Series Switch Assembly Fault Isolation via Redundant Modules
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Solution Overview
Problem
In high and intermediate voltage applications, the reliability of power switch modules is reduced when one module fails, causing increased voltage stress on the remaining modules, which can lead to subsequent failures.
Innovation Solution
A switch assembly with redundant power switch modules and a fault protection system that includes isolation units and detection units to isolate faulty modules, allowing healthy modules to continue operating by bypassing the faulty ones, ensuring full current continuity and preventing further failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If multiple switch modules are connected in series to provide high voltage, then the voltage capability is improved, but the system reliability deteriorates because one failure can cause cascading failures
Solution Approach 1:
The system divides the series-connected switch modules into independently controllable segments. Each switch module is equipped with its own detection unit and isolation unit, allowing individual monitoring and isolation. This segmentation enables the system to maintain high voltage capability through series connection while improving reliability by containing failures to individual segments rather than causing cascading failures across the entire system.
Solution Approach 2:
The patent introduces detection units and isolation units as intermediary components between the series-connected switch modules. The detection units monitor the status of each module, and the isolation units can disconnect faulty modules from the series string. These intermediaries enable the system to detect and isolate failures quickly, preventing the increased voltage stress from propagating to other modules and causing cascading failures.
2Reliability
If redundant switch modules are added to improve reliability, then the system can continue operating after a failure, but the device complexity increases
Solution Approach 1:
The detection units and isolation units serve multiple functions: they detect faults, isolate faulty modules, and enable continued operation of healthy modules. This multi-functionality allows the system to achieve redundancy and continued operation without adding separate dedicated components for each function, thereby limiting the increase in device complexity while maintaining improved reliability.
Solution Approach 2:
The system performs preliminary detection and isolation actions automatically when a fault is detected. The detection units continuously monitor switch module status, and upon detecting a failure, the isolation units immediately disconnect the faulty module. This preliminary action prevents the faulty module from affecting other modules, enabling the redundant modules to take over and maintain system operation without requiring complex manual intervention or system reconfiguration.
Data Source
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AI summary
A system, a switch assembly thereof and an associated method are provided. The system includes a number of switch assemblies (44). The switch assemblies each include a switch module (36), multiple isolation circuits (38), a detection unit and a drive unit (40). The switch module (36) includes a number of power switch devices (Q1, Q2, Q3) connected in parallel. The switch modules of the switch assemblies are connected in series. The isolation circuits (38) each are connected in series to a gate terminal of at least one corresponding power switch device of the power switch devices (Q1, Q2, Q3). Each isolation circuit (38) includes a capacitor (C1, C2, C3) or a controllable switch. The detection unit is for detecting a fault in at least one of the power switch devices (Q1, Q2, Q3). The drive unit (40) is coupled to the switch module (36) via the isolation circuits (38) for driving the power switch devices (Q1, Q2, Q3) of the corresponding switch module (36), and when the fault is detected, the drive unit (40) is for turning on the power switch devices parallel connected to the at least one of faulty power switch devices.