Three-Phase Resonant DC-DC Converter for Low-Ripple EV Charging
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Solution Overview
Problem
High-power on-board chargers for electric vehicles face challenges with high costs and complex hardware and software requirements due to multi-module parallel connections, which also result in large output ripple currents and difficulties in optimizing costs and volume.
Innovation Solution
A three-phase interleaved resonance bidirectional DC-DC converter with a first and second adjustment module, a resonance module, a current detection module, and a controller, which allows for bidirectional energy transmission with reduced output ripple current and overcurrent protection, using fewer devices to lower costs and enhance monitoring precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-module parallel connection is used for high-power bidirectional DC-DC converter, then power capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple DC-DC converter modules into a single integrated bidirectional DC-DC converter. This consolidation achieves high-power capability through unified power processing circuits while reducing the number of independent control systems and simplifying overall system architecture, thereby resolving the contradiction between power capability and system complexity
2Power
If multi-module parallel connection is used for high-power bidirectional DC-DC converter, then power capability is improved, but manufacturing cost increases
Solution Approach 1:
By consolidating multiple converter functions into a single integrated device, the patent reduces the total component count, simplifies assembly processes, and lowers manufacturing costs while maintaining high-power bidirectional conversion capability
3Device complexity
If output current feedback is used for current monitoring, then system complexity is reduced, but measurement precision and response speed decrease
Solution Approach 1:
The patent introduces a current transformer as an intermediary device to directly sense the primary current. This transformer provides isolated, high-precision current measurement with fast response characteristics, enabling accurate monitoring without complicating the overall control system architecture
4Device complexity
If no direct current monitoring is implemented, then device complexity is reduced, but reliability under overcurrent conditions deteriorates
Solution Approach 1:
The patent implements real-time current feedback through a current transformer that continuously monitors the primary current and provides signals to the control system. This enables immediate detection of overcurrent conditions and rapid protective action, significantly improving system reliability while keeping the monitoring circuit relatively simple
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 high-power charging and discharging with small output ripple current, fast response, and reliable overcurrent protection, reducing the risk of damage from overloading while minimizing device usage and optimizing system design.
Implementation Method 1
the resonance module is configured to: resonate an output signal of the first adjustment module when the battery module of the vehicle is charged by the external, or resonate an output signal of the second adjustment module when the battery module is discharged by the external
Data Source
AI summary
A DC-DC converter, an on-board charger, and an electric vehicle are disclosed. The DC-DC converter includes: a first adjustment module, a resonance module, a second adjustment module, a current detection module, and a controller. The current detection module is configured to detect a current signal of the resonance module; and the controller is configured to control the first adjustment module and the second adjustment module to reduce an output power when the current signal is greater than a current threshold. By directly detecting the current signal of the resonance module, a high precision and a faster response are achieved.