Hybrid EV Braking With Resistor Dissipation at Full Battery Charge
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Solution Overview
Problem
Electric vehicles face challenges in implementing regenerative braking when the battery is fully charged, as they resort to dissipative braking systems that are bulky, complex, and inefficient, and there is a need for a lighter, simpler dissipative braking system that can coexist with regenerative braking.
Innovation Solution
Incorporating a resistor device connected to the electric machine to convert excess kinetic braking energy into heat, allowing for a hybrid braking system that operates efficiently regardless of the battery's charge state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dissipative braking system is designed to handle full braking capacity, then reliable braking is ensured when battery is charged, but the system becomes bulky, complex and heavier
Solution Approach 1:
The braking system is segmented into two independent paths: a first dissipative braking device connected to the wheel for direct kinetic energy conversion, and a second dissipative braking device (resistor) connected to the electric machine for electrical energy conversion. This segmentation allows each component to be optimized for its specific function, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The patent merges regenerative braking and dissipative braking systems into a hybrid configuration where the electric machine serves dual purposes: as a motor during acceleration and as a generator during braking to charge the battery or power a resistor. This integration reduces the need for separate dedicated components, simplifying the overall system.
2Reliability
If a dissipative braking system is designed to handle full braking capacity, then reliable braking is ensured when battery is charged, but the system weight increases
Solution Approach 1:
The braking system is segmented into two independent paths: a first dissipative braking device connected to the wheel for direct kinetic energy conversion, and a second dissipative braking device (resistor) connected to the electric machine for electrical energy conversion. This segmentation allows each component to be optimized for its specific function, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The patent merges regenerative braking and dissipative braking systems into a hybrid configuration where the electric machine serves dual purposes: as a motor during acceleration and as a generator during braking to charge the battery or power a resistor. This integration reduces the need for separate dedicated components, simplifying the overall system.
3Use of energy by moving object
If regenerative braking is used to charge the battery, then energy efficiency is improved, but braking capability is lost when battery is fully charged
Solution Approach 1:
The resistor acts as an intermediary energy dissipation device. When the battery is fully charged and cannot accept more energy, the resistor provides an alternative path for converting kinetic energy into heat, ensuring continuous braking capability. It mediates between the regenerative braking system and the dissipative braking device, allowing seamless transition between different braking modes.
Solution Approach 2:
The system dynamically changes its energy management parameters based on battery state of charge. When the battery is not full, regenerative braking is activated to maximize energy recovery. When the battery reaches full charge, the system switches to using the resistor for energy dissipation, maintaining optimal braking performance throughout all operating conditions.
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 with a compact and simpler dissipative system that complements regenerative braking, maintaining optimal performance even when the battery is fully charged, and provides flexibility in energy dissipation strategies.
Implementation Method 1
a resistor device connected to the electric machine and configured to convert incoming electrical energy arriving from the electric machine into heat
Implementation Method 2
the kinetic braking energy is directly converted into frictional heat between the brake discs and pads
Implementation Method 3
an electric machine powered by a battery that converts incoming electrical energy into outgoing kinetic energy... 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
Data Source
AI summary
An electric-powered road 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 is 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 converts the kinetic braking energy of at least one of said wheels into heat. A resistor device is connected to the electric machine and is configured to convert incoming electrical energy arriving from the electric machine into heat.