MVDC Railway Converter Station Simulation With SRDAB Voltage Control
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Solution Overview
Problem
The existing railway converter stations linked to AC systems face challenges in expanding distribution line capacity due to public complaints and technical limitations, necessitating the transition to a Medium-Voltage Direct Current (MVDC) system for improved voltage expansion and current capacity.
Innovation Solution
A railway converter station linked to an MVDC distribution system, incorporating a series-resonant Dual Active Bridge (SRDAB) converter and a simulation system that includes a computing device, a Hardware In the Loop Simulation (HILS) device, and a converter controller to simulate and control the converter station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If AC system is used for distribution, then existing infrastructure can be maintained, but distribution line capacity cannot be expanded due to public complaints and technical limitations
Solution Approach 1:
The patent transitions from AC distribution to DC distribution, changing the fundamental electrical parameter from alternating current to direct current. This enables higher voltage levels (up to 45 kV DC) and increased current capacity without requiring physical expansion of distribution lines, thereby resolving the capacity expansion limitation while maintaining infrastructure compatibility.
2Quantity of substance
If DC/DC converter-based MVDC system is implemented, then voltage expansion and current capacity are improved, but converter station complexity increases
Solution Approach 1:
The converter station is segmented into modular functional units including rectifier transformers, DC/DC converters, and control systems. Each module performs a specific function and can be independently configured and maintained, reducing overall system complexity while achieving high voltage expansion and current capacity.
Solution Approach 2:
The DC/DC converter acts as an intermediary device between the MVDC distribution system and the railway traction system. It mediates voltage transformation and power flow control, enabling the system to achieve high current capacity while managing complexity through standardized intermediate conversion stages.
3Measurement precision
If conventional batch processing simulation is used, then computational accuracy is maintained, but real-time simulation performance is insufficient for virtual operation verification
Solution Approach 1:
The simulation system performs preliminary calculations and pre-computes train operation patterns, load profiles, and network parameters before real-time simulation execution. This preprocessing enables the main simulation loop to operate in real-time with high computational speed while maintaining accuracy through pre-established mathematical models and parameter sets.
Solution Approach 2:
The patent replaces conventional batch processing computational methods with a real-time simulation engine that uses optimized numerical algorithms and hardware acceleration. This substitution enables the simulation to achieve both high computational speed for real-time performance and maintained accuracy through sophisticated mathematical modeling of the MVDC railway system.
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 proposed solution enables efficient active voltage control, reduces the number of active and passive components, and allows for real-time simulation and optimization of the railway system without the need for field tests, thereby enhancing operational flexibility and safety.
Implementation Method 1
series-resonant Dual Active Bridge (SRDAB) converter
Data Source
AI summary
A simulation system of a railway system for a Medium-Voltage Direct Current (MVDC) distribution network includes: a computing device which stores a simulation program including a converter station model configured to simulate a converter station included in the MVDC distribution network and a train operation model configured to simulate an operation state of a train that is supplied with power from the converter station and runs; a converter controller which controls a DC/DC converter included in the converter station model; and a Hardware In the Loop Simulation (HILS) device which performs a simulation based on the converter station model, the train operation model, and the converter controller. Herein, the converter station model and the train operation model are executed in software by the HILS device, and the converter controller is connected to the HILS device and driven to control the converter station model.