Rotor Cooling Valve for Load-Dependent Coolant Flow
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Solution Overview
Problem
Conventional cooling systems for electric machines are inefficient in managing heat generated by the rotor, leading to reduced efficiency and reliability over the machine's service life, as they do not effectively adapt to varying load conditions.
Innovation Solution
A cooling system with a passive valve that controls coolant flow based on temperature, pressure, and rotational speed, utilizing Shape Memory Alloys (SMA) or diaphragms biased by elastic elements, to optimize coolant flow through a central cavity and transverse bores within the rotor shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional cooling systems with continuous coolant circulation are used, then the rotor is cooled, but the cooling system does not adapt to varying load conditions leading to reduced efficiency
Solution Approach 1:
The cooling system transitions from a static continuous circulation mode to a dynamic variable flow mode. The passive valve automatically adjusts the coolant flow rate based on real-time operating conditions (temperature, pressure, rotational speed), enabling the system to adapt its cooling capacity to match the actual thermal load of the rotor, thereby reducing energy waste during low-load operations.
Solution Approach 2:
The system employs a passive valve that automatically regulates coolant flow without requiring external control signals or additional energy input. The valve responds directly to physical parameters (temperature differences, pressure gradients, centrifugal forces) generated by the rotor's operation, allowing the cooling system to self-adjust and optimize its performance based on the rotor's actual cooling needs.
2Adaptability or versatility
If passive valves with multiple control mechanisms are used, then load point dependent cooling is achieved, but device complexity increases
Solution Approach 1:
The passive valve integrates multiple control functions (temperature response, pressure response, and rotational speed response) into a single compact component. Rather than using separate valves or control systems for each parameter, the invention combines these control mechanisms within one valve structure, reducing the overall number of parts and simplifying the system architecture while maintaining comprehensive load-dependent cooling control.
Solution Approach 2:
The passive valve is designed as a multi-functional component that simultaneously responds to multiple physical parameters (temperature, pressure, rotational speed) and performs flow regulation based on composite loading conditions. This universal design allows a single valve to handle various operating scenarios without requiring specialized components for each control function.
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 solution reduces mechanical and hydraulic losses, enhancing the efficiency and thermal availability of the electric machine by dynamically adjusting coolant flow according to the rotor's conditions.
Implementation Method 1
the passive valve has at least one SMA (Shape Memory Alloy) element for this purpose
Implementation Method 2
the passive valve has for this purpose a diaphragm or a plate that is biased against the direction of flow of the coolant via an elastic element
Implementation Method 3
the passive valve has for this purpose a ball that is biased against the centrifugal force due to the rotation of the rotor via an elastic element
Implementation Method 4
Due to its heat capacity, the coolant absorbs heat and transports it away
Data Source
AI summary
The present disclosure relates to a cooling system for load point dependent cooling of a rotor of an electric machine. The cooling system includes at least one coolant path extending at least partially into a rotor of an electric machine. At least one passive valve is arranged in the coolant path which regulates the flow rate of the coolant through the coolant path.