EV Braking Resistor Path for Full-Battery Regenerative Braking
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Solution Overview
Problem
Existing electric vehicles face challenges in implementing regenerative braking when the battery is fully charged, as they resort to heavier, bulkier dissipative braking systems to manage excess kinetic energy, compromising braking efficiency and complexity.
Innovation Solution
Incorporating a resistor device connected to the electric machine to convert excess kinetic energy into heat, allowing for a lighter and simpler dissipative braking system that operates alongside regenerative braking, even when the battery is fully charged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a regenerative braking system is used in electric vehicles, then energy recovery efficiency is improved, but braking system complexity increases when battery is fully charged
Solution Approach 1:
The braking system is segmented into multiple independent components: regenerative braking mechanism, dissipative braking device, and resistor device. Each component operates independently based on battery charge state, allowing the system to switch between energy recovery mode and heat dissipation mode without requiring complex integration logic.
Solution Approach 2:
The resistor device acts as an intermediary energy dissipation pathway between the electric machine and the environment. When the battery is fully charged, the resistor provides a direct route for converting kinetic energy to heat, eliminating the need for complex control systems to manage energy flow during braking.
2Reliability
If a dissipative braking system is designed to handle full braking capacity, then braking reliability is improved, but system weight increases
Solution Approach 1:
The braking function is divided between the dissipative braking device and the resistor device. The dissipative braking device only needs to handle partial braking capacity (when battery is fully charged), while the resistor handles the remaining energy dissipation. This segmentation allows each component to be optimized for its specific function, reducing overall system weight.
Solution Approach 2:
The dissipative braking device is designed with partial capacity rather than full braking capacity. By combining it with the resistor device that can handle excessive energy dissipation needs, the system achieves full braking reliability while keeping the dissipative device lighter and more compact.
3Weight of moving object
If a dissipative braking device is made lighter and more compact, then vehicle weight is reduced, but braking capacity is compromised
Solution Approach 1:
The system merges the dissipative braking device with the resistor device to create a hybrid braking system. The lighter dissipative braking device handles mechanical friction braking, while the resistor handles electrical energy dissipation. Together, they provide full braking capacity without requiring the dissipative device to be oversized.
Solution Approach 2:
The resistor device serves as an intermediary that supplements the lighter dissipative braking device. When the dissipative device's capacity is insufficient, the resistor steps in to handle the additional energy dissipation requirement, ensuring full braking capacity is maintained despite the reduced size of the mechanical braking components.
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 efficient braking by converting kinetic energy into electrical energy for battery charging or heat dissipation, maintaining braking performance and reducing system complexity and weight.
Implementation Method 1
at least one electric machine configured to convert electrical energy into kinetic energy (and vice versa); wherein the electric machine is connected, on one side, to the at least one battery and, on another side, to at least one of said wheels in such a way that during the vehicle's running or acceleration the electric machine converts incoming electrical energy arriving from the battery into kinetic energy to be transmitted to at least one of said wheels
Implementation Method 2
an electric machine of these vehicles is also able to run in the opposite direction in order to utilise the incoming kinetic braking energy into current output to the battery
Implementation Method 3
during braking, kinetic energy is dissipated for these types of cars by conversion into heat through friction between brake pads and brake discs
Implementation Method 4
a resistor device connected to the electric machine and configured to convert incoming electrical energy arriving from the electric machine into heat
Data Source
Figure 1~2
Figure 3~6
Figure 7~8
AI summary
An electric-powered road vehicle; wherein the vehicle comprises two front wheels and two rear wheels; at least one battery; at least one electric machine configured to convert electrical energy to kinetic energy and vice versa; the electric machine being connected, on one side, to at least one battery and, on another side, to at least one of said wheels in such a way that during the running or acceleration of the vehicle the electric machine converts incoming electrical energy arriving from the battery into kinetic energy to be transmitted to at least one of said wheels; at least one dissipative braking device to convert the kinetic braking energy of at least one of said wheels into heat; the vehicle also comprises a resistor device connected to the electric machine and configured to convert incoming electrical energy arriving from the electric machine into heat; with the battery in a fully charged state or part of the kinetic braking energy from at least one of said wheels is converted by the electric machine into electrical energy transmitted to the resistor device and there converted into heat.