Bidirectional EV Charger Topology for Wide-Voltage V2V Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for high efficiency electric vehicle (EV) chargers that can handle a wide range of input/output voltages and provide vehicle-to-vehicle (V2V) charging capability, especially in scenarios where grid power is unavailable.
Innovation Solution
The charger is designed with a variable transformer to partition the output voltage range into subranges, and the switching frequency of the DC-DC converter can be doubled to reduce peak current. It features two outputs for multiple charging modes, including V2V charging, and uses bidirectional DC-DC converters for efficient power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the charger uses a standard AC-DC converter stage followed by DC-DC converters, then it can charge electric vehicles with different battery voltages, but the charging efficiency decreases and power loss increases
Solution Approach 1:
The patent extracts and removes the AC-DC converter stage from the charging system. By directly connecting the AC grid to the DC-DC converters through a switchgear system, the unnecessary AC-DC conversion step is eliminated, reducing energy loss while maintaining the ability to charge vehicles with different battery voltages through the DC-DC converters alone
Solution Approach 2:
The patent segments the charging system into independent DC-DC converter modules that can operate independently. Each DC-DC converter can handle specific voltage ranges, and the system can selectively activate only the necessary converters based on the connected vehicle's requirements, improving efficiency by avoiding unnecessary power conversion stages
2Adaptability or versatility
If the charger is designed to handle wide voltage ranges for all EV types, then it can serve diverse electric vehicles, but the device complexity and cost increase
Solution Approach 1:
The patent implements universal DC-DC converter modules that can adapt to different voltage requirements through controlled switching. Instead of designing separate chargers for different voltage ranges, the same modular DC-DC converter architecture can serve multiple voltage requirements by adjusting switching configurations, simplifying the overall system while maintaining versatility
Solution Approach 2:
The patent uses dynamic switching control to adapt the charger configuration in real-time based on the connected vehicle's battery voltage. The switchgear system dynamically reconfigures the circuit topology, and the DC-DC converters adjust their operating parameters on-the-fly, allowing a single static hardware design to handle dynamic voltage requirements
3Productivity
If the charger operates at high currents to provide fast charging, then the charging speed increases, but the charger overheats and efficiency decreases
Solution Approach 1:
The patent changes the operating parameters of the DC-DC converters to optimize the balance between charging speed and temperature. By adjusting switching frequencies, duty cycles, and power distribution across multiple parallel converters, the system can deliver high charging currents while distributing thermal load, preventing overheating and maintaining efficiency even at high power levels
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 charger achieves high efficiency, up to 98%, by bypassing the AC-DC converter stage and using only two DC-DC converters for V2V charging, enabling effective charging of EVs in various voltage ranges and remote areas without grid power.
Implementation Method 1
the charger can include a variable transformer to partition the output voltage range into multiple subranges
Implementation Method 2
The charging process can use the battery of the service vehicle... The charger can be configured with 2 outputs, which can be configured for multiple modes of charging, including charging one electric vehicle from another electric vehicle
Data Source
AI summary
An EV charger has an AC-DC converter coupled to two DC-DC converters can be configured with V2V charging capability, together with a wide range of input/output voltages for accepting existing electric vehicle available on the market. The charger can include a variable transformer to partition the output voltage range into multiple subranges. In addition, the switching frequency of the DC-DC converter can be doubled when the voltage gain of the DC-DC converter deviates significantly from unity.