Charging Station Circuit with DC-Isolated Transformer Outputs
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Solution Overview
Problem
Existing charging station circuit systems face challenges in maintaining DC isolation and efficiently adapting voltages for vehicle energy storage, often requiring high primary voltages that exceed safety limits and complicating voltage regulation.
Innovation Solution
A circuit system with DC-isolated transformer outputs, featuring a changeover logic unit that connects DC-DC converters in parallel or series, allowing for voltage range adjustment between 200 V and 1000 V, and incorporating a medium voltage transformer with star and delta circuits to eliminate the need for power factor correction and reduce harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rectifiers are coupled together and their voltages accumulate, then higher voltages are achieved, but voltage requirements for DC-DC converters exceed safety limits and system complexity increases
Solution Approach 1:
The system divides the voltage generation into separate DC-isolated transformer outputs, each feeding its own rectifier and DC-DC converter subsystem. This segmentation prevents voltage accumulation while maintaining flexibility in voltage configuration through the changeover logic unit that can connect outputs in series or parallel.
Solution Approach 2:
The changeover logic unit dynamically reconfigures the connection topology between transformer outputs and DC-DC converters, switching between series and parallel connections based on required output voltage and current demands, thereby adapting the system to different operating conditions without fixed wiring constraints.
2Power
If DC-DC converters are connected in series, then higher output voltages are achieved, but voltage regulation becomes more difficult
Solution Approach 1:
Each DC-DC converter is equipped with independent control that monitors its input and output voltages, allowing precise regulation regardless of connection configuration. The changeover logic unit receives feedback signals and automatically adjusts the connection topology to maintain optimal voltage regulation under varying load conditions.
3Reliability
If transformer outputs are DC-isolated, then safety is improved, but voltage flexibility for different charging requirements is reduced
Solution Approach 1:
The changeover logic unit provides multi-functionality by enabling both series and parallel connection modes of DC-isolated transformer outputs, allowing the same hardware configuration to deliver different voltage and current combinations to meet various charging requirements while maintaining galvanic isolation for safety.
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
This solution ensures DC isolation from the mains supply to the vehicle, reduces voltage requirements for DC-DC converters, and allows for flexible voltage adjustment, enhancing safety and efficiency in charging operations while minimizing harmonics and power factor correction needs.
Implementation Method 1
a transformer with transformer outputs which are DC-isolated from one another
Implementation Method 2
a first subsystem and a second subsystem each comprising a rectifier which has a DC-DC converter connected upstream of it
Data Source
AI summary
A circuit system for a charging station which is configured to charge an energy store in a vehicle, the circuit system including a transformer with transformer outputs which are DC-isolated from one another, a first subsystem and a second subsystem each being connected to one of the transformer outputs. The first subsystem and the second subsystem each include a rectifier which has a DC-DC converter connected upstream of it, the DC-DC converter being coupled to a changeover logic unit on its input side or on its output side. In particular, provision is made for the first subsystem to be connected to a delta circuit in the transformer output and for the second subsystem to be connected to a star circuit in the transformer output.