Traction Converter Synchronization via Electrical Line
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Solution Overview
Problem
Synchronizing pulse-width modulated electrical traction converters in electrical trains is challenging due to clock inaccuracies, leading to low-frequency disturbances in the grid, especially when converters are distant from each other, and existing solutions like fiber optics may not be robust or easy to install.
Innovation Solution
A synchronization system using an electrical line to transmit a synchronization signal between controllers, allowing for carrier signal synchronization, with a master controller generating a synchronization signal based on the timing of its carrier signal and slave controllers adjusting their carrier signals to minimize harmonics, and utilizing existing power lines to simplify installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber optics lines are used to synchronise controllers in different wagons, then synchronisation precision is improved, but system complexity and installation difficulty increase
Solution Approach 1:
The patent uses the existing electrical line as an intermediary carrier to transmit the synchronisation signal between controllers in different wagons. Instead of requiring dedicated fiber optics infrastructure, the electrical line serves as a dual-purpose medium for both power/control signals and synchronisation timing signals, thereby reducing system complexity while maintaining synchronisation precision.
Solution Approach 2:
The electrical line is utilized for multiple functions: transmitting control signals, power signals, and synchronisation signals simultaneously. This multi-functionality eliminates the need for separate fiber optics lines, reducing installation complexity and cost while achieving the required synchronisation accuracy across distributed converters.
2Measurement precision
If fiber optics lines are used to synchronise controllers in different wagons, then synchronisation precision is improved, but ease of installation deteriorates
Solution Approach 1:
The electrical line acts as an existing infrastructure intermediary that is already deployed throughout the train system. By leveraging this pre-installed infrastructure for synchronisation signal transmission, the patent eliminates the need for additional fiber optics installation, thereby dramatically improving ease of installation while maintaining synchronisation precision.
Solution Approach 2:
The electrical line infrastructure serves itself by carrying both its original functions and the additional synchronisation function. The existing physical infrastructure is repurposed to provide synchronisation services without requiring separate dedicated infrastructure, making the system easier to install and maintain.
3Adaptability or versatility
If carrier signals are not synchronised, then converter operation independence is improved, but grid disturbance increases
Solution Approach 1:
The master controller generates a synchronisation signal based on its carrier signal timing and transmits it to slave controllers via the electrical line. The slave controllers use this feedback signal to adjust their carrier signal phases, ensuring they remain synchronised with the master controller. This feedback mechanism eliminates low-frequency disturbances while preserving converter operation independence through the electrical line communication infrastructure.
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 simplifies the synchronization of traction converters, reduces grid disturbances, and is more robust and easier to install than fiber optics, ensuring efficient operation of electrical trains by minimizing harmonics and compensating for signal delays.
Implementation Method 1
an electrical line for transmitting a synchronization signal as electrical signal between the first controller and the second controller
Data Source
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AI summary
A synchronisation system (28) for at least two pulse-width modulated electrical traction converters (14a, 14d) comprises a first controller (18a) adapted for switching a first traction converter (14a) with pulse width modulation based on a first carrier signal (32a); a second controller (18d) adapted for switching a second traction converter (14d) with pulse width modulation based on a second carrier signal (32b); and an electrical line (22) for transmitting a synchronisation signal (24) as electrical signal between the first controller (18a) and the second controller (18d); wherein the first controller (18a) is adapted for generating the synchronisation signal (24) based on a timing of the first carrier signal (32a); wherein the second controller (18d) is adapted for determining a carrier shift of the second carrier signal (32b) with respect to the first carrier signal (32a) based on the synchronisation signal (24a).