Spinning Frame DC Voltage Equalization

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Solution Overview

Problem

Spinning machines with multiple DC voltage sources face issues with asymmetric loading due to voltage drops or uneven operation of motors, leading to potential power supply failures.

Innovation Solution

A spinning machine design with two DC voltage networks (N1 and N2) of opposite polarities, connected through a voltage compensation device using frequency converters and an isolating transformer, ensures voltage balance by shifting energy between networks, maintaining a constant sum of voltages and preventing asymmetric loading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If multiple DC voltage sources are used to supply different motors with different voltages, then motors can operate with high efficiency, but voltage asymmetry and power supply failures occur due to uneven loading

Engineering Contradiction:
Improvemotor efficiencyVSAvoidpower supply stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent combines multiple DC voltage sources (first DC voltage source with voltage U1 and second DC voltage source with voltage U2) into a unified power supply system with three DC voltage rails. The current collectors are connected to combinations of these rails, allowing motors to receive different voltages (U1, U2, or U1+U2) while maintaining system-level voltage balance through the shared third rail architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control unit continuously monitors the voltage levels in both DC networks and dynamically adjusts the connection configuration of current collectors to the DC rails. When voltage asymmetry is detected, the control unit reconfigures which motors connect to which rail combinations, actively balancing the load between the two DC voltage sources and preventing power supply failures.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If individual spindles are taken out of operation or voltage drops occur, then maintenance or voltage regulation is possible, but asymmetric loading increases and power supply becomes insufficient

Engineering Contradiction:
Improvemaintenance capabilityVSAvoidpower supply adequacy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system employs dynamic reconfiguration of motor connections to DC rails based on real-time operational status. When spindles are taken out for maintenance or voltage drops occur, the control unit dynamically adjusts which current collectors connect to which DC rail combinations, redistributing the load to maintain symmetric loading and prevent power supply insufficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical connection parameters (which current collectors connect to which DC rails) based on operational conditions. By dynamically altering the voltage supply configuration to motors, the system compensates for asymmetric loading caused by maintenance operations or voltage fluctuations, ensuring adequate power supply distribution.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If voltage levels differ between DC networks, then energy distribution can be optimized, but voltage uniformity across all consumers is compromised

Engineering Contradiction:
Improveenergy distribution efficiencyVSAvoidvoltage uniformity
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements local voltage optimization by allowing different motors to receive different voltage levels (U1, U2, or U1+U2) based on their specific power requirements and operational characteristics. Each motor's current collector can be selectively connected to different combinations of DC rails, providing locally optimized voltage supply while the overall system maintains balance through the control unit's coordination.

Inventive Principle:
Principle #3Local quality

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 maintains uniform voltage across all consumers, preventing power supply failures and ensuring stable operation even with irregular motor usage, by balancing voltages in both networks and compensating for voltage differences.

Implementation Method 1

The voltage equalization device thus increases the voltage in the lower-voltage DC network by drawing energy from the higher-voltage DC network

Methodology Applied
Scientific EffectElectrical energy transfer: Conduction (electrical)

Implementation Method 2

each of the DC networks N1 and N2 is assigned a frequency converter as a voltage equalization device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the frequency converters are connected to an isolation transformer on their output side

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3961898B1Spinning frame
Publication Date: 2023.01.25 MASCHINENFABRIK RIETER AG
  • EP3961898B1 patent drawingFigure 1
  • EP3961898B1 patent drawingFigure 2
  • EP3961898B1 patent drawingFigure 3

AI summary

A spinning machine has a plurality of workstations with electric drives, in particular DC motors (10, 11, 19), and with at least two DC voltage sources (2.1, 2.2) of voltages U1 and U2, each forming a DC voltage network N1 and N2. At least three DC voltage rails (3, 4, 7) are connected to the at least two DC voltage sources (2.1, 2.2) to supply a plurality of the drives, in particular the DC motors (10, 11, 19), such that the first DC voltage rail (3) is operatively connected to the first DC voltage source (2.1), the second DC voltage rail (4) to the second DC voltage source (2.2), and the third DC voltage rail (7) to the first DC voltage source (2.1) and the second DC voltage source (2.2).Current collectors of a large number of the drives, in particular the DC motors (19), are optionally connected to the first DC rail (3) and the third DC rail (7) or to the second DC rail (4) and the third DC rail (7). The two DC networks N1 and N2 are interconnected by a voltage equalization device (18) to compensate for voltage differences between them.