Adaptive Phase Shift Control for Asynchronous Motor Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling asynchronous phase-shift motors in rolling shutters require manual adjustment of phase shift limit values, which are inaccurate due to motor parameters like temperature, leading to potential motor damage and user safety issues.
Innovation Solution
A method that continuously calculates and updates the limit phase shift deviation based on current and voltage phase shift measurements, allowing for adaptive control independent of motor characteristics, using a microcontroller to monitor and stop the motor before excessive load is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment of phase shift limit values is used, then the control system is simple, but the measurement precision is poor due to motor parameters like temperature
Solution Approach 1:
The system automatically determines the phase shift limit value by monitoring the phase shift evolution during motor operation and detecting when the apron comes into abutment. This self-adjusting mechanism eliminates manual calibration and compensates for temperature variations and motor parameter changes without requiring external intervention or complex calibration procedures.
Solution Approach 2:
The control system continuously monitors the phase shift between voltage and current during motor operation and uses this feedback to automatically determine the appropriate limit value. By detecting the characteristic phase shift evolution pattern when the apron reaches its travel limit, the system adapts the limit value dynamically, improving measurement precision while maintaining relatively simple system architecture.
2Reliability
If fixed phase shift threshold is used, then the control method is simple, but the reliability is poor due to temperature and load variations
Solution Approach 1:
The phase shift limit value transitions from a fixed parameter to a dynamic value that automatically adapts to changing operating conditions. The system determines the limit value based on the actual phase shift evolution during motor operation, which inherently accounts for temperature changes, load variations, and motor characteristic drift, thereby improving reliability without requiring complex adaptive algorithms.
Solution Approach 2:
The control method changes the phase shift limit parameter from a static predetermined value to a dynamic value determined during operation. By monitoring how the phase shift evolves in real-time and identifying the characteristic pattern when abutment occurs, the system automatically adjusts the limit parameter to match current operating conditions, enhancing reliability under varying temperature and load conditions.
3Adaptability or versatility
If site adjustment is required for each motor, then the adaptability is poor, but the device complexity is reduced
Solution Approach 1:
Each motor automatically determines its own phase shift limit value through the monitoring and detection process, eliminating the need for manual site adjustment or calibration procedures. The system adapts to each specific motor's characteristics autonomously by analyzing the phase shift evolution pattern during operation, providing universal adaptability across different motors without requiring technician intervention or complex adjustment procedures.
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 self-adaptive system ensures accurate and safe motor control, preventing damage and user hazards by dynamically adjusting the phase shift threshold according to real-time conditions, eliminating the need for manual adjustments and accounting for temperature and load variations.
Implementation Method 1
two coils with opposite windings. These coils have one of their ends connected to a common while their other ends, called connectable terminals, are connected to each other by a phase shift capacitor
Implementation Method 2
an asynchronous motor mechanically coupled to the winding axis of the curtain
Data Source
Figure 1
AI summary
The method involves periodically determining a phase difference variation limit value from a measured current/voltage phase difference by taking into account the temperature, usury of the motor and friction condition of the apron. A real voltage/current phase difference is measured. A motor driving a roller shutter is stopped, when the shutter attains a higher position and/or lower position, by comparing real phase difference with the calculated limit value. An independent claim is also included for a unit for implementing an asynchronous motor controlling method.