Multi-Motor EV Powertrain Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle powertrains with single battery packs face challenges in maintaining battery balance and efficient regenerative torque, leading to inefficiencies and potential leakage currents, especially in vehicles requiring rapid torque changes and heavy loads.
Innovation Solution
A system with multiple motors sharing a common driveshaft, each powered by its own battery pack, allowing for selective engagement of motors for propulsion, regenerative braking, and charge balancing, utilizing a controller to optimize torque and state of charge across multiple battery packs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single battery pack is used to power all motors, then the system structure is simple, but the battery balance is difficult to maintain and regenerative charging efficiency is reduced
Solution Approach 1:
The patent divides the single battery pack into multiple independent battery packs, with each battery pack dedicated to powering specific motors. This segmentation allows independent management and balancing of each battery pack, resolving the battery balance issue while maintaining manageable system complexity through modular architecture.
2Device complexity
If a single battery pack is used, then manufacturing and control are simpler, but regenerative braking efficiency and energy recovery are insufficient
Solution Approach 1:
The system segments the powertrain into multiple motor-battery pairs, enabling independent regenerative braking control for each motor. During braking, multiple motors can simultaneously function as generators to charge their respective battery packs, significantly improving energy recovery efficiency while maintaining straightforward control logic for each independent unit.
3Reliability
If multiple battery packs with individual motors are used, then battery balance and regenerative charging are improved, but the system complexity and cost increase
Solution Approach 1:
The patent employs segmentation to create modular motor-battery units that can be independently managed. Each unit operates autonomously with its own control circuitry, simplifying the overall control architecture despite the increased number of components. This modular approach balances reliability improvement with acceptable system complexity.
Solution Approach 2:
The system design allows each motor-battery unit to perform multiple functions: propulsion, regenerative braking, and battery balancing. This multi-functionality reduces the need for additional dedicated components and control systems, thereby limiting the increase in system complexity while achieving improved battery balance and energy recovery.
4Speed
If rapid torque changes are needed for acceleration, then vehicle performance is improved, but battery discharge rate and thermal management challenges increase
Solution Approach 1:
The patent divides the total power demand across multiple independent battery packs and motors. During rapid acceleration, the system can draw power from multiple battery packs simultaneously, distributing the high discharge rate demand and reducing thermal stress on individual batteries. This segmentation enables high performance acceleration while managing thermal challenges through load distribution.
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 configuration enables efficient torque management, rapid acceleration, and smooth regenerative braking, particularly beneficial for heavy vehicles, by allowing instant torque adjustments and maintaining battery balance, thus enhancing overall powertrain efficiency and vehicle performance.
Implementation Method 1
a first motor (1) connected to a first battery pack (3) and configured to address the first wheel (17)
Implementation Method 2
the regenerative function can occur any time the motor rotation and torque are of opposite angular orientation
Data Source
AI summary
A powertrain for an electric vehicle has a driveshaft connected to two or more motors where each motor is connected to a battery pack associated with that motor. A controller is used to select one or more motors to be energized for propulsion or used for regenerative braking to recharge the battery pack to which it is coupled. The controller can optimize the state of charge (SOC) difference of the battery packs and provide for a smooth and efficient powering of the vehicle for acceleration and climbing and optimize the range of the vehicle by management of the relative SOC of the battery packs. The electric vehicle can include two or more fuel cells that individually coupled to a motor.