Electric Motor Torque Control with Adaptive Correction
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Solution Overview
Problem
Existing control devices for electric rotary machines in motor vehicles face challenges in maintaining controllability of rotation speed, particularly when the target rotation speed differs significantly from the actual speed, leading to excessive correction torque and potential deviation from the target speed.
Innovation Solution
A control device with an instruction torque calculation means, correction torque calculation means, correction means, and correction rate correction means that adjusts the correction torque to minimize the difference between target and actual rotation speeds, using a reflection coefficient to prevent excessive correction and maintain controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the correction torque is increased to reduce the difference between target rotation speed and actual rotation speed, then the followability of actual rotation speed to target rotation speed is improved, but the controllability of rotation speed is reduced due to excessive correction
Solution Approach 1:
The patent applies dynamics by making the correction torque calculation adaptive rather than static. The correction torque calculation section dynamically adjusts the correction amount based on the current state of the system, specifically using the change rate of the target rotation speed and the rotation speed difference to modulate the correction torque in real-time, preventing both excessive and insufficient correction.
Solution Approach 2:
The patent changes the parameters used in correction torque calculation from fixed values to variable parameters that depend on the operating conditions. The correction torque is calculated using the change rate of target rotation speed and the rotation speed difference as variable parameters, allowing the system to adapt the correction amount to the current state, thereby maintaining controllability while improving followability.
2Speed
If the target rotation speed is adjusted to decrease the difference between target and actual rotation speed, then the followability is improved, but the correction torque significantly deviates from its optimal value causing actual rotation speed to separate from target speed
Solution Approach 1:
The patent implements feedback control by continuously monitoring the rotation speed difference between the actual and target values, and using this information to adjust the correction torque. The correction torque calculation section receives feedback about the rotation speed difference and change rate, and dynamically adjusts the correction amount to maintain optimal correction accuracy throughout the speed adjustment process.
Solution Approach 2:
The patent applies preliminary action by calculating and applying correction torque based on the predicted change rate of the target rotation speed before the actual deviation becomes large. The correction torque calculation uses the change rate information to proactively adjust the torque, preventing significant deviations rather than reacting to them after they occur.
Data Source
AI summary
A MGECU in a control device mounted on a vehicle has a feedback control section, a correction torque calculation section, an instruction torque calculation section. The feedback control section calculates a torque to be used for performing a feedback control of an actual rotation speed to follow a target rotation speed. The correction torque calculation section calculates a correction torque based on a change rate of the target rotation speed and inertia of a rotary body which includes the motor generator. When the target rotation speed is changed to decrease a difference between the target rotation speed and the actual rotation speed, the correction torque calculation section reduces the correction torque. The instruction torque calculation section adds the torque calculated by the feedback control section and the correction torque calculated by the correction torque calculation section in order to obtain the instruction torque to be used for the motor generator.