Shared DC Network Pre-Charging Circuit Design

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Solution Overview

Problem

Existing pre-charging circuits for DC voltage networks require multiple components, incur electrical losses, and need specific configuration for each section, making them inefficient and costly for equalizing voltages across sections.

Innovation Solution

A pre-charging circuit that efficiently transmits energy between sections using an inductive energy path with diode groups and a switching device, allowing only the section with the highest voltage to supply energy and the lowest voltage to receive it, minimizing losses and eliminating the need for multiple converters or resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pre-charging circuit with resistor and switch is used for each section, then the capacitive energy store can be precharged before connection, but electrical losses occur in the resistor and the configuration must be adapted for each section

Engineering Contradiction:
Improvepre-charging capabilityVSAvoidelectrical losses in resistor
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Multiple pre-charging circuits are merged into a single shared pre-charging circuit that serves all sections. The shared circuit includes one resistor and one switch that can pre-charge any section by connecting it to the common circuit, eliminating the need for individual resistors and switches for each section.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared pre-charging circuit is designed to be universal, capable of pre-charging any section of the DC voltage network regardless of which section it is. The circuit configuration allows the same resistor and switch to serve multiple sections by selectively connecting them to the common pre-charging circuit.

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

2Reliability

If a pre-charging circuit with resistor and switch is used for each section, then the capacitive energy store can be precharged, but each section requires its own pre-charging circuit increasing device complexity

Engineering Contradiction:
Improvepre-charging capabilityVSAvoidnumber of pre-charging circuits
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple pre-charging circuits are merged into a single shared pre-charging circuit that serves all sections. The shared circuit includes one resistor and one switch that can pre-charge any section by connecting it to the common circuit, eliminating the need for individual resistors and switches for each section.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared pre-charging circuit is designed to be universal, capable of pre-charging any section of the DC voltage network regardless of which section it is. The circuit configuration allows the same resistor and switch to serve multiple sections by selectively connecting them to the common pre-charging circuit.

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

3Loss of energy

If converters are used for pre-charging, then electrical losses are reduced, but a variable converter is still required for each section increasing device complexity and configuration requirements

Engineering Contradiction:
Improveelectrical losses during pre-chargingVSAvoidnumber of converters required
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

Multiple pre-charging circuits are merged into a single shared pre-charging circuit that serves all sections. The shared circuit includes one resistor and one switch that can pre-charge any section by connecting it to the common circuit, eliminating the need for individual resistors and switches for each section.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared pre-charging circuit is designed to be universal, capable of pre-charging any section of the DC voltage network regardless of which section it is. The circuit configuration allows the same resistor and switch to serve multiple sections by selectively connecting them to the common pre-charging circuit.

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

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 efficient, low-loss pre-charging across multiple sections with simplified design and control, reducing the need for specific configuration and component redundancy, while allowing for modular expansion and flexible power distribution.

Implementation Method 1

The energy transmission path is preferably designed as an inductive energy transmission path. As a result, energy can be transmitted efficiently and with little loss from one section to the other section.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3583672B1Efficient pre-charging of sections of a DC network
Publication Date: 2021.01.06 SIEMENS AG
  • EP3583672B1 patent drawingFigure 1
  • EP3583672B1 patent drawingFigure 2~3
  • EP3583672B1 patent drawingFigure 4

AI summary

The invention relates to a DC voltage network having a plurality of sections (1) which can be connected together and separated from one another individually or in groups via a respective switch element (5). A pre-charging circuit (10) has diode groups (11), a switch device (12), an energy transmission path (13), and a controller (14). Each of the sections (1) of the DC voltage network is coupled to the energy transmission path (13) via at least one respective diode group of the diode groups (11). The energy transmission path (13) is consistently the same for the diode groups (11). The controller (14) transmits a control signal (S) to the switch device (12) in order to pre-charge sections (1), and the switch device (12) thereby switches the energy transmission path (13) for all of the sections (1) coupled to the energy transmission path (13) so as to be conductive.