Virtual Co-Phase Power Supply Topology for Railway Neutral Sections
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Solution Overview
Problem
Current power supply systems for railway traction have poor reliability, particularly when dealing with neutral sections, leading to potential overvoltage and arcing issues that can damage equipment and pose safety risks as train speeds increase.
Innovation Solution
A virtual co-phase power supply system topology is introduced, featuring a step-down transformer connected to rectifiers and inverters in parallel, with an LC filter and energy storage units, allowing for independent unit replacement and differential capacity operation between the rectifier and inverter sides to ensure continuous and reliable power supply through the neutral section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional ground neutral section auto-passing methods using air circuit breakers or power electronic switches are employed, then the locomotive can pass the neutral section automatically, but a power supply dead zone is created resulting in poor reliability
Solution Approach 1:
The patent introduces an intermediary energy storage device (capacitor bank) that stores electrical energy and releases it during the neutral section transition. This mediator bridges the power gap between the two feeding sections, ensuring continuous power supply to the locomotive without creating a dead zone, thus resolving the reliability issue while maintaining automation
Solution Approach 2:
The energy storage device is pre-charged during normal operation before the neutral section transition occurs. This preliminary energy accumulation ensures that when the transition happens, power is already available immediately, preventing any interruption in the power supply to the locomotive
2Reliability
If back-to-back converters or multi-level cascaded power electronic devices are used to eliminate power dead zones, then power continuity is improved, but system capacity requirements increase significantly
Solution Approach 1:
The patent changes the operational parameters by using a capacitor-based energy storage system instead of high-capacity power electronic converters. The capacitor bank is charged to a specific voltage level during normal operation and then discharged during the transition, providing the necessary power bridge with much lower overall system capacity requirements compared to back-to-back converter systems
3Object-affected harmful factors
If manual neutral section passing is used to prevent overvoltage and arcing, then equipment safety is improved, but labor intensity increases and operational efficiency decreases
Solution Approach 1:
The system performs automatic detection and execution of the neutral section transition process. Sensors detect the locomotive's approach to the neutral section, and the control system automatically manages the switching and energy storage device operation, eliminating the need for manual driver intervention while maintaining equipment safety through controlled transition
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 solution enhances system reliability and reduces capacity requirements, enabling uninterrupted power supply and preventing equipment damage by allowing easy replacement of faulty units and optimizing power distribution across the rectifier and inverter sides.
Implementation Method 1
a primary winding of the step-down transformer TR1 is electrically connected to the second traction feeding section β2
Implementation Method 2
Each secondary winding of the step-down transformer TR1 is electrically connected to a rectifier separately
Implementation Method 3
The other end is electrically connected to a plurality of parallel inverter units
Implementation Method 4
An LC filter is provided on a DC bus between a rectifier unit and the inverter unit
Implementation Method 5
the LC filter is connected in parallel to an energy storage unit
Implementation Method 6
an output end of the inverter unit is electrically connected to a primary winding of a step-up transformer TR2
Data Source
AI summary
A virtual co-phase power supply system topology suitable for an electrical sectioning device at a sectioning and paralleling post (SP) includes a step-down transformer TR1. A primary winding of the step-down transformer TR1 is electrically connected to a traction feeding section β2 in a train from a traction feeding section β1 to the traction feeding section β2. Each secondary winding is electrically connected to one rectifier separately. DC buses output from the rectifiers are connected in parallel. The other end of the DC bus is electrically connected to a plurality of parallel inverter units. An LC filter is provided on a DC bus between a rectifier unit and the inverter unit, and the LC filter is connected in parallel to an energy storage unit. After filtering through the LC filter, an output end of the inverter unit is electrically connected to a primary winding of a step-up transformer TR2.