Voltage Transformation for Single-Phase Induction Motor Load Monitoring

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Solution Overview

Problem

Existing methods for transforming and analyzing voltages at the terminals of single-phase induction motors with permanent capacitors are inefficient due to long processing times and failure to consider alternating voltages directly, leading to incomplete load monitoring.

Innovation Solution

A method that transforms alternating voltages into image voltages using potentiometric dividers and voltage shift units, allowing for direct analog-digital conversion and efficient load determination by processing both positive and negative alternations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rectified and filtered voltages are used for transformation, then the voltage can be converted for analysis, but the processing time becomes long (at least one mains period)

Engineering Contradiction:
Improvevoltage transformation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the necessary transformation function from the complex rectification and filtering process. By using a potentiometric divider to directly transform the alternating voltage into an image voltage suitable for ADC conversion, the method eliminates the time-consuming rectification and filtering stages while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical process of rectification and filtering with a direct potentiometric transformation. This substitution allows the alternating voltage to be converted into a usable image voltage without undergoing the traditional multi-stage processing, thereby reducing processing time to well under one mains period.

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

2Ease of operation

If half-wave voltages are used for processing, then the voltage transformation can be performed, but the processing time cannot be less than the mains period

Engineering Contradiction:
Improvevoltage processing simplicityVSAvoidprocessing time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent processes both positive and negative alternations of the alternating voltage simultaneously through the potentiometric divider. This continuous processing of the full wave form, rather than waiting for half-wave completion, enables the transformation to be completed in less than one mains period while maintaining operational simplicity.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If voltage amplitudes are combined instead of alternating voltages, then the analysis can be performed, but incomplete load monitoring occurs

Engineering Contradiction:
Improveload monitoring accuracyVSAvoidload variation information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

Instead of combining voltage amplitudes and then analyzing, the patent inverts the approach by directly transforming the alternating voltages themselves into image voltages that preserve the temporal and amplitude information. This allows the ADC to capture the complete voltage waveform characteristics, enabling accurate detection of load variations including stops and obstacles.

Inventive Principle:
Principle #13The other way round (Inversion)

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 enables rapid and accurate monitoring of motor loads, reducing processing time and improving the precision of load determination by considering both positive and negative alternations, thus enhancing the efficiency of motor control and load analysis.

Implementation Method 1

each of which consists of two resistors in series with one another and with a voltage source

Methodology Applied
Scientific EffectVoltage division: Ohm's Law

Implementation Method 2

A DC voltage generator is connected in series between the midpoint of the two resistors and the analog input of the converter and presents a direct voltage component

Methodology Applied
Scientific EffectVoltage addition: Ohm's Law

Data Source

PatentEP2099123B1Method for transforming voltages at the terminals of the windings of a single-phase electric motor with permanent condenser and induction
Publication Date: 2012.06.20 SOMFY SAS
  • EP2099123B1 patent drawingFigure 1~4
  • EP2099123B1 patent drawingFigure 5~7
  • EP2099123B1 patent drawing

AI summary

The method involves applying initial voltages (U1, U2) respectively at terminals of windings (W1, W2) without rectifying the initial voltages and with a ratio potentiometric divider. Each of the initial voltages at terminals of the windings are divided by constant ratios, and one of positive direct components (E1, E2) is added at the divided initial voltages such that the initial voltages are transformed at the terminals of the windings by an affine function. Independent claims are also included for the following: (1) a method for determining a load of a permanent condenser and induction single-phase electric motor of an actuator that controls a mobile load of a home automation installation (2) a device for determining a load of a permanent condenser and induction single-phase electric motor of an actuator that controls a mobile load of a home automation installation, comprising an initial voltage transformation device.