Vehicle Drive Control Device Speed Reduction Strategy
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Solution Overview
Problem
Existing vehicle drive control systems face challenges in promptly reducing the rotational speed of a rotating electrical machine during abnormalities while minimizing electrical load and preventing prolonged evacuation travel disruptions.
Innovation Solution
A vehicle drive control device that includes an electronic control unit to manage the engagement states of first and second engagement devices, disconnecting the rotating electrical machine from drive power sources to reduce rotational speed by inertia and reconnecting when safe to use internal combustion engine power, thus minimizing electrical load and enabling safe vehicle movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If active short-circuit control is performed to reduce rotational speed during abnormality, then rotational speed is reduced, but electrical load on the inverter and rotating electrical machine increases
Solution Approach 1:
The patent divides the fail-safe control process into two distinct phases: first, active short-circuit control is applied to rapidly reduce rotational speed; second, once speed is reduced below a threshold, the engagement device is disengaged to eliminate electrical load. This segmentation allows the system to achieve both speed reduction and load suppression at different time points.
Solution Approach 2:
The patent performs preliminary speed reduction through active short-circuit control before disengaging the engagement device. By first reducing rotational speed to a low level, the system prepares the rotating electrical machine to safely withstand disconnection without generating excessive counter-electromotive force or electrical load, thus enabling subsequent load suppression.
2Use of energy by moving object
If the engagement device is disengaged to reduce electrical load, then electrical load is suppressed, but drive power transmission to wheels is interrupted affecting evacuation travel
Solution Approach 1:
The patent performs preliminary speed reduction through active short-circuit control before disengaging the engagement device. By first reducing rotational speed to a low level, the system prepares the rotating electrical machine to safely withstand disconnection without generating excessive counter-electromotive force, enabling subsequent load suppression while minimizing disruption time.
Solution Approach 2:
The patent rushes through the speed reduction phase as quickly as possible using active short-circuit control, then rapidly transitions to the disengagement phase. This rapid progression through the critical speed reduction stage minimizes the overall time that drive power transmission is interrupted, thereby reducing evacuation travel disruption.
3Use of energy by moving object
If shutdown control is performed when counter-electromotive force is large, then electrical load is reduced, but rotational speed cannot be promptly reduced
Solution Approach 1:
The patent segments the control strategy into two phases: active short-circuit control for rapid speed reduction, followed by disengagement for load suppression. This avoids the problem of shutdown control at high speeds where counter-electromotive force prevents effective shutdown while still achieving both speed reduction and load reduction goals.
Solution Approach 2:
The patent performs preliminary speed reduction through active short-circuit control before applying shutdown control or disengagement. By first reducing rotational speed to a level where counter-electromotive force is manageable, the system enables effective shutdown or disengagement that would not be possible at high speeds, thus achieving both speed reduction and electrical load reduction.
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 reduces rotational speed and electrical load on the rotating electrical machine drive system, minimizing the duration of evacuation travel disruptions and ensuring safe vehicle operation during abnormalities.
Implementation Method 1
counter-electromotive force that is generated by the rotating electrical machine rotated by the wheels and the internal combustion engine is suppressed
Data Source
AI summary
A vehicle drive control device that controls a vehicle drive device in which a first engagement device, a rotating electrical machine, and a second engagement device are provided in this order from an input side in a mechanical power transmission path connecting an input to an output, the input being drive-coupled to an internal combustion engine serving as a vehicle drive power source, and the output being drive-coupled to wheels, wherein each of the first engagement device and the second engagement device can be changed between an engaged state in which drive power is transmitted and a disengaged state in which drive power is not transmitted, the vehicle control device including an electronic control unit.