Drive Axle Control for Regenerative Power Overcharge Prevention
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Solution Overview
Problem
Electrified vehicles face challenges in managing regenerative power generated during motion and braking, particularly when the vehicle is not requesting propulsion or braking, due to poor torque accuracy in drive axle systems, leading to potential overcharging of the electric power source.
Innovation Solution
A method and system that control the drive axle system by providing electrical energy from an electric power source to an electric motor to offset regenerative power, determining if the vehicle is in motion and zero torque is requested, and applying propulsion torque to counteract regenerative power when it cannot be absorbed by the power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative power is absorbed by the electric power source during motion without propulsion or braking requests, then energy recovery is improved, but overcharging of the electric power source occurs
Solution Approach 1:
The controller continuously monitors the regenerative power generated by the electric motor and compares it with the absorption capacity of the electric power source. When the power source cannot absorb the generated regenerative power, the controller activates the electric motor to provide propulsion torque that counteracts the regenerative power, preventing overcharging while maximizing energy recovery
2Reliability
If the electric motor provides propulsion torque to counteract regenerative power, then overcharging is prevented, but energy efficiency deteriorates due to energy consumption from the power source
Solution Approach 1:
The system converts the potentially harmful regenerative power that would cause overcharging into a beneficial force by using the electric motor to counteract it. The regenerative power is not wasted but rather balanced by controlled propulsion torque, transforming a problem into a solution that maintains system reliability while minimizing energy loss
3Ease of manufacture
If drive axle systems use poor torque accuracy components to reduce cost, then manufacturing cost is reduced, but regenerative power management precision deteriorates
Solution Approach 1:
The system uses the electric motor's own propulsion torque capability to self-correct the imprecision caused by poor torque accuracy in the drive axle system. By dynamically adjusting the propulsion torque to counteract regenerative power, the system compensates for measurement inaccuracies without requiring high-precision torque sensors or expensive components
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 approach effectively manages regenerative power, preventing overcharging and ensuring efficient energy handling, even with systems having poor torque accuracy, thereby accommodating drive axle systems with reduced costs and improved operational reliability.
Implementation Method 1
regenerative power that is generated by the electric motor when the vehicle is in motion and braking
Implementation Method 2
providing electrical energy from an electric power source to the electric motor to offset regenerative power
Data Source
Figure 1
Figure 2
AI summary
A vehicle having a drive axle system and a method of control. Electrical energy is provided from an electric power source to an electric motor to offset regenerative power generated by the electric motor when the vehicle is in motion and braking and acceleration of the vehicle are not requested.