Pyrotechnic Bypass Switch for Modular Power Converter Submodules
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Solution Overview
Problem
Modular multilevel power converters face operational disruptions and efficiency losses due to faults in submodules, particularly in difficult-to-maintain applications like offshore wind turbines or ships, where existing bypass solutions require external power supply and are prone to corrosion, leading to significant maintenance challenges and potential permanent damage.
Innovation Solution
A submodule with a bypass switch using a pyrotechnic force element to immediately short-circuit faulty submodules at their input terminals, eliminating the need for constant control and holding power, and featuring a vacuum interrupter for corrosion protection and reliability, along with redundant ignition circuits and control channels for enhanced safety and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnetic short-circuit switch is used to bridge faulty submodules, then the converter can continue operating, but the system requires external power supply and the switch is prone to corrosion
Solution Approach 1:
The pyrotechnic force element is ignited by a control signal from the control device to generate gas pressure that actuates the bypass switch. The system uses its own control signals and generated gas pressure rather than external power supply, making the subsystem self-sufficient and eliminating the need for external power connections to the bypass mechanism.
Solution Approach 2:
The patent replaces the electromagnetic short-circuit switch with a pyrotechnic-actuated bypass switch. Instead of using electromagnetic fields to operate the switch, a pyrotechnic force element generates gas pressure that mechanically actuates the bypass switch, substituting an electromagnetic system with a pyrotechnic-mechanical system that is more reliable in harsh environments.
2Reliability
If an electromagnetic short-circuit switch is used for bypassing, then fault tolerance is achieved, but maintenance effort increases due to corrosion
Solution Approach 1:
The bypass switch is actuated by gas pressure from a pyrotechnic force element, creating a sealed, inert environment for the switching mechanism. This eliminates exposure to corrosive external environments, preventing corrosion of contacts and reducing maintenance requirements while maintaining fault tolerance capability.
3Reliability
If conventional bypass switches are used, then submodule faults can be bridged, but power losses occur and control complexity increases
Solution Approach 1:
The pyrotechnic force element is ignited on demand by a control signal only when a fault occurs, rather than requiring continuous power supply and control. This periodic, event-driven operation eliminates continuous power consumption and associated losses while maintaining the ability to bridge faulty submodules when needed.
4Use of energy by stationary object
If external power supply is provided for short-circuit switches, then holding power is available, but system complexity and approval requirements increase
Solution Approach 1:
The bypass switch uses a pyrotechnic force element that is ignited by a control signal from the converter's existing control device. The system generates its own actuation energy through the pyrotechnic reaction rather than relying on external power supply infrastructure, simplifying the overall system while maintaining operational capability.
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
Enables seamless operation of power converters with minimal power losses and reduced maintenance efforts by permanently short-circuiting faulty submodules without requiring external power, improving reliability and safety through pyrotechnic force element and vacuum interrupter design, and simplifying integration and approval processes.
Implementation Method 1
A bypass switch (30) with a vacuum interrupter (32) and a pyrotechnic force element (34) are provided in each submodule (16i). The bypass switch (30) is designed in such a way that the pyrotechnic force element (34) can be ignited by a control signal from a control device (41) for actuating the bypass switch (30).
Implementation Method 2
A bypass switch (30) with a vacuum interrupter (32) are provided in each submodule (16i)
Data Source
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AI summary
The invention discloses a submodule (16a-16z) in particular for a modular multilevel power converter (1) which has a first input terminal (X1a-X1n) and a second input terminal (X2i-X2z) as well as a bypass switch (30), wherein the first input terminal (X1a-X1n) and the second input terminal (X2i-X2z) can be short-circuited by closing the bypass switch (30), and wherein the bypass switch (30) has a pyrotechnic force element (34) which is configured to close the switching path in the bypass switch (30) by ignition.