Motor Control Apparatus for Butting Position Learning
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Solution Overview
Problem
Existing motor control systems face precision issues in learning a reference position due to varying torque caused by temperature and aging changes, especially when using duty-controlled current methods, which lead to reduced accuracy in butting control.
Innovation Solution
A motor control apparatus that uses a current sensor to perform constant current control and sequentially switches the current supply phase using a one-phase or two-phase current supply method to maintain a constant torque, thereby stabilizing the current value and improving reference position learning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If duty-controlled current method is used in butting control, then voltage control is simplified, but torque varies due to coil resistance changes caused by temperature and aging changes, lowering learning precision
Solution Approach 1:
The patent changes the control parameter from voltage-based duty control to current-based constant control. By detecting the sum of currents flowing in plural phases and maintaining it constant, the system compensates for coil resistance changes due to temperature and aging, thereby maintaining constant torque and improving reference position learning precision.
2Productivity
If one-two phase current supply method is used while performing constant current control, then current supply efficiency is improved, but current value changes at every switchover between one-phase and two-phase current supply, causing torque changes and lowering learning precision
Solution Approach 1:
The patent applies preliminary action by pre-planning the current supply phase switching sequence to ensure smooth transitions. The control unit switches current supply phases in a predetermined sequence that maintains constant current magnitude, preventing torque fluctuations during phase transitions and improving learning precision while preserving efficiency benefits.
3Measurement precision
If constant current control is performed without fixed number of current supply phases, then torque can be maintained constant, but system complexity increases and efficiency decreases
Solution Approach 1:
The patent segments the current supply into discrete phases (one-phase or two-phase current supply) with a fixed number of active phases. This segmentation approach maintains constant torque through constant current control while avoiding the complexity of continuously variable phase control, achieving a balance between precision and system simplicity.
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 solution effectively suppresses torque variations caused by temperature and aging changes, maintaining a constant current value and enhancing the precision of reference position learning during butting control.
Implementation Method 1
a current sensor for detecting a sum of currents flowing in plural phases of a motor
Implementation Method 2
a motor having plural phases and driving a control object
Data Source
AI summary
In a butting control, while performing a constant current control for a motor based on an output of a current sensor, the motor is driven by sequentially switching over a current supply phase of the motor in a one-phase current supply method, in which only one of the phases of the motor is powered. By performing the constant current control in the butting control, changes in a current value of each phase caused by temperature changes or aging changes is suppressed and hence a torque change of the motor is suppressed. In addition, by sequentially switching over the current supply phase of the motor in the one phase current supply method under the constant current control, a torque change of the motor can be suppressed while maintaining the current value of the current supply phase at a constant value.