Stator Chamber Thermoelectric Cooling for Variable-Torque Electric Machines
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Solution Overview
Problem
Conventional electric generators and motors operate inefficiently when operating outside their rated rotational speed (RPM) and torque due to fixed magnetic fields and stator windings, leading to significant efficiency drops in variable torque and speed conditions common in renewable energy and hybrid vehicles.
Innovation Solution
A cooling system for electric machines that includes a sealed stator core with circulating coolant and thermoelectric devices to manage temperature and dynamically adjust magnetic fields using tunable Halbach magnet arrays and series/parallel coil switching, enhancing efficiency under variable torque and speed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electric generators and motors operate outside their rated rotational speed and torque, then they can adapt to variable operating conditions, but their efficiency decreases dramatically
Solution Approach 1:
The patent implements dynamic adjustment of magnetic field strength through variable reluctance mechanisms and adjustable air gaps between rotor and stator. This allows the magnetic circuit to adapt its reluctance characteristics in real-time, optimizing the balance between magnetic flux and mechanical losses across different operating points, thereby maintaining high efficiency throughout a wide operating range
Solution Approach 2:
The system dynamically changes key parameters including air gap length, magnetic circuit reluctance, and winding configuration (series/parallel switching). These parameter adjustments allow the generator/motor to optimize its electromagnetic characteristics for different operating conditions, preventing the dramatic efficiency drops that occur in conventional fixed-parameter designs
2Loss of energy
If conventional electric generators and motors are designed for continuous rotation and constant torque, then they achieve high efficiency (90%-98%) at rated conditions, but they cannot handle variable torque and speed conditions effectively
Solution Approach 1:
The patent employs dynamic control of the magnetic circuit through variable reluctance mechanisms that adjust the magnetic path resistance in real-time. This dynamic adjustment allows the system to maintain optimal magnetic flux density and minimize core losses across varying torque and speed conditions, enabling high efficiency in variable operating modes while maintaining adaptability
Solution Approach 2:
The system is designed to perform multiple functions within a single device: it can operate as both a generator and motor, handle both constant and variable torque conditions, and adapt to different rotational speeds. The universal design incorporates adjustable magnetic circuits and reconfigurable windings that enable the device to maintain high efficiency across all these operating modes
3Loss of energy
If thermoelectric devices are added to convert waste heat into electricity, then energy recovery is improved, but device complexity increases
Solution Approach 1:
The patent integrates thermoelectric energy harvesting devices directly into the existing cooling system architecture. The thermoelectric modules are positioned to utilize the temperature differential already present in the cooling fluid path, merging the waste heat recovery function with the thermal management system rather than adding a completely separate subsystem, thereby limiting the increase in overall system complexity
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 system maintains high efficiency by reducing coil resistance, allowing increased amperage and power output, and converts waste heat into electricity, improving performance in variable torque and speed applications.
Implementation Method 1
thermoelectric devices positioned around the circumference of the stator core in contact with the coolant to convert waste heat from the stator core into electric current
Implementation Method 2
A coolant is circulated throughout the sealed stator chamber to remove heat from the stator core
Data Source
AI summary
An electric machine having a housing with a stator chamber, an axle supported by at least one bearing assembly so that the axle may rotate with respect to the housing, a stator assembly with a stator core and a plurality of wire windings around the stator core, a rotor assembly with a magnet assembly for generating a magnetic field in the stator assembly wherein a coolant is circulated through the stator chamber over the stator core and plurality of wire windings to remove heat, and a plurality of thermoelectric devices. The thermoelectric devices are located around the inner circumference of the housing so that the coolant is circulated over the plurality of thermoelectric devices. The plurality of thermoelectric use the Peltier effect to cool the coolant flowing through the stator chamber or generate an electrical current that can be used by the electric machine.