Stepping Motor Driving Circuit Pulse Sequences
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Solution Overview
Problem
Reversible stepping motors used in analog electronic timepieces are unable to rotate the rotor at sufficiently high speeds due to a braking effect that limits rotation to one step at a time, preventing high-speed operation.
Innovation Solution
A motor driving apparatus that supplies specific sequences of driving pulses to a two-phase stepping motor, including first, second, third, and fourth pulses, in a controlled manner to generate magnetic fluxes that allow continuous high-speed rotation, with adjustable pulse lengths and energies, and optional standby times to manage rotor movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a third driving pulse with braking effect is input to prevent rotor from rotating more than one step, then positioning accuracy is improved, but rotation speed is reduced
Solution Approach 1:
The patent applies dynamics by making the driving pulse sequence adaptable between two modes: a four-pulse sequence for high-speed rotation and a three-pulse sequence for precise positioning. The system dynamically switches between these sequences based on operational requirements, allowing the rotor to rotate more than one step when needed while maintaining positioning accuracy when required.
Solution Approach 2:
The patent changes the parameter of pulse sequence length (from three pulses to four pulses) to resolve the contradiction. By introducing an additional driving pulse, the system enables continuous rotation without the braking effect that limits speed, while the ability to switch back to the three-pulse sequence preserves positioning accuracy when needed.
2Speed
If a four-pulse sequence is used for continuous rotation, then rotation speed is improved, but positioning precision may be reduced
Solution Approach 1:
The system dynamically selects between two driving pulse sequences based on the desired operation mode. When high-speed rotation is needed, the four-pulse sequence is used. When precise positioning is required, the system switches to the three-pulse sequence with braking effect, thus maintaining positioning precision while enabling high-speed operation when needed.
Solution Approach 2:
The patent makes the driving circuit universal by implementing both driving sequences within the same system. The control circuit can select between the four-pulse sequence for continuous rotation and the three-pulse sequence for precise positioning, allowing a single motor system to perform multiple functions with different performance characteristics.
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
Enables stable and continuous high-speed rotation of the rotor, overcoming the braking limitations of traditional reversible stepping motors by optimizing pulse sequences and energies, and managing standby times for efficient operation.
Implementation Method 1
a first driving pulse with which a first coil included in a two-phase stepping motor generates a first magnetic flux
Implementation Method 2
a second driving pulse with which a second coil included in a two-phase stepping motor generates a second magnetic flux opposite to the first magnetic flux
Data Source
AI summary
A motor driving apparatus including a driving circuit for supplying a first pulse with which a first coil included in a two-phase stepping motor generates a first magnetic flux, a second pulse with which a second coil included in the stepping motor generates a second magnetic flux opposite to the first magnetic flux, a third pulse with which the first coil generates the second magnetic flux, and a fourth pulse with which the second coil generates the first magnetic flux, to the stepping motor. The driving circuit supplies the second pulse, the third pulse, and the fourth pulse in this order to the stepping motor in a state of being stopped to start the stepping motor, and supplies the first pulse, the second pulse, the third pulse, and the fourth pulse in this order to the stepping motor after starting to continuously drive the stepping motor.