Asynchronous Motor with Rotor Cooling and Wave Winding
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Solution Overview
Problem
Existing hybrid drive systems using asynchronous machines face performance limitations due to large installation space, high weight, low power density, and high costs associated with synchronous machines excited by permanent magnets, while also experiencing thermal load and efficiency issues.
Innovation Solution
An electric drive unit featuring an asynchronous machine with a squirrel cage rotor and wave winding stator, incorporating a star-delta switching function and rotor interior cooling, along with a transmission gearing system to optimize performance and reduce thermal losses, utilizing copper conductors for reduced ohmic resistance and mechanical strength, and a compact design to enhance efficiency and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an asynchronous machine with copper conductors is used, then thermal losses are reduced and operating temperature is lowered, but weight increases compared to aluminum conductors
Solution Approach 1:
The patent changes the material parameter from aluminum to copper conductors, exploiting copper's superior electrical conductivity to reduce ohmic losses. This parameter change directly addresses the thermal loss issue while accepting the weight trade-off, as copper's lower resistance compensates for the increased mass.
2Power
If a synchronous machine with permanent magnets is used, then power density and performance are improved, but cost increases due to expensive magnetic materials
Solution Approach 1:
The patent replaces expensive permanent magnets with a cost-effective asynchronous machine design using copper conductors and wave windings. While asynchronous machines traditionally have lower power density, the patent compensates through optimized winding configurations and cooling systems, achieving acceptable performance at significantly lower material costs.
Solution Approach 2:
The patent substitutes the electromagnetic field configuration of synchronous machines with permanent magnets against an asynchronous machine system using copper conductor windings. This substitution replaces expensive magnetic materials with more affordable copper-based electromagnetic induction, maintaining functional equivalence while reducing cost.
3Ease of manufacture
If an asynchronous machine is used, then cost and material availability are improved, but installation space and weight increase compared to synchronous machines
Solution Approach 1:
The patent places the transmission gearing system within the rotor structure of the asynchronous machine, nesting one functional system inside another. The planetary gears are integrated into the rotor interior, utilizing the rotational space efficiently and reducing the overall installation footprint of the electric drive unit.
Solution Approach 2:
The patent transitions from a two-dimensional comparison of motor types to a three-dimensional integrated design where the transmission system is embedded within the motor rotor volume. This spatial reorganization allows the asynchronous machine to achieve compact dimensions by utilizing internal rotor space for gear mechanisms.
4Volume of moving object
If a wave winding configuration is used, then installation space is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent changes the winding configuration parameter from conventional loop windings to wave windings. This parameter change reduces the number of winding turns and conductor length required, thereby reducing installation space and material usage, while the associated manufacturing complexity is managed through standardized production processes.
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 solution achieves improved output performance, reduced thermal load, and increased efficiency while minimizing installation space and production costs, allowing for stable operation across various rotational speeds and efficient energy utilization in hybrid drive systems.
Implementation Method 1
the rotor is configured with a rotor interior cooling device
Implementation Method 2
the particularly low, specific ohmic resistance of said copper conductors, as a result of which thermal power losses that occur during operation can be clearly reduced
Implementation Method 3
an asynchronous machine having a rotor that comprises a squirrel cage
Data Source
AI summary
An electric drive unit for a hybrid drive, in particular for a vehicle, has an increased power output and degree of efficiency, while thermal loading as well as required installation space and manufacturing costs are minimized. The electric drive unit has an asynchronous machine with a rotor with a rotor cage, in particular a rotor cage which is formed with copper conductors. The asynchronous machine is formed with a stator having a shaft winding. The shaft winding is formed with a device for star-delta changeover. The rotor is formed with a rotor internal cooling device. A step-up gear mechanism is arranged in a power train between the rotor and the output element. There is also described a hybrid drive device with an electric drive unit, and a vehicle that has an electric drive unit and/or a hybrid drive device.