Stepping Motor Driving Device Peak Current Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stepping motor driving technologies for timepieces result in a peak consumption current, leading to rapid battery drain due to increased power consumption from internal resistance, as the time period with both coils energized exceeds the time period with only one coil energized.
Innovation Solution
A stepping motor driving device with a motor control unit that applies a predetermined voltage to one coil in the first phase, to the second coil in the second phase, and alternately to both coils in the third phase, with the on and off states of MOSFETs in the bridge circuit switched in a complementary manner during the third phase to reduce peak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both coils are energized simultaneously for a longer time period, then the motor can be rotated more effectively, but the peak consumption current increases and battery drains rapidly
Solution Approach 1:
The patent applies periodic action by dividing the motor rotation into three distinct phases: first phase energizes only the first coil, second phase energizes only the second coil, and third phase alternately energizes both coils. This periodic switching pattern prevents simultaneous continuous energization of both coils, thereby reducing peak current consumption and extending battery life while maintaining effective motor rotation through cumulative magnetic field effects across the phases.
2Use of energy by moving object
If the time period with both coils energized is shortened, then battery consumption is reduced, but the motor rotation effectiveness decreases
Solution Approach 1:
The periodic three-phase control ensures that both coils are energized alternately rather than simultaneously, distributing the energy demand across time. The third phase alternately activates both coils in a periodic manner, maintaining sufficient magnetic field strength for effective rotation while preventing the sustained dual-coil energization that would cause excessive battery drain.
Solution Approach 2:
The first and second phases preliminarily energize individual coils before the third phase alternately energizes both coils. This preliminary action builds up magnetic field momentum progressively, allowing the motor to maintain rotation effectiveness without requiring prolonged simultaneous energization of both coils, thus reducing overall battery consumption.
3Device complexity
If a simple two-phase control is used, then the device complexity is low, but a peak current appears that rapidly drains the battery
Solution Approach 1:
The control circuit maintains relative simplicity while implementing periodic three-phase switching. The periodic nature of the control logic (first phase, second phase, third phase repetition) provides a straightforward implementation approach that does not significantly increase device complexity compared to two-phase control, yet effectively reduces peak current and battery consumption through the alternating energization pattern.
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
This approach suppresses the peak current and associated power loss, thereby reducing battery drain and extending the life of the power source.
Implementation Method 1
a stepping motor configured to rotate forward and reversely is used for a timepiece... By appropriately applying driving pulses to the two coils, the stepping motor is rotated
Data Source
AI summary
A stepping motor driving device drives a first coil and a second coil. The stepping motor driving device includes a motor control unit. The motor control unit applies a predetermined voltage to the first coil in a first phase, applies the predetermined voltage to the second coil in a second phase after the first phase, and alternately applies the predetermined voltage to the first coil and the second coil in a third phase after the second phase.