Electric Motor Torque Control via Rotor Temperature Feedback
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Solution Overview
Problem
The torque output of electric motors in vehicles varies with rotor temperature, leading to inefficiencies in hybrid vehicle propulsion systems, as existing control systems do not effectively account for temperature fluctuations in adjusting current commands for the electric motor.
Innovation Solution
An electric motor control system that adjusts d-axis and q-axis current commands based on rotor temperature, using a current command module, adjustment module, and switching control module to optimize power application to stator windings, thereby minimizing torque output discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing control systems use fixed current commands for the electric motor, then the control system is simple and easy to implement, but the torque output varies with rotor temperature leading to propulsion inefficiency
Solution Approach 1:
The control system dynamically adjusts current commands based on rotor temperature conditions. The controller modifies d-axis and q-axis current commands in real-time according to temperature feedback, transforming the static control system into a dynamic one that adapts to changing thermal conditions, thereby resolving the contradiction between simplicity and efficiency
Solution Approach 2:
The system changes control parameters (current commands) based on temperature variations. By monitoring rotor temperature and adjusting current magnitude and phase accordingly, the system optimizes torque output across different thermal states, improving propulsion efficiency without requiring fundamental system redesign
2Measurement precision
If the control system adjusts current commands based on rotor temperature, then torque output precision is improved, but the control system complexity increases
Solution Approach 1:
The control system implements temperature feedback by monitoring rotor temperature and using this information to adjust current commands. This closed-loop approach ensures torque output precision is maintained across varying thermal conditions, with the feedback mechanism integrated into the existing control architecture to minimize added complexity
Solution Approach 2:
The control system uses its own temperature measurements to self-adjust current commands without requiring external intervention. The controller autonomously modifies operating parameters based on internal temperature sensors, achieving precise torque control while keeping the system relatively simple through self-regulation
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
The system ensures more precise control of electric motor torque output, improving propulsion efficiency by accounting for rotor temperature variations, thus enhancing the overall performance of hybrid vehicles.
Implementation Method 1
apply power to stator windings of the electric motor from an energy storage device
Implementation Method 2
electric motor of a vehicle based on a temperature of a rotor of the electric motor
Data Source
AI summary
An electric motor control system of a vehicle includes a current command module configured to, based on a motor torque request for an electric motor of the vehicle, generate a first d-axis current command for the electric motor and a first q-axis current command for the electric motor. An adjustment module is configured to, based on a speed of a rotor of the electric motor and the motor torque request, selectively determine at least one of a d-axis current adjustment and a q-axis current adjustment based on a temperature of the rotor of the electric motor. An adjusting module is configured to produce a second d-axis current command for the electric motor by adjusting the first d-axis current command based on the d-axis current adjustment and to produce a second q-axis current command for the electric motor by adjusting the first q-axis current command based on the q-axis current adjustment.