Electric Drive Current Sensor Diagnostics Under Dynamic Conditions
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Solution Overview
Problem
Conventional methods for diagnosing current sensors in electric drive systems are inadequate under dynamic conditions and asymmetrical resistances, leading to unreliable sensor data and potential system malfunctions.
Innovation Solution
A method and device for monitoring current sensors that calculate a complex gain error by summing phase currents, separating into real and imaginary parts, and filtering these components to determine if the gain error exceeds a threshold, enabling reliable diagnosis under dynamic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diagnosis methods are used for current sensors, then the system structure remains simple, but the reliability of sensor data becomes unreliable under dynamic conditions and asymmetrical resistances
Solution Approach 1:
The patent transforms the diagnosis approach by changing the parameter representation from simple current values to complex current sums with real and imaginary parts. By representing currents as complex numbers and calculating their sums, the method enables reliable detection of sensor malfunctions under dynamic conditions while maintaining a manageable computational complexity through standardized calculation steps.
Solution Approach 2:
The patent introduces a new dimension to the diagnosis by separating the current sum into real and imaginary parts. This dimensional transformation allows the system to analyze sensor data from multiple perspectives simultaneously, improving reliability by detecting malfunctions that would be invisible in traditional single-dimension current monitoring.
2Measurement precision
If simple current sum monitoring is used, then the calculation process remains simple, but the detection precision of sensor malfunctions is insufficient under dynamic conditions
Solution Approach 1:
The patent enhances detection precision by transforming current measurements into complex numbers and calculating their sums. This parameter change from real-valued currents to complex-valued current sums enables the system to distinguish between normal dynamic variations and actual sensor malfunctions, significantly improving measurement precision while keeping the calculation process structured and manageable.
3Measurement precision
If complex gain error calculation with filtering is implemented, then the accuracy of malfunction detection improves, but the calculation time and processing complexity increase
Solution Approach 1:
The patent applies filtering operations to the real and imaginary parts of the current sum before calculating the gain error. This preliminary action of filtering removes noise and unnecessary variations in advance, which actually reduces the overall calculation time by eliminating the need for more complex post-processing operations and enabling more accurate results with fewer computational iterations.
Data Source
Figure 1~2
AI summary
The invention relates to current sensor diagnostics in an electric drive system. According to the invention, a net current is formed from the sensor values provided by the current sensors. If this net current deviates significantly from zero, a complex net current can be calculated using the rotor angle of the electric machine. This complex net current is based on the current RMS current in the electric drive system in order to indicate deviations in the current amplification factors of the current sensors used.