Two-Stage Power Module Switch-Fault Control With DC Midpoint Balance
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Solution Overview
Problem
Conventional fault-tolerant control methods for solid-state transformers either reduce power output or increase complexity and cost due to the need for redundant components, failing to adequately address switch failures in power electronic circuits.
Innovation Solution
A coordinated fault-tolerant control method for two-stage power modules that disables the faulty switch and operates complementary switches to maintain normal operation without adding redundant components, ensuring balanced DC midpoint voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant components are arranged to achieve fault-tolerant operation, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The power module is divided into multiple independent bridge arms, each with its own switches. When a switch fails, only the affected bridge arm is impacted while other segments continue operating, enabling fault isolation without requiring system-level redundancy
Solution Approach 2:
The system uses its existing switches and circuitry to compensate for failures. Healthy switches in the same or opposite bridge arms are reconfigured to replace the function of failed switches, allowing the system to serve itself during fault conditions without external redundant components
2Reliability
If the whole power module is bypassed when one switch fails, then reliability is improved, but power output is reduced
Solution Approach 1:
The power module is divided into multiple independent bridge arms, each with its own switches. When a switch fails, only the affected bridge arm is impacted while other segments continue operating, enabling fault isolation without requiring system-level redundancy
Solution Approach 2:
Instead of completely bypassing the power module when a switch fails, the system maintains partial operation by keeping healthy bridge arms functional. This partial action approach allows the system to continue delivering reduced but still significant power output rather than complete shutdown
3Reliability
If conventional fault-tolerant control methods are used, then switch failure is addressed, but system downtime increases
Solution Approach 1:
The control method is prepared in advance to handle switch failures. When a failure occurs, the pre-planned reconfiguration of switches and bridge arms can be executed immediately without requiring complex real-time decision-making or external intervention, minimizing system downtime
Solution Approach 2:
The system continuously monitors switch status and provides feedback to the control circuit. When a switch failure is detected, the feedback triggers automatic reconfiguration of the power module, enabling rapid response and minimizing the time the system spends in a degraded state
Data Source
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Figure 2B
AI summary
A coordinated fault-tolerant control method for a two-stage power module (1) is provided. The two-stage power module (1) includes a front-stage circuit (2) and a rear-stage circuit (3). The front-stage circuit (2) has a DC midpoint (Ce). Each of a first side circuit and a second side circuit of the rear-stage circuit (3) includes two rear-stage switch sets (30, 31, 32, 33). If one switch (S1, S2, S3, S4, S5, S6, S7, S8) in one of the two rear-stage switch sets (30, 31, 32, 33) in the first side circuit fails, disable the other switch (S1, S2, S3, S4, S5, S6, S7, S8) in the rear-stage switch set (30, 31, 32, 33). Operate the other rear-stage switch set (30, 31, 32, 33) in the first side circuit normally. One of the two rear-stage switch sets (30, 31, 32, 33) in the second side circuit is operated normally, and the other of the two rear-stage switch sets (30, 31, 32, 33) in the second side circuit is disabled.