Electric Motor Temperature Plausibility Check Using Virtual Sensing

The patent introduces a virtual temperature sensor that acts as an intermediary between the physical temperature sensor and the actual maximum temperature. The virtual sensor calculates the maximum temperature by combining the measured temperature from the physical sensor with modeled temperature differences, thereby indirectly obtaining the maximum temperature without placing a physical sensor at the exact location where it occurs.

The patent creates a virtual copy of the temperature measurement system that simulates the temperature distribution throughout the motor. Instead of placing multiple physical sensors to capture all temperature points, a virtual model replicates the temperature field based on limited sensor data and thermal modeling, providing temperature information at locations where no physical sensor exists.

The patent performs preliminary calibration of the thermal model during the manufacturing phase using controlled test bench measurements. The model parameters are pre-adjusted to match the specific motor's thermal characteristics before the motor enters service. This preliminary action eliminates the need for complex ongoing calibration and allows the model to provide accurate temperature estimates during normal operation.

The patent adjusts key thermal model parameters such as thermal conductivity, heat capacity, and heat transfer coefficients to match the actual motor's thermal behavior. By changing these parameters based on initial characterization measurements, the model accurately reflects the specific motor's thermal properties without requiring complex simulation for each operating condition.

The patent implements a feedback mechanism where the virtual temperature sensor continuously compares its calculated maximum temperature with the actual measured temperature from the physical sensor. This feedback loop detects discrepancies that indicate sensor drift, allowing the system to identify validation issues during steady-state operation when conventional methods would fail to detect problems.

The patent applies validation not only during transient conditions but also during steady-state operation by continuously comparing virtual and actual temperatures. This excessive validation approach ensures that sensor drift is detected even when temperature changes are minimal, going beyond the conventional practice of only monitoring during dynamic conditions.