Shared Frequency Converter Layout for Multi-Motor Propulsion

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Solution Overview

Problem

Existing drive systems for household appliances, such as washing machines, require additional electronic components and space for frequency converters, which increase costs and energy consumption, especially for simple applications where controlled motor operation is not necessary.

Innovation Solution

A drive system utilizing a three-phase motor with a frequency converter that can operate both three-phase and single-phase synchronous motors with reduced electronic effort, using half-bridges and changeover switches to share circuitry and minimize components, allowing for parallel or alternative operation of multiple motors with minimal additional circuitry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a frequency converter is used to control synchronous motors, then controlled operation (direction, speed, torque) is achieved, but additional costs, installation space, and electronic complexity increase

Engineering Contradiction:
Improvecontrolled operationVSAvoidelectronic complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The frequency converter is designed with multiple output terminals that can connect to different motors (three-phase motor, first single-phase motor, second single-phase motor). The same frequency converter unit performs multiple functions by serving different motor types through its multiple terminals, eliminating the need for separate frequency converters for each motor type.

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

Solution Approach 2:

The patent combines the control of multiple different motor types (three-phase and single-phase motors) into a single frequency converter unit. By merging the control functions and using a common power supply and control circuitry, the system reduces overall electronic complexity and component count while maintaining controlled operation capabilities.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If multiple frequency converters are used for multiple motors, then each motor can be controlled independently, but manufacturing costs and space requirements increase

Engineering Contradiction:
Improveindependent controlVSAvoidinstallation space
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The frequency converter incorporates multiple output terminals (first, second, third, fourth terminals) that enable connection to different motor types. This universal design allows a single device to replace multiple dedicated frequency converters, reducing installation space while maintaining the ability to control each motor independently through its respective terminals.

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

3Reliability

If separate control circuits are used for three-phase and single-phase motors, then each motor type can be optimized, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvemotor optimizationVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control circuits for three-phase and single-phase motors into a single integrated frequency converter. The power supply unit and control logic are shared across all motor types, reducing circuit complexity while maintaining optimized control for each motor type through dedicated output terminals and phase configurations.

Inventive Principle:
Principle #5Merging (Combining)

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 manufacturing costs, space requirements, energy consumption, and waste heat while maintaining full performance capabilities for each motor, enabling cost-effective and energy-efficient operation of multiple motors within a household appliance.

Implementation Method 1

The frequency converter can generate an electric rotating field with variable voltage amplitudes and/or variable rotational frequency

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a constantly magnetized rotor is used, which can also be referred to as a rotor. Permanent magnets or an external electromagnetic excitation can be used for this

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentEP4372977A1Propulsion system
Publication Date: 2024.05.22 MIELE & CO KG
  • EP4372977A1 patent drawingFigure 1
  • EP4372977A1 patent drawingFigure 2
  • EP4372977A1 patent drawingFigure 3

AI summary

Drive system (1) with at least one three-phase motor (M3) and with at least one frequency converter (15) having a first half-bridge (12), a second half-bridge (13) and a third half-bridge (14), wherein the frequency converter (15) is configured to operate the three-phase motor (M3) by means of all three half-bridges (12, 13, 14), characterized further by at least one first single-phase motor (M1a) and further by at least one second single-phase motor (M1b), wherein the frequency converter (15) is further configured to operate the three-phase motor (M3) only by means of the first half-bridge (12) and the third half-bridge (14) or only by means of the second half-bridge (13) and the third half-bridge (14), and to operate the first single-phase motor (M1a) by means of the first half-bridge (12) and the third half-bridge (14) alternatively or additionally to the three-phase motor (M3).wherein the first half-bridge (12) can be switched between the three-phase motor (M3) and the first single-phase motor (M1a) by means of a first changeover switch (16a), and the second single-phase motor (M1b) can be operated alternatively or additionally to the three-phase motor (M3) by means of the second half-bridge (13) and the third half-bridge (14), wherein the second half-bridge (13) can be switched between the three-phase motor (M3) and the second single-phase motor (M1b) by means of a second changeover switch (16b), and wherein the third half-bridge (14) is connected to both the three-phase motor (M3) and the first single-phase motor (M1a) and the second single-phase motor (M1b).