach 2:
The stator body acts as an intermediary thermal management component between the field conductors and the external cooling system. The integrated cooling channels within the stator serve as a mediator to transport heat away from the high-current field conductors, preventing direct heat transfer to the electronic components while still allowing the high current flow necessary for low-inductance operation.
2Device complexity
If high current flow is used to generate magnetic field, then inductance requirements are reduced, but heat dissipation from electronic components increases
Solution Approach 1:
The cooling function is extracted from the electronic component assembly and embedded directly into the stator structure. This allows heat dissipation to occur at the source (field conductors) rather than relying on cooling of the electronic components, thereby reducing the temperature rise of the power electronics while maintaining the simple low-inductance bar winding structure.
Solution Approach 2:
Heat is removed from the field conductors before it can be conducted to the electronic components on the printed circuit board. The integrated cooling channels in the stator perform preliminary heat extraction, preventing the compounding heat effect that would otherwise occur when both field conductors and electronic components are densely packed together.
3Productivity
If components are arranged at small spacings on printed circuit boards, then packing density is increased, but cooling effort required increases
Solution Approach 1:
The cooling function is taken out of the electronic component cooling domain and integrated into the stator's electromagnetic domain. This allows high packing density of electronic components on the printed circuit board to be maintained while the cooling effort is reduced, because the stator's integrated cooling channels remove heat at the source before it reaches the densely packed electronics.
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 cooling system enhances heat dissipation from field conductors and electronic components, allowing for a compact design with high packing density and reduced cooling requirements, even at low operating voltages.
Implementation Method 1
at least one cooling apparatus is present which comprises a fluid pipe (20, 60) which is externally adjacently guided on one or more of the field conductor(s) (12)
Implementation Method 2
a pump for a cooling fluid is present
Data Source
AI summary
Various embodiments of the teachings herein include an electric motor. An example includes: a stator having a plurality of bar-shaped field conductors; a plurality of inverters for actuating the field conductors; and a cooling apparatus including a fluid pipe externally adjacently guided on one or more of the field conductors. The inverters are arranged on one or more printed circuit boards arranged on at least one cooling plate. The at least one cooling plate is mechanically connected to the field conductors or conductors electrically connected to the field conductors.