Inverter Sub-Module Abnormal Operation Detection
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Solution Overview
Problem
Existing diagnostic methods for hybrid and electric vehicle power systems fail to detect abnormal operation of three-phase PWM inverter modules, particularly when a switch fails or a gate drive circuit malfunctions, as they rely on zero current output, which is not indicative of all faulty scenarios.
Innovation Solution
A method and system that define sectors in current command signals based on phase angles and count consecutive amplitude measurements below or above thresholds to determine abnormal operation of inverter sub-modules, allowing for detection of faulty switches and other issues beyond open-circuit conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing diagnostic methods are used that check for zero current output, then open circuit conditions can be detected, but switch failures and gate drive circuit malfunctions cannot be detected
Solution Approach 1:
The patent changes the detection parameter from binary zero-current checking to continuous amplitude measurement within sector-defined angular ranges. By monitoring whether current amplitude remains below a threshold during specific sectors where it should be above threshold, the system detects abnormal operations including switch failures and gate drive malfunctions that previous methods missed.
Solution Approach 2:
The patent segments the current command signal into multiple sectors based on phase angles. Each sector corresponds to a specific angular range where the current should exhibit expected behavior. This segmentation allows the diagnostic system to check current amplitude against thresholds within specific sectors, enabling detection of various fault types including partial failures that don't result in complete zero current output.
2Reliability
If comprehensive diagnostic coverage is achieved by monitoring current amplitude in defined sectors, then detection capability improves, but system complexity increases
Solution Approach 1:
The patent implements a universal diagnostic approach using sector definitions and amplitude threshold comparisons that can detect multiple types of faults (open circuits, switch failures, gate drive malfunctions) through a single unified method. The same sector-amplitude comparison mechanism handles diverse fault scenarios, reducing the need for separate diagnostic circuits for each fault type and thereby limiting complexity growth.
3Measurement precision
If sector-based amplitude monitoring is implemented to detect abnormal operation, then detection accuracy improves, but measurement and detection difficulty increases
Solution Approach 1:
The patent performs preliminary action by pre-defining sectors based on phase angles of the current command signal before actual fault detection occurs. These sector boundaries and amplitude thresholds are established in advance, so during operation the system only needs to check whether current amplitude falls below the threshold within the currently active sector. This preliminary setup simplifies real-time measurement by converting a complex continuous analysis into discrete sector-based threshold comparisons.
Data Source
AI summary
Methods and apparatus are provided for determining whether one or more inverter sub-modules of an inverter module is operating properly. Amplitude of each stator current signal is regularly measured. For each current signal, a positive counter counts a number of consecutive times the amplitude of that current signal is less than a positive current threshold, while a negative counter counts a number of consecutive times the amplitude of that current signal is greater than a negative current threshold. If the positive counter or the negative counter exceeds a maximum count, it is determined that an inverter sub-module is operating abnormally.