Switching Device Arc-Free Shutdown Control

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Solution Overview

Problem

Switching devices used in industrial automation face limitations in the number of switching cycles due to wear caused by arcs formed when switching off the supply voltage, which reduces their operational lifespan.

Innovation Solution

A switching device with a control unit, energy store, and measuring device that monitors the supply voltage, allowing controlled switching by first enabling the semiconductor switch and then opening the electromechanical switches, using energy from the store to manage switching signals and prevent arcing during emergency shutdowns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electromechanical switches are used to control power supply, then reliable switching control is achieved, but arc wear reduces the number of switching cycles

Engineering Contradiction:

Improveswitching control reliabilityVSAvoidnumber of switching cycles

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The switching function is segmented between semiconductor switches (for frequent switching) and electromechanical switches (for isolation), allowing each component to operate within its optimal cycle life

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Semiconductor switches replace electromechanical switches for the main switching function, eliminating mechanical wear and arc damage while maintaining reliable control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If supply voltage is switched off for emergency shutdown, then safe motor shutdown is achieved, but arcs form on switches causing wear

Engineering Contradiction:

Improvesafe shutdown capabilityVSAvoidarcing and switch wear

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Energy is stored in capacitors during normal operation to enable preliminary action during emergencies - the stored energy allows semiconductor switches to be activated first, creating a zero-current switching condition that prevents arcs when electromechanical switches open

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Semiconductor switches replace the mechanical switching function during emergency shutdown, enabling controlled turn-off without mechanical contact separation and arc generation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-generated harmful factors

If semiconductor switches are used alone, then arc-free operation is achieved, but sufficient energy for switching signals may not be available during supply failure

Engineering Contradiction:

ImprovearcingVSAvoidenergy availability for switching

Core Design Contradiction:

Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

Energy is stored in advance in capacitors during normal operation, ensuring that sufficient energy is available to drive semiconductor switches during emergency shutdown even when supply voltage is lost

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Capacitors act as an energy intermediary, decoupling the energy storage function from the switching function, allowing semiconductor switches to operate independently of supply voltage during critical moments

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 approach enhances switching behavior, increases the number of switching cycles, and minimizes wear on switches by using stored energy for controlled shutdowns, ensuring safe and arc-free operation.

Implementation Method 1

a first energy store (6) connected to the supply connection (7) for storing energy

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a measuring device (8) by means of which the control unit (2) can monitor the energy supply via the supply connection (7)

Methodology Applied

Scientific EffectVoltage detection: Ohmmeter

Implementation Method 3

a semiconductor switch (12) which is connected in parallel to the second switch (13) and in series with the first switch (11)

Methodology Applied

Scientific EffectSemiconductor conduction: Conduction (electrical)

Data Source

PatentEP2873083B1Switching device for controlling power supply of a subsequent electrical motor

Publication Date: 2018.03.28 SIEMENS AG

Figure 1

AI summary

The invention relates to a switchgear (1) which comprises a control unit (2), a supply connection (7) and a first current path (15), the first current path (15) comprising a first electromechanical switch (11) and, connected in series to the first switch (11), a parallel connection of a second electromechanical switch (13) to a semiconductor switch (12). In order to make a switchgear (1) available which allows an increased number of switching operations, the switchgear (1) comprises an energy accumulator (6) and a measuring device (8), the control unit (2) being capable of monitoring, by means of the measuring device (8), the energy supply coming in through the supply connection (7). The control unit (2) is designed such that, if the energy supply coming in through the supply connection (7) reaches a critical range, it controls the output of the switching signals by means of the energy of the energy accumulator (6) such that: in a first step, the semiconductor switch (12) is switched to be electrically conducting and the second switch (13) is then opened, and in a second step following the first step, the semiconductor switch (12) is switched to be electrically non-conducting and the second switch (11) is then opened.