Electric Drivetrain Inverter Diagnosis via Current Spectrum Analysis
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Solution Overview
Problem
Existing diagnostic methods for inverters in hybrid or electric vehicles are inadequate in detecting malfunctions and determining optimal operating frequencies, leading to potential inefficiencies and disturbances in vehicle operation.
Innovation Solution
A diagnostic method that involves continuously controlling the control frequency of the electric machine, measuring current variations between the battery, link capacitor, and inverter, and analyzing these variations using Fourier transforms to detect anomalies and determine optimal control frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional voltage measurement methods are used to detect transistor malfunctions, then the diagnostic system is simple, but it cannot detect anomalies caused by worn elements like the input inductance and cannot determine optimal operating frequencies
Solution Approach 1:
The patent replaces traditional voltage measurement methods with current measurement and Fourier transform analysis. Instead of measuring voltage between drain and source of transistors, the system measures current at the input of the inverter and analyzes its spectral content to detect anomalies in transistors, input inductance, and other components, enabling comprehensive diagnostic capability without additional hardware complexity
Solution Approach 2:
The patent introduces Fourier transform analysis as an intermediary method to bridge the gap between simple current measurement and comprehensive anomaly detection. By transforming time-domain current signals into frequency-domain spectral content, the system can identify anomalies caused by worn elements and determine optimal operating frequencies without directly complex measurement systems
2Power
If the inverter operates at high switching frequencies to improve power density, then power delivery is enhanced, but switching losses increase and noise is generated
Solution Approach 1:
The patent implements feedback by continuously monitoring the spectral content of the input current and using this information to adjust the switching frequency. The system identifies optimal frequency ranges where power delivery is maximized while switching losses and noise are minimized, creating a closed-loop control mechanism that adapts to the actual operating conditions and component wear state
Solution Approach 2:
The patent dynamically changes the switching frequency parameter based on real-time spectral analysis of the input current. By identifying optimal frequency ranges through Fourier transform analysis, the system adjusts the switching frequency to maintain efficient operation while avoiding excessive switching losses and noise generation, particularly important as components age
3Duration of action of stationary object
If worn elements like the input inductance continue to operate without detection, then the vehicle operates continuously, but electrical energy consumption increases and user experience deteriorates due to noise
Solution Approach 1:
The patent applies preliminary action by detecting anomalies in worn elements like the input inductance before they cause significant energy consumption increases or noise problems. Through continuous spectral analysis of the input current, the system identifies degradation trends early and can alert operators or adjust operating parameters to prevent excessive energy consumption and maintain optimal performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively detects anomalies in the inverter, preventing malfunctions and ensuring efficient operation of the electric machine by determining optimal control frequencies, thereby improving vehicle performance and reducing energy consumption.
Implementation Method 1
determining the variation in the Fourier transform of the current variation received as a function of the control frequency
Data Source
AI summary
A method for electronically diagnosing an electric drive chain for an electric or hybrid motor vehicle. The drive chain including an electric battery, an electric machine, an inverter connected between the battery and the electric machine, and a link capacitor connected in parallel between the battery and the inverter. The diagnosis method includes: i) continuously controlling the increase in the control frequency of the electric machine; ii) determining the variation in the Fourier transform of the current variation between the assembly comprising the battery and the link capacitor and between the inverter; iii) for each control frequency: 1) detecting an anomaly; 2) otherwise, determining when the control frequency value is optimal.