Common Transformer for Bi-Directional EV Power Conversion
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Solution Overview
Problem
Existing on-board charging systems for electric vehicles face challenges in efficiently managing and regulating the bi-directional flow of electrical current between alternating current (AC) and direct current (DC) circuits, particularly in handling high-voltage and low-voltage DC systems, which affects the charging efficiency and vehicle-to-grid power supply.
Innovation Solution
A common transformer with a transformer core configured to receive electrical windings from multiple circuits, incorporating AC synchronous rectification, high-voltage DC, and low-voltage DC circuits, enables bi-directional induction of electrical current through a specific ratio of wire turns and microprocessor-controlled switches, facilitating efficient voltage regulation and power flow between AC, high-voltage DC, and low-voltage DC circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate transformers are used for AC-DC and DC-DC conversion, then voltage regulation for each circuit is independent and reliable, but device complexity and space occupation increase
Solution Approach 1:
The patent combines multiple transformers (AC-DC transformer, DC-DC transformer, and common mode choke) into a single integrated transformer structure with a shared core. The primary winding connects to AC input, while secondary windings provide both high-voltage DC and low-voltage DC outputs. This merging reduces the number of separate components, simplifies the overall system structure, and decreases space occupation while maintaining the functional separation needed for reliable voltage regulation in different circuits.
Solution Approach 2:
The integrated transformer performs multiple functions simultaneously: it provides AC-DC conversion for the charging circuit, DC-DC conversion for the power distribution circuit, and common mode noise filtering through the shared core structure. This multi-functionality eliminates the need for separate dedicated transformers for each function, reducing device complexity while maintaining the reliability of voltage regulation across all circuits.
2Device complexity
If a common transformer is used for AC-DC and DC-DC conversion, then device complexity and space occupation are reduced, but voltage regulation between different circuits becomes more difficult
Solution Approach 1:
The integrated transformer is designed with distinct primary and secondary windings that are electrically isolated but magnetically coupled through the shared core. The primary winding handles AC input, while separate secondary windings provide independently regulated high-voltage DC and low-voltage DC outputs. This segmentation of windings maintains clear functional boundaries within the integrated structure, making voltage regulation for each circuit independent and controllable despite the physical integration.
Solution Approach 2:
The shared magnetic core acts as an intermediary that enables controlled energy transfer between different circuits while maintaining electrical isolation. Through the magnetic coupling in the common core, voltage regulation can be achieved by controlling the turns ratio between windings and using rectification circuits on the secondary side, allowing independent voltage regulation for each output circuit while benefiting from the integrated structure.
3Reliability
If separate transformers are used for AC-DC and DC-DC conversion, then voltage regulation for each circuit is independent, but manufacturing cost and assembly time increase
Solution Approach 1:
The patent integrates multiple transformer functions into a single manufactured component with a shared core and multiple windings. This merging allows all windings to be wound and assembled simultaneously during manufacturing, reducing the number of separate assembly operations needed. The integrated structure can be manufactured as a single unit, decreasing assembly time and manufacturing cost while maintaining the electrical isolation and independent regulation capabilities of separate transformers.
4Productivity
If a common transformer is used with bi-directional power flow, then charging efficiency and vehicle-to-grid capability are improved, but control complexity increases
Solution Approach 1:
The integrated transformer enables dynamic bi-directional power flow control by adjusting the phase and amplitude of switching signals for the power electronic devices connected to its windings. The same transformer structure supports both charging mode (AC to DC) and vehicle-to-grid mode (DC to AC) by dynamically changing the operating state of the windings and associated switching circuits, achieving improved productivity through flexible control without requiring separate hardware for each direction.
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 enables efficient bi-directional power flow, optimizing charging efficiency and enabling vehicle-to-grid power supply by regulating voltage across different circuits, thus enhancing the overall performance of electric vehicle charging systems.
Implementation Method 1
a transformer core configured to receive electrical windings from a plurality of electrical circuits
Data Source
AI summary
A common transformer used with an electric vehicle that includes a transformer core configured to receive electrical windings from a plurality of electrical circuits; an alternating current (AC) synchronous rectification (SR) circuit electrically connected to the transformer core via an AC winding; a high-voltage SR DC circuit electrically connected to the transformer core via a high-voltage DC winding; and a low-voltage DC SR circuit electrically connected to the transformer core via a low-voltage DC winding.