Integrated Solid-State Transformer for EV Charging Isolation
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Solution Overview
Problem
Traditional power supply systems for electric vehicle charging, particularly those using IT earthing systems, face challenges such as inefficient charging due to lower voltage, risk of undetected earth faults, and increased costs and complexity with traditional isolation transformers, which result in longer charging times, higher noise levels, and increased fire hazards.
Innovation Solution
A power supply system incorporating a solid-state transformer integrated with an EVSE control device, capable of voltage conversion and galvanic isolation, which allows for efficient charging by converting between different earthing systems (IT, TN, TT) and enabling adaptive charging speed, remote monitoring, and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional isolation transformer is used for voltage conversion and galvanic isolation, then charging safety is improved, but device complexity, noise level, and fire hazard increase
Solution Approach 1:
The patent combines the isolation transformer and EVSE control device into a single integrated unit. The transformer windings are arranged such that the primary winding is electrically connected to the power source and the secondary winding to the vehicle charging system, with control circuits integrated within the same housing. This merging eliminates the need for separate isolation transformer and control device installations, reducing overall system complexity while maintaining galvanic isolation and safety functions.
2Reliability
If a traditional isolation transformer is used for voltage conversion, then galvanic isolation is achieved, but noise level and fire hazard increase
Solution Approach 1:
The patent replaces the traditional mechanical/ electromagnetic isolation transformer with a solid-state isolation solution using DC-DC converters or DC-AC-DC conversion stages. The control device converts AC input voltage to DC, provides galvanic isolation through solid-state switching circuits, and then converts to the required output voltage. This substitution eliminates the mechanical components and magnetic core noise associated with traditional transformers, significantly reducing noise levels while maintaining galvanic isolation.
3Device complexity
If IT earthing system is used for power supply, then system simplicity is maintained, but charging efficiency decreases due to lower voltage
Solution Approach 1:
The patent incorporates voltage conversion functionality within the integrated control device to transform the lower voltage IT earthing system output (typically 230V phase-to-phase) into the higher voltage required for efficient EV charging (400V or higher). The control device includes rectification, isolation, and inversion stages that change the voltage parameters, enabling three-phase charging capability even when supplied from IT system outlets, thereby significantly improving charging efficiency without requiring complex external transformation equipment.
4Reliability
If traditional separate isolation transformer and EVSE units are used, then functional requirements are met, but costs increase
Solution Approach 1:
The patent integrates the isolation transformer, EVSE control device, voltage conversion circuits, and monitoring functions into a single unified unit. The housing contains all necessary components including the transformer windings, control circuits, communication interfaces, and protection devices. This consolidation eliminates the need for purchasing and installing separate isolation transformer and EVSE units, reducing overall system cost while maintaining all required safety and functional characteristics.
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 system significantly reduces charging time, enhances safety, and lowers costs by integrating the transformer and EVSE into a single unit, providing efficient voltage conversion, adaptive charging, and remote monitoring, while minimizing noise and aesthetic issues.
Implementation Method 1
an isolation transformer allowing at least one of electric isolation and voltage conversion between a primary power source and the vehicle charging system
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
The invention concerns a power supply system suitable for converting and/or isolating charging power supplied to a vehicle charging system within battery operated vehicle. The system comprises an isolation transformer allowing at least one of electric isolation and voltage conversion between a primary power source and the vehicle charging system. The transformer comprises a primary side wherein one or more terminals of the primary side are electrically connectable to the primary power source and a secondary side, wherein one or more terminals of the secondary side are electrically connectable to the vehicle charging system, an EVSE control device electrically connectable to the vehicle charging system, a data communication line connected to the EVSE control device and connectable to the vehicle charging system, which data communication line allows, when connected to the vehicle charging system, transmission of control signals to the vehicle charging system, monitoring coupling between secondary side and the vehicle charging system and monitoring at least one parameter related to the charging status of the vehicle charging system during charging. The power supply system is further characterized in that the isolation transformer is a solid state transformer and further that the isolation transformer and the EVSE control device constitutes an integrated unit, i.e. physically arranged in common unit. The invention also concerns a computer program product for monitoring information from the power supply system.