Torque-Based Motor Starter Phase Sequential Switching

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Solution Overview

Problem

Switching devices in industrial and motor control applications experience issues with electric arcing, current oscillations, and reduced operational flexibility due to non-instantaneous switching and phase misalignment during motor restarts, which can lead to reduced lifespan and increased energy consumption.

Innovation Solution

Implementing a method for motor torque-based phase sequential switching that allows for precise control of switching devices to minimize arcing and oscillations by coordinating switching with specific points on the electric power waveform, enabling independent phase control and modular configuration for various applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If switching devices are opened and closed at specific points on the electric power waveform to reduce arcing and current oscillations, then the lifespan of switching devices is extended, but the device complexity increases due to the need for precise timing control

Engineering Contradiction:
Improvelifespan of switching devicesVSAvoidswitching control complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The control system determines the delay between when a make or break instruction is given and when the switching device actually makes or breaks. This preliminary determination of switching timing allows the system to pre-calculate the optimal switching points on the electric power waveform, enabling reduced arcing and current oscillations while managing complexity through advance planning rather than real-time complex control

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from monitoring the electric power waveform and actual switching device operation to adjust and refine switching timing. By continuously monitoring the waveform and comparing actual switching moments with ideal points, the control system optimizes switching timing to minimize arcing and oscillations while maintaining manageable complexity through adaptive correction

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If switching devices are used to provide electric power to electric motors with wye-delta configuration control, then operational flexibility is enhanced, but electric arcing and current oscillations increase during switching transitions

Engineering Contradiction:
Improveoperational flexibility of motor controlVSAvoidelectric arcing and current oscillations
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Before transitioning between wye and delta configurations, the control system determines the optimal switching points on the electric power waveform in advance. By pre-calculating when switching should occur based on the waveform characteristics, the system minimizes arcing and current oscillations during configuration transitions while maintaining the operational flexibility of wye-delta control

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the timing parameters of switching operations based on the electric power waveform characteristics. By adjusting switching timing to coincide with specific points on the waveform (such as voltage zero-crossings or current minima), the system reduces harmful effects during wye-delta transitions while preserving configuration flexibility

Inventive Principle:
Principle #35Parameter changes

3Reliability

If switching devices make or break with non-instantaneous action, then the switching process is more practical and safer, but the precision of switching timing is reduced leading to suboptimal arc reduction

Engineering Contradiction:
Improveswitching device reliabilityVSAvoidswitching timing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The control system determines the actual delay time between instruction and execution for each switching device in advance. By measuring and storing this delay information, the system can compensate for non-instantaneous switching action in subsequent operations, achieving both the practicality of non-instantaneous switching and the precision needed for optimal arc reduction

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces mechanical timing methods with electronic determination and control of switching timing. By using electronic sensors and control circuits to detect waveform points and calculate optimal switching moments, the system achieves high timing precision despite the non-instantaneous nature of mechanical switching device operation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Loss of energy

If fault testing is performed before fully connecting electric power to the load, then peak current and let through energy from faults are minimized, but the switching control complexity increases

Engineering Contradiction:
Improvepeak current and let through energy from faultsVSAvoidswitching control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The control system performs fault testing by closing switching devices at specific points on the electric power waveform before fully connecting power to the load. By pre-testing for faults at optimized timing points, the system minimizes peak current and let through energy from potential faults while managing complexity through systematic pre-testing procedures

Inventive Principle:
Principle #10Preliminary action

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 approach reduces the likelihood and magnitude of arcing and oscillations, enhances operational flexibility, and extends the lifespan of switching devices and motors by ensuring phase alignment during restarts, thereby improving energy efficiency and reducing wear on components.

Implementation Method 1

As the switching devices open or close, electric power may be discharged as an electric arc and/or cause current oscillations to be supplied to the load

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP3018675B1Torque-based stepwise motor starting
Publication Date: 2019.05.15 ROCKWELL AUTOMATION TECH INC
  • EP3018675B1 patent drawingFigure 1~3
  • EP3018675B1 patent drawingFigure 4A~4D
  • EP3018675B1 patent drawingFigure 5A~6

AI summary

One embodiment describes a method that includes determining a desired torque level of a motor actuated by a motor starter; determining, using a control system, a configuration of the motor starter to achieve the desired torque level, in which determining the configuration includes determining which of a plurality of switching devices in the motor starter should be opened and which should be closed; and instructing, using the control system, the motor starter to implement the determined configuration by opening or closing one or more of the plurality of switching devices.