Fault-Tolerant Power Converter Using Zero-Voltage Phase Bypass
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Solution Overview
Problem
Conventional power converters require additional spare inverters and changeover switches to continue operation if a semiconductor switching element fails, leading to increased cost and size.
Innovation Solution
A power converter design that includes an inverter circuit and three single-phase bridge circuits connected in series, with a power conversion controller that sets the output voltage of a faulty phase to zero when a semiconductor switching element fails, allowing continued operation without a spare inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spare inverters and changeover switches are added to continue operation after failure, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The single-phase bridge circuit is designed to perform multiple functions: normally it processes power in series with the inverter circuit, but when a semiconductor switching element fails, it can be reconfigured to bypass the faulty element while maintaining power conversion capability. This multi-functionality eliminates the need for separate spare inverters and changeover switches.
Solution Approach 2:
The circuit configuration dynamically changes based on operational conditions. Under normal conditions, the single-phase bridge circuit operates in series mode. When failure is detected, the circuit topology dynamically reconfigures to bypass the faulty semiconductor switching element, allowing continued operation without manual intervention or additional switching components.
2Reliability
If spare inverters are added to continue operation after failure, then reliability is improved, but size increases
Solution Approach 1:
The bypass functionality is merged into the existing single-phase bridge circuit structure rather than being implemented as a separate spare inverter system. The same circuit components serve both normal power conversion and fault bypass functions, significantly reducing the overall converter size while maintaining fault tolerance.
3Reliability
If changeover switches are added to bypass faulty elements, then reliability is improved, but device complexity increases
Solution Approach 1:
The system automatically detects semiconductor switching element failures and self-reconfigures the circuit topology to bypass faulty elements without requiring external changeover switches or manual intervention. The control unit manages the bypass operation internally, eliminating the need for additional switching mechanisms.
Data Source
AI summary
A power converter includes an inverter circuit connected between the positive and negative terminals of a DC power supply, three single-phase bridge circuits each connected in series between an AC terminal of one of different phases of the inverter circuit and a motor, and a power conversion controller that generates gate signals to control operations of the inverter circuit and the three single-phase bridge circuits based on phase voltage commands. When a semiconductor switching element of the single-phase bridge circuits fails, the power conversion controller sets the output voltage of the single-phase bridge circuit of a phase to which the faulty semiconductor switching element belongs to zero to continue operation.