Stepping Motor Control with Temperature-Adaptive Back-EMF Thresholds
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Solution Overview
Problem
Existing motor control devices that measure back electromotive voltage to detect out-of-step in stepping motors face accuracy issues at high and low temperature conditions, with no effective solutions provided in existing technologies.
Innovation Solution
A motor control device that measures back electromotive voltage and acquires temperature information to adjust detection criteria, using a detecting unit to compare the measured voltage with temperature-specific thresholds to reliably detect out-of-step conditions across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back electromotive voltage measurement is used to detect out-of-step, then out-of-step detection capability is provided, but detection accuracy deteriorates at high and low temperature conditions
Solution Approach 1:
The patent changes the detection threshold parameter based on temperature conditions. The control circuit sets different out-of-step detection thresholds according to the measured temperature: a first threshold is used when temperature is between -30°C and 0°C, a second threshold when between 0°C and 40°C, and a third threshold when above 40°C. This parameter adaptation resolves the contradiction by maintaining detection accuracy across varying temperatures while preserving the out-of-step detection capability.
2Measurement precision
If temperature-specific detection thresholds are implemented, then detection accuracy across temperature ranges is improved, but device complexity increases
Solution Approach 1:
The control circuit performs self-adjustment by automatically selecting appropriate detection thresholds based on temperature measurements it conducts itself. The system uses its own temperature sensing capability to autonomously adapt the detection parameters without requiring external intervention or complex additional hardware, thus improving accuracy while limiting complexity growth.
Solution Approach 2:
The control circuit serves multiple functions: it controls motor operation, measures temperature, and performs out-of-step detection with adaptive thresholds. By integrating these functions into a single control unit, the patent achieves temperature-compensated detection accuracy without proportionally increasing overall device complexity.
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 enables accurate detection of out-of-step conditions in stepping motors, even at extreme temperatures, by setting temperature-dependent detection thresholds, improving reliability and reducing manufacturing costs through the use of existing temperature measurement components.
Implementation Method 1
a measuring unit for measuring a back electromotive voltage induced at a coil of a phase for which energization is stopped, among the multiple phase coils
Data Source
AI summary
There is provided a motor control device configured to control an energization state of a coil of each phase for driving a stepping motor having multiple phase coils. The motor control device includes a measuring unit configured to measure a back electromotive voltage induced at a coil of a phase for which energization is stopped, among the multiple phase coils, an acquiring unit configured to acquire temperature information on temperature of the stepping motor or on temperature corresponding to the temperature of the stepping motor, and a detecting unit configured to detect whether the stepping motor is out of step or not based on a result obtained by the measuring unit and the temperature information acquired by the acquiring unit.