Stepping Motor Auto-Decay Control for Current Ripple Suppression
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Solution Overview
Problem
Conventional motor driving devices face issues with current ripples and reduced average electric current due to the influence of counter electromotive force, particularly in slow and fast decay modes, leading to increased vibration and power loss.
Innovation Solution
A motor driving device with an auto-decay mode that dynamically adjusts the ratio and timing of slow and fast decay modes based on detected coil current values, extending decay time in subsequent cycles to maintain optimal current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If slow decay mode is used to reduce current ripples, then current ripple is reduced, but average electric current decreases and motor torque is weakened
Solution Approach 1:
The patent implements dynamic switching between slow decay mode and fast decay mode based on real-time detection of coil current values. The control device transitions from a static decay mode to a dynamic hybrid mode that adapts to changing operating conditions, allowing the system to optimize between current ripple reduction and torque maintenance according to the motor's instantaneous state
Solution Approach 2:
The patent changes the decay mode parameter dynamically by switching between slow decay and fast decay modes. This parameter change is triggered when the coil current reaches a predetermined threshold value, allowing the system to adjust the decay characteristics to maintain both low current ripple and sufficient average current for motor torque
2Power
If fast decay mode is used to increase average electric current, then average electric current increases, but current ripples increase and motor vibration increases
Solution Approach 1:
The system dynamically selects between fast decay mode and slow decay mode based on detected coil current values. When current is high, fast decay mode is used to maintain average current; when current reaches a threshold, the system transitions to slow decay mode to reduce ripples, creating a dynamic balance between the two opposing requirements
Solution Approach 2:
The patent implements periodic switching between fast decay mode and slow decay mode based on the coil current reaching predetermined values. This periodic action allows the system to repeatedly alternate between modes that favor average current and modes that favor ripple reduction, maintaining overall system performance
3Reliability
If decay time is extended in subsequent cycles, then counter electromotive force is suppressed and current control is optimized, but response time increases
Solution Approach 1:
The patent uses feedback from coil current detection to control the switching between decay modes. The control device monitors the coil current value and uses this feedback to determine when to switch from fast decay to slow decay mode, ensuring that the extended decay time is applied only when it benefits current control precision and not when it would unnecessarily delay response
Data Source
AI summary
A motor driving device and driving method of the same used to surely suppress the influence of counter electromotive force is provided. The motor driving device 100 includes an auto-decay portion 141. The auto-decay portion 141 controls a path of a electric current flow in a motor coil when supplying the electric current and when decaying the electric current. The influence of counter electromotive force generated in a stepping motor 200 can be suppressed by the auto-decay portion 141 configured to control so that a ratio or an decay time of a slow decay mode and a fast decay mode of previous cycle is different from a ratio or an decay time of the slow decay mode and the fast decay mode of current cycle.