Recuperative Brake Zero Slip Mode Battery Overcharge
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Solution Overview
Problem
Existing vehicle brake systems with recuperative support face challenges in maintaining constant and reliable braking performance when the traction battery is fully charged, leading to a need for methods that prevent overcharging and ensure continuous recuperation-based braking.
Innovation Solution
A method involving the operation of a second electric machine in a zero slip mode to decrease electrical energy generated during braking, either by transferring it to the traction battery or using it as a buffer storage, preventing overcharging and ensuring continuous recuperation-based braking by synchronizing the stator's rotary field with the rotor's movement without generating torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electrical energy is continuously generated during braking and transferred to the traction battery, then the energy recovery efficiency is improved, but the battery becomes overcharged when reaching full capacity
Solution Approach 1:
A buffer storage device is introduced as an intermediary between the first electric machine (energy generator) and the traction battery. This buffer temporarily stores generated electrical energy when the battery is fully charged, preventing overcharging while maintaining continuous recuperation capability. The buffer acts as a mediator that decouples the energy generation from energy storage, resolving the contradiction between energy recovery and battery protection.
Solution Approach 2:
The system performs preliminary actions by charging the buffer storage before transferring energy to the main traction battery. When the battery reaches full capacity, the system preemptively redirects excess energy to the buffer, preventing overcharging conditions. This preliminary energy redirection ensures the braking system remains reliable and can continue recovering energy without interruption.
2Weight of moving object
If the friction brake system is made lighter by relying on recuperation, then the vehicle efficiency is improved, but the braking system reliability deteriorates when the battery is fully charged
Solution Approach 1:
The buffer storage serves as a mediator that ensures continuous operability of the recuperation-based braking system. By providing a temporary energy reservoir, it guarantees that the electric machine can always generate braking torque regardless of the main battery's charge state, thus maintaining reliability while allowing the use of lighter friction brakes.
Solution Approach 2:
The system changes the operational parameters of the braking system by introducing a dual-storage architecture. The buffer storage allows the system to operate in different modes: direct charging of the main battery when capacity is available, and buffer charging when the main battery is full. This parameter flexibility ensures reliable braking performance across all battery states while maintaining reduced brake system weight.
3Quantity of substance
If the second electric machine operates in zero slip mode to decrease generated electrical energy, then the buffer storage is effectively utilized, but energy losses increase
Solution Approach 1:
The second electric machine operates in zero slip mode only partially - specifically when the buffer storage is full and needs to be discharged. This partial operation allows the system to utilize the buffer storage effectively without continuously incurring energy losses. The zero slip mode is activated only when necessary to maintain buffer utilization, balancing storage management with energy efficiency.
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
This approach allows for constant and reliable recuperation-based braking, enabling the use of lighter and more dynamic brake systems by preventing overcharging and providing a temporary storage for electrical energy, ensuring the vehicle can maintain deceleration through recuperation even when the battery is fully charged.
Implementation Method 1
operating with the electrical energy generated by the first electric machine a second electric machine in a zero slip mode in which a rotary field of a stator of the second electric machine synchronously follows a movement of a rotor of the second electric machine
Data Source
AI summary
The present invention relates to a method for recuperation based braking of a vehicle in which electrical energy generated during a braking process is decreased by operating at least one second electric machine of the vehicle in a zero slip mode in order to prevent overcharging of a traction battery of the vehicle.