Two-Stage Pre-Charging Device for Voltage Converter Efficiency

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Solution Overview

Problem

Existing pre-charging mechanisms for voltage converters in electrified vehicles face challenges in achieving high efficiency, safety, and simplicity in voltage conversion between low-voltage and high-voltage networks.

Innovation Solution

A two-stage pre-charging device with a first pre-charging unit powered by an external low-voltage source and a second pre-charging unit with a charge pumping unit, along with a chopper, is used to efficiently charge a load from a low-voltage to a high-voltage state, incorporating a second pre-charging switching device with reverse series power switches for protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single-stage pre-charging mechanism is used, then the structure is simple, but the charging efficiency and voltage conversion performance are insufficient

Engineering Contradiction:
Improvecharging efficiencyVSAvoidpre-charging structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pre-charging device is divided into two distinct stages: a first pre-charging unit for initial charging and a second pre-charging unit with charge pumping for final voltage conversion. This segmentation allows each unit to be optimized for its specific function, improving overall charging efficiency while maintaining manageable structural complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Reliability

If high voltage is applied directly to the load, then voltage conversion is achieved, but over-current and over-voltage damage may occur

Engineering Contradiction:
Improveprotection against over-current and over-voltageVSAvoidprotection mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The first pre-charging unit performs preliminary charging to bring the load voltage close to the target high voltage before the second pre-charging unit takes over. This preliminary action prevents sudden high-voltage application that would cause over-current and over-voltage damage, while the second unit's charge pumping mechanism provides controlled voltage adjustment with inherent protection capabilities.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a two-stage pre-charging mechanism is implemented, then charging efficiency and safety are improved, but the device complexity increases

Engineering Contradiction:
Improvecharging safetyVSAvoidpre-charging unit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The two pre-charging units are merged into a single integrated pre-charging device that shares common control logic and power management circuits. This merging approach allows the system to achieve improved reliability and charging safety through coordinated operation of both stages, while avoiding the complexity increase that would result from completely separate control systems for each stage.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution enables efficient and safe voltage conversion, ensuring high efficiency and reliability in charging the load from 12V to 48V or 60V, while preventing over-current and over-voltage damage, thus enhancing the overall performance of the voltage converter.

Implementation Method 1

a second pre-charging unit connected to an internal power supply and comprising a charge pumping unit, configured for converting a received voltage and outputting a predetermined constant voltage

Methodology Applied
Scientific EffectCharge pumping: Capacitance

Data Source

PatentEP4201732A1A pre-charging device, a voltage converter and an electrified vehicle
Publication Date: 2023.06.28 VALEO ELECTRIFICATION
  • EP4201732A1 patent drawingFigure 1
  • EP4201732A1 patent drawingFigure 2
  • EP4201732A1 patent drawingFigure 3

AI summary

The present disclosure discloses a pre-charging device, which comprises a first pre-charging unit connected to an external power supply and is used to provide first-stage pre-charging for a load, and a second pre-charging unit connected to an internal power supply and comprising a charge pump unit, which is used to convert a received voltage and output a predetermined constant voltage during the process of providing a second pre-charging stage for the load. The present disclosure also discloses a voltage converter and an electrified vehicle.