Step Motor Driving Device Phase Detection Power Reduction
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Solution Overview
Problem
Existing step motor driving devices face challenges in reducing power consumption while reliably reversing the rotor, especially when external factors cause positional deviations, making it difficult to correct the rotor's position without outputting the third pulse.
Innovation Solution
A step motor driving device with a rotor magnetized by two or more poles, a stator, and a coil, utilizing a drive circuit, phase detecting circuit, and control unit that outputs specific drive signals and detects counter-electromotive currents to determine the rotor's phase and control its rotation, allowing for reliable reversal with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three pulses (repulsion pulse G1, attraction pulse G2, and repulsion pulse G3) are output to reliably reverse the step motor, then the rotor reversal reliability is improved, but the power consumption increases
Solution Approach 1:
The invention uses a phase detecting circuit to detect the actual phase of the rotor by measuring counter-electromotive current after applying a measurement drive signal. Based on this feedback information, the control unit determines whether the rotor is in the desired phase or reversed phase, and selectively outputs only the necessary pulses (either one pulse for normal reversal or two pulses for corrected reversal), avoiding unnecessary third pulse output and reducing power consumption while maintaining reliability
Solution Approach 2:
The invention dynamically adjusts the driving method based on the detected rotor phase. When the rotor is in the desired phase, a first driving method outputs only one pulse. When the rotor is in the reversed phase, a second driving method outputs two pulses including a correction pulse. This dynamic adaptation allows the system to use the minimum necessary pulses for reliable reversal, reducing power consumption
2Use of energy by moving object
If only first pulse and second pulse are output to reduce power consumption, then the power consumption is reduced, but the rotor position correction capability deteriorates when external factors cause half-rotation deviation
Solution Approach 1:
The phase detecting circuit provides feedback on the rotor's actual phase by detecting counter-electromotive current. This feedback mechanism allows the control unit to identify when the rotor is in the reversed phase (indicating half-rotation deviation) and respond by outputting the appropriate correction pulse sequence, ensuring position correction capability is maintained only when necessary
Solution Approach 2:
A measurement drive signal is applied before the actual drive signal to detect the rotor's phase in advance. This preliminary action allows the system to determine the rotor's phase state beforehand and prepare the appropriate driving method (first or second), ensuring that correction capability is available when needed while avoiding unnecessary correction pulses
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 reliable reversal of the step motor while minimizing power dissipation, even in cases of positional deviations caused by external factors.
Implementation Method 1
a coil that generates a magnetic force toward the stator
Implementation Method 2
a phase detecting circuit that detects a counter-electromotive current that occurs in the coil after the output of the measurement drive signal
Data Source
AI summary
To reliably rotate a step motor while reducing power consumption, a step motor driving device includes a step motor that includes a rotor, stator, coil, driver circuit that outputs a measurement drive signal to the coil, phase detecting circuit that detects a counter-electromotive current that is generated in the coil after the output of the measurement drive signal and determines whether a phase of the rotor is a desired phase based on the detected counter-electromotive current, and a control unit that, if the phase is the desired phase, controls the step motor by a first driving method in which the drive circuit outputs a first drive signal for rotating the rotor by one step, and, if not, controls the step motor by a second driving method different from the first driving method so as to restrict the rotation of the rotor.