Switchgear Cabinet Cooling Power Supply for Wide-Range AC Input

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Solution Overview

Problem

Existing cooling devices require multiple designs to accommodate different input AC voltages, necessitating adaptation of electrical components to specific mains voltages, which increases complexity and costs.

Innovation Solution

A cooling device with a power supply featuring a step-up and/or step-down converter, rectifier, and a three-phase inverter that converts single-phase or multi-phase AC voltages to a DC voltage, allowing operation with a nominal three-phase voltage, eliminating the need for multiple voltage variants in components like fans and compressors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple voltage variants are provided for different mains voltages, then the cooling device can be operated in different geographic areas, but the device complexity and manufacturing costs increase

Engineering Contradiction:
Improveoperational voltage rangeVSAvoidcomponent voltage variants
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The power supply unit is designed to accept multiple AC voltages (single-phase 115V/230V, three-phase 230V/400V/460V) and convert them to a standardized DC link voltage, making the entire cooling device universally operable across different geographic regions without requiring voltage-specific component variants

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

Solution Approach 2:

A DC link with capacitor is introduced as an intermediary between the AC input and the motor drives. The step-up/step-down converter converts all AC voltage variants to a standardized DC link voltage, which then supplies both the three-phase inverter for the compressor and the power supply unit for fans, eliminating the need for multiple voltage-specific designs

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple voltage variants are provided for different mains voltages, then the cooling device can be operated in different geographic areas, but the manufacturing costs increase

Engineering Contradiction:
Improveoperational voltage rangeVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The power supply unit is designed to accept multiple AC voltages (single-phase 115V/230V, three-phase 230V/400V/460V) and convert them to a standardized DC link voltage, making the entire cooling device universally operable across different geographic regions without requiring voltage-specific component variants

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

Solution Approach 2:

The step-up/step-down converter dynamically adjusts the DC link voltage based on the input AC voltage and the operational requirements (compressor power, fan power) to optimize efficiency across different voltage inputs while using the same hardware platform

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a standardized power supply design is used for all voltage variants, then the device complexity is reduced, but the ability to operate with different input voltages must be ensured

Engineering Contradiction:
Improvecomponent design simplificationVSAvoidinput voltage compatibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

A DC link with capacitor is introduced as an intermediary between the AC input and the motor drives. The step-up/step-down converter converts all AC voltage variants to a standardized DC link voltage, which then supplies both the three-phase inverter for the compressor and the power supply unit for fans, eliminating the need for multiple voltage-specific designs

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

Enables a single design to operate across a wide range of input AC voltages (100 V - 460 V), simplifying component design and reducing the need for voltage adaptation, while maintaining efficient compressor and fan performance.

Implementation Method 1

a power supply with a step-up and/or a step-down converter which is connected via a rectifier to a wide-range input for single-phase or multi-phase AC voltage

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

a step-up and/or a step-down converter which is connected via a rectifier to a wide-range input for single-phase or multi-phase AC voltage and charges a capacitor to an intermediate circuit voltage

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

a three-phase inverter which provides three-phase current for the compressor

Methodology Applied
Scientific EffectInversion: Electromagnetic Induction

Implementation Method 4

charges a capacitor to an intermediate circuit voltage which is above or below is below a mains voltage applied to the wide-range input

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 5

a first fan for switching cabinet air to flow through a first heat exchanger and a second fan for ambient air to flow through a second heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 6

a first fan for switching cabinet air to flow through a first heat exchanger and a second fan for ambient air to flow through a second heat exchanger

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 7

a compressor-driven cooling circuit with a compressor

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3152989B1Cooling device, in particular for cooling components housed in a switchgear cabinet, corresponding use and corresponding method
Publication Date: 2018.03.14 RITTALWERK RUDOLF LOH GMBH & CO KG
  • EP3152989B1 patent drawingFigure 1

AI summary

The invention relates to a cooling device, in particular for cooling components housed in a switchgear cabinet, having a first cooling fan for blowing air from the switchgear cabinet through a first heat exchanger, and a second cooling fan for blowing ambient air through a second heat exchanger, the cooling device being characterised in that it further comprises a power supply (1) with a step-up and/or step-down converter (2) connected via a rectifier (3) to a wide-range input (4) for single-phase or multiphase alternating voltage, and charges a capacitor (5) to a DC link voltage higher or lower than a mains voltage across the wide-range input (4), a mains power pack (6) of at least one of the two cooling fans being connected in parallel to the capacitor (5). The invention further relates to the use of such a cooling device and to a corresponding method for operating the cooling device.