Motor Control System Using Reverse Model Disturbance Observer
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Solution Overview
Problem
Permanent magnet type synchronous motors experience control stability degradation due to disturbances like back-emf, which conventional feed-forward and feedback control methods are sensitive to and require accurate motor speed measurements.
Innovation Solution
A motor control system that uses a reverse model-based disturbance observation part for current noise removal through differentiation filtering, determining a disturbance compensation amount using a gain, thereby enhancing operation stability and control responsibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feed-forward and feedback control methods are used to compensate disturbance, then disturbance compensation is achieved, but the control system becomes sensitive to parameter changes and requires accurate motor speed measurement
Solution Approach 1:
The patent inverts the conventional control approach by using a reverse model of the motor system. Instead of using the standard motor model for control, the patent applies the inverse model to estimate disturbances directly from measurable quantities like terminal voltage and current, eliminating the need for complex feed-forward and feedback control designs while reducing sensitivity to parameter variations.
2Ease of operation
If PI controller and linear feedback control are used for torque control, then current control is achieved, but control stability degrades due to back-emf disturbance
Solution Approach 1:
The patent introduces a disturbance observer as an intermediary component that estimates back-emf and other disturbances. This observer acts as a mediator between the control input and motor output, compensating for nonlinear effects before they degrade control stability, thereby maintaining ease of operation while improving stability.
Solution Approach 2:
The patent implements a disturbance observation mechanism that continuously monitors system behavior and feeds back disturbance estimates to the controller. This feedback loop compensates for back-emf effects in real-time, maintaining control stability without requiring complex control algorithms.
3Measurement precision
If disturbance observation is performed using motor model parameters, then disturbance estimation is achieved, but current noise affects measurement accuracy
Solution Approach 1:
The patent extracts the disturbance information from the motor model equations and processes it through a disturbance observer that separates disturbance estimation from noisy current measurements. By using terminal voltage and current to estimate back-emf through the reverse model, the system extracts useful disturbance information while filtering out noise components.
Data Source
AI summary
A motor control system is provided for compensating disturbance. The system includes a controller that supplies an input voltage to a motor based on the difference between a current command value to a motor and an actual current of the motor. A motor modeling part outputs a motor output current based on an input voltage from the controller and a disturbance observation part is formed as a reverse model of the motor modeling part to remove current noise using a current differentiation filtering method. Additionally, a disturbance compensation amount determination part determines a disturbance compensation amount based on the disturbance estimated by the disturbance observation part.