Three-Phase Transformer Switching for Wide-Voltage EV Charging
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Solution Overview
Problem
Existing charging piles face challenges in adapting to a wide range of output voltages required by different electric vehicles due to limited adjustment range of the switching frequency of the inverter circuit, leading to inefficiencies and reduced practicality.
Innovation Solution
A power supply apparatus incorporating a three-phase transformer circuit with a turns ratio switching circuit and a connection relationship switching circuit, allowing for adjustment of the transformer's turns ratio and the connection manner of three-phase rectifier bridge circuits to achieve a wide range of output voltages, thereby optimizing conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the switching frequency of the inverter circuit is adjusted to change output voltage, then the output voltage can be adapted to different electric vehicles, but the conversion efficiency deteriorates due to the limited adjustment range of switching frequency
Solution Approach 1:
The patent applies dynamics by making the transformer turns ratio adjustable through switching circuits. The primary winding is divided into multiple sections that can be selectively connected to change the effective turns ratio dynamically. This allows the system to adapt output voltage without relying solely on switching frequency adjustment, thereby maintaining conversion efficiency while expanding voltage adaptability.
Solution Approach 2:
The patent changes the parameter of transformer turns ratio by providing multiple winding configurations. The primary winding includes first and second windings that can be connected in different configurations (series, parallel, or isolated) to achieve different turns ratios. This parameter change enables wide output voltage range while keeping the switching frequency within an efficient range.
2Loss of energy
If the switching frequency is limited to maintain conversion efficiency, then energy loss is reduced, but the output voltage range deteriorates due to limited adjustment capability
Solution Approach 1:
The patent introduces dynamic adjustability to the transformer turns ratio through switching circuits. The primary winding sections can be selectively connected to change the effective turns ratio according to the required output voltage, enabling wide voltage adaptability without expanding the switching frequency range beyond efficient operating conditions.
Solution Approach 2:
The primary winding is segmented into multiple sections (first winding and second winding) that can be independently controlled. This segmentation allows flexible combination to achieve different turns ratios, expanding the output voltage range while maintaining efficient conversion by keeping switching frequency within optimal limits.
3Device complexity
If a single transformer configuration is used, then the device structure is simple, but the output voltage range deteriorates due to limited turns ratio adjustment
Solution Approach 1:
The primary winding is divided into multiple sections that can be selectively connected through switching circuits. This segmentation enables different effective turns ratios to be achieved by connecting different sections in series or parallel, expanding the output voltage range while maintaining a relatively simple transformer structure without requiring multiple separate transformers.
Solution Approach 2:
The patent introduces dynamic switching capability to the transformer structure. The switching circuit selectively connects different primary winding sections based on the required output voltage, making the transformer configuration adaptable without requiring complex multi-transformer arrangements.
4Reliability
If the turns ratio of the transformer is fixed, then the device structure is simple and reliable, but the output voltage range deteriorates due to inability to adapt to different vehicle requirements
Solution Approach 1:
The patent implements dynamic turns ratio adjustment through switching circuits that selectively connect different primary winding sections. This maintains reliability by using a single transformer core with well-defined winding configurations, while achieving adaptability through controlled switching between different effective turns ratios to meet various vehicle charging requirements.
Solution Approach 2:
The primary winding is segmented into controllable sections that can be independently switched. This segmentation allows the system to maintain a simple and reliable single-transformer structure while achieving multiple effective turns ratios by connecting different segments in different configurations.
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 solution enables the charging pile to efficiently provide a wide range of output voltages, effectively meeting the voltage requirements of various electric vehicles by adjusting the transformer's running mode and the connection of rectifier bridge circuits, thus enhancing its practicality and efficiency.
Implementation Method 1
A three-phase primary winding of the three-phase transformer is configured to receive a three-phase alternating current. A three-phase secondary winding of the three-phase transformer is configured to output a three-phase alternating current
Data Source
AI summary
A power supply apparatus, a three-phase transformer circuit, and a charging pile. The power supply apparatus includes a turns ratio switching circuit, a connection relationship switching circuit, a three-phase transformer, and two three-phase rectifier bridge circuits. A three-phase primary winding of the three-phase transformer is configured to receive a three-phase alternating current. A three-phase secondary winding of the three-phase transformer is configured to output a three-phase alternating current to each of the two three-phase rectifier bridge circuits. A running mode of the three-phase transformer includes a first turns ratio mode and a second turns ratio mode. The turns ratio switching circuit is configured to switch a quantity of turns of the three-phase primary winding, to switch the running mode of the three-phase transformer.