Dynamic Speed Modulation for EV Regenerative Braking Control
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Solution Overview
Problem
Battery-powered electric vehicles face challenges in extended braking applications, particularly when the battery approaches full charge, leading to reduced motor regenerative torque and potential loss of control due to excessive energy storage, and existing solutions like braking resistors can exceed power capacity, posing safety and productivity issues.
Innovation Solution
A controller with software that monitors battery parameters and adjusts vehicle speed to prevent overcharging by limiting regenerative braking power, ensuring safe operation and maintaining full motor torque during governed running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used to charge the battery, then energy recovery is improved, but the battery may become overcharged when it approaches full capacity
Solution Approach 1:
The control system continuously monitors battery state of charge and dynamically adjusts regenerative braking torque based on feedback signals. When the battery approaches full charge, the system reduces or disables regenerative braking to prevent overcharging, while maintaining friction braking capability for speed control.
Solution Approach 2:
The system dynamically transitions between different braking modes (regenerative vs. friction) based on real-time battery conditions. The regenerative braking torque is not fixed but varies continuously according to battery state of charge, allowing optimal energy recovery while preventing overcharge.
2Reliability
If braking resistors are used to dissipate regenerative braking power, then battery overcharge is prevented, but the power capacity of the braking resistor may be exceeded
Solution Approach 1:
The control system acts as an intermediary between the regenerative braking system and the braking resistor, intelligently distributing braking torque. It prioritizes regenerative braking for energy recovery and only engages the braking resistor when necessary and within its power capacity, preventing both overcharge and overload conditions.
Solution Approach 2:
The system changes operational parameters by adjusting the split between regenerative braking and friction braking based on battery state of charge and braking resistor power capacity. This dynamic parameter adjustment ensures safe operation within system limits while maximizing energy recovery.
3Reliability
If regenerative braking torque is reduced to prevent battery overcharge, then battery safety is improved, but motor torque and vehicle control are reduced
Solution Approach 1:
The braking system is segmented into independent regenerative braking and friction braking components. When battery safety requires reduced regenerative torque, the friction braking component compensates to maintain total braking force, ensuring vehicle control is preserved while protecting the battery.
4Reliability
If friction brakes are used instead of regenerative braking, then battery overcharge is prevented, but friction material consumption increases
Solution Approach 1:
The system maintains continuous useful action by prioritizing regenerative braking for energy recovery and only switching to friction braking when battery conditions prevent charging. This minimizes friction material consumption while ensuring battery protection, as friction brakes are engaged only when necessary rather than continuously.
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 prevents power system damage from excessive regenerative braking, allowing safe and efficient operation even when batteries are near full charge, enhancing safety and productivity in applications like underground mining.
Implementation Method 1
a regenerative braking system operatively connected to the at least one electric motor which progressively limits the groundspeed of the vehicle and provides recharging power to the battery
Implementation Method 2
adjusting the current groundspeed of the vehicle between zero and a maximum operating groundspeed
Data Source
AI summary
A method of dynamic speed modulation in extended braking applications in a battery-powered electric vehicle is disclosed. The method includes determining a sensed parameter of the battery, and determining a parameter threshold of the battery. If the sensed parameter of the battery is the same or exceeds the parameter threshold, decreasing the groundspeed of the vehicle to a predetermined safe speed. If the sensed parameter of the battery is below the parameter threshold, determining the change in the parameter which would be caused by the regenerative braking system at the current groundspeed of the vehicle. If the change in the parameter would cause the sensed parameter to remain, reach or exceed the parameter threshold, correspondingly decreasing or increasing the groundspeed of the vehicle to cause the sensed parameter to approximate but not exceed the parameter threshold of the battery. A controller and electric vehicle capable of same, are also disclosed.