Generator Braking Torque Cycling for Stable Regenerative Braking
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Solution Overview
Problem
Existing electric drive systems for vehicles struggle to regulate generator braking moment effectively, particularly in varying road conditions and when reference speed is uncertain, leading to instability and inefficiency in braking.
Innovation Solution
A method for regulating the generator braking moment of an electric drive system, involving sensing a call for braking and adjusting the braking moment in cycles with sub-cycles, allowing for continuous modulation of the braking moment to adapt to changing road conditions and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If generator braking moment is regulated continuously without cycling, then braking efficiency is improved, but stability deteriorates under varying road conditions
Solution Approach 1:
The patent implements periodic cycling of the generator braking moment between increasing and decreasing phases. This periodic modulation prevents continuous regulation instability by systematically varying the braking moment in controlled cycles, thereby maintaining system stability while preserving overall braking efficiency through the structured alternation of braking intensity.
2Loss of energy
If generator braking moment is increased to improve recuperation, then energy recovery is improved, but wheel lock-up risk increases
Solution Approach 1:
The patent dynamically adjusts the generator braking moment through cyclic increasing and decreasing phases rather than maintaining a static high braking moment. This dynamic regulation allows the system to maximize energy recovery during the increasing phase while preventing wheel lock-up during the decreasing phase, thereby balancing energy recovery performance with wheel lock-up prevention.
Solution Approach 2:
The patent incorporates feedback mechanisms that monitor wheel slip and braking conditions to regulate the generator braking moment cyclically. This feedback-controlled cycling ensures that energy recovery is maximized when conditions permit while automatically reducing braking moment when wheel lock-up risk is detected, thus reconciling energy recovery with wheel lock-up prevention.
3Device complexity
If reference speed is used for braking regulation, then braking control is simplified, but accuracy deteriorates due to reference speed errors
Solution Approach 1:
The patent implements self-service regulation by using the cyclic modulation of generator braking moment to inherently compensate for reference speed errors. The systematic increasing and decreasing phases create self-correcting behavior that maintains accurate braking regulation without requiring complex external correction mechanisms, thereby preserving control simplicity while improving accuracy.
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 enables robust and efficient braking regulation, independent of reference speed errors, by maintaining a continuous braking moment that adapts to road conditions, improving stability and braking performance while allowing for effective recuperation.
Implementation Method 1
the electric drive being configured for regenerative braking... braking energy to be recovered in the form of electrical energy (recuperation)
Data Source
AI summary
A method is for regulating a generator braking moment of an electric drive for a vehicle, in particular a utility vehicle. The method includes: sensing a call for braking for the purpose of braking the vehicle using a setpoint braking moment; and, regulating the generator braking moment in dependence on the setpoint braking moment and on a trigger condition. The regulating is effected within a plurality of cycles. Within a cycle, changing of a generator braking moment provided by the electric drive is effected. Each of the cycles includes a first sub-cycle and a second sub-cycle. In the first sub-cycle, the changing includes reducing the generator braking moment and, in the second sub-cycle, the changing includes increasing the generator braking moment.