Power Inverter Fault Isolation Using Temperature Health Indicators
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Solution Overview
Problem
Current diagnostic systems for power inverter modules in electric vehicles often fail to accurately identify faults, leading to unnecessary replacement of entire modules instead of isolating specific component issues, such as temperature sensor faults, resulting in higher costs and inefficiencies.
Innovation Solution
A diagnostic system that includes a power loss estimating module, a junction temperature estimating module, and a health indicator generating module, which calculates and compares power losses and temperatures to identify inverter faults, temperature sensor faults, or no faults, allowing for selective component replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current diagnostic systems are used for power inverter modules, then fault detection is performed, but fault identification accuracy is poor leading to unnecessary replacement of entire modules
Solution Approach 1:
The diagnostic system segments the fault detection process into distinct components: power loss estimation, temperature estimation, health indicator generation, and fault identification. Each module processes specific parameters independently before integrating results, enabling precise localization of faults to specific components (temperature sensors, power switches, diodes) rather than treating the entire module as a single unit.
Solution Approach 2:
The system monitors multiple parameters simultaneously (power loss, junction temperature, case temperature, current, voltage) and changes the diagnostic approach based on the state of these parameters. By analyzing the relationship between estimated and measured temperatures, along with power loss data, the system dynamically identifies fault types and locations, improving both accuracy and repair efficiency.
2Reliability
If entire power inverter modules are replaced instead of isolating specific component issues, then system reliability is restored, but cost and time are increased
Solution Approach 1:
The diagnostic system performs preliminary fault identification before any replacement action is taken. By pre-analyzing power loss, temperature differentials, and health indicators, the system determines the exact faulty component in advance, allowing technicians to replace only the specific defective part rather than the entire module, thus reducing time and cost while maintaining reliability restoration.
Solution Approach 2:
The system substitutes physical inspection and trial-and-error replacement with an automated electronic diagnostic process. The controller electronically monitors and analyzes multiple parameters to identify faults, replacing the mechanical approach of module replacement with an intelligent software-based diagnosis that pinpointes specific failed components.
3Measurement precision
If multiple parameters are monitored and analyzed, then fault identification precision is improved, but system complexity is increased
Solution Approach 1:
The controller serves multiple functions: it acts as the power control system for the inverter, the temperature monitoring system, the power loss estimation system, and the fault diagnostic system. By integrating these functions into a single multi-functional controller, the system achieves high fault detection precision through multiple parameters while minimizing the increase in overall system complexity through functional consolidation.
Solution Approach 2:
The diagnostic system uses the existing sensor infrastructure (temperature sensors, current sensors, voltage measurements) already present in the power inverter module for its primary power control functions. These same sensors serve dual purposes: normal operation monitoring and fault diagnostic analysis, allowing the system to achieve enhanced diagnostic capability without adding significant complexity through self-service of existing components.
Data Source
AI summary
A diagnostic system for diagnosing faults in a power inverter including a power loss estimating module configured to calculate a power loss of one or more components of the power inverter. A junction temperature estimating module is configured to output an estimated junction temperature of the one or more components of the power inverter. A plurality of temperature sensors is configured to sense a plurality of temperatures of a plurality of inverter legs, respectively. A health indicator generating module is configured to generate a plurality of health indicators in response to the estimated junction temperature and the plurality of sensed temperatures of the plurality of inverter legs. A fault identification module is configured to selectively identify one of an inverter fault, a temperature sensor fault, and no fault in response to the plurality of health indicators.