Phase Module Arrester for Converter Overvoltage Protection
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Solution Overview
Problem
Converter arrangements face potential shifts due to grid faults, leading to overcharging of energy stores in switching modules, which can result in damage or failure, and existing solutions like increasing the number of switching modules are costly.
Innovation Solution
A phase module arrester is introduced in parallel to the series connections of switching modules for overvoltage protection, along with arm inductances and additional arresters, to limit charging and protect against potential shifts, eliminating the need for increased switching modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of switching modules in each converter arm is increased to protect against overcharging, then the reliability of the converter arrangement is improved, but the cost of the converter system increases
Solution Approach 1:
A phase module arrester is introduced as an intermediary protective device in parallel to the series connections of switching modules. This arrester acts as a mediator that limits overvoltage and prevents overcharging of energy stores, thereby protecting the switching modules without requiring additional switching modules in the converter arms.
2Reliability
If the number of switching modules is increased to address potential shift protection, then the reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The phase module arrester serves as a protective intermediary that directly addresses potential shift issues by limiting voltage during grid faults. This approach protects against potential shift without modifying the fundamental converter arm structure or increasing the number of switching modules.
Solution Approach 2:
The invention replaces expensive and complex switching module multiplication with a simpler, more economical protective device (phase module arrester) that can be added in parallel. The arrester is a dedicated protective component that handles fault conditions without requiring permanent structural changes to the converter arms.
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 phase module arrester effectively protects switching modules from overcharging during faults, ensuring reliable operation without the cost increase associated with more switching modules, and is suitable for high-voltage applications.
Implementation Method 1
a phase module arrester (15) in an arrester branch (16) parallel to the two series connections (13a, 13b) for overvoltage protection of the switching modules (13) of the two series connections (13a, 13b)
Data Source
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AI summary
The invention relates to a converter arrangement (1) having a converter phase (2), which extends between a first and a second DC voltage pole (3, 4), wherein the converter phase comprises an AC voltage terminal (10) and a first converter arm (7), which extends between the first DC voltage pole and the AC voltage terminal, and a second converter arm (8), which extends between the AC voltage terminal and the second DC voltage pole, wherein the first converter arm comprises a first series circuit (13a) of two-pole switching modules (13) and the second converter arm comprises a second series circuit (13b) of two-pole switching modules, wherein each of the switching modules comprises power semiconductor switches and an energy store. The invention is characterized by a phase module arrester (15) in an arrester branch (16) in parallel with the two series circuits of the switching modules, which phase module arrester is configured for overvoltage protection of the switching modules of the two series circuits. The invention further relates to a method for the short-circuit protection of the converter arrangement according to the invention.