Cascade Converter Module Operation via Dynamic Bypass Switching
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Solution Overview
Problem
Cascade converter systems face limitations in reliability due to a limited number of redundant converter modules, leading to system failure when all redundant modules are bypassed and another converter module fails, resulting in an inability to synthesize a qualified waveform.
Innovation Solution
A method for operating a cascade converter system that includes n converter modules and n bypass switch modules, where the system controller controls the bypass switch modules to either bypass or not bypass converter modules, allowing for seamless addition of new converter modules by adjusting duty cycle signals and carrier phase shifting, ensuring continuous operation even when redundant modules fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant converter modules are added to improve system reliability, then the system can tolerate more faults, but the device complexity and cost increase
Solution Approach 1:
The patent implements dynamic reconfiguration of converter modules during operation. When a fault occurs, the system dynamically switches from a fixed topology to an alternative topology by changing the connection state of converter modules, allowing the system to adapt to different fault conditions and maintain operation without requiring permanent redundant hardware for all possible failure scenarios.
Solution Approach 2:
The patent makes converter modules multi-functional by enabling them to serve both as operational modules and as backup modules depending on system needs. The same physical modules can be reconfigured to provide different functions (normal operation vs. fault tolerance) through topology switching, eliminating the need for dedicated redundant modules for each possible failure mode.
2Reliability
If the number of converter modules is increased to maintain waveform synthesis capability after faults, then system reliability improves, but the ease of operation and control complexity worsen
Solution Approach 1:
The patent changes the topological parameters of the converter system by switching between different connection configurations (series-parallel arrangements). This allows the system to maintain waveform synthesis capability with different numbers of active modules by adjusting the topology, rather than requiring a fixed large number of modules to handle all fault scenarios.
3Device complexity
If converter modules are operated in fixed configuration, then control is simpler, but the adaptability to fault conditions and operational flexibility deteriorate
Solution Approach 1:
The system transitions from static to dynamic operation by implementing real-time topology reconfiguration based on fault detection. The converter modules can dynamically change their operational state and connection configuration, allowing the system to adapt to various fault conditions while maintaining relatively simple control through automated switching logic.
Data Source
AI summary
A method of putting a converter module of a cascade converter system into operation, wherein the cascade converter system includes: n converter modules; n bypass switch modules; and a system controller, wherein the method includes: a module pre-plug-in step: m bypass switch modules of the n bypass switch modules being in a non-bypass state, and remaining n-m bypass switch modules being in a bypass state, the system controller communicating with the module controllers of the m converter modules, such that the m converter modules operate according to a first control signal, wherein 1≤m<n; a module plug-in step: the system controller controls the (m+1)th bypass switch module to change from the bypass state to the non-bypass state; and a module post-plug-in step: the system controller communicating with the module controllers of the m+1 converter modules, such that the m+1 converter modules operate according to a second control signal.