Conveyor Inverter Phase Synchronization Energy Control

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Solution Overview

Problem

Conveyor systems, such as escalators and belt conveyors, face challenges in power control due to complex control logic and the need for multiple sensors to manage speed changes and loading forecasts, which can lead to safety issues and increased energy consumption.

Innovation Solution

A conveyor system with a simplified power control system using an inverter that connects the motor directly to the electricity network based on loading conditions, eliminating the need for separate speed sensors and forecasting, by synchronizing the frequency and phase of the output voltage with the electricity source using a phase-locked loop and adjusting the amplitude of the output voltage according to load, reducing energy losses and enhancing safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If speed regulation is enabled during conveyor operation, then energy efficiency is improved by reducing speed during low loading, but safety risks increase due to potential dangerous situations from sudden speed changes

Engineering Contradiction:
Improveenergy consumptionVSAvoidsafety
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent extracts the speed regulation function from the main power supply system by introducing a separate frequency converter that operates independently. This allows speed control during low loading without affecting the main motor control system, thereby maintaining safety while achieving energy efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements preliminary action by using sensors to detect loading conditions in advance and forecast traffic flow changes. This allows the system to prepare for upcoming load changes and switch between frequency converter and direct network power supply accordingly, preventing dangerous situations while optimizing energy consumption.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If frequency converter is used for speed regulation, then energy efficiency is improved, but device complexity increases due to need for multiple sensors and complex control logic

Engineering Contradiction:
Improveenergy consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the power supply system into two independent paths: one through the frequency converter for speed regulation during low loading, and another direct connection to the electricity network for full power during high loading. This segmentation allows each subsystem to be optimized independently, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The frequency converter is designed to perform multiple functions: it serves as both a speed regulation device during low loading and as a power supply transition device when switching between loading conditions. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If direct connection to electricity network is implemented, then device complexity is reduced, but energy efficiency decreases due to inability to operate at reduced speed during low loading

Engineering Contradiction:
Improvecontrol system complexityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent implements dynamics by making the power supply configuration adaptable to changing loading conditions. The system dynamically switches between frequency converter-based speed regulation and direct network connection based on real-time sensor input and traffic flow forecasting, optimizing energy efficiency without requiring complex permanent control systems.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If speed change during operation is enabled, then adaptability is improved, but measurement precision requirements increase due to need for multiple speed sensors

Engineering Contradiction:
Improvespeed regulation capabilityVSAvoidspeed measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent introduces the frequency converter as an intermediary device that provides speed regulation without requiring direct speed sensing of the motor. The frequency converter controls motor speed through frequency adjustment of the power supply, eliminating the need for multiple speed sensors and reducing measurement precision requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution reduces the complexity of power control, eliminates the need for multiple sensors, and enhances safety by maintaining constant frequency and phase, allowing direct connection to the network without forecasting loading changes, thereby reducing energy consumption and operational complexity.

Implementation Method 1

synchronizing the frequency and phase of the output voltage with the electricity source using a phase-locked loop

Methodology Applied
Scientific EffectPhase-locked loop:

Data Source

PatentEP2265533B1Conveyor system
Publication Date: 2019.12.11 KONE OYJ
  • EP2265533B1 patent drawingFigure 1~2
  • EP2265533B1 patent drawingFigure 3~4
  • EP2265533B1 patent drawingFigure 5

AI summary

The invention relates to a conveyor system, which comprises an identification (2) of the presence of a load (16) of the conveyor. The conveyor system comprises an electric motor (4) for moving the conveyor, and also a power supply appliance (3) for supplying power between the electric motor (4) and the alternating-electricity source (6) of the conveyor system. The power supply appliance comprises an inverter (7, 8). In the invention the frequency and phase of the output voltage of the inverter are adjusted with an inverter control (10) directly on the basis of the frequency and phase of the voltage of the alternating-electricity source (6).