EVSE Relay Isolation Layout for High-Power Charging Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle charging solutions face challenges in optimal power use and safety, particularly in modes 3 and 4, with potential damage to sockets and limited charging capacity, and there is a need for improved safety and efficiency in EV charging systems.
Innovation Solution
An electric vehicle supply equipment (EVSE) with internal circuitry featuring a primary set of seven relays and a safety relay, configured to connect or disconnect power based on input signals, ensuring efficient and safe charging by dynamically balancing load and providing immediate power cutoff in case of faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Mode 3 charging with dedicated circuit of 16A or more is used, then charging capacity is increased to 22 kW or more, but safety risks and potential damage to sockets increase
Solution Approach 1:
The patent implements a preliminary safety check by testing the earth continuity before charging begins. The control unit measures the resistance between the earth conductor and functional earth terminal, and only permits charging if the resistance is below a predetermined threshold. This preliminary action prevents safety issues before they can occur during high-power charging.
Solution Approach 2:
The patent introduces an intermediary safety mechanism in the form of a隔离 transformer that electrically isolates the charging circuit from the grid. This intermediary device allows high-power charging to proceed while protecting the socket and surrounding equipment from potential damage through galvanic isolation.
2Reliability
If Mode 2 charging via socket outlets is used, then charging can be performed with protection device, but charging is limited to 10A and 2.3 kW
Solution Approach 1:
The patent segments the charging system into distinct functional modules: a socket interface unit, a control unit with earth testing capability, and a power delivery unit. This segmentation allows the socket to remain simple and safe for user connection, while the control unit performs safety checks and the power unit delivers high capacity charging, thus achieving both safety and high power.
3Ease of operation
If standard socket outlets are used for EV charging, then charging can be performed, but long charging time and heating of sockets and cables occur
Solution Approach 1:
The patent implements dynamic power adjustment based on real-time monitoring of temperature and earth resistance. The control unit continuously monitors system conditions and dynamically adjusts the charging current to optimize charging speed while preventing overheating. This dynamic control allows the system to operate at higher powers when conditions permit, reducing overall charging time.
Data Source
AI summary
The disclosure relates to an electric vehicle supply equipment for charging electrical vehicles comprising internal circuitry with an input of isolated conductors; an output of isolated conductors being arranged to be connected to the input conductors, the output conductors being connectable to an electric vehicle for providing power for charging at least one battery; a primary set of relays, each relay within the set being configured to selectively connect or disconnect electrical power provided from the main distribution cable via the input conductors to the output of isolated conductors, characterized in that the primary set of relays consists/comprises of seven relays, configured to selectively connect or disconnect electrical power provided from the main distribution cable via the input conductors in response to a second input signal; and a safety relay, configured to connect or disconnect electrical power provided from the main distribution cable in response to a first input signal.