Stepping Motor Pulse Control for Wide Voltage Stability
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Solution Overview
Problem
Analog electronic timepieces with two-phase stepping motors face challenges in maintaining stable operation across a wide voltage range, experiencing excessive torque at high voltages and insufficient torque at low voltages, and existing solutions complicate the system with rotation direction detection.
Innovation Solution
A motor driving apparatus with a pulse generation circuit that applies a drive pulse P1 and P2 to a two-phase stepping motor, where P1 has a stable stationary position at 90 degrees or less and P2 at 90 degrees or more, with P2 having greater energy and longer application time than P1, and including a waiting period to ensure stable operation across varying voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional pulse generation techniques are used to cover a wide voltage range, then the motor can operate at different voltages, but excessive torque occurs at high voltage and stepping out occurs at low voltage
Solution Approach 1:
The drive pulse is segmented into two distinct types: a first drive pulse for normal operation and a second drive pulse for high-voltage conditions. The pulse generation circuit selectively applies different pulse sequences based on voltage detection, dividing the control strategy into separate manageable segments that address different voltage ranges independently, thereby preventing torque instability across the wide voltage range
Solution Approach 2:
The invention changes the parameters of the drive pulse by detecting the power source voltage and switching between different pulse generation modes. When voltage exceeds a predetermined threshold, the circuit transitions from normal pulse generation to high-voltage-specific pulse generation, dynamically adjusting pulse characteristics to maintain stable torque output across varying voltage conditions
2Reliability
If rotation detection is performed to adjust pulse width for stable operation, then operation stability improves, but the system becomes complicated
Solution Approach 1:
The invention extracts and eliminates the rotation detection function from the system by using voltage-based pulse width adjustment instead. The pulse generation circuit directly modifies pulse characteristics based on detected voltage levels without requiring feedback from rotation detection circuits, thereby maintaining operation stability while significantly reducing system complexity
Solution Approach 2:
The voltage detection circuit serves as an intermediary that directly controls pulse generation without requiring rotation detection as an intermediate step. By using voltage level as the control parameter instead of rotation position feedback, the system achieves stable operation with a simpler architecture that bypasses the need for complex rotation detection and feedback loops
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 provides stable operation across a wide voltage range without using complex rotation direction detection, suppressing excessive torque at high voltages and ensuring sufficient torque at low voltages, thus preventing stepping out.
Implementation Method 1
a two-phase stepping motor including a rotor magnetized in two poles and a stator in which a two-phase coil is wound around a yoke
Data Source
AI summary
A motor driving apparatus is a pulse generation circuit applying a drive pulse for rotating a rotor to a two stepping motor including the rotor magnetized in two poles and a stator in which a two-phase coil is wound around a yoke. The drive pulse is constituted of a drive pulse P1 and a drive pulse P2. The pulse generation circuit applies the drive pulse P1 having a stable stationary position at which a rotor rotation angle from a reference position is 90 degrees or less and applies the drive pulse P2 having a stable stationary position at which the rotor rotation angle from the reference position is 90 degrees or more continuously to the application of the drive pulse P1.