Electric Vehicle Control Device Regenerative Brake Torque Optimization
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Solution Overview
Problem
Conventional electric vehicle control devices require additional chopper devices and control systems to increase regenerative brake operation range, leading to increased device size.
Innovation Solution
An electric vehicle control device with an inverter, a calculation unit that determines and corrects regenerative-brake-torque load factors based on vehicle speed and element temperature, allowing for enhanced regenerative brake operation without additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a chopper device and chopper control device are added to increase regenerative brake operation range in high-speed range, then the regenerative brake operation range is improved, but the device size is enlarged
Solution Approach 1:
The patent changes the control parameters by determining regenerative-brake-torque load factors based on vehicle speed information and correcting them using element temperature information. This allows the system to operate efficiently across a wider speed range without adding hardware, resolving the contradiction by achieving adaptability through software-based parameter optimization rather than hardware expansion
Solution Approach 2:
The patent replaces the need for mechanical chopper devices with a control system that uses calculation units to determine and correct torque load factors. This substitution of physical hardware with computational control achieves the same functional goal of expanding operational range while avoiding the volume increase that would result from adding chopper devices
2Use of energy by moving object
If regenerative brake operation is increased in high-speed range, then energy recovery is improved, but switching element temperature may exceed permissible temperature
Solution Approach 1:
The patent implements feedback control by continuously monitoring element temperature information and using it to correct the regenerative-brake-torque load factors. When temperature approaches permissible limits, the system automatically adjusts the torque load factor to reduce stress on the switching elements, thereby maintaining energy recovery efficiency while preventing overheating
Solution Approach 2:
The patent makes the regenerative-brake-torque load factor dynamic by adjusting it based on real-time element temperature conditions. The correction unit modifies the torque load factor according to temperature variations, allowing the system to optimize energy recovery at different operating conditions while dynamically managing thermal constraints on the switching elements
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 increased regenerative brake operation range in high-speed conditions, reducing the need for additional devices, conserving power, and extending brake shoe life by optimizing regenerative brake usage and preventing excessive element temperatures.
Implementation Method 1
an inverter that drives a motor
Implementation Method 2
regenerative-brake-torque load factor when a braking command is detected
Data Source
AI summary
An electric vehicle control device includes a calculation unit that calculates a regenerative-brake-torque load factor when a braking command is detected. The calculation unit includes a brake-torque load-factor determination unit that determines the regenerative-brake-torque load factor according to vehicle speed information that is a detection value of vehicle speed; and a brake-torque load-factor correction unit that corrects the regenerative-brake-torque load factor determined by the brake-torque load-factor determination unit using element temperature information that is temperature information of a switching element included in an inverter.