Motor Direction Switching Using Open-Phase Voltage Thresholds
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Solution Overview
Problem
Existing motor control systems experience synchronization loss when switching the rotor direction due to variations in open-phase voltages, making it difficult to set fixed thresholds for avoiding synchronization loss.
Innovation Solution
A motor control method that dynamically sets thresholds based on real-time detection of open-phase voltages during energization mode switching, using initial thresholds and switching time detection values to minimize synchronization loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed thresholds are set for open-phase voltage to control energization mode switching, then the control system is simple to implement, but synchronization loss occurs when open-phase voltage varies due to individual motor differences
Solution Approach 1:
The patent applies dynamics by making the threshold values variable rather than fixed. The first and second thresholds are dynamically adjusted based on the detected open-phase voltages at the moment of energization mode switching. This allows the control system to adapt to individual motor variations without requiring complex pre-setting mechanisms, as the thresholds automatically adjust to the actual motor characteristics during operation.
Solution Approach 2:
The patent implements feedback by detecting the open-phase voltages at the time of energization mode switching and using these detected values to set the thresholds. This closed-loop feedback mechanism ensures that the thresholds accurately reflect the actual motor behavior, preventing synchronization loss while maintaining simple control logic. The feedback is obtained without requiring additional sensors or complex measurement systems.
2Reliability
If thresholds are set to avoid synchronization loss, then reliability improves, but it becomes difficult to set universal thresholds due to individual motor variability
Solution Approach 1:
The patent applies parameter changes by making the threshold values dependent on the detected open-phase voltage parameters at switching moments. Instead of using universal fixed thresholds, the first threshold is set based on the first open-phase voltage detected when switching to forward energization mode, and the second threshold is set based on the second open-phase voltage detected when switching to reverse energization mode. This parameter adaptation ensures reliable switching for each individual motor while maintaining the same control methodology across all motors.
3Measurement precision
If open-phase voltage detection is performed at all times, then synchronization accuracy is maintained, but energy consumption and system complexity increase
Solution Approach 1:
The patent applies periodic action by performing open-phase voltage detection only at specific moments when energization mode switching occurs, rather than continuously. The detection is triggered periodically at the transition points between forward and reverse energization modes, which is sufficient to capture the necessary voltage information for threshold setting. This approach maintains synchronization accuracy while minimizing energy consumption and processing requirements.
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
Reduces synchronization loss in electric motors by accurately adjusting energization modes based on detected open-phase voltages, ensuring smooth direction changes.
Implementation Method 1
a first open-phase voltage induced in an open phase when the first pulse is applied is detected, and a second open-phase voltage induced in an open phase when the second pulse is applied is detected
Data Source
AI summary
The rotor of an electric motor is rotated by sequentially switching the energization mode that determines two phases to which a pulse voltage is applied, among the three phases of the electric motor. The pulse voltage alternately generates a first pulse that rotates the rotor in one direction and a second pulse that has a polarity opposite to that of the first pulse and that rotates the rotor in the opposite direction. The energization mode is sequentially switched to the one direction or the opposite direction, based on the comparison between a value of a first open-phase voltage induced by application of the first pulse and a first threshold. The first threshold is set based on a value of the first open-phase voltage and a first initial threshold that is set in advance per energization mode.