DC Link Voltage Stabilization via Active Damping Control
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Solution Overview
Problem
Existing systems for feeding electric power to consumers, particularly in track-bound vehicles, face instability due to poorly damped input filters and interference between power control objectives and stabilization methods, leading to potential system shutdowns and inefficiencies.
Innovation Solution
A system that includes a control unit to sense parameters and dynamically adjust between using a converter to add a first power component for stabilization and a second consumer, such as a brake chopper, to consume a second power component, allowing for efficient voltage stabilization without additional power losses or system overdimensioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If passive damping components (additional or larger filters) are added to stabilize the DC link voltage, then system stability is improved, but device complexity, cost, weight, space, and total power losses increase
Solution Approach 1:
The patent replaces passive mechanical damping components (filters) with an active control system. The converter control unit is configured to provide active damping by modifying the control signal to the converter, which compensates for the poorly damped input filter without adding physical damping components. This substitution of active control for passive components resolves the contradiction by improving stability while avoiding increased device complexity, cost, weight, and power losses.
2Stability of the object's composition
If the converter control is modified to add a first power component for stabilization, then system stability is improved, but internal high-priority power-control objectives (current, torque, power limitations, performance objectives) may be interfered with
Solution Approach 1:
The patent implements a dynamic control strategy where the active damping is adjusted based on system conditions. The converter control unit modifies the control signal dynamically, and the system can switch between different stabilization approaches (converter-based active damping or second consumer-based damping) depending on whether converter control objectives can be met. This dynamic adaptability resolves the contradiction by providing stability while maintaining flexibility to fulfill internal control objectives when possible.
Solution Approach 2:
The patent changes the control parameters of the converter dynamically. An arrangement senses parameters indicating whether the converter can provide stabilization without interfering with its primary control objectives. Based on these parameter changes, the system adjusts the stabilization approach, switching to a second consumer (such as a brake chopper) when converter control objectives take priority. This parameter-based decision-making resolves the contradiction between stability and control objective fulfillment.
3Stability of the object's composition
If a second consumer (such as a brake chopper) is used to consume a second power component for stabilization, then system stability is improved and converter control objectives are maintained, but power losses increase due to the second consumer
Solution Approach 1:
The patent implements a self-service stabilization system where the second consumer (brake chopper) is used only when necessary, and the system preferentially uses the converter's own control capabilities for stabilization. The arrangement senses whether converter-based stabilization is possible, and only activates the second consumer when converter control objectives cannot be met. This selective self-service approach resolves the contradiction by minimizing reliance on the lossy second consumer while maintaining stability.
Solution Approach 2:
The patent applies partial action by using the second consumer only to the extent necessary for stabilization. Rather than continuously operating the second consumer, the system activates it partially or intermittently based on sensed parameters indicating converter control capability. This partial use of the second consumer provides necessary stabilization while minimizing power losses, resolving the contradiction between stability and energy efficiency.
Data Source
AI summary
A system for feeding electric power to a first consumer (1) comprises an input filter (6) with an input configured to be connected to a DC energy source and a DC intermediate link (3) connected to an output (14) of the input filter. A converter (12) is with an input connected to the DC intermediate link and has an output to be connected to said first consumer (1). The unit (16) controls the converter to obtain feeding of electric power requested by the first consumer independently of variations of the voltage on the DC link (3). An assembly is configured to act stabilizing on that voltage by controlling the converter to add a first power component to the power to be fed to the consumer. A second consumer (19) is controlled to consume a second power component to either assist the control of the converter to obtain the stabilization or alone take care thereof.