Electric Vehicle Traction Control via Direct Current Modulation
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Solution Overview
Problem
Existing traction control systems are ineffective for electric vehicles and aircraft powered by electric drive motors, as they rely on speed measurements and engine control, failing to directly control current supply to maintain maximum traction and address slipping conditions effectively.
Innovation Solution
A traction control system that directly controls the current supply to an electric motor driving vehicle wheels, maintaining maximum current for operator-commanded speed and modulating torque/speed relationships to manage wheel speed and traction, independent of speed measurements, suitable for electric vehicles and aircraft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing traction control systems use speed measurements and engine control, then they can control traction in conventional vehicles, but they are ineffective for electric vehicles powered by electric drive motors
Solution Approach 1:
The patent replaces traditional mechanical/engine-based control systems with an electric motor control system. Instead of using engine throttle control and speed measurements, the system directly controls the electric motor's current supply to regulate wheel torque and maintain traction, adapting the control mechanism to the electric powertrain architecture.
Solution Approach 2:
The system changes the control parameter from engine speed/throttle position to electric motor current supply. By monitoring and adjusting the current supplied to the electric motor, the system directly controls the torque output to prevent wheel slip, thereby adapting conventional traction control concepts to electric vehicle applications.
2Productivity
If maximum current is supplied to the electric motor, then maximum torque and acceleration are achieved, but wheel slip occurs on low-friction surfaces
Solution Approach 1:
The system implements feedback control by continuously monitoring wheel rotation speeds and comparing them to expected speeds based on vehicle acceleration demands. When slip is detected (actual speed exceeds expected speed), the system reduces the current supply to the electric motor, thereby reducing torque and eliminating the slip, thus maintaining both acceleration performance and traction stability.
Solution Approach 2:
The system dynamically adjusts the current supply to the electric motor based on real-time traction conditions. Rather than maintaining a fixed current level, the control system continuously modulates the current to optimize the balance between acceleration performance and preventing wheel slip, adapting to changing surface conditions and vehicle states.
3Reliability
If conventional braking systems are used for traction control, then wheel speed can be reduced, but the system complexity increases and response time is delayed
Solution Approach 1:
The patent extracts the traction control function from the conventional braking system and integrates it directly into the electric motor control system. By using the motor controller to regulate current supply for traction control, the system eliminates the need for separate braking intervention, reducing overall system complexity while maintaining effective traction control capability.
Solution Approach 2:
The system merges the traction control function with the existing electric motor control system. The same controller that manages motor operation for acceleration also handles traction control by modulating current supply, combining multiple functions into a single integrated system, thereby reducing complexity and improving response time compared to separate braking-based systems.
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 ensures optimal traction control across various ground surfaces and environmental conditions, reducing wheel slip and maintaining vehicle stability without relying on antilock braking systems, effectively managing traction in electric vehicles and aircraft.
Implementation Method 1
an electric motor driving vehicle wheels
Implementation Method 2
Traction of a vehicle is established as its wheels contact a surface so that when the wheels are rotated, usually by a driving force, the vehicle will be moved along the surface in a desired direction. The combination of the coefficient of friction and the force exerted by a wheel against the surface produces traction.
Data Source
AI summary
A traction control system and method are provided for electric vehicles with at least one drive wheel powered by an electric drive motor to maintain optimum maximum traction while the vehicle is driven on the ground. The traction control system includes drive means capable of transmitting torque through a vehicle drive wheel and controllable to move the vehicle over a ground surface. A preferred drive means is an electric motor designed to move the vehicle at desired ground speeds in response to operator input. Operator input requests a desired speed, and the system determines drive wheel torque required to produce the desired speed and provides maximum current to produce maximum torque to drive the vehicle with optimum traction at the desired speed. The system uses constant feedback to find maximum current corresponding to torque required for an inputted speed request to automatically control traction in any electric powered vehicle.