Rail Vehicle DC Link Braking Without Grid Energy Feedback
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Solution Overview
Problem
Existing methods for vehicle braking in railway systems fail to allow electrodynamic braking in sections where energy recuperation into the trackside power supply network is prohibited, leading to inefficiencies and increased wear on friction brakes.
Innovation Solution
A method where the vehicle operates as an electrodynamic brake, feeding electrical braking energy into a DC intermediate circuit, and directs this energy to a vehicle-side load, blocking feedback into the power supply network, with load current regulation to maintain DC link voltage and using converters to manage energy flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If energy recuperation into the trackside power supply network is prohibited in a section, then electrodynamic braking cannot be performed according to conventional methods, but this leads to increased wear on friction brakes and reduced braking efficiency
Solution Approach 1:
The patent introduces a vehicle-side load (energy storage device or consumer) as an intermediary to absorb braking energy that cannot be fed back to the network. This mediator enables electrodynamic braking to function in prohibited sections by providing an alternative energy sink, thereby maintaining braking efficiency without requiring friction brakes.
Solution Approach 2:
The patent extracts the energy feedback path from the conventional braking system and replaces it with a vehicle-side load. By taking out the prohibited energy feedback connection and substituting it with a local energy absorption mechanism, the system maintains electrodynamic braking capability while adapting to network prohibitions.
2Loss of energy
If electrodynamic braking is deactivated in prohibited sections to prevent energy injection into the DC link, then energy recuperation is prevented, but braking efficiency is reduced and friction brakes must be used
Solution Approach 1:
The vehicle-side load acts as an intermediary energy sink that captures braking energy which would otherwise be lost or require friction braking. This enables continuous electrodynamic braking operation across all track sections, maximizing energy recovery utilization while simplifying control logic by maintaining a consistent braking mode.
Solution Approach 2:
The braking system is designed to universally handle both permitted and prohibited network sections using the same electrodynamic braking mechanism. The system adapts its energy destination (network or vehicle-side load) based on section type, eliminating the need for separate braking systems or complex mode switching.
3Ease of operation
If the DC link voltage is allowed to fluctuate during braking, then energy management is simpler, but this can cause instability in the power supply network and affect vehicle operation
Solution Approach 1:
The patent implements feedback control by monitoring DC link voltage and adjusting the load current accordingly. When voltage rises during braking, the control system increases the current drawn by the vehicle-side load to maintain voltage within acceptable ranges, ensuring power supply stability while managing braking energy.
Solution Approach 2:
The system dynamically changes the load current parameter based on DC link voltage conditions. By adjusting the current drawn by the vehicle-side load in response to voltage fluctuations, the system maintains electrical stability during electrodynamic braking without requiring complex energy management interventions.
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 electrodynamic braking in prohibited sections, reduces friction brake wear, and maintains DC link voltage stability, allowing energy to be stored or converted, thus optimizing braking efficiency.
Implementation Method 1
the vehicle's drive system operates as an electrodynamic brake, and the drive's electrical braking energy is fed into a DC link
Implementation Method 2
energy is extracted from the DC intermediate circuit by feeding a load current into a vehicle-side load, which absorbs the braking energy, for example, by converting it into heat
Data Source
Figure 1
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Figure 4
AI summary
The invention relates, inter alia, to a method for operating a vehicle (10) connected to a trackside power supply network (30). According to the invention, during braking within a track section with impermissible energy feedback into the power supply network (30), a drive (70) of the vehicle (10) is operated as an electrodynamic brake, and electrical braking energy from the drive (70) is fed into a DC link (60) of the vehicle. Energy is extracted from the DC link (60) by feeding a load current (Iload) into a vehicle-side load (90, 300, 310), and energy feedback from the DC link (60) into the power supply network (30) is blocked.