Induction Motor Torque Control Using Pre-Calculated Look-Up Tables
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Solution Overview
Problem
Conventional torque control methods for induction motors in electric vehicles fail to accurately account for magnetic flux saturation and battery voltage changes, leading to inaccuracies in torque control.
Innovation Solution
A system and method utilizing two and one-dimensional look-up tables, generated through simulation, to output current and voltage commands for an induction motor, which include a current command unit, a flux/current controller, a PWM/gate driver, and an inverter, to modulate the torque control based on mutual inductance and rotor torque, thereby addressing magnetic flux saturation and battery voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional torque control methods are used, then the control system is simple, but torque control accuracy deteriorates due to magnetic flux saturation and battery voltage changes
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing current command values in look-up tables during the design phase. These tables contain pre-computed d-axis and q-axis current commands for various operating conditions, allowing the controller to quickly retrieve accurate current commands without real-time complex calculations, thus improving torque control accuracy while maintaining simple real-time control logic
Solution Approach 2:
The patent changes the control parameters by using multiple look-up tables for different battery voltage levels and motor temperature conditions. Each look-up table contains current command values optimized for specific operating conditions, allowing the system to adapt to magnetic flux saturation and voltage changes by selecting the appropriate pre-calculated parameter sets
2Adaptability or versatility
If temperature-based torque compensation is used, then temperature effects are addressed, but other factors like magnetic flux saturation and voltage changes are not considered
Solution Approach 1:
The patent implements universality by designing a control system that handles multiple operating conditions through a unified look-up table framework. The system uses separate look-up tables for different battery voltage levels and temperature conditions, allowing a single control architecture to adapt to various scenarios including magnetic flux saturation, voltage drops, and temperature variations, thereby achieving both versatility and accuracy
Data Source
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AI summary
Disclosed is a system and a method for controlling torque of induction motor in electric vehicle. The system and method for controlling torque of induction motor in electric vehicle according to the present disclosure has an advantageous effect in that torque control problems caused by saturation of magnetic flux, parameters of induction motor and changes in battery voltages during control of torque in the induction motor can be solved using a look-up table (a type of data table), thereby enhancing accuracy in torque control and improving travel performance and fuel efficiency of the electric vehicle.