Multiphase Converter Switch Fault Detection via Alpha-Beta Frames
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Solution Overview
Problem
Existing power converters struggle to accurately detect and differentiate between open circuit and short circuit faults in power switches, particularly in multiphase AC output systems, which can lead to operational complications.
Innovation Solution
A method and system using alpha-beta transformations in multiple reference frames to calculate and analyze alpha and beta currents and voltages to identify specific power switch faults, including open circuit and short circuit faults, by determining the signs and absolute voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault detection methods are used in power converters, then the system structure remains simple, but the ability to accurately detect and differentiate between open circuit and short circuit faults in power switches is insufficient
Solution Approach 1:
The fault detection method segments the analysis by dividing the three-phase current signals into different reference frames (stationary alpha-beta frame and rotating dq frames). By transforming the currents into multiple reference frames and analyzing the signs of current components in each frame, the system can identify specific fault types (open circuit or short circuit) and locate faulty switches. This segmentation of the analysis process enables precise fault differentiation without requiring complex additional hardware.
Solution Approach 2:
The invention adds dimensional transformation by converting three-phase current signals into multiple reference frames (stationary and rotating frames). This dimensional change allows the same physical fault to manifest with different sign patterns across multiple reference frames, enabling unique identification of fault types and locations. The multi-dimensional analysis space provides sufficient information to distinguish between various fault conditions using only software-based signal processing.
2Productivity
If multiple power switches are used to produce multiphase AC output power, then the power converter capability is improved, but the difficulty of identifying the specific failed power switch increases
Solution Approach 1:
The method segments the fault identification process by analyzing current signs in multiple reference frames. Each reference frame provides a different perspective on the same fault condition, and by comparing the sign patterns across frames, the system can pinpoint the specific faulty switch among multiple switches. This segmented analysis approach scales to multiphase systems without requiring additional sensors or complex hardware modifications.
Solution Approach 2:
The system uses feedback from current sign analysis in multiple reference frames to identify faulty switches. By continuously monitoring the signs of current components in stationary and rotating reference frames, the system provides real-time feedback about switch status. This feedback mechanism enables automatic identification of specific failed switches in multiphase configurations, allowing for rapid diagnosis and maintenance planning.
Data Source
AI summary
A system, method, and/or programming instructions for detecting a fault in a power switch in a circuit having a plurality of power switches for converting direct current (DC) to multiphase alternating current (AC) output power, the system configured to: calculate alpha currents and/or beta currents using respective alpha-beta transformations in each of a multiple of different reference frames; check the signs of the alpha currents and/or the beta currents calculated in each of the multiple of different reference frames; and determine, based upon the signs of at least one of the alpha currents, the beta currents, and the combinations thereof calculated in each of the multiple of different reference frames, whether one of a short circuit fault or an open circuit fault occurred in one of the plurality of power switches.