Motor Control Apparatus Phase Deviation Reduction
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Solution Overview
Problem
In image forming and reading apparatuses, the use of vector control for motor drive results in positioning accuracy issues due to phase deviations when switching between vector and synchronous control modes, especially when using permanent magnet rotors, leading to inaccurate object positioning.
Innovation Solution
A motor control apparatus with a phase determiner and a controller that employs distinct control modes for different rotational directions, using a first control mode for one direction and a second control mode for the reverse direction to minimize phase deviations, ensuring accurate positioning by switching between synchronous and vector control modes based on rotational direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vector control is used for motor drive, then the motor can be controlled without a position sensor, but positioning accuracy deteriorates due to phase deviations when switching between control modes
Solution Approach 1:
The control system is segmented into two distinct control modes: synchronous control mode for high-precision positioning and vector control mode for sensorless operation. The controller selectively switches between these modes based on operational requirements, allowing the system to achieve both sensorless capability and high positioning accuracy in different operating scenarios
Solution Approach 2:
The control mode is dynamically switched between synchronous control and vector control based on the operational state. During positioning operations, synchronous control is activated for precise phase control, while during continuous rotation, vector control is used for sensorless operation, optimizing performance for each specific task
2Manufacturing precision
If synchronous control mode is used for positioning, then positioning accuracy is improved, but the system becomes more complex requiring mode switching control
Solution Approach 1:
The controller is designed with multi-functionality to execute both synchronous control and vector control algorithms. This universal control capability allows the single controller to handle both high-precision positioning tasks and continuous rotation tasks, eliminating the need for separate control systems while maintaining positioning accuracy
Data Source
AI summary
A motor control apparatus operable to control a motor includes a phase determiner for determining a rotational phase of a rotor of the motor, and a controller having a first control mode for controlling a driving current flowing through a winding of the motor based on a current of a predetermined magnitude, and a second control mode for controlling a driving current flowing through the winding so that a deviation between a command phase representing a target phase of the rotor and a rotational phase determined by the phase determiner is reduced. The controller executes the first control mode without executing the second control mode in a case of rotating the motor in a first direction, and executes the second control mode in a case of rotating the motor in a second direction which is a reverse direction to the first direction.