Power Converter Capacitor Pre-Charging for Pulse Current Protection
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Solution Overview
Problem
The challenge in electric vehicle battery charging is ensuring normal charging processes while preventing high pulse currents that can damage components in power conversion devices, particularly due to the high voltage and current outputs from charging apparatuses.
Innovation Solution
A pre-charging method for power conversion devices that involves receiving charging readiness messages from both the battery management system and the charging apparatus, performing pre-charging by charging a capacitor, and managing output suspensions or permissions to prevent high pulse currents, ensuring safe and secure charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the charging apparatus outputs high voltage and current to charge the power battery quickly, then the charging speed is improved, but the capacitor in the power conversion device generates high pulse current causing damage
Solution Approach 1:
The patent applies preliminary action by performing pre-charging of the capacitor before the main charging process. The control unit detects charging readiness messages and initiates pre-charging of the capacitor through the charging apparatus, ensuring the capacitor is charged to a safe voltage level before allowing high-power charging to begin. This prevents high pulse current damage while enabling fast charging.
2Reliability
If the pre-charging process is extended to fully charge the capacitor, then the safety is improved, but the charging time is increased
Solution Approach 1:
The patent applies partial action by charging the capacitor only to a sufficient level during pre-charging, not to complete saturation. The control unit monitors the pre-charging process and stops it when the capacitor reaches adequate voltage to prevent high pulse current, without requiring full charging. This balances safety requirements with time efficiency.
3Strength
If the power conversion device waits for pre-charging completion before accepting charging power, then the component protection is improved, but the charging efficiency is reduced
Solution Approach 1:
The patent applies feedback by implementing continuous monitoring of the capacitor voltage and charging status. The control unit receives charging readiness messages from both the power battery management system and charging apparatus, tracks the pre-charging progress, and dynamically controls the charging process. When pre-charging is sufficient, the control unit allows charging power to be accepted, optimizing both protection and efficiency.
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 method ensures normal charging security by preventing high pulse currents, thereby protecting components and maintaining the integrity of the charging process.
Implementation Method 1
performing a pre-charging, wherein the pre-charging includes charging a capacitor in the power conversion device
Data Source
AI summary
Embodiments of the present application provide a pre-charging method of a power conversion device and a power conversion device. The power conversion device is used for a power conversion between a charging pile and a power battery and the method includes: receiving, by the power conversion device, a first message transmitted by a battery management system of the power battery, where the first message is used to indicate a charging readiness of the battery management system; and forwarding, by the power conversion device, the first message to the charging pile and performing a pre-charging, where the pre-charging includes charging a capacitor in the power conversion device. The technical solution in embodiments of the present application is capable of ensuring normal performing of a charging process.