Parallel Transformer Converting Circuit for Lower-Cost EV Charging
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Solution Overview
Problem
The existing on-board charger (OBC) circuits for electric vehicles have complex structures, high costs, and low conversion efficiency due to the use of multiple EMI filters and DC/DC converters, leading to increased complexity and cost.
Innovation Solution
A converting circuit design that includes parallel-connected primary-side and secondary-side converting circuits, transformers, and a controller to adjust voltage phase differences, reducing the need for additional transformers and simplifying the circuit structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a three-port network with multiple DC/DC converters and EMI filters is used to implement voltage conversion functions, then the voltage conversion capability is improved, but the circuit structure becomes complex and conversion efficiency decreases
Solution Approach 1:
The patent merges multiple DC/DC converter functions into a single integrated circuit structure. The first and second primary-side converting circuits are connected in parallel to the same primary-side winding, and the first and second secondary-side converting circuits are connected in parallel to the same secondary-side winding, eliminating the need for separate DC/DC converter stages and reducing overall circuit complexity while maintaining voltage conversion capability
Solution Approach 2:
The single transformer with parallel-connected converting circuits serves multiple functions simultaneously. The circuit can perform both voltage step-up and voltage step-down operations by controlling the switching of the primary-side and secondary-side converting circuits, making the circuit structure universal and adaptable to different voltage conversion requirements without needing separate dedicated circuits
2Adaptability or versatility
If multiple intermediate links and DC/DC converters are used to handle power conversion, then the voltage adaptability is improved, but power loss increases and conversion efficiency decreases
Solution Approach 1:
The patent extracts and eliminates unnecessary intermediate conversion stages from the power conversion path. By directly connecting the primary-side and secondary-side converting circuits through the transformer, the design removes redundant DC/DC converter stages and EMI filters that were previously required, thereby reducing the number of power conversion steps and minimizing cumulative power losses
Solution Approach 2:
The parallel-connected converting circuits enable continuous and direct power transfer from the primary side to the secondary side through the transformer. The circuit maintains continuous useful action by allowing power to flow directly through the intended conversion path without interruption or redirection through multiple intermediate stages, thereby improving overall conversion efficiency
3Adaptability or versatility
If a DC/DC converter with wide input range is used to handle the power battery's large voltage range, then the voltage range adaptability is improved, but the circuit structure becomes more complex and costs increase
Solution Approach 1:
The patent employs dynamic control of the primary-side and secondary-side converting circuits to adapt to the power battery's large voltage range. By dynamically switching between different converting circuit configurations and adjusting the duty cycles of the switches, the circuit can handle varying input voltages without requiring a specially designed wide-input-range DC/DC converter, thus maintaining simplicity while achieving adaptability
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 design effectively reduces circuit complexity, volume, and costs while improving conversion efficiency by reusing parallel-connected circuits and optimizing voltage control.
Implementation Method 1
a first transformer T1, a second transformer T2, and a third transformer T3... The first primary-side converting circuit is connected to a primary side of the first transformer. The first secondary-side converting circuit is connected to a secondary side of the first transformer
Data Source
AI summary
A converting circuit and a charging apparatus and relates to the field of electronic technologies. In the converting circuit, two groups of parallel connected primary-side converting circuits are connected in a one-to-one correspondence with a primary side of a first transformer and a primary side of a second transformer, and two groups of parallel connected secondary-side converting circuits are connected in a one-to-one correspondence with a secondary side of the first transformer and a secondary side of the second transformer, and the two groups of parallel connected primary-side converting circuits or the two groups of parallel connected secondary-side converting circuits include a first input end and a second input end separately connected to a primary side of a third transformer. Therefore, a primary-side converting circuit does not need to be disposed for the third transformer, to effectively reduce circuit complexity and reduce the circuit costs.