Planetary EV Powertrain With Dual Motors for Continuous Torque
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Solution Overview
Problem
Electric vehicles face challenges in achieving maximum gradeability and maximum speed while reducing motor capacity, requiring improvements in power transfer efficiency and preventing torque interruption and shift shock.
Innovation Solution
A powertrain design for electric vehicles incorporating a planetary gear with three rotating elements, a first motor that supplies power at multiple gear ratios, and a second motor that selectively powers the first and second shafts, along with shift assemblies to manage power transmission and prevent torque interruption, utilizing a simple configuration to enhance efficiency and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If motor capacity is reduced to improve electrical efficiency, then drivable range increases, but maximum gradeability and maximum speed cannot be satisfied
Solution Approach 1:
The powertrain is segmented into two independent motors (first motor connected to first shaft, second motor connected to second shaft) that can operate independently or in combination. This allows the system to use only the necessary motor capacity for each driving condition, improving overall electrical efficiency while maintaining the ability to achieve maximum gradeability and speed when both motors operate together.
Solution Approach 2:
The system dynamically switches between different motor configurations and gear ratios based on driving conditions. The first motor can operate alone for efficiency, the second motor can supplement for performance, and both can work together for maximum power output. This dynamic adaptability resolves the contradiction between reduced motor capacity and maintained performance.
2Use of energy by moving object
If a transmission system is added to provide multiple gear ratios, then power transfer efficiency improves and motor capacity can be reduced, but device complexity increases
Solution Approach 1:
The transmission system is segmented into two independent shafts (first shaft and second shaft) with separate gear trains, allowing each shaft to handle specific gear ratio requirements. This segmentation enables efficient power transfer through simplified individual transmission paths while maintaining overall system performance.
Solution Approach 2:
The planetary gear mechanism serves multiple functions: it provides gear ratio transformation, enables differential power distribution between the two motors, and allows for various operating modes (first motor only, second motor only, or both together). This multi-functionality reduces the need for additional complex transmission components.
3Use of energy by moving object
If gear shifting is implemented to provide multiple shift ratios, then electrical efficiency improves, but torque interruption and gear shifting shock occur
Solution Approach 1:
The system maintains continuous torque delivery through multiple pathways: the first motor continuously drives the first shaft, the second motor continuously drives the second shaft, and the planetary gear mechanism continuously transforms and distributes power. This eliminates torque interruption during gear transitions, as there is no single point of disengagement.
Solution Approach 2:
The planetary gear mechanism dynamically adjusts power distribution between the two motors and shafts based on instantaneous driving conditions. This continuous dynamic adjustment eliminates the need for discrete gear shifting operations that cause torque interruption and shock, maintaining smooth and continuous power delivery across all operating ranges.
Data Source
AI summary
A powertrain for an electric vehicle includes: a planetary gear including a first rotating element, a second rotating element, and a third rotating element, where the first rotating element is connected to a first shaft, the second rotating element is connected to a second shaft, and the third rotating element is selectively connected to a transmission housing; a first motor supplying power to the first shaft at all times; and a second motor selectively supplying power to the first shaft and the second shaft. Two rotating elements among the first, second, third rotating elements of the planetary gear are selectively connected to integrally rotate the entire planetary gear.