EV Charger DC Bus Capacitive Filtering for Load-Dump Overvoltage
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Solution Overview
Problem
Existing electric vehicle charging arrangements experience large overvoltage spikes due to electrical energy accumulation in the DC bus during load dumps, which can damage the vehicle and compromise safety.
Innovation Solution
Incorporating a capacitive filter on the DC bus and within the electric vehicle charger to absorb excess energy, thereby limiting overvoltage to below 2,500 V and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a DC bus with inductance is used to transport DC from power cabinet to electric vehicle charger, then efficient power transmission is achieved, but large overvoltage spikes occur during load dump events
Solution Approach 1:
A capacitive filter is introduced as an intermediary component between the power cabinet and electric vehicle charger. The capacitive filter absorbs the inductive energy during load dump events, preventing overvoltage spikes from reaching the electric vehicle while maintaining efficient power transmission through the DC bus
2Object-affected harmful factors
If the DC bus inductance is reduced to minimize overvoltage spikes, then overvoltage protection is improved, but power transmission capability and stability are degraded
Solution Approach 1:
Rather than reducing the DC bus inductance, a capacitive filter is placed as an intermediary to handle the inductive energy during load dump events. This approach maintains the power transmission capability and stability provided by the inductive DC bus while protecting against overvoltage spikes
3Device complexity
If no capacitive filter is installed, then device complexity is minimized, but overvoltage damage to electric vehicle occurs
Solution Approach 1:
A capacitive filter is installed as a relatively simple intermediary component that provides substantial protection against overvoltage damage. The capacitive filter absorbs inductive energy during load dump events, significantly improving electric vehicle reliability while adding minimal complexity to the charging system
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 capacitive filter effectively mitigates overvoltage spikes, ensuring compliance with safety standards and protecting the electric vehicle from potential damage, while also improving electromagnetic compatibility and reducing the load on pyrofuses.
Implementation Method 1
a capacitive filter is installed on the DC bus and in the electric vehicle charger... the electrical energy in the inductance of the DC bus between the power cabinet and the electric vehicle charger is at least partially absorbed by the capacitive filter
Data Source
AI summary
Described herein is an electric vehicle charging arrangement for charging an electric vehicle. The electric vehicle charging arrangement includes: an electric vehicle charger configured for providing a direct current (DC) to the electric vehicle, a power cabinet configured for providing a DC to the electric vehicle charger, and a direct current bus arranged between the power cabinet and the electric vehicle charger and configured to transport the DC from the power cabinet to the electric vehicle charger, where a capacitive filter is installed on the DC bus and in the electric vehicle charger.