Motor Oil Temperature Control Using Back-EMF Estimation
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Solution Overview
Problem
Existing electric vehicle driving systems require separate sensors to measure motor and oil temperatures, which can be inefficient due to small changes in oil temperature and increased production costs.
Innovation Solution
Estimating oil temperature using the back electromotive force (EMF) of the motor, eliminating the need for separate oil temperature sensors, and controlling the oil pump based on the estimated temperature and coil temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sensors are used to measure motor coil temperature and oil temperature, then temperature measurement accuracy is improved, but device complexity and production cost increase
Solution Approach 1:
The patent uses the back electromotive force signal (which is already present in the motor system) as a copy or proxy for temperature information. Instead of directly measuring oil temperature with a separate sensor, the system derives temperature estimates from the back EMF signal that naturally occurs during motor operation, thereby avoiding additional sensors while obtaining useful temperature data
Solution Approach 2:
The back electromotive force acts as an intermediary that indirectly provides temperature information. The relationship between back EMF and temperature serves as a mediating mechanism, allowing the system to infer oil temperature without direct measurement, thus resolving the contradiction between measurement accuracy and device complexity
2Reliability
If separate sensors are used to measure motor coil temperature and oil temperature, then temperature monitoring reliability is improved, but production cost increases
Solution Approach 1:
The patent derives temperature information from existing back EMF signals rather than requiring separate temperature sensors. This copying approach uses already-present electrical signals to obtain temperature data, reducing component count and production cost while maintaining monitoring capability through the established back EMF-temperature relationship
3Loss of information
If oil temperature is measured with a separate sensor, then direct temperature data is obtained, but measurement efficiency decreases due to small temperature changes
Solution Approach 1:
The patent replaces the mechanical/physical temperature sensor measurement system with an electrical signal-based measurement approach. By substituting direct thermal contact measurement with back EMF signal analysis, the system achieves temperature monitoring without the inefficiencies associated with small temperature change detection by traditional sensors
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 allows for efficient oil temperature estimation and control without additional sensors, reducing production costs and improving cooling efficiency in electric vehicles.
Implementation Method 1
the back electromotive force of the motor may appear inversely proportional to the temperature, and the changes in the temperature and the back electromotive force may appear linearly after a predetermined period
Data Source
AI summary
The present disclosure relates to oil temperature control device and method of a vehicle including a motor, and more particularly, to oil temperature control device and method for estimating and controlling an oil temperature by using a back electromotive force of a motor.