Electric Vehicle Torque Control for Gearshift G-Force
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Solution Overview
Problem
Electric vehicles with rotary electric machines do not provide a significant change in acceleration g-force when shifting gears, similar to conventional power plants, leading to user dissatisfaction.
Innovation Solution
An electric vehicle system that includes a motor, DC voltage generator, inverter, transmission, user operation unit, and controller, where the controller adjusts the DC or AC voltage command values based on gearshift position and speed control to increase acceleration g-force by setting the voltage higher than the operation-based value during gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the output torque of the rotary electric machine is kept substantially constant regardless of gear ratio, then the control is simplified and the engine rotation is stabilized, but the user cannot experience a change in acceleration g-force corresponding to the gearshift
Solution Approach 1:
The patent applies dynamics by making the control strategy adaptive rather than static. The controller dynamically switches between two different control modes: constant output torque control during normal operation, and accelerated output torque control during gearshift transitions. This dynamic adaptation allows the system to maintain engine rotation stability during cruising while providing noticeable acceleration g-force changes during gearshifts, thereby resolving the contradiction between stability and user experience.
Solution Approach 2:
The patent changes the control parameter from a fixed constant output torque to a variable torque that depends on the gearshift state. By detecting gearshift position changes and temporarily increasing the output torque command value during downshifts, the system creates a noticeable acceleration g-force change that mimics conventional power plants, while returning to constant torque control after the gearshift completes, thus maintaining overall stability.
2Productivity
If the DC voltage command value or AC voltage command value is set to an operation-based value corresponding to gearshift position and speed control amount, then the motor control is optimized for normal operation, but the acceleration g-force change during gearshift is insufficient
Solution Approach 1:
The patent applies preliminary action by detecting the gearshift position change in advance and proactively increasing the output torque command value before the gearshift fully completes. This anticipatory torque increase ensures that the acceleration g-force change is noticeable to the user during the transition, while the controller returns to normal operation-based control after the gearshift, thus maintaining both control efficiency and user experience.
3Ease of operation
If a conventional power plant is used, then the user can experience a change in acceleration g-force during gearshift, but the system complexity increases compared to an electric motor system
Solution Approach 1:
The patent replaces the complex mechanical system of a conventional power plant with an electric motor system that uses electronic control to achieve the same user experience. By using the controller to dynamically adjust the output torque command value based on gearshift detection, the system replicates the acceleration g-force changes of conventional vehicles without the mechanical complexity of engines and transmissions, thus resolving the contradiction between user experience and system complexity.
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
Enables users to experience a change in acceleration g-force similar to conventional power plants, enhancing the driving experience by increasing torque and acceleration during gear shifts.
Implementation Method 1
a DC voltage generator that generates a DC voltage based on a DC voltage command value to be supplied
Implementation Method 2
an inverter that converts the DC voltage into an AC voltage based on an AC voltage command value to be supplied, and applies the AC voltage to the motor
Implementation Method 3
a motor; a wheel; ... applies the AC voltage to the motor
Implementation Method 4
a transmission that sets a gearshift position based on a gearshift position command value to be supplied, and reduces a rotation speed of the motor with a gear ratio based on the gearshift position to rotationally drive the wheel
Data Source
AI summary
An electric vehicle allows a user to experience changes in acceleration g-force, as with a conventional power plant, including: a transmission that sets a gearshift position based on a gearshift position command value to be supplied, and reduces a rotation speed of a motor with the gear ratio based on the gearshift position to rotationally drive wheels; a user operation unit that outputs the gearshift position command value and a speed control amount, based on user operation; and a controller that sets a DC voltage command value or an AC voltage command value to an operation-based value corresponding to the gearshift position and the speed control amount, and, on the condition that operation on the user operation unit satisfies a predetermined condition, sets the DC voltage command value or the AC voltage command value to a value higher than the operation-based value for causing a change in acceleration.