Vehicle Motor Torque Control via Adaptive Phase Temperature Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle drive motor control systems face challenges in preventing heat-related negative influences on phase coils when motor torque fluctuates or current distribution states change, leading to potential torque drops due to inaccurate temperature estimation.
Innovation Solution
A control system that includes a motor torque obtaining portion, a current distributing state obtaining portion, and a temperature sensor to update other phase estimated temperatures based on the combination of motor torque and current distribution state, ensuring accurate temperature estimation and limiting motor torque before heat allowable limits are exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one temperature sensor is provided to correspond to a specific phase coil and other phase coil temperatures are estimated, then cost and control complexity are reduced, but temperature estimation accuracy deteriorates when motor torque fluctuates or current distribution changes
Solution Approach 1:
The patent applies dynamics by making the temperature estimation method adaptive to changing operating conditions. The control device dynamically switches between different estimation approaches: using temperature rise per unit time when motor torque is constant, and using detected temperatures from other phase coils when motor torque fluctuates. This dynamic adaptation resolves the contradiction by maintaining estimation accuracy across varying conditions while keeping the sensor configuration simple.
Solution Approach 2:
The patent changes the estimation parameters based on operating conditions. When motor torque fluctuates, the system changes from using a fixed temperature rise rate to using actual detected temperatures of other phase coils as the estimation basis. This parameter change allows accurate temperature estimation under varying load conditions while maintaining cost-effectiveness through single-sensor configuration.
2Reliability
If motor torque is reduced early based on estimated reach time, then heat damage to other phase coils is prevented, but unintended torque drops occur when actual reach time is later than estimated
Solution Approach 1:
The patent implements feedback by continuously monitoring detected temperatures of phase coils and using this information to adjust torque control decisions. When the detected temperature difference between phase coils exceeds the threshold or motor torque fluctuates, the system feedbacks to switch to a more accurate estimation method, preventing both premature torque reduction and heat damage while maintaining productivity.
Solution Approach 2:
The patent applies preliminary action by preparing multiple estimation methods in advance and selecting the appropriate one based on current operating conditions. The system pre-establishes threshold values for temperature differences and has ready the alternative estimation approach, allowing it to respond quickly to changing conditions without causing torque drops or heat damage.
3Measurement precision
If three temperature sensors are provided to correspond to U-phase, V-phase, and W-phase coils respectively, then temperature detection accuracy is improved, but cost and control complexity increase
Solution Approach 1:
The patent uses copying by creating virtual temperature data for phase coils without physical sensors. When motor torque fluctuates or temperature difference exceeds thresholds, the system copies temperature information from detected phase coils to estimate temperatures of other phases, achieving accurate multi-phase temperature monitoring through single-sensor physical configuration, thus reducing cost and complexity while maintaining precision.
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 approach enhances estimation accuracy of other phase temperatures, preventing heat-related adverse effects and maintaining motor torque until heat allowable limits are approached, thereby minimizing unintended torque drops.
Implementation Method 1
a temperature sensor (for example, a thermistor) which is provided to the stator of the motor
Implementation Method 2
updating other phase estimated temperatures by using a detected temperature of a specific phase coil and an added-up value of temperature rises per unit time of other phase coils
Data Source
AI summary
A control system for a vehicle drive motor includes a motor torque obtaining portion, a current distributing state obtaining portion obtaining a state of current distribution to coils of respective phases of a stator of the motor, a temperature sensor detecting temperature of a specific phase coil, a motor torque control portion updating other phase estimated temperatures by using the coil sensor temperature and an added-up value of a temperature rise per unit time of each of other phase coils at each time point, the motor torque control portion controlling the motor torque by using the other phase estimated temperatures, wherein the temperature rise per unit time of each of the other phase coils at each time point is determined by the motor torque control portion in accordance with a combination of the motor torque and the state of current distribution at each time point.