Pre-charging Switch Arrangement Voltage Detection

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Solution Overview

Problem

Existing pre-charging switch arrangements for direct-current circuits, particularly in high-voltage applications, face challenges in reliably detecting the charge state of capacitors without complex and costly isolation, often requiring auxiliary relays and leading to potential short-circuit damage.

Innovation Solution

A pre-charging switch arrangement where the pre-charging resistor is indirectly connected to a device for detecting voltage, allowing voltage measurement at the resistor rather than the controllable switching elements, ensuring galvanic separation and reducing complexity, with a common input for the pre-charging switch and direct-current voltage converter to enhance energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If voltage is tapped at the controllable switching elements to monitor capacitor charge state, then charge state detection is enabled, but complex isolation and auxiliary relays are required leading to increased device complexity and cost

Engineering Contradiction:
Improvecharge state detectionVSAvoidisolation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a pre-charging resistor as an intermediary element through which the monitoring device can measure voltage to detect capacitor charge state. This mediator allows indirect measurement without direct connection to the controllable switching elements, thereby avoiding the need for complex isolation and auxiliary relays while maintaining accurate charge state detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If direct connection between high-voltage source and uncharged capacitor is made, then simple circuit structure is achieved, but short-circuit currents flow causing component damage

Engineering Contradiction:
Improvecircuit structureVSAvoidshort-circuit current
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary action by pre-charging the capacitor through the pre-charging resistor before connecting it to the high-voltage source. This preliminary charging process prevents dangerous in-rush currents from damaging components while maintaining a relatively simple circuit structure. The pre-charging switch controls this preliminary action sequence.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If auxiliary relays are used for galvanic separation in pre-charging switch arrangement, then reliable isolation is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvegalvanic separationVSAvoidauxiliary components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the unnecessary auxiliary relays from the circuit by repositioning the voltage monitoring point to the pre-charging resistor. This extraction eliminates the need for complex isolation mechanisms while maintaining reliable galvanic separation, as the monitoring device no longer needs to be isolated from the controllable switching elements.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables reliable detection of the capacitor's charge state with reduced complexity and cost, ensuring safe and efficient charging while minimizing the need for auxiliary relays and maintaining galvanic separation, resulting in a more compact and energy-efficient pre-charging switch arrangement.

Implementation Method 1

The capacitor is thereby charged by means of the pre-charging resistor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the pre-charging resistor is at least indirectly connected to a device for detecting the voltage across the pre-charging resistor

Methodology Applied
Scientific EffectVoltage detection: Ohm's Law

Data Source

PatentEP3111541B1Pre-charging switch arrangement, power supplying arrangement and method for connecting a load to a high direct-current voltage source
Publication Date: 2022.05.11 TE CONNECTIVITY GERMANY GMBH
  • EP3111541B1 patent drawingFigure 1~2
  • EP3111541B1 patent drawingFigure 3

AI summary

The invention relates to a pre-charging switch arrangement (1) for charging a capacitor (C) of a direct-current circuit(7), having a pre-charging resistor (RV) and apre-charging switch (SV). The invention further relates to a power supplying arrangement (5) for an electrical load and a method for connecting a loadto a high direct-current voltage source(B). In order to provide a pre-charging switch arrangement (1) by means of which acapacitor can be charged, the charge state of the capacitor can be detected and which ensures the greatest possible level of reliability, there is provision according to the invention for the pre-charging resistor(RV) to be at least indirectly connected to a device (3) for detecting the voltage (UV) acrossthe pre-charging resistor (RV). For the power supplying arrangement (5), there is provision for it to have a pre-charging switch arrangement (1) according to the invention which is connected parallel with a controllable switching element (S1, S2). For the method, there is provision according to the invention for the load to be connected to the high direct-current voltage source (B) depending on a voltage (Uv) across a pre-charging resistor (Rv) which is arranged between the high direct-current voltage source (B) and the load.