Electric Vehicle Acceleration Control via Torque Limiting
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Solution Overview
Problem
Electric vehicles experience high acceleration rates that increase safety concerns, are inefficient in power consumption, and uncomfortable for passengers due to uncontrolled acceleration.
Innovation Solution
A control system for electric vehicles that determines an acceleration limit based on the requested torque and controls the electric motor to deliver torque without exceeding this limit, using an inverter to manage the motor's operation and ensure smooth acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the controller sends a signal to the motor to increase speed when the driver presses the gas pedal, then the vehicle acceleration performance is improved, but safety concerns increase and power consumption becomes inefficient
Solution Approach 1:
The control system continuously monitors the actual acceleration of the vehicle and compares it with the desired acceleration. Based on this feedback, the controller adjusts the motor torque to maintain safe acceleration levels while still responding to driver input. The system uses feedback from acceleration sensors and motor current sensors to dynamically regulate power delivery.
Solution Approach 2:
The system dynamically changes the torque parameter delivered by the motor based on vehicle operating conditions. By adjusting the torque command signal to the motor controller, the system limits acceleration rates to safe levels while still providing responsive vehicle performance. The acceleration limit parameter is modified based on vehicle speed, load, and other operational factors.
2Speed
If the controller sends a signal to the motor to increase speed when the driver presses the gas pedal, then the vehicle acceleration performance is improved, but power consumption efficiency deteriorates
Solution Approach 1:
The control system optimizes power consumption by dynamically adjusting the torque parameter delivered to the motor. Instead of delivering maximum torque requested by the driver, the system modifies the torque command based on acceleration limits and vehicle operating conditions, reducing unnecessary energy consumption while maintaining acceptable acceleration performance.
Solution Approach 2:
The system uses feedback from power consumption sensors and motor efficiency maps to adjust torque delivery. By monitoring actual power usage and comparing it with optimal efficiency contours, the controller modulates motor current and voltage to achieve acceleration with minimal energy waste, particularly during transient acceleration events.
3Speed
If the controller sends a signal to the motor to increase speed when the driver presses the gas pedal, then the vehicle acceleration performance is improved, but passenger comfort deteriorates
Solution Approach 1:
The control system adjusts the torque parameter delivered to the motor to smooth out acceleration transitions. By limiting the rate of torque change and filtering abrupt torque commands, the system reduces jerky movements and vibrations that affect passenger comfort. The acceleration profile is shaped to provide smooth, gradual acceleration rather than suddenjolts.
Solution Approach 2:
The control system applies damping algorithms that anticipate and counteract abrupt acceleration changes before they reach the passengers. By pre-filtering torque commands and applying smooth transition curves during acceleration events, the system cushions the mechanical shocks and vibrations transmitted to the vehicle interior, maintaining passenger comfort during acceleration.
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
The solution effectively limits acceleration to enhance safety, reduce power consumption, and improve passenger comfort by actively managing torque delivery and damping driveline oscillations.
Implementation Method 1
an inverter operatively coupled to the control system and the electric motor. The inverter may be configured to control the electric motor based at least on (a) a signal indicative of the requested torque, and (b) a signal indicative of the acceleration limit
Implementation Method 2
an electric motor configured to provide fraction and a control system. The control system may be configured to receive a signal indicative of a requested torque and determine an acceleration limit based on the requested torque
Data Source
AI summary
An electric vehicle includes an electric motor configured to provide traction and a control system. The control system may be configured to receive a signal indicative of a requested torque and determine an acceleration limit based on the requested torque. The electric vehicle may also include an inverter operatively coupled to the control system and the electric motor. The inverter may be configured to control the electric motor based at least on (a) a signal indicative of the requested torque, and (b) a signal indicative of the acceleration limit.