EV Charging Arrangement Dynamic Y-Capacitance Management
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Solution Overview
Problem
The existing electric vehicle charging infrastructure faces challenges in accommodating both 'older' and 'newer' vehicles due to the Y-capacitance limitations, which are insufficient for high-power charging while needing to maintain backward compatibility and comply with EMC requirements.
Innovation Solution
The electric vehicle charging arrangement dynamically adjusts the number of power stages connected in parallel or series based on the Y-capacitance and vehicle information, allowing for flexible charging currents and voltages by using a control device to negotiate the Y-capacitance for each charging session, ensuring compatibility with various vehicle standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If more power stages are connected in parallel to increase charging current for fast charging, then charging power is improved, but Y-capacitance increases beyond safety limits for older vehicles
Solution Approach 1:
The system dynamically adjusts the configuration of power stages by switching between parallel and series connections based on the detected vehicle type. For newer vehicles, power stages are connected in parallel to provide high charging current (exceeding 500A). For older vehicles, power stages are connected in series to limit Y-capacitance exposure while still providing charging capability. This dynamic reconfiguration resolves the contradiction between providing high power and maintaining safety limits.
Solution Approach 2:
The system changes the electrical parameters (voltage and current) by reconfiguring the power stage connections. When switching from parallel to series connection, the voltage doubles while the current capability is halved, effectively adapting the charging parameters to match the vehicle's requirements and Y-capacitance tolerance. This parameter transformation allows the same hardware to serve both high-power and low-Y-capacitance scenarios.
2Reliability
If Y-capacitance is limited to 500nF per rail to protect against electric shocks, then safety is improved, but charging power is insufficient for fast charging
Solution Approach 1:
The system dynamically changes its operational mode based on the vehicle type detected during the charging session. For older vehicles with strict Y-capacitance limits, the system operates in a safe mode with limited power stages connected in parallel. For newer vehicles that can tolerate higher Y-capacitance, the system switches to high-power mode with more power stages connected in parallel, thereby achieving fast charging capabilities while maintaining safety for all vehicle types.
Solution Approach 2:
The charging system is divided into multiple independent power stages, each with its own Y-capacitance. By selectively connecting different numbers of these segmented power stages in parallel or series, the system can adjust the total Y-capacitance exposure to match the vehicle's tolerance while providing appropriate charging power. This segmentation allows flexible adaptation to different safety requirements.
3Productivity
If multiple power stages are connected in parallel to provide maximum charging current, then charging speed is improved, but compatibility with older vehicles is lost
Solution Approach 1:
The system employs dynamic configuration of power stages that can be switched between parallel and series connections based on real-time detection of vehicle type. During the charging session setup, the control device communicates with the vehicle to determine its Y-capacitance tolerance and charging capabilities. Based on this information, the system dynamically selects the appropriate configuration: parallel connection for high-speed charging of newer vehicles, or series connection for compatibility with older vehicles. This dynamic adaptation ensures both high productivity when possible and broad versatility.
Solution Approach 2:
The charging system is designed with multi-functional capability to serve both newer high-power vehicles and older conventional vehicles using the same infrastructure. By incorporating switches that can reconfigure power stages between parallel and series connections, a single charging station becomes universal, capable of adapting its output characteristics to match different vehicle requirements without needing separate charging infrastructure for different vehicle types.
Data Source
Figure 1
AI summary
The invention relates to an electric vehicle charging arrangement comprising an electric vehicle supply equipment, EVSE, (1) and an electric vehicle (2), the EVSE (1) comprising a plurality of power stages (3) each configured for providing electrical energy to charge the electrical vehicle (2) and each comprising a Y-capacitance (4), at least one outlet (9) configured for connecting the electrical vehicle (2) to at least one of the power stages (3) for charging the electrical vehicle (2), at least one switch (7) configured for connecting two power stages (3) in parallel and/or in series, and a control device (10) and/or the electric vehicle (2) are configured for switching the at least one switch (7) based on the Y-capacitance (4) and on a vehicle information.