Electric Drive Vehicle Towing Control Logic
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Solution Overview
Problem
Electric-drive vehicles face damage risks during towing due to uncontrolled voltage and current generation, which can occur when the traction motor is either disconnected or connected to the battery pack, leading to potential damage to the inverter and battery pack.
Innovation Solution
The implementation of intelligent vehicle systems with control logic that manage the electrical connection of the traction motor to the battery pack based on real-time drive system conditions, including speed and system status, to prevent damage by disconnecting the motor when not in use and connecting it only when necessary to maintain system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traction motor is electrically disconnected from the battery pack during towing, then damage to the inverter and electrical system is prevented, but counter electromotive force (EMF) is induced that could damage the bulk capacitor
Solution Approach 1:
The system dynamically switches the electrical connection state of the traction motor based on real-time operating conditions. During towing operations, the controller monitors vehicle speed and motor rotation, automatically transitioning between connected and disconnected states to prevent both counter EMF damage and uncontrolled regenerative charging, making the electrical connection state adaptive rather than fixed
Solution Approach 2:
The control system continuously monitors vehicle speed, motor rotation status, and electrical system parameters during towing. Based on this feedback, the controller intelligently determines whether to maintain electrical connection or disconnection, adjusting the system state in real-time to prevent both types of damage while managing any induced EMF through active control
2Stability of the object's composition
If the traction motor is electrically connected to the battery pack during towing, then the electrical system remains stable, but uncontrolled regenerative charging occurs generating excessive heat and voltage that may damage the power inverter module and battery pack
Solution Approach 1:
The system extracts the problematic regenerative charging function from the normally connected motor-battery system during towing operations. By selectively disconnecting the electrical connection when towing is detected, the system removes the source of uncontrolled regenerative charging and heat generation, while maintaining connection during normal operation for electrical stability
Solution Approach 2:
The electrical connection state is made dynamic rather than static, automatically transitioning between connected and disconnected states based on whether the vehicle is being towed. This dynamic adjustment prevents excessive heat generation during towing while maintaining electrical system stability during normal operation
3Reliability
If the traction motor is disconnected during towing to prevent regenerative charging, then heat and voltage damage is avoided, but the system complexity increases requiring intelligent control logic to manage connection states
Solution Approach 1:
The control system automatically detects towing conditions through sensors monitoring vehicle speed, motor rotation, and electrical parameters. The system self-manages the electrical connection state without requiring manual intervention or complex external control, using embedded logic to determine when to connect or disconnect the motor from the battery pack
Solution Approach 2:
The system uses sensor feedback from the vehicle's electrical system and motion sensors to automatically determine towing conditions. Based on this feedback, the control logic intelligently manages the electrical connection state, reducing the need for complex external control while maintaining reliability
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 solution effectively mitigates damage to the powertrain and electrical components by managing motor operation during towing, preventing thermal runaways and uncontrolled regenerative charging, thus ensuring the safety and integrity of the vehicle's electrical system.
Implementation Method 1
transform DC power to alternating current (AC) electric power using pulse-width modulated control signals output from a powertrain control module (PCM)
Implementation Method 2
rotation of the road-contacting wheels may inadvertently drive the vehicle's traction motor(s). Driving a traction motor when the vehicle is towed and the motor is electrically disconnected from the battery pack may induce a counter electromotive force (EMF) that could potentially damage the HV system's bulk capacitor
Implementation Method 3
Driving a traction motor during vehicle towing when the motor is electrically connected to the battery pack may push the drive system into uncontrolled regenerative charging that generates unfettered heat and a large voltage supply across the HV electrical system
Data Source
AI summary
Presented are intelligent vehicles and control logic for provisioning comprehensive tow features, methods for manufacturing/operating such vehicles, and electric-drive vehicles with tow features for protecting the vehicle's powertrain and electrical components during towing. A method for controlling operation of an electric-drive vehicle includes a vehicle controller verifying initiation of a towing operation for the vehicle, and responsively determining if there is a drive system failure preventing the vehicle's traction motor from electrically connecting with its traction battery pack. If there is no drive system failure, the controller determines if the speed of the traction motor during towing exceeds a calibrated base speed; if so, the controller commands a power inverter to electrically connect the traction motor to the traction battery pack. If, however, the towed motor speed does not exceed the calibrated base speed, the controller responsively commands the power inverter to disconnect the traction motor from the battery pack.