Current Sensor Diagnostics Using Rotor-Angle Complex Current Sum
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Solution Overview
Problem
Conventional methods for diagnosing current sensors in electric drive systems are unreliable under dynamic operating conditions and fail to detect errors in current sensors with varying amplification factors or asymmetrical resistances.
Innovation Solution
A method and device for monitoring current sensors that calculate a complex current sum using rotor angle, separating it into real and imaginary portions, and determining a complex amplification error to check for plausibility, allowing reliable diagnostics even under dynamic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diagnostic methods are used for current sensors, then the system structure remains simple, but the reliability of sensor error detection deteriorates under dynamic conditions and asymmetrical resistances
Solution Approach 1:
The patent replaces conventional mechanical/electrical diagnostic approaches with a mathematical field-based solution. By using complex number transformations and rotor-angle-based coordinate transformations, the system substitutes physical measurement modifications with computational mathematics, achieving reliable error detection without adding physical diagnostic hardware.
Solution Approach 2:
The patent transforms the diagnostic approach by changing the mathematical parameters used for sensor evaluation. Instead of directly monitoring sensor outputs, the system transforms current measurements into complex number space using rotor angle information, calculating amplification errors in this transformed parameter space, thereby achieving reliable diagnostics under varying operating conditions.
2Measurement precision
If conventional sensor monitoring methods are used, then the calculation process remains simple, but the measurement precision of gain error detection deteriorates under dynamic conditions
Solution Approach 1:
The patent introduces a new mathematical dimension by transforming real-valued current measurements into complex number space. This dimensional transformation allows the system to separate and analyze different error components (real and imaginary parts of amplification error) independently, improving measurement precision while managing calculation complexity through structured mathematical operations.
3Speed
If rapid diagnostics are implemented under dynamic conditions, then the speed of error detection increases, but the difficulty of detecting and measuring gain errors increases due to phase current variations
Solution Approach 1:
The patent applies preliminary transformation of sensor measurements into complex number space using rotor angle information before error analysis. This preliminary action in the mathematical domain prepares the data in a form that enables rapid and accurate gain error detection, even under dynamic operating conditions with varying phase currents.
Data Source
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 current sum can be calculated using the rotor angle of the electric machine. This complex current sum is based on the current RMS current in the electric drive system in order to indicate deviations in the current gain factors of the current sensors used.