Stepper Motor Drive Apparatus Lead Angle Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Stepping motors experience step out issues when switching from feedback control to open-loop control due to phase differences in electrification switching and rotor position, leading to torque reduction and synchronization problems at high speeds.
Innovation Solution
A drive apparatus with a magnet rotor, stator, coil, position detector, lead angle circuit, and drivers that adjust the lead angle to synchronize electrification switching with rotor position, preventing step out by using a controller to switch between open-loop and feedback control modes while maintaining torque stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedback control is used to enable high-velocity driving, then the rotor can be driven at high speed, but phase difference between electrification switching and rotor position causes step out when switching to open-loop control
Solution Approach 1:
The lead angle circuit performs preliminary action by advancing the electrification switching signal phase relative to the rotor position detector output. This pre-advancement compensates for the phase difference that would otherwise occur during mode switching, ensuring smooth transition from feedback to open-loop control without step out.
Solution Approach 2:
The system dynamically changes the lead angle parameter based on operating conditions. By adjusting the lead angle amount according to rotor speed and load conditions, the system optimizes the phase relationship between electrification switching and rotor position, preventing step out during control mode transitions.
2Speed
If lead angle is increased to advance electrification switching for early coil excitation, then high-velocity driving is improved, but phase mismatch with open-loop control causes step out during switching
Solution Approach 1:
The lead angle is made dynamic rather than fixed. The lead angle circuit continuously adjusts the phase advance amount based on real-time rotor position and speed feedback, allowing the system to adapt the lead angle for high-speed performance while automatically reducing it during mode transitions to ensure smooth switching without step out.
3Measurement precision
If open-loop control is used for precise positioning, then positioning precision is achieved, but step out occurs when switching from feedback control due to phase difference
Solution Approach 1:
The lead angle circuit acts as an intermediary between the feedback control system and open-loop control system. It mediates the transition by adjusting the phase relationship of electrification signals, ensuring that the phase difference accumulated during feedback control does not cause step out when switching to open-loop control for precise positioning.
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 prevents step out by synchronizing electrification switching with rotor position, maintaining torque stability and preventing phase differences, thus ensuring precise positioning and high-velocity driving without step out.
Implementation Method 1
a coil configured to excite the magnetic pole portion
Implementation Method 2
a position detector configured to detect a position of the magnet rotor
Data Source
AI summary
A drive apparatus includes a magnet rotor, a stator having a coil, a position detector configured to detect a position of the magnet rotor, a lead angle circuit configured to output a signal having a lead angle relative to an output of the position detector, a first driver configured to switch an electrification state of the coil in accordance with a preset time interval, a second driver configured to switch an electrification state of the coil in accordance with an output of the lead angle circuit, and a controller configured to adjust a lead angle amount of the signal output from the lead angle circuit within a range that does not cause step out in the driving by the first driver, prior to changing the driving by the second driver to the driving by the first driver.